heterogeneous power quality: Topics by WorldWideScience.org

Sample records for heterogeneous power quality

Heterogeneity in pineapple fruit quality results from plant heterogeneity at flower induction.

Science.gov (United States)

Fassinou Hotegni, V Nicodème; Lommen, Willemien J M; Agbossou, Euloge K; Struik, Paul C

2014-01-01

Heterogeneity in fruit quality constitutes a major constraint in agri-food chains. In this paper the sources of the heterogeneity in pineapple in the field were studied in four experiments in commercial pineapple fields. The aims were to determine (a) whether differences in pineapple fruit quality among individual fruits are associated with differences in vigor of the individual plants within the crop at the time of artificial flower induction; and (b) whether the side shoots produced by the plant during the generative phase account for the fruit quality heterogeneity. Two pineapple cultivars were considered: cv. Sugarloaf and cv. Smooth Cayenne. Plant vigor at the time of artificial flower induction was measured by three variates: the number of functional leaves, the D-leaf length and their cross product. Fruit quality attributes measured at harvest time included external attributes (weight and height of fruit, infructescence and crown) and internal quality attributes [total soluble solids (TSS), pH, translucent flesh]. Results showed that the heterogeneity in fruit weight was a consequence of the heterogeneity in vigor of the plants at the moment of flower induction; that effect was mainly on the infructescence weight and less or not on the crown weight. The associations between plant vigor variates at flower induction and the internal quality attributes of the fruit were poor and/or not consistent across experiments. The weight of the slips (side shoots) explained part of the heterogeneity in fruit weight, infructescence weight and fruit height in cv. Sugarloaf. Possibilities for reducing the variation in fruit quality by precise cultural practices are discussed.
Heterogeneity in pineapple fruit quality results from plant heterogeneity at flower induction

Directory of Open Access Journals (Sweden)

V. Nicodeme eFassinou Hotegni

2014-12-01

Full Text Available Heterogeneity in fruit quality constitutes a major constraint in agri-food chains. In this paper the sources of the heterogeneity in pineapple in the field were studied in four experiments in commercial pineapple fields. The aims were to determine (a whether differences in pineapple fruit quality among individual fruits are associated with differences in vigor of the individual plants within the crop at the time of artificial flower induction; and (b whether the side shoots produced by the plant during the generative phase account for the fruit quality heterogeneity. Two pineapple cultivars were considered: cv. Sugarloaf and cv. Smooth Cayenne. Plant vigor at the time of artificial flower induction was measured by three variates: the number of functional leaves, the D-leaf length and their cross product. Fruit quality attributes measured at harvest time included external attributes (weight and height of fruit, infructescence and crown and internal quality attributes (total soluble solids, pH, translucent flesh. Results showed that the heterogeneity in fruit weight was a consequence of the heterogeneity in vigor of the plants at the moment of flower induction; that effect was mainly on the infructescence weight and less or not on the crown weight. The association between plant vigor variates at flower induction and the internal quality attributes of the fruit were poor and/or not consistent across experiments. The weight of the slips (side shoots, explained part of the heterogeneity in fruit weight, infructescence weight and fruit height in cv. Sugarloaf. Possibilities for reducing the variation in fruit quality by precise cultural practices are discussed.
On the Dual-Decomposition-Based Resource and Power Allocation with Sleeping Strategy for Heterogeneous Networks

KAUST Repository

Alsharoa, Ahmad M.; Ghazzai, Hakim; Yaacoub, Elias; Alouini, Mohamed-Slim

2015-01-01

In this paper, the problem of radio and power resource management in long term evolution heterogeneous networks (LTE HetNets) is investigated. The goal is to minimize the total power consumption of the network while satisfying the user quality
Unobserved heterogeneity in the power law nonhomogeneous Poisson process

International Nuclear Information System (INIS)

Asfaw, Zeytu Gashaw; Lindqvist, Bo Henry

2015-01-01

A study of possible consequences of heterogeneity in the failure intensity of repairable systems is presented. The basic model studied is the nonhomogeneous Poisson process with power law intensity function. When several similar systems are under observation, the assumption that the corresponding processes are independent and identically distributed is often questionable. In practice there may be an unobserved heterogeneity among the systems. The heterogeneity is modeled by introduction of unobserved gamma distributed frailties. The relevant likelihood function is derived, and maximum likelihood estimation is illustrated. In a simulation study we then compare results when using a power law model without taking into account heterogeneity, with the corresponding results obtained when the heterogeneity is accounted for. A motivating data example is also given. - Highlights: • Consequences of overlooking heterogeneity in similar repairable systems are studied. • Likelihood functions are established for power law NHPP w/ and w/o heterogeneity. • ML estimators for parameters of power law NHPP with heterogeneity are derived. • A simulation study shows the effects of heterogeneity and its ignorance in models
Generative Adversarial Networks Based Heterogeneous Data Integration and Its Application for Intelligent Power Distribution and Utilization

Directory of Open Access Journals (Sweden)

Yuanpeng Tan

2018-01-01

Full Text Available Heterogeneous characteristics of a big data system for intelligent power distribution and utilization have already become more and more prominent, which brings new challenges for the traditional data analysis technologies and restricts the comprehensive management of distribution network assets. In order to solve the problem that heterogeneous data resources of power distribution systems are difficult to be effectively utilized, a novel generative adversarial networks (GANs based heterogeneous data integration method for intelligent power distribution and utilization is proposed. In the proposed method, GANs theory is introduced to expand the distribution of completed data samples. Then, a so-called peak clustering algorithm is proposed to realize the finite open coverage of the expanded sample space, and repair those incomplete samples to eliminate the heterogeneous characteristics. Finally, in order to realize the integration of the heterogeneous data for intelligent power distribution and utilization, the well-trained discriminator model of GANs is employed to check the restored data samples. The simulation experiments verified the validity and stability of the proposed heterogeneous data integration method, which provides a novel perspective for the further data quality management of power distribution systems.
Heterogeneity in pineapple fruit quality results from plant heterogeneity at flower induction

NARCIS (Netherlands)

Fassinou Hotegni, V.N.; Lommen, W.J.M.; Agbossou, E.K.; Struik, P.C.

2014-01-01

Heterogeneity in fruit quality constitutes a major constraint in agri-food chains. In this paper the sources of the heterogeneity in pineapple in the field were studied in four experiments in commercial pineapple fields. The aims were to determine (a) whether differences in pineapple fruit quality
Purchasing Power Parity and Heterogeneous Mean Reversion

NARCIS (Netherlands)

C.G. Koedijk (Kees); B. Tims (Ben); M.A. van Dijk (Mathijs)

2005-01-01

textabstractThis paper analyzes the properties of multivariate tests of purchasing power parity (PPP) that fail to take heterogeneity in the speed of mean reversion across real exchange rates into account. We compare the performance of homogeneous and heterogeneous unit root testing methodologies.
Energy Harvesting in Heterogeneous Networks with Hybrid Powered Communication Systems

KAUST Repository

Alsharoa, Ahmad

2018-02-12

In this paper, we investigate an energy efficient and energy harvesting (EH) system model in heterogeneous networks (HetNets) where all base stations (BSS) are equipped to harvest energy from renewable energy sources. We consider a hybrid power supply of green (renewable) and traditional micro-grid, such that traditional micro-grid is not exploited as long as the BSS can meet their power demands from harvested and stored green energy. Therefore, our goal is to minimize the networkwide energy consumption subject to users\\' certain quality of service and BSS\\' power consumption constraints. As a result of binary BS sleeping status and user-cell association variables, proposed is formulated as a binary linear programming (BLP) problem. A green communication algorithm based on binary particle swarm optimization is implemented to solve the problem with low complexity time.
Fast decision algorithms in low-power embedded processors for quality-of-service based connectivity of mobile sensors in heterogeneous wireless sensor networks.

Science.gov (United States)

Jaraíz-Simón, María D; Gómez-Pulido, Juan A; Vega-Rodríguez, Miguel A; Sánchez-Pérez, Juan M

2012-01-01

When a mobile wireless sensor is moving along heterogeneous wireless sensor networks, it can be under the coverage of more than one network many times. In these situations, the Vertical Handoff process can happen, where the mobile sensor decides to change its connection from a network to the best network among the available ones according to their quality of service characteristics. A fitness function is used for the handoff decision, being desirable to minimize it. This is an optimization problem which consists of the adjustment of a set of weights for the quality of service. Solving this problem efficiently is relevant to heterogeneous wireless sensor networks in many advanced applications. Numerous works can be found in the literature dealing with the vertical handoff decision, although they all suffer from the same shortfall: a non-comparable efficiency. Therefore, the aim of this work is twofold: first, to develop a fast decision algorithm that explores the entire space of possible combinations of weights, searching that one that minimizes the fitness function; and second, to design and implement a system on chip architecture based on reconfigurable hardware and embedded processors to achieve several goals necessary for competitive mobile terminals: good performance, low power consumption, low economic cost, and small area integration.
Information-Quality based LV-Grid-Monitoring Framework and its Application to Power-Quality Control

DEFF Research Database (Denmark)

Findrik, Mislav; Kristensen, Thomas le Fevre; Hinterhofer, Thomas

2015-01-01

The integration of unpredictable renewable energy sources into the low voltage (LV) power grid results in new challenges when it comes to ensuring power quality in the electrical grid. Addressing this problem requires control of not only the secondary substation but also control of flexible assets...... inside the LV grid. In this paper we investigate how the flexibility information of such assets can be accessed by the controller using heterogeneous off-the-shelf communication networks. To achieve this we develop an adaptive monitoring framework, through which the controller can subscribe to the assets......' flexibility information through an API. We define an information quality metric making the monitoring framework able to adapt information access strategies to ensure the information is made available to the controller with the highest possible information quality. To evaluate the monitoring framework...
Gender-heterogeneous working groups produce higher quality science.

Directory of Open Access Journals (Sweden)

Lesley G Campbell

Full Text Available Here we present the first empirical evidence to support the hypothesis that a gender-heterogeneous problem-solving team generally produced journal articles perceived to be higher quality by peers than a team comprised of highly-performing individuals of the same gender. Although women were historically underrepresented as principal investigators of working groups, their frequency as PIs at the National Center for Ecological Analysis and Synthesis is now comparable to the national frequencies in biology and they are now equally qualified, in terms of their impact on the accumulation of ecological knowledge (as measured by the h-index. While women continue to be underrepresented as working group participants, peer-reviewed publications with gender-heterogeneous authorship teams received 34% more citations than publications produced by gender-uniform authorship teams. This suggests that peers citing these publications perceive publications that also happen to have gender-heterogeneous authorship teams as higher quality than publications with gender uniform authorship teams. Promoting diversity not only promotes representation and fairness but may lead to higher quality science.
Gender-heterogeneous working groups produce higher quality science.

Science.gov (United States)

Campbell, Lesley G; Mehtani, Siya; Dozier, Mary E; Rinehart, Janice

2013-01-01

Here we present the first empirical evidence to support the hypothesis that a gender-heterogeneous problem-solving team generally produced journal articles perceived to be higher quality by peers than a team comprised of highly-performing individuals of the same gender. Although women were historically underrepresented as principal investigators of working groups, their frequency as PIs at the National Center for Ecological Analysis and Synthesis is now comparable to the national frequencies in biology and they are now equally qualified, in terms of their impact on the accumulation of ecological knowledge (as measured by the h-index). While women continue to be underrepresented as working group participants, peer-reviewed publications with gender-heterogeneous authorship teams received 34% more citations than publications produced by gender-uniform authorship teams. This suggests that peers citing these publications perceive publications that also happen to have gender-heterogeneous authorship teams as higher quality than publications with gender uniform authorship teams. Promoting diversity not only promotes representation and fairness but may lead to higher quality science.
Mining Heterogeneous Information Networks by Exploring the Power of Links

Science.gov (United States)

Han, Jiawei

Knowledge is power but for interrelated data, knowledge is often hidden in massive links in heterogeneous information networks. We explore the power of links at mining heterogeneous information networks with several interesting tasks, including link-based object distinction, veracity analysis, multidimensional online analytical processing of heterogeneous information networks, and rank-based clustering. Some recent results of our research that explore the crucial information hidden in links will be introduced, including (1) Distinct for object distinction analysis, (2) TruthFinder for veracity analysis, (3) Infonet-OLAP for online analytical processing of information networks, and (4) RankClus for integrated ranking-based clustering. We also discuss some of our on-going studies in this direction.
Power quality assessment

International Nuclear Information System (INIS)

Fathi, H.M.E.

2012-01-01

The electrical power systems are exposed to different types of power quality disturbances problems. Assessment of power quality is necessary for maintaining accurate operation of sensitive equipment's especially for nuclear installations, it also ensures that unnecessary energy losses in a power system are kept at a minimum which lead to more profits. With advanced in technology growing of industrial / commercial facilities in many region. Power quality problems have been a major concern among engineers; particularly in an industrial environment, where there are many large-scale type of equipment. Thus, it would be useful to investigate and mitigate the power quality problems. Assessment of Power quality requires the identification of any anomalous behavior on a power system, which adversely affects the normal operation of electrical or electronic equipment. The choice of monitoring equipment in a survey is also important to ascertain a solution to these power quality problems. A power quality assessment involves gathering data resources; analyzing the data (with reference to power quality standards); then, if problems exist, recommendation of mitigation techniques must be considered. The main objective of the present work is to investigate and mitigate of power quality problems in nuclear installations. Normally electrical power is supplied to the installations via two sources to keep good reliability. Each source is designed to carry the full load. The Assessment of power quality was performed at the nuclear installations for both sources at different operation conditions. The thesis begins with a discussion of power quality definitions and the results of previous studies in power quality monitoring. The assessment determines that one source of electricity was deemed to have relatively good power quality; there were several disturbances, which exceeded the thresholds. Among of them are fifth harmonic, voltage swell, overvoltage and flicker. While the second
Power theories for improved power quality

CERN Document Server

Pasko, Marian

2012-01-01

Power quality describes a set of parameters of electric power and the load’s ability to function properly under specific conditions. It is estimated that problems relating to power quality costs the European industry hundreds of billions of Euros annually. In contrast, financing for the prevention of these problems amount to fragments of these costs. Power Theories for Improved Power Quality addresses this imbalance by presenting and assessing a range of methods and problems related to improving the quality of electric power supply. Focusing particularly on active compensators and the DSP based control algorithms, Power Theories for Improved Power Quality introduces the fundamental problems of electrical power. This introduction is followed by chapters which discuss: •‘Power theories’ including their historical development and application to practical problems, •operational principles of active compensator’s DSP control based algorithms using examples and results from laboratory research, and •t...
In-stream Physical Heterogeneity, Rainfall Aided Flushing, and Discharge on Stream Water Quality.

Science.gov (United States)

Gomes, Pattiyage I A; Wai, Onyx W H

2015-08-01

Implications of instream physical heterogeneity, rainfall-aided flushing, and stream discharge on water quality control have been investigated in a headwater stream of a climatic region that has contrasting dry and wet seasons. Dry (low flow) season's physical heterogeneity showed a positive correlation with good water quality. However, in the wet season, physical heterogeneity showed minor or no significance on water quality variations. Furthermore, physical heterogeneity appeared to be more complementary with good water quality subsequent to rainfall events. In many cases stream discharge was a reason for poor water quality. For the dry season, graywater inputs to the stream could be held responsible. In the wet season, it was probably the result of catchment level disturbances (e.g., regulation of ephemeral freshwater paths). Overall, this study revealed the importance of catchment-based approaches on water quality improvement in tandem with in-stream approaches framed on a temporal scale.
On the Dual-Decomposition-Based Resource and Power Allocation with Sleeping Strategy for Heterogeneous Networks

KAUST Repository

Alsharoa, Ahmad M.

2015-05-01

In this paper, the problem of radio and power resource management in long term evolution heterogeneous networks (LTE HetNets) is investigated. The goal is to minimize the total power consumption of the network while satisfying the user quality of service determined by each target data rate. We study the model where one macrocell base station is placed in the cell center, and multiple small cell base stations and femtocell access points are distributed around it. The dual decomposition technique is adopted to jointly optimize the power and carrier allocation in the downlink direction in addition to the selection of turned off small cell base stations. Our numerical results investigate the performance of the proposed scheme versus different system parameters and show an important saving in terms of total power consumption. © 2015 IEEE.
Discovery of Power-Law Growth in the Self-Renewal of Heterogeneous Glioma Stem Cell Populations.

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Michiya Sugimori

Full Text Available Accumulating evidence indicates that cancer stem cells (CSCs drive tumorigenesis. This suggests that CSCs should make ideal therapeutic targets. However, because CSC populations in tumors appear heterogeneous, it remains unclear how CSCs might be effectively targeted. To investigate the mechanisms by which CSC populations maintain heterogeneity during self-renewal, we established a glioma sphere (GS forming model, to generate a population in which glioma stem cells (GSCs become enriched. We hypothesized, based on the clonal evolution concept, that with each passage in culture, heterogeneous clonal sublines of GSs are generated that progressively show increased proliferative ability.To test this hypothesis, we determined whether, with each passage, glioma neurosphere culture generated from four different glioma cell lines become progressively proliferative (i.e., enriched in large spheres. Rather than monitoring self-renewal, we measured heterogeneity based on neurosphere clone sizes (#cells/clone. Log-log plots of distributions of clone sizes yielded a good fit (r>0.90 to a straight line (log(% total clones = k*log(#cells/clone indicating that the system follows a power-law (y = xk with a specific degree exponent (k = -1.42. Repeated passaging of the total GS population showed that the same power-law was maintained over six passages (CV = -1.01 to -1.17. Surprisingly, passage of either isolated small or large subclones generated fully heterogeneous populations that retained the original power-law-dependent heterogeneity. The anti-GSC agent Temozolomide, which is well known as a standard therapy for glioblastoma multiforme (GBM, suppressed the self-renewal of clones, but it never disrupted the power-law behavior of a GS population.Although the data above did not support the stated hypothesis, they did strongly suggest a novel mechanism that underlies CSC heterogeneity. They indicate that power-law growth governs the self-renewal of heterogeneous
Power Quality in DC Power Distribution Systems and Microgrids

Directory of Open Access Journals (Sweden)

Stephen Whaite

2015-05-01

Full Text Available This review paper discusses power quality considerations for direct current (DC electric power distribution systems, particularly DC microgrids. First, four selected sample DC architectures are discussed to provide motivation for the consideration of power quality in DC systems. Second, a brief overview of power quality challenges in conventional alternating current (AC distribution systems is given to establish the field of power quality. Finally, a survey of literature addressing power quality issues in DC systems is presented, and necessary power quality considerations in DC distribution system design and operation are discussed.
Management of speech and video telephony quality in heterogeneous wireless networks

CERN Document Server

Lewcio, Błażej

2014-01-01

This book shows how networking research and quality engineering can be combined to successfully manage the transmission quality when speech and video telephony is delivered in heterogeneous wireless networks. Nomadic use of services requires intelligent management of ongoing transmission, and to make the best of available resources many fundamental trade-offs must be considered. Network coverage versus throughput and reliability of a connection is one key aspect, efficiency versus robustness of signal compression is another. However, to successfully manage services, user-perceived Quality of Experience (QoE) in heterogeneous networks must be known, and the perception of quality changes must be understood. These issues are addressed in this book, in particular focusing on the perception of quality changes due to switching between diverse networks, speech and video codecs, and encoding bit rates during active calls.

Power quality in power systems and electrical machines

CERN Document Server

Fuchs, Ewald

2015-01-01

The second edition of this must-have reference covers power quality issues in four parts, including new discussions related to renewable energy systems. The first part of the book provides background on causes, effects, standards, and measurements of power quality and harmonics. Once the basics are established the authors move on to harmonic modeling of power systems, including components and apparatus (electric machines). The final part of the book is devoted to power quality mitigation approaches and devices, and the fourth part extends the analysis to power quality solutions for renewable
Design of Interline Unified Power Quality Conditioner for Power Quality Disturbances using Simulink

Science.gov (United States)

Kumaraswamy, G.; Reddy, Y. Rajasekhar; Harikrishna, Ch.

2012-10-01

Proliferation of electronic equipment in commercial and industrial processes has resulted in increasingly sensitive electrical loads to be fed from power distribution system which introduce contamination to voltage and current waveforms at the point of common coupling of industrial loads. The unified power quality conditioner (UPQC) is connected between two different feeders (lines), hence this method of connection of the UPQC is called as Interline UPQC (IUPQC).This paper proposes a new connection for a UPQC to improve the power quality of two feeders in a distribution system. Interline Unified Power Quality Conditioner (IUPQC), specifically aims at the integration of series VSC and Shunt VSC to provide high quality power supply by means of voltage sag/swell compensation, harmonic elimination and power factor correction in a power distribution network, so that improved power quality can be made available at the point of common coupling. The structure, control and capability of the IUPQC are discussed in this paper. The efficiency of the proposed configuration has been verified through simulation using MATLAB/ SIMULINK.
Energy Harvesting in Heterogeneous Networks with Hybrid Powered Communication Systems

KAUST Repository

Alsharoa, Ahmad; Celik, Abdulkadir; Kamal, Ahmed E.

2018-01-01

In this paper, we investigate an energy efficient and energy harvesting (EH) system model in heterogeneous networks (HetNets) where all base stations (BSS) are equipped to harvest energy from renewable energy sources. We consider a hybrid power
Power-Aware DVB-H Mobile TV System on Heterogeneous Multicore Platform

Directory of Open Access Journals (Sweden)

Chao Han-Chieh

2010-01-01

Full Text Available In mobile communication network, the mobile device integrated with TV player is a novel technology that provides TV program services to end users. As TV program is a real-time video service, it has greater technical difficulties to overcome than a traditional video file download or online streaming, especially when TV programs are played on handheld devices. A challenge is how to save power in order to provide users with longer TV program services. To address this issue, this study proposes a mobile TV system on a heterogeneous multicore platform, which utilizes a Digital Video Broadcasting-Handheld (DVB-H wireless network to receive the TV program signal, thus, saving power according to the features of DVB-H TV signal and heterogeneous multi-core.
Power Quality Issues on Wind Power Installations in Denmark

DEFF Research Database (Denmark)

Sørensen, Poul Ejnar; Cutululis, Nicolaos Antonio; Lund, Torsten

2007-01-01

offshore wind farms connected at transmission level. In this perspective, the power quality issues are divided into local issues particularly related to the voltage quality in the distribution systems and global issues related to the power system control and stability. Power quality characteristics of wind...
Parallelizing Compiler Framework and API for Power Reduction and Software Productivity of Real-Time Heterogeneous Multicores

Science.gov (United States)

Hayashi, Akihiro; Wada, Yasutaka; Watanabe, Takeshi; Sekiguchi, Takeshi; Mase, Masayoshi; Shirako, Jun; Kimura, Keiji; Kasahara, Hironori

Heterogeneous multicores have been attracting much attention to attain high performance keeping power consumption low in wide spread of areas. However, heterogeneous multicores force programmers very difficult programming. The long application program development period lowers product competitiveness. In order to overcome such a situation, this paper proposes a compilation framework which bridges a gap between programmers and heterogeneous multicores. In particular, this paper describes the compilation framework based on OSCAR compiler. It realizes coarse grain task parallel processing, data transfer using a DMA controller, power reduction control from user programs with DVFS and clock gating on various heterogeneous multicores from different vendors. This paper also evaluates processing performance and the power reduction by the proposed framework on a newly developed 15 core heterogeneous multicore chip named RP-X integrating 8 general purpose processor cores and 3 types of accelerator cores which was developed by Renesas Electronics, Hitachi, Tokyo Institute of Technology and Waseda University. The framework attains speedups up to 32x for an optical flow program with eight general purpose processor cores and four DRP(Dynamically Reconfigurable Processor) accelerator cores against sequential execution by a single processor core and 80% of power reduction for the real-time AAC encoding.
Selective pruning in pineapple plants as means to reduce heterogeneity in fruit quality

NARCIS (Netherlands)

Fassinou Hotegni, V.N.; Lommen, W.J.M.; Struik, P.C.; Agbossou, E.K.

2015-01-01

Heterogeneity in fruit quality (size and taste) is a major problem in pineapple production chains. The possibilities were investigated of reducing the heterogeneity in pineapple in the field by pruning slips on selected plants, in order to promote the fruit growth on these plants. Slips are side
Integration of heterogeneous industrial consumers to provide regulating power to the smart grid

DEFF Research Database (Denmark)

Rahnama, Samira; Stoustrup, Jakob; Rasmussen, Henrik

2013-01-01

In this paper, we propose a framework to utilize the flexibility of consumers in the future smart grid with a high share of fluctuating power. Focus is on industrial cases, where a total power consumption of a few number of consumers are large enough in order to bid in the market. Heterogeneous...
Power quality improvement of unbalanced power system with distributed generation units

DEFF Research Database (Denmark)

Hu, Y.; Chen, Zhe; Excell, P.

2011-01-01

This paper presents a power electronic system for improving the power quality of the unbalanced distributed generation units in three-phase four-wire system. In the system, small renewable power generation units, such as small PV generator, small wind turbines may be configured as single phase...... and control of the converter are described. Simulation results have demonstrated that the system can effectively correct the unbalance and enhance the system power quality....... generation units. The random nature of renewable power sources may result in significant unbalance in the power network and affect the power quality. An electronic converter system is proposed to correct the system unbalance and harmonics so as to deal with the power quality problems. The operation...
Power Quality Improvement by Unified Power Quality Conditioner Based on CSC Topology Using Synchronous Reference Frame Theory

Directory of Open Access Journals (Sweden)

Rajasekaran Dharmalingam

2014-01-01

Full Text Available This paper deals with the performance of unified power quality conditioner (UPQC based on current source converter (CSC topology. UPQC is used to mitigate the power quality problems like harmonics and sag. The shunt and series active filter performs the simultaneous elimination of current and voltage problems. The power fed is linked through common DC link and maintains constant real power exchange. The DC link is connected through the reactor. The real power supply is given by the photovoltaic system for the compensation of power quality problems. The reference current and voltage generation for shunt and series converter is based on phase locked loop and synchronous reference frame theory. The proposed UPQC-CSC design has superior performance for mitigating the power quality problems.
Power quality improvement by unified power quality conditioner based on CSC topology using synchronous reference frame theory.

Science.gov (United States)

Dharmalingam, Rajasekaran; Dash, Subhransu Sekhar; Senthilnathan, Karthikrajan; Mayilvaganan, Arun Bhaskar; Chinnamuthu, Subramani

2014-01-01

This paper deals with the performance of unified power quality conditioner (UPQC) based on current source converter (CSC) topology. UPQC is used to mitigate the power quality problems like harmonics and sag. The shunt and series active filter performs the simultaneous elimination of current and voltage problems. The power fed is linked through common DC link and maintains constant real power exchange. The DC link is connected through the reactor. The real power supply is given by the photovoltaic system for the compensation of power quality problems. The reference current and voltage generation for shunt and series converter is based on phase locked loop and synchronous reference frame theory. The proposed UPQC-CSC design has superior performance for mitigating the power quality problems.
Power Quality Improvement by Unified Power Quality Conditioner Based on CSC Topology Using Synchronous Reference Frame Theory

Science.gov (United States)

Dharmalingam, Rajasekaran; Dash, Subhransu Sekhar; Senthilnathan, Karthikrajan; Mayilvaganan, Arun Bhaskar; Chinnamuthu, Subramani

2014-01-01

This paper deals with the performance of unified power quality conditioner (UPQC) based on current source converter (CSC) topology. UPQC is used to mitigate the power quality problems like harmonics and sag. The shunt and series active filter performs the simultaneous elimination of current and voltage problems. The power fed is linked through common DC link and maintains constant real power exchange. The DC link is connected through the reactor. The real power supply is given by the photovoltaic system for the compensation of power quality problems. The reference current and voltage generation for shunt and series converter is based on phase locked loop and synchronous reference frame theory. The proposed UPQC-CSC design has superior performance for mitigating the power quality problems. PMID:25013854
Power quality issues current harmonics

CERN Document Server

Mikkili, Suresh

2015-01-01

Power Quality Issues: Current Harmonics provides solutions for the mitigation of power quality problems related to harmonics. Focusing on active power filters (APFs) due to their excellent harmonic and reactive power compensation in two-wire (single phase), three-wire (three-phase without neutral), and four-wire (three-phase with neutral) AC power networks with nonlinear loads, the text:Introduces the APF technology, describing various APF configurations and offering guidelines for the selection of APFs for specific application considerationsCompares shunt active filter (SHAF) control strategi
Custom power - the utility solution to distribution power quality

Energy Technology Data Exchange (ETDEWEB)

Woodley, N H [Westinghouse Electric Corp., Pittsburgh, PA (United States)

1997-04-01

The design of custom power products for electric power distribution system was discussed. Problems with power quality that result in loss of production to critical processes are costly and create a problem for the customer as well as the electric utility. Westinghouse has developed power quality improvement equipment for customers and utilities, using new technologies based on power electronics concepts. The Distribution Static Compensator (DSTATCOM) is a fast response, solid-state power controller that provides flexible voltage control for improving power quality at the point of connection to the utility`s 4.16 to 69 kV distribution feeder. STATCOM is a larger version of the DSTATCOM that can be used to solve voltage flicker problems caused by electric arc furnaces. Westinghouse has also developed a Dynamic Voltage Restorer (DVR) which protects a critical customer plant load from power system voltage disturbances. Solid-State Breakers (SSB) have also been developed which offer a solution to many of the distribution system problems that result in voltage sags, swells, and power outages. 6 refs., 8 figs.
A Metric and Workflow for Quality Control in the Analysis of Heterogeneity in Phenotypic Profiles and Screens

Science.gov (United States)

Gough, Albert; Shun, Tongying; Taylor, D. Lansing; Schurdak, Mark

2016-01-01

Heterogeneity is well recognized as a common property of cellular systems that impacts biomedical research and the development of therapeutics and diagnostics. Several studies have shown that analysis of heterogeneity: gives insight into mechanisms of action of perturbagens; can be used to predict optimal combination therapies; and to quantify heterogeneity in tumors where heterogeneity is believed to be associated with adaptation and resistance. Cytometry methods including high content screening (HCS), high throughput microscopy, flow cytometry, mass spec imaging and digital pathology capture cell level data for populations of cells. However it is often assumed that the population response is normally distributed and therefore that the average adequately describes the results. A deeper understanding of the results of the measurements and more effective comparison of perturbagen effects requires analysis that takes into account the distribution of the measurements, i.e. the heterogeneity. However, the reproducibility of heterogeneous data collected on different days, and in different plates/slides has not previously been evaluated. Here we show that conventional assay quality metrics alone are not adequate for quality control of the heterogeneity in the data. To address this need, we demonstrate the use of the Kolmogorov-Smirnov statistic as a metric for monitoring the reproducibility of heterogeneity in an SAR screen, describe a workflow for quality control in heterogeneity analysis. One major challenge in high throughput biology is the evaluation and interpretation of heterogeneity in thousands of samples, such as compounds in a cell-based screen. In this study we also demonstrate that three heterogeneity indices previously reported, capture the shapes of the distributions and provide a means to filter and browse big data sets of cellular distributions in order to compare and identify distributions of interest. These metrics and methods are presented as a
Cell heterogeneity problems in the analysis of zero power experiments

International Nuclear Information System (INIS)

Grimstone, M.J.; Stevenson, J.M.

1979-01-01

Methods are described for treating plate and pin cell heterogeneity in the preparation of broad group cross-sections used in the analysis of zero power fast reactor experiments. Methods used at Karlsruhe and Winfrith are summarised and compared, with particular reference to the treatment of resonance shielding, the calculation of broad group spatial fine structure, the treatment of leakage and the calculation of anisotropic diffusion coefficients. The problems of cells near boundaries such as core-breeder interfaces and of singularities such as control rods are also considered briefly. Numerical studies carried out to investigate approximations in the methods are described. These include tests of the accuracy of one-dimensional cell modelling techniques, and the validation by Monte Carlo of methods for treating streaming in the calculation of diffusion coefficients. Comparisons are shown between the heterogeneity effects calculated by the Karlsruhe and Winfrith methods for typical pin and plate cells used in the BIZET experimental programme, and their effect in a whole reactor calculation is indicated. Comparisons are given with measurements which provide tests of the heterogeneity calculations. These include reaction rate scans within pin and plate cells, and reaction rate measurements across sectors of pin and plate fuel, where the flux tilt is determined by the relative reactivity of the pin and plate cells. Finally, the heterogeneity problems arising in the interpretation of reaction rate measurements are discussed. (author)
Non-invasive quality evaluation of confluent cells by image-based orientation heterogeneity analysis.

Science.gov (United States)

Sasaki, Kei; Sasaki, Hiroto; Takahashi, Atsuki; Kang, Siu; Yuasa, Tetsuya; Kato, Ryuji

2016-02-01

In recent years, cell and tissue therapy in regenerative medicine have advanced rapidly towards commercialization. However, conventional invasive cell quality assessment is incompatible with direct evaluation of the cells produced for such therapies, especially in the case of regenerative medicine products. Our group has demonstrated the potential of quantitative assessment of cell quality, using information obtained from cell images, for non-invasive real-time evaluation of regenerative medicine products. However, image of cells in the confluent state are often difficult to evaluate, because accurate recognition of cells is technically difficult and the morphological features of confluent cells are non-characteristic. To overcome these challenges, we developed a new image-processing algorithm, heterogeneity of orientation (H-Orient) processing, to describe the heterogeneous density of cells in the confluent state. In this algorithm, we introduced a Hessian calculation that converts pixel intensity data to orientation data and a statistical profiling calculation that evaluates the heterogeneity of orientations within an image, generating novel parameters that yield a quantitative profile of an image. Using such parameters, we tested the algorithm's performance in discriminating different qualities of cellular images with three types of clinically important cell quality check (QC) models: remaining lifespan check (QC1), manipulation error check (QC2), and differentiation potential check (QC3). Our results show that our orientation analysis algorithm could predict with high accuracy the outcomes of all types of cellular quality checks (>84% average accuracy with cross-validation). Copyright © 2015 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.
Automated recognition system for power quality disturbances

Science.gov (United States)

Abdelgalil, Tarek

The application of deregulation policies in electric power systems has resulted in the necessity to quantify the quality of electric power. This fact highlights the need for a new monitoring strategy which is capable of tracking, detecting, classifying power quality disturbances, and then identifying the source of the disturbance. The objective of this work is to design an efficient and reliable power quality monitoring strategy that uses the advances in signal processing and pattern recognition to overcome the deficiencies that exist in power quality monitoring devices. The purposed monitoring strategy has two stages. The first stage is to detect, track, and classify any power quality violation by the use of on-line measurements. In the second stage, the source of the classified power quality disturbance must be identified. In the first stage, an adaptive linear combiner is used to detect power quality disturbances. Then, the Teager Energy Operator and Hilbert Transform are utilized for power quality event tracking. After the Fourier, Wavelet, and Walsh Transforms are employed for the feature extraction, two approaches are then exploited to classify the different power quality disturbances. The first approach depends on comparing the disturbance to be classified with a stored set of signatures for different power quality disturbances. The comparison is developed by using Hidden Markov Models and Dynamic Time Warping. The second approach depends on employing an inductive inference to generate the classification rules directly from the data. In the second stage of the new monitoring strategy, only the problem of identifying the location of the switched capacitor which initiates the transients is investigated. The Total Least Square-Estimation of Signal Parameters via Rotational Invariance Technique is adopted to estimate the amplitudes and frequencies of the various modes contained in the voltage signal measured at the facility entrance. After extracting the
On grid-connected power electronic systems: power quality improvement application

International Nuclear Information System (INIS)

Etxeberria-Otadui, I.

2003-09-01

The present PhD thesis deals with distribution grid-connected power electronic devices. The main focus has been power quality improvement with power electronic devices. The theoretical aspects and the power quality improvement techniques are presented and discussed. Power electronic devices are then presented, modelled and controlled. Original disturbance identification, power management and current/voltage control methods have been proposed, tested and analysed. A flexible test-bench, composed of a series and a shunt compensator, has been designed and built in order to test the studied control algorithms. These tests have permitted to experimentally evaluate and validate the proposed control algorithms and to make evident several problems that are not always visible on the theory. The conclusions outline the main short and mid term objectives and challenges in the field of power quality improvement devices. (author)
Power quality enhancement of renewable energy source power network using SMES system

International Nuclear Information System (INIS)

Seo, H.R.; Kim, A.R.; Park, M.; Yu, I.K.

2011-01-01

Power quality enhancement of a renewable energy source power network is performed by a real-toroidal-type SMES coil. SMES unit charges and discharges the HTS coil to mitigate the fluctuation of PV system output power. The grid connected PV and SMES system has been modeled and simulated using power-hard-in-the-loop simulation. The PHILS results demonstrated the effectiveness of the SMES system for enhancing power quality. This paper deals with power quality enhancement of renewable energy source power network using SMES system and describes the operation characteristics of HTS SMES system using real-toroidal-type SMES coil for smoothening the fluctuation of large-scale renewable energy source such as photovoltaic (PV) power generation system. It generates maximum power of PV array under various weather conditions. SMES unit charges and discharges the HTS coil to mitigate the fluctuation of PV system output power. The SMES unit is controlled according to the PV array output and the utility power quality conditions. The grid connected PV and SMES system has been modeled and simulated using power-hard-in-the-loop simulation (PHILS). The PHILS results demonstrated the effectiveness of the SMES system for enhancing power quality in power network including large-scale renewable energy source, especially PV power generation system.

Active power line conditioners design, simulation and implementation for improving power quality

CERN Document Server

Revuelta, Patricio Salmeron; Litrán, Salvador Pérez

2015-01-01

Active Power Line Conditioners: Design, Simulation and Implementation for Improving Power Quality presents a rigorous theoretical and practical approach to active power line conditioners, one of the subjects of most interest in the field of power quality. Its broad approach offers a journey that will allow power engineering professionals, researchers, and graduate students to learn more about the latest landmarks on the different APLC configurations for load active compensation. By introducing the issues and equipment needs that arise when correcting the lack of power quality in power grids
Power transformers quality assurance

CERN Document Server

Dasgupta, Indrajit

2009-01-01

About the Book: With the view to attain higher reliability in power system operation, the quality assurance in the field of distribution and power transformers has claimed growing attention. Besides new developments in the material technology and manufacturing processes of transformers, regular diagnostic testing and maintenance of any engineering product may be ascertained by ensuring: right selection of materials and components and their quality checks. application of correct manufacturing processes any systems engineering. the user`s awareness towards preventive maintenance. The
Digital image analysis of testicular and prostatic ultrasonographic echogencity and heterogeneity in dogs and the relation to semen quality.

Science.gov (United States)

Moxon, Rachel; Bright, Lucy; Pritchard, Beth; Bowen, I Mark; de Souza, Mírley Barbosa; da Silva, Lúcia Daniel Machado; England, Gary C W

2015-09-01

A semi-automated ultrasonographic method was developed to measure echogenicity and heterogeneity of the testes and prostate gland and relationships of these measures with semen quality were assessed in 43 fertile dogs. The relationship between animal age and body weight upon the volume of the testes, epididymal tail volume and prostate volume were also established. Mean testicular echogenicity was negatively correlated with the percentage of morphologically normal live spermatozoa (more echogenic testes were associated with fewer normal sperm) but not with any other semen quality measure. Mean testicular heterogeneity was positively correlated with the total spermatozoal output (more heterogenous testes, being those with anechoic parenchyma and prominent echogenic stippling, were associated with greater sperm output) but not with any other semen quality measure. There was no relationship between either mean prostatic echogenicity or mean prostatic heterogeneity and any semen quality measure. There was no relationship between age and any testicular or prostatic parameter; however bodyweight was significantly correlated with total testicular volume, total epididymal tail volume and total prostatic volume. Testicular and prostatic ultrasonographic echogenicity and heterogeneity can be objectively assessed using digital image analysis and testicular echogenicity and heterogeneity may be useful adjunct measurements in a breeding soundness examination. Copyright © 2015 Elsevier B.V. All rights reserved.
Spatial Heterogeneity of Water Quality in a Highly Degraded Tropical Freshwater Ecosystem

Science.gov (United States)

Zambrano, Luis; Contreras, Victoria; Mazari-Hiriart, Marisa; Zarco-Arista, Alba E.

2009-02-01

Awareness of environmental heterogeneity in ecosystems is critical for management and conservation. We used the Xochimilco freshwater system to describe the relationship between heterogeneity and human activities. This tropical aquatic ecosystem south of Mexico City is comprised of a network of interconnected canals and lakes that are influenced by agricultural and urban activities. Environmental heterogeneity was characterized by spatially extensive surveys within four regions of Xochimilco during rainy and dry seasons over 2 years. These surveys revealed a heterogeneous system that was shallow (1.1 m, SD = 0.4 ), warm (17°C, SD = 2.9), well oxygenated (5.0 mg l-1, SD = 3), turbid (45.7 NTU SD = 26.96), and extremely nutrient-rich (NO3-N = 15.9 mg l-1, SD=13.7; NH4-N = 2.88 mg l-1, SD = 4.24; and PO4-P = 8.3 mg l-1, SD = 2.4). Most of the variables were not significantly different between years, but did differ between seasons, suggesting a dynamic system within a span of a year but with a high resilience over longer periods of time. Maps were produced using interpolations to describe distributions of all variables. There was no correlation between individual variables and land use. Consequently, we searched for relationships using all variables together by generating a combined water quality index. Significant differences in the index were apparent among the four regions. Index values also differed within individual region and individual water bodies (e.g., within canals), indicating that Xochimilco has high local heterogeneity. Using this index on a map helped to relate water quality to human activities and provides a simple and clear tool for managers and policymakers.
Power quality enhancement at distribution level utilizing the unified power quality conditioner (UPQC)

Science.gov (United States)

Khadkikar, Vinod

The present doctoral work is based on the philosophy of optimal utilization of the available resources in a most effective and efficient way to improve the product efficiency and to reduce the overall cost. This work proposes a novel control philosophy termed as power angle control (PAC), in which both the series and shunt inverters share the load reactive power in co-ordination with each other without affecting the basic UPQC compensation capabilities. This eventually results in a better utilization of the series inverter, reduction in the shunt inverter rating to some extent and ultimately in the reduction of the overall cost of UPQC. Moreover, in this thesis work several other control approaches are also proposed, such as, unit vector template generation, quadrature voltage injection, generalized single-phase p-q theory and novel current unbalance compensation approach. All the developed concepts are successfully validated through digital simulation as well as extensive experimental investigations. Keywords. power quality, active power filter, unified power quality conditioner, reactive power compensation, harmonics compensation.
Power quality problems and mitigation techniques

CERN Document Server

Singh, Bhim; Al-Haddad, Kamal

2014-01-01

Maintaining a stable level of power quality in the distribution network is a growing challenge due to increased use of power electronics converters in domestic, commercial and industrial sectors. Power quality deterioration is manifested in increased losses; poor utilization of distribution systems; mal-operation of sensitive equipment and disturbances to nearby consumers, protective devices, and communication systems. However, as the energy-saving benefits will result in increased AC power processed through power electronics converters, there is a compelling need for improved understanding o
Effect of heterogeneities on the thermoelectric power of pressure vessel steel

International Nuclear Information System (INIS)

Simonet, L.

2006-12-01

In service working conditions, the vessel of the Pressurized Water Reactors (PWR) undergoes an ageing due to irradiation. In order to follow the evolution of the mechanical characteristics of the steel in service, EDF launched a surveillance program which consists to carry out mechanical tests on samples aged in reactor. However, the results of these tests have the disadvantage to be affected by the presence of heterogeneities within the steel. Indeed, because of its manufacturing process, the steel contains segregated areas. Thus, EDF launched Thermoelectric Power Measurements (TEP) on the resilience samples of the surveillance program, to complete the mechanical tests and to help with their interpretation. However, these measurements are today difficult to analyse because they include at the same time the effect of the irradiation and the effect of the metallurgical heterogeneities. The aim of this work consisted in evaluating the effect of the heterogeneities on the TEP of the non-irradiated vessel steel. For that, a numerical model was developed which allows to calculate the TEP of a composite structure. We have shown that the model is pertinent to highlight the effect of the heterogeneities on the TEP of the vessel steel, which is considered like a 'matrix'/'segregation' composite. The model allowed us to put emphasis on the influence of different parameters on the TEP measurement. We have thus showed that the measurements conditions have an important effect on the obtained TEP value (influence of the applied pressure, the position of the sample on the device, the site of the metallurgical heterogeneities,...). (author)
UPQC (Unified power Quality Conditioner)

Indian Academy of Sciences (India)

First page Back Continue Last page Graphics. UPQC (Unified power Quality Conditioner). Hybrid of Shunt and Series compensator. Compensate both Current Quality and Voltage Quality. Costlier Solution as it involves two set of Inverters.
Power Quality Improvements in Wind Diesel Power Generation System

Directory of Open Access Journals (Sweden)

Omar Feddaoui

2015-08-01

Full Text Available Generation of electricity using diesel is costly for small remote isolated communities. At remote location electricity generation from renewable energy such as wind can help reduce the overall operating costs by reducing the fuel costs. However, the penetration of wind power into small diesel-based grids is limited because of its effect on power quality and reliability. This paper focuses on the combination of Wind Turbine and Diesel Generator systems for sustained power generation, to improve the power quality of wind generation system. The performances of the optimal control structure are assessed and discussed by means of a set of simulations.
Heterogeneous gas core reactor

International Nuclear Information System (INIS)

Han, K.I.

1977-01-01

Preliminary investigations of a heterogeneous gas core reactor (HGCR) concept suggest that this potential power reactor offers distinct advantages over other existing or conceptual reactor power plants. One of the most favorable features of the HGCR is the flexibility of the power producing system which allows it to be efficiently designed to conform to a desired optimum condition without major conceptual changes. The arrangement of bundles of moderator/coolant channels in a fissionable gas or mixture of gases makes a truly heterogeneous nuclear reactor core. It is this full heterogeneity for a gas-fueled reactor core which accounts for the novelty of the heterogeneous gas core reactor concept and leads to noted significant advantages over previous gas core systems with respect to neutron and fuel economy, power density, and heat transfer characteristics. The purpose of this work is to provide an insight into the design, operating characteristics, and safety of a heterogeneous gas core reactor system. The studies consist mainly of neutronic, energetic and kinetic analyses of the power producing and conversion systems as a preliminary assessment of the heterogeneous gas core reactor concept and basic design. The results of the conducted research indicate a high potential for the heterogeneous gas core reactor system as an electrical power generating unit (either large or small), with an overall efficiency as high as 40 to 45%. The HGCR system is found to be stable and safe, under the conditions imposed upon the analyses conducted in this work, due to the inherent safety of ann expanding gaseous fuel and the intrinsic feedback effects of the gas and water coolant
Why Panel Tests of Purchasing Power Parity Should Allow for Heterogeneous Mean Reversion

NARCIS (Netherlands)

C.G. Koedijk (Kees); B. Tims (Ben); M.A. van Dijk (Mathijs)

2010-01-01

textabstractAbstract Recent studies of purchasing power parity (PPP) use panel tests that fail to take into account heterogeneity in the speed of mean reversion across real exchange rates. In contrast to several other severe restrictions of panel models and tests of PPP, the assumption of
Optimization for Customized Power Quality Service in Multibus Microgrids

DEFF Research Database (Denmark)

Meng, Lexuan; Guerrero, Josep M.

2017-01-01

Power quality requirements for different consumers and electric equipment are distinctive. Conventionally, common power quality standards are applied to the whole power grid inducing debate between technical commissions. Customized power quality standards for different consumers become a widely...... accepted solution. The main challenge is on the proper regulation of power quality in different areas. This paper considers a multibus microgrid system, where the power quality in each area has individual adjustable standard. Voltage unbalance, induced by connection of single-phase loads, is taken...
Optimum power quality service in multi-bus microgrid systems

DEFF Research Database (Denmark)

Meng, Lexuan; Guerrero, Josep M.

2017-01-01

Power quality requirements for different consumers and electric equipment are distinguished. Conventionally a common power quality standard is applied to the whole power grid inducing debate between several sides, including consumers, generation sites and technical commissions. Customized power...... quality standard settings for different consumers become a widely accepted solution. The main challenge is on the proper regulation of power quality in different areas. This paper considers a multi-bus microgrid system where the power quality in each has flexible and individual standard. Distributed...... generators are utilized to provide power quality regulation functions. An optimization method based strategy is proposed and implemented with the power converter control system. A general mathematical model is established which can be used in the optimization problem for evaluating the objective function...
Assessment of Power Quality Problems for TRIGA PUSPATI Reactor (RTP)

International Nuclear Information System (INIS)

Mohd Fazli Zakaria; Ramachandaramurthy, V.K.

2016-01-01

The electrical power systems are exposed to different types of power quality disturbances. Investigation and monitoring of power quality is necessary to maintain accurate operation of sensitive equipment especially for nuclear installations. This paper will discuss the power quality problems observed at the electrical sources of PUSPATI TRIGA Reactor (RTP). Assessment of power quality requires the identification of any anomalous behavior on a power system, which adversely affects the normal operation of electrical or electronic equipment. A power quality assessment involves gathering data resources; analyzing the data (with reference to power quality standards) then, if problems exist, recommendation of mitigation techniques must be considered. Field power quality data is collected by power quality recorder and analyzed with reference to power quality standards. Normally the electrical power is supplied to the RTP via two sources in order to keep a good reliability where each of them is designed to carry the full load. The assessment of power quality during reactor operation was performed for both electrical sources. There were several disturbances such as voltage harmonics and flicker that exceeded the thresholds. (author)
Effect of Heterogeneity of JSFR Fuel Assemblies to Power Distribution

International Nuclear Information System (INIS)

Takeda, Toshikazu; Shimazu, Yoichiro; Hibi, Koki; Fujimura, Koji

2013-01-01

Conclusion: 1) Strong heterogeneity of JSFR assemblies was successfully calculated by BACH. 2) Verification test of BACH: • Infinite assembly model; • Color set model; • Good agreement with Monte-Carlo results. 3) Core calculations 3 models for inner duct was used; inward model, outward model and homogeneous model. • k eff difference between the inward and out ward model → 0.3%Δk; • ~20% effect on flux and power distributions. Therefore, we have to pay careful attention for the location of inner duct in fuel loading of JSFR
A Comparison of Power Quality Controllers

Directory of Open Access Journals (Sweden)

Petr Černek

2012-01-01

Full Text Available This paper focuses on certain types of FACTS (Flexibile AC Transmission System controllers, which can be used for improving the power quality at the point of connection with the power network. It focuses on types of controllers that are suitable for use in large buildings, rather than in transmission networks. The goal is to compare the features of the controllers in specific tasks, and to clarify which solution is best for a specific purpose. It is in some cases better and cheaper to use a combination of controllers than a single controller. The paper also presents the features of a shunt active harmonic compensator, which is a very modern power quality controller that can be used in many cases, or in combination with other controllers. The comparison was made using a matrix diagram that, resulted from mind mapsand other analysis tools. The paper should help engineers to choose the best solution for improving the power quality in a specific power network at distribution level.
Improving Power Quality in AC Supply Grids

Directory of Open Access Journals (Sweden)

Piotr Fabijański

2015-12-01

Full Text Available This paper describes a digital and actual model of the UPQC (Unified Power Quality Conditioner integrated system for power quality improvement. The UPQC’s design and its connection to an AC supply grid, 1-phase and 3-phase alike, provide effective compensation of unwanted interferences in the waveforms of load supply voltages and non-linear load currents. This article presents an overview of topologies and control strategies. The study of the UPQC confirmed its positive impact on the power quality. The electricity parameters were significantly improved. Total harmonic distortion in supply voltage THDu decreased six-fold to 1.89%, and total harmonic distortion in load current THDi decreased more than ten-fold to 2.38% for a non-linear load (uncontrolled bridge rectifier with load L. Additionally, symmetrisation of supply voltages and reactive power compensation Q of linear load was obtained. The UPQC integrated system for power quality improvement can be used wherever high-quality and PN-EN 50160 standard – compliant electricity is required.
Power quality load management for large spacecraft electrical power systems

Science.gov (United States)

Lollar, Louis F.

1988-01-01

In December, 1986, a Center Director's Discretionary Fund (CDDF) proposal was granted to study power system control techniques in large space electrical power systems. Presented are the accomplishments in the area of power system control by power quality load management. In addition, information concerning the distortion problems in a 20 kHz ac power system is presented.
An Optimal Joint User Association and Power Allocation Algorithm for Secrecy Information Transmission in Heterogeneous Networks

Directory of Open Access Journals (Sweden)

Rong Chai

2017-01-01

Full Text Available In recent years, heterogeneous radio access technologies have experienced rapid development and gradually achieved effective coordination and integration, resulting in heterogeneous networks (HetNets. In this paper, we consider the downlink secure transmission of HetNets where the information transmission from base stations (BSs to legitimate users is subject to the interception of eavesdroppers. In particular, we stress the problem of joint user association and power allocation of the BSs. To achieve data transmission in a secure and energy efficient manner, we introduce the concept of secrecy energy efficiency which is defined as the ratio of the secrecy transmission rate and power consumption of the BSs and formulate the problem of joint user association and power allocation as an optimization problem which maximizes the joint secrecy energy efficiency of all the BSs under the power constraint of the BSs and the minimum data rate constraint of user equipment (UE. By equivalently transforming the optimization problem into two subproblems, that is, power allocation subproblem and user association subproblem of the BSs, and applying iterative method and Kuhn-Munkres (K-M algorithm to solve the two subproblems, respectively, the optimal user association and power allocation strategies can be obtained. Numerical results demonstrate that the proposed algorithm outperforms previously proposed algorithms.
Quality assurance program for nuclear power plants

International Nuclear Information System (INIS)

Gamon, T.H.

1976-02-01

The Topical Report presented establishes and provides the basis for the Brown and Root Quality Assurance Program for Nuclear Power Plants from which the Brown and Root Quality Assurance Manual is prepared and implemented. The Quality Assurance Program is implemented by the Brown and Root Power Division during the design, procurement, and construction phases of nuclear power plants. The Brown and Root Quality Assurance Program conforms to the requirements of Nuclear Regulatory Commission Regulation 10 CFR 50, Appendix B; to approved industry standards such as ANSI N45.2 and ''Daughter Standards''; or to equivalent alternatives as indicated in the appropriate sections of the report

Quality assurance program for nuclear power plants

International Nuclear Information System (INIS)

Gamon, T.H.

1976-06-01

This topical report establishes and provides the basis for the Brown and Root Quality Assurance Program for Nuclear Power Plants from which the Brown and Root Quality Assurance Manual is prepared and implemented. The Quality Assurance Program is implemented by the Brown and Root Power Division during the design, procurement, and construction phases of nuclear power plants. The Brown and Root Quality Assurance Program conforms to the requirements of Nuclear Regulatory Commission Regulation 10 CFR 50, Appendix B; to approved industry standards such as ANSI N45.2 and ''Daughter Standards''; or to equivalent alternatives as indicated in the appropriate sections of this report
Distributed power quality improvement in residential microgrids

DEFF Research Database (Denmark)

Naderi Zarnaghi, Yahya; Hosseini, Seyed Hossein; Ghassem Zadeh, Saeid

2017-01-01

The importance of power quality issue on micro grids and also the changing nature of power system distortions will lead the future power systems to use distributed power quality improvement (DPQI) devices. One possible choice of these DPQIs are multifunctional DGs that could compensate some...... harmonics in the location of generation and prevent the harmonics to enter main power grid. In this paper a control method based on virtual harmonic impedance is presented for these multifunctional DGs and the effect of the location of these DGs on compensation procedure is studied with simulating...
Quality assurance/quality control, reliability and availability of nuclear power plants

International Nuclear Information System (INIS)

Kueffer, K.

1981-01-01

In a first part this lectures will present a survey on nuclear power production and plant performance in the Western World and discuss key parameters such as load factors and non-availability. Some main reasons for reliable performance of nuclear power plants are given. The second part of this lecture deals with the question how quality assurance and quality control measures do directly influence plant reliability, availability and, thus, economy. Derived from worldwide experience gained from operating nuclear power plants, it may be concluded that the implementation of an overall quality assurance programme does not only satisfy safety requirements set forth by the nuclear regulatory bodies, but has also a considerable impact on plant reliability and availability. A positive effect on these figures will be achieved if the established quality assurance programme provides for a coordinated approach to all activities affecting quality. It is discussed how the quality of a product should be controlled and what kind of quality assurance measures by performed examples are given to demonstrate that the expenditure for maintenance work on components will decrease if planned and systematic quality assurance actions have been implemented during all procurement stages. (orig./RW)
Nuclear power plants - Quality assurance

International Nuclear Information System (INIS)

1980-01-01

This International Standard defines principles for the establishment and implementation of quality assurance programmes during all phases of design, procurement, fabrication, construction, commissioning, operation, maintenance and decommissioning of structures, systems and components of nuclear power plants. These principles apply to activities affecting the quality of items, such as designing, purchasing, fabricating, handling, shipping, storing, cleaning, erecting, installing, testing, commissioning, operating, inspecting, maintaining, repairing, refuelling and modifying and eventually decommissioning. The manner in which the principles described in this document will be implemented in different organizations involved in a specific nuclear power project will depend on regulatory and contractual requirements, the form of management applied to a nuclear power project, and the nature and scope of the work to be performed by different organizations
Heterogeneous sharpness for cross-spectral face recognition

Science.gov (United States)

Cao, Zhicheng; Schmid, Natalia A.

2017-05-01

Matching images acquired in different electromagnetic bands remains a challenging problem. An example of this type of comparison is matching active or passive infrared (IR) against a gallery of visible face images, known as cross-spectral face recognition. Among many unsolved issues is the one of quality disparity of the heterogeneous images. Images acquired in different spectral bands are of unequal image quality due to distinct imaging mechanism, standoff distances, or imaging environment, etc. To reduce the effect of quality disparity on the recognition performance, one can manipulate images to either improve the quality of poor-quality images or to degrade the high-quality images to the level of the quality of their heterogeneous counterparts. To estimate the level of discrepancy in quality of two heterogeneous images a quality metric such as image sharpness is needed. It provides a guidance in how much quality improvement or degradation is appropriate. In this work we consider sharpness as a relative measure of heterogeneous image quality. We propose a generalized definition of sharpness by first achieving image quality parity and then finding and building a relationship between the image quality of two heterogeneous images. Therefore, the new sharpness metric is named heterogeneous sharpness. Image quality parity is achieved by experimentally finding the optimal cross-spectral face recognition performance where quality of the heterogeneous images is varied using a Gaussian smoothing function with different standard deviation. This relationship is established using two models; one of them involves a regression model and the other involves a neural network. To train, test and validate the model, we use composite operators developed in our lab to extract features from heterogeneous face images and use the sharpness metric to evaluate the face image quality within each band. Images from three different spectral bands visible light, near infrared, and short
Quality management in nuclear power plant technology

International Nuclear Information System (INIS)

Brosche, D.; Ehrnsperger, K.

2001-01-01

Quality assurance and therefore quality management are essential preconditions for the safety and availability of nuclear power plants. On the basis of the rules of the Kerntechnischer Ausschuss KTA 1401 the quality management in the former Bayernwerk AG and the Bayernwerk Kernenergie GmbH as well as in the Arbeitsgemeinschaft Auftragnehmerbeurteilung within the VGB Technical Association of Large Power Plant Operators is described. (orig.) [de
Improving wind power quality with energy storage

DEFF Research Database (Denmark)

Rasmussen, Claus Nygaard

2009-01-01

The results of simulation of the influence of energy storage on wind power quality are presented. Simulations are done using a mathematical model of energy storage. Results show the relation between storage power and energy, and the obtained increase in minimum available power from the combination...... of wind and storage. The introduction of storage enables smoothening of wind power on a timescale proportional to the storage energy. Storage does not provide availability of wind power at all times, but allows for a certain fraction of average power in a given timeframe to be available with high...... probability. The amount of storage capacity necessary for significant wind power quality improvement in a given period is found to be 20 to 40% of the energy produced in that period. The necessary power is found to be 80 to 100% of the average power of the period....
Power quality of small rural industries

International Nuclear Information System (INIS)

Koval, D.O.; Leonard, J.J.; Licsko, Z.J.

1991-01-01

Successful and economical operation of small rural industries (e.g., grain, dairy, irrigation, pig, poultry, beef feedlots, etc.) is a fundamental objective of society. However, when the performance and life expectancy of industrial electronic and electrical equipment is significantly affected by power supply anomalies caused by polluting loads at an industrial site and by utility normal operational activities, the economic benefits of this technology are quickly eradicated. This paper will present the results of a detailed power quality survey of 23 small rural industries sponsored by the Canadian Electrical Association and provides a knowledge base on rural power quality and the possible origins of power supply problems experienced at the various industrial sites. The results of the survey provide a basis for mitigating actions by the utilities and their rural industrial customers to design and operate their electrical systems to minimize the effects of power supply anomalies
Quality surveillance at nuclear power plants

International Nuclear Information System (INIS)

Deviney, D.E.

1990-01-01

Quality surveillance (QS) of nuclear power plants has been occurring for a number of years and is growing in importance as a management tool for assuring that power plants are operated and maintained safely. Quality surveillance can be identified by many terms, such as monitoring, assessment, technical audits, and others. The name given to the function is not important. Quality surveillance at nuclear power plants developed out of a need. Historically, audits were performed to verify compliance to quality program requirements. Verification of day-to-day implementation of activities was not being performed. This left a void in verification activities since inspections were mainly directed at hardware verification. Quality surveillance, therefore, was born out of a need to fill this void in verification. This paper discusses quality surveillance definition; objectives of QS, activities considered for QS, personnel performing QS. As in any human endeavor, people and the attitudes of those people make a program succeed or fail. In the case of QS this is even more critical because of the overview and exposure given to the nuclear industry. Properly trained and experienced personnel performing QS combined with the right attitude contribute to the successful performance of a QS. This is only one side of the success equation, however; acceptance of and actions taken by plant management establish the total success of a QS program
Isolated Power Generation System Using Permanent Magnet Synchronous Generator with Improved Power Quality

Science.gov (United States)

Arya, Sabha Raj; Patel, Ashish; Giri, Ashutosh

2018-03-01

This paper deals wind energy based power generation system using Permanent Magnet Synchronous Generator (PMSG). It is controlled using advanced enhanced phase-lock loop for power quality features using distribution static compensator to eliminate the harmonics and to provide KVAR compensation as well as load balancing. It also manages rated potential at the point of common interface under linear and non-linear loads. In order to have better efficiency and reliable operation of PMSG driven by wind turbine, it is necessary to analyze the governing equation of wind based turbine and PMSG under fixed and variable wind speed. For handling power quality problems, power electronics based shunt connected custom power device is used in three wire system. The simulations in MATLAB/Simulink environment have been carried out in order to demonstrate this model and control approach used for the power quality enhancement. The performance results show the adequate performance of PMSG based power generation system and control algorithm.
Quality assurance during operation of nuclear power plants

International Nuclear Information System (INIS)

1994-01-01

The general requirements applicable to the quality assurance of the Finnish nuclear power plants are presented in the Council of State Decision (395/91) and in the guide YVL 1.4. This guide specifies the quality assurance requirements to be applied during the operation of the nuclear power plants as well as of the other nuclear facilities. Quality assurance applies to all the activities and organizations with a bearing on the safe operation of the nuclear power plants. (5 refs.)
Advances in nonmarket valuation econometrics: Spatial heterogeneity in hedonic pricing models and preference heterogeneity in stated preference models

Science.gov (United States)

Yoo, Jin Woo

In my 1st essay, the study explores Pennsylvania residents. willingness to pay for development of renewable energy technologies such as solar power, wind power, biomass electricity, and other renewable energy using a choice experiment method. Principle component analysis identified 3 independent attitude components that affect the variation of preference, a desire for renewable energy and environmental quality and concern over cost. The results show that urban residents have a higher desire for environmental quality and concern less about cost than rural residents and consequently have a higher willingness to pay to increase renewable energy production. The results of sub-sample analysis show that a representative respondent in rural (urban) Pennsylvania is willing to pay 3.8(5.9) and 4.1(5.7)/month for increasing the share of Pennsylvania electricity generated from wind power and other renewable energy by 1 percent point, respectively. Mean WTP for solar and biomass electricity was not significantly different from zero. In my second essay, heterogeneity of individual WTP for various renewable energy technologies is investigated using several different variants of the multinomial logit model: a simple MNL with interaction terms, a latent class choice model, a random parameter mixed logit choice model, and a random parameter-latent class choice model. The results of all models consistently show that respondents. preference for individual renewable technology is heterogeneous, but the degree of heterogeneity differs for different renewable technologies. In general, the random parameter logit model with interactions and a hybrid random parameter logit-latent class model fit better than other models and better capture respondents. heterogeneity of preference for renewable energy. The impact of the land under agricultural conservation easement (ACE) contract on the values of nearby residential properties is investigated using housing sales data in two Pennsylvania
Power quality research techniques: advantages and disadvantages

International Nuclear Information System (INIS)

Gil Montoya, Francisco; Manzano Agugliaro, Francisco; Gomez Lopez, Julio; Sanchez Alguacil, Pedro

2012-01-01

Nowadays, power quality (PQ) plays a very important role in power systems. So that is why it is very important to use suitable tools allowing a precise detection of anomalies and perturbations in power systems. Given traditional analysis techniques, such as Fourier Transform, today new tools are being developed based on domain transformation, such as Wavelet Transform (WT) or S-Transform (ST), along with Artificial Intelligence (AI) techniques such as Fuzzy Logic (FL) or Artificial Neural Networks (ANN). In this paper, new algorithm and mathematic techniques are reviewed and discussed, and also compared with traditional techniques, revealing the precision and superiority achieved with these new techniques. ST and WT is detailed, basically, as a tool with great scope and future in power quality analysis because of its precision, noise immunity and its contribution with quality information about PQ.
The common denominator between DSM and power quality

International Nuclear Information System (INIS)

Porter, G.

1993-01-01

As utilities implement programs to push for energy efficiency, one of the results may be an increased population of end-uses that have a propensity to be sensitive to power delivery abnormalities. Some may view this as the price we have to pay for increasing the functionality of bulk 60 Hz power. Others may view this as a good reason to stay away from DSM. The utility industry must view this situation as an important element of their DSM planning and reflect the costs of mitigating potential power quality problems in the overall program. Power quality mitigation costs will not drastically add much to the total DSM bill, but the costs of poor power quality could definitely negate the positive benefits of new technologies. Failure to properly plan for the sensitivities of energy efficient equipment will be a major mistake considering the solutions are fairly well known. Proper understanding, education, design, and protection, using a systems approach to problem solving, will ensure that power quality problems won't force us to abandon beneficial efficiency improvement programs
Solution of electric power quality problems by troika cooperation

International Nuclear Information System (INIS)

Khan, N.; Ahmad, M.I.

1999-01-01

Power quality is a growing concern effecting utility supply continuity, sensitivity customer productivity and manufacturer equipment. Power quality problems such as voltage sags, swells, distortions and transient surges caused by short circuit faults or motor starting, switching reactive loads or phase to ground faults. VSD or arcing loads and inductive or capacity load switching may result in process shutdown or contactor dropout, under voltage tripping and speed drift or ASD tripping. This work describes results of a power quality study concluding urgent need for enhancing cooperation between utilities, customers and manufactures to improve power quality problems. Individual responsibilities of utilities personnel, sensitive equipment customers and power equipment manufacturers in light of available power conditioning technology, regarding deployment of equipment and improvement of design strategies have been discussed for precious end users. (authors)
Effect of power quality on windings temperature of marine induction motors

Energy Technology Data Exchange (ETDEWEB)

Gnacinski, P. [Gdynia Maritime University, Department of Ship Electrical Power Engineering, Morska Str. 83, 81-225 Gdynia (Poland)], E-mail: piotrg@am.gdynia.pl

2009-10-15

Marine induction machines are exposed to various power quality disturbances appearing simultaneously in ship power systems: frequency and voltage rms value deviation, voltage unbalance and voltage waveform distortions. As a result, marine induction motors can be seriously overheated due to lowered supply voltage quality. Improvement of the protection of marine induction machines requires an appropriate method of power quality assessment and modification of the power quality regulations of ship classification societies. This paper presents an analytical model of an induction cage machine supplied with voltage of lowered quality, used in part II of the work (effect of power quality on windings temperature of marine induction motors. Part II. Results of investigations and recommendations for related regulations) for power quality assessment in ship power systems, and for justification of the new power quality regulations proposal. The presented model is suitable for implementation in an on-line measurement system.
Quality management for nuclear power plants in Germany. Track 1

International Nuclear Information System (INIS)

Dieter, Brosche; Ehrnsperger, K.

2001-01-01

An essential requirement for the safety of nuclear power plants is the quality assurance which for example is fixed also in the German safety criteria for nuclear power plants as the first principle of prime importance and also fixed in the technical rules for nuclear power plants. Quality assurance must be performed in all phases of the lifetime of a nuclear power plant and also all partners for example suppliers, operators, experts and authorities are involved in the quality assurance process. All activities in connection with quality assurance are summarized in an integrated quality assurance system or quality assurance management. (author)
Investigation And Mitigation Techniques Of Power Quality Problems In Nuclear Installations

International Nuclear Information System (INIS)

Ayad, N.; Elsherbiny, E.; Eleissawi, H.; Zaher, M.; AbdelSalam, G.

2013-01-01

The electrical power systems are exposed to different types of power quality disturbances problems. Investigation and monitoring of power quality is necessary to maintain accurate operation of sensitive equipment especially for nuclear installations. The present research discusses investigation and monitoring of power quality problems for the electrical sources of nuclear installations. Field power quality data is collected by power analyzer and analyzed with reference to power quality standards. There were several disturbances exceeded the thresholds, they were voltage harmonics and voltage flicker. Mitigation techniques were suggested to install a passive filter at low voltage side and all sensitive and critical loads should be isolated and fed through uninterruptible power supply (UPS)
A heterogeneous multi-core platform for low power signal processing in systems-on-chip

DEFF Research Database (Denmark)

Paker, Ozgun; Sparsø, Jens; Haandbæk, Niels

2002-01-01

is based on message passing. The mini-cores are designed as parameterized soft macros intended for a synthesis based design flow. A 520.000 transistor 0.25µm CMOS prototype chip containing 6 mini-cores has been fabricated and tested. Its power consumption is only 50% higher than a hardwired ASIC and more......This paper presents a low-power and programmable DSP architecture - a heterogeneous multiprocessor platform consisting of standard CPU/DSP cores, and a set of simple instruction set processors called mini-cores each optimized for a particular class of algorithm (FIR, IIR, LMS, etc.). Communication...
The failure rate dynamics in heterogeneous populations

International Nuclear Information System (INIS)

Cha, Ji Hwan; Finkelstein, Maxim

2013-01-01

Most populations encountered in real world are heterogeneous. In reliability applications, the mixture (observed) failure rate, obviously, can be considered as a measure of ‘average’ quality in these populations. However, in addition to this average measure, some variability characteristics for failure rates can be very helpful in describing the time-dependent changes in quality of heterogeneous populations. In this paper, we discuss variance and the coefficient of variation of the corresponding random failure rate as variability measures for items in heterogeneous populations. Furthermore, there is often a risk that items of poor quality are selected for important missions. Therefore, along with the ‘average quality’ of a population, more ‘conservative’ quality measures should be also defined and studied. For this purpose, we propose the percentile and the tail-mixture of the failure rates as the corresponding conservative measures. Some illustrative examples are given. -- Highlights: ► This paper provides the insight on the variability measures in heterogeneous populations. ► The conservative quality measures in heterogeneous populations are defined. ► The utility of these measures is illustrated by meaningful examples. ► This paper provides a better understanding of the dynamics in heterogeneous populations

A method to calculate the effect of heterogeneous composition on bundle power

Energy Technology Data Exchange (ETDEWEB)

Choi, Hang Bok [Korea Atomic Energy Research Institute, Taejon (Korea)

1998-09-01

In the DUPIC fuel cycle, the spent pressurized water reactor (PWR) fuel is used in a Canada deuterium uranium (CANDU) reactor. Depending on the initial condition and burnup history of PWR fuel, the DUPIC fuel composition varies accordingly. In order to see the effect of the fuel composition, a simple and fast method was developed and applied to the DUPIC fuel. This report discusses the method developed to predict the effect of heterogeneous fuel composition on the bundle power. (author). 3 refs., 5 tabs.
An evaluation method of power quality about electrified railways connected to power grid based on PSCAD/EMTDC

Science.gov (United States)

Liang, Weibin; Ouyang, Sen; Huang, Xiang; Su, Weijian

2017-05-01

The existing modeling process of power quality about electrified railways connected to power grid is complicated and the simulation scene is incomplete, so this paper puts forward a novel evaluation method of power quality based on PSCAD/ETMDC. Firstly, a model of power quality about electrified railways connected to power grid is established, which is based on testing report or measured data. The equivalent model of electrified locomotive contains power characteristic and harmonic characteristic, which are substituted by load and harmonic source. Secondly, in order to make evaluation more complete, an analysis scheme has been put forward. The scheme uses a combination of three-dimensions of electrified locomotive, which contains types, working conditions and quantity. At last, Shenmao Railway is taken as example to evaluate the power quality at different scenes, and the result shows electrified railways connected to power grid have significant effect on power quality.
Inverted Unified Power Quality Conditioner to compensate overvoltage

Directory of Open Access Journals (Sweden)

Yeison Alberto Garcés Gómez

2017-07-01

Full Text Available Introduction: The use of unified power quality conditioners UPQC in the electric systems can correct waveform distortions in a steady state, like harmonics, flicker, and the power factor. Objective: This paper presents a novel approach for active compensation of overvoltage with a UPQC in dual topology or iUPQC. Methodology: The study it is presented in five stages, the section I shows an introduction and the state of the art, section II presents the unified power quality conditioner UPQC, section III describes the generalized reactive power theory applied to the iUPQC (dual topology, section IV shows the numerical simulations and the results and section V presents the conclusions of the study. Results: The results for the application of the iUPQC to the compensation of overvoltage are proved and compared with the more representative theory related to compensation of harmonics and low power factor. Conclusions: The control algorithm presented for the unified power quality conditioner in dual topology allows to compensate the overvoltage in three-phase systems as well as voltage and current harmonics and the low power factor.
Assessment and mitigation of power quality problems for PUSPATI TRIGA Reactor (RTP)

Science.gov (United States)

Zakaria, Mohd Fazli; Ramachandaramurthy, Vigna K.

2017-01-01

An electrical power systems are exposed to different types of power quality disturbances. Investigation and monitoring of power quality are necessary to maintain accurate operation of sensitive equipment especially for nuclear installations. This paper will discuss the power quality problems observed at the electrical sources of PUSPATI TRIGA Reactor (RTP). Assessment of power quality requires the identification of any anomalous behavior on a power system, which adversely affects the normal operation of electrical or electronic equipment. A power quality assessment involves gathering data resources; analyzing the data (with reference to power quality standards) then, if problems exist, recommendation of mitigation techniques must be considered. Field power quality data is collected by power quality recorder and analyzed with reference to power quality standards. Normally the electrical power is supplied to the RTP via two sources in order to keep a good reliability where each of them is designed to carry the full load. The assessment of power quality during reactor operation was performed for both electrical sources. There were several disturbances such as voltage harmonics and flicker that exceeded the thresholds. To reduce these disturbances, mitigation techniques have been proposed, such as to install passive harmonic filters to reduce harmonic distortion, dynamic voltage restorer (DVR) to reduce voltage disturbances and isolate all sensitive and critical loads.
Monitoring and analyzing features of electrical power quality system performance

OpenAIRE

Genci Sharko; Nike Shanku

2010-01-01

Power quality is a set of boundaries that allows electrical systems to function in their intended manner without significant loss of performance or life. The term is used to describe electric power that drives an electrical load and the load's ability to function properly with that electric power. Without the proper quality of the power, an electrical device may malfunction, fail prematurely or not operate at all. There are many reasons why the electric power can be of poor quality and many m...
Quality assurance in nuclear power plant

International Nuclear Information System (INIS)

Magalhaes, M.T. de

1981-01-01

The factors related to the licensing procedures of a nuclear power plant (quality assurance and safety analysis) are presented and discussed. The consequences of inadequate attitudes towards these factors are shown and suggestions to assure the safety of nuclear power plants in Brazil are presented. (E.G.) [pt
ASSESSMENT OF POWER QUALITY DISTURBANCE USING EXPERT SYSTEM

OpenAIRE

A.N.MALLESWARA RAO,; Dr. K.RAMESH REDDY,; Dr. B.V.SANKER RAM

2011-01-01

This paper describes a fuzzy expert system in order to understand and deal with power quality problems encountered in distribution systems in a better way. Because of the technology and software now available this monitoring is highly effective, the fuzzy expert system not only can provide information about the quality of the power and the causes of power system disturbances, but it can identify problem conditions throughout the system before they cause widespread customer complains and equip...
Physical-layer Network Coding in Two-Way Heterogeneous Cellular Networks with Power Imbalance

OpenAIRE

Thampi, Ajay K; Liew, Soung Chang; Armour, Simon M D; Fan, Zhong; You, Lizhao; Kaleshi, Dritan

2016-01-01

The growing demand for high-speed data, quality of service (QoS) assurance and energy efficiency has triggered the evolution of 4G LTE-A networks to 5G and beyond. Interference is still a major performance bottleneck. This paper studies the application of physical-layer network coding (PNC), a technique that exploits interference, in heterogeneous cellular networks. In particular, we propose a rate-maximising relay selection algorithm for a single cell with multiple relays assuming the decode...
Power limit and quality limit of natural circulation reactor

International Nuclear Information System (INIS)

Zhao Guochang; Ma Changwen

1997-01-01

The circulation characteristics of natural circulation reactor in boiling regime are researched. It is found that, the circulation mass flow rate and the power have a peak value at a mass quality respectively. Therefore, the natural circulation reactor has a power limit under certain technological condition. It can not be increased steadily by continually increasing the mass quality. Corresponding to this, the mass quality of natural circulation reactor has a reasonable limit. The relations between the maximum power and the reactor parameters, such as the resistance coefficient, the working pressure and so on, are analyzed. It is pointed out that the power limit of natural circulation reactor is about 1000 MW at present technological condition. Taking the above result and low quality stability experimental result into account, the authors recommend that the reasonable mass quality of natural circulation reactor working in boiling regime is from 2% to 3% under the researched working pressure
Quality assurance organization for nuclear power plants

International Nuclear Information System (INIS)

1983-01-01

This Safety Guide provides requirements, recommendations and illustrative examples for structuring, staffing and documenting the organizations that perform activities affecting quality of a nuclear power plant. It also provides guidance on control of organization interfaces, and establishment of lines for direction, communication and co-ordination. The provisions of this Guide are applicable to all organizations participating in any of the constituent areas of activities affecting quality of a nuclear power plant, such as design, manufacture, construction, commissioning and operation
Quality control of Ling'ao nuclear power station civil construction

International Nuclear Information System (INIS)

Lu Buliang; Ye Changyuan

2001-01-01

Based on the quality control model adopted during Ling'ao Nuclear Power Station construction, the author briefly introduces quality control process of some main civil construction activities (reinforced concrete, steel liner, steel works and prestressing force) of nuclear power station, and makes some descriptions on non-conformance control of civil works. These quality control processes described come from the concrete practice during civil construction of Ling'ao Nuclear Power Station, and are based on Daya Bay Nuclear Power Station construction experience
Quality assurance programme of Temelin nuclear power plant

International Nuclear Information System (INIS)

Eybl, J.; Nowak, O.

1988-01-01

The fundamental principle of the system of quality assurance in Czechoslovak nuclear power is quality assurance at all stages of the construction and operation of nuclear power plants and the grading fo measures taken, this in dependence on the impact on nuclear safety of the respective nuclear installation or its part. The system has been made fully operational during the construction of nuclear power plants in Temelin and Mochovce. State surveillance is executed by the Czechoslovak Atomic Energy Commission, and the Czech and Slovak Offices for Work Safety. Briefly discussed are the tasks of the building subcontractor of the Temelin nuclear power plant with regard to the programme of quality assurance as well as the results of the solution of the respective research tasks. The programme of quality assurance classifies the selected sections of the structure of a nuclear power plant into three safety categories. No part of the structure is classified into the first category, the second category includes, e.g., the reactor building, cooling tanks and diesel generator units, the third includes the reactor building and the building of auxiliary workshops. Attention is also paid to the problems of the qualification of personnel and to inspection activity. (Z.M.). 12 refs
Heterogeneous tiny energy: An appealing opportunity to power wireless sensor motes in a corrosive environment

International Nuclear Information System (INIS)

Qiao, Guofu; Sun, Guodong; Li, Hui; Ou, Jinping

2014-01-01

Highlights: • Ultra-low ambient energy was scavenged to power the first of its kind wireless corrosion sensors. • Three feasible tiny-energy sources were exploited for long-term corrosion monitoring. • Automatic recharging control of heterogeneous tiny energy was proposed for human-free monitoring. • Corrosion itself was applied as an energy source to power the wireless corrosion-monitoring motes. - Abstract: Reinforcing steel corrosion is a significant factor leading to the durability deterioration of reinforced concrete (RC) structures. The on-line monitoring of the corrosion of RC structures in a long-term, human-free manner is not only valuable in industry, but also a significant challenge in academia. This paper presents the first of its kind corrosion-monitoring approach that only exploits three heterogeneous tiny energy sources to power commercial-off-the-shelf wireless sensor motes such that the corrosion-related data are automatically and autonomously captured and sent to users via wireless channels. We first investigated the availability of these three tiny energy sources: corrosion energy, a cement battery, and a weak solar energy. In particular, the two former energy sources inherently exist in RC structures and can be generated continually in the service-life of RC structures, which beneficial for the prospects of long-term corrosion monitoring. We then proposed a proof-of-concept prototype, which consisted of a Telosb wireless sensor mote and an energy harvester in order to evaluate the feasibility and effectiveness of the ultralow-power ambient energy as a type of power supply in corrosion monitoring applications. The critical metrics for the holographic monitoring of RC structures, including electrochemical noise, humidity and temperature, were successfully acquired and analysed using a post-processing program. This paper describes a unique and novel approach towards the realisation of smart structural monitoring and control system in the
Hybrid power filter for advanced power quality in industrial systems

Czech Academy of Sciences Publication Activity Database

Švec, J.; Müller, Z.; Kasembe, A. G.; Tlustý, J.; Valouch, Viktor

2013-01-01

Roč. 103, october 2013 (2013), s. 157-167 ISSN 0378-7796 R&D Projects: GA AV ČR IAA200760703 Institutional research plan: CEZ:AV0Z20570509 Institutional support: RVO:61388998 Keywords : hybrid power filter * power quality * industrial system Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 1.595, year: 2013 http://www.sciencedirect.com/science/article/pii/S0378779613001417
Development of a VxWorks-based distributed power quality monitoring system

Energy Technology Data Exchange (ETDEWEB)

Shin, M.J.; Kim, S.J.; Son, Y.I.; Kang, S.H. [Myongji Univ., Yongin (Korea, Republic of). Next-generation Power Technology Center

2007-07-01

Electric utilities are becoming increasingly concerned about power quality because end user equipment is more sensitive to disturbances within the power supply system and also within the consumer facilities. In order to improve the quality of electricity, the sources and causes of disturbances must be known. However, voltage sag and swell, wave-faults and momentary interruptions are difficult to detect and avoid unless power quality monitoring devices are installed permanently. The impact that alternative energy sources have on power quality was also discussed. When distributed generation is connected to the power grid, it can generate and supply more reliable power to the grid. For a reliable interconnection of distributed power to the grid, monitoring systems should display the status of distributed power and record power events. Lack of source stability in distributed generation such as solar-cells or wind-power creates events that should be measured and stored immediately. This paper presented a newly developed real-time power quality monitoring system for distributed power systems. The system is based on a real-time operating system (OS) and can therefore handle many events that happen simultaneously. The proposed system contains a digital signal processor (MPC7410, Motorola) and an A/D board (VMIVME3122, GE). VxWorks was used to implement the monitoring algorithm. This paper outlined the structure and the functions of the developed Distributed Power Quality Monitoring System. Some experiments were conducted to test the performance of the proposed system. According to test results, the system is compatible with standards of the Institute of Electrical and Electronics Engineers (IEEE) for power quality monitoring. 15 refs., 1 tab., 18 figs.
Lead/acid batteries in systems to improve power quality

Science.gov (United States)

Taylor, P.; Butler, P.; Nerbun, W.

Increasing dependence on computer technology is driving needs for extremely high-quality power to prevent loss of information, material, and workers' time that represent billions of dollars annually. This cost has motivated commercial and Federal research and development of energy storage systems that detect and respond to power-quality failures in milliseconds. Electrochemical batteries are among the storage media under investigation for these systems. Battery energy storage systems that employ either flooded lead/acid or valve-regulated lead/acid battery technologies are becoming commercially available to capture a share of this emerging market. Cooperative research and development between the US Department of Energy and private industry have led to installations of lead/acid-based battery energy storage systems to improve power quality at utility and industrial sites and commercial development of fully integrated, modular battery energy storage system products for power quality. One such system by AC Battery Corporation, called the PQ2000, is installed at a test site at Pacific Gas and Electric Company (San Ramon, CA, USA) and at a customer site at Oglethorpe Power Corporation (Tucker, GA, USA). The PQ2000 employs off-the-shelf power electronics in an integrated methodology to control the factors that affect the performance and service life of production-model, low-maintenance, flooded lead/acid batteries. This system, and other members of this first generation of lead/acid-based energy storage systems, will need to compete vigorously for a share of an expanding, yet very aggressive, power quality market.
Composition heterogeneity analysis for DUPIC fuel(I) - Statistical analysis

Energy Technology Data Exchange (ETDEWEB)

Choi, Hang Bok [Korea Atomic Energy Research Institute, Taejon (Korea)

1999-08-01

The fuel composition heterogeneity effect on reactor performance parameters was assessed by refueling simulations for three DUPIC fuel options of fuel composition heterogeneity control: the fissile content adjustment, the reactivity control by slightly enriched and depleted uranium, and the reactivity control by natural uranium. For each DUPIC fuel option, the simulations were performed using 30 heterogeneous fuel types which were determined by the agglomerative hierarchical clustering method. The heterogeneity effect was considered during the refueling simulation by randomly selecting fuel types for the refueling operation. The refueling simulations of the heterogeneous core have shown that the key performance parameters such as the maximum channel power (MCP), maximum bundle power (MBP), and channel power peaking factor (CPPF) are close to those of the core that has single fuel type. For the three DUPIC fuel options, the uncertainties of MCP, MBP, and CPPF due to the fuel composition heterogeneity are less than 0.6, 1.5 and 0.8%, respectively, including the uncertainty of the group-average fuel property. This study has shown that the three DUPIC fuel options reduces the composition heterogeneity effectively and the zone power control system has a sufficient margin to adjust the perturbations cased by the fuel composition heterogeneity. 15 refs., 28 figs.,10 tabs. (Author)
Standards for measurements and testing of wind turbine power quality

Energy Technology Data Exchange (ETDEWEB)

Soerensen, P [Risoe National Lab., Roskilde (Denmark); Gerdes, G; Klosse, R; Santjer, F [DEWI, Wilhelmshaven (Germany); Robertson, N; Davy, W [NEL, Glasgow (United Kingdom); Koulouvari, M; Morfiadakis, E [CRES, Pikermi (Greece); Larsson, Aa [Chalmers Univ. of Technology, Goeteborg (Sweden)

1999-03-01

The present paper describes the work done in power quality sub-task of the project `European Wind Turbine Testing Procedure Developments` funded by the EU SMT program. The objective of the power quality sub-task has been to make analyses and new recommendation(s) for the standardisation of measurement and verification of wind turbine power quality. The work has been organised in three major activities. The first activity has been to propose measurement procedures and to verify existing and new measurement procedures. This activity has also involved a comparison of the measurements and data processing of the participating partners. The second activity has been to investigate the influence of terrain, grid properties and wind farm summation on the power quality of wind turbines with constant rotor speed. The third activity has been to investigate the influence of terrain, grid properties and wind farm summation on the power quality of wind turbines with variable rotor speed. (au)
Quality management of nuclear power plants

International Nuclear Information System (INIS)

Maxwell, D.A.; Hille, F.J.M.

1995-01-01

The paper discusses the various approaches to quality management and the progressive development from traditional quality assurance (QA) concepts through integrated and performance based quality management systems to total quality management. Experience has shown that in many cases the traditional implementation of QA in nuclear power plant life-cycle activities has resulted in limited benefits. The paper outlines the advantages of developing an integrated quality management system, which, besides satisfying the QA standards, focuses on the performance of an organization. This reflects the approach implicit in the proposed revisions of the IAEA QA standards (code and guides). Such a quality management system provides the framework within which processes are controlled to meet the business objectives and is capable of accommodating easily new requirements, such as environmental management. An integrated quality management system should not be focused specifically on regulatory (and hence nuclear safety) issues, but should constitute the whole management system of the organization, of which safety and the environment are of course important elements. The paper gives a practical example of this approach implemented company wide. This approach is similar to other approaches in place or being developed by many Foratom members. The paper also lists the components of total quality management, which is considered to constitute the future direction for the nuclear power industry. The quality management system is the primary vehicle to meet the fundamental objectives, but total quality can only be realized by developing the full potential of people through team work in order to continuously improve the system and the performance of the organization by focusing on internal as well as external customers. (author). 6 refs, 3 figs, 2 tab
Power Quality. Implications at the Point of Connection

Energy Technology Data Exchange (ETDEWEB)

Cobben, J.F.G.

2007-06-12

The main developments in the field of power quality and mentioned before were an important trigger in arriving at the research objectives. Condensing all information three main research objectives can be described as: (a) Classification of power quality phenomena to arrive at an analysis tool for grid operators, which makes it possible to handle an enormous amount of data and to give customers and the regulator clearer information about the quality of supply voltage; (b) The influence of dispersed generation due to a large amount of renewable energy sources on power quality, especially on the voltage level and slow voltage variations. Also the possible contribution to the harmonic distortion is analysed; (c) Power quality interaction between 'supply' voltage and 'exchanged' current at the point of common coupling (point of connection or POC to the grid). Especially the relation between current capacity of a POC, the grid impedance and the current at the POC is analysed for harmonics and flicker. In chapter 1 power quality in general is described, the problems are stated and the research topics discussed. Further understanding of the different power quality phenomena, is the topic of chapter 2 and the need to use the indices is described. Also the need to develop methods for compressing power quality data and to make this data fit for use is described. The classification explained in this chapter is an example of practical solution, which has been implemented in a system for substation automation. In chapter 3, the voltage magnitude variation as power quality phenomena is analysed. The influence of dispersed generation in relation to this phenomenon is studied. Also the limits of implementing dispersed generation in existing low voltage grids are calculated. The limited possibilities of voltage level regulation with reactive power in the low voltage grid are described, including the influences on the losses in the grid. Chapter 4 is the chapter

Optimal Design of TCR/FC in Electric Arc Furnaces for Power Quality Improvement in Power Systems

Directory of Open Access Journals (Sweden)

Mahdi TORABIAN ESFAHANI

2009-12-01

Full Text Available Electric Arc Furnaces (EAFs are unbalanced, nonlinear and time varying loads, which can cause many problems in the power system quality. As the use of arc furnace loads increases in industry, the importance of the power quality problems also increase. So in order to optimize the usages of electric power in EAFs, it is necessary to minimize the effects of arc furnace loads on power quality in power systems as much as possible. Therefore, in this paper, design and simulation of an electric plant supplying an arc furnace is considered. For this purpose, a three phase arc furnace model, which can simulate all the mentioned power quality indices, is developed based on Hyperbolic -Exponential model (V-I model. Then by considering the high changes of reactive power and voltage flicker of nonlinear furnace load, a thyristor controlled reactor compensation with fixed capacitor (TCR/FC are designed and simulated. In this procedure, the reactive power is measured so that maximum speed and accuracy are achieved. Finally, simulation results verify the accuracy of the load modelling and show the effectiveness of the proposed TCR/FC model for reactive compensating of the EAF.
National survey provides average power quality profiles for different customer groups

International Nuclear Information System (INIS)

Hughes, B.; Chan, J.

1996-01-01

A three year survey, beginning in 1991, was conducted by the Canadian Electrical Association to study the levels of power quality that exist in Canada, and to determine ways to increase utility expertise in making power quality measurements. Twenty-two utilities across Canada were involved, with a total of 550 sites being monitored, including residential and commercial customers. Power disturbances, power outages and power quality were recorded for each site. To create a group average power quality plot, the transient disturbance activity for each site was normalized to a per channel, per month basis and then divided into a grid. Results showed that the average power quality provided by Canadian utilities was very good. Almost all the electrical disturbance within a customer premises were created and stayed within those premises. Disturbances were generally beyond utility control. Utilities could, however, reduce the amount of time the steady-state voltage exceeds the CSA normal voltage upper limit. 5 figs
Dynamic heterogeneity in life histories

DEFF Research Database (Denmark)

Tuljapurkar, Shripad; Steiner, Uli; Orzack, Steven Hecht

2009-01-01

or no fixed heterogeneity influences this trait. We propose that dynamic heterogeneity provides a 'neutral' model for assessing the possible role of unobserved 'quality' differences between individuals. We discuss fitness for dynamic life histories, and the implications of dynamic heterogeneity...... generate dynamic heterogeneity: life-history differences produced by stochastic stratum dynamics. We characterize dynamic heterogeneity in a range of species across taxa by properties of the Markov chain: the entropy, which describes the extent of heterogeneity, and the subdominant eigenvalue, which...... distributions of lifetime reproductive success. Dynamic heterogeneity contrasts with fixed heterogeneity: unobserved differences that generate variation between life histories. We show by an example that observed distributions of lifetime reproductive success are often consistent with the claim that little...
Wind energy systems solutions for power quality and stabilization

CERN Document Server

Ali, Mohd Hasan

2012-01-01

Unlike conventional power plants, wind plants emit no air pollutants or greenhouse gases--and wind energy is a free, renewable resource. However, the induction machines commonly used as wind generators have stability problems similar to the transient stability of synchronous machines. To minimize power, frequency, and voltage fluctuations caused by network faults or random wind speed variations, control mechanisms are necessary. Wind Energy Systems: Solutions for Power Quality and Stabilization clearly explains how to solve stability and power quality issues of wind generator systems. Covering
Seamless interworking architecture for WBAN in heterogeneous wireless networks with QoS guarantees.

Science.gov (United States)

Khan, Pervez; Ullah, Niamat; Ullah, Sana; Kwak, Kyung Sup

2011-10-01

The IEEE 802.15.6 standard is a communication standard optimized for low-power and short-range in-body/on-body nodes to serve a variety of medical, consumer electronics and entertainment applications. Providing high mobility with guaranteed Quality of Service (QoS) to a WBAN user in heterogeneous wireless networks is a challenging task. A WBAN uses a Personal Digital Assistant (PDA) to gather data from body sensors and forwards it to a remote server through wide range wireless networks. In this paper, we present a coexistence study of WBAN with Wireless Local Area Networks (WLAN) and Wireless Wide Area Networks (WWANs). The main issue is interworking of WBAN in heterogenous wireless networks including seamless handover, QoS, emergency services, cooperation and security. We propose a Seamless Interworking Architecture (SIA) for WBAN in heterogenous wireless networks based on a cost function. The cost function is based on power consumption and data throughput costs. Our simulation results show that the proposed scheme outperforms typical approaches in terms of throughput, delay and packet loss rate.
Power quality and integration of wind farms in weak grids in India

Energy Technology Data Exchange (ETDEWEB)

Soerensen, P.; Hauge Madsen, P. [Risoe National Lab., Roskilde (Denmark). Wind Energy and Atmospheric Physics Dept.; Vikkelsoe, A.; Koelbaek Jensen, K. [Danske Elvaerkers Forening Udredningsafdelingen (DEFU), Lyngby (Denmark); Fathima, K.A.; Unnikrishnan, A.K.

2000-04-01

This is the final report of a joint Danish and Indian project' Power Quality and Integration of Wind Farms in Weak Grids'. The power quality issues have been studied and analysed with the Indian conditions as a case. On the basis of meetings with Danish wind turbine industry, Indian electricity boards, nodal agencies, wind turbine industry and authorities, the critical power quality as-pects in India have been identified. Measurements on selected wind farms and wind turbines have quantified the power quality, and analyses of power quality issues, especially reactive power compensation, have been performed. Based on measurements and analyses, preliminary recommendations for grid integration of wind turbines in weak grids have been formulated. (au)
Power transformation for enhancing responsiveness of quality of life questionnaire.

Science.gov (United States)

Zhou, YanYan Ange

2015-01-01

We investigate the effect of power transformation of raw scores on the responsiveness of quality of life survey. The procedure maximizes the paired t-test value on the power transformed data to obtain an optimal power range. The parallel between the Box-Cox transformation is also investigated for the quality of life data.
ASSESSMENT OF THE ELECTRIC POWER QUALITY ON THE POLISH FISHING BOATS

Directory of Open Access Journals (Sweden)

Dariusz TARNAPOWICZ

2015-07-01

Full Text Available Power quality is an important problem for electrical systems. Electricity receivers should operate at nominal conditions. Each deviation from nominal values may cause the malfunction of electrical devices, decreasing their durability and per-manently damage the appliance. The importance of electric power quality for technical systems and individual electrical devices on fishing boats is fundamental. Utilization of equipment powered by electrical energy with a reduced quality resulting in economical losses and the treat to the screw's safety. Researches of the electrical energy's quality were carried out almost any type of fishing boats. This article presents the results of researches concerning the quality of electrical energy performed on a representative type of fishing boats. It shortly evaluates the results of tests and suggests solutions to improve the power quality parameters.
Research on Holographic Evaluation of Service Quality in Power Data Network

Science.gov (United States)

Wei, Chen; Jing, Tao; Ji, Yutong

2018-01-01

With the rapid development of power data network, the continuous development of the Power data application service system, more and more service systems are being put into operation. Following this, the higher requirements for network quality and service quality are raised, in the actual process for the network operation and maintenance. This paper describes the electricity network and data network services status. A holographic assessment model was presented to achieve a comprehensive intelligence assessment on the power data network and quality of service in the operation and maintenance on the power data network. This evaluation method avoids the problems caused by traditional means which performs a single assessment of network performance quality. This intelligent Evaluation method can improve the efficiency of network operation and maintenance guarantee the quality of real-time service in the power data network..
Application of the Fuzzy Computational Intelligence in Power Quality Data Management

Directory of Open Access Journals (Sweden)

Hoda Farag

2017-03-01

Full Text Available In Electrical Power Distribution System the sustained availability and quality of electric power are the main challenge they need to satisfy so overcoming the power quality (PQ degradation became an asset. This Paper addresses the perfect load management using the computational techniques by analyzing the data of the system taking into account the density of the feeding nodes and its distribution also the classification of major Power quality degradations such as power factor and harmonics in the System and The methodology will be illustrated, simulated and evaluated using the fuzzy technique clustering the data and on an Artificial Neural Network (ANN to achieve the optimum utilization of the energy loads and perfect load management and optimization. Simulation results demonstrate the effectiveness of the proposed algorithm in reducing the power and energy losses, improving the quality of the electric power system.
Decarbonising the power sector via technological change – differing contributions from heterogeneous firms

International Nuclear Information System (INIS)

Schmidt, Tobias S.; Schneider, Malte; Hoffmann, Volker H.

2012-01-01

In the power sector, technological change is a key lever to address the decarbonisation needed to avoid dangerous climate change. Policy makers aim to accelerate and redirect technological change by targeting relevant firms via climate policy, e.g., the European Union Emissions Trading System (EU ETS), and climate-relevant technology policies, e.g., feed-in tariffs. Changes in firm's behaviour, i.e., their research and development (R and D) as well as diffusion activities, are at the heart of technological change. However, firms are heterogeneous actors with varying attributes which perceive policy differently. Hence, they can be expected to react very heterogeneously to these new policies. Based on an original dataset of 201 firms, we perform a cluster analysis grouping firms along their R and D and diffusion activity changes. We then compare these clusters with regards to the characteristics of the contained firms. Our analysis results in seven clusters showing very diverse contributions to low-carbon technological change, suggesting potential for policy to become more effective. A comparison of the firms' characteristics allows us to derive indicative recommendations on how to adjust the policy mix in order to induce contributions from most firms in the power sector. - Highlights: ► Firms differ strongly regarding their contribution low-carbon technological change. ► E.g., about 40% of the surveyed firms have not changed their R and D and diffusion activities. ► These observations cast doubt upon the effectiveness of current policy. ► From the findings recommendations for making policy more effective are derived.
Recognition of power quality events by using multiwavelet-based neural networks

Energy Technology Data Exchange (ETDEWEB)

Kaewarsa, Suriya; Attakitmongcol, Kitti; Kulworawanichpong, Thanatchai [School of Electrical Engineering, Suranaree University of Technology, 111 University Avenue, Muang District, Nakhon Ratchasima 30000 (Thailand)

2008-05-15

Recognition of power quality events by analyzing the voltage and current waveform disturbances is a very important task for the power system monitoring. This paper presents a novel approach for the recognition of power quality disturbances using multiwavelet transform and neural networks. The proposed method employs the multiwavelet transform using multiresolution signal decomposition techniques working together with multiple neural networks using a learning vector quantization network as a powerful classifier. Various transient events are tested, such as voltage sag, swell, interruption, notching, impulsive transient, and harmonic distortion show that the classifier can detect and classify different power quality signal types efficiency. (author)
Identification and simulation of the power quality problems using computer models

International Nuclear Information System (INIS)

Abro, M.R.; Memon, A.P.; Memon, Z.A.

2005-01-01

The Power Quality has become the main factor in our life. If this quality of power is being polluted over the Electrical Power Network, serious problems could arise within the modem social structure and its conveniences. The Nonlinear Characteristics of various office and Industrial equipment connected to the power grid could cause electrical disturbances to poor power quality. In many cases the electric power consumed is first converted to different form and such conversion process introduces harmonic pollution in the grid. These electrical disturbances could destroy certain sensitive equipment connected to the grid or in some cases could cause them to malfunction. In the huge power network identifying the source of such disturbance without causing interruption to the supply is a big problem. This paper attempts to study the power quality problem caused by typical loads using computer models paving the way to identify the source of the problem. PSB (Power System Blockset) Toolbox of MATLAB is used for this paper, which is designed to provide modem tool that rapidly and easily builds models and simulates the power system. The blockset uses the Simulink environment, allowing a model to be built using simple click and drag procedures. (author)
European wind turbine testing procedure developments. Task 2: Power quality

DEFF Research Database (Denmark)

Sørensen, Poul Ejnar; Friis Pedersen, Troels; Gerdes, G.

2001-01-01

The present report describes the work done in the power quality subtask of the European Wind Turbine Testing Procedure Developments project funded by the EU SMT program. The objective of the power quality subtask has been to make recommendations andprovide background for new standards...... for measurement and testing of wind turbine power quality. The focus in the work has been to support the ongoing standardisation work in IEC with a new standard IEC61400-21 for measurement and assessment of powerquality characteristics of grid connected wind turbines. The work has also been based on the power...... quality measuremnet procedure in the Measnet cooperation of European test stations for wind turbines. The first working item of the project has been toverify the state of the art of the measurement procedures by analyses and comparisons of the measurements and data processing software of the participating...
Quality assurance program manual for nuclear power plants. Volume I. Policies

International Nuclear Information System (INIS)

1976-01-01

The Consumers Power Company Quality Assurance Program Manual for Nuclear Power Plants consists of policies and procedures which comply with current NRC regulatory requirements and industry codes and standards in effect during the design, procurement, construction, testing, operation, refueling, maintenance, repair and modification activities associated with nuclear power plants. Specific NRC and industry documents that contain the requirements, including the issue dates in effect, are identified in each nuclear power plant's Safety Analysis Report. The requirements established by these documents form the basis for the Consumer Power Quality Assurance Program, which is implemented to control those structures, systems, components and operational safety actions listed in each nuclear power plant's Quality List (Q-List). As additional and revised requirements are issued by the NRC and professional organizations involved in nuclear activities, they will be reviewed for their impact on this manual, and changes will be made where considered necessary. CP Co 1--Consumers Power Company QA Program Topical Report is Volume I of this manual and contains Quality Assurance Program Policies applicable during all phases of nuclear power plant design, construction and operation
Power quality and reliability issues in a deregulated energy market

International Nuclear Information System (INIS)

Huggins, M.J.

1999-01-01

The challenge of maintaining power quality and reliability in Ontario's new competitive electricity market was the focus of this paper. The intention of Ontario's deregulation is to lower costs and give customers more power and choice. However, some fear that costs pressures may lead to poorer quality. This paper reviewed the causes, costs, and responsibilities, and made some suggestions concerning how customers can protect their interests as the market opens. It was suggested that in order to assure power quality, especially during the transition period, customers need to take care to design their systems and equipment to tolerate some quality variations. Conversely, utilities need to strive for at least minimum industry standards under most conditions. Contracts should be carefully crafted, with responsibilities for reliability and quality clearly stated. 2 refs
Informatization of items quality control for NI in nuclear power plant

International Nuclear Information System (INIS)

Zhang Jiankui; Zang Baiqi

2010-01-01

Design ideas, implementation methods and some key techniques for item quality control of NI in nuclear power plant are illustrated in this article according to item quality management mode. The item quality control method can improve the quality of NI, ensure the safety and lower the construction and operation cost of nuclear power plant. (authors)
Code on the safety of nuclear power plants: Quality assurance

International Nuclear Information System (INIS)

1988-01-01

This revised Code provides the principles and objectives for the establishment and implementation of quality assurance programmes applied to both the overall and each of the constituent activities associated with a nuclear power plant project. The quality assurance principles enumerated in the present Code can be usefully applied to nuclear facilities other than nuclear power plants. The quality assurance programme encompasses: (1) the activities that are necessary to achieve the appropriate quality of the respective item or service; and (2) the activities that are necessary for verifying that the required quality is achieved and that objective evidence is produced to that effect. Quality assurance is an essential aspect of good management and the quality assurance programme is the main management tool for a disciplined approach to all activities affecting quality, including, where appropriate, verification that each task has been satisfactorily performed and that necessary corrective actions have been implemented. The principles and objectives provided by the Code are applicable by all those responsible for the nuclear power plant, by plant designers, suppliers, architect-engineers, plant constructors, plant operators and other organizations participating in activities affecting quality. The Code is a revision of the previous Code of Practice (1978) on the same subject of interest to regulatory bodies and experts in quality assurance for design, siting and operation of nuclear power plants. Contents: Definitions; 1. Introduction; 2. Quality assurance programmes; 3. Organization; 4. Document control; 5. Design control; 6. Procurement control; 7. Control of items; 8. Process control; 9. Inspection and test control; 10. Non-conformance control; 11. Corrective actions; 12, Records; 13. Audits
Power quality improvement by using STATCOM control scheme in wind energy generation interface to grid

Science.gov (United States)

Kirmani, Sheeraz; Kumar, Brijesh

2018-01-01

“Electric Power Quality (EPQ) is a term that refers to maintaining the near sinusoidal waveform of power distribution bus voltages and currents at rated magnitude and frequency”. Today customers are more aware of the seriousness that the power quality possesses, this prompt the utilities to assure good quality of power to their customer. The power quality is basically customer centric. Increased focus of utilities toward maintaining reliable power supply by employing power quality improvement tools has reduced the power outages and black out considerably. Good power quality is the characteristic of reliable power supply. Low power factor, harmonic pollution, load imbalance, fast voltage variations are some common parameters which are used to define the power quality. If the power quality issues are not checked i.e. the parameters that define power quality doesn't fall within the predefined standards than it will lead into high electricity bill, high running cost in industries, malfunctioning of equipments, challenges in connecting renewable. Capacitor banks, FACTS devices, harmonic filters, SVC’s (static voltage compensators), STATCOM (Static-Compensator) are the solutions to achieve the power quality. The performance of Wind turbine generators is affected by poor quality power, at the same time these wind power generating plant affects the power quality negatively. This paper presents the STATCOM-BESS (battery energy storage system) system and studies its impact on the power quality in a system which consists of wind turbine generator, non linear load, hysteresis controller for controlling the operation of STATCOM and grid. The model is simulated in the MATLAB/Simulink. This scheme mitigates the power quality issues, improves voltage profile and also reduces harmonic distortion of the waveforms. BESS level out the imbalances caused in real power due to intermittent nature of wind power available due to varying wind speeds.
Quality assurance and nuclear power plant safety

International Nuclear Information System (INIS)

Mullan, J.V.

1983-01-01

Quality assurance in the nuclear industry was born in the late 1960s. Atomic Energy Control Board staff began its regulatory practice on quality assurance during that period. In this presentation the author traces the circumstances that first led to the establishment of Canadian nuclear power plant quality assurance programmes, summarizes progress over the last decade and a half, and outlines the current regulatory approach and what has been learned so far

Quality assurance for the maintenance of nuclear power plants

International Nuclear Information System (INIS)

Modemann, G.

1985-01-01

In order to maintain the quality of a nuclear power plant, it is essential that the numerous participants involved in maintenance work consistently fulfil their specified tasks, and that the quality control circuit is closed and functions smoothly. First of all, the report briefly explains the significance of the operational organization of a nuclear power plant and the role of the supervisory authority with the consulted experts. The quality control circuit for maintenance illustrates the tasks and cooperation of the participants. An idea is given of the testing and monitoring criteria which are implemented to assure the quality of the different types of maintenance and the procurement of supplies. (orig.) [de
Power quality measurement service in the support of large customers

Energy Technology Data Exchange (ETDEWEB)

Levesque, F. [Hydro-Quebec, Montreal, PQ (Canada)

2006-07-01

Power quality and how it is measured among Hydro Quebec's major customers were the focus of this conference presentation. Background information on Hydro Quebec and its customers was provided with reference to information on clients, employees and how the organization is organized. The presentation also included a discussion of power quality and how it is delivered at Hydro Quebec. For example, characteristics and target values of the voltage supplied by Hydro Quebec for high, medium and low voltages were examined. Personnel responsible for the grid have created a system to document each event submitted by customers. Documenting the actual power quality at the point of common coupling allows benchmarking of real data against announced characteristics and target values. This approach quantifies disturbances and helps to find and focus on disturbances that really influence large customers, mainly industrials. Portable and permanent installations issues were discussed followed by a discussion of a new service offering power quality metering on a regular basis. This metering service includes a complete analysis and technical support with dedicated expertise since customers are rarely fully experienced in power quality. The metering service is presented from the perspective of preventive maintenance with continuous quantification of a large number of indicators to assess the quality of the delivered power. Essential tools that customers can benefit from with this new service include real time electronic mail notification, weekly reporting and ad hoc technical support. This combination of various levels of services allows Hydro-Quebec to address the needs of these large customers in a flexible way. figs.
Electric power quality analysis methods. Application to voltage dips and harmonic disturbances

International Nuclear Information System (INIS)

Vanya, Ignatova

2006-10-01

The power quality concerns all the actors in the energy domains, that they are network administrators, suppliers, producers, or consumers of electricity. The research work presented in this PhD thesis is situated in the field of the power quality monitoring. Its objective is to introduce new techniques for analysis of power quality problems. There are different methods designed for the analysis of the power quality disturbances. This method reaches very good performances in the voltage dips analysis, as it allows segmenting, classifying and characterising these power quality disturbances. The periodic systems method allows the theoretical study of the generation and the propagation of harmonic disturbances in the network. Finally, the statistical matrix method has the objective to represent statistically electrical signals without loss of important information. (author)
Practical aspects of quality assurance in nuclear power plants in Japan

International Nuclear Information System (INIS)

Inoue, Kunio

1980-01-01

Based on the occurrence of accidents caused by inappropriateness in quality assurance in nuclear power plants, the nuclear power plant quality assurance investigation committee was organized in January, 1980, to examine comprehensively what the quality assurance should be from designing through operating stages of the equipments and systems of nuclear power stations, in order to prevent the recurrence of such accidents, to secure the safety and to improve the reliability. The committee established three subcommittees: the first is in charge of the investigation of quality assurance system based on the analyses of accidents, failures or abnormal events, the second in charge of the investigation of quality assurance system in nuclear industries, and the third in charge of the investigation by comparing domestic legal control and the organization for implementing inspection with those of foreign countries. In nuclear power plants in Japan, approximately 20 accidents or failures have occurred every year in the last 3 or 4 years. Many of them seem to be caused by quality assurance problems such as the misuse of materials or the inadequacy in machining. In addition, to this paper the tables showing the general quality assurance activity in, and the present status of permission, approval and inspection for Japanese nuclear power plants are attached. (Wakatsuki, Y.)
Influence of weight and type of planting material on fruit quality and its heterogeneity in pineapple [Ananas comosus (L.) Merrill].

Science.gov (United States)

Fassinou Hotegni, V Nicodème; Lommen, Willemien J M; Agbossou, Euloge K; Struik, Paul C

2014-01-01

Cultural practices can affect the quality of pineapple fruits and its variation. The objectives of this study were to investigate (a) effects of weight class and type of planting material on fruit quality, heterogeneity in quality and proportion and yield of fruits meeting European export standards, and (b) the improvement in quality, proportion and yield of fruits meeting export standards when flowering was induced at optimum time. Experiments were conducted in Benin with cvs Sugarloaf (a Perola type) and Smooth Cayenne. In cv. Sugarloaf, experimental factors were weight class of planting material (light, mixed, heavy) and time of flowering induction (farmers', optimum) (Experiment 1). In cv. Smooth Cayenne an additional experimental factor was the type of planting material (hapas, ground suckers, a mixture of the two) (Experiment 2). Fruits from heavy planting material had higher infructescence and fruit weights, longer infructescences, shorter crowns, and smaller crown: infructescence length than fruits from light planting material. The type of planting material in Experiment 2 did not significantly affect fruit quality except crown length: fruits from hapas had shorter crowns than those from ground suckers. Crops from heavy planting material had a higher proportion and yield of fruits meeting export standards than those from other weight classes in Experiment 1 only; also the type of planting material in Experiment 2 did not affect these variates. Heterogeneity in fruit quality was usually not reduced by selecting only light or heavy planting material instead of mixing weights; incidentally the coefficient of variation was significantly reduced in fruits from heavy slips only. Heterogeneity was also not reduced by not mixing hapas and ground suckers. Flowering induction at optimum time increased the proportion and yield of fruits meeting export standards in fruits from light and mixed slip weights and in those from the mixture of heavy hapas plus ground suckers.
Statistical Analysis of Spatiotemporal Heterogeneity of the Distribution of Air Quality and Dominant Air Pollutants and the Effect Factors in Qingdao Urban Zones

Directory of Open Access Journals (Sweden)

Xiangwei Zhao

2018-04-01

Full Text Available Air pollution has impacted people’s lives in urban China, and the analysis of the distribution and driving factors behind air quality has become a current research focus. In this study, the temporal heterogeneity of air quality (AQ and the dominant air pollutants across the four seasons were analyzed based on the Kruskal-Wallis rank-sum test method. Then, the spatial heterogeneity of AQ and the dominant air pollutants across four sites were analyzed based on the Wilcoxon signed-rank test method. Finally, the copula model was introduced to analyze the effect of relative factors on dominant air pollutants. The results show that AQ and dominant air pollutants present significant spatiotemporal heterogeneity in the study area. AQ is worst in winter and best in summer. PM10, O3, and PM2.5 are the dominant air pollutants in spring, summer, and winter, respectively. The average concentration of dominant air pollutants presents significant and diverse daily peaks and troughs across the four sites. The main driving factors are pollutants such as SO2, NO2, and CO, so pollutant emission reduction is the key to improving air quality. Corresponding pollution control measures should account for this heterogeneity in terms of AQ and the dominant air pollutants among different urban zones.
Results from power quality measurements in Germany - An overview

Energy Technology Data Exchange (ETDEWEB)

Gerdes, G.J.; Santjer, F. [German Wind Energy Inst, Wilhelmshaven (Germany)

1996-12-31

Grid interferences caused by wind turbines (WT) are getting a severe problem in Germany with the fast increasing number of installed turbines. The wind energy capacity was doubled annually in the past three years. The actual situation and the plannings for the next years will lead to a situation, where high wind energy penetration will exercise a big influence on the power and voltage quality of local utility networks. Measurements performed in Germany according to a national guideline show a big variety in power quality performance of WT`s, which does affect the requirements for grid connection and thus the economical situation of wind energy projects to a large extent. The results from more than 25 power quality measurements will be discussed in this paper. 5 refs., 5 figs., 1 tab.
Quality management for nuclear power plant operation: A manual

International Nuclear Information System (INIS)

1990-01-01

The experience from well operated nuclear power plants shows that achievement of safe, reliable and economic performance is closely related to a strong commitment and involvement by the management personnel. A system of controls is necessary to ensure that satisfactory quality in operation is achieved and maintained over the long term. The key to achieving and assuring quality lies in the ability of management to define performance objectives and to ensure that significant safety and reliability problems are prevented or detected early and resolved. This Manual has been developed by the IAEA to assist plant managers in fulfilling their responsibility with regard to the control and direction of quality and of quality assurance activities in nuclear power plant operation. It emphasizes quality objectives for nuclear power plant operation and indicates the way in which a quality system based on quality assurance principles as established in the IAEA NUSS documents can be used by managers to accomplish these objectives. Since the Manual is mainly directed at management personnel, it is presented in the form of short highlighted practices complemented by typical examples of forms and procedures. Since not all the activities under the heading of quality in operation could be covered in a single document, the activities selected for this Manual comprise those where it was felt that practical advice is generally needed. A pragmatic document useful for direct application by plant managers was the envisaged objective
Power quality in electric distribution systems

International Nuclear Information System (INIS)

Mohamed, A.A.S.

2005-01-01

the power quality of the electric system is defined by the constant values of the voltage and frequency, the good value of the power factor close to unity, and balanced three phase voltages and currents. capacitors are widely installed in distribution systems for reactive power compensation to achieve power and energy loss reduction, voltage regulation and system capacity release. the extent of these benefits depends greatly on low the capacitors are placed on the system . the problem of how to place capacitors on the system such that these benefits are achieved and / or maximized against the cost associated with the capacitor placement is termed the general capacitor placement problem.the presented mathematical model has been developed to determine the size, number, and location of fixed capacitor banks that will maximize the saving derived from reduction in peak power and energy loss, and that will minimize the capital and installation costs of capacitors
Quality management in an international nuclear power plant project

International Nuclear Information System (INIS)

Brion, J.; Crustin, J.

1975-01-01

SNR (Schneller Natriumgekuehlter Reaktor) is the fast reactor power plant being erected at Kalkar, Federal German Republic. Quality management in this project is a contractual obligation. Quality management is subdivided into quality engineering, set of actions performed before manufacturing, and quality control, set of material controls performed during fabrication. The two successive phases of the quality management are presented. The difficulties and improvment possibilities are discussed [fr
Adjustable Speed Drives and Power Quality

DEFF Research Database (Denmark)

Davari, Pooya; Yang, Yongheng; Zare, Firuz

2016-01-01

This paper provides an overview and proposes cost-effective and efficient opportunities in improving power quality in Adjustable Speed Drive (ASD) systems. In particular, an Electronic Inductor (EI) technique has been used in single drives to overcome the existing challenges in conventional...... frontend rectifiers even at partial loading conditions. Moreover, the effectiveness of the EI technique along with a phase-shifted current control in terms of improved grid current quality in multi-drive configurations is addressed. Furthermore, a novel DC-link current modulation scheme for multi...
Amelioration of Electrical Power Quality based on Modulated Power Filter Compensator

Directory of Open Access Journals (Sweden)

Karrar Hameed Kadhim

2017-08-01

Full Text Available This paper deals with the performance of modeling and implementation of Modulated Power Filter Compensator ( MPFC based on synchronous generator to enhance Electrical Power Quality (EPQ performance , rectification power factor , voltage fixity and decreasing transmission line losses for 300 km transmission line . In this paper (MPFC sketch attendants for intelligent network stability and optimum exploitation. The proposal Flexible AC Transmission Systems ( FACTS can be expanded to distributed renewable energy interface and exploitation systems and also will be easy to modify for voltage fixity, Achieve the required stability, perfect usage and Compensation requirements. MATLAB SIMLINK version R2009b were used as a model of (MPFC.
The Level of Power Quality Measurement and Evaluation in A Stone Crusher Plant

Directory of Open Access Journals (Sweden)

Mustafa ŞEKKELİ

2009-03-01

Full Text Available Both electric utilities and end users of electric power are becoming increasingly concerned about the quality of electric power. Quality of electrical energy in the electrical system that is requested continuous power (uninterrupted power, constant frequency and with constant amplitude can be explained by sinusoidal voltage. Deformation of voltage in the form of sinusoidal waveform is explained as a harmonic. Harmonics are most important factors in decreasing quality of energy in the electrical system. In industrial plants, existence of harmocins and voltage drop, causes serious problems both in plant and network. This problem affects the cost. In this study, a power quality measurements are carried out in stone crusher plant. Harmonics and voltage drop has been measured and evaluated with the power analyzer. In the power quality measurements, harmonic level of the plant is not so bad. However, it is recommended that compensation system with harmonic elimination can be established in plant.
Commissioning quality assurance for nuclear power plants

Energy Technology Data Exchange (ETDEWEB)

NONE

1986-09-01

This standard contains the requirements for the quality assurance program applicable to the commissioning phase of a nuclear power plant. This standard embodies the relevant quality assurance requirements of CSA Standard CAN3-N286.0, and is the governing Standard for commissioning quality assurance activities in the event of any conflicting requirements. This Standard applies to the commissioning of safety-related equipment, systems, and structures as identified by the owner. It may be applied to other equipment, systems, and structures at the discretion of the owner. 1 fig.
Commissioning quality assurance for nuclear power plants

International Nuclear Information System (INIS)

1986-09-01

This standard contains the requirements for the quality assurance program applicable to the commissioning phase of a nuclear power plant. This standard embodies the relevant quality assurance requirements of CSA Standard CAN3-N286.0, and is the governing Standard for commissioning quality assurance activities in the event of any conflicting requirements. This Standard applies to the commissioning of safety-related equipment, systems, and structures as identified by the owner. It may be applied to other equipment, systems, and structures at the discretion of the owner. 1 fig
Effect of power quality on windings temperature of marine induction motors. Part I: Machine model

Energy Technology Data Exchange (ETDEWEB)

Gnacinski, P. [Gdynia Maritime Univ., Dept. of Ship Electrical Power Engineering, Morska Str. 83, 81-225 Gdynia (Poland)

2009-10-15

Marine induction machines are exposed to various power quality disturbances appearing simultaneously in ship power systems: frequency and voltage rms value deviation, voltage unbalance and voltage waveform distortions. As a result, marine induction motors can be seriously overheated due to lowered supply voltage quality. Improvement of the protection of marine induction machines requires an appropriate method of power quality assessment and modification of the power quality regulations of ship classification societies. This paper presents an analytical model of an induction cage machine supplied with voltage of lowered quality, used in part II of the work (effect of power quality on windings temperature of marine induction motors. Part II. Results of investigations and recommendations for related regulations) for power quality assessment in ship power systems, and for justification of the new power quality regulations proposal. The presented model is suitable for implementation in an on-line measurement system. (author)
Hydrogeophysics and geochemistry reveal heterogeneity and water quality improvements in aquifer recharge and recovery (ARR) (Invited)

Science.gov (United States)

Parsekian, A.; Regnery, J.; Wing, A.; Knight, R. J.; Drewes, J. E.

2013-12-01

Aquifer recharge and recover (ARR) is the process of infiltrating water into the ground for storage and withdrawal through wells at a later time. Two significant challenges faced during the design of ARR systems are 1) evaluating aquifer heterogeneity and 2) understanding the rock fluid interactions; these knowledge gaps may have profound impacts on the volume of recoverable water and the improvement in water quality in comparison with the source-water. Our objective in this research is to leverage the advantages of hydrogeophysical measurements and geochemical sampling to reveal the properties of an aquifer through which ARR water travels with the goal of informing current operations and future design decisions. Combined geophysical and geochemical investigations reveal subsurface heterogeneity, indicate possible flow paths though the aquifer and quantify specific reductions in contaminant concentrations. Ground penetrating radar (GPR), electromagnetic induction (EMI) and electrical resistivity tomography (ERT) were used to image the subsurface throughout two key infiltration/extraction areas of an ARR site in Colorado, USA. The most valuable results came from 2.5D ERT revealing the structural patterns and suggesting the distribution of textural composition of unconsolidated sediments. Geochemical measurements on transects intersecting the geophysical measurements resolved bulk parameters (i.e. total organic carbon, cations, anions) and trace organic contaminants (e.g. trace organic compounds) and were also used to estimate mixing and water travel times and assess the performance of the ARR site regarding water quality and quantity. Our results indicate that the subsurface is highly heterogeneous at our study site and that the coarse-grained sedimentary units, acting as the best conduit for transporting water, are likely discontinuous. The electrical resistivity measurements indicate certain areas of the infiltration basins may have good hydraulic connections to
QUALITY EVALUATION OF THE TPP POWER GENERATING UNITS WEAR RECONDITIONING

Directory of Open Access Journals (Sweden)

E. M. Farhadzadeh

2016-01-01

Full Text Available Reconditioning of the power generating unit worn equipment and devices is conducted during the scheduled repair period. Quality of wear reconditioning is evaluated by technical state and repair work implementation. Quality of the repair work execution characterizes logistical activities of the power station and the repair services and is rated by a five-grade scale. There are three technical conditions: adequate, subject to reservations, falling short of the technical standard documentation requirements. In practical work these constraints give place to essential ambiguity of the decision. Further to regulating techniques by way of informational support, the authors propose conducting the wear-reconditioning quality evaluation (repair quality accordingly the technical-and-economic indexes pattern of change. The paper recommends applying similarly the fivegrade system in evaluating the power generating unit technical state and distinguishes intolerable, dissatisfactory, fair, good and model estimates. The study demonstrates the assessment criteria dependence on the character of reliability and economical efficiency of performance variation after the repair with increase or decrease of the technical-and-economic indexes in reference to their mean, minimum and maximum values before the repair. The cases ascribed to intolerable quality of the wear reconditioning are those with one or more technical-and-economic indexes that not only failed to improve their values but deteriorated, and at that they became the worst amongst observable values. The model quality estimate of the wear reconditioning is allotted under condition that the power unit technical-and-economic index valuations after the repair not merely improved but also exceeded the best among those under observation. The developed method and algorithm for quality evaluation of the scheduled repair implementation contribute to practical realization of the independent monitoring. This monitoring
Power Quality Regulation from an Economical and a Technical Point of View

International Nuclear Information System (INIS)

Partanen, Jarmo; Viljainen, Satu; Lassila, Jukka; Honkapuro, Samuli; Tahvanainen, Kaisa; Jaerventausta, Pertti; Maekinen, Antti; Kivikko, Kimmo

2005-06-01

An essential guideline for the implementation of power quality regulation - or any regulation for that matter - is that it needs to find the right balance between the interests of the different stakeholders. This is particularly important when assessing the inconvenience caused to customers by the failures in the electricity supply. Customers' experiences should obviously not be underestimated but it is equally important that excessive requirements concerning the power quality developments are not laid on the distribution companies, either - especially if they are not provided with adequate means to carry out the necessary developments. After all, regulation should encourage innovations, both organisational and technological, that benefit the industry in the long run - this applies to power quality developments as well as any other developments within the industry. Failing to do this, the investors will soon loose their interest in the electricity distribution business, and this will be extremely harmful for the capital-intensive industry. Regulators are currently developing versatile power quality regulation schemes in different countries. At this point it might be worth considering what benefits could be achieved if the framework for the power quality regulation schemes that are applied in different countries was the same - after all the goals are principally the same anyway. One of the obvious benefits would be that the regulators would have more comparable data on the observed power quality levels in different countries. In addition, those companies that operate in various markets could more easily transfer their best practices concerning the power quality developments from one market to another
Area Green Efficiency (AGE) of Two Tier Heterogeneous Cellular Networks

KAUST Repository

Tabassum, Hina

2012-10-03

Small cell networks are becoming standard part of the future heterogeneous networks. In this paper, we consider a two tier heterogeneous network which promises energy savings by integrating the femto and macro cellular networks and thereby reducing CO2 emissions, operational and capital expenditures (OPEX and CAPEX) whilst enhancing the area spectral efficiency (ASE) of the network. In this context, we define a performance metric which characterize the aggregate energy savings per unit macrocell area and is referred to as area green efficiency (AGE) of the two tier heterogeneous network where the femto base stations are arranged around the edge of the reference macrocell such that the configuration is referred to as femto-on-edge (FOE). The mobile users in macro and femto cellular networks are transmitting with the adaptive power while maintaining the desired link quality such that the energy aware FOE configuration mandates to (i) save energy, and (ii) reduce the co-channel interference. We present a mathematical analysis to incorporate the uplink power control mechanism adopted by the mobile users and calibrate the uplink ASE and AGE of the energy aware FOE configuration. Next, we derive analytical expressions to compute the bounds on the uplink ASE of energy aware FOE configuration and demonstrate that the derived bounds are useful in evaluating the ASE under worst and best case interference scenarios. Simulation results are produced to demonstrate the ASE and AGE improvements in comparison to macro-only and macro-femto configuration with uniformly distributed femtocells.

Power quality improvements of wind farms

Energy Technology Data Exchange (ETDEWEB)

Soebrink, Kent H. [Eltra (Denmark); Stoeber, Ralf; Schettler, Frank; Bergmann, Klaus [Siemens (Germany); Jenkins, Nicholas; Ekanayake, Janaka; Saad-Saoud, Zouhir; Liboa, Maria Luiza; Strbac, Goran [UMIST (United Kingdom); Kaas Pedersen, Joergen; Helgesen Pedersen, Knud Ole [Technical Univ. of Denmark (Denmark)

1998-06-01

The main objective of the project was to investigate how the power quality of the electrical output of wind farms could be improved by the use of modern high power electronic technology. Although the research is of direct application to wind energy it will also be relevant to many other types of small-scale generation embedded in utility distribution networks. The operation of wind turbines with asynchronous generators requires reactive power which, if supplied form the network, leads to low voltages and increased losses. In order to improve the power factor of the generation, fixed capacitors are usually used to provide reactive power. However, if they are sized for the full requirement of the wind farm, they can cause self-excitation and potentially damaging and hazardous overvoltages if the wind turbines` connection with the network is interrupted and they become islanded. An advanced Static VAr Compensator (ASVC) uses a power electronic converter to generate or absorb reactive power. They can be used to provide reactive power with rapid control and with only modestly sized passive components (i.e. small capacitors and reactors). The objective of the project was to combine research and development of this novel form of electronic equipment with its application to increase the use of renewable energy, and wind power in particular, in the European Union. (EG) 19 refs.
Determination of the relative power density distribution in a heterogeneous reactor from the results of measurements of the reactivity effects and the neutron importance function

International Nuclear Information System (INIS)

Bobrov, A. A.; Glushkov, E. S.; Zimin, A. A.; Kapitonova, A. V.; Kompaniets, G. V.; Nosov, V. I.; Petrushenko, R. P.; Smirnov, O. N.

2012-01-01

A method for experimental determination of the relative power density distribution in a heterogeneous reactor based on measurements of fuel reactivity effects and importance of neutrons from a californium source is proposed. The method was perfected on two critical assembly configurations at the NARCISS facility of the Kurchatov Institute, which simulated a small-size heterogeneous nuclear reactor. The neutron importance measurements were performed on subcritical and critical assemblies. It is shown that, along with traditionally used activation methods, the developed method can be applied to experimental studies of special features of the power density distribution in critical assemblies and reactors.
A Design of Wireless Sensor Networks for a Power Quality Monitoring System

Directory of Open Access Journals (Sweden)

Sanggil Kang

2010-11-01

Full Text Available Power grids deal with the business of generation, transmission, and distribution of electric power. Recently, interest in power quality in electrical distribution systems has increased rapidly. In Korea, the communication network to deliver voltage, current, and temperature measurements gathered from pole transformers to remote monitoring centers employs cellular mobile technology. Due to high cost of the cellular mobile technology, power quality monitoring measurements are limited and data gathering intervals are large. This causes difficulties in providing the power quality monitoring service. To alleviate the problems, in this paper we present a communication infrastructure to provide low cost, reliable data delivery. The communication infrastructure consists of wired connections between substations and monitoring centers, and wireless connections between pole transformers and substations. For the wireless connection, we employ a wireless sensor network and design its corresponding data forwarding protocol to improve the quality of data delivery. For the design, we adopt a tree-based data forwarding protocol in order to customize the distribution pattern of the power quality information. We verify the performance of the proposed data forwarding protocol quantitatively using the NS-2 network simulator.
A design of wireless sensor networks for a power quality monitoring system.

Science.gov (United States)

Lim, Yujin; Kim, Hak-Man; Kang, Sanggil

2010-01-01

Power grids deal with the business of generation, transmission, and distribution of electric power. Recently, interest in power quality in electrical distribution systems has increased rapidly. In Korea, the communication network to deliver voltage, current, and temperature measurements gathered from pole transformers to remote monitoring centers employs cellular mobile technology. Due to high cost of the cellular mobile technology, power quality monitoring measurements are limited and data gathering intervals are large. This causes difficulties in providing the power quality monitoring service. To alleviate the problems, in this paper we present a communication infrastructure to provide low cost, reliable data delivery. The communication infrastructure consists of wired connections between substations and monitoring centers, and wireless connections between pole transformers and substations. For the wireless connection, we employ a wireless sensor network and design its corresponding data forwarding protocol to improve the quality of data delivery. For the design, we adopt a tree-based data forwarding protocol in order to customize the distribution pattern of the power quality information. We verify the performance of the proposed data forwarding protocol quantitatively using the NS-2 network simulator.
Journal of EEA, Vol. 31, 2014 10 POWER QUALITY ASSESSMENT ...

African Journals Online (AJOL)

ABSTRACT. In this paper, electric power quality (PQ) in Walya- ... Commercial AC electric power systems are to operate at a sinusoidal ... Electric Power System in the two Factories. EPSC is ..... factor and reliability for industries. The design ...
Quality assurance in siting of Nuclear Power Plants

International Nuclear Information System (INIS)

2005-03-01

This guide describes the requirements of quality assurance programme (QAP) that need to be implemented at the siting stage, by the organisation having overall responsibility for the nuclear power plant. The scope of the guide covers the quality assurance aspects related to management, performance and assessment activities during siting stage of NPPs
Review of power quality applications of energy storage systems

Energy Technology Data Exchange (ETDEWEB)

Swaminathan, S.; Sen, R.K. [Sentech, Inc., Bethesda, MD (United States)

1997-05-01

Under the sponsorship of the US Department of Energy (DOE) Office of Utility Technologies, the Energy Storage Systems Analysis and Development Department at Sandia National Laboratories contracted Sentech, Inc., to assess the impact of power quality problems on the electricity supply system. This report contains the results of several studies that have identified the cost of power quality events for electricity users and providers. The large annual cost of poor power quality represents a national inefficiency and is reflected in the cost of goods sold, reducing US competitiveness. The Energy Storage Systems (ESS) Program takes the position that mitigation merits the attention of not only the DOE but affected industries as well as businesses capable of assisting in developing solutions to these problems. This study represents the preliminary stages of an overall strategy by the ESS Program to understand the magnitude of these problems so as to begin the process of engaging industry partners in developing solutions.
A study of electrical power network of renewable energies and water desalination research center using power quality phenomena and indices

International Nuclear Information System (INIS)

Segayer, Ali Mehemmed

2008-08-01

Renewable energies and water distillation research center (REWDRC) is a very strategic research facility and contains many important and critical industrial and electrical loads that must to be operated as a group to fulfill the requirements and the needs of the center in the operation of the main research facility of the center which a 10 MW reactor. Faults on the electrical or the industrial system can occur on many ways such as a malfunction in the questioned system, power quality related problem, or a failure of any of the loads (such as central ventilation or water circulation system or one of the substations) have a great diverse effect on the operation of the main research facility (reactor). In this research common problems due to power quality phenomena were studied, assessed through a assigning some power quality indices to the electrical network of the center so that the operational condition of the REWDRC electrical and industrial network could be evaluated. power quality indices (PQI) were assigned based on results of real time measurements at the points of common coupling of the network (PCC) and the initial power quality survey report. indices analysis was done using three methods which were the normalization method, method of comparing to the limit value and analysis of measurement data time function profile. As a result of this research a recommendation for safe operation against power quality disturbances was pointed out through a continuous monitoring of assigned power quality indices. (Author)
Self-Consistent Scheme for Spike-Train Power Spectra in Heterogeneous Sparse Networks.

Science.gov (United States)

Pena, Rodrigo F O; Vellmer, Sebastian; Bernardi, Davide; Roque, Antonio C; Lindner, Benjamin

2018-01-01

Recurrent networks of spiking neurons can be in an asynchronous state characterized by low or absent cross-correlations and spike statistics which resemble those of cortical neurons. Although spatial correlations are negligible in this state, neurons can show pronounced temporal correlations in their spike trains that can be quantified by the autocorrelation function or the spike-train power spectrum. Depending on cellular and network parameters, correlations display diverse patterns (ranging from simple refractory-period effects and stochastic oscillations to slow fluctuations) and it is generally not well-understood how these dependencies come about. Previous work has explored how the single-cell correlations in a homogeneous network (excitatory and inhibitory integrate-and-fire neurons with nearly balanced mean recurrent input) can be determined numerically from an iterative single-neuron simulation. Such a scheme is based on the fact that every neuron is driven by the network noise (i.e., the input currents from all its presynaptic partners) but also contributes to the network noise, leading to a self-consistency condition for the input and output spectra. Here we first extend this scheme to homogeneous networks with strong recurrent inhibition and a synaptic filter, in which instabilities of the previous scheme are avoided by an averaging procedure. We then extend the scheme to heterogeneous networks in which (i) different neural subpopulations (e.g., excitatory and inhibitory neurons) have different cellular or connectivity parameters; (ii) the number and strength of the input connections are random (Erdős-Rényi topology) and thus different among neurons. In all heterogeneous cases, neurons are lumped in different classes each of which is represented by a single neuron in the iterative scheme; in addition, we make a Gaussian approximation of the input current to the neuron. These approximations seem to be justified over a broad range of parameters as
Self-Consistent Scheme for Spike-Train Power Spectra in Heterogeneous Sparse Networks

Directory of Open Access Journals (Sweden)

Rodrigo F. O. Pena

2018-03-01

Full Text Available Recurrent networks of spiking neurons can be in an asynchronous state characterized by low or absent cross-correlations and spike statistics which resemble those of cortical neurons. Although spatial correlations are negligible in this state, neurons can show pronounced temporal correlations in their spike trains that can be quantified by the autocorrelation function or the spike-train power spectrum. Depending on cellular and network parameters, correlations display diverse patterns (ranging from simple refractory-period effects and stochastic oscillations to slow fluctuations and it is generally not well-understood how these dependencies come about. Previous work has explored how the single-cell correlations in a homogeneous network (excitatory and inhibitory integrate-and-fire neurons with nearly balanced mean recurrent input can be determined numerically from an iterative single-neuron simulation. Such a scheme is based on the fact that every neuron is driven by the network noise (i.e., the input currents from all its presynaptic partners but also contributes to the network noise, leading to a self-consistency condition for the input and output spectra. Here we first extend this scheme to homogeneous networks with strong recurrent inhibition and a synaptic filter, in which instabilities of the previous scheme are avoided by an averaging procedure. We then extend the scheme to heterogeneous networks in which (i different neural subpopulations (e.g., excitatory and inhibitory neurons have different cellular or connectivity parameters; (ii the number and strength of the input connections are random (Erdős-Rényi topology and thus different among neurons. In all heterogeneous cases, neurons are lumped in different classes each of which is represented by a single neuron in the iterative scheme; in addition, we make a Gaussian approximation of the input current to the neuron. These approximations seem to be justified over a broad range of
Guest Editorial Special Issue on Power Quality in Smart Grids

DEFF Research Database (Denmark)

Guerrero, Josep M.

2017-01-01

-healing from power disturbances, efficient energy management, automation based on ICT and advanced metering infrastructures (smart metering), integration of distributed power generation, renewable energy resources and storage units as well as high power quality and reliability. In this regard, the concept...
Quality control of three main materials for civil construction of nuclear power plant

International Nuclear Information System (INIS)

Wang Feng

2011-01-01

The construction and operation of nuclear power plant is a systematic engineering. To ensure quality and safety of nuclear power plants, each work from design to operation can have certain impact on the quality and safety of the project. The quality of each related work shall be controlled. Starting from the quality control over raw materials for the civil construction of nuclear power plant, this article mainly analyzes how to control the quality and manage the three main materials of steel, concrete and modular parts in the civil construction. (author)
Quality control during construction of power plants

International Nuclear Information System (INIS)

Hartstern, R.F.

1982-01-01

This paper traces the background and examines the necessity for a program to control quality during the construction phase of a power plant. It also attempts to point out considerations for making these programs cost effective
Nuclear power project construction quality acceptance standards Implementation and discussion

International Nuclear Information System (INIS)

Lai Shifu

2013-01-01

Project quality construction acceptance is an important element of nuclear power project quality management. Based on characteristics of NPP construction and refer to national construction quality acceptance code and industry regulation, this paper introduces and discusses NPP construction quality acceptance regulation improvement and implementation under current situation. (authors)
power quality study of the electrical system of the second research reactor of egypt

International Nuclear Information System (INIS)

Fathi, H.M.E.

2007-01-01

identifying problems in an electrical network which may results in an extensive damage occur is advisable for any power system. monitoring of power quality is necessary for maintaining accurate operation of sensitive equipment, it also ensures that unnecessary for maintaining accurate operation of sensitive equipment, it also ensures that unnecessary energy losses in a power system are kept at a minimum which lead to more profits. with advanced in technology growing of industrial/commercial facilities in many region. power quality problems have been a major concern among engineers; particularly in an industrial environment, where there are many large-scale type of equipment.thus, it would be useful to monitor and analyze the power quality problems.determination of power quality requires the identification of any anomalous behavior on a power system, which adversely affects the normal operation of electrical or electronic equipment. the choice of monitoring equipment in a survey is also important to ascertain a solution to these power quality problems. a power quality survey involves gathering data resources; analyzing the data (with reference to power quality standard); then , if problems exist, recommendation of mitigation techniques. the main objective of the present work is to identify power quality problems in second research reactor of egypt (ETRR-2). electrical power is supplied to the installation via tow incoming feeders from tow different substations (incoming feeder from new Abo-Zabal substation and incoming feeder from old Abo-Zabal substation ) to keep good reliability , each feeder is designed to carry the full load of ETRR-2. the monitoring investigations were performed at the second research reactor of egypt for both feeders at different operation conditions
Improvement of power quality using distributed generation

Energy Technology Data Exchange (ETDEWEB)

Moreno-Munoz, A.; Lopez-Rodriguez, M.A.; Flores-Arias, J.M.; Bellido-Outerino, F.J. [Universidad de Cordoba, Departamento A.C., Electronica y T.E., Escuela Politecnica Superior, Campus de Rabanales, E-14071 Cordoba (Spain); de-la-Rosa, J.J.G. [Universidad de Cadiz, Area de Electronica, Dpto. ISA, TE y Electronica, Escuela Politecnica Superior Avda, Ramon Puyol, S/N, E-11202-Algeciras-Cadiz (Spain); Ruiz-de-Adana, M. [Universidad de Cordoba, Departamento de Quimica Fisica y Termodinamica Aplicada, Campus de Rabanales, E-14071 Cordoba (Spain)

2010-12-15

This paper addresses how Distributed Generation (DG), particularly when configured in Combined Heat and Power (CHP) mode, can become a powerful reliability solution in highlight automated factories, especially when integrated with complimentary Power Quality (PQ) measures. The paper presents results from the PQ audit conducted at a highly automated plant over last year. It was found that the main problems for the equipment installed were voltage sags. Among all categories of electrical disturbances, the voltage sag (dip) and momentary interruption are the nemeses of the automated industrial process. The paper analyzes the capabilities of modern electronic power supplies and the convenience of embedded solution. Finally it is addressed the role of the DG/CHP on the reliability of digital factories. (author)
Basic Study of Establishment of Quality Assurance Processes to Develop an Integrated Quality Assurance System for Nuclear Power Plant Construction

International Nuclear Information System (INIS)

Lim, Byungki; Moon, Byeongsuk; Lee, Jae Kyoung

2014-01-01

An integrated quality assurance system has necessitated carrying out quality assurance programs in a systematic manner because the opportunities to expand business in overseas markets have increased since the export of a nuclear power plant to UAE in 2009. In this study, we use PDCA method to systematically analyze the quality assurance procedures that were used in previous projects for constructing nuclear power plants. We reached a classification system of quality assurance processes at each phase of nuclear power plant construction by integrating similar work related to quality such as planning, design, equipment manufacturing, construction and start-up. We also established a hierarchy of quality assurance processes to develop an integrated quality assurance system as a technology goal to be developed later. To obtain most updated quality assurance activities, a quality assurance process is structured by integrating similar works analyzed from quality assurance procedures through PDCA cycle method. At the implementation phase of Hierarchy of quality processes and sequence of processes for constructing nuclear power plant are established in this study. Integrated quality assurance system is to be developed by connecting organizations as well as stakeholders such as owners, Architect engineering, suppliers, contractors, and sub-contractors to carry out assigned work efficiently
Basic Study of Establishment of Quality Assurance Processes to Develop an Integrated Quality Assurance System for Nuclear Power Plant Construction

Energy Technology Data Exchange (ETDEWEB)

Lim, Byungki; Moon, Byeongsuk; Lee, Jae Kyoung [Korea Hydro and Nuclear Power Co. Ltd., Daejeon (Korea, Republic of)

2014-05-15

An integrated quality assurance system has necessitated carrying out quality assurance programs in a systematic manner because the opportunities to expand business in overseas markets have increased since the export of a nuclear power plant to UAE in 2009. In this study, we use PDCA method to systematically analyze the quality assurance procedures that were used in previous projects for constructing nuclear power plants. We reached a classification system of quality assurance processes at each phase of nuclear power plant construction by integrating similar work related to quality such as planning, design, equipment manufacturing, construction and start-up. We also established a hierarchy of quality assurance processes to develop an integrated quality assurance system as a technology goal to be developed later. To obtain most updated quality assurance activities, a quality assurance process is structured by integrating similar works analyzed from quality assurance procedures through PDCA cycle method. At the implementation phase of Hierarchy of quality processes and sequence of processes for constructing nuclear power plant are established in this study. Integrated quality assurance system is to be developed by connecting organizations as well as stakeholders such as owners, Architect engineering, suppliers, contractors, and sub-contractors to carry out assigned work efficiently.
Impact of power generation on air quality

International Nuclear Information System (INIS)

Fisher, B.E.A.

1999-01-01

The article discusses the impact of the electric power industry on air quality. Much of the data are presented in chronological order starting with the London smogs in the late nineteenth century and the Clean Air Act of 1956. With the building of bigger and bigger coal-fired power stations, apparatus to restrict emissions of dust became common and a Royal Commission reported on the progress of smoke control in 1974 and 1976. The article is presented under the sub-headings of (i) role of Local Authorities; (ii) weather and smog; (iii) trends in emissions; (iv) dispersal and dilution; (v) smoke and sulfur dioxide exported; (vi) atmospheric lifetime of sulfur dioxide; (vii) proportionality between emissions and deposition; (viii) critical loads; (ix) international agreements on transboundary pollution; (x) road transport pollution; (xi) local air quality management and (xii) climate change
Management of Power Quality Issues in Low Voltage Networks using Electric Vehicles: Experimental Validation

DEFF Research Database (Denmark)

Martinenas, Sergejus; Knezovic, Katarina; Marinelli, Mattia

2017-01-01

the existing and future power quality problems. One of the main aspects of the power quality relates to voltage quality. The aim of this work is to experimentally analyse whether series-produced EVs, adhering to contemporary standard and without relying on any V2G capability, can mitigate line voltage drops...... in improving the power quality of a highly unbalanced grid...

Quality assurance program for isotopic power systems

International Nuclear Information System (INIS)

Hannigan, R.L.; Harnar, R.R.

1982-12-01

This report summarizes the Sandia National Laboratories Quality Assurance Program that applies to non-weapon (reimbursable) Radioisotopic Thermoelectric Generators. The program has been implemented over the past 16 years on power supplies used in various space and terrestrial systems. The quality assurance (QA) activity of the program is in support of the Department of Energy, Office of Space Nuclear Projects. Basic elements of the program are described in the report and examples of program decumentation are presented
Quality assurance program for isotopic power systems

Energy Technology Data Exchange (ETDEWEB)

Hannigan, R.L.; Harnar, R.R.

1982-12-01

This report summarizes the Sandia National Laboratories Quality Assurance Program that applies to non-weapon (reimbursable) Radioisotopic Thermoelectric Generators. The program has been implemented over the past 16 years on power supplies used in various space and terrestrial systems. The quality assurance (QA) activity of the program is in support of the Department of Energy, Office of Space Nuclear Projects. Basic elements of the program are described in the report and examples of program decumentation are presented.
PROVIDING QUALITY OF ELECTRIC POWER IN ELECTRIC POWER SYSTEM IN PARALLEL OPERATION WITH WIND TURBINE

Directory of Open Access Journals (Sweden)

Yu. A. Rolik

2016-01-01

Full Text Available The problem of providing electric power quality in the electric power systems (EPS that are equipped with sufficiently long air or cable transmission lines is under consideration. This problem proved to be of particular relevance to the EPS in which a source of electrical energy is the generator of wind turbines since the wind itself is an instable primary energy source. Determination of the degree of automation of voltage regulation in the EPS is reduced to the choice of methods and means of regulation of power quality parameters. The concept of a voltage loss and the causes of the latter are explained by the simplest power system that is presented by a single-line diagram. It is suggested to regulate voltage by means of changing parameters of the network with the use of the method of reducing loss of line voltage by reducing its reactance. The latter is achieved by longitudinal capacitive compensation of the inductive reactance of the line. The effect is illustrated by vector diagrams of currents and voltages in the equivalent circuits of transmission lines with and without the use of longitudinal capacitive compensation. The analysis of adduced formulas demonstrated that the use of this method of regulation is useful only in the systems of power supply with a relatively low power factor (cosφ < 0.7 to 0.9. This power factor is typical for the situation of inclusion the wind turbine with asynchronous generator in the network since the speed of wind is instable. The voltage regulation fulfilled with the aid of the proposed method will make it possible to provide the required quality of the consumers’ busbars voltage in this situation. In is turn, it will make possible to create the necessary conditions for the economical transmission of electric power with the lowest outlay of reactive power and the lowest outlay of active power losses.
Quantifying spatial heterogeneity from images

International Nuclear Information System (INIS)

Pomerantz, Andrew E; Song Yiqiao

2008-01-01

Visualization techniques are extremely useful for characterizing natural materials with complex spatial structure. Although many powerful imaging modalities exist, simple display of the images often does not convey the underlying spatial structure. Instead, quantitative image analysis can extract the most important features of the imaged object in a manner that is easier to comprehend and to compare from sample to sample. This paper describes the formulation of the heterogeneity spectrum to show the extent of spatial heterogeneity as a function of length scale for all length scales to which a particular measurement is sensitive. This technique is especially relevant for describing materials that simultaneously present spatial heterogeneity at multiple length scales. In this paper, the heterogeneity spectrum is applied for the first time to images from optical microscopy. The spectrum is measured for thin section images of complex carbonate rock cores showing heterogeneity at several length scales in the range 10-10 000 μm.
France ranked first for the quality of its electrical power

International Nuclear Information System (INIS)

Anon.

2013-01-01

France has been ranked first among 146 countries for the quality and availability of its electrical power by the Choiseul Institute and KMPG. This classification is made according to 3 categories: first, the quality of the energy mix, secondly quality and availability of the electrical power, and thirdly the environmental footprint. France ranks first for the second category because of its important fleet of nuclear reactors, but ranks 93 for the quality of its energy mix, its poor performance is due to its large dependence on oil as primary energy. The performance of France for the environment footprint is only in the world average for despite is low-carbon electricity production, French households release great quantities of CO 2 . (A.C.)
Adaptive neuro-fuzzy inference system to improve the power quality of a split shaft microturbine power generation system

Science.gov (United States)

Oğuz, Yüksel; Üstün, Seydi Vakkas; Yabanova, İsmail; Yumurtaci, Mehmet; Güney, İrfan

2012-01-01

This article presents design of adaptive neuro-fuzzy inference system (ANFIS) for the turbine speed control for purpose of improving the power quality of the power production system of a split shaft microturbine. To improve the operation performance of the microturbine power generation system (MTPGS) and to obtain the electrical output magnitudes in desired quality and value (terminal voltage, operation frequency, power drawn by consumer and production power), a controller depended on adaptive neuro-fuzzy inference system was designed. The MTPGS consists of the microturbine speed controller, a split shaft microturbine, cylindrical pole synchronous generator, excitation circuit and voltage regulator. Modeling of dynamic behavior of synchronous generator driver with a turbine and split shaft turbine was realized by using the Matlab/Simulink and SimPowerSystems in it. It is observed from the simulation results that with the microturbine speed control made with ANFIS, when the MTPGS is operated under various loading situations, the terminal voltage and frequency values of the system can be settled in desired operation values in a very short time without significant oscillation and electrical production power in desired quality can be obtained.
Qualification of quality assurance program audit personnel for nuclear power plants - August 1980

International Nuclear Information System (INIS)

Anon.

1981-01-01

Appendix B, Quality Assurance Criteria for Nuclear Power Plants and Fuel Reprocessing Plants, to 10 CFR Part 50, Domestic Licensing of Production and Utilization Facilities, establishes overall quality assurance requirements for the design, construction, and operation of safety-related structures, and components of nuclear power plants. Criterion XVIII, Audits, of Appendix B establishes requirements for conducting audits of the quality assurance program. This guide describes a method acceptable to the NRC staff for complying with the Commission's regulations with regard to qualification of quality assurance program audit personnel for nuclear power plants
Operations quality assurance for nuclear power plants

International Nuclear Information System (INIS)

1987-01-01

This standard covers the quality assurance of all activities concerned with the operation and maintenance of plant equipment and systems in CANDU-based nuclear power plants during the operations phase, the period between the completion of commissioning and the start of decommissioning
Research on quality assurance classification methodology for domestic AP1000 nuclear power projects

International Nuclear Information System (INIS)

Bai Jinhua; Jiang Huijie; Li Jingyan

2012-01-01

To meet the quality assurance classification requirements of domestic nuclear safety codes and standards, this paper analyzes the quality assurance classification methodology of domestic AP1000 nuclear power projects at present, and proposes the quality assurance classification methodology for subsequent AP1000 nuclear power projects. (authors)
Coordinated Energy Management in Heterogeneous Processors

Directory of Open Access Journals (Sweden)

Indrani Paul

2014-01-01

Full Text Available This paper examines energy management in a heterogeneous processor consisting of an integrated CPU–GPU for high-performance computing (HPC applications. Energy management for HPC applications is challenged by their uncompromising performance requirements and complicated by the need for coordinating energy management across distinct core types – a new and less understood problem. We examine the intra-node CPU–GPU frequency sensitivity of HPC applications on tightly coupled CPU–GPU architectures as the first step in understanding power and performance optimization for a heterogeneous multi-node HPC system. The insights from this analysis form the basis of a coordinated energy management scheme, called DynaCo, for integrated CPU–GPU architectures. We implement DynaCo on a modern heterogeneous processor and compare its performance to a state-of-the-art power- and performance-management algorithm. DynaCo improves measured average energy-delay squared (ED2 product by up to 30% with less than 2% average performance loss across several exascale and other HPC workloads.
Power quality control of an autonomous wind-diesel power system based on hybrid intelligent controller.

Science.gov (United States)

Ko, Hee-Sang; Lee, Kwang Y; Kang, Min-Jae; Kim, Ho-Chan

2008-12-01

Wind power generation is gaining popularity as the power industry in the world is moving toward more liberalized trade of energy along with public concerns of more environmentally friendly mode of electricity generation. The weakness of wind power generation is its dependence on nature-the power output varies in quite a wide range due to the change of wind speed, which is difficult to model and predict. The excess fluctuation of power output and voltages can influence negatively the quality of electricity in the distribution system connected to the wind power generation plant. In this paper, the authors propose an intelligent adaptive system to control the output of a wind power generation plant to maintain the quality of electricity in the distribution system. The target wind generator is a cost-effective induction generator, while the plant is equipped with a small capacity energy storage based on conventional batteries, heater load for co-generation and braking, and a voltage smoothing device such as a static Var compensator (SVC). Fuzzy logic controller provides a flexible controller covering a wide range of energy/voltage compensation. A neural network inverse model is designed to provide compensating control amount for a system. The system can be optimized to cope with the fluctuating market-based electricity price conditions to lower the cost of electricity consumption or to maximize the power sales opportunities from the wind generation plant.
Distributed generation system with PEM fuel cell for electrical power quality improvement

Energy Technology Data Exchange (ETDEWEB)

Ramirez, D.; Beites, L.F.; Blazquez, F. [Department of Electrical Engineering, ETSII, Escuela de Ingenieros Industriales, Universidad Politecnica de Madrid, C/ Jose Gutierrez Abascal 2, 28006 Madrid (Spain); Ballesteros, J.C. [Endesa Generacion, S.A. c/ Ribera de Loira 60, 28042 Madrid (Spain)

2008-08-15

In this paper, a physical model for a distributed generation (DG) system with power quality improvement capability is presented. The generating system consists of a 5 kW PEM fuel cell, a natural gas reformer, hydrogen storage bottles and a bank of ultra-capacitors. Additional power quality functions are implemented with a vector-controlled electronic converter for regulating the injected power. The capabilities of the system were experimentally tested on a scaled electrical network. It is composed of different lines, built with linear inductances and resistances, and taking into account both linear and non-linear loads. The ability to improve power quality was tested by means of different voltage and frequency perturbations produced on the physical model electrical network. (author)
Biological indices for classification of water quality around Mae Moh power plant, Thailand

Directory of Open Access Journals (Sweden)

Pongsarun Junshum and Siripen Traichaiyaporn

2007-12-01

Full Text Available The algal communities and water quality were monitored at eight sampling sites around Mae Moh power plant during January-December 2003. Three biological indices, viz. algal genus pollution index, saprobic index, and Shannon-Weaver index, were adopted to classify the water quality around the power plant in comparison with the measured physico-chemical water quality. The result shows that the Shannon-Weaver diversity index appears to be much more applicable and interpretable for the classification of water quality around the Mae Moh power plant than the algal genus pollution index and the saprobic index.
Heterogeneous Computing in Economics

DEFF Research Database (Denmark)

Dziubinski, M.P.; Grassi, S.

2014-01-01

This paper shows the potential of heterogeneous computing in solving dynamic equilibrium models in economics. We illustrate the power and simplicity of C++ Accelerated Massive Parallelism (C++ AMP) recently introduced by Microsoft. Starting from the same exercise as Aldrich et al. (J Econ Dyn...
Scales of heterogeneity of water quality in rivers: Insights from high resolution maps based on integrated geospatial, sensor and ROV technologies

Science.gov (United States)

While the spatial heterogeneity of many aquatic ecosystems is acknowledged, rivers are often mistakenly described as homogenous and well-mixed. The collection and visualization of attributes like water quality is key to our perception and management of these ecosystems. The ass...
Power Quality Experimental Analysis on Rural Home Grid-Connected PV Systems

Directory of Open Access Journals (Sweden)

Rita Jorge Cerqueira Pinto

2015-01-01

Full Text Available Microgeneration is the small-scale generation of heat or electric power or both, by individuals or buildings to meet their own needs. Recently, microgeneration is being regarded as a means to decentralize the power production of renewable energies, reducing the impacts on the grid caused by unexpected energy demands. Given the increase in microgeneration facilities, determining the quantity of energy produced and the power quality assumes growing importance in low, medium, or high voltage facilities. This paper presents a power quality analysis of two different facilities with photovoltaic generation localized in a rural area of Portugal, describing the voltage and frequency behaviour, the harmonic contents, and the total harmonic distortion. Statistical data are presented regarding the number of voltage events and occurrence of dips and swells in both facilities as a percentage of rated voltage. We conclude that some PV systems can severely affect voltage quality, forcing the grid to work at and even above the maximum voltage standard limit.
Heterogeneity of sleep quality in relation to circadian preferences and depressive symptomatology among major depressive patients.

Science.gov (United States)

Selvi, Yavuz; Boysan, Murat; Kandeger, Ali; Uygur, Omer F; Sayin, Ayca A; Akbaba, Nursel; Koc, Basak

2018-08-01

The current study aimed at investigating the latent dimensional structure of sleep quality as indexed by the seven components of the Pittsburgh Sleep Quality Index (PSQI), as well as latent covariance structure between sleep quality, circadian preferences and depressive symptoms. Two hundred twenty-five patients with major depressive disorder (MDD), with an average age of 29.92 ± 10.49 years (aged between 17 and 63), participated in the study. The PSQI, Morningness-Eveningness Questionnaire (MEQ) and Beck Depression Inventory (BDI) were administered to participants. Four sets of latent class analyses were subsequently run to obtain optimal number of latent classes best fit to the data. Mixture models revealed that sleep quality is multifaceted in MDD. The data best fit to four-latent-class model: Poor Habitual Sleep Quality (PHSQ), Poor Subjective Sleep Quality (PSSQ), Intermediate Sleep Quality (ISQ), and Good Sleep Quality (GSQ). MDD patients classified into GSQ latent class (23.6%) reported the lowest depressive symptoms and were more prone to morningness diurnal preferences compared to other three homogenous sub-groups. Finally, the significant association between eveningness diurnal preferences and depressive symptomatology was significantly mediated by poor sleep quality. The cross-sectional nature of the study and the lack of an objective measurement of sleep such as polysomnography recordings was the most striking limitation of the study. We concluded sleep quality in relation to circadian preferences and depressive symptoms has a heterogeneous nature in MDD. Copyright © 2018. Published by Elsevier B.V.
Quality of the current low power and shutdown PSA practice

International Nuclear Information System (INIS)

Jang, Seung Cheol; Park, Jin Hee; Lim, Ho Gon; Kim, Tae Woon

2004-01-01

A probabilistic safety assessment (PSA) for the low-power and shutdown (LPSD) modes in a Korea standard nuclear power plant (KSNP) has been performed for the purpose of estimating the LPSD risk and identifying the vulnerabilities of LPSD operations. Both the operational experience and PSA results indicate that the risks from LPSD operations could be comparable with those from power operations. However, the application of the LPSD risk insights to risk-informed decision making has been slow to be adopted in practice. It is largely due to the question of whether the current LPSD PSA practice is appropriate for application to risk-informed decision making or not. Such a question has to do with the quality of the current LPSD PSA practice. In this paper, we have performed self-assessment of the KSNP LPSD PSA quality based on the ANS Standard (draft as of 13 Sep. 2002). The aims of the work are to find the LPSD PSA technical areas insufficient for application to risk-informed decision making and to efficiently allocate the limited research resources to improve the LPSD PSA model quality. Many useful findings regarding the current LPSD PSA quality are presented in this paper
Thoughts about quality assurance during Electricite de France nuclear power plant operation

International Nuclear Information System (INIS)

Feger, M.

1975-01-01

Thinking on the operating quality guarantee is presented from the experience acquired in the last 11 years of French nuclear power station operation and from what it is known about power stations abroad (regulation aspect of the problem, reduction in human errors and their consequences, personnel qualification, working methods, quality control). The organization used now in the Fessenheim power station which must go into service at the end of 1975 is explained [fr
Quality assurance during the manufacture of nuclear power plant components

International Nuclear Information System (INIS)

Mueller, J.

1976-01-01

Apart from the special requirements of quality assurance in the production of components for the nuclear industry, in particular nuclear power stations, the author discusses special methods of quality control in the testing of welded joints. (TK) [de

Quality assurance in the structural installations of nuclear power stations

International Nuclear Information System (INIS)

Schnellenbach, G.; Wrage, S.

1985-01-01

The concept of quality assurance distinguishes between self-monitoring of the design, manufacturing and executing firms and external monitoring by state institutions or by experts commissioned by them. The long-term control of structures is within the area of responsibility of the owner. This quality assurance concept is controlled in detail by statutes, which clearly define responsibilities. This structural engineering quality assurance system also forms the basis for the design, construction and utilization of structural installations of nuclear power stations; requirements emanating from the Atomic Energy Acts for the structural installations demand, however, to some extent a sharpening of self- and external monitoring. Therefore, today a quality concept has been developed for the important engineering safety-related buildings of nuclear power stations. This concept takes account of the strict requirements imposed and fulfils the requirement of KTA 1401. (orig.) [de
Power quality on campus

Energy Technology Data Exchange (ETDEWEB)

Copper Development Association

2011-05-15

The Maria Stata Center on the campus of the Massachusetts Institute of Technology (MIT) is home to the Computer Science and Artificial Intelligence Laboratory (CSAIL), the Laboratory for Information and Decision Systems (LIDS) and the Department of Linguistics and Philosophy. Computers and networks are everywhere on campus and the electrical infrastructure, mainly made of copper, ensures the highest level of power quality. The copper-based grounding system helps stabilize the wiring system and several K-rated transformers help accommodate harmonic currents and improve energy efficiency. Separation from sensitive and non-sensitive branch circuits helps to shield sensitive equipment from electrical noise, and the installation of transient voltage surge suppression equipment assures maximum protection from voltage surges. .
Homogeneous and Heterogeneous MPSoC Architectures with Network-On-Chip Connectivity for Low-Power and Real-Time Multimedia Signal Processing

Directory of Open Access Journals (Sweden)

Sergio Saponara

2012-01-01

Full Text Available Two multiprocessor system-on-chip (MPSoC architectures are proposed and compared in the paper with reference to audio and video processing applications. One architecture exploits a homogeneous topology; it consists of 8 identical tiles, each made of a 32-bit RISC core enhanced by a 64-bit DSP coprocessor with local memory. The other MPSoC architecture exploits a heterogeneous-tile topology with on-chip distributed memory resources; the tiles act as application specific processors supporting a different class of algorithms. In both architectures, the multiple tiles are interconnected by a network-on-chip (NoC infrastructure, through network interfaces and routers, which allows parallel operations of the multiple tiles. The functional performances and the implementation complexity of the NoC-based MPSoC architectures are assessed by synthesis results in submicron CMOS technology. Among the large set of supported algorithms, two case studies are considered: the real-time implementation of an H.264/MPEG AVC video codec and of a low-distortion digital audio amplifier. The heterogeneous architecture ensures a higher power efficiency and a smaller area occupation and is more suited for low-power multimedia processing, such as in mobile devices. The homogeneous scheme allows for a higher flexibility and easier system scalability and is more suited for general-purpose DSP tasks in power-supplied devices.
Modelling firm heterogeneity with spatial 'trends'

Energy Technology Data Exchange (ETDEWEB)

Sarmiento, C. [North Dakota State University, Fargo, ND (United States). Dept. of Agricultural Business & Applied Economics

2004-04-15

The hypothesis underlying this article is that firm heterogeneity can be captured by spatial characteristics of the firm (similar to the inclusion of a time trend in time series models). The hypothesis is examined in the context of modelling electric generation by coal powered plants in the presence of firm heterogeneity.
Capacity and reliability analyses with applications to power quality

Science.gov (United States)

Azam, Mohammad; Tu, Fang; Shlapak, Yuri; Kirubarajan, Thiagalingam; Pattipati, Krishna R.; Karanam, Rajaiah

2001-07-01

The deregulation of energy markets, the ongoing advances in communication networks, the proliferation of intelligent metering and protective power devices, and the standardization of software/hardware interfaces are creating a dramatic shift in the way facilities acquire and utilize information about their power usage. The currently available power management systems gather a vast amount of information in the form of power usage, voltages, currents, and their time-dependent waveforms from a variety of devices (for example, circuit breakers, transformers, energy and power quality meters, protective relays, programmable logic controllers, motor control centers). What is lacking is an information processing and decision support infrastructure to harness this voluminous information into usable operational and management knowledge to handle the health of their equipment and power quality, minimize downtime and outages, and to optimize operations to improve productivity. This paper considers the problem of evaluating the capacity and reliability analyses of power systems with very high availability requirements (e.g., systems providing energy to data centers and communication networks with desired availability of up to 0.9999999). The real-time capacity and margin analysis helps operators to plan for additional loads and to schedule repair/replacement activities. The reliability analysis, based on computationally efficient sum of disjoint products, enables analysts to decide the optimum levels of redundancy, aids operators in prioritizing the maintenance options for a given budget and monitoring the system for capacity margin. The resulting analytical and software tool is demonstrated on a sample data center.
Purchasing and supply quality management in a power plant : a case study

OpenAIRE

2012-01-01

M. Ing. This research study aims at presenting the management of quality problem issues that often result from procured items in a power plant. The motivation for carrying out this research was an unacceptable risk of undesirable impact on plant availability, or operating costs that arises from quality problem issues of procured items in a particular power plant. In this dissertation, the author aims to provide an overview of quality management and procurement management, by focusing on ho...
Marker Protein Expression Combined With Expression Heterogeneity is a Powerful Indicator of Malignancy in Acral Lentiginous Melanomas.

Science.gov (United States)

Cintra Lopes Carapeto, Fernando; Neves Comodo, Andréia; Germano, Andressa; Pereira Guimarães, Daiane; Barcelos, Denise; Fernandes, Mariana; Landman, Gilles

2017-02-01

Samples of acral lentiginous melanomas (ALMs) were obtained from the Department of Pathology at Escola Paulista de Medicina-Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil. Demographic, clinical, and follow-up data were obtained from the charts of Hospital São Paulo. From 2 tissue microarrays containing 60 nevi and quadruplicate samples of ≥1.0-mm of 49 ALM, sections were stained to evaluate SCF, KIT, BRAF, CYCLIND1, MYC, and PTEN immunohistochemical protein expression. Nevi and ALM from 2006 to 2010 were reviewed and collected. All specimens were in the vertical growth phase, and histopathological parameters indicated that tumors were at an advanced stage at diagnosis. Average tumor thickness was 6.95 mm, 63% were ulcerated, average mitotic index was 5 mitotic cells per mm, and 43% were at Clark's level V. Compared with nevi, the χ test showed that ALM significantly correlated with SCF protein expression (P = 0.001) and expression heterogeneity (P < 0.000). Similar findings were observed for KIT (P = 0.005, P = 0.003, respectively), MYC (P < 0.000, P < 0.000), and PTEN (P = 0.005, P < 0.000). Malignancy did not correlate with BRAF and CYCLIN D1 expression (P = 0.053 and P = 0.259, respectively), but it did significantly correlate with their heterogeneous expression (P < 0.000, P = 0.024, respectively). Combined protein expression had an odds ratio of greater malignancy when BRAF and MYC were positive and/or heterogeneously expressed (OR of 78 and 95, respectively). We show that marker protein expression, when combined with heterogeneous expression as shown by immunohistochemistry, is a powerful indicator of malignancy in ALMs, especially, when protein pairs are combined.
Quality assurance in the procurement of items and services for nuclear power plants

International Nuclear Information System (INIS)

1979-01-01

This Safety Guide was prepared as part of the Agency's programme, referred to as the NUSS programme, for establishing Codes of Practice and Safety Guides relating to nuclear power plants. It supplements the Agency's Code of Practice on Quality Assurance for Safety in Nuclear Power Plants (Safety Series No.50-C-QA), which states requirements for the control of procurement of items and services which are important to the safety of nuclear power plants, for the purpose of achieving quality. The establishment and implementation of controls over the procurement process provide a basis for establishing an appropriate level of confidence that the activities undertaken during procurement of items and services have been performed in accordance with the principles of quality assurance expressed in the Code, and that the required quality of items and services has been achieved. The purchaser, in establishing control over procurement, shall ensure that the quality criteria, quality level, and other quality requirements specified for the particular item or service are taken into account
Modeling a Distributed Power Flow Controller with a PEM Fuel Cell for Power Quality Improvement

Directory of Open Access Journals (Sweden)

J. Chakravorty

2018-02-01

Full Text Available Electrical power demand is increasing at a relatively fast rate over the last years. Because of this increasing demand the power system is becoming very complex. Both electric utilities and end users of electric power are becoming increasingly concerned about power quality. This paper presents a new concept of distributed power flow controller (DPFC, which has been implemented with a proton exchange membrane (PEM fuel cell. In this paper, a PEM fuel cell has been simulated in Simulink/MATLAB and then has been used in the proposed DPFC model. The new proposed DPFC model has been tested on a IEEE 30 bus system.
Management quality in spanish nuclear power plant operation

International Nuclear Information System (INIS)

Perez de Zabalza Ramos, F.

1995-01-01

This paper analyzes the reasons that lead nuclear power plants to require engineering support that is not usual in other types of industrial installations, namely the complexity of the plant and the economic consequences of a possible shutdown. At the time of unit startup, the need to use the services of experienced engineers for the technical support of nuclear power plants induced plant owners to turn to the engineering companies which had participated in the design of the plants. The paper lists the wide range of plant support services which these engineering companies can provide, both from their central offices and on site, especially in the field of change orders and documentation update. The paper also describes the satisfactory development of management parameters in Spanish nuclear power plants both in terms of load factor and comparison of operating and maintenance costs, and how engineering companies have contributed to this achievement, by reducing costs with no loss in the technical quality of their services. Finally, the paper describes how the engineering companies have had to adapt to a shrinking market without losing quality and how they achieved this by diversifying their services. In this context there are two areas of concern. the first area of concern is the competition from certain companies with oversized staff, who attempt to employ them in operation support for nuclear power stations, a field which does not correspond to the training and background of said staff. This could lead to a loss of quality or economic efficiency of nuclear power plants, whose operation up to now has proven satisfactory. The second area of concern is the operator's tendency to use their own resources for engineering support, making more difficult the renewal of human resources and thus leading to a decrease in productivity, and in the transfer of practical and theoretical experience from one plant to another, as well as in the transmission of the latest know
Review of FACTS technologies and applications for power quality in smart grids with renewable energy systems

DEFF Research Database (Denmark)

Gandoman, Foad H.; Ahmadi, Abdollah; Sharaf, Adel M.

2018-01-01

In the last two decades, emerging use of renewable and distributed energy sources in electricity grid has created new challenges for the utility regarding the power quality, voltage stabilization and efficient energy utilization. Power electronic converters are extensively utilized to interface...... the power quality. Also, distributed FACTSs play an important role in improving the power factor, energy utilization, enhancing the power quality, and ensuring efficient energy utilization and energy management in smart grids with renewable energy sources. This paper presents a literature survey of FACTS...... technology tools and applications for power quality and efficient renewable energy system utilization....
Exploring heterogeneous market hypothesis using realized volatility

Science.gov (United States)

Chin, Wen Cheong; Isa, Zaidi; Mohd Nor, Abu Hassan Shaari

2013-04-01

This study investigates the heterogeneous market hypothesis using high frequency data. The cascaded heterogeneous trading activities with different time durations are modelled by the heterogeneous autoregressive framework. The empirical study indicated the presence of long memory behaviour and predictability elements in the financial time series which supported heterogeneous market hypothesis. Besides the common sum-of-square intraday realized volatility, we also advocated two power variation realized volatilities in forecast evaluation and risk measurement in order to overcome the possible abrupt jumps during the credit crisis. Finally, the empirical results are used in determining the market risk using the value-at-risk approach. The findings of this study have implications for informationally market efficiency analysis, portfolio strategies and risk managements.
The contribution of quality assurance to safety and reliability in nuclear power plants

International Nuclear Information System (INIS)

Raisic, N.

1978-01-01

The potential contribution of quality assurance to nuclear power plant safety and reliability is analysed. An attempt is made to establish a relationship between quality and reliability. The reliability may be expressed in quantitative terms as ''the probability that an item will perform a required function for a stated period of time''. Quality, however, cannot be expressed in simple quantitative terms but only as a set of required properties which an item should have for a specific application. The achievement of quality and additional reliability objectives is a task of project activities such as design, construction, installation, operation, etc. The elements of a quality assurance system and its functions in nuclear power projects are presented in some detail. Confidence in plant quality, which should be a basis for the regulatory body issuing the construction permit or operation licence, should be based on the capability of quality assurance activities to prevent errors and correct deficiencies in nuclear power plants. An analysis is made of those errors in plant design, manufacture, construction and operation which contribute most frequently to plant outages. It is concluded that these errors can be avoided or corrected by strict adherence to quality assurance principles and by the efficient functioning of quality assurance systems. In fact, quality assurance may be considered an effective defence against common cause failures originating in errors in the design, manufacture, installation or operation of a nuclear power plant
Evaluating perceived quality of CELPE service: A Brazilian power company case study

International Nuclear Information System (INIS)

Paes de Barros Filho, Joao; Fritsch Damasio da Silva, Cleriston; Nascimento Melo, Maria Auxiliadora do; Dumke de Medeiros, Denise

2009-01-01

This paper presents an application of a methodology for the diagnosis and analysis of the service quality perceived by a Particular Group of CELPE Corporate Customers, a Brazilian power company at Pernambuco State. Concepts, on the power sector, of Quality in Services, Performance Objectives and Critical Factors of Success have been used to develop the analysis. Next, the Critical Factors for a power company were determined and classified in accordance with the performance objectives: Quality, Dependability, Speed and Flexibility. From the factors established, a questionnaire was created to collect data. The case studied involves quantitative research on CELPE's private corporate principal customers using statistical tests to measure internal consistency reliability of the questionnaire scales and to identify underlying concepts, in the four groups analyzed, through which the private corporate customers perceive quality in the given services. Among the goals of this study are to improve the relationship with principal Private Corporate Clients, to create customer loyalty, and to maximize efforts in providing the power supply service, all of them with a view to improving and determining the Global Satisfaction Index
Evaluating perceived quality of CELPE service: A Brazilian power company case study

Energy Technology Data Exchange (ETDEWEB)

Paes de Barros Filho, Joao [Federal University of Pernambuco (UFPE), Center of Technology and Geosciences, 5th floor, Academico Helio Ramos av., Cidade Universitaria, Recife, PE 50.670-901 (Brazil)], E-mail: joaopaes@celpe.com.br; Fritsch Damasio da Silva, Cleriston [Federal University of Pernambuco (UFPE), Center of Technology and Geosciences, 5th floor, Academico Helio Ramos av., Cidade Universitaria, Recife, PE 50.670-901 (Brazil)], E-mail: cleriston_silva@yahoo.com.br; Nascimento Melo, Maria Auxiliadora do [Federal University of Pernambuco (UFPE), Center of Technology and Geosciences, 5th floor, Academico Helio Ramos av., Cidade Universitaria, Recife, PE 50.670-901 (Brazil)], E-mail: manmelo@ufpe.br; Dumke de Medeiros, Denise [Federal University of Pernambuco (UFPE), Center of Technology and Geosciences, 5th floor, Academico Helio Ramos av., Cidade Universitaria, Recife, PE 50.670-901 (Brazil)], E-mail: ddm@ufpe.br

2009-04-15

This paper presents an application of a methodology for the diagnosis and analysis of the service quality perceived by a Particular Group of CELPE Corporate Customers, a Brazilian power company at Pernambuco State. Concepts, on the power sector, of Quality in Services, Performance Objectives and Critical Factors of Success have been used to develop the analysis. Next, the Critical Factors for a power company were determined and classified in accordance with the performance objectives: Quality, Dependability, Speed and Flexibility. From the factors established, a questionnaire was created to collect data. The case studied involves quantitative research on CELPE's private corporate principal customers using statistical tests to measure internal consistency reliability of the questionnaire scales and to identify underlying concepts, in the four groups analyzed, through which the private corporate customers perceive quality in the given services. Among the goals of this study are to improve the relationship with principal Private Corporate Clients, to create customer loyalty, and to maximize efforts in providing the power supply service, all of them with a view to improving and determining the Global Satisfaction Index.
Evaluating perceived quality of CELPE service. A Brazilian power company case study

Energy Technology Data Exchange (ETDEWEB)

De Barros Filho, Joao Paes; Da Silva, Cleriston Fritsch Damasio; Do Nascimento Melo, Maria Auxiliadora; De Medeiros, Denise Dumke [Federal University of Pernambuco (UFPE), Center of Technology and Geosciences, 5th floor, Academico Helio Ramos av., Cidade Universitaria, Recife, PE 50.670-901 (Brazil)

2009-04-15

This paper presents an application of a methodology for the diagnosis and analysis of the service quality perceived by a Particular Group of CELPE Corporate Customers, a Brazilian power company at Pernambuco State. Concepts, on the power sector, of Quality in Services, Performance Objectives and Critical Factors of Success have been used to develop the analysis. Next, the Critical Factors for a power company were determined and classified in accordance with the performance objectives: Quality, Dependability, Speed and Flexibility. From the factors established, a questionnaire was created to collect data. The case studied involves quantitative research on CELPE's private corporate principal customers using statistical tests to measure internal consistency reliability of the questionnaire scales and to identify underlying concepts, in the four groups analyzed, through which the private corporate customers perceive quality in the given services. Among the goals of this study are to improve the relationship with principal Private Corporate Clients, to create customer loyalty, and to maximize efforts in providing the power supply service, all of them with a view to improving and determining the Global Satisfaction Index. (author)
Power infrastructure quality and manufacturing productivity in Africa: A firm level analysis

International Nuclear Information System (INIS)

Moyo, Busani

2013-01-01

This study sought to examine the impact of the quality of power infrastructure on productivity in African manufacturing firms using data from the World Bank enterprise surveys. We measured power infrastructure quality using the number of hours per day without electricity and the percentage of output lost due to outages and found these indicators to be negative and significant determinants of productivity. These variables seem to be significant determinants in Uganda, Tanzania and Zambia as well as in the food and agriculture sector. To improve economic growth and encourage employment creation, governments in Africa have to come up with measures to improve the reliability of electricity infrastructure. - Highlights: • Power infrastructure quality indicators are found to have a negative and significant effect. • The power quality indicators have varied effects both at country and sector level. • Owning a generator minimises the negative impact of outages in Uganda, Tanzania and Mauritius. • Other controls like labour, capital, foreign ownership etc. have a positive and significant effect. • The firm age variable is insignificant suggesting that accumulated knowledge does not matter
Auditing of quality assurance programs for nuclear power plants - September 1980 - (Rev.1)

International Nuclear Information System (INIS)

Anon.

1981-01-01

Appendix B, Quality Assurance Criteria for Nuclear Power Plants and Fuel Reprocessing Plants, to 10 CFR Part 50, Domestic Licensing of Production and Utilization Facilities, establishes overall quality assurance requirements for the design, construction, and operation of structures, systems, and components of nuclear power plants important to safety. Criterion XVIII, Audits, of Appendix B to 10 CFR Part 50 establishes requirements for conducting audits of the quality assurance program. This guide describes a method acceptable to the NRC staff for complying with the Commission's regulations with regard to auditing of quality assurance programs for nuclear power plants. The Advisory Committee on Reactor Safeguards has been consulted concerning this guide and has concurred in the regulatory position
Quality control and assurance in building the Dukovany nuclear power plant - check on and filing of quality certificates

International Nuclear Information System (INIS)

Sokola, J.

1986-01-01

The following documents were used for determining the range of documentation required for the construction of the Dukovany nuclear power plant: the decree valid in Czechoslovakia for all industrial structures, the respective Czechoslovak State and branch standards and several special Soviet regulations. For the central recording of all documents on the quality of deliveries and assemblies a special quality assurance unit was set up on the site of the nuclear power plant. In the system of the flow of documents on the quality of the structure of the Dukovany nuclear power plant there are 16 addressees, from outside subcontractors to on-site managerial staff, work safety inspectors, etc., to the enterprise archives and the department of scientific and technical information. A brief description is presented of the different types of documents on the quality of deliveries and assemblies, and the method of inspection of their content and completeness is described. (Z.M.)
The EDEN-IW ontology model for sharing knowledge and water quality data between heterogenous databases

DEFF Research Database (Denmark)

Stjernholm, M.; Poslad, S.; Zuo, L.

2004-01-01

The Environmental Data Exchange Network for Inland Water (EDEN-IW) project's main aim is to develop a system for making disparate and heterogeneous databases of Inland Water quality more accessible to users. The core technology is based upon a combination of: ontological model to represent...... a Semantic Web based data model for IW; software agents as an infrastructure to share and reason about the IW se-mantic data model and XML to make the information accessible to Web portals and mainstream Web services. This presentation focuses on the Semantic Web or Onto-logical model. Currently, we have...

Quality control of stainless steel pipings for nuclear power generation

International Nuclear Information System (INIS)

Miki, Minoru; Kitamura, Ichiro; Ito, Hisao; Sasaki, Ryoichi

1979-01-01

The proportion of nuclear power in total power generation is increasing recently in order to avoid the concentrated dependence on petroleum resources, consequently the reliability of operation of nuclear power plants has become important. In order to improve the reliability of plants, the reliability of each machine or equipment must be improved, and for the purpose, the quality control at the time of manufacture is the important factor. The piping systems for BWRs are mostly made of carbon steel, and stainless steel pipings are used for the recirculation system cooling reactors and instrumentation system. Recently, grain boundary type stress corrosion cracking has occurred in the heat-affected zones of welded stainless steel pipings in some BWR plants. In this paper, the quality control of stainless steel pipings is described from the standpoint of preventing stress corrosion cracking in BWR plants. The pipings for nuclear power plants must have sufficient toughness so that the sudden rupture never occurs, and also sufficient corrosion resistance so that corrosion products do not raise the radioactivity level in reactors. The stress corrosion cracking occurred in SUS 304 pipings, the factors affecting the quality of stainless steel pipings, the working method which improves the corrosion resistance and welding control are explained. (Kako, I.)
Quality assurance in the manufacture of items for nuclear power plants

International Nuclear Information System (INIS)

1981-01-01

This Safety Guide provides requirements and recommendations related to the establishment and implementation of a quality assurance programme for those organizations involved in the manufacture of items affecting the safety of nuclear power plants. The quality-assurance-related functions of a manufacturer may include activities such as designing, purchasing, fabricating, handling, shipping, storing, cleaning, inspecting, testing, modifying, repairing and maintaining. It is not the aim of the present Guide, which supplements the above-mentioned Code of Practice, to provide rules related to the quality assurance programme for the design of items. Manufacturers that generate designs shall follow the requirements and recommendations contained in the Safety Guide on Quality Assurance in the Design of Nuclear Power Plants (IAEA Safety Series No. 50-SG-QA6). All these publications form part of the Agency's programme, referred to as the NUSS programme, for establishing Codes of Practice and Safety Guides relating to land-based stationary thermal neutron power plants. A Provisional List of NUSS Programme Titles will be found at the end of this publication
A Study on the Approach to Quality Management in Construction of Nuclear Power Plants

Energy Technology Data Exchange (ETDEWEB)

Pingish, Panupong [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of); Choi, Kwang Sik [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of)

2010-05-15

The quality of works and services in nuclear facilities are important aspect of public safety and environmental protection. In the general legal framework for the regulation of nuclear power plants of each country, the requirement which effectiveness, overall quality management programme be established should be present. The organization having overall responsibility for a nuclear power plant shall be responsible for the establishment and implementation of the overall quality management programme for that plant. The construction methods available for new nuclear power plants are generally the same as those used for other big construction projects. The construction stage of a nuclear power plant includes a multitude of activities affecting quality which are performed by various organizations with specific responsibilities assigned to them. At the present, the IAEA source materials have been changing some documents for supporting tendency in the nuclear technology likewise in term of quality assurance concept to quality management concept. The principle goal for quality management is achieved assurance and sustainable with nuclear safety. This system brings all the requirements for managing facilities and activities together by only one system
A Study on the Approach to Quality Management in Construction of Nuclear Power Plants

International Nuclear Information System (INIS)

Pingish, Panupong; Choi, Kwang Sik

2010-01-01

The quality of works and services in nuclear facilities are important aspect of public safety and environmental protection. In the general legal framework for the regulation of nuclear power plants of each country, the requirement which effectiveness, overall quality management programme be established should be present. The organization having overall responsibility for a nuclear power plant shall be responsible for the establishment and implementation of the overall quality management programme for that plant. The construction methods available for new nuclear power plants are generally the same as those used for other big construction projects. The construction stage of a nuclear power plant includes a multitude of activities affecting quality which are performed by various organizations with specific responsibilities assigned to them. At the present, the IAEA source materials have been changing some documents for supporting tendency in the nuclear technology likewise in term of quality assurance concept to quality management concept. The principle goal for quality management is achieved assurance and sustainable with nuclear safety. This system brings all the requirements for managing facilities and activities together by only one system
Safe protocols for generating power pulses with heterogeneous populations of thermostatically controlled loads

International Nuclear Information System (INIS)

Sinitsyn, Nikolai A.; Kundu, Soumya; Backhaus, Scott

2013-01-01

Highlights: ► Algorithms to produce useful load response from a heterogeneous group of TCLs. ► Generation of sharp power pulses without initiating any unwanted oscillation. ► Open-loop methods, not requiring any detailed system modeling. ► One-way, utility-to-consumer, communication. ► Potential use in secondary frequency regulation, generation-load balancing, etc. - Abstract: We explore methods to use thermostatically controlled loads (TCLs), such as water heaters and air conditioners, to provide ancillary services by assisting in balancing generation and load. We show that by adding simple imbedded instructions and a small amount of memory to temperature controllers of TCLs, it is possible to design open-loop control algorithms capable of creating short-term pulses of demand response without unwanted power oscillations associated with temporary synchronization of the TCL dynamics. By moving a small amount of intelligence to each of the end point TCL devices, we are able to leverage our knowledge of the time dynamics of TCLs to shape the demand response pulses for different power system applications. A significant benefit of our open-loop method is the reduction from two-way to one-way broadcast communication which also eliminates many basic consumer privacy issues. In this work, we focus on developing the algorithms to generate a set of fundamental pulse shapes that can subsequently be used to create demand response with arbitrary profiles. Demand response control methods, such as the one developed here, open the door to fast, nonperturbative control of large aggregations of TCLs
Quality assurance system in electric power companies in Japan, (2)

International Nuclear Information System (INIS)

Hamaguchi, Shun-ichi

1980-01-01

The organization for the quality assurance in nuclear power plants of Kansai Electric Power Co., Inc. is introduced. It is still in investigation stage what quality assurance (QA) organization and system is the best. The QA investigation project team was organized in the form directly supervised by the Office of President. The purpose of QA in operation is to maintain the functions of power plants in good condition over the lifetime of the power plants after starting the operation, and the QA is divided into the following five items: (1) running operation, (2) check-up and maintenance, (3) in-service testing and inspection, (4) regular inspection, (5) general application control. The purposes and works to be implemented for these items are listed in a table, and explained in detail. The quality control in regular inspection is described about 4 stages is purchase order and contract, design, construction, and adjusting operation. Also further improvement of QA in operating nuclear power plants by implementing the next items has been decided to make the most of the teachings in the accident of Three Mile Island plant. (1) Reinforcement of operation management system, (2) completion of the training for operators, (3) clarification of the command system for operational control, and (4) change of installations and review of application. As seen in the above description, the important tasks in QA activities are the matching to the existing installations and the adjustment of interfaces with the equipments in operation. (Wakatsuki, Y.)
Reconfiguring grid-interfacing converters for power quality improvement

NARCIS (Netherlands)

Wang, F.; Duarte, J.L.; Hendrix, M.A.M.; Encica, L.; Gysen, B.L.J.; Jansen, J.W.; Krop, D.C.J.

2008-01-01

In this paper reconfiguration of grid-interfacing converters is proposed for power quality improvement. In addition to the traditional function of delivering energy between distributed sources and the utility grid, more flexible ancillary functions can be integrated into the control of
Quality assurance during operation of nuclear power plants

International Nuclear Information System (INIS)

1981-01-01

This Safety Guide provides requirements and recommendations for the establishment and implementation of quality assurance for activities important to safety during commissioning, operation and decommissioning of a nuclear power plant, hereinafter referred to in this Guide as the operation phase or operation. It applies to activities such as: operating, inspecting, testing, commissioning, refuelling, maintaining, repairing, modifying and eventual shut-down and decommissioning of nuclear power plants. It applies also to associated activities related to safety, such as environmental monitoring and responses to emergencies
Voice over IP in Wireless Heterogeneous Networks

DEFF Research Database (Denmark)

Fathi, Hanane; Chakraborty, Shyam; Prasad, Ramjee

with the deployment of wireless heterogeneous systems, both speech and data traffic are carrried over wireless links by the same IP-based packet-switched infrastructure. However, this combination faces some challenges due to the inherent properties of the wireless network. The requirements for good quality VoIP...... communications are difficult to achieve in a time-varying environment due to channel errors and traffic congestion and across different systems. The provision of VoIP in wireless heterogeneous networks requires a set of time-efficient control mechanisms to support a VoIP session with acceptable quality....... The focus of Voice over IP in Wierless Heterogeneous Networks is on mechanisms that affect the VoIP user satisfaction while not explicitly involved in the media session. This relates to the extra delays introduced by the security and the signaling protocols used to set up an authorized VoIP session...
Household's willingness to pay for heterogeneous attributes of drinking water quality and services improvement: an application of choice experiment

Science.gov (United States)

Dauda, Suleiman Alhaji; Yacob, Mohd Rusli; Radam, Alias

2015-09-01

The service of providing good quality of drinking water can greatly improve the lives of the community and maintain a normal health standard. For a large number of population in the world, specifically in the developing countries, the availability of safe water for daily sustenance is none. Damaturu is the capital of Yobe State, Nigeria. It hosts a population of more than two hundred thousand, yet only 45 % of the households are connected to the network of Yobe State Water Corporation's pipe borne water services; this has led people to source for water from any available source and thus, exposed them to the danger of contracting waterborne diseases. In order to address the problem, Yobe State Government has embarked on the construction of a water treatment plant with a capacity and facility to improve the water quality and connect the town with water services network. The objectives of this study are to assess the households' demand preferences of the heterogeneous water attributes in Damaturu, and to estimate their marginal willingness to pay, using mixed logit model in comparison with conditional logit model. A survey of 300 households randomly sampled indicated that higher education greatly influenced the households' WTP decisions. The most significant variable from both of the models is TWQ, which is MRS that rates the water quality from the level of satisfactory to very good. 219 % in simple model is CLM, while 126 % is for the interaction model. As for MLM, 685 % is for the simple model and 572 % is for the interaction model. Estimate of MLM has more explanatory powers than CLM. Essentially, this finding can help the government in designing cost-effective management and efficient tariff structure.
Establishing the quality assurance programme for a nuclear power plant project

International Nuclear Information System (INIS)

1984-01-01

This Safety Guide provides requirements, recommendations and illustrative examples for establishing the overall quality assurance programme, and its constituent programmes, for a nuclear power plant project. It also provides guidance on the planning and documenting of programme plans and actions that are intended to ensure the achievement of the appropriate quality throughout the design, procurement, manufacture, construction, commissioning, operation and decommissioning of the nuclear power plant. The provisions of this Safety Guide are applicable to all organizations performing activities affecting the quality of items important to safety, such as designing, purchasing, fabricating, manufacturing, handling, shipping, storing, cleaning, erecting, installing, testing, commissioning, operating, inspecting, maintaining, repairing, refuelling, modifying and decommissioning
Power quality improvement of a stand-alone power system subjected to various disturbances

Science.gov (United States)

Lone, Shameem Ahmad; Mufti, Mairaj Ud-Din

In wind-diesel stand-alone power systems, the disturbances like random nature of wind power, turbulent wind, sudden changes in load demand and the wind park disconnection effect continuously the system voltage and frequency. The satisfactory operation of such a system is not an easy task and the control design has to take in to account all these subtleties. For maintaining the power quality, generally, a short-term energy storage device is used. In this paper, the performance of a wind-diesel system associated with a superconducting magnetic energy storage (SMES) system is studied. The effect of installing SMES at wind park bus/load bus, on the system performance is investigated. To control the exchange of real and reactive powers between the SMES unit and the wind-diesel system, a control strategy based on fuzzy logic is proposed. The dynamic models of the hybrid power system for most common scenarios are developed and the results presented.
Effects of physical and chemical heterogeneity on water-quality samples obtained from wells

Science.gov (United States)

Reilly, Thomas E.; Gibs, Jacob

1993-01-01

Factors that affect the mass of chemical constituents entering a well include the distributions of flow rate and chemical concentrations along and near the screened or open section of the well. Assuming a layered porous medium (with each layer being characterized by a uniform hydraulic conductivity and chemical concentration), a knowledge of the flow from each layer along the screened zone and of the chemical concentrations in each layer enables the total mass entering the well to be determined. Analyses of hypothetical systems and a site at Galloway, NJ, provide insight into the temporal variation of water-quality data observed when withdrawing water from screened wells in heterogeneous ground-water systems.The analyses of hypothetical systems quantitatively indicate the cause-and-effect relations that cause temporal variability in water samples obtained from wells. Chemical constituents that have relatively uniform concentrations with depth may not show variations in concentrations in the water discharged from a well after the well is purged (evacuation of standing water in the well casing). However, chemical constituents that do not have uniform concentrations near the screened interval of the well may show variations in concentrations in the well discharge water after purging because of the physics of ground-water flow in the vicinity of the screen.Water-quality samples were obtained through time over a 30 minute period from a site at Galloway, NJ. The water samples were analyzed for aromatic hydrocarbons, and the data for benzene, toluene, and meta+para xylene were evaluated for temporal variations. Samples were taken from seven discrete zones, and the flow-weighted concentrations of benzene, toluene, and meta+para xylene all indicate an increase in concentration over time during pumping. These observed trends in time were reproduced numerically based on the estimated concentration distribution in the aquifer and the flow rates from each zone.The results of
Heterogeneity of long-history migration predicts emotion recognition accuracy.

Science.gov (United States)

Wood, Adrienne; Rychlowska, Magdalena; Niedenthal, Paula M

2016-06-01

Recent work (Rychlowska et al., 2015) demonstrated the power of a relatively new cultural dimension, historical heterogeneity, in predicting cultural differences in the endorsement of emotion expression norms. Historical heterogeneity describes the number of source countries that have contributed to a country's present-day population over the last 500 years. People in cultures originating from a large number of source countries may have historically benefited from greater and clearer emotional expressivity, because they lacked a common language and well-established social norms. We therefore hypothesized that in addition to endorsing more expressive display rules, individuals from heterogeneous cultures will also produce facial expressions that are easier to recognize by people from other cultures. By reanalyzing cross-cultural emotion recognition data from 92 papers and 82 cultures, we show that emotion expressions of people from heterogeneous cultures are more easily recognized by observers from other cultures than are the expressions produced in homogeneous cultures. Heterogeneity influences expression recognition rates alongside the individualism-collectivism of the perceivers' culture, as more individualistic cultures were more accurate in emotion judgments than collectivistic cultures. This work reveals the present-day behavioral consequences of long-term historical migration patterns and demonstrates the predictive power of historical heterogeneity. (PsycINFO Database Record (c) 2016 APA, all rights reserved).
Trends, challenges and opportunities in power quality research

NARCIS (Netherlands)

Bollen, M.H.J.; Ribeiro, P.F.; Gu, I.Y.H.; Duque, C.A.

2009-01-01

This paper outlines a number of possible research directions in power quality. The introduction of new sources of generation will introduce the need for new research on voltage–magnitude variations, harmonic emission and harmonic resonance. Statistical performance indicators are expected to play an
How does litter quality and site heterogeneity interact on decomposer food webs of a semi-natural forest?

DEFF Research Database (Denmark)

Strandmark, Lisa Bjørnlund; Christensen, Søren

2005-01-01

The relative importance of litter quality and site heterogeneity on population dynamics of decomposer food webs was investigated in a semi-natural mixed deciduous forest in Denmark. Litterbags containing beech or ash leaves were placed in four plots. Plots were located within gaps and under closed...... at the end of the study period. At the first sampling, where bacterial activity prevailed, the relative abundance of the two dominant bacterial-feeders, Rhabditidae (fast growing) and Plectus spp. (slower growing), depended more on site than litter type. At the second sampling where fungal activity became...... in the decomposer food web, site effects were also detected and nematode functional groups responded more to site than to litter quality early on in the decomposition process....
Implications of heterogeneous fracture distribution on reservoir quality; an analogue from the Torridon Group sandstone, Moine Thrust Belt, NW Scotland

Science.gov (United States)

Watkins, Hannah; Healy, David; Bond, Clare E.; Butler, Robert W. H.

2018-03-01

Understanding fracture network variation is fundamental in characterising fractured reservoirs. Simple relationships between fractures, stress and strain are commonly assumed in fold-thrust structures, inferring relatively homogeneous fracture patterns. In reality fractures are more complex, commonly appearing as heterogeneous networks at outcrop. We use the Achnashellach Culmination (NW Scotland) as an outcrop analogue to a folded tight sandstone reservoir in a thrust belt. We present fracture data is collected from four fold-thrust structures to determine how fracture connectivity, orientation, permeability anisotropy and fill vary at different structural positions. We use a 3D model of the field area, constructed using field observations and bedding data, and geomechanically restored using Move software, to determine how factors such as fold curvature and strain influence fracture variation. Fracture patterns in the Torridon Group are consistent and predictable in high strain forelimbs, however in low strain backlimbs fracture patterns are inconsistent. Heterogeneities in fracture connectivity and orientation in low strain regions do not correspond to fluctuations in strain or fold curvature. We infer that where strain is low, other factors such as lithology have a greater control on fracture formation. Despite unpredictable fracture attributes in low strain regions, fractured reservoir quality would be highest here because fractures in high strain forelimbs are infilled with quartz. Heterogeneities in fracture attribute data on fold backlimbs mean that fractured reservoir quality and reservoir potential is difficult to predict.
Modelling voltage sag mitigation using dynamic voltage restorer and analyzing power quality issue

Science.gov (United States)

Ismail, Nor Laili; Hidzir, Hizrin Dayana Mohd; Thanakodi, Suresh; Nazar, Nazatul Shiema Moh; Ibrahim, Pungut; Ali, Che Ku Muhammad Sabri Che Ku

2018-02-01

Power quality problem which are arise due to a fault or a pulsed load can have caused an interruption of critical load. The modern power systems are becoming more sensitive to the quality of the power supplied by the utility company. Voltage sags and swells, flicker, interruptions, harmonic distortion and other distortion to the sinusoidal waveform are the examples of the power quality problems. The most affected due to these problems is industrial customers who use a lot of sensitive equipment. There has suffered a huge loss to these problems. Resulting of broken or damage equipment if voltage sag exceeds the sensitive threshold of the equipment. Thus, device such as Static Synchronous Compensator (STATCOM) and Dynamic Voltage Restorer (DVR) has been created to solve this problem among users. DVR is a custom power device that most effective and efficient. This paper intended to report the DVR operations during voltage sag compensation.
Green heterogeneous wireless networks

CERN Document Server

Ismail, Muhammad; Nee, Hans-Peter; Qaraqe, Khalid A; Serpedin, Erchin

2016-01-01

This book focuses on the emerging research topic "green (energy efficient) wireless networks" which has drawn huge attention recently from both academia and industry. This topic is highly motivated due to important environmental, financial, and quality-of-experience (QoE) considerations. Specifically, the high energy consumption of the wireless networks manifests in approximately 2% of all CO2 emissions worldwide. This book presents the authors’ visions and solutions for deployment of energy efficient (green) heterogeneous wireless communication networks. The book consists of three major parts. The first part provides an introduction to the "green networks" concept, the second part targets the green multi-homing resource allocation problem, and the third chapter presents a novel deployment of device-to-device (D2D) communications and its successful integration in Heterogeneous Networks (HetNets). The book is novel in that it specifically targets green networking in a heterogeneous wireless medium, which re...
Effects of Village Power Quality on Fuel Consumption and Operating Expenses

Energy Technology Data Exchange (ETDEWEB)

Richard Wies; Ron Johnson

2008-12-31

Alaska's rural village electric utilities are isolated from the Alaska railbelt electrical grid intertie and from each other. Different strategies have been developed for providing power to meet demand in each of these rural communities. Many of these communities rely on diesel electric generators (DEGs) for power. Some villages have also installed renewable power sources and automated generation systems for controlling the DEGs and other sources of power. For example, Lime Village has installed a diesel battery photovoltaic hybrid system, Kotzebue and Wales have wind-diesel hybrid systems, and McGrath has installed a highly automated system for controlling diesel generators. Poor power quality and diesel engine efficiency in village power systems increases the cost of meeting the load. Power quality problems may consist of poor power factor (PF) or waveform disturbances, while diesel engine efficiency depends primarily on loading, the fuel type, the engine temperature, and the use of waste heat for nearby buildings. These costs take the form of increased fuel use, increased generator maintenance, and decreased reliability. With the cost of bulk fuel in some villages approaching $1.32/liter ($5.00/gallon) a modest 5% decrease in fuel use can result in substantial savings with short payback periods depending on the village's load profile and the cost of corrective measures. This project over its five year history has investigated approaches to improving power quality and implementing fuel savings measures through the use of performance assessment software tools developed in MATLAB{reg_sign} Simulink{reg_sign} and the implementation of remote monitoring, automated generation control, and the addition of renewable energy sources in select villages. The results have shown how many of these communities would benefit from the use of automated generation control by implementing a simple economic dispatch scheme and the integration of renewable energy sources

Review of Comprehensive Evaluation Methods for Power Quality and Its Trend in New Generation Energy System

Science.gov (United States)

Liu, Ruihua; Wang, Rong; Liu, Qunying; Yang, Li; Xi, Chuan; Wang, Wei; Li, Lingzhou; Zhao, Zhoufang; Zhou, Ying

2018-02-01

With China’s new energy generation grid connected capacity being in the forefront of the world and the uncertainty of new energy sources, such as wind energy and solar energy, it is be of great significance to study scientific and comprehensive assessment of power quality. On the foundation of analysizing the current power quality index systematically and objectively, the new energy grid power quality analysis method and comprehensive evaluation method, this paper tentatively explored the trend of the new generation of energy system power quality comprehensive evaluation.
Qinshan Phase III (CANDU) nuclear power project quality assurance

International Nuclear Information System (INIS)

Wang Lingen; Du Jinxiang

2001-01-01

The completion and implementation of quality assurance system of Qinshan Phase III (CANDU) nuclear power project are presented. Some comments and understanding with consideration of the project characteristics are put forward
Integrating Photovoltaic Systems in Power System: Power Quality Impacts and Optimal Planning Challenges

Directory of Open Access Journals (Sweden)

Aida Fazliana Abdul Kadir

2014-01-01

Full Text Available This paper is an overview of some of the main issues in photovoltaic based distributed generation (PVDG. A discussion of the harmonic distortion produced by PVDG units is presented. The maximum permissible penetration level of PVDG in distribution system is also considered. The general procedures of optimal planning for PVDG placement and sizing are also explained in this paper. The result of this review shows that there are different challenges for integrating PVDG in the power systems. One of these challenges is integrated system reliability whereas the amount of power produced by renewable energy source is consistent. Thus, the high penetration of PVDG into grid can decrease the reliability of the power system network. On the other hand, power quality is considered one of the challenges of PVDG whereas the high penetration of PVDGs can lead to more harmonic propagation into the power system network. In addition to that, voltage fluctuation of the integrated PVDG and reverse power flow are two important challenges to this technology. Finally, protection of power system with integrated PVDG is one of the most critical challenges to this technology as the current protection schemes are designed for unidirectional not bidirectional power flow pattern.
Quality assurance program manual for nuclear power plants. Volume I. Policies

International Nuclear Information System (INIS)

1975-01-01

Policies and procedures are presented which comply with current NRC regulatory requirements and industry codes and standards in effect during the design, procurement, construction, testing, operation, refueling, maintenance, repair and modification activities associated with nuclear power plants. Specific NRC and industry documents that contain the requirements, including the issue dates in effect, are identified in each nuclear power plant's Safety Analysis Report. The requirements established by these documents form the basis for the Consumers Power Quality Assurance Program, which is implemented to control those structures, systems, components and operational safety actions listed in each nuclear power plant's Quality List (Q-List). As additional and revised requirements are issued by the NRC and professional organizations involved in nuclear activities, they will be reviewed for their impact on this manual, and changes will be made where considered necessary
Simple heterogeneity parametrization for sea surface temperature and chlorophyll

Science.gov (United States)

Skákala, Jozef; Smyth, Timothy J.

2016-06-01

Using satellite maps this paper offers a complex analysis of chlorophyll & SST heterogeneity in the shelf seas around the southwest of the UK. The heterogeneity scaling follows a simple power law and is consequently parametrized by two parameters. It is shown that in most cases these two parameters vary only relatively little with time. The paper offers a detailed comparison of field heterogeneity between different regions. How much heterogeneity is in each region preserved in the annual median data is also determined. The paper explicitly demonstrates how one can use these results to calculate representative measurement area for in situ networks.
Nonergodicity, fluctuations, and criticality in heterogeneous diffusion processes.

Science.gov (United States)

Cherstvy, A G; Metzler, R

2014-07-01

We study the stochastic behavior of heterogeneous diffusion processes with the power-law dependence D(x) ∼ |x|(α) of the generalized diffusion coefficient encompassing sub- and superdiffusive anomalous diffusion. Based on statistical measures such as the amplitude scatter of the time-averaged mean-squared displacement of individual realizations, the ergodicity breaking and non-Gaussianity parameters, as well as the probability density function P(x,t), we analyze the weakly nonergodic character of the heterogeneous diffusion process and, particularly, the degree of irreproducibility of individual realizations. As we show, the fluctuations between individual realizations increase with growing modulus |α| of the scaling exponent. The fluctuations appear to diverge when the critical value α = 2 is approached, while for even larger α the fluctuations decrease, again. At criticality, the power-law behavior of the mean-squared displacement changes to an exponentially fast growth, and the fluctuations of the time-averaged mean-squared displacement do not converge for increasing number of realizations. From a systematic comparison we observe some striking similarities of the heterogeneous diffusion process with the familiar subdiffusive continuous time random walk process with power-law waiting time distribution and diverging characteristic waiting time.
Comparison Of Power Quality Disturbances Classification Based On Neural Network

Directory of Open Access Journals (Sweden)

Nway Nway Kyaw Win

2015-07-01

Full Text Available Abstract Power quality disturbances PQDs result serious problems in the reliability safety and economy of power system network. In order to improve electric power quality events the detection and classification of PQDs must be made type of transient fault. Software analysis of wavelet transform with multiresolution analysis MRA algorithm and feed forward neural network probabilistic and multilayer feed forward neural network based methodology for automatic classification of eight types of PQ signals flicker harmonics sag swell impulse fluctuation notch and oscillatory will be presented. The wavelet family Db4 is chosen in this system to calculate the values of detailed energy distributions as input features for classification because it can perform well in detecting and localizing various types of PQ disturbances. This technique classifies the types of PQDs problem sevents.The classifiers classify and identify the disturbance type according to the energy distribution. The results show that the PNN can analyze different power disturbance types efficiently. Therefore it can be seen that PNN has better classification accuracy than MLFF.
Water quality monitoring device for nuclear power plant

International Nuclear Information System (INIS)

Kubo, Mitsushi.

1995-01-01

The device of the present invention measures quality of feedwater after heated in a regenerative heat exchanger device of a coolant cleanup system in a BWR type reactor, to detect ions generated from organic materials decomposed at high temperature and specify the position where impurities are formed. Namely, in a power plant having a reactor coolant cleanup pipeline connected to a feedwater pipeline, a water quality measuring portion is disposed to the feedwater system at the downstream of the junction to the feedwater system pipeline. A water quality sample is taken to measure the water quality in a state where the feedwater heated by a feedwater heater and flowing to the reactor, and the cleanup coolants heated by the regenerative heat exchanger are mixed. Thus, the impurities formed at the down stream of the feedwater system pipeline, as well as the water quality including impurities decomposed in a high temperature state can be measured. (I.S.)
Best control strategy for unified power quality conditioner (UPQC) based on simulation

Energy Technology Data Exchange (ETDEWEB)

Shayanfar, H.A. [Iran Univ. of Science and Technology, Tehran (Iran, Islamic Republic of). Dept. of Electrical Engineering; Tabatabaei, N.M. [Azarbaijan Univ. of Tarbiat Moallem, Tabriz (Iran, Islamic Republic of). Dept. of Electrical Engineering; Mokhtarpour, A. [Islamic Azad Univ., Tabriz (Iran, Islamic Republic of). Dept. of Electrical Engineering

2007-07-01

Electronic devices used in both industry and residences need high-quality energy to work properly. Unified Power Quality Conditioners (UPQC) solve any power quality problems faced by these devices. Three new control strategies for UPQCs were presented and their operation was investigated and compared using the MATLAB Simulink simulation software package. A UPQC consists of a Shunt-Active Filter and a Series Active Filter with a common direct current link to compensate for any source currents and delivered voltage to the load. As such, it isolates the utility from current quality problems associated with load. It also isolates the load from the voltage quality problems of the utility. In the first control strategy, the Parallel Active Filter (PAF) and Series Active Filter (SAF) are based on the Fourier transform theory. In the second control strategy, the Parallel Active Filter is based on the power quality theory and the Series Active Filter is based on the Fourier transform theory. In the third control strategy, the Parallel Active Filter is based on Fourier transform theory and the Series Active Filter is based on positive sequence detection. Operating the PAF using these methods compensates for reactive power and current harmonics, while operating the SAF compensates for imbalances, voltage harmonics and positive and zero sequences of utility voltages. MATLAB simulation software was used to explain the compensation resolution and speed of the 3 new control strategies. According to simulation test results, it was concluded that the best compensation speed and resolution can be obtained using the third control strategy. 7 refs., 2 tabs., 24 figs.
Water quality maintaining device of power plant

International Nuclear Information System (INIS)

Kobayashi, Minoru; Inami, Ichiro.

1994-01-01

The device of the present invention reduces the amount of leaching materials of ion exchange resins from a water processing system of a BWR tyep plant, improves the water quality of reactor water to maintain the water at high purity. That is, steams used for power generation are condensated in a condensate system. A condensate filter and a condensate desalter for cleaning the condensates are disposed. A resin storage hopper is disposed for supplying the ion exchange resins to the water processing system. A device for supplying a nitrogen gas or an inert gas is disposed in the hopper. With such a constitution, the ion exchange resins in the water processing system are maintained in a nitrogen gas or inert gas atmosphere or at a low dissolved oxygen level in an operation stage in the power plant. Accordingly, degradation of the ion exchange resins in the water processing system is suppressed and the amount of the leaching material from the resins is reduced. As a result, the amount of the resins leached into the reactor is reduced, so that the reactor water quality can be maintained at high purity. (I.S.)
Overall quality assurance program requirements for nuclear power plants

International Nuclear Information System (INIS)

1992-09-01

This standard contains the requirements for the owner's overall quality assurance program for a nuclear power plant. This program encompasses all phases of a nuclear power plant life cycle, including site evaluation, design, procurement, manufacturing, construction and installation, commissioning, operation, and decommissioning. It covers the activities associated with specifying, directing, and administering the work to be done during these phases, and the evaluation and integrated of the activities and programs of participants
Effects of low heterogeneity in fast critical assemblies

International Nuclear Information System (INIS)

Belov, S.P.; Dulin, V.A.; Zhukov, A.V.; Kuzin, E.N.; Mozhaev, V.K.; Sitnikov, V.I.; Tsibulya, A.M.; Shapar', A.V.; Zayfert, E.; Kuntsman, B.; Khayntsel'man, B.

1989-01-01

The problem of the low heterogeneity of fast critical assemblies, which are used to simulate fast reactors that are under design, has begun to assume increasing importance as the errors in nuclear data and group constants decrease and the capabilities of design codes improve. The design of the fuel channels of the fast critical assemblies of a BFS differs from that of the fuel subassemblies of a power reactor. The principal difference is that critical assemblies have a more heterogeneous structure than a reactor core does. As a result, the effects of this heterogeneity turn out to be appreciable for a number of functionals. Of particular interest was the measurement of the main neutronic characteristics of a fast reactor in its actual design and in the mockup produced by using BFS facilities. The authors measured and calculated the most important functionals (the ratios of the average cross sections of the main absorbing and fissioning elements, etc.) for both a homogeneous medium (fuel assemblies) and a heterogeneous medium (slugs, tubes) of practically identical composition. The objective of this work was to compare the discrepancy between experiment and calculations for the central functionals in the homogeneous and heterogeneous cases after corrections. This is a check of the accuracy of the simulation of homogeneous cores in fast power reactors by using the tools of the BFS fast critical assembly
Z-Source Inverter Based Power Quality Compensator with Enhanced Ride-Through Capability

DEFF Research Database (Denmark)

Gajanayake, C.J.; Vilathgamuwa, D.M.; Loh, P.C.

2007-01-01

Distributed generation has been gaining acceptance over the years and it has the potential to provide reliable power to sensitive loads. However, distributed networks are prone to unbalanced faults conditions. This makes single inverter DG systems unsuitable as UPS systems. This paper proposes...... a Zsource inverter based power quality compensator and a control structure that supplies high quality voltage to the connected sensitive load in the presence of other non linear loads. The proposed topology consists of combination of shunt and series inverters connected to a common Z-source impedance...... network. The shunt inverter is controlled to maintain a quality voltage waveform at the load bus. Whereas the series inverter enhances the ride-through capability during grid faults, protects the shunt inverter by limiting the current and also controls the power delivered to the grid. The performance...
A control strategy for multi-functional converter to improve grid power quality

DEFF Research Database (Denmark)

Li, Fei; Wang, Xiongfei; Chen, Zhe

2011-01-01

The extensive use of converter-interfacing distributed energy resources (DER), combined with a large amount of nonlinear and unbalanced loads connected to the distribution power system, has led to power quality problem. This paper proposes a control strategy for a three-phase four-leg multi-funct......) for multi-functional converter is described. Simulation and hardware in the loop real time test results carried on a three-phase four-wire distributed generation system illustrate the effectiveness of the proposed control strategy.......The extensive use of converter-interfacing distributed energy resources (DER), combined with a large amount of nonlinear and unbalanced loads connected to the distribution power system, has led to power quality problem. This paper proposes a control strategy for a three-phase four-leg multi......-functional converter which can compensate reactive power, harmonic currents, unbalance, and neutral current simultaneously under distorted voltage conditions, besides the active power exchange. The capacity of the converter is taken into account. The proposed control strategy based on synchronous reference frame (SRF...
HIGH TEMPERATURE, HIGH POWER HETEROGENEOUS NUCLEAR REACTOR

Science.gov (United States)

Hammond, R.P.; Wykoff, W.R.; Busey, H.M.

1960-06-14

A heterogeneous nuclear reactor is designed comprising a stationary housing and a rotatable annular core being supported for rotation about a vertical axis in the housing, the core containing a plurality of radial fuel- element supporting channels, the cylindrical empty space along the axis of the core providing a central plenum for the disposal of spent fuel elements, the core cross section outer periphery being vertically gradated in radius one end from the other to provide a coolant duct between the core and the housing, and means for inserting fresh fuel elements in the supporting channels under pressure and while the reactor is in operation.
Improving quality and the assurance of quality in the design and construction of nuclear power plants: a report to Congress

International Nuclear Information System (INIS)

Altman, W.; Ankrum, T.; Brach, W.

1984-05-01

A study was conducted of existing and alternative programs for improving quality and the assurance of quality in the design and construction of commercial nuclear power plants. A primary focus of the study was to determine the underlying causes of major quality-related problems in the construction of some nuclear power plants and the untimely detection and correction of these problems. The study concluded that the root cause for major quality-related problems was the failure or inability of some utility managements to effectively implement a management system that ensured adequate control over all aspects of the project. These management shortcoming arose in part from inexperience on the part of some project teams in the construction of nuclear power plants. NRC's past licensing and inspection practices did not adequately screen construction permit applicants for overall capability to manage or provide effective management oversight over the construction project. The study recommends a number of improvements in industry and NRC programs. For industry, the study recommends self-imposed rising standards of excellence, treatment of quality assurance as a management tool, not a substitute for management, improved trend analysis and identification of root causes of quality problems, and a program of comprehensive third party audits of present and future construction projects. To improve NRC programs, the study recommends a heavier emphasis on team inspections and resident inspectors, an enhanced review of new applicant's capabilities to construct commercial nuclear power plants, more attention to management issues, improved diagnostic and trending capabilities, improved quality and quality assurance for operating reactors, and development of guidance to facilitate the prioritization of quality assurance measures commensurate with the importance of plant structures, systems, and components to the achievement of safety
Assembly-level analysis of heterogeneous Th–Pu PWR fuel

International Nuclear Information System (INIS)

Zainuddin, Nurjuanis Zara; Parks, Geoffrey T.; Shwageraus, Eugene

2017-01-01

Highlights: • We directly compare homogeneous and heterogeneous Th–Pu fuel. • Examine whether there is an increase in Pu incineration in the latter. • Homogeneous fuel was able to achieve much higher Pu incineration. • In the heterogeneous case, U-233 breeding is faster (larger power fraction), thus decreasing incineration of Pu. - Abstract: This study compares homogeneous and heterogeneous thorium–plutonium (Th–Pu) fuel assemblies (with high Pu content – 20 wt%), and examines whether there is an increase in Pu incineration in the latter. A seed-blanket configuration based on the Radkowsky thorium reactor concept is used for the heterogeneous assembly. This separates the thorium blanket from the uranium seed, or in this case a plutonium seed. The seed supplies neutrons to the subcritical thorium blanket which encourages the in situ breeding and burning of "2"3"3U, allowing the fuel to stay critical for longer, extending burnup of the fuel. While past work on Th–Pu seed-blanket units shows superior Pu incineration compared to conventional U–Pu mixed oxide fuel, there is no literature to date that directly compares the performance of homogeneous and heterogeneous Th–Pu assembly configurations. Use of exactly the same fuel loading for both configurations allows the effects of spatial separation to be fully understood. It was found that the homogeneous fuel with and without burnable poisons was able to achieve much higher Pu incinerations than the heterogeneous fuel configurations, while still attaining a reasonably high discharge burnup. This is because in the heterogeneous cases, "2"3"3U breeding is faster, thereby contributing to a much larger fraction of total power produced by the assembly. In contrast, "2"3"3U build-up is slower in the homogeneous case and therefore Pu burning is greater. This "2"3"3U begins to contribute a significant fraction of power produced only towards the end of life, thus extending criticality, allowing more Pu to
ANALYSIS OF FACTORS AFFECTING POST-POWER SYNDROME AND QUALITY OF LIFE IN THE ELDERLY

Directory of Open Access Journals (Sweden)

Retno Indarwati

2017-10-01

Full Text Available Background: Quality of life is the individual's perception of their place in life in the context of the cultural system and values in which they live, along with their goals, expectations, and worries. Retirement is an adaptable period that results in a change of role, changes in social interactions, and limited financial resources. Aim: This study aims to analyze the factors that affect post power syndrome and quality of life of the elderly. Methods: The design of this research was a correlation study with a cross-sectional approach. The population consisted of 44 retired elderly individuals. Purposive sampling was applied to the determined sample size. The independent variables were physiological stressors, psychological stressors and aging attitudes. The dependent variables were post-power syndrome and the quality of life of elderly people. The data were analyzed using Structural Equation Modeling- Partial Least Square (SEM-PLS with a significance t statistic ≥ 1.96. Results: The findings showed all of the significant indicators measured to the variable factor. Physical stressor factors affect post-power syndrome with a t value of 2,366, and psychological stress factors affect post-power syndrome with a t value of 3,326. Aging behavior factors affects post-power syndrome with a t statistic of 5.296 and the post-power syndrome effect on the quality of life of the elderly has a t value of 7,689. Conclusion: There were significant effects in relation to physiological stressor factors, psychological stress factors, and aging attitudes towards post-power syndrome. There was an influence of post-power syndrome on the quality of elderly life.
The impact of turbulent renewable energy production on power grid stability and quality

Science.gov (United States)

Schmietendorf, Katrin; Peinke, Joachim; Kamps, Oliver

2017-11-01

Feed-in fluctuations induced by renewables are one of the key challenges to the stability and quality of electrical power grids. In particular short-term fluctuations disturb the system on a time scale, on which load balancing does not operate yet and the system is intrinsically governed by self-organized synchronization. Wind and solar power are known to be strongly non-Gaussian with intermittent increment statistics in these time scales. We investigate the impact of short-term wind fluctuations on the basis of a Kuramoto-like power grid model considering stability in terms of desynchronization and frequency and voltage quality aspects. We present a procedure to generate realistic feed-in fluctuations with temporal correlations, Kolmogorov power spectrum and intermittent increments. By comparison to correlated Gaussian noise of the same spectrum and Gaussian white noise, we found out that while the correlations are essential to capture the likelihood of severe outages, the intermittent nature of wind power has significant consequences on power quality: intermittency is directly transferred into frequency and voltage fluctuations yielding a novel type of fluctuations, which is beyond engineering status of knowledge.
Quality assurance for CMS Tracker LV and HV Power Supplies

CERN Document Server

Costa, Marco; Sertoli, M; Trapani, P; Periale, L; Isabella, L; Landi, C; Lucchesi, A

2007-01-01

This work describes the quality assurance measurements that have been carried out on about 2000 Power Supply Units produced in CAEN technology for the CMS Silicon Tracker Detector. The automate procedure and the characteristics of the dedicated Test Fixture developed for this activity are described in details. Magnetic field tolerance and radiation hardness of Tracker power supply units is also discussed at length.

Comparative Evaluation of two Models of UPQC for Suitable Interface to Enhance Power Quality

OpenAIRE

Basu, Malabika; Das, S. P.; Dubey, Gopal

2007-01-01

Majority of the dispersed generations from renewable energy sources are connected to the grid through power electronic interface, which introduce additional harmonics in the distribution systems. Research is being carried out to integrate active filtering with specific interface such that a common power quality (PQ) platform could be achieved. For generalized solution, a unified power quality conditioner (UPQC) could be the most comprehensive PQ protecting device for sensitive non-linear load...
Improving operator quality at Genkai Nuclear Power Plant

International Nuclear Information System (INIS)

Kuwano, Takeshi.

1989-01-01

Improvement in operator quality, or improvement in an operator's skill and professional knowledge, is of prime importance because of its great influence on safe and steady plant operation. This paper describes the education and training of reactor operators at the Genkai pressurized water reactor nuclear power plant with respect to the following topics: organization of Genkai power plant; education and training program management; training at the Nuclear Training Center; training and education on-site including emergency procedures training, normal operating procedures training, informational study of emergency conditions in existing plants, and all-around training of operators; qualifying tests for supervisors; and operator motivation
Power quality considerations for nuclear spectroscopy applications: Grounding

Science.gov (United States)

García-Hernández, J. M.; Ramírez-Jiménez, F. J.; Mondragón-Contreras, L.; López-Callejas, R.; Torres-Bribiesca, M. A.; Peña-Eguiluz, R.

2013-11-01

Traditionally the electrical installations are designed for supplying power and to assure the personnel safety. In nuclear analysis laboratories, additional issues about grounding also must be considered for proper operation of high resolution nuclear spectroscopy systems. This paper shows the traditional ways of grounding nuclear spectroscopy systems and through different scenarios, it shows the effects on the more sensitive parameter of these systems: the energy resolution, it also proposes the constant monitoring of a power quality parameter as a way to preserve or to improve the resolution of the systems, avoiding the influence of excessive extrinsic noise.
Heterogeneity in earnings quality between different classes of companies after IFRS adoption: evidence from Brazil

Directory of Open Access Journals (Sweden)

Roberto Black

Full Text Available ABSTRACT This paper aims to investigate the existence of heterogeneity in earnings quality between different classes of companies after the adoption of the International Financial Reporting Standards (IFRS. IFRS adoption is generally associated with an increase in the quality of financial statements. However, companies within the same country are likely to have different economic incentives regarding the disclosure of information. Thus, treating companies equally, without considering the related economic incentives, could contaminate earnings quality investigations. The case of Brazil is analyzed, which is a country classified as code-law, in which tax laws determined accounting practice and in which IFRS adoption is mandatory. First, Brazilian companies listed on the São Paulo Stock, Commodities, and Futures Exchange (BM&FBOVESPA were separated into two classes: companies issuing American Depositary Receipts (ADRs before IFRS adoption and companies that did not issue ADRs until the adoption of IFRS. Then, this second class of companies was grouped, using cluster analysis, into two different subclasses according to economic incentives. Based on the groups identified, the quality of accounting earnings is tested for each class of the companies before and after IFRS adoption. This paper uses timely recognition of economic events, value relevance of net income, and earnings management as proxies for the quality of accounting earnings. The results indicate that a particular class of companies began showing conditional conservatism, value relevance of net income, and lower earnings management after IFRS adoption. On the other hand, these results were not found for the two other classes of companies.
Quality assurance in the construction phase of the Guangdong Daya Bay Nuclear Power Plant

International Nuclear Information System (INIS)

Chen Heling; Zou Xiaoshun

1994-11-01

The quality assurance system of Guangdong Daya Bay Nuclear Power Plant during construction phase is briefly introduced. It includes the quality assurance organization and multiple quality control system of the owner (GNPJVC) and contractors. The status of the programmes implementation has been also described through presenting of some important quality assurance activities such as quality surveillance, QA audit and nonconformance control. In addition, the effectiveness of GNPP Construction QA Program has been analyzed and evaluated and both positive and negative experience have been summarized which could be used for reference by the nuclear power constructors. (6 figs.)
Quality assurance in the construction phase of the Guangdong Daya Bay Nuclear Power Plant

Energy Technology Data Exchange (ETDEWEB)

Heling, Chen; Xiaoshun, Zou [Guangdong Nuclear Power Joint Venture Company (China)

1994-11-01

The quality assurance system of Guangdong Daya Bay Nuclear Power Plant during construction phase is briefly introduced. It includes the quality assurance organization and multiple quality control system of the owner (GNPJVC) and contractors. The status of the programmes implementation has been also described through presenting of some important quality assurance activities such as quality surveillance, QA audit and nonconformance control. In addition, the effectiveness of GNPP Construction QA Program has been analyzed and evaluated and both positive and negative experience have been summarized which could be used for reference by the nuclear power constructors. (6 figs.).
Quality assurance auditing for nuclear power plants

International Nuclear Information System (INIS)

1980-01-01

This Safety Guide provides requirements and recommendations for establishing and implementing a system of internal and external audits during the design, manufacture, construction, commissioning and operation of nuclear power plants. It provides for the planning, performance, reporting and follow-up of the quality assurance audit activity. It defines in general terms the responsibilities of the auditing and audited organizations. The Guide also covers auditing in the context of supplier evaluation; it does not include inspection for the sole purpose of process control or product acceptance. Like the Code, the present Guide was prepared as part of the IAEA's programme, referred to as the NUSS programme, for establishing Codes of Practice and Safety Guides relating to land-based stationary thermal neutron power plants
Bruce Power's nuclear pressure boundary quality assurance program requirements, implementation and transition

International Nuclear Information System (INIS)

Krane, J.C.

2009-01-01

The development of a full scope nuclear pressure boundary quality assurance program in Canada requires extensive knowledge of the structure and detailed requirements of codes and standards published by the Canadian Standards Association (CSA) and American Society of Mechanical Engineers (ASME). Incorporation into company governance documents and implementation of these requirements while managing the transition to more recent revisions of these codes and standards represents a significant challenge for Bruce Power, Canada's largest independent nuclear operator. This paper explores the key developments and innovative changes that are used to ensure successful regulatory compliance and effective implementation of the Bruce Power Pressure Boundary Quality Assurance Program. Challenges and mitigating strategies to sustain this large compliance based program at Bruce Power's 8 unit nuclear power plant site will also be detailed. (author)
Enhanced machine learning scheme for energy efficient resource allocation in 5G heterogeneous cloud radio access networks

KAUST Repository

Alqerm, Ismail

2018-02-15

Heterogeneous cloud radio access networks (H-CRAN) is a new trend of 5G that aims to leverage the heterogeneous and cloud radio access networks advantages. Low power remote radio heads (RRHs) are exploited to provide high data rates for users with high quality of service requirements (QoS), while high power macro base stations (BSs) are deployed for coverage maintenance and low QoS users support. However, the inter-tier interference between the macro BS and RRHs and energy efficiency are critical challenges that accompany resource allocation in H-CRAN. Therefore, we propose a centralized resource allocation scheme using online learning, which guarantees interference mitigation and maximizes energy efficiency while maintaining QoS requirements for all users. To foster the performance of such scheme with a model-free learning, we consider users\\' priority in resource blocks (RBs) allocation and compact state representation based learning methodology to enhance the learning process. Simulation results confirm that the proposed resource allocation solution can mitigate interference, increase energy and spectral efficiencies significantly, and maintain users\\' QoS requirements.
Power monitors: A framework for system-level power estimation using heterogeneous power models

NARCIS (Netherlands)

Bansal, N.; Lahiri, K.; Raghunathan, A.; Chakradhar, S.T.

2005-01-01

Paper analysis early in the design cycle is critical for the design of low-power systems. With the move to system-level specifications and design methodologies, there has been significant research interest in system-level power estimation. However, as demonstrated in this paper, the addition of
Digital image analysis of testicular and prostatic ultrasonographic echogencity and heterogeneity in dogs and the relation to semen quality

OpenAIRE

Moxon, Rachel; Bright, Lucy; Pritchard, Beth; Bowen, I. Mark; Souza, Mírley Barbosa de; Silva, Lúcia Daniel Machado da; England, Gary C.W.

2015-01-01

A semi-automated ultrasonographic method was developed to measure echogenicity and heterogeneity of the testes and prostate gland and relationships of these measures with semen quality were assessed in 43 fertile dogs. The relationship between animal age and body weight upon the volume of the testes, epididymal tail volume and prostate volume were also established.\\ud \\ud Mean testicular echogenicity was negatively correlated with the percentage of morphologically normal live spermatozoa (mor...
A Review of Distributed Control Techniques for Power Quality Improvement in Micro-grids

Science.gov (United States)

Zeeshan, Hafiz Muhammad Ali; Nisar, Fatima; Hassan, Ahmad

2017-05-01

Micro-grid is typically visualized as a small scale local power supply network dependent on distributed energy resources (DERs) that can operate simultaneously with grid as well as in standalone manner. The distributed generator of a micro-grid system is usually a converter-inverter type topology acting as a non-linear load, and injecting harmonics into the distribution feeder. Hence, the negative effects on power quality by the usage of distributed generation sources and components are clearly witnessed. In this paper, a review of distributed control approaches for power quality improvement is presented which encompasses harmonic compensation, loss mitigation and optimum power sharing in multi-source-load distributed power network. The decentralized subsystems for harmonic compensation and active-reactive power sharing accuracy have been analysed in detail. Results have been validated to be consistent with IEEE standards.
Quality assurance system for conventional island erection of Daya Day Nuclear Power Plant

Energy Technology Data Exchange (ETDEWEB)

Zhongliang, Shi; Suozhi, Wu; Xiangke, Meng [Shandong Electric Power Construction Corp. Nuclear Power Construction Company (China)

1994-12-01

The process concerning the establishment, operation and perfection of Quality Assurance System (QA system) experienced by Shandong Electric Power Construction Corporation, Nuclear Power Construction Company (SEPC-NPCC) during the implementation of Conventional Island Erection (CIE) in Daya Bay Nuclear Power Plant is introduced. Apart from systematic description of the principle for working out QA programme and QA procedures and their main contents, it is also detailed, on a combination of theory with practice basis, how the major departments constituting the QA system such as Quality Assurance, Quality Control, Construction and Administration and Business Departments have made fruitful efforts as per the individual responsibility for ensuring the work quality and having in mind the principles specified by QA programme and the requirements of QA procedures. As a result of the reasonable combination of the 3 crucial points and the 4 essential elements of the QA system, high quality of CI erection has been realized. The importance of quality supervision and management review by the owner and upper levels of authorities for ensuring effective operation of QA system is affirmed. The practical experience of CIE project proves that the strict inspection/surveillance on all activities and service affecting quality carried out by QA Department independent of project management and QC Dept, independent of construction management are of quite importance for ensuring the project quality. (4 tabs.).
Quality assurance system for conventional island erection of Daya Day Nuclear Power Plant

International Nuclear Information System (INIS)

Shi Zhongliang; Wu Suozhi; Meng Xiangke

1994-12-01

The process concerning the establishment, operation and perfection of Quality Assurance System (QA system) experienced by Shandong Electric Power Construction Corporation, Nuclear Power Construction Company (SEPC-NPCC) during the implementation of Conventional Island Erection (CIE) in Daya Bay Nuclear Power Plant is introduced. Apart from systematic description of the principle for working out QA programme and QA procedures and their main contents, it is also detailed, on a combination of theory with practice basis, how the major departments constituting the QA system such as Quality Assurance, Quality Control, Construction and Administration and Business Departments have made fruitful efforts as per the individual responsibility for ensuring the work quality and having in mind the principles specified by QA programme and the requirements of QA procedures. As a result of the reasonable combination of the 3 crucial points and the 4 essential elements of the QA system, high quality of CI erection has been realized. The importance of quality supervision and management review by the owner and upper levels of authorities for ensuring effective operation of QA system is affirmed. The practical experience of CIE project proves that the strict inspection/surveillance on all activities and service affecting quality carried out by QA Department independent of project management and QC Dept, independent of construction management are of quite importance for ensuring the project quality. (4 tabs.)
Approximation Algorithm for a Heterogeneous Vehicle Routing Problem

Directory of Open Access Journals (Sweden)

Jungyun Bae

2015-08-01

Full Text Available This article addresses a fundamental path planning problem which aims to route a collection of heterogeneous vehicles such that each target location is visited by some vehicle and the sum of the travel costs of the vehicles is minimal. Vehicles are heterogeneous as the cost of traveling between any two locations depends on the type of the vehicle. Algorithms are developed for this path planning problem with bounds on the quality of the solutions produced by the algorithms. Computational results show that high quality solutions can be obtained for the path planning problem involving four vehicles and 40 targets using the proposed approach.
Cognitive Heterogeneous Reconfigurable Optical Networks (CHRON): Enabling Technologies and Techniques

DEFF Research Database (Denmark)

Tafur Monroy, Idelfonso; Zibar, Darko; Guerrero Gonzalez, Neil

2011-01-01

We present the approach of cognition applied to heterogeneous optical networks developed in the framework of the EU project CHRON: Cognitive Heterogeneous Reconfigurable Optical Network. We introduce and discuss in particular the technologies and techniques that will enable a cognitive optical...... network to observe, act, learn and optimizes its performance, taking into account its high degree of heterogeneity with respect to quality of service, transmission and switching techniques....
Artificial enzyme-powered microfish for water-quality testing.

Science.gov (United States)

Orozco, Jahir; García-Gradilla, Victor; D'Agostino, Mattia; Gao, Wei; Cortés, Allan; Wang, Joseph

2013-01-22

We present a novel micromotor-based strategy for water-quality testing based on changes in the propulsion behavior of artificial biocatalytic microswimmers in the presence of aquatic pollutants. The new micromotor toxicity testing concept mimics live-fish water testing and relies on the toxin-induced inhibition of the enzyme catalase, responsible for the biocatalytic bubble propulsion of tubular microengines. The locomotion and survival of the artificial microfish are thus impaired by exposure to a broad range of contaminants, that lead to distinct time-dependent irreversible losses in the catalase activity, and hence of the propulsion behavior. Such use of enzyme-powered biocompatible polymeric (PEDOT)/Au-catalase tubular microengine offers highly sensitive direct optical visualization of changes in the swimming behavior in the presence of common contaminants and hence to a direct real-time assessment of the water quality. Quantitative data on the adverse effects of the various toxins upon the swimming behavior of the enzyme-powered artificial swimmer are obtained by estimating common ecotoxicological parameters, including the EC(50) (exposure concentration causing 50% attenuation of the microfish locomotion) and the swimmer survival time (lifetime expectancy). Such novel use of artificial microfish addresses major standardization and reproducibility problems as well as ethical concerns associated with live-fish toxicity assays and hence offers an attractive alternative to the common use of aquatic organisms for water-quality testing.
Quality and Safety Assurance - Priority Task at Nuclear Power Projects Implementation

International Nuclear Information System (INIS)

Nenkova, B.; Manchev, B.; Tomov, E.

2010-01-01

Quality and safety assurance at implementation of nuclear power engineering projects is important and difficult task for realization. Many problems arise during this process, when many companies from different countries participate, with various kinds of activities and services provided. The scope of activities necessary for quality and safety assurance is therefore quite expanded and diverse. In order to increase the safety and reliability of Kozloduy NPP Plc (KNPP) Units 5 and 6, as well as to bring the units in conformity with the newest international requirements for quality and safety in the field of nuclear energy, a program for their modernization on the basis of different technical studies and assessments was implemented. The Units 5 and 6 Modernization Program of Kozloduy Nuclear Power Plant was composed of 212 modifications aimed to improve the safety, operability, and reliability of the Units. The Program was realized by stages during yearly planned outages since year 2002 to 2007, without additional outages. A major Program Objective was to extend the Units Life Time in at least 15 Years, under a continuous, safe, and reliable operation. The Modernization Program of Units 5 and 6 of the Bulgarian Nuclear Power Plant in Kozloduy was the first and for the time being the only one in the world, program in the field of nuclear power engineering, by which the full scope of recommendations for improvement of the Kozloduy NPP units was applied. The main goal of the National Electric Company, which is the Employer for the construction of new nuclear facility in Bulgaria, is after completion of all activities regarding construction of Belene NPP the plant to meet or exceed the requirements of the respective national and international quality and safety codes and standards, as well as the IAEA guidelines, as they are established. The objective of this report is to describe different aspects of the quality assurance according to the requirements of quality and
Views on quality assurance at Finnish and Swedish nuclear power plants and at Halden Reactor

International Nuclear Information System (INIS)

Hammar, L.; Lidh, B.; Wahlstroem, B.; Reiman, T.

2001-06-01

The paper reports on a study within the Nordic Nuclear Safety Research, NKS on quality systems at nuclear installations in Finland, Norway and Sweden. In the study a total of 74 people at the NPPs in Barsebaeck, Forsmark, Loviisa, Olkiluoto, Oskarshamn and Ringhals, and at the research reactor in Halden were interviewed in the period 30 August to 13 December 2000 concerning their views in regard of quality and quality systems. The study was concluded with a seminar held in the Ringhals nuclear power plant in Januar 2001. The study covered a number of aspects in regard of quality management, including the quality concept, quality systems, topical quality issues and approaches, rules and procedures, competency and training, the process approach to quality management, the promotion of quality consciousness and future prospects. The study reflects the significant progress made in the management of quality in nuclear power in the Nordic countries since the early phase in the seventies. The most distinctive characteristic of today's approach to quality is seen in that responsibility for the quality is assumed directly in conjunction with the working processes. It could be noted that the work patterns at the nuclear installations have been largely modified during the recent years as a result of persistent endeavours to continuously improve the quality of operation. Challenges were seen in currently reduced revenues due to descending electricity prices and the likely prospect of further increased regulatory safety requirements. The report is aimed for those working with quality issues at the nuclear power plants as well as for those interested in quality management in general or in the safety aspects of nuclear power in particular. (au)
Treatment of liquid wastes from decontamination of nuclear power plants by heterogeneous photocatalysis

International Nuclear Information System (INIS)

Morgada, Maria Eugenia

2002-01-01

In nuclear power plants high radiation fields are produced, not only in the core but also in the auxiliary systems, due, mainly, to the activation of corrosion products by means of a mechanism known as 'Activity Transport'.With the purpose of reducing at minimum values the intensity of radiation fields and of avoiding the operative problems generated by the deposition of oxides in tanks and pipelines, it is necessary to remove the oxide films, carriers of activity, from the components in auxiliary systems in nuclear power plants and this is usually carried on by chemical cleaning.This process, known as decontamination, is done employing mixtures of oligocarboxilic acids such as NTA, EDTA, oxalic acid, citric acid, etc., at concentration nearly 1% and pH 3-4.The resulting liquid wastes of this process cannot be discharged directly to the environment but must be properly treated.Conventional treatments such as thermolysis, chemical oxidation and others show some problems and, in addition, some of these substances are resistant to degradation.Previous work done in the Unidad de Actividad Quimica del Centro Atomico Constituyentes (UAQ-CAC) indicated that Heterogeneous Photocatalysis, belonging to the Advanced Oxidation Technologies (AOTs), could be a useful procedure for the treatment of liquid decontamination wastes. This method consists on the irradiation of an aqueous suspension of a semiconductor, generally TiO 2 , containing the substrate to be degraded, employing wavelengths shorter than the semiconductor's 'band-gap'.In this way, oxidant and reducing molecules are generated.The advantages compared to other AOTs are its low cost, the ability to work at room temperature and pressure, it uses only oxygen as oxidizing agent and can be operated in 'batch' and continuum.In the present work we employed a recycling system, with a black-light tubular UV lamp (366nm) installed inside as the source of illumination, to study the degradation of oxalic and citric acid by

Power quality affects teacher wellbeing and student behavior in three Minnesota Schools

International Nuclear Information System (INIS)

Havas, Magda; Olstad, Angela

2008-01-01

Background: Poor power quality (dirty electricity) is ubiquitous especially in schools with fluorescent lights and computers. Previous studies have shown a relationship between power quality and student behavior/teacher health. Objectives: The purpose of this study is to determine the ability of power line filters to reduce dirty electricity in a school environment and to document changes in health and behavior among teachers and students. Method: We installed Graham Stetzer filters and dummy filters and measured power quality in three Minnesota Schools. Teachers completed a daily questionnaire regarding their health and the behavior of their students for an 8-week period. Teachers were unaware of which filters were installed at any one time (single blind study). Results: Dirty electricity was reduced by more than 90% in the three schools and during this period teacher health improved as did student behavior in the middle/elementary schools. Headaches, general weakness, dry eyes/mouth, facial flushing, asthma, skin irritations, overall mood including depression and anxiety improved significantly among staff. Of the 44 teachers who participated 64% were better, 30% were worse, and 6% did not change. Behavior of high school students did not improve but elementary/middle school students were more active in class; more responsive, more focused; had fewer health complaints; and had a better overall learning experience. Conclusions: Dirty electricity in schools may be adversely affecting wellbeing of teachers and behavior of their students, especially younger students in middle and elementary school. Power line filters improve power quality and may also protect those who are sensitive to this energy. Work on electric and magnetic field metrics with and without Stetzer filters urgently needs to be carried out to determine just what characteristics of the dirty electricity may be interacting with the people
Application-specific mesh-based heterogeneous FPGA architectures

CERN Document Server

Parvez, Husain

2011-01-01

This volume presents a new exploration environment for mesh-based, heterogeneous FPGA architectures. Readers will find a description of state-of-the-art techniques for reducing area requirements, which both increase performance and enable power reduction.
A new scheme for maximizing the lifetime of heterogeneous wireless sensor networks

OpenAIRE

Aldaihani, Reem; AboElFotoh, Hosam

2016-01-01

Heterogeneous wireless sensor network consists of wireless sensor nodes with different abilities, such as different computing power and different initial energy. We present in this paper a new scheme for maximizing heterogeneous WSN lifetime. The proposed scheme employs two types of sensor nodes that are named (consistent with IEEE 802.15.4 standard) Full Function Device (FFD) and Reduced Function Device (RFD). The FFDs are the expensive sensor nodes with high power and computational capabili...
Analysis and experimental evaluation of shunt active power filter for power quality improvement based on predictive direct power control.

Science.gov (United States)

Aissa, Oualid; Moulahoum, Samir; Colak, Ilhami; Babes, Badreddine; Kabache, Nadir

2017-10-12

This paper discusses the use of the concept of classical and predictive direct power control for shunt active power filter function. These strategies are used to improve the active power filter performance by compensation of the reactive power and the elimination of the harmonic currents drawn by non-linear loads. A theoretical analysis followed by a simulation using MATLAB/Simulink software for the studied techniques has been established. Moreover, two test benches have been carried out using the dSPACE card 1104 for the classic and predictive DPC control to evaluate the studied methods in real time. Obtained results are presented and compared in this paper to confirm the superiority of the predictive technique. To overcome the pollution problems caused by the consumption of fossil fuels, renewable energies are the alternatives recommended to ensure green energy. In the same context, the tested predictive filter can easily be supplied by a renewable energy source that will give its impact to enhance the power quality.
Quality assurance during site construction of nuclear power plants

International Nuclear Information System (INIS)

1981-01-01

This Safety Guide provides requirements and recommendations related to the establishment and implementation of a quality assurance programme for the site construction activities at nuclear power plants. These include activities such as fabricating, erecting, installing, handling, storing, cleaning, flushing, inspecting, testing, modifying, repairing, and maintaining
Power quality event classification: an overview and key issues ...

African Journals Online (AJOL)

... used for PQ events' classifications. Various artificial intelligent techniques which are used in PQ event classification are also discussed. Major Key issues and challenges in classifying PQ events are critically examined and outlined. Keywords: Power quality, PQ event classifiers, artificial intelligence techniques, PQ noise, ...
METHODOLOGY OF DETERMINATION OF QUALITY INDEX OF MAINTENANCE SERVICE SYSTEM OF POWER EQUIPMENT OF TRACTION SUBSTATIONS

Directory of Open Access Journals (Sweden)

O.O. Matusevych

2016-03-01

Full Text Available Purpose. The purpose of this paper is development of methodology for definition of a quality system of maintenance and repair (M and P power equipment of traction substations (TS of electrified railways operating under conditions of uncertainty based on expert information. Methodology. The basic tenets of the theory of fuzzy sets and marks, linguistic and interval estimates of experts were applied to solve this problem. Results. Analysis of the existing diversity of approaches to development of modern methods of improvement of M and P allows us to conclude that the improvement in the quality of the system is achieved by solving individual problems increase the operational reliability of power equipment of traction substations in the following main interrelated areas. There are technical, economic and organizational. The basis of the quality evaluation system is initial data and expertise developed version of the document formalized quality evaluation of electrical equipment of traction substations by experts. The choice of determining the level of Quality service system based on the marks, linguistic and interval estimates of experts, which are reflected in quantitative and / or qualitative form was done. The possible options for expert data presentation and their corresponding quantitative methods of calculating the integral index of quality improvement system maintenance and P of traction substations were described. The methodology and the method of assessing the quality of system maintenance and P of TS allows quickly respond to changing operating conditions of power equipment of traction substations, and to determine the most effective strategies for maintenance of electrical and P TS under conditions of uncertainty functioning distance electricity. Originality. The method of a systematic approach to improve the quality of the system maintenance and P of power equipment of traction substation under conditions of uncertainty based on expert
MATLAB Simulation of UPQC for Power Quality Mitigation Using an Ant Colony Based Fuzzy Control Technique.

Science.gov (United States)

Kumarasabapathy, N; Manoharan, P S

2015-01-01

This paper proposes a fuzzy logic based new control scheme for the Unified Power Quality Conditioner (UPQC) for minimizing the voltage sag and total harmonic distortion in the distribution system consequently to improve the power quality. UPQC is a recent power electronic module which guarantees better power quality mitigation as it has both series-active and shunt-active power filters (APFs). The fuzzy logic controller has recently attracted a great deal of attention and possesses conceptually the quality of the simplicity by tackling complex systems with vagueness and ambiguity. In this research, the fuzzy logic controller is utilized for the generation of reference signal controlling the UPQC. To enable this, a systematic approach for creating the fuzzy membership functions is carried out by using an ant colony optimization technique for optimal fuzzy logic control. An exhaustive simulation study using the MATLAB/Simulink is carried out to investigate and demonstrate the performance of the proposed fuzzy logic controller and the simulation results are compared with the PI controller in terms of its performance in improving the power quality by minimizing the voltage sag and total harmonic distortion.
MATLAB Simulation of UPQC for Power Quality Mitigation Using an Ant Colony Based Fuzzy Control Technique

Directory of Open Access Journals (Sweden)

N. Kumarasabapathy

2015-01-01

Full Text Available This paper proposes a fuzzy logic based new control scheme for the Unified Power Quality Conditioner (UPQC for minimizing the voltage sag and total harmonic distortion in the distribution system consequently to improve the power quality. UPQC is a recent power electronic module which guarantees better power quality mitigation as it has both series-active and shunt-active power filters (APFs. The fuzzy logic controller has recently attracted a great deal of attention and possesses conceptually the quality of the simplicity by tackling complex systems with vagueness and ambiguity. In this research, the fuzzy logic controller is utilized for the generation of reference signal controlling the UPQC. To enable this, a systematic approach for creating the fuzzy membership functions is carried out by using an ant colony optimization technique for optimal fuzzy logic control. An exhaustive simulation study using the MATLAB/Simulink is carried out to investigate and demonstrate the performance of the proposed fuzzy logic controller and the simulation results are compared with the PI controller in terms of its performance in improving the power quality by minimizing the voltage sag and total harmonic distortion.
Quality assurance and non-destructive testing for nuclear power plants

International Nuclear Information System (INIS)

Manlucu, F.A.

1991-01-01

This article discussed the quality assurance requirements which have been extensively applied in plant design, fabrication, construction and operation and has played a major role in the excellent safety record of nuclear power plants. The application of non-destructive testing techniques, plays a very important role during the in-service inspection (ISI) in order to prevent dangerous accident and to assure continuous safe operation of nuclear power plants. (IMA). 12 refs
Power Quality Improvement Utilizing Photovoltaic Generation Connected to a Weak Grid

Energy Technology Data Exchange (ETDEWEB)

Muljadi, Eduard [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Tumbelaka, Hanny H. [Petra Christian University; Gao, Wenzhong [UNiversity of Denver

2017-11-07

Microgrid research and development in the past decades have been one of the most popular topics. Similarly, the photovoltaic generation has been surging among renewable generation in the past few years, thanks to the availability, affordability, technology maturity of the PV panels and the PV inverter in the general market. Unfortunately, quite often, the PV installations are connected to weak grids and may have been considered as the culprit of poor power quality affecting other loads in particular sensitive loads connected to the same point of common coupling (PCC). This paper is intended to demystify the renewable generation, and turns the negative perception into positive revelation of the superiority of PV generation to the power quality improvement in a microgrid system. The main objective of this work is to develop a control method for the PV inverter so that the power quality at the PCC will be improved under various disturbances. The method is to control the reactive current based on utilizing the grid current to counteract the negative impact of the disturbances. The proposed control method is verified in PSIM platform. Promising results have been obtained.
Power quality challenges in future distribution networks; Aspekte der Strom- und Spannungsqualitaet in kuenftigen Verteilungsnetzen

Energy Technology Data Exchange (ETDEWEB)

Klatt, Matthias; Meyer, Jan; Schegner, Peter [TU Dresden (Germany)

2011-07-01

Power quality in distribution grids is determined by consumer topology, generation topology, network topology and environmental influences (i.e. weather). New developments like decentralized power generation or e-mobility lead to significant changes in the grids as well as the equipment connected thereto. This paper discusses possible impacts of new technologies on power quality and is intended to attract attention of stakeholders to these issues. (orig.)
Overload cascading failure on complex networks with heterogeneous load redistribution

Science.gov (United States)

Hou, Yueyi; Xing, Xiaoyun; Li, Menghui; Zeng, An; Wang, Yougui

2017-09-01

Many real systems including the Internet, power-grid and financial networks experience rare but large overload cascading failures triggered by small initial shocks. Many models on complex networks have been developed to investigate this phenomenon. Most of these models are based on the load redistribution process and assume that the load on a failed node shifts to nearby nodes in the networks either evenly or according to the load distribution rule before the cascade. Inspired by the fact that real power-grid tends to place the excess load on the nodes with high remaining capacities, we study a heterogeneous load redistribution mechanism in a simplified sandpile model in this paper. We find that weak heterogeneity in load redistribution can effectively mitigate the cascade while strong heterogeneity in load redistribution may even enlarge the size of the final failure. With a parameter θ to control the degree of the redistribution heterogeneity, we identify a rather robust optimal θ∗ = 1. Finally, we find that θ∗ tends to shift to a larger value if the initial sand distribution is homogeneous.
Heterogeneously Integrated Microwave Signal Generators with Narrow Linewidth Lasers

Science.gov (United States)

2017-03-20

have shown that heterogeneous integration not only allows for a reduced cost due to economy of scale, but also allows for same or even better...advantage of introducing SOAs for microwave generator is the control and boosting of optical power before the detector providing higher RF powers. A
Best Practices: Power Quality and Integrated Testing at JSC

Science.gov (United States)

Davis, Lydia

2018-01-01

This presentation discusses Best Practices for Power Quality and Integrated Testing at JSC in regards to electrical systems. These high-level charts include mostly generic information; however, a specific issue is discussed involving flight hardware that could have been discovered prior to flight with an integrated test.
Design and Analysis of Grid Connected Photovoltaic Fed Unified Power Quality Conditioner

Science.gov (United States)

Dash, Santanu Kumar; Ray, Pravat Kumar

2016-06-01

This paper proposes the integration scheme and operation of the Unified Power Quality conditioner (UPQC) with Photovoltaic source as distributed generations for power quality improvement. Thus, it provides a novel PV-grid integration configuration and prevents any adverse situation related to current or voltage in power system. Voltage related issues are maintained by the series part of UPQC and the current related issues are handles by shunt part of the UPQC. The various operation modes of PV-UPQC schemes are broadly classified according to the direction of power flow, (i) Interconnected mode, (ii) Islanding mode. PV-UPQC has advantage over the conventional UPQC scheme as it has developed the capability to compensate the voltage interruption problems Control algorithms for shunt and series part of the UPQC is implemented. Development of the proposed configuration has been designed in the laboratory with control algorithm implemented in dSPACE and results are discussed.
Overview of Power Quality and Integrated Testing at JSC

Science.gov (United States)

Davies, Francis

2018-01-01

This presentation describes the basic philosophy behind integrated testing and partially integrated testing. It lists some well known errors in space systems that were or could have been caught during integrated testing. Two examples of integrated testing at the Johnson Space Center (JSC) are mentioned, and then an overview of two test facilities that do power testing (partially integrated testing) at JSC are presented, with information on the capabilities of each. Finally a list of three projects that has problems caught during power quality or Electromagnetic Interference (EMI) testing is presented.
Multifunctional voltage source inverter for renewable energy integration and power quality conditioning.

Science.gov (United States)

Dai, NingYi; Lam, Chi-Seng; Zhang, WenChen

2014-01-01

In order to utilize the energy from the renewable energy sources, power conversion system is necessary, in which the voltage source inverter (VSI) is usually the last stage for injecting power to the grid. It is an economical solution to add the function of power quality conditioning to the grid-connected VSI in the low-voltage distribution system. Two multifunctional VSIs are studied in this paper, that is, inductive-coupling VSI and capacitive-coupling VSI, which are named after the fundamental frequency impedance of their coupling branch. The operation voltages of the two VSIs are compared when they are used for renewable energy integration and power quality conditioning simultaneously. The operation voltage of the capacitive-coupling VSI can be set much lower than that of the inductive-coupling VSI when reactive power is for compensating inductive loads. Since a large portion of the loads in the distribution system are inductive, the capacitive-coupling VSI is further studied. The design and control method of the multifunctional capacitive-coupling VSI are proposed in this paper. Simulation and experimental results are provided to show its validity.
Electric Power quality Analysis in research reactor: Impacts on nuclear safety assessment and electrical distribution reliability

International Nuclear Information System (INIS)

Touati, Said; Chennai, Salim; Souli, Aissa

2015-01-01

The increased requirements on supervision, control, and performance in modern power systems make power quality monitoring a common practise for utilities. Large databases are created and automatic processing of the data is required for fast and effective use of the available information. Aim of the work presented in this paper is the development of tools for analysis of monitoring power quality data and in particular measurements of voltage and currents in various level of electrical power distribution. The study is extended to evaluate the reliability of the electrical system in nuclear plant. Power Quality is a measure of how well a system supports reliable operation of its loads. A power disturbance or event can involve voltage, current, or frequency. Power disturbances can originate in consumer power systems, consumer loads, or the utility. The effect of power quality problems is the loss power supply leading to severe damage to equipments. So, we try to track and improve system reliability. The assessment can be focused on the study of impact of short circuits on the system, harmonics distortion, power factor improvement and effects of transient disturbances on the Electrical System during motor starting and power system fault conditions. We focus also on the review of the Electrical System design against the Nuclear Directorate Safety Assessment principles, including those extended during the last Fukushima nuclear accident. The simplified configuration of the required system can be extended from this simple scheme. To achieve these studies, we have used a demo ETAP power station software for several simulations. (authors)
Electric Power quality Analysis in research reactor: Impacts on nuclear safety assessment and electrical distribution reliability

Energy Technology Data Exchange (ETDEWEB)

Touati, Said; Chennai, Salim; Souli, Aissa [Nuclear Research Centre of Birine, Ain Oussera, Djelfa Province (Algeria)

2015-07-01

The increased requirements on supervision, control, and performance in modern power systems make power quality monitoring a common practise for utilities. Large databases are created and automatic processing of the data is required for fast and effective use of the available information. Aim of the work presented in this paper is the development of tools for analysis of monitoring power quality data and in particular measurements of voltage and currents in various level of electrical power distribution. The study is extended to evaluate the reliability of the electrical system in nuclear plant. Power Quality is a measure of how well a system supports reliable operation of its loads. A power disturbance or event can involve voltage, current, or frequency. Power disturbances can originate in consumer power systems, consumer loads, or the utility. The effect of power quality problems is the loss power supply leading to severe damage to equipments. So, we try to track and improve system reliability. The assessment can be focused on the study of impact of short circuits on the system, harmonics distortion, power factor improvement and effects of transient disturbances on the Electrical System during motor starting and power system fault conditions. We focus also on the review of the Electrical System design against the Nuclear Directorate Safety Assessment principles, including those extended during the last Fukushima nuclear accident. The simplified configuration of the required system can be extended from this simple scheme. To achieve these studies, we have used a demo ETAP power station software for several simulations. (authors)

Manual on quality assurance for the survey, evaluation and confirmation of nuclear power plant sites

International Nuclear Information System (INIS)

1987-04-01

The present Manual on Quality Assurance for the Survey, Evaluation and Confirmation of Nuclear Power Plant Sites contains supporting material and illustrates examples for implementing the requirements contained in the Code of Practice on Quality Assurance for Safety in Nuclear Power Plants to the activities of survey, evaluation and confirmation of nuclear power plant sites. At the same time the Code of Practice for Safety in Nuclear Power Plant Siting, and Safety Guides in the siting series contain requirements and recommendations to implement a quality assurance programme in selected activities of the siting process. This manual is intended to provide guidance and illustrate examples on this implementation. During preparation and reviews of this Manual it was found out that the methodology of implementation of the quality assurance programme in siting activities is still under development. For these reasons it was considered appropriate to publish this Manual as a temporary publication for trial use
Optimizing structure of complex technical system by heterogeneous vector criterion in interval form

Science.gov (United States)

Lysenko, A. V.; Kochegarov, I. I.; Yurkov, N. K.; Grishko, A. K.

2018-05-01

The article examines the methods of development and multi-criteria choice of the preferred structural variant of the complex technical system at the early stages of its life cycle in the absence of sufficient knowledge of parameters and variables for optimizing this structure. The suggested methods takes into consideration the various fuzzy input data connected with the heterogeneous quality criteria of the designed system and the parameters set by their variation range. The suggested approach is based on the complex use of methods of interval analysis, fuzzy sets theory, and the decision-making theory. As a result, the method for normalizing heterogeneous quality criteria has been developed on the basis of establishing preference relations in the interval form. The method of building preferential relations in the interval form on the basis of the vector of heterogeneous quality criteria suggest the use of membership functions instead of the coefficients considering the criteria value. The former show the degree of proximity of the realization of the designed system to the efficient or Pareto optimal variants. The study analyzes the example of choosing the optimal variant for the complex system using heterogeneous quality criteria.
Real-Time Supervisory Control for Power Quality Improvement of Multi-Area Microgrids

DEFF Research Database (Denmark)

Hashempour, Mohammad M.; Lee, Tzung-Lin; Savaghebi, Mehdi

2018-01-01

In this paper, the power quality (PQ) improvement of Multi-Area Microgrid (MAMGs) is addressed. To this aim, mitigation of voltage harmonics and unbalance is considered by using Distributed Generators (DGs) and Active Power Filters (APFs) in a proper way. As a novel approach, the main goal...
Studies of spatial decoupling in heterogeneous LMFBR critical assemblies

International Nuclear Information System (INIS)

Brumbach, S.B.; Goin, R.W.; Carpenter, S.G.

1984-01-01

Recent measurements at the Zero Power Plutonium Reactor have studied the spatial decoupling in large, heterogeneous assemblies. These assemblies exhibited a significantly greater degree of decoupling than previous homogeneous assemblies of similar size. The flux distributions in these heterogeneous assemblies were very sensitive reactivity perturbations, and perturbed flux distributions were achieved relatively slowly. Decoupling was investigated using rod-drop, boron-oscillator and noise-coherence techniques which emphasized different times following the perturbations. Reactivity changes could be measured by analyzing the power history from a single detector using inverse kinetics methods with the assumption of an instantaneous efficiency change for the detector. For assemblies more decoupled than ZPPR-13, the instantaneous efficiency change assumption begins to be invalid
High power quality for customers; De l'electricite de qualite chez les industriels

Energy Technology Data Exchange (ETDEWEB)

Calani, B. [Electricite de France (EDF), 93 - Saint-Denis (France); Tanneau, G. [Electricite de France (EDF), 92 - Clamart (France)

2000-01-01

The electrical power quality is a strong criterion for many manufacturers. The improvement of the electrical network and devices has allowed to reach a good power quality level all over the French territory which satisfies the majority of most customer's expectations. However, in some cases, only local desensitization can ne efficient enough to meet the customer's requirement. Emergent equipment based on power electronic devices are evaluated at the Research and Development Division. The aim is to propose the best service offer to our customers on both technical and economical aspects. (authors)
Measuring educational heterogeneity and labor quality

DEFF Research Database (Denmark)

Fosgerau, Mogens; Hougaard Jensen, Svend E.; Sørensen, Anders

2002-01-01

This paper investigates the magnitude of the mismeasurement that occurs when only a few education categories are used in the construction of a constant quality index for labor input. By employing a very comprehensive data set it is found that the error resulting from the omission of information...... on education is relatively small. The empirical results are thus supportive of the current state of practice of constructing indices of constant quality labor input....
Roles of the operator and the safety services in nuclear power plant quality assurance

International Nuclear Information System (INIS)

Widmer, M.; Perrot, J.

1985-01-01

With regard to the operation of nuclear power plants, Electricite de France formally recognized in 1973 that it was necessary for safety reasons and economically acceptable to adopt organizational principles of quality assurance that would be applicable both to its own activities and to those of its suppliers. Generally speaking, the form and spirit of the quality assurance programme chosen is based largely on the Code of Practice No. 50-C-QA. In particular, the programme focuses on the flexible character of quality assurance requirements and stresses that in the final analysis product quality depends above all on those to whom the project has been assigned, because it is they who are responsible for meeting the quality objectives set. Ten years of experience with the suppliers of Electricite de France has shown that these suppliers, after some initial difficulty, have been able to adapt the application of quality assurance so as to achieve satisfactory quality as regards both safety and availability. In the case of the French standard nuclear power plants, quality assurance is particularly important thanks to the traceability which it affords and to the allowance for corrective measures which it demands. The safety services normally take action related to quality assurance in three ways: through regulation, the analysis of measures to assure plant safety, and plant supervision. As regards regulation, an order has just been published relating to design, construction and operational quality in base-load nuclear power plants. The requirements laid down in this document incorporate the recommendations of the IAEA Code on quality assurance. (author)
Issues of improving quality of training personnel for nuclear power facilities

International Nuclear Information System (INIS)

Jacko, J.

1987-01-01

The basic stages are characterized of the development of a standard system of personnel training for the start-up, operation and maintenance of nuclear power facilities. The experience is analyzed gained by the Branch Training Centre of the Nuclear Power Plant Research Institute. Suggestions are submitted for improving the quality of personnel training based on Czechoslovak and foreign experiences. (author). 3 refs
Transcription elongation. Heterogeneous tracking of RNA polymerase and its biological implications.

Science.gov (United States)

Imashimizu, Masahiko; Shimamoto, Nobuo; Oshima, Taku; Kashlev, Mikhail

2014-01-01

Regulation of transcription elongation via pausing of RNA polymerase has multiple physiological roles. The pausing mechanism depends on the sequence heterogeneity of the DNA being transcribed, as well as on certain interactions of polymerase with specific DNA sequences. In order to describe the mechanism of regulation, we introduce the concept of heterogeneity into the previously proposed alternative models of elongation, power stroke and Brownian ratchet. We also discuss molecular origins and physiological significances of the heterogeneity.
Manual on quality assurance for computer software related to the safety of nuclear power plants

International Nuclear Information System (INIS)

1988-01-01

The objective of the Manual is to provide guidance in the assurance of quality of specification, design, maintenance and use of computer software related to items and activities important to safety (hereinafter referred to as safety related) in nuclear power plants. This guidance is consistent with, and supplements, the requirements and recommendations of Quality Assurance for Safety in Nuclear Power Plants: A Code of Practice, 50-C-QA, and related Safety Guides on quality assurance for nuclear power plants. Annex A identifies the IAEA documents referenced in the Manual. The Manual is intended to be of use to all those who, in any way, are involved with software for safety related applications for nuclear power plants, including auditors who may be called upon to audit management systems and product software. Figs
A game theoretical approach for QoS provisioning in heterogeneous networks

Directory of Open Access Journals (Sweden)

A.S.M. Zadid Shifat

2015-09-01

Full Text Available With the proliferation of mobile phone users, interference management is a big concern in this neoteric years. To cope with this problem along with ensuring better Quality of Service (QoS, femtocell plays an imperious preamble in heterogeneous networks (HetNets for some of its noteworthy characteristics. In this paper, we propose a game theoretic algorithm along with dynamic channel allocation and hybrid access mechanism with self-organizing power control scheme. With a view to resolving prioritized access issue, the concept of primary and secondary users is applied. Existence of pure strategy Nash equilibrium (NE has been investigated and comes to a perfection that our proposed scheme can be adopted both increasing capacity and increasing revenue of operators considering optimal price for consumers.
Water quality control method and device for nuclear power plant and nuclear power plant

International Nuclear Information System (INIS)

Nagase, Makoto; Asakura, Yamato; Uetake, Naoto; Sawa, Toshio; Uchida, Shunsuke; Takeda, Renzo; Osumi, Katsumi.

1993-01-01

In a BWR type nuclear power plant, water quality of coolants is controlled so as to lower deposition rate of Co ions in reactor water on a fuel cladding tube. The water quality control method includes (1) decreasing an iron concentration in feedwater to less than 0.1ppb, (2) adjusting coolants weakly acidic and (3) controlling dissolved oxygen concentration in reactor water to 20ppb. This can decrease 60 Co ion concentration even if 60 Co ion concentration is increased by the change of environment for the operation in future, such as an operation with hydrogen injection and extention of fuel burnup degree. (T.M.)
Muscle Power Is an Independent Determinant of Pain and Quality of Life in Knee Osteoarthritis.

Science.gov (United States)

Reid, Kieran F; Price, Lori Lyn; Harvey, William F; Driban, Jeffrey B; Hau, Cynthia; Fielding, Roger A; Wang, Chenchen

2015-12-01

This study examined the relationships between leg muscle strength, power, and perceived disease severity in subjects with knee osteoarthritis (OA) in order to determine whether dynamic leg extensor muscle power would be associated with pain and quality of life in knee OA. Baseline data on 190 subjects with knee OA (mean ± SD age 60.2 ± 10.4 years, body mass index 32.7 ± 7.2 kg/m(2) ) were obtained from a randomized controlled trial. Knee pain was measured using the Western Ontario and McMaster Universities Osteoarthritis Index, and health-related quality of life was assessed using the Short Form 36 (SF-36). One-repetition maximum (1RM) strength was assessed using the bilateral leg press, and peak muscle power was measured during 5 maximum voluntary velocity repetitions at 40% and 70% of 1RM. In univariate analysis, greater muscle power was significantly associated with pain (r = -0.17, P power was a significant independent predictor of pain (P ≤ 0.05) and PCS scores (P ≤ 0.04). However, muscle strength was not an independent determinant of pain or quality of life (P ≥ 0.06). Muscle power is an independent determinant of pain and quality of life in knee OA. Compared to strength, muscle power may be a more clinically important measure of muscle function within this population. New trials to systematically examine the impact of muscle power training interventions on disease severity in knee OA are particularly warranted. © 2015, American College of Rheumatology.
Quality surveillance at Duke Power operating nuclear stations

International Nuclear Information System (INIS)

Bradley, W.H.

1985-01-01

The Duke Power quality assurance (QA) program originally had three levels of QA audits that reported results to different levels of management and in different time frames. It soon became obvious that although problems were being identified, considerable confusion was being created by reporting them to different levels. Additionally, it was recognized that all audits were dealing in history: events that had already occurred and therefore could not be averted. What was needed was a problem identification system focused on current activities. The Duke quality surveillance program was created by dropping the first level of audits and replacing it with an on-the-scene review system to identify current problems. The quality surveillance program is a success and will be even more so after surveillance personnel acquire additional technical expertise. To that end, a training program has been initiated that will stop just short of operator licensing in the operations area and will also include other areas such as health physics and chemistry
Heterogeneous characters modeling of instant message services users' online behavior.

Science.gov (United States)

Cui, Hongyan; Li, Ruibing; Fang, Yajun; Horn, Berthold; Welsch, Roy E

2018-01-01

Research on temporal characteristics of human dynamics has attracted much attentions for its contribution to various areas such as communication, medical treatment, finance, etc. Existing studies show that the time intervals between two consecutive events present different non-Poisson characteristics, such as power-law, Pareto, bimodal distribution of power-law, exponential distribution, piecewise power-law, et al. With the occurrences of new services, new types of distributions may arise. In this paper, we study the distributions of the time intervals between two consecutive visits to QQ and WeChat service, the top two popular instant messaging services in China, and present a new finding that when the value of statistical unit T is set to 0.001s, the inter-event time distribution follows a piecewise distribution of exponential and power-law, indicating the heterogeneous character of IM services users' online behavior in different time scales. We infer that the heterogeneous character is related to the communication mechanism of IM and the habits of users. Then we develop a combination model of exponential model and interest model to characterize the heterogeneity. Furthermore, we find that the exponent of the inter-event time distribution of the same service is different in two cities, which is correlated with the popularity of the services. Our research is useful for the application of information diffusion, prediction of economic development of cities, and so on.
Heterogeneous Computing in Economics: A Simplified Approach

DEFF Research Database (Denmark)

Dziubinski, Matt P.; Grassi, Stefano

This paper shows the potential of heterogeneous computing in solving dynamic equilibrium models in economics. We illustrate the power and simplicity of the C++ Accelerated Massive Parallelism recently introduced by Microsoft. Starting from the same exercise as Aldrich et al. (2011) we document a ...
A Single-Phase Voltage-Controlled Grid-Connected Photovoltaic System With Power Quality Conditioner Functionality

DEFF Research Database (Denmark)

Kerekes, Tamas; Liserre, Marco; Mastromauro, R. A.

2009-01-01

Future ancillary services provided by photovoltaic (PV) systems could facilitate their penetration in power systems. Also low power PV systems can be designed to improve the power quality. This paper presents a single-phase photovoltaic system that provides grid voltage support and compensation o...
A Robust Synchronization to Enhance the Power Quality of Renewable Energy Systems

DEFF Research Database (Denmark)

Hadjidemetriou, Lenos; Kyriakides, Elias; Blaabjerg, Frede

2015-01-01

The increasing penetration of renewable energy sources (RESs) in the power grid requires high-quality power injection under various grid conditions. The synchronization method, usually a phase-locked loop (PLL) algorithm, is directly affecting the response of the grid-side converter of the RES....... This paper proposes a new PLL algorithm that uses an advanced decoupling network implemented in the stationary reference frame with limited requirements for processing time to enable a fast and accurate synchronization even under harmonic distorted voltage and low-voltage grid faults. The robust response...... of the proposed PLL is validated, and the effect of the proposed synchronization on the performance of the grid-connected renewable energy system is investigated. This investigation proves that the robust, accurate, and dynamic response of the new PLL can enhance the quality of the injected power from the RES...
Quality Assurance in the Vandellos 1 Nuclear Power Plant Dismantling and Decommissioning Project

International Nuclear Information System (INIS)

Soto Lanuza, A.

2000-01-01

General description of the Quality Assurance System established and implemented for the efficient development of the current activities specified in the Dismantling and Decommissioning Plan for Vandellos I Nuclear Power Plant. Aspects related to the Quality organization, scope and applicability on the established Quality Assurance Manual, availability of requirements and recommendations on quality as well as actions to be taken for the correct verification on the quality and practical application of the Manual should be described. (Author)
Quality assurance grading of conventional equipment at nuclear power station

International Nuclear Information System (INIS)

Li Ping; Li Shichang

2006-01-01

Equipment QA grading with the systematic and standardized approach will benefit the concerned organizations by effective allocating of limited resources to guarantee the quality of essential equipment. This paper presents a new quality assurance grading system for the convention systems/equipment of nuclear power station, which is operative and at the same time could help the owner to allot resource reasonably through the analysis of the purpose of grading and the experience and lessons of LINGAO Phase I project. (authors)

Quality assurance during operation of nuclear power plants

International Nuclear Information System (INIS)

Modemann, G.

1990-01-01

The demands of the licensing authorities and the Nuclear Safety Regulations (KTA Rules) on the one hand and the utility's requirements on the other hand have led to the quality assurance system for the operation of nuclear power plants. One part of the system is the organizational structure for the distribution of all tasks and responsibilities to qualified staff members; all checks are carried out by experts who are independent of the executing staff if necessary. The other part of the system comprises the procedural structures for operation, maintenance, inspection, repair and modifications as well as for procurement and preparation of materials and spare parts. The application and efficiency of the quality assurance system is supervised and periodically checked by an independent department. (orig.) [de
Inefficiency persistence and heterogeneity in Colombian electricity utilities

International Nuclear Information System (INIS)

Galán, Jorge E.; Pollitt, Michael G.

2014-01-01

The electricity reform in Colombia has exhibited gains in terms of reliability but its effects on firm efficiency and service quality have not been clear. Previous studies evaluating the performance of distribution companies after the reform have not found evidence of improvements, although large differences in efficiency have been found among firms. This suggests high inefficiency persistence and heterogeneity in the Colombian distribution sector. In this paper, we propose an extension of dynamic stochastic frontier models that accounts for unobserved heterogeneity in the inefficiency persistence and in the technology. The model incorporates total expenses, service quality and energy losses in an efficiency analysis of Colombian distributors over fifteen years after the reform. We identify the presence of high inefficiency persistence in the sector, and important differences between firms. In particular, rural companies and firms with small customers present low persistence and evidence the largest gains in efficiency during the period. However, increases in efficiency are only manifested during thelast five years when the main improvements in service quality and energy losses are presented. Overall, inefficiency persistence, customer density and consumption density are found to be important criteria to be considered for regulatory purposes. - Highlights: • We evaluate efficiency of Colombian electricity distributors after the reform. • We use a stochastic frontier model with dynamic effects and heterogeneity. • We find high inefficiency persistence but important differences among firms. • High persistent and low efficient firms should draw the attention of the regulator. • Recent regulation in quality has increased not only efficiency but also tariffs
Construction quality assurance for nuclear power plants

Energy Technology Data Exchange (ETDEWEB)

NONE

1983-10-01

This Standard contains the requirements for the quality assurance program applicable to the construction phase of a nuclear power plant. This Standard covers all activities carried out for and by the owner from the receipt of components or materials on the site to their incorporation in systems or structures as required by drawings or other formal engineering information. It also covers the provision of required support activities and equipment and applies at all stages on the site as far as the testing of components or systems before they are submitted for commissioning. 2 figs.
Construction quality assurance for nuclear power plants

International Nuclear Information System (INIS)

1983-10-01

This Standard contains the requirements for the quality assurance program applicable to the construction phase of a nuclear power plant. This Standard covers all activities carried out for and by the owner from the receipt of components or materials on the site to their incorporation in systems or structures as required by drawings or other formal engineering information. It also covers the provision of required support activities and equipment and applies at all stages on the site as far as the testing of components or systems before they are submitted for commissioning. 2 figs
Heterogeneous Multicore Parallel Programming for Graphics Processing Units

Directory of Open Access Journals (Sweden)

Francois Bodin

2009-01-01

Full Text Available Hybrid parallel multicore architectures based on graphics processing units (GPUs can provide tremendous computing power. Current NVIDIA and AMD Graphics Product Group hardware display a peak performance of hundreds of gigaflops. However, exploiting GPUs from existing applications is a difficult task that requires non-portable rewriting of the code. In this paper, we present HMPP, a Heterogeneous Multicore Parallel Programming workbench with compilers, developed by CAPS entreprise, that allows the integration of heterogeneous hardware accelerators in a unintrusive manner while preserving the legacy code.
Use of Smart Sensors in the Measurement of Power Quality

Directory of Open Access Journals (Sweden)

A. Moreno-Muñoz

2008-03-01

Full Text Available Today’s businesses depend heavily on electrical services for lighting, general power, computer hardware and communications hardware. With the generalized use of sophisticated electronic devices, industries are shifting toward almost entirely electronic IT systems. PQ events are of increasing concern for the economy because today’s equipment, particularly computers and automated manufacturing devices, is highly sensitive to such imperfections. Traditionally the control and supervision of a plant distribution network has mainly been focused on the protection of the network. Relatively little attention has been focused on the quality of the electrical energy. Metering technologies and communications systems have advanced to enable the development of web-based sensors. Power Quality is one area where these smart sensors can be very valuable. This paper investigates the challenges and possibilities in the development of distributed PQ measurement systems. This paper describes the challenges and lessons learned from this work.
Comparative evaluation of two models of UPQC for suitable interface to enhance power quality

Energy Technology Data Exchange (ETDEWEB)

Basu, Malabika [Department of Electrical Engineering, Dublin Institute of Technology, Kevin Street, Dublin 8 (Ireland); Das, Shyama P.; Dubey, Gopal K. [Department of Electrical Engineering, Indian Institute of Technology, Kanpur (India)

2007-05-15

Majority of the dispersed generations from renewable energy sources are connected to the grid through power electronic interface, which introduce additional harmonics in the distribution systems. Research is being carried out to integrate active filtering with specific interface such that a common power quality (PQ) platform could be achieved. For generalized solution, a unified power quality conditioner (UPQC) could be the most comprehensive PQ protecting device for sensitive non-linear loads, which require quality input supply. Also, load current harmonic isolation needs to be ensured for maintaining the quality of the supply current. The present paper describes two control scheme models for UPQC, for enhancing PQ of sensitive non-linear loads. Based on two different kinds of voltage compensation strategy, two control schemes have been designed, which are termed as UPQC-Q and UPQC-P. A comparative loading analysis has developed useful insight in finding the typical application of the two different control schemes. The effectiveness of the two control schemes is verified through extensive simulation using the software SABER. As the power circuit configuration of UPQC remains same for both the model, with modification of control scheme only, the utility of UPQC can be optimized depending upon the application requirement. (author)
GENDER CONFORMITY, PERCEPTIONS OF SHARED POWER, AND MARITAL QUALITY IN SAME- AND DIFFERENT-SEX MARRIAGES.

Science.gov (United States)

Pollitt, Amanda M; Robinson, Brandon A; Umberson, Debra

2018-01-01

Research on gender inequality within different-sex marriages shows that women do more unpaid labor than men, and that the perception of inequality influences perceptions of marital quality. Yet research on same-sex couples suggests the importance of considering how gender is relational. Past studies show that same-sex partners share unpaid labor more equally and perceive greater equity than do different-sex partners, and that lesbian, gay, and bisexual people are less gender conforming than heterosexuals. However, studies have not considered how gender conformity might shape inequalities and marital quality within same- and different-sex unions. In this study, we analyze dyadic data from both spouses in same- and different-sex marriages to explore how sex of spouse and gender conformity influence perceptions of shared power within the relationship, which, in turn, influences marital quality. Results show that greater gender conformity is related to stronger perceptions of shared power in different-sex and male same-sex couples but not in female same-sex couples. Perceptions of shared power are positively associated with marital quality in all union types. Our findings suggest that maintaining hegemonic masculinity and power inequalities may be salient to marriages with men. In female same-sex couples, gender and its relation to power inequalities may carry less meaning.
Why Do Electricity Policy and Competitive Markets Fail to Use Advanced PV Systems to Improve Distribution Power Quality?

Directory of Open Access Journals (Sweden)

Mark P. McHenry

2016-01-01

Full Text Available The increasing pressure for network operators to meet distribution network power quality standards with increasing peak loads, renewable energy targets, and advances in automated distributed power electronics and communications is forcing policy-makers to understand new means to distribute costs and benefits within electricity markets. Discussions surrounding how distributed generation (DG exhibits active voltage regulation and power factor/reactive power control and other power quality capabilities are complicated by uncertainties of baseline local distribution network power quality and to whom and how costs and benefits of improved electricity infrastructure will be allocated. DG providing ancillary services that dynamically respond to the network characteristics could lead to major network improvements. With proper market structures renewable energy systems could greatly improve power quality on distribution systems with nearly no additional cost to the grid operators. Renewable DG does have variability challenges, though this issue can be overcome with energy storage, forecasting, and advanced inverter functionality. This paper presents real data from a large-scale grid-connected PV array with large-scale storage and explores effective mitigation measures for PV system variability. We discuss useful inverter technical knowledge for policy-makers to mitigate ongoing inflation of electricity network tariff components by new DG interconnection requirements or electricity markets which value power quality and control.
Total quality control: the deming management philosophy applied to nuclear power plants

International Nuclear Information System (INIS)

Heising, C.D.; Wetherell, D.L.; Melhem, S.A.; Sato, M.

1987-01-01

In recent years, a call has come for the development of inherently safe nuclear reactor systems that cannot have large-scale accidents. In the search for the perfect inherently safe reactor system, some are calling for the institution of computerized automated control of reactors eliminating most human operators from the control room. A different approach to the problem of the control of inherently safe reactors is that both future and present nuclear power plants need to institute total quality control (TQC) to plant operations and management. The Deming management philosophy of TQC has been implemented in a wide range of industries - particularly in Japan and the US. Specific attention is given, however, to TQC implementation in the electric power industry as applied to nuclear plants. The Kansai Electric Power Company and Florida Power and Light Company have recently implemented TQC. Statistical quality control methods have been applied to monitor and control reactor variables (for example, to the steam generator water level important to start-up operations of pressurized water reactors)
Different Modeling Aspects and Energy Systems of Unified Power Quality Conditioner (UPQC): An Overview

OpenAIRE

Deshpande, Payal; Shrivastava, Amit; Khare, Anula

2016-01-01

Abstract: This paper highlights the classification of Unified Power Quality Conditioner (UPQC) to enhance the electric power quality at distribution levels. It aims to present a broad overview on the different possible UPQC system configurations for single-phase (two-wire) and three-phase (three-wire and four-wire) networks, different modeling approaches and backup energy storages, and recent developments in the field. It is noticed that several researchers have used different names for the U...
The Quality of Accounting Earnings and Change in Political Power Map: Evidence from Indonesia

Directory of Open Access Journals (Sweden)

Harymawan Iman

2017-01-01

Full Text Available This study investigates the earnings quality of politically connected firms listed in Indonesian Stock Exchange during 2006-2010. This study compare two definition (Soeharto Dependency Index (SDI and Politically Exposed Person (PEP of political connections to capture the effect of the changes of political power map on the earnings quality of politically connected firms in Indonesia. The finding shows that the quality of accounting earnings of politically connected firms which were formerly closely related to President Soeharto in 1998 are not significantly different to other firms. Furthermore, when this study employ politically exposed person as a proxy of political connections, the findings shows that connected firms have significantly lower quality accounting earnings. Consistent with prior findings, this study shows that change in political power map in Indonesia affect the level of earnings quality of politically connected firms.
Power quality requirements and responsibilities at the point of connection

NARCIS (Netherlands)

Bhattacharyya, S.

2011-01-01

In the present power delivery environment, electricity as a product has become more competitive than before. Modern electrical devices are complex in terms of their functionalities and are more sensitive to the quality of the supplied electricity. A disturbance in supply voltage can cause
Clinical heterogeneity in newly diagnosed Parkinson's disease

NARCIS (Netherlands)

Post, Bart; Speelman, Johannes D.; de Haan, Rob J.

2008-01-01

OBJECTIVE: To determine clinical heterogeneity in newly diagnosed Parkinson's disease using cluster analysis and to describe the subgroups in terms of impairment, disability, perceived quality of life, and use of dopaminergic therapy. METHODS: We conducted a k-means cluster analysis in a prospective
Specification for a total quality assurance programme for nuclear power plants

International Nuclear Information System (INIS)

1980-01-01

This British Standard specifies principles for the establishment and implementation of quality assurance programmes during all phases of design, procurement, fabrication, construction, commissioning, operation, maintenance and decommissioning of structures, systems and components of nuclear power plants. These principles apply to activities affecting the quality of items, such as designing, purchasing, fabricating, handling, shipping, storing, cleaning, erecting, installing, testing, commissioning, operating, inspecting, maintaining, repairing, refuelling, modifying and, eventually decommissioning. (author)
Heterogeneous Monolithic Integration of Single-Crystal Organic Materials.

Science.gov (United States)

Park, Kyung Sun; Baek, Jangmi; Park, Yoonkyung; Lee, Lynn; Hyon, Jinho; Koo Lee, Yong-Eun; Shrestha, Nabeen K; Kang, Youngjong; Sung, Myung Mo

2017-02-01

Manufacturing high-performance organic electronic circuits requires the effective heterogeneous integration of different nanoscale organic materials with uniform morphology and high crystallinity in a desired arrangement. In particular, the development of high-performance organic electronic and optoelectronic devices relies on high-quality single crystals that show optimal intrinsic charge-transport properties and electrical performance. Moreover, the heterogeneous integration of organic materials on a single substrate in a monolithic way is highly demanded for the production of fundamental organic electronic components as well as complex integrated circuits. Many of the various methods that have been designed to pattern multiple heterogeneous organic materials on a substrate and the heterogeneous integration of organic single crystals with their crystal growth are described here. Critical issues that have been encountered in the development of high-performance organic integrated electronics are also addressed. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Photovoltaic Impact Assessment of Smart Inverter Volt-VAR Control on Distribution System Conservation Voltage Reduction and Power Quality

Energy Technology Data Exchange (ETDEWEB)

Ding, Fei [National Renewable Energy Lab. (NREL), Golden, CO (United States); Nagarajan, Adarsh [National Renewable Energy Lab. (NREL), Golden, CO (United States); Chakraborty, Sudipta [National Renewable Energy Lab. (NREL), Golden, CO (United States); Baggu, Murali [National Renewable Energy Lab. (NREL), Golden, CO (United States); Nguyen, Andu [SolarCity, San Mateo, CA (United States); Walinga, Sarah [SolarCity, San Mateo, CA (United States); McCarty, Michael [SolarCity, San Mateo, CA (United States); Bell, Frances [SolarCity, San Mateo, CA (United States)

2016-12-01

This report presents an impact assessment study of distributed photovoltaic (PV) with smart inverter Volt-VAR control on conservation voltage reduction (CVR) energy savings and distribution system power quality. CVR is a methodology of flattening and lowering a distribution system voltage profile in order to conserve energy. Traditional CVR relies on operating utility voltage regulators and switched capacitors. However, with the increased penetration of distributed PV systems, smart inverters provide the new opportunity to control local voltage and power factor by regulating the reactive power output, leading to a potential increase in CVR energy savings. This report proposes a methodology to implement CVR scheme by operating voltage regulators, capacitors, and autonomous smart inverter Volt-VAR control in order to achieve increased CVR benefit. Power quality is an important consideration when operating a distribution system, especially when implementing CVR. It is easy to measure the individual components that make up power quality, but a comprehensive method to incorporate all of these values into a single score has yet to be undertaken. As a result, this report proposes a power quality scoring mechanism to measure the relative power quality of distribution systems using a single number, which is aptly named the 'power quality score' (PQS). Both the CVR and PQS methodologies were applied to two distribution system models, one obtained from the Hawaiian Electric Company (HECO) and another obtained from Pacific Gas and Electric (PG&E). These two models were converted to the OpenDSS platform using previous model conversion tools that were developed by NREL. Multiple scenarios including various PV penetration levels and smart inverter densities were simulated to analyze the impact of smart inverter Volt-VAR support on CVR energy savings and feeder power quality. In order to analyze the CVR benefit and PQS, an annual simulation was conducted for each
Power-efficient computer architectures recent advances

CERN Document Server

Själander, Magnus; Kaxiras, Stefanos

2014-01-01

As Moore's Law and Dennard scaling trends have slowed, the challenges of building high-performance computer architectures while maintaining acceptable power efficiency levels have heightened. Over the past ten years, architecture techniques for power efficiency have shifted from primarily focusing on module-level efficiencies, toward more holistic design styles based on parallelism and heterogeneity. This work highlights and synthesizes recent techniques and trends in power-efficient computer architecture.Table of Contents: Introduction / Voltage and Frequency Management / Heterogeneity and Sp
Air quality assessment in the vicinity of nuclear and thermal power stations

International Nuclear Information System (INIS)

Sivaramasundaram, K.; Vijay Bhaskar, B.; Muthusubramanian, P.; Rajan, M.P.; Hegde, A.G.

2007-01-01

The status and ranking of any country, in the context of globalisation, is decided by its economic progress, which is directly linked into power generation. The power is generated by many routes and the nuclear and thermal routes are noteworthy among them. As the power production and its associated activities may cause qualitative deterioration, it is essential to study the impact of power production on atmospheric environment. In this connection, a comparative study has been carried out to assess the air quality with special reference to criteria pollutants in the vicinity of nuclear and thermal power stations. In the present investigation, the air samples are collected on weekly basis and the pollutants such as sulphur dioxide (SO 2 ), nitrogen oxides (NOx), carbon monoxide (CO), suspended particulate matter (SPM) and respirable particulate matter (RPM) are estimated by adopting standard procedures set by United States-Environmental Protection Agency (US-EPA) and Central Pollution Control Board (CPCB). As the micro meteorological parameters influence on the status of air quality, simultaneous measurements of these parameters are also carried, out during sampling. It is studied that estimated concentrations of all criteria pollutants in the vicinity of these power stations are within the permissible limits set by CPCB. On the basis of the generated database pertaining to the concentrations of criteria air pollutants in the vicinity of nuclear and thermal power stations, it is concluded that nuclear power production may be considered as a viable option in terms of environmental protection in our country. (author)
Design and control of a DSTATCOM for power quality improvement ...

African Journals Online (AJOL)

This paper presents the design of a three phase DSTATCOM (Distribution Static Compensator) and its control algorithm based on correlation and cross correlation function approach for power quality improvement under linear/ nonlinear loads in a distribution system. In this approach, an extraction of fundamental active and ...

Quality electricity lines of external power systems electric traction DC

Directory of Open Access Journals (Sweden)

A.V. Petrov

2012-08-01

Full Text Available The results of studies that compare and analyze the numerical values of some key indicators quality electricity in the lines of the external power supply system the electric traction DC. As a supplement are additional and fundamental values of energy losses in them.
Real-Time Emulation of Heterogeneous Wireless Networks with End-to-Edge Quality of Service Guarantees: The AROMA Testbed

Directory of Open Access Journals (Sweden)

Anna Umbert

2010-01-01

Full Text Available This work presents and describes the real-time testbed for all-IP Beyond 3G (B3G heterogeneous wireless networks that has been developed in the framework of the European IST AROMA project. The main objective of the AROMA testbed is to provide a highly accurate and realistic framework where the performance of algorithms, policies, protocols, services, and applications for a complete heterogeneous wireless network can be fully assessed and evaluated before bringing them to a real system. The complexity of the interaction between all-IP B3G systems and user applications, while dealing with the Quality of Service (QoS concept, motivates the development of this kind of emulation platform where different solutions can be tested in realistic conditions that could not be achieved by means of simple offline simulations. This work provides an in-depth description of the AROMA testbed, emphasizing many interesting implementation details and lessons learned during the development of the tool that may result helpful to other researchers and system engineers in the development of similar emulation platforms. Several case studies are also presented in order to illustrate the full potential and capabilities of the presented emulation platform.
Quality assurance in the field of nuclear power, international and Romanian practice

International Nuclear Information System (INIS)

Rogociu, Ioan

1997-01-01

Electricity should be generated in nuclear power plants under nuclear safety regulations with a high reliability level. In order to achieve this requirement it is necessary to work under quality assurance (QA) mode. The term of 'quality assurance' was used for the first time in USA in 1967. Since then, the situation has continuously developed. The most comprehensive standards in the fields are the USA ones. The IAEA agency in Vienna developed the first standards in 1978. The developed countries have their own legislation in the field. The IAEA standards, are based on the USA, German, Japanese, British, Canadian and French legislation. Romania drafted the Law No. 6/1982, repealed by the Law No. 11 in 1996. There is no satisfactory Romanian standard at present to regulate the activities of quality assurance in the nuclear power field. The works at Unit 1 of Cernavoda nuclear power plant were performed under the Canadian QA standards. The Canadian nuclear power company Ontario Hydro has been lately confronted with difficulties that may lead to decommission of 7 out of 19 units now in operation. To avoid the Canadian system deficiencies Romania needs standards based on the experience gained in this field by all developed countries, such as: USA, Japan, Germany, France, etc and IAEA regulations. The present paper is a pleading in favour of the Romanian legislation drafting at the level of the international demands. (author)
Power conversion and quality of the Santa Clara 2 MW direct carbonate fuel cell demonstration plant

Energy Technology Data Exchange (ETDEWEB)

Skok, A.J. [Fuel Cell Engineering Corp., Danbury, CT (United States); Abueg, R.Z. [Basic Measuring Instruments, Santa Clara, CA (United States); Schwartz, P. [Fluor Daniel, Inc., Irvine, CA (United States)] [and others

1996-12-31

The Santa Clara Demonstration Project (SCDP) is the first application of a commercial-scale carbonate fuel cell power plant on a US electric utility system. It is also the largest fuel cell power plant ever operated in the United States. The 2MW plant, located in Santa Clara, California, utilizes carbonate fuel cell technology developed by Energy Research Corporation (ERC) of Danbury, Connecticut. The ultimate goal of a fuel cell power plant is to deliver usable power into an electrical distribution system. The power conversion sub-system does this for the Santa Clara Demonstration Plant. A description of this sub-system and its capabilities follows. The sub-system has demonstrated the capability to deliver real power, reactive power and to absorb reactive power on a utility grid. The sub-system can be operated in the same manner as a conventional rotating generator except with enhanced capabilities for reactive power. Measurements demonstrated the power quality from the plant in various operating modes was high quality utility grade power.
Power and the association with relationship quality in South African couples: Implications for HIV/AIDS interventions.

Science.gov (United States)

Conroy, Amy A; McGrath, Nuala; van Rooyen, Heidi; Hosegood, Victoria; Johnson, Mallory O; Fritz, Katherine; Marr, Alexander; Ngubane, Thulani; Darbes, Lynae A

2016-03-01

Power imbalances within sexual relationships have significant implications for HIV prevention in sub-Saharan Africa. Little is known about how power influences the quality of a relationship, which could be an important pathway leading to healthy behavior around HIV/AIDS. This paper uses data from 448 heterosexual couples (896 individuals) in rural KwaZulu-Natal, South Africa who completed baseline surveys from 2012 to 2014 as part of a couples-based HIV intervention trial. Using an actor-partner interdependence perspective, we assessed: (1) how both partners' perceptions of power influences their own (i.e., actor effect) and their partner's reports of relationship quality (i.e., partner effect); and (2) whether these associations differed by gender. We examined three constructs related to power (female power, male equitable gender norms, and shared power) and four domains of relationship quality (intimacy, trust, mutually constructive communication, and conflict). For actor effects, shared power was strongly and consistently associated with higher relationship quality across all four domains. The effect of shared power on trust, mutually constructive communication, and conflict were stronger for men than women. The findings for female power and male equitable gender norms were more mixed. Female power was positively associated with women's reports of trust and mutually constructive communication, but negatively associated with intimacy. Male equitable gender norms were positively associated with men's reports of mutually constructive communication. For partner effects, male equitable gender norms were positively associated with women's reports of intimacy and negatively associated with women's reports of conflict. Research and health interventions aiming to improving HIV-related behaviors should consider sources of shared power within couples and potential leverage points for empowerment at the couple level. Efforts solely focused on empowering women should also
Power and the Association with Relationship Quality in South African Couples: Implications for HIV/AIDS Interventions

Science.gov (United States)

Conroy, Amy A.; McGrath, Nuala; van Rooyen, Heidi; Hosegood, Victoria; Johnson, Mallory O.; Fritz, Katherine; Marr, Alexander; Ngubane, Thulani; Darbes, Lynae A.

2016-01-01

Introduction Power imbalances within sexual relationships have significant implications for HIV prevention in sub-Saharan Africa. Little is known about how power influences the quality of a relationship, which could be an important pathway leading to healthy behavior around HIV/AIDS. Methods This paper uses data from 448 heterosexual couples (896 individuals) in rural KwaZulu-Natal, South Africa who completed baseline surveys from 2012–2014 as part of a couples-based HIV intervention trial. Using an actor-partner interdependence perspective, we assessed: (1) how both partners’ perceptions of power influences their own (i.e., actor effect) and their partner’s reports of relationship quality (i.e., partner effect); and (2) whether these associations differed by gender. We examined three constructs related to power (female power, male equitable gender norms, and shared power) and four domains of relationship quality (intimacy, trust, mutually constructive communication, and conflict). Results For actor effects, shared power was strongly and consistently associated with higher relationship quality across all four domains. The effect of shared power on trust, mutually constructive communication, and conflict were stronger for men than women. The findings for female power and male equitable gender norms were more mixed. Female power was positively associated with women’s reports of trust and mutually constructive communication, but negatively associated with intimacy. Male equitable gender norms were positively associated with men’s reports of mutually constructive communication. For partner effects, male equitable gender norms were positively associated with women’s reports of intimacy and negatively associated with women’s reports of conflict. Conclusions Research and health interventions aiming to improving HIV-related behaviors should consider sources of shared power within couples and potential leverage points for empowerment at the couple level
Quality assurance for pipeline installations in nuclear power plants

International Nuclear Information System (INIS)

Anon.

1983-01-01

Approximately 25% of the cost of a nuclear power plant are caused by the pipeline system, i.e. pipes and fixtures. This is an enourmous portion, demanding of the supplier and fitter of these components a very high safety standard. Against the background of the sociopolitical discussion on the safety of nuclear power plants it was a very useful idea of Mannesmann AG, one of the most important manufacturers in this sector, to lay open its quality assurance concept. On the occasion of the symposium ''Safe components for nuclear energy'' held for the expert press it was pointed out that the share of 17% electric energy coming at present from 15 nuclear power plants will increase in future for economic and ecologic reasons. So, it was maintained, the question is not about the ''pro and the con'', but exclusively about the safety standard for nuclear power plants. Specialists from the various branches of the undertaking informed on how this safety concept for the components pipelines and control equipment is realized. (orig./RW) [de
Wind resource assessment in heterogeneous terrain

Science.gov (United States)

Vanderwel, C.; Placidi, M.; Ganapathisubramani, B.

2017-03-01

High-resolution particle image velocimetry data obtained in rough-wall boundary layer experiments are re-analysed to examine the influence of surface roughness heterogeneities on wind resource. Two different types of heterogeneities are examined: (i) surfaces with repeating roughness units of the order of the boundary layer thickness (Placidi & Ganapathisubramani. 2015 J. Fluid Mech. 782, 541-566. (doi:10.1017/jfm.2015.552)) and (ii) surfaces with streamwise-aligned elevated strips that mimic adjacent hills and valleys (Vanderwel & Ganapathisubramani. 2015 J. Fluid Mech. 774, 1-12. (doi:10.1017/jfm.2015.228)). For the first case, the data show that the power extraction potential is highly dependent on the surface morphology with a variation of up to 20% in the available wind resource across the different surfaces examined. A strong correlation is shown to exist between the frontal and plan solidities of the rough surfaces and the equivalent wind speed, and hence the wind resource potential. These differences are also found in profiles of graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="RSTA20160109IM1"/> and graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="RSTA20160109IM2"/> (where U is the streamwise velocity), which act as proxies for thrust and power output. For the second case, the secondary flows that cause low- and high-momentum pathways when the spacing between adjacent hills is beyond a critical value result in significant variations in wind resource availability. Contour maps of graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="RSTA20160109IM3"/> and graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="RSTA20160109IM4"/> show a large difference in thrust and power potential (over 50%) between hills and valleys (at a fixed vertical height). These variations do not seem to be present when adjacent hills are close to each other (i.e. when the spacing is much less than the boundary layer thickness). The
Design of dynamic power quality monitoring and fault diagnosis system of ship-power system based on Ethernet

Directory of Open Access Journals (Sweden)

HU Hongqian

2018-02-01

Full Text Available [Objectives] According to situation that the ship power information exchange system based on the traditional field bus has been unable to meet the needs of modern ship power system for informatization, automation, intelligent and safe operation. [Methods] This paper proposes the use of industrial Ethernet Modbus/TCP to make up for lack of field-bus. Then, the data center is established by collecting the inherent data of the field bus of the combined ship power system and collecting the real-time data from the online measurement device based on the Modbus/TCP. Correlation theory and neural network intelligent algorithm are used to analyze big data to complete the dynamic power quality monitoring and fault diagnosis of ship power system. [Results] Finally, the man-machine interface is designed with LabVIEW. [Conclusions] The feasibility of the software and hardware implementation of the scheme is verified by the laboratory platform.
Heterogeneous characters modeling of instant message services users' online behavior.

Directory of Open Access Journals (Sweden)

Hongyan Cui

Full Text Available Research on temporal characteristics of human dynamics has attracted much attentions for its contribution to various areas such as communication, medical treatment, finance, etc. Existing studies show that the time intervals between two consecutive events present different non-Poisson characteristics, such as power-law, Pareto, bimodal distribution of power-law, exponential distribution, piecewise power-law, et al. With the occurrences of new services, new types of distributions may arise. In this paper, we study the distributions of the time intervals between two consecutive visits to QQ and WeChat service, the top two popular instant messaging services in China, and present a new finding that when the value of statistical unit T is set to 0.001s, the inter-event time distribution follows a piecewise distribution of exponential and power-law, indicating the heterogeneous character of IM services users' online behavior in different time scales. We infer that the heterogeneous character is related to the communication mechanism of IM and the habits of users. Then we develop a combination model of exponential model and interest model to characterize the heterogeneity. Furthermore, we find that the exponent of the inter-event time distribution of the same service is different in two cities, which is correlated with the popularity of the services. Our research is useful for the application of information diffusion, prediction of economic development of cities, and so on.
Heterogeneous characters modeling of instant message services users’ online behavior

Science.gov (United States)

Fang, Yajun; Horn, Berthold

2018-01-01

Research on temporal characteristics of human dynamics has attracted much attentions for its contribution to various areas such as communication, medical treatment, finance, etc. Existing studies show that the time intervals between two consecutive events present different non-Poisson characteristics, such as power-law, Pareto, bimodal distribution of power-law, exponential distribution, piecewise power-law, et al. With the occurrences of new services, new types of distributions may arise. In this paper, we study the distributions of the time intervals between two consecutive visits to QQ and WeChat service, the top two popular instant messaging services in China, and present a new finding that when the value of statistical unit T is set to 0.001s, the inter-event time distribution follows a piecewise distribution of exponential and power-law, indicating the heterogeneous character of IM services users’ online behavior in different time scales. We infer that the heterogeneous character is related to the communication mechanism of IM and the habits of users. Then we develop a combination model of exponential model and interest model to characterize the heterogeneity. Furthermore, we find that the exponent of the inter-event time distribution of the same service is different in two cities, which is correlated with the popularity of the services. Our research is useful for the application of information diffusion, prediction of economic development of cities, and so on. PMID:29734327
Adaptive neuro-fuzzy and expert systems for power quality analysis and prediction of abnormal operation

Science.gov (United States)

Ibrahim, Wael Refaat Anis

The present research involves the development of several fuzzy expert systems for power quality analysis and diagnosis. Intelligent systems for the prediction of abnormal system operation were also developed. The performance of all intelligent modules developed was either enhanced or completely produced through adaptive fuzzy learning techniques. Neuro-fuzzy learning is the main adaptive technique utilized. The work presents a novel approach to the interpretation of power quality from the perspective of the continuous operation of a single system. The research includes an extensive literature review pertaining to the applications of intelligent systems to power quality analysis. Basic definitions and signature events related to power quality are introduced. In addition, detailed discussions of various artificial intelligence paradigms as well as wavelet theory are included. A fuzzy-based intelligent system capable of identifying normal from abnormal operation for a given system was developed. Adaptive neuro-fuzzy learning was applied to enhance its performance. A group of fuzzy expert systems that could perform full operational diagnosis were also developed successfully. The developed systems were applied to the operational diagnosis of 3-phase induction motors and rectifier bridges. A novel approach for learning power quality waveforms and trends was developed. The technique, which is adaptive neuro fuzzy-based, learned, compressed, and stored the waveform data. The new technique was successfully tested using a wide variety of power quality signature waveforms, and using real site data. The trend-learning technique was incorporated into a fuzzy expert system that was designed to predict abnormal operation of a monitored system. The intelligent system learns and stores, in compressed format, trends leading to abnormal operation. The system then compares incoming data to the retained trends continuously. If the incoming data matches any of the learned trends, an
Knowledge, Power and Meanings Shaping Quality Assurance in Higher Education: A Systemic Critique

Science.gov (United States)

Houston, Don; Paewai, Shelley

2013-01-01

Internationally, quality assurance schemes persist despite long-standing dissatisfaction and critique of their impact and outcomes. Adopting a critical systems perspective, the article explores the relationships between the knowledge, power and meanings that stakeholder groups bring to the design and implementation of quality assurance systems.…
Quality factors quantification/assurance for software related to safety in nuclear power plants

International Nuclear Information System (INIS)

Nunez McLeod, J.E.; Rivera, S.S.

1997-01-01

Quality assurance plan is needed to guarantee the software quality. The use of such a plan involves activities that should take place all along the life cycle, and which can be evaluated using the so called quality factors. This is due to the fact that the quality itself cannot be measured, but some of its manifestations can be used for this purpose. In the present work, a methodology to quantify a set of quality factors is proposed, for software based systems to be used in safety related areas in nuclear power plants. (author) [es
Design of Energy Storage Control Strategy to Improve the PV System Power Quality

DEFF Research Database (Denmark)

Lei, Mingyu; Yang, Zilong; Wang, Yibo

2016-01-01

Random fluctuation of PV power is becoming a more and more serious problem affecting the power quality and stability of grid as the PV penetration keeps increasing recent years. Aiming at this problem, this paper proposed a control strategy of energy storage system based on Model Predictive Contr...
Resource management for heterogeneous networks in LTE systems

CERN Document Server

Hu, Rose Qingyang

2014-01-01

This SpringerBrief provides an in-depth look at the key issues that affect the performance of heterogeneous networks and presents schemes that can effectively tackle these issues. In particular, this book discusses unbalanced traffic load among the macro and micro Base Stations (BSs) caused by the transmit power disparity, and a load-balancing based mobile association scheme to balance the traffic load among the macro and micro BSs. This book also introduces a fractional frequency reuse (FFR) scheme with proper power control to help reduce interference at the UEs which are most vulnerable to such intra-cell interference. The last section investigates radio resource allocation issues for heterogeneous networks with cooperative relays, and proposes a resource allocation framework that could achieve proportional fairness among the UEs. Numerical results are provided to demonstrate the effectiveness of the proposed solutions in tackling the problem and improving network performance. Resource Management for Hetero...
Cooperative Radio Resource Management for Heterogeneous Networks

DEFF Research Database (Denmark)

Mihovska, Albena D.; Tragos, Elias; Luo, Jijun

2009-01-01

The heterogeneity in technology and also in ownership leads to complex systems and interworking problems, which can be seen from the ability to establish and maintain connections with required quality, in fault detection and location, in resource allocation and in charging of the usage of the net...
Project quality management under EPC mode by the owner of nuclear power plant

International Nuclear Information System (INIS)

Xu Hui; Hu Miao

2014-01-01

As the first completely independent nuclear power project in China, Fangjiashan nuclear power project is constructed under EPC mode of general project contracting. This paper, taking the project as an example, aims to explore how the project owners carry out quality management for the installation project during the construction of the nuclear power plant based on EPC mode. It has certain reference value for the management of following nuclear power projects which adopting the EPC construction mode. It will play a positive role in improving China's overall self-management abilities in the nuclear power construction, and lay a solid foundation for follow-up nuclear power construction in China. (authors)
Cooperative Control of Multi-Master-Slave Islanded Microgrid with Power Quality Enhancement Based on Conservative Power Theory

DEFF Research Database (Denmark)

Mortezaei, Ali; Simoes, Marcelo; Savaghebi, Mehdi

2018-01-01

Cooperative control of power converters in a microgrid offers power quality enhancement at sensitive load buses. Such cooperation is particularly important in the presence of reactive, nonlinear and unbalanced loads. In this paper, a multi-master-slave-based control of Distributed Generators (DGs...... in a selective control strategy able to share each current component with desired percentage among the microgrid inverters. Simulation results are presented to demonstrate the effectiveness of the proposed method.......) interface converters in a three-phase four-wire islanded microgrid using the Conservative Power Theory (CPT) is proposed. Inverters located in close proximity operate as a group in master-salve mode. Slaves inject the available energy and compensate selectively unwanted current components of local loads...
Diode pumped 1kHz high power Nd:YAG laser with excellent beam quality

NARCIS (Netherlands)

Godfried, Herman; Godfried, H.P; Offerhaus, Herman L.

1997-01-01

The design and operation of a one kilohertz diode pumped all solid-state Nd:YAG master oscillator power amplifier system with a phase conjugate mirror is presented. The setup allows high power scaling without reduction in beam quality.

Heterogeneous policies, heterogeneous technologies: The case of renewable energy

International Nuclear Information System (INIS)

Nicolli, Francesco; Vona, Francesco

2016-01-01

This paper investigates empirically the effect of market regulation and renewable energy policies on innovation activity in different renewable energy technologies. For the EU countries and the years 1980 to 2007, we built a unique dataset containing information on patent production in eight different technologies, proxies of market regulation and technology-specific renewable energy policies. Our main finding is that, compared to privatisation and unbundling, reducing entry barriers is a more significant driver of renewable energy innovation, but that its effect varies across technologies and is stronger in technologies characterised by potential entry of small, independent power producers. In addition, the inducement effect of renewable energy policies is heterogeneous and more pronounced for wind, which is the only technology that is mature and has high technological potential. Finally, ratification of the Kyoto protocol, which determined a more stable and less uncertain policy framework, amplifies the inducement effect of both energy policy and market liberalisation. - Highlights: • We study the effect of market regulation and energy policy on renewable technologies. • Reducing entry barriers is a significant driver of renewable energy innovation. • The Kyoto protocol amplifies the effect of both energy policy and liberalisation. • These effects are heterogeneous across technologies and stronger for wind.
Tracking of Power Quality Indicators during Wind Farm Islanding Experiment

DEFF Research Database (Denmark)

Terzija, V.; Crossley, P.A.; Stanojevic, V.

2007-01-01

The application of the two-stage Newton Type Algorithm for the tracking of the power quality indicators (in accordance with IEEE Standard 1459-2000) is presented in the paper. To estimate their spectra and fundamental frequency, the current and voltage signals are first processed and then the pow...... experiment in Denmark....
Detection and classification of power quality disturbances using S-transform and modular neural network

Energy Technology Data Exchange (ETDEWEB)

Bhende, C.N.; Mishra, S.; Panigrahi, B.K. [Department of Electrical Engineering, Indian Institute of Technology, New Delhi 110016 (India)

2008-01-15

This paper presents an S-transform based modular neural network (NN) classifier for recognition of power quality disturbances. The excellent time - frequency resolution characteristics of the S-transform makes it an attractive candidate for the analysis of power quality (PQ) disturbances under noisy condition and has the ability to detect the disturbance correctly. On the other hand, the performance of wavelet transform (WT) degrades while detecting and localizing the disturbances in the presence of noise. Features extracted by using the S-transform are applied to a modular NN for automatic classification of the PQ disturbances that solves a relatively complex problem by decomposing it into simpler subtasks. Modularity of neural network provides better classification, model complexity reduction and better learning capability, etc. Eleven types of PQ disturbances are considered for the classification. The simulation results show that the combination of the S-transform and a modular NN can effectively detect and classify different power quality disturbances. (author)
Theoretical Investigation For The Effect of Fuel Quality on Gas Turbine Power Plants

Science.gov (United States)

AbdulRazzak khudair, Omar; Alwan Abass, Khetam; Saadi Abed, Noor; Hussain Ali, Khalid; AbdulAziz, Saad; Chlaib Shaboot, Ali

2018-05-01

Gas turbine engine power generation is declined dramatically because of the reduction in thermodynamic parameters as a work of turbine, compressor ratio, compressor work, and air mass flow rate and fuel consumption. There are two main objectives of this work, the first is related with the effect of fuel kinds and their quality on the operation of fuel flow divider and its performance specifically gear pump displacement and fuel flow rate to the combustion chambers of gas power plant. AL-DORA gas turbine power plant 35MW was chosen to predict these effects on its performance MATLAB Software program is used to perform thermodynamic calculations. Fuel distribution stage before the process of combustion and as a result of the kind and its quality, chemical reaction will occur between the fuel and the parts of the gear system of each pump of the flow divider, which causes the erosion of the internal pump wall and the teeth of the gear system, thus hampering the pump operation in terms of fuel discharge. The discharge of fuel form the eight external gates of flow divider is decreased and varied when going to the combustion chambers, so that, flow divider does not give reliable mass flow rate due to absence of accurate pressure in each of eight exit pipes. The second objective deals with the stage of fuel combustion process inside the combustion chamber. A comparative study based upon performance parameters, such as specific fuel consumption for gas and gasoil and power generation. Fuel poor quality causes incomplete combustion and increased its consumption, so that combustion products are interacted with the surface of the turbine blades, causing the erosion and create surface roughness of the blade and disruption of gas flow. As a result of this situation, turbulence flow of these gases will increase causing the separation of gas boundary layers over the suction surface of the blade. Therefore the amount of extracted gas will decrease causing retreat work done by
A GPS-Based Control Method for Load Sharing and Power Quality Improvement in Microgrids

DEFF Research Database (Denmark)

Golsorkhi, Mohammad; Lu, Dylan; Savaghebi, Mehdi

2016-01-01

This paper proposes a novel control method for accurate sharing of load current among the Distributed Energy Resources (DER) and high power quality operating in islanded ac microgrids. This control scheme is based on hierarchical structure comprising of decentralized primary controllers and a cen....... The secondary controller produces compensation signals at fundamental and dominant harmonics to improve the voltage quality at a sensitive load bus. Experimental results are presented to validate the efficacy of the proposed method.......This paper proposes a novel control method for accurate sharing of load current among the Distributed Energy Resources (DER) and high power quality operating in islanded ac microgrids. This control scheme is based on hierarchical structure comprising of decentralized primary controllers...
Enhanced power quality based single phase photovoltaic distributed generation system

Science.gov (United States)

Panda, Aurobinda; Pathak, M. K.; Srivastava, S. P.

2016-08-01

This article presents a novel control strategy for a 1-ϕ 2-level grid-tie photovoltaic (PV) inverter to enhance the power quality (PQ) of a PV distributed generation (PVDG) system. The objective is to obtain the maximum benefits from the grid-tie PV inverter by introducing current harmonics as well as reactive power compensation schemes in its control strategy, thereby controlling the PV inverter to achieve multiple functions in the PVDG system such as: (1) active power flow control between the PV inverter and the grid, (2) reactive power compensation, and (3) grid current harmonics compensation. A PQ enhancement controller (PQEC) has been designed to achieve the aforementioned objectives. The issue of underutilisation of the PV inverter in nighttime has also been addressed in this article and for the optimal use of the system; the PV inverter is used as a shunt active power filter in nighttime. A prototype model of the proposed system is developed in the laboratory, to validate the effectiveness of the control scheme, and is tested with the help of the dSPACE DS1104 platform.
Quality assurance for nuclear power stations in Japan

International Nuclear Information System (INIS)

Nitta, Y.

1984-01-01

The quality assurance programmes of the Japanese industry show some special features, both in the nuclear field and in non-nuclear technology. Among them e.g. the meticulous care given by Japanese workers to their work and duties, and the high training level and skill of employees in the development and other departments. Another important feature is the common practice of Japanese firms, to guarantee lifetime employment to workers and employees. The quality assurance programme for nuclear power plants covers such aspects as basic design features, detailed planning and construction, fuel element fabrication, basic research, licensing and operation. The responsibility for efficient execution of the programmes lies with the administration, the utilities, the suppliers, as well as all other contractors to a project. The tasks to be fulfilled by organisations, firms, etc., are briefly explained. (orig./HSCH) [de
Manufacture and quality control of concrete for Ikata Nuclear Power Station, Shikoku Electric Power Co., Inc

International Nuclear Information System (INIS)

Tada, Akiomi; Kitada, Takao

1989-01-01

Ikata Nuclear Power Station, only one nuclear power station in Shikoku, is located at the root of Sada Peninsula on Seto Inland sea side. At present, No.1 and No.2 plants of 566 MW each are in commercial operation, and on the east side, No.3 plant is under construction. No.3 plant is a PWR type plant of 890 MWe output, and the start of commercial operation is scheduled in March, 1995. In the construction of No.3 plant, the concrete used for civil engineering and building works is about 430,000 m 3 , and for the improvement of the quality control of concrete, the pursuit of economic efficiency, the fostering of concrete technology of employee and the coprosperity with local industries, the facilities for manufacturing concrete were constructed within the premise of the power station. The amount of use of concrete and respective materials classified by respective fiscal years, and the amount of manufacture of concrete that determines the scale of the concrete plant are shown. As to the construction of the concrete plant, the foundation work was started in March, 1987, and the machine foundation and building works were started in May, 1987. The acceptance was completed on August 17, 1987. The facilities of manufacturing concrete, the manufacture of concrete, and the quality control of materials and concrete are reported. (author)
Studying on the problem of quality, ability and adult education of the management personnel of nuclear power library and information

International Nuclear Information System (INIS)

Ma Hua

2012-01-01

Studying on how to improve the quality and ability of the nuclear power library and information management personnel has an important role in the promotion of nuclear power industry and the development of nuclear power library and information. By the view of the perspective of the development of nuclear power industry and the improvement of quality and level of nuclear power library and information. The library and information management personnel of nuclear power in the new period should have seven types of basic quality and ability. Vigorously developing adult education is an effective way to comprehensively improve the quality and ability of the nuclear power library and information management personnel. Doing well in adult education must grasp some key issues: put ideological and moral education first, regard pertinence and effectiveness and innovate ways and methods of education. (author)
High throughput screening method for assessing heterogeneity of microorganisms

NARCIS (Netherlands)

Ingham, C.J.; Sprenkels, A.J.; van Hylckama Vlieg, J.E.T.; Bomer, Johan G.; de Vos, W.M.; van den Berg, Albert

2006-01-01

The invention relates to the field of microbiology. Provided is a method which is particularly powerful for High Throughput Screening (HTS) purposes. More specific a high throughput method for determining heterogeneity or interactions of microorganisms is provided.
Quality assurance as a system of management control in nuclear power plants

International Nuclear Information System (INIS)

Raisic, N.

1986-04-01

Quality assurance is considered as a management control system which the owner of a nuclear power plant has to establish for a nuclear power project for ensuring that a plant is built as designed and that defects are corrected. The building up of such a system should start early enough in project activities and before the plant design and construction, in order to ensure correct performance of all activities related to selection of the site for the nuclear power plant, bid specification and evaluation and procurement of services. The QA is a regulatory requirement, but the prudent plant management would create such a system as part of their total project management systems irrespective of formulation of requirement. In fact regulatory requirement should be considered as the criteria to be used by the regulatory organization for evaluation of licensee's QA system and not as an objective to be reached. In this paper the needs for QA system are justified as part of the development of industrial infrastructure for the nuclear power project. Elements of the system are described such as documented QA programme and organizational structures with defined responsibility and functions of individual organizational units, and with control of information flow across the interfaces. The goals and objectives or the project organizations related to achievement and verification of quality are defined as well as system functions in attaining these objectives. This includes the feedback of information to the management on monitoring of performance in project activities, identifying deficiencies and initiating corrective actions. Domestic participation in the nuclear power plant construction will depend on the ability of local construction and manufacturing organizations to achieve high quality standards of products and services that can affect safety and performance of the nuclear power plant. Introduction of QA systems in project organizations, development of QA programme and
Quality assurance in the design of nuclear power plants

International Nuclear Information System (INIS)

1981-01-01

This Safety Guide provides the requirements and recommendations related to the establishment and implementation of quality assurance for design of items for a nuclear power plant. The requirements of this Guide shall be applied to the extent necessary during all constituent activities of the nuclear power plant project, such as design, manufacture, construction, commissioning and operations. Its requirements and recommendations shall be implemented, as appropriate, by the responsible organization or by its designated representatives: by plant designers, architect-engineers or manufacturers, when involved in performing design activities related to items to be manufactured; by site constructors, when involved in field engineering activities; by plant operators and other organizations, when involved in design activities related to plant modifications or to selection of spare or replacement parts; and by design consultants and other technical organizations, when performing any engineering activity that affects the work of other design organizations during various stages of nuclear power plant projects
Understanding coal quality and its relationship to power plant performance and costs

Energy Technology Data Exchange (ETDEWEB)

Jennison, K.D.; Stallard, G.S. [Black & Veatch International, Overland Park, KS (United States)

1995-12-01

The availability of reliable, reasonably priced energy is a necessary cornerstone for established and emerging economies. In addition to addressing coal quality issues strictly at a plant level, it is now prudent to consider long-term performance and economics of particular fuel sources to be selected in the light of system economics and reliability. In order to evaluate coal quality issues in a more comprehensive manner, it is important to develop both an approach and a set of tools which can support the various phases of the planning/analysis processes. The processes must consider the following: (1) Cost/availability of other potential coal supplies, including {open_quotes}raw{close_quotes} domestic sources, {open_quotes}cleaned {close_quotes} domestic sources, and other internationally marketed coals. (2) Power plant performance issues as function of plant design and fuel properties. (3) System expansion plans, candidate technologies, and associated capital and operating costs. (4) Projected load demand, for system and for individual units within the system. (5) Legislative issues such as environmental pressures, power purchase agreements, etc. which could alter the solution. (6) Economics of potential plans/strategies based on overall cost-effectiveness of the utility system, not just individual units. (7) Anticipated unit configuration, including addition of environmental control equipment or other repowering options. The Coal Quality Impact Model (CQIM{trademark}) is a PC-based computer program capable of predicting coal-related cost and performance impacts at electric power generating sites. The CQIM was developed for EPRI by Black & Veatch and represents over a decade of effort geared toward developing an extensible state-of-the-art coal quality assessment tool. This paper will introduce CQIM, its capabilities, and its application to Eastern European coal quality assessment needs.
Quality and performance of laser cutting with a high power SM fiber laser

DEFF Research Database (Denmark)

Kristiansen, Morten; Selchau, Jacob; Olsen, F. O.

2013-01-01

The introduction of high power single mode fiber lasers allows for a beam of high power and a good beam quality factor (M2 ” 1.2), compared to the multimode fiber lasers often utilised in macro laser metal cutting. This paper describes fundamental studies of macro laser metal cutting with a singl...
Genomics meets applied ecology: Characterizing habitat quality for sloths in a tropical agroecosystem.

Science.gov (United States)

Fountain, Emily D; Kang, Jung Koo; Tempel, Douglas J; Palsbøll, Per J; Pauli, Jonathan N; Zachariah Peery, M

2018-01-01

Understanding how habitat quality in heterogeneous landscapes governs the distribution and fitness of individuals is a fundamental aspect of ecology. While mean individual fitness is generally considered a key to assessing habitat quality, a comprehensive understanding of habitat quality in heterogeneous landscapes requires estimates of dispersal rates among habitat types. The increasing accessibility of genomic approaches, combined with field-based demographic methods, provides novel opportunities for incorporating dispersal estimation into assessments of habitat quality. In this study, we integrated genomic kinship approaches with field-based estimates of fitness components and approximate Bayesian computation (ABC) procedures to estimate habitat-specific dispersal rates and characterize habitat quality in two-toed sloths (Choloepus hoffmanni) occurring in a Costa Rican agricultural ecosystem. Field-based observations indicated that birth and survival rates were similar in a sparsely shaded cacao farm and adjacent cattle pasture-forest mosaic. Sloth density was threefold higher in pasture compared with cacao, whereas home range size and overlap were greater in cacao compared with pasture. Dispersal rates were similar between the two habitats, as estimated using ABC procedures applied to the spatial distribution of pairs of related individuals identified using 3,431 single nucleotide polymorphism and 11 microsatellite locus genotypes. Our results indicate that crops produced under a sparse overstorey can, in some cases, constitute lower-quality habitat than pasture-forest mosaics for sloths, perhaps because of differences in food resources or predator communities. Finally, our study demonstrates that integrating field-based demographic approaches with genomic methods can provide a powerful means for characterizing habitat quality for animal populations occurring in heterogeneous landscapes. © 2017 John Wiley & Sons Ltd.
Food away from home and body mass outcomes: taking heterogeneity into account enhances quality of results.

Science.gov (United States)

Kim, Tae Hyun; Lee, Eui-Kyung; Han, Euna

2014-09-01

The aim of this study was to explore the heterogeneous association of consumption of food away from home (FAFH) with individual body mass outcomes including body mass index and waist circumference over the entire conditional distribution of each outcome. Information on 16,403 adults obtained from nationally representative data on nutrition and behavior in Korea was used. A quantile regression model captured the variability of the association of FAFH with body mass outcomes across the entire conditional distribution of each outcome measure. Heavy FAFH consumption was defined as obtaining ≥1400 kcal from FAFH on a single day. Heavy FAFH consumption, specifically at full-service restaurants, was significantly associated with higher body mass index (+0.46 kg/m2 at the 50th quantile, 0.55 at the 75th, 0.66 at the 90th, and 0.44 at the 95th) and waist circumference (+0.96 cm at the 25th quantile, 1.06 cm at the 50th, 1.35 cm at the 75th, and 0.96 cm at the 90th quantiles) with overall larger associations at higher quantiles. Findings of the study indicate that conventional regression methods may mask important heterogeneity in the association between heavy FAFH consumption and body mass outcomes. Further public health efforts are needed to improve the nutritional quality of affordable FAFH choices and nutrition education and to establish a healthy food consumption environment. Copyright © 2014 Elsevier Inc. All rights reserved.
Solar-Powered Plasmon-Enhanced Heterogeneous Catalysis

Directory of Open Access Journals (Sweden)

Naldoni Alberto

2016-06-01

Full Text Available Photocatalysis uses semiconductors to convert sunlight into chemical energy. Recent reports have shown that plasmonic nanostructures can be used to extend semiconductor light absorption or to drive direct photocatalysis with visible light at their surface. In this review, we discuss the fundamental decay pathway of localized surface plasmons in the context of driving solar-powered chemical reactions. We also review different nanophotonic approaches demonstrated for increasing solar-to-hydrogen conversion in photoelectrochemical water splitting, including experimental observations of enhanced reaction selectivity for reactions occurring at the metalsemiconductor interface. The enhanced reaction selectivity is highly dependent on the morphology, electronic properties, and spatial arrangement of composite nanostructures and their elements. In addition, we report on the particular features of photocatalytic reactions evolving at plasmonic metal surfaces and discuss the possibility of manipulating the reaction selectivity through the activation of targeted molecular bonds. Finally, using solar-to-hydrogen conversion techniques as an example, we quantify the efficacy metrics achievable in plasmon-driven photoelectrochemical systems and highlight some of the new directions that could lead to the practical implementation of solar-powered plasmon-based catalytic devices.
Effect of power quality on windings temperature of marine induction motors. Part II: Results of investigations and recommendations for related regulations

International Nuclear Information System (INIS)

Gnacinski, P.; Mindykowski, J.; Tarasiuk, T.

2009-01-01

This paper deals with the effect of lowered voltage quality in ship power systems on windings temperature of low-power induction cage machines. The results of investigations carried out with experimental and analytical methods are presented. The thermal impact of power quality disturbances permitted by ship classification societies is discussed. A proposal of new power quality regulations for ship classification societies is made.
Study on quality control measures of static casting main pipe in PWR nuclear power plant

International Nuclear Information System (INIS)

Jiang Zhenbiao; Li Guanying; Liu Zhicheng

2013-01-01

This study analyzes the main reasons which impact the quality of primary pipe static casting elbows in PWR-M310 nuclear power plant. The quality control measures are developed from the election and inspection of material, improving sand production and casting process, improving lean management of personnel. The static casting defects of primary pipe elbows for Fuqing Unit 1 and 2 were down to less than 50% of the former project. The quality of static casting for the primary pipe elbows was significantly improved. Moreover, the implementation saves human resources and financing to repair casting defects, and also helps to win the delivery schedule. The quality control measures are good reference for improving primary pipe casting process. This study provides valuable experience for further study of improving the quality of static casting for the primary pipe of PWR nuclear power plant. (authors)
Competing Air Quality and Water Conservation Co-benefits from Power Sector Decarbonization

Science.gov (United States)

Peng, W.; Wagner, F.; Mauzerall, D. L.; Ramana, M. V.; Zhai, H.; Small, M.; Zhang, X.; Dalin, C.

2016-12-01

Decarbonizing the power sector can reduce fossil-based generation and associated air pollution and water use. However, power sector configurations that prioritize air quality benefits can be different from those that maximize water conservation benefits. Despite extensive work to optimize the generation mix under an air pollution or water constraint, little research has examined electricity transmission networks and the choice of which fossil fuel units to displace in order to achieve both environmental objectives simultaneously. When air pollution and water stress occur in different regions, the optimal transmission and displacement decisions still depend on priorities placed on air quality and water conservation benefits even if low-carbon generation planning is fixed. Here we use China as a test case, and develop a new optimization framework to study transmission and displacement decisions and the resulting air quality and water use impacts for six power sector decarbonization scenarios in 2030 ( 50% of national generation is low carbon). We fix low-carbon generation in each scenario (e.g. type, location, quantity) and vary technology choices and deployment patterns across scenarios. The objective is to minimize the total physical costs (transmission costs and coal power generation costs) and the estimated environmental costs. Environmental costs are estimated by multiplying effective air pollutant emissions (EMeff, emissions weighted by population density) and effective water use (Weff, water use weighted by a local water stress index) by their unit economic values, Vem and Vw. We are hence able to examine the effect of varying policy priorities by imposing different combinations of Vem and Vw. In all six scenarios, we find that increasing the priority on air quality co-benefits (higher Vem) reduces air pollution impacts (lower EMeff) at the expense of lower water conservation (higher Weff); and vice versa. Such results can largely be explained by differences

A medium-term coalition-forming model of heterogeneous DERs for a commercial virtual power plant

International Nuclear Information System (INIS)

Shabanzadeh, Morteza; Sheikh-El-Eslami, Mohammad-Kazem; Haghifam, Mahmoud-Reza

2016-01-01

Highlights: • A medium-term coalition-forming scheme is proposed for commercial VPPs. • Decision making on the optimal selection of VPP coalition members, bilateral and forward contracting, and pool involvement. • VPP acts as an arbitrageur by exercising arbitrage between diverse energy trading floors. • Stochastic programming approach applied to characterize the uncertainty and to derive informed decisions. - Abstract: Within a medium-term market horizon, this research work provides a methodology that allows a commercial virtual power plant (CVPP) to form an optimal coalition of heterogeneous distributed energy resources (DERs) based on weekly bilateral contracting, futures-market involvement, and pool participation. The established model aims at composing an optimal portfolio of available DERs and jointly takes into account the risk associated with the energy trading strategy of the CVPP. Perceiving the fact that pool prices have highly uncertain nature, a framework based on stochastic programming approach is utilized to model this decision-making problem. The proposed framework consists of two stages. The first stage deals with decisions regarding DERs optimal selection for the VPP coalition, the amount of agreed quantity in the bilateral negotiation, and the type and quantity selection of futures-market contracts as well. In the second stage, decisions are made based on the most plausible realizations of the stochastic prices in the day-ahead market. For a given pre-specified risk level on profit volatility, the main objective is to maximize the expected profit for the VPP manager over the planning horizon. The efficiency and applicability of the developed model is illustrated and analyzed by its implementation in a system with few heterogeneous DERs and through different scenarios, and finally thereby meaningful conclusions are duly drawn.
Integrated approach for power quality requirements at the point of connection

NARCIS (Netherlands)

Cobben, J.F.G.; Bhattacharyya, S.; Myrzik, J.M.A.; Kling, W.L.

2007-01-01

Given the nature of electricity, every party connected to the power system influences voltage quality, which means that every party also should meet requirements. In this field, a sound coordination among technical standards (system-related, installation-related and product-related) is of paramount
Quality assurance requirements for the operation of Swedish nuclear power plants

International Nuclear Information System (INIS)

1983-09-01

An adaption of NRC's 10 CFR 50, Appendis B (Quality Assurance Criteria for Nuclear Power and Fuel Reprocessing Plants) to Swedish conditions is presented. No references are given to regulations standards etc that influence the requirements and their adaption to local conditions. (Aa)
ANALYZER OF QUANTITY AND QUALITY OF THE ELECTRIC POWER

Directory of Open Access Journals (Sweden)

A. I. Semilyak

2013-01-01

Full Text Available One of the activities of the research center for “Energy Saving Technologies and Smart Metering in Electrical Power Engineering" is research work on the use of electronic devices and systems of intelligent power distribution, produced by Analog Devices and equipped with the accurate energy consumption measurement feature. The article focuses on the development of the analyzer of quantity and quality of electric energy.The main part of the analyzer is a metering IC by Analog Devices ADE7878, designed for use in commercial and industrial smart electricity meters. Such counters measure the amount of consumed or produced electric energy with high accuracy and have the means of remote meter reading.
On the Efficient Broadcasting of Heterogeneous Services over Band-Limited Channels: Unequal Power Allocation for Wavelet Packet Division Multiplexing

Directory of Open Access Journals (Sweden)

Maurizio Murroni

2008-01-01

Full Text Available Multiple transmission of heterogeneous services is a central aspect of broadcasting technology. Often, in this framework, the design of efficient communication systems is complicated by stringent bandwidth constraint. In wavelet packet division multiplexing (WPDM, the message signals are waveform coded onto wavelet packet basis functions. The overlapping nature of such waveforms in both time and frequency allows improving the performance over the commonly used FDM and TDM schemes, while their orthogonality properties permit to extract the message signals by a simple correlator receiver. Furthermore, the scalable structure of WPDM makes it suitable for broadcasting heterogeneous services. This work investigates unequal error protection (UEP of data which exhibit different sensitivities to channel errors to improve the performance of WPDM for transmission over band-limited channels. To cope with bandwidth constraint, an appropriate distribution of power among waveforms is proposed which is driven by the channel error sensitivities of the carried message signals in case of Gaussian noise. We address this problem by means of the genetic algorithms (GAs, which allow flexible suboptimal solution with reduced complexity. The mean square error (MSE between the original and the decoded message, which has a strong correlation with subjective perception, is used as an optimization criterion.
Effect of power quality on windings temperature of marine induction motors. Part II: Results of investigations and recommendations for related regulations

Energy Technology Data Exchange (ETDEWEB)

Gnacinski, P.; Mindykowski, J.; Tarasiuk, T. [Gdynia Maritime Univ., Dept. of Ship Electrical Power Engineering, Morska Str. 83, 81-225 Gdynia (Poland)

2009-10-15

This paper deals with the effect of lowered voltage quality in ship power systems on windings temperature of low-power induction cage machines. The results of investigations carried out with experimental and analytical methods are presented. The thermal impact of power quality disturbances permitted by ship classification societies is discussed. A proposal of new power quality regulations for ship classification societies is made. (author)
Modeling and simulation of heterogeneous catalytic processes

CERN Document Server

Dixon, Anthony

2014-01-01

Heterogeneous catalysis and mathematical modeling are essential components of the continuing search for better utilization of raw materials and energy, with reduced impact on the environment. Numerical modeling of chemical systems has progressed rapidly due to increases in computer power, and is used extensively for analysis, design and development of catalytic reactors and processes. This book presents reviews of the state-of-the-art in modeling of heterogeneous catalytic reactors and processes. Reviews by leading authorities in the respective areas Up-to-date reviews of latest techniques in modeling of catalytic processes Mix of US and European authors, as well as academic/industrial/research institute perspectives Connections between computation and experimental methods in some of the chapters.
On the area spectral efficiency improvement of heterogeneous network by exploiting the integration of macro-femto cellular networks

KAUST Repository

Shakir, Muhammad

2012-06-01

Heterogeneous networks are an attractive means of expanding mobile network capacity. A heterogeneous network is typically composed of multiple radio access technologies (RATs) where the base stations are transmitting with variable power. In this paper, we consider a Heterogeneous network where we complement the macrocell network with low-power low-cost user deployed nodes, such as femtocell base stations to increase the mean achievable capacity of the system. In this context, we integrate macro-femto cellular networks and derive the area spectral efficiency of the proposed two tier Heterogeneous network. We consider the deployment of femtocell base stations around the edge of the macrocell such that this configuration is referred to as femto-on-edge (FOE) configuration. Moreover, FOE configuration mandates reduction in intercell interference due to the mobile users which are located around the edge of the macrocell since these femtocell base stations are low-power nodes which has significantly lower transmission power than macrocell base stations. We present a mathematical analysis to calculate the instantaneous carrier to interference ratio (CIR) of the desired mobile user in macro and femto cellular networks and determine the total area spectral efficiency of the Heterogeneous network. Details of the simulation processes are included to support the analysis and show the efficacy of the proposed deployment. It has been shown that the proposed setup of the Heterogeneous network offers higher area spectral efficiency which aims to fulfill the expected demand of the future mobile users. © 2012 IEEE.
Environmental Quality and the U.S. Power Sector: Air Quality, Land Use and Environmental Justice

Energy Technology Data Exchange (ETDEWEB)

Massetti, Emanuele [Georgia Inst. of Technology, Atlanta, GA (United States); Brown, Marilyn Ann [Georgia Inst. of Technology, Atlanta, GA (United States); Lapsa, Melissa Voss [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Sharma, Isha [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Bradbury, James [U.S. Dept. of Energy, Washington, DC (United States); Cunliff, Colin [American Association for the Advancement of Science, Washington, DC (United States); Li, Yufei [Georgia Inst. of Technology, Atlanta, GA (United States)

2017-01-04

This baseline report summarizes key environmental quality issues associated with electricity generation, transmission, distribution, and end use in the United States. Its scope includes non-greenhouse gas air pollution (i.e., sulfur dioxide, nitrogen oxides, particulate matter and hazardous air pollutants), land use, water pollution, ecological impacts, human health, and environmental justice. The discussion characterizes both current impacts and recent trends, as well as assessments of key drivers of change. For example, the air emissions section includes a quantitative decomposition analysis of the drivers of change in sulfur dioxide emissions reductions from coal-fired power plants. The report is divided into four topical sections: air emissions, land use and ecology, water quality, and environmental justice.
A versatile omnibus test for detecting mean and variance heterogeneity.

Science.gov (United States)

Cao, Ying; Wei, Peng; Bailey, Matthew; Kauwe, John S K; Maxwell, Taylor J

2014-01-01

Recent research has revealed loci that display variance heterogeneity through various means such as biological disruption, linkage disequilibrium (LD), gene-by-gene (G × G), or gene-by-environment interaction. We propose a versatile likelihood ratio test that allows joint testing for mean and variance heterogeneity (LRT(MV)) or either effect alone (LRT(M) or LRT(V)) in the presence of covariates. Using extensive simulations for our method and others, we found that all parametric tests were sensitive to nonnormality regardless of any trait transformations. Coupling our test with the parametric bootstrap solves this issue. Using simulations and empirical data from a known mean-only functional variant, we demonstrate how LD can produce variance-heterogeneity loci (vQTL) in a predictable fashion based on differential allele frequencies, high D', and relatively low r² values. We propose that a joint test for mean and variance heterogeneity is more powerful than a variance-only test for detecting vQTL. This takes advantage of loci that also have mean effects without sacrificing much power to detect variance only effects. We discuss using vQTL as an approach to detect G × G interactions and also how vQTL are related to relationship loci, and how both can create prior hypothesis for each other and reveal the relationships between traits and possibly between components of a composite trait.
Research on detecting heterogeneous fibre from cotton based on linear CCD camera

Science.gov (United States)

Zhang, Xian-bin; Cao, Bing; Zhang, Xin-peng; Shi, Wei

2009-07-01

The heterogeneous fibre in cotton make a great impact on production of cotton textile, it will have a bad effect on the quality of product, thereby affect economic benefits and market competitive ability of corporation. So the detecting and eliminating of heterogeneous fibre is particular important to improve machining technics of cotton, advance the quality of cotton textile and reduce production cost. There are favorable market value and future development for this technology. An optical detecting system obtains the widespread application. In this system, we use a linear CCD camera to scan the running cotton, then the video signals are put into computer and processed according to the difference of grayscale, if there is heterogeneous fibre in cotton, the computer will send an order to drive the gas nozzle to eliminate the heterogeneous fibre. In the paper, we adopt monochrome LED array as the new detecting light source, it's lamp flicker, stability of luminous intensity, lumens depreciation and useful life are all superior to fluorescence light. We analyse the reflection spectrum of cotton and various heterogeneous fibre first, then select appropriate frequency of the light source, we finally adopt violet LED array as the new detecting light source. The whole hardware structure and software design are introduced in this paper.
A GPS-Based Control Framework for Accurate Current Sharing and Power Quality Improvement in Microgrids

DEFF Research Database (Denmark)

Golsorkhi, Mohammad; Savaghebi, Mehdi; Lu, Dylan

2017-01-01

This paper proposes a novel hierarchical control strategy for improvement of load sharing and power quality in ac microgrids. This control framework is composed of a droop based controller at the primary level, and a combination of distributed power sharing and voltage conditioning schemes...... consensus protocol to ensure proportional sharing of average power. The voltage conditioning scheme produces compensation signals at fundamental and dominant harmonics to improve the voltage quality at a sensitive load bus. Experimental results are presented to validate the efficacy of the proposed method....... dynamic response. The droop coefficient, which acts as a virtual resistance is adaptively changed as a function of the peak current. This strategy not only simplifies the control design but also improves the current sharing accuracy at high loading conditions. The distributed power sharing scheme uses...
Quality assurance systems - a means for an integrating organization of nuclear power plants

International Nuclear Information System (INIS)

Adams, H.W.

1984-01-01

The operators of nuclear power plants are in the process of introducing quality assurance systems of the type required in Rule 1401 by the German Kerntechnischer Ausschuss (Nuclear Technology Committee). These systems as a cross sectional function cover most of the organizational areas of a nuclear power plant. Their introduction offers an opportunity to harmonize and supplement existing systems where necessary. Integrated quality assurance systems built up on a data base allow existing DP data and other logical data to be organized in such a way that certain sequences of events can be managed by enforced control. This relieves the personnel responsible for the safety of a nuclear power plant of routine jobs and routine decisions. Greater flexibility is created for personal decisions. Organized sequences of events can be monitored by having lists printed out in which the necessary data are combined into data sets. (orig.) [de
Heterogeneous self-assembled media for biopolymerization

DEFF Research Database (Denmark)

Monnard, Pierre-Alain

2011-01-01

Heterogeneous media, such as micro-structured aqueous environments, could offer an alternative approach to the synthesis of biopolymers with novel functions. Structured media are here defined as specialized, self-assembled structures that are formed, e.g, by amphiphiles, such as liposomes, emulsion...... polymerization, the initial elongation rates clearly depended on the complementarity of the monomers with the templating nucleobases3. However, metal-ion catalyzed reactions deliver RNA analogs with heterogeneous linkages. Moreover, the usefulness of this medium in the form of quasi-compartmentalization extends...... beyond metal-ion catalysis reactions, as we have recently demonstrated the catalytic power of a dipeptide, SerHis, for the regioselective formation of phosphodiester bonds. These results in conjonction with the synthesis of nucleobases at -78˚C, the demonstration of ribozyme activity (RNA ligase ribozyme...
Methods for slow axis beam quality improvement of high power broad area diode lasers

Science.gov (United States)

An, Haiyan; Xiong, Yihan; Jiang, Ching-Long J.; Schmidt, Berthold; Treusch, Georg

2014-03-01

For high brightness direct diode laser systems, it is of fundamental importance to improve the slow axis beam quality of the incorporated laser diodes regardless what beam combining technology is applied. To further advance our products in terms of increased brightness at a high power level, we must optimize the slow axis beam quality despite the far field blooming at high current levels. The later is caused predominantly by the built-in index step in combination with the thermal lens effect. Most of the methods for beam quality improvements reported in publications sacrifice the device efficiency and reliable output power. In order to improve the beam quality as well as maintain the efficiency and reliable output power, we investigated methods of influencing local heat generation to reduce the thermal gradient across the slow axis direction, optimizing the built-in index step and discriminating high order modes. Based on our findings, we have combined different methods in our new device design. Subsequently, the beam parameter product (BPP) of a 10% fill factor bar has improved by approximately 30% at 7 W/emitter without efficiency penalty. This technology has enabled fiber coupled high brightness multi-kilowatt direct diode laser systems. In this paper, we will elaborate on the methods used as well as the results achieved.
Earthquake ground-motion in presence of source and medium heterogeneities

KAUST Repository

Vyas, Jagdish Chandra

2017-01-01

This dissertation work investigates the effects of earthquake rupture complexity and heterogeneities in Earth structure on near-field ground-motions. More specifically, we address two key issues in seismology: (1) near-field ground-shaking variability as function of distance and azimuth for unilateral directive ruptures, and (2) impact of rupture complexity and seismic scattering on Mach wave coherence associated with supershear rupture propagation. We examine earthquake ground-motion variability associated with unilateral ruptures based on ground-motion simulations of the MW 7.3 1992 Landers earthquake, eight simplified source models, and a MW 7.8 rupture simulation (ShakeOut) for the San Andreas fault. Our numerical modeling reveals that the ground-shaking variability in near-fault distances (< 20 km) is larger than that given by empirical ground motion prediction equations. In addition, the variability decreases with increasing distance from the source, exhibiting a power-law decay. The high near-field variability can be explained by strong directivity effects whose influence weaken as we move away from the fault. At the same time, the slope of the power-law decay is found to be dominantly controlled by slip heterogeneity. Furthermore, the ground-shaking variability is high in the rupture propagation direction whereas low in the directions perpendicular to it. However, the variability expressed as a function of azimuth is not only sensitive to slip heterogeneity, but also to rupture velocity. To study Mach wave coherence for supershear ruptures, we consider heterogeneities in rupture parameters (variations in slip, rise time and rupture speed) and 3D scattering media having small-scale random heterogeneities. The Mach wave coherence is reduced at near-fault distances (< 10 km) by the source heterogeneities. At the larger distances from the source, medium scattering plays the dominant role in reducing the Mach wave coherence. Combined effect of the source and
Hospital heterogeneity: what drives the quality of health care.

Science.gov (United States)

Ali, Manhal; Salehnejad, Reza; Mansur, Mohaimen

2018-04-01

A major feature of health care systems is substantial variation in health care quality across hospitals. The quality of stroke care widely varies across NHS hospitals. We investigate factors that may explain variations in health care quality using measures of quality of stroke care. We combine NHS trust data from the National Sentinel Stroke Audit with other data sets from the Office for National Statistics, NHS and census data to capture hospitals' human and physical assets and organisational characteristics. We employ a class of non-parametric methods to explore the complex structure of the data and a set of correlated random effects models to identify key determinants of the quality of stroke care. The organisational quality of the process of stroke care appears as a fundamental driver of clinical quality of stroke care. There are rich complementarities amongst drivers of quality of stroke care. The findings strengthen previous research on managerial and organisational determinants of health care quality.
Rupture dynamics and ground motions from earthquakes in 2-D heterogeneous media

KAUST Repository

Bydlon, Samuel A.

2015-03-21

©2015. American Geophysical Union. All Rights Reserved. We perform 2-D simulations of earthquakes on rough faults in media with random heterogeneities (with von Karman distribution) to study the effects of geometric and material heterogeneity on the rupture process and resulting high-frequency ground motions in the near-fault region (out to ∼20km). Variations in slip and rupture velocity can arise from material heterogeneity alone but are dominantly controlled by fault roughness. Scattering effects become appreciable beyond ∼3km from the fault. Near-fault scattering extends the duration of incoherent, high-frequency ground motions and, at least in our 2-D simulations, elevates root-mean-square accelerations (i.e., Arias intensity) with negligible reduction in peak velocities. We also demonstrate that near-fault scattering typically occurs in the power law tail of the power spectral density function, quantified by the Hurst exponent and another parameter combining standard deviation and correlation length. Key Points Fault roughness, not material heterogeneity, dominates rupture process Introduce parameter that can be used to quantify near-fault scattering Scattering affects the duration and amplitude of high-frequency ground motions
Quality assurance requirements for the reliability of nuclear power plants in developing countries

International Nuclear Information System (INIS)

Bhutta, S.M.

1978-01-01

Quality Assurance (QA) has not been taken very seriously in developing countries despite their having significant nuclear power programmes. This may affect plant reliability and demands that urgent and serious attention be given to the development and implementation of Quality Assurance programmes according to local conditions. Confusion has been created by the differences in definitions and interpretations of terminologies of Quality Assurance and Control. Problems have been aggravated by the lack of clearly defined responsibilities and accountabilities during the projects execution phases of site selection, data collection, design, equipment fabrication and construction, etc. Therefore, reliability of nuclear power plants in developing countries is relatively low. But whenever some programme of QA has been implemented it has helped to improve the plant performance. This is highlighted in this paper by the practical examples for the experience of Karachi Nuclear Power Plant whose forced outages have been reduced by over a half within a period of 3 years. In view of the benefits, a QA programme for Chashma Nuclear Power Project has also been initiated. In this paper urgency is emphasized for the establishment and implementation of a formal QA programme in the developing countries if the reactor suppliers and purchasers both want to ensure higher reliability of their plants. The best way that management can play its role effectively is by setting up a strong QA organization with local personnel, thus helping to attain self-reliance and higher reliability during plant operation. (author)
Quality assurance for safety in nuclear power plants. A code of practice

International Nuclear Information System (INIS)

1978-01-01

The Code of Practice is a part of the International Atomic Energy Agency's programme, referred to as the NUSS programme (Nuclear Safety Standards), for establishing Codes of Practice and Safety Guides relating to land-based stationary thermal neutron power plants. The documents are based on documentation and experience from various national systems and practices. The present document provides the recommended principles and objectives for the establishment and implementation of a quality assurance programme during design, manufacture, construction, commissioning and operation of structures, system and components important to safety. They are applicable by all those responsible for the power plant, by plant designers, suppliers, architect-engineers, plant constructors, plant operators and other organizations participating in activities affecting quality. The Lists of relevant definition and the Provisional List of NUSS Programme Titles are given

Agent-based Distributed Unbalance Compensation for Optimal Power Quality in Islanded Microgrids

DEFF Research Database (Denmark)

Meng, Lexuan; Dragicevic, Tomislav; Guerrero, Josep M.

2014-01-01

-based distributed hierarchical control method. Communication links are required between neighboring units. Consensus algorithm and optimization algorithm are implemented in tertiary control for global information discovery and local optimal decision-making respectively. The tertiary control gives lower level......In microgrids, the distributed generators (DG) can be used as distributed compensators so as to compensate the voltage unbalances in the critical bus. However, the power quality disturbance in generator sides and local buses may be affected and exceeds the limit. It can be more convenient...... to implement tertiary control so as to adjust the compensation efforts among DGs and ensure the acceptable power quality in local buses. Moreover, as centralized control methods have certain disadvantages, such as low flexibility, expandability and heavy computation burden, this paper proposes an agent...
The selective application of quality assurance activities to nuclear power plant items and services

International Nuclear Information System (INIS)

Anderson, J.W.

1982-01-01

The definition of quality assurance and the criteria for a quality assurance programme that are contained in both national and international codes and standards provide the principle of selective application of quality assurance activities for cost-effective results. The effective implementation of this principle requires a systematic and disciplined methodology that should be established by or for the owner at the beginning of a nuclear power plant project. The methodology that has proven to be successful generally includes a uniform method of classifying plant items and services at their lowest level of unit assembly and using that classification in the selection of applicable quality assurance activities and the specification of appropriate requirements for those activities. The applicable quality assurance activities are those to be implemented by the organizations designing, manufacturing, installing and operating plant items or performing support services. The methods and techniques provided illustrate the methodology and are one way by which a nuclear power plant project may translate the principle into application in order to achieve the desired results. (author)
A new approach for power quality improvement of DFIG based wind farms connected to weak utility grid

Directory of Open Access Journals (Sweden)

Hossein Mahvash

2017-09-01

Full Text Available Most of power quality problems for grid connected doubly fed induction generators (DFIGs with wind turbine include flicker, variations of voltage RMS profile, and injected harmonics due to switching in DFIG converters. Flicker phenomenon is the most important problem in wind power systems. This paper described an effective method for mitigating flicker emission and power quality improvement for a fairly weak grid connected to a wind farm with DFIGs. The method was applied in the rotor side converter (RSC of the DFIG to control the output reactive power. q axis reference current was directly derived according to the mathematical relation between rotor q axis current and DFIG output reactive power without using PI controller. To extract the reference reactive power, the stator voltage control loop with the droop coefficient was proposed to regulate the grid voltage level in each operational condition. The DFIG output active power was separately controlled in d axis considering the stator voltage orientation control (SVOC. Different simulations were carried out on the test system and the flicker short term severity index (Pst was calculated for each case study using the discrete flickermeter model according to IEC 61400 standard. The obtained results validated flicker mitigation and power quality enhancement for the grid.
Quality assurance in the construction of nuclear power plants

International Nuclear Information System (INIS)

Bernsen, S.A.

1975-01-01

A general survey of quality-assurance (QA) practices as they relate to the construction phase of nuclear power plants is presented. The article briefly outlines the evolution of construction QA requirements, describes construction practices and organizational relations that help identify the unique construction-phase features that affect QA practices, identifies some of the principal requirements and programmatic problems involving construction, and discusses potential trends and suggested guidelines for the implementation of particular practices. (U.S.)
Manual on quality assurance for installation and commissioning of instrumentation, control and electrical equipment in nuclear power plants

International Nuclear Information System (INIS)

1989-01-01

The present Manual on Quality Assurance (QA) for Installation and Commissioning of Instrumentation, Control and Electrical (ICE) Equipment of Nuclear Power Plants contains supporting material and illustrative examples for implementing basic requirements of the quality assurance programme in procurement, receiving, installation and commissioning of this equipment. The Manual on Quality Assurance for Installation and Commissioning of ICE Equipment is designed to supplement and be consistent with the Guidebook as well as with the IAEA Code and Safety Guides on Quality Assurance. It is intended for the use of managerial staff and QA personnel of nuclear power plant owners or the organizations respectively responsible for the legal, technical, administrative and financial aspects of a nuclear power plant. The information provided in the Manual will also be useful to the inspection staff of the regulatory organization in the planning and performance of regulatory inspections at nuclear power plants
The system of quality assurance of EDF for designing and developing nuclear power plants

International Nuclear Information System (INIS)

Vaujour, M.

As the quality required for a power plant must fulfill at one and the same time, performance, safety and reliability criteria, the quality obtainment needs the establishment of a system of quality assurance: an internal system of arrangement of the organizations involved, measures creating the relations between said organizations, mechanisms of control of the quality organizing, and some statements. The respective roles of EDF and the constructors are defined together with the contractual obligations of the constructors [fr
Air quality analysis for the Western Area Power Administration's 2004 Power Marketing Plan Environmental Impact Statement

International Nuclear Information System (INIS)

Glantz, C.S.; Dagle, J.E.; Bilyard, G.R.

1997-01-01

The Western Area Power Administration (Western) markets and transmits electric power throughout 15 western states. Western's Sierra Nevada Customer Service Region (Sierra Nevada Region) markets approximately 1,480 megawatts (MW) of firm power (plus 100 MW of seasonal peaking capacity) from the Central Valley Project (CVP) and other resources. Western's mission is to sell and deliver electricity generated from these resources. Western's capacity and energy sales must be in conformance with the laws that govern its sale of electrical power. Further, Western's hydropower operations at each facility must comply with minimum and maximum flows and other constraints set by other regulatory agencies. The Sierra Nevada Region proposes to develop a marketing plan that defines the products and services it would offer beyond the year 2004 and the eligibility and allocation criteria for its electric power resources. Because determining levels of long-term firm power resources to be marketed and subsequently entering into contracts for the delivery of related products and services could be a major Federal action with potentially significant impacts to the human environment, the 2004 Power Marketing Plan Environmental Impact Statement (2004 EIS) is being prepared. Decisions made by the Sierra Nevada Region on how and when to supply power to its customers would influence the operation of power plants within the Western Systems Coordinating Council (WSCC). If the resources affected are thermal resources, this could in turn affect the amount, timing, and location of pollutant emissions to the air at locations throughout the western United States. This report has been produced in conjunction with the 2004 EIS to provide a more detailed discussion of the air quality implications of the 2004 power marketing plan
Statistical characterization of Earth’s heterogeneities from seismic scattering

Science.gov (United States)

Zheng, Y.; Wu, R.

2009-12-01

The distortion of a teleseismic wavefront carries information about the heterogeneities through which the wave propagates and it is manifestited as logarithmic amplitude (logA) and phase fluctuations of the direct P wave recorded by a seismic network. By cross correlating the fluctuations (e.g., logA-logA or phase-phase), we obtain coherence functions, which depend on spatial lags between stations and incident angles between the incident waves. We have mathematically related the depth-dependent heterogeneity spectrum to the observable coherence functions using seismic scattering theory. We will show that our method has sharp depth resolution. Using the HiNet seismic network data in Japan, we have inverted power spectra for two depth ranges, ~0-120km and below ~120km depth. The coherence functions formed by different groups of stations or by different groups of earthquakes at different back azimuths are similar. This demonstrates that the method is statistically stable and the inhomogeneities are statistically stationary. In both depth intervals, the trend of the spectral amplitude decays from large scale to small scale in a power-law fashion with exceptions at ~50km for the logA data. Due to the spatial spacing of the seismometers, only information from length scale 15km to 200km is inverted. However our scattering method provides new information on small to intermediate scales that are comparable to scales of the recycled materials and thus is complimentary to the global seismic tomography which reveals mainly large-scale heterogeneities on the order of ~1000km. The small-scale heterogeneities revealed here are not likely of pure thermal origin. Therefore, the length scale and strength of heterogeneities as a function of depth may provide important constraints in mechanical mixing of various components in the mantle convection.
Quality control for the construction of Ikata Nuclear Power Station No. 2 Unit

International Nuclear Information System (INIS)

Onishi, Akiyoshi

1983-01-01

In the construction of No. 2 unit in Ikata Nuclear Power Station, Shikoku Electric Power Co., the quality control was practiced making effective use of the experience in preceding stations including the Three Mile Island station, U.S., and improving those. The construction works were also performed in consideration of ensuring the safe running of No. 1 unit in commercial operation. In this report, first the outline of No. 2 unit facility and the quality control in the construction processes are described sequentially. For the comprehensive quality control activity over a series of plant design, manufacturing, installation and commissioning processes, the quality control policy was fixed, the system was established, the plan was prepared, and the quality control was promoted as planned and systematically. The outline of the quality control in each stage is described as follows. Design stage: It was implemented for the confirmation of applicable standards and references, the management of drawings submitted for approval, the selection of materials used, the coordination among sub-contractors, design change and the reflection of experience in preceding stations. Manufacturing stage. It was performed for material control, manufacturing management, factory test and control. Installation stage. It was practiced for the management of installation works, the inspection during the installation, and the check-up and control after the installation. Several quality control items were implemented also in the method of construction works and construction management. (Wakatsuki, Y.)
Quality factors in the life cycle of software oriented to safety systems in nuclear power plants

International Nuclear Information System (INIS)

Nunez McLeod, J.E.; Rivera, S.S.

1997-01-01

The inclusion of software in safety related systems for nuclear power plants, makes it necessary to include the software quality assurance concept. The software quality can be defined as the adjustment degree between the software and the specified requirements and user expectations. To guarantee a certain software quality level it is necessary to make a systematic and planned set of tasks, that constitute a software quality guaranty plan. The application of such a plan involves activities that should be performed all along the software life cycle, and that can be evaluated through the so called quality factors, due to the fact that the quality itself cannot be directly measured, but indirectly as some of it manifestations. In this work, a software life cycle model is proposed, for nuclear power plant safety related systems. A set os software quality factors is also proposed , with its corresponding classification according to the proposed model. (author) [es
Control scheme towards enhancing power quality and operational efficiency of single-phase two-stage grid-connected photovoltaic systems

Directory of Open Access Journals (Sweden)

Mahmoud Salem

2015-12-01

Full Text Available Achieving high reliable grid-connected photovoltaic (PV systems with high power quality and high operation efficiency is highly required for distributed generation units. A double grid-frequency voltage ripple is found on the dc-link voltage in single-phase photovoltaic grid-connected systems due to the unbalance of the instantaneous dc input and ac output powers. This voltage ripple has undesirable effects on the power quality and operational efficiency of the whole system. Harmonic distortion in the injected current to the grid is one of the problems caused by this double grid-frequency voltage ripple. The double grid frequency ripple propagates to the PV voltage and current which disturb the extracted maximum power from the PV array. This paper introduces intelligent solutions towards mitigate the side effects of the double grid-frequency voltage ripple on the transferred power quality and the operational efficiency of single-phase two-stage grid-connected PV system. The proposed system has three control loops: MPPT control loop, dc-link voltage control loop and inverter current control loop. Solutions are introduced for all the three control loops in the system. The current controller cancels the dc-link voltage effect on the total harmonic distortion of the output current. The dc-link voltage controller is designed to generate a ripple free reference current signal that leads to enhance the quality of the output power. Also a modified MPPT controller is proposed to optimize the extracted power from the PV array. Simulation results show that higher injected power quality is achieved and higher efficiency of the overall system is realized.
Heterogeneous game resource distributions promote cooperation in spatial prisoner's dilemma game

Science.gov (United States)

Cui, Guang-Hai; Wang, Zhen; Yang, Yan-Cun; Tian, Sheng-Wen; Yue, Jun

2018-01-01

In social networks, individual abilities to establish interactions are always heterogeneous and independent of the number of topological neighbors. We here study the influence of heterogeneous distributions of abilities on the evolution of individual cooperation in the spatial prisoner's dilemma game. First, we introduced a prisoner's dilemma game, taking into account individual heterogeneous abilities to establish games, which are determined by the owned game resources. Second, we studied three types of game resource distributions that follow the power-law property. Simulation results show that the heterogeneous distribution of individual game resources can promote cooperation effectively, and the heterogeneous level of resource distributions has a positive influence on the maintenance of cooperation. Extensive analysis shows that cooperators with large resource capacities can foster cooperator clusters around themselves. Furthermore, when the temptation to defect is high, cooperator clusters in which the central pure cooperators have larger game resource capacities are more stable than other cooperator clusters.
The effect of thermal de-phasing on the beam quality of a high-power single-pass second harmonic generation

Science.gov (United States)

Sadat Hashemi, Somayeh; Ghavami Sabouri, Saeed; Khorsandi, Alireza

2018-04-01

We present a theoretical model in order to study the effect of a thermally loaded crystal on the quality of a second-harmonic (SH) beam generated in a high-power pumping regime. The model is provided based on using a particular structure of oven considered for MgO:PPsLT nonlinear crystal to compensate for the thermal de-phasing effect that as the pumping power reaches up to 50 W degrades the conversion efficiency and beam quality of the interacting beams. Hereupon, the quality of fundamental beam is involved in the modeling to investigate the final effect on the beam quality of generated SH beam. Beam quality evaluation is subsequently simulated using Hermite-Gaussian modal decomposition approach for a range of fundamental beam qualities varied from 1 to 3 and for different levels of input powers. To provide a meaningful comparison numerical simulation is correlated with real data deduced from a high-power SH generation (SHG) experimental device. It is found that when using the open-top oven scheme and fixing the fundamental M 2-factor at nearly 1, for a range of input powers changing from 15 to 30 W, the M 2-factor of SHG beam is degraded from 9% to 24%, respectively, confirming very good consistency with the reported experimental results.
DESIGN OF DYNAMIC VOLTAGE RESTORER TO ENHANCE POWER QUALITY RELYING ON RENEWABLE SOURCE

Directory of Open Access Journals (Sweden)

Haider M. Umran

2018-05-01

Full Text Available Power quality improvement of low voltage grid is a great challenge that confronts the sophisticated power applications, because their performance is highly sensitive to the quality of power supply. Dynamic Voltage Restorer (DVR used widely as an efficient and skillful device to adjust electrical disturbances of the distribution grids. This paper introduces an overview of the components of the 3-phase dynamic voltage restorer and design its own control circuit. The performance of DVR was developed on the basis of the appropriate selection of Photovoltaic (PV module instead of the present conventional designs. Through this design, the need of series converter (DVR for the current from an electrical grid will end and the problems of power losses will curb. The PV-module is selected to meet the requirements of the DVR during voltage sag/swell on voltage line. The proposed system is mimicked in MATLAB software/Simulink and the findings are presented to prove the success of the design in terms of: Full congruence of the load voltage waveform with source voltage waveform, attaining 0.77% of THD analysis for the load voltage and the waveforms of PV system.
Studying and simulating transformer configuration to improve power quality

Directory of Open Access Journals (Sweden)

Oscar J. Peña Huaringa

2011-06-01

Full Text Available This paper presents a study and simulation of transformer configurations to improve power quality; it provides theoretical support based on the expansion of the Fourier series and analysis of symmetrical components. A test system was set up in the laboratory, taking measurements and checking configuration effectiveness in reducing the system’s harmonic content. The configurations were modelled with PSCAD / EMTDC software, using two 6 pulse rectifiers as test loads and two variable speed drives.
Power quality events recognition using a SVM-based method

Energy Technology Data Exchange (ETDEWEB)

Cerqueira, Augusto Santiago; Ferreira, Danton Diego; Ribeiro, Moises Vidal; Duque, Carlos Augusto [Department of Electrical Circuits, Federal University of Juiz de Fora, Campus Universitario, 36036 900, Juiz de Fora MG (Brazil)

2008-09-15

In this paper, a novel SVM-based method for power quality event classification is proposed. A simple approach for feature extraction is introduced, based on the subtraction of the fundamental component from the acquired voltage signal. The resulting signal is presented to a support vector machine for event classification. Results from simulation are presented and compared with two other methods, the OTFR and the LCEC. The proposed method shown an improved performance followed by a reasonable computational cost. (author)
Combined Power Quality Disturbances Recognition Using Wavelet Packet Entropies and S-Transform

Directory of Open Access Journals (Sweden)

Zhigang Liu

2015-08-01

Full Text Available Aiming at the combined power quality +disturbance recognition, an automated recognition method based on wavelet packet entropy (WPE and modified incomplete S-transform (MIST is proposed in this paper. By combining wavelet packet Tsallis singular entropy, energy entropy and MIST, a 13-dimension vector of different power quality (PQ disturbances including single disturbances and combined disturbances is extracted. Then, a ruled decision tree is designed to recognize the combined disturbances. The proposed method is tested and evaluated using a large number of simulated PQ disturbances and some real-life signals, which include voltage sag, swell, interruption, oscillation transient, impulsive transient, harmonics, voltage fluctuation and their combinations. In addition, the comparison of the proposed recognition approach with some existing techniques is made. The experimental results show that the proposed method can effectively recognize the single and combined PQ disturbances.
Large epidemic thresholds emerge in heterogeneous networks of heterogeneous nodes

Science.gov (United States)

Yang, Hui; Tang, Ming; Gross, Thilo

2015-08-01

One of the famous results of network science states that networks with heterogeneous connectivity are more susceptible to epidemic spreading than their more homogeneous counterparts. In particular, in networks of identical nodes it has been shown that network heterogeneity, i.e. a broad degree distribution, can lower the epidemic threshold at which epidemics can invade the system. Network heterogeneity can thus allow diseases with lower transmission probabilities to persist and spread. However, it has been pointed out that networks in which the properties of nodes are intrinsically heterogeneous can be very resilient to disease spreading. Heterogeneity in structure can enhance or diminish the resilience of networks with heterogeneous nodes, depending on the correlations between the topological and intrinsic properties. Here, we consider a plausible scenario where people have intrinsic differences in susceptibility and adapt their social network structure to the presence of the disease. We show that the resilience of networks with heterogeneous connectivity can surpass those of networks with homogeneous connectivity. For epidemiology, this implies that network heterogeneity should not be studied in isolation, it is instead the heterogeneity of infection risk that determines the likelihood of outbreaks.
Large epidemic thresholds emerge in heterogeneous networks of heterogeneous nodes.

Science.gov (United States)

Yang, Hui; Tang, Ming; Gross, Thilo

2015-08-21

One of the famous results of network science states that networks with heterogeneous connectivity are more susceptible to epidemic spreading than their more homogeneous counterparts. In particular, in networks of identical nodes it has been shown that network heterogeneity, i.e. a broad degree distribution, can lower the epidemic threshold at which epidemics can invade the system. Network heterogeneity can thus allow diseases with lower transmission probabilities to persist and spread. However, it has been pointed out that networks in which the properties of nodes are intrinsically heterogeneous can be very resilient to disease spreading. Heterogeneity in structure can enhance or diminish the resilience of networks with heterogeneous nodes, depending on the correlations between the topological and intrinsic properties. Here, we consider a plausible scenario where people have intrinsic differences in susceptibility and adapt their social network structure to the presence of the disease. We show that the resilience of networks with heterogeneous connectivity can surpass those of networks with homogeneous connectivity. For epidemiology, this implies that network heterogeneity should not be studied in isolation, it is instead the heterogeneity of infection risk that determines the likelihood of outbreaks.
Viscosity of Heterogeneous Silicate Melts: A Non-Newtonian Model

Science.gov (United States)

Liu, Zhuangzhuang; Blanpain, Bart; Guo, Muxing

2017-12-01

The recently published viscosity data of heterogeneous silicate melts with well-documented structure and experimental conditions are critically re-analyzed and tabulated. By using these data, a non-Newtonian viscosity model incorporating solid fraction, solid shape, and shear rate is proposed on the basis of the power-law equation. This model allows calculating the viscosity of the heterogeneous silicate melts with solid fraction up to 34 vol pct. The error between the calculated and measured data is evaluated to be 32 pct, which is acceptable considering the large error in viscosity measurement of the completely liquid silicate melt.

Real-time video streaming in mobile cloud over heterogeneous wireless networks

Science.gov (United States)

Abdallah-Saleh, Saleh; Wang, Qi; Grecos, Christos

2012-06-01

Recently, the concept of Mobile Cloud Computing (MCC) has been proposed to offload the resource requirements in computational capabilities, storage and security from mobile devices into the cloud. Internet video applications such as real-time streaming are expected to be ubiquitously deployed and supported over the cloud for mobile users, who typically encounter a range of wireless networks of diverse radio access technologies during their roaming. However, real-time video streaming for mobile cloud users across heterogeneous wireless networks presents multiple challenges. The network-layer quality of service (QoS) provision to support high-quality mobile video delivery in this demanding scenario remains an open research question, and this in turn affects the application-level visual quality and impedes mobile users' perceived quality of experience (QoE). In this paper, we devise a framework to support real-time video streaming in this new mobile video networking paradigm and evaluate the performance of the proposed framework empirically through a lab-based yet realistic testing platform. One particular issue we focus on is the effect of users' mobility on the QoS of video streaming over the cloud. We design and implement a hybrid platform comprising of a test-bed and an emulator, on which our concept of mobile cloud computing, video streaming and heterogeneous wireless networks are implemented and integrated to allow the testing of our framework. As representative heterogeneous wireless networks, the popular WLAN (Wi-Fi) and MAN (WiMAX) networks are incorporated in order to evaluate effects of handovers between these different radio access technologies. The H.264/AVC (Advanced Video Coding) standard is employed for real-time video streaming from a server to mobile users (client nodes) in the networks. Mobility support is introduced to enable continuous streaming experience for a mobile user across the heterogeneous wireless network. Real-time video stream packets
Z-Source-Inverter-Based Flexible Distributed Generation System Solution for Grid Power Quality Improvement

DEFF Research Database (Denmark)

Blaabjerg, Frede; Vilathgamuwa, D. M.; Loh, Poh Chiang

2009-01-01

Distributed generation (DG) systems are usually connected to the grid using power electronic converters. Power delivered from such DG sources depends on factors like energy availability and load demand. The converters used in power conversion do not operate with their full capacity all the time......-stage buck-boost inverter, recently proposed Z-source inverter (ZSI) is a good candidate for future DG systems. This paper presents a controller design for a ZSI-based DG system to improve power quality of distribution systems. The proposed control method is tested with simulation results obtained using...
Heterogeneous Wireless Mesh Network Technology Evaluation for Space Proximity and Surface Applications

Science.gov (United States)

DeCristofaro, Michael A.; Lansdowne, Chatwin A.; Schlesinger, Adam M.

2014-01-01

NASA has identified standardized wireless mesh networking as a key technology for future human and robotic space exploration. Wireless mesh networks enable rapid deployment, provide coverage in undeveloped regions. Mesh networks are also self-healing, resilient, and extensible, qualities not found in traditional infrastructure-based networks. Mesh networks can offer lower size, weight, and power (SWaP) than overlapped infrastructure-perapplication. To better understand the maturity, characteristics and capability of the technology, we developed an 802.11 mesh network consisting of a combination of heterogeneous commercial off-the-shelf devices and opensource firmware and software packages. Various streaming applications were operated over the mesh network, including voice and video, and performance measurements were made under different operating scenarios. During the testing several issues with the currently implemented mesh network technology were identified and outlined for future work.
Quality control of the structural design of Angra 2 and 3 power reactor

International Nuclear Information System (INIS)

Merino, J.L.E.; Carvalho, S.R.B. de

1985-01-01

The quality control requirements for nuclear power plants are done by CNEN and might be followed by the organizations that are responsible for those activities, such as: design, suppliers, construction, fabrication, mounting, installation, commissioning, operation, maintenance, modification and decommissioning. The Promon's experience for using a quality control program in the structural design of Angra 2 and 3, and the verification system adopted, are presented. (E.G.) [pt
Using Smart Meters Data for Energy Management Operations and Power Quality Monitoring in a Microgrid

DEFF Research Database (Denmark)

Palacios-Garcia, Emilio J.; Diaz, Enrique Rodriguez; Anvari-Moghaddam, Amjad

2017-01-01

purposes, integrating HAN/BAN communications, alarms and power quality indicators in some cases. All those characteristics make this widely spread equipment a free, accurate and flexible source of information that can replace expensive and dedicated devices. Therefore, this paper presents the integration...... of a commercial advanced metering infrastructure (AMI) in the context of a smart building with an energy management system (EMS). Furthermore, power quality monitoring based on this AMI is explained. All the details regarding the implementation in a laboratory scale application, as well as the obtained results...
Heterogeneity and subjectivity in binary-state opinion formation systems

International Nuclear Information System (INIS)

Guo, Long; Luo, Zhongjie; Zhu, Yueying

2013-01-01

In society, there is heterogeneous interaction and randomness in human decision making. In order to unfold the roles and the competition of the two factors mentioned above in opinion formation, we propose a toy model, which follows a majority rule with a Fermi function, on scale-free networks with degree exponent γ. The heterogeneous interaction is related to the connectivity of a person with the interactive parameter β, and the randomness of human decision making is quantified by the interaction noise T. We find that a system with heterogeneity of network topology and interaction shows robustness perturbed by the interaction noise T according to the theoretical analysis and numerical simulation. Then, when T → 0, the homogeneous interaction (β ≃ 0) has a powerful implication for the emergence of a consensus state. Furthermore, the emergence of the two extreme values shows the competition of the heterogeneity of interaction and the subjectivity of human decision making in opinion formation. Our present work provides some perspective on and tools for understanding the diversity of opinion in our society. (paper)
Does heterogeneity of pimonidazole labelling correspond to the heterogeneity of radiation-response of FaDu human squamous cell carcinoma?

International Nuclear Information System (INIS)

Yaromina, Ala; Hoelscher, Tobias; Eicheler, Wolfgang; Rosner, Andrea; Krause, Mechthild; Hessel, Franziska; Petersen, Cordula; Thames, Howard D.; Baumann, Michael; Zips, Daniel

2005-01-01

fraction in FaDu tumours corresponds well to the radiobiological hypoxic fraction, the variability of pHF in FaDu tumours was not sufficient to explain the heterogeneity of radiation response in the same tumour line. Information on at least one additional parameter is expected to substantially enhance the predictive power of histological markers of tumour hypoxia
Improving the Power Quality in Tehran Metro Line-Two Using the Ant Colony Algorithm

Directory of Open Access Journals (Sweden)

H. Ehteshami

2017-12-01

Full Text Available This research aims to survey the improvement of power quality in Tehran metro line 2 using the ant colony algorithm and to investigate all the factors affecting the achievement of this goal. In order to put Tehran on the road of sustainable development, finding a solution for dealing with air pollution is essential. The use of public transportation, especially metro, is one of the ways to achieve this goal. Since the highest share of pollutants in Tehran belongs to cars and mobile sources, relative statistical indicators are estimated through assuming the effect of metro lines development and subsequently reduction of traffic on power quality index.
Fuel quality and its effect on the design of power boilers in the USA

Energy Technology Data Exchange (ETDEWEB)

Kotler, V.R.

1984-05-01

Statistical data, taken from Power, Proceedings of the American Power Conference and others, on developments since the 1950s in boiler design caused by the increasing use of lower quality fuel (subbituminous and lignite coals) are presented. The effect of pollution regulations in the USA on boiler design is discussed. The results of a 16 year study by the TVA on the decrease in coal quality fired in its boilers and its effect on boiler efficiency are presented. Methods of transport are surveyed. Descriptions and characteristics of several modern boilers designed by Babcock and Wilcox, Combustion Engineering, Foster-Wheeler and Riley Stoker are given. 13 references.
New Heterogeneous Clustering Protocol for Prolonging Wireless Sensor Networks Lifetime

Directory of Open Access Journals (Sweden)

Md. Golam Rashed

2014-06-01

Full Text Available Clustering in wireless sensor networks is one of the crucial methods for increasing of network lifetime. The network characteristics of existing classical clustering protocols for wireless sensor network are homogeneous. Clustering protocols fail to maintain the stability of the system, especially when nodes are heterogeneous. We have seen that the behavior of Heterogeneous-Hierarchical Energy Aware Routing Protocol (H-HEARP becomes very unstable once the first node dies, especially in the presence of node heterogeneity. In this paper we assume a new clustering protocol whose network characteristics is heterogeneous for prolonging of network lifetime. The computer simulation results demonstrate that the proposed clustering algorithm outperforms than other clustering algorithms in terms of the time interval before the death of the first node (we refer to as stability period. The simulation results also show the high performance of the proposed clustering algorithm for higher values of extra energy brought by more powerful nodes.
The N-Pact Factor: Evaluating the Quality of Empirical Journals with Respect to Sample Size and Statistical Power

Science.gov (United States)

Fraley, R. Chris; Vazire, Simine

2014-01-01

The authors evaluate the quality of research reported in major journals in social-personality psychology by ranking those journals with respect to their N-pact Factors (NF)—the statistical power of the empirical studies they publish to detect typical effect sizes. Power is a particularly important attribute for evaluating research quality because, relative to studies that have low power, studies that have high power are more likely to (a) to provide accurate estimates of effects, (b) to produce literatures with low false positive rates, and (c) to lead to replicable findings. The authors show that the average sample size in social-personality research is 104 and that the power to detect the typical effect size in the field is approximately 50%. Moreover, they show that there is considerable variation among journals in sample sizes and power of the studies they publish, with some journals consistently publishing higher power studies than others. The authors hope that these rankings will be of use to authors who are choosing where to submit their best work, provide hiring and promotion committees with a superior way of quantifying journal quality, and encourage competition among journals to improve their NF rankings. PMID:25296159
Painting for nuclear power stations and machinery and equipments according to quality assurance program of ANSI

International Nuclear Information System (INIS)

Fukuda, Shinzo; Tsuchiya, Yukikazu.

1979-01-01

Recently, painting for nuclear power stations is carried out with the paints made domestically, and these paints are tested and judged generally according to the items of performance evaluation decided by the American National Standard Institute. In Japan, there is no standard regarding the paints for nuclear power stations. Painting is very important process, and it is appropriate to introduce quality assurance program into it. In this paper, the contents of ANSI standard concerning the paints and painting for nuclear power stations are explained, and the outline of the painting of heat exchangers carried out in accordance with the quality assurance program in the Tamano Shipyard, Mitsui Shipbuilding and Engineering Co., Ltd., is described. The test items for evaluating the general performance of the paints, the testing method for evaluating the endurance at the time of an accident, the quality assurance for the paints used for the facilities handling radiation and others are explained. Various problems arise when the quality assurance program of ANSI is applied actually to painting. It is difficult to judge the quality of paints and painting with numerical values, and much efforts were required to establish the quality assurance organization. The conditions for painting, the handling of many documents, the measures to unsatisfactory painting and so on caused much difficulties. (Kako, I.)
The Economic Value of Changes in Water Quality

DEFF Research Database (Denmark)

Jensen, Anne Kejser

Water quality is from both a European and Danish perspective challenged by private use of the resource. The public good characteristics of the resource require that regulation should internalize the non-market values of water quality, in order to reach an optimal level from a welfare economic...... perspective. Valuation using stated preference techniques to value changes in ecosystem services has been widely used to estimate values of water quality. However, heterogeneity in values exists across different groups in the population. The objective of this PhD-thesis is to explore two different kinds...... of preference heterogeneity, when valuing changes in water quality. The PhD thesis consists of four papers all related to heterogeneity in the public preferences for water quality improvements. Papers referred to as 1, 2 and 3 are based on a discrete choice experiment (DCE) on water quality improvements...
Heterogeneous oxidation of SO2 in the radiation chemical purification of exhaust gases of thermoelectric power plants from oxides of nitrogen and sulfur

International Nuclear Information System (INIS)

Gerasimova, T.S.; Gerasimov, G.Ya.; Tokmacheva, I.P.

1992-01-01

Questions associated with numerical modeling of the heterogeneous oxidation of SO 2 in exhaust gases of thermoelectric power plants, induced by irradiation of the gas with a flux of fast electrons, are discussed. In constructing a mathematical model of the process it is considered that a phase equilibrium exists between the gas and the aerosol drops formed in the gas under the radiation influence, and the rate of the process is determined by the rate of liquid-phase oxidation of SO 2 by nitrogen dioxide in dissolved form. 7 refs., 4 figs
Poverty targeting with heterogeneous endowments: a micro-simulation analysis of a less-favourded Ethiopian village

NARCIS (Netherlands)

Kuiper, M.H.; Ruben, R.

2005-01-01

Spatially-targeted programs for poverty reduction in less-favoured areas are typically constrained by a large heterogeneity amongst households in terms of the quantity and quality of available resources. The objective of this paper is to explore in a stylized manner the role of heterogeneous
Muscle power is an independent determinant of pain and quality of life in knee osteoarthritis

Science.gov (United States)

OBJECTIVE: This study examined the relationships between leg muscle strength, power, and perceived disease severity in subjects with knee osteoarthritis (OA) in order to determine whether dynamic leg extensor muscle power would be associated with pain and quality of life in knee OA. METHODS: Baseli...
A Preliminary Design Study of Ultra-Long-Life SFR Cores having Heterogeneous Fuel Assemblies

Energy Technology Data Exchange (ETDEWEB)

Jung, GeonHee; You, WuSeung; Hong, Ser Gi [Kyung Hee University, Yongin (Korea, Republic of)

2016-10-15

The PWR and CANDU reactors have provided electricity for several decades in our country but they have produced lots of spent fuels and so the safe and efficient disposal of these spent fuels is one of the main issues in nuclear industry. This type ultra-long-life cores are quite efficient in terms of the amount of spent fuel generation per electricity production and they can be used as an interim storage for PWR or CANDU spent fuel over several tens of years if they use the PWR or CANDU spent fuel as the initial fuel. Typically, the previous works have considered radially homogeneous fuel assemblies in which only blanket or driver fuel rods are employed and they considered axially or radially heterogeneous core configurations with the radially homogeneous fuel assemblies. These core configurations result in the propagation of the power distribution which can lead to the significant temperature changes for each fuel assembly over the time. In this work, the radially heterogeneous fuel assemblies are employed in new ultra-long-life SFR (Sodium-cooled Fast Reactor) cores to minimize the propagation of power distribution by allowing the power propagation in the fuel assemblies. In this work, new small ultra-long life SFR cores were designed with heterogeneous fuel assemblies having both blanket and driver fuel rods to minimize the propagation of power distribution over the core by allowing power propagation from driver rods to blanket rods in fuel assemblies. In particular, high fidelity depletion calculation coupled with heterogeneous Monte Carlo neutron transport calculation was performed to assess the neutronic feasibility of the ultralong life cores. The results of the analysis showed that the candidate core has the cycle length of 77 EFPYs, a small burnup reactivity swing of 1590 pcm and acceptably small SVRs both at BOC and EOC.
Requirements for auditing of quality assurance programs for nuclear power plants

International Nuclear Information System (INIS)

Anon.

1979-01-01

Requirements and guidance are provided for establishing and implementing a system of internal and external audits of quality assurance programs for nuclear power plants, including the preparation, performance, reporting and follow-up of audits by both the auditing and the audited organizations. This standard is to be used in conjunction with ANSI N45.2
Neural Network based Control of SG based Standalone Generating System with Energy Storage for Power Quality Enhancement

Science.gov (United States)

Nayar, Priya; Singh, Bhim; Mishra, Sukumar

2017-08-01

An artificial intelligence based control algorithm is used in solving power quality problems of a diesel engine driven synchronous generator with automatic voltage regulator and governor based standalone system. A voltage source converter integrated with a battery energy storage system is employed to mitigate the power quality problems. An adaptive neural network based signed regressor control algorithm is used for the estimation of the fundamental component of load currents for control of a standalone system with load leveling as an integral feature. The developed model of the system performs accurately under varying load conditions and provides good dynamic response to the step changes in loads. The real time performance is achieved using MATLAB along with simulink/simpower system toolboxes and results adhere to an IEEE-519 standard for power quality enhancement.
76 FR 45741 - Approval and Promulgation of Air Quality Implementation Plans; Pennsylvania; Diesel-Powered Motor...

Science.gov (United States)

2011-08-01

... Promulgation of Air Quality Implementation Plans; Pennsylvania; Diesel-Powered Motor Vehicle Idling Act AGENCY... the Commonwealth's Diesel-Powered Motor Vehicle Idling Act (Act 124 of 2008, or simply Act 124) into... allowable time that heavy-duty, commercial highway diesel vehicles of over 10,000 pounds gross vehicle...

Mass Spectrometry Imaging for the Investigation of Intratumor Heterogeneity.

Science.gov (United States)

Balluff, B; Hanselmann, M; Heeren, R M A

2017-01-01

One of the big clinical challenges in the treatment of cancer is the different behavior of cancer patients under guideline therapy. An important determinant for this phenomenon has been identified as inter- and intratumor heterogeneity. While intertumor heterogeneity refers to the differences in cancer characteristics between patients, intratumor heterogeneity refers to the clonal and nongenetic molecular diversity within a patient. The deciphering of intratumor heterogeneity is recognized as key to the development of novel therapeutics or treatment regimens. The investigation of intratumor heterogeneity is challenging since it requires an untargeted molecular analysis technique that accounts for the spatial and temporal dynamics of the tumor. So far, next-generation sequencing has contributed most to the understanding of clonal evolution within a cancer patient. However, it falls short in accounting for the spatial dimension. Mass spectrometry imaging (MSI) is a powerful tool for the untargeted but spatially resolved molecular analysis of biological tissues such as solid tumors. As it provides multidimensional datasets by the parallel acquisition of hundreds of mass channels, multivariate data analysis methods can be applied for the automated annotation of tissues. Moreover, it integrates the histology of the sample, which enables studying the molecular information in a histopathological context. This chapter will illustrate how MSI in combination with statistical methods and histology has been used for the description and discovery of intratumor heterogeneity in different cancers. This will give evidence that MSI constitutes a unique tool for the investigation of intratumor heterogeneity, and could hence become a key technology in cancer research. © 2017 Elsevier Inc. All rights reserved.
Magnetic field emission comparison at different quality factors with series-series compensation network for inductive power transfer to vehicles

DEFF Research Database (Denmark)

Batra, Tushar; Schaltz, Erik

2014-01-01

Inductive power transfer is non-contact transfer of energy by means of magnetic fields. A higher secondary side quality factor at fixed input current ensures a linear increase in power transfer across the air gap. But also at the same time magnetic emissions to the surroundings increase. First...... of all in this paper an analytic expression for comparing the magnetic emissions at different quality factors is introduced. It is shown with help of simulations on Comsol that emissions have a lower increase as compared to linear increase in the power transferred with the quality factor as suggested...
Power quality improvement by using multi-pulse AC-DC converters for DC drives: Modeling, simulation and its digital implementation

Directory of Open Access Journals (Sweden)

Mohd Tariq

2014-12-01

Full Text Available The paper presents the modeling, simulation and digital implementation of power quality improvement of DC drives by using multi pulse AC–DC converter. As it is a well-known fact that power quality determines the fitness of electrical power to consumer devices, hence an effort has been made to improve power quality in this work. Simulation and digital implementation with the help of MATLAB/Simulink has been done and results obtained are discussed in detail to verify the theoretical results. The multipulse converter was connected with DC drives and was run at no load condition to find out the transient and steady state performances. FFT analysis has been performed and Total Harmonic Distortion (THD results obtained at different pulses are shown here.
A Digital Power Quality Monitoring Equipment Designed for Digital Substation

Science.gov (United States)

Li, Wei; Wang, Xin; Geng, Jiewen

2018-01-01

Taking into account both current status and development trend of digital substation, this paper proposed a design of a new multi-channelled digital power quality monitoring equipment with high compatibility. The overall functional structure, hardware architecture, software architecture, interface architecture and some key techniques such as IEC 61850 modelling of transient event and harmonic measurement method under the condition of non-synchronous sampling are described in this paper.
Analysis and experimental verification of a control scheme for unified power quality conditioner

Energy Technology Data Exchange (ETDEWEB)

Peng Cheng Zhu; Xun Li; Yong Kang; Jian Chen [Huazhong Univ. of Science and Techmnology, Wuhan (China). Dept. of Electrical Engineering

2005-07-01

Improving power quality for sensitive load by a Unified Power Quality Conditioner (UPQC) in a distributed generation system is presented in this paper. The power balance of a UPQC, consisting of back-to-back connected series and shunt Active Filters (AF), is analysed. Based on the analysis a novel control scheme is established in a 2-phase Synchronous Rotating d-q Frame (SRF). In this control scheme, the series AF is controlled as a current source and makes the input current sinusoidal, while the shunt AF is controlled as a voltage source and keeps the load voltage in the normal value. With the proposed control strategy, the UPQC is capable of compensating not only harmonic and reactive currents of the load but also grid voltage distortion. There is no harmonic interference between harmonic-producing loads and harmonic-sensitive loads, which are connected on the common bus. The performance of a UPQC with the proposed control scheme under nonlinear load and grid voltage distortion is investigated with simulation as well as experimental works. (Author)
Power quality issues into a Danish low-voltage grid with electric vehicles

DEFF Research Database (Denmark)

Marra, Francesco; Jensen, Morten M.; Garcia-Valle, Rodrigo

2011-01-01

An increased interest on electric vehicles (EVs) and plug-in hybrid electric vehicles (PHEVs) is dealing with their introduction into low voltage (LV) distribution grids. Lately, analysis on power quality issues has received attention when considering EVs as additional load. The charging of EVs...
Power law analysis of the human microbiome.

Science.gov (United States)

Ma, Zhanshan Sam

2015-11-01

Taylor's (1961, Nature, 189:732) power law, a power function (V = am(b) ) describing the scaling relationship between the mean and variance of population abundances of organisms, has been found to govern the population abundance distributions of single species in both space and time in macroecology. It is regarded as one of few generalities in ecology, and its parameter b has been widely applied to characterize spatial aggregation (i.e. heterogeneity) and temporal stability of single-species populations. Here, we test its applicability to bacterial populations in the human microbiome using extensive data sets generated by the US-NIH Human Microbiome Project (HMP). We further propose extending Taylor's power law from the population to the community level, and accordingly introduce four types of power-law extensions (PLEs): type I PLE for community spatial aggregation (heterogeneity), type II PLE for community temporal aggregation (stability), type III PLE for mixed-species population spatial aggregation (heterogeneity) and type IV PLE for mixed-species population temporal aggregation (stability). Our results show that fittings to the four PLEs with HMP data were statistically extremely significant and their parameters are ecologically sound, hence confirming the validity of the power law at both the population and community levels. These findings not only provide a powerful tool to characterize the aggregations of population and community in both time and space, offering important insights into community heterogeneity in space and/or stability in time, but also underscore the three general properties of power laws (scale invariance, no average and universality) and their specific manifestations in our four PLEs. © 2015 John Wiley & Sons Ltd.
Multihopping Multilevel Clustering Heterogeneity-Sensitive Optimized Routing Protocol for Wireless Sensor Networks

Directory of Open Access Journals (Sweden)

Muhammad Aslam

2017-01-01

Full Text Available Effective utilization of energy resources in Wireless Sensor Networks (WSNs has become challenging under uncertain distributed cluster-formation and single-hop intercluster communication capabilities. So, sensor nodes are forced to operate at expensive full rate transmission power level continuously during whole network operation. These challenging network environments experience unwanted phenomena of drastic energy consumption and packet drop. In this paper, we propose an adaptive immune Multihopping Multilevel Clustering (MHMLC protocol that executes a Hybrid Clustering Algorithm (HCA to perform optimal centralized selection of Cluster-Heads (CHs within radius of centrally located Base Station (BS and distributed CHs selection in the rest of network area. HCA of MHMLC also produces optimal intermediate CHs for intercluster multihop communications that develop heterogeneity-aware economical links. This hybrid cluster-formation facilitates the sensors to function at short range transmission power level that enhances link quality and avoids packet drop. The simulation environments produce fair comparison among proposed MHMLC and existing state-of-the-art routing protocols. Experimental results give significant evidence of better performance of the proposed model in terms of network lifetime, stability period, and data delivery ratio.
Collision Resolution Scheme with Offset for Improved Performance of Heterogeneous WLAN

Science.gov (United States)

Upadhyay, Raksha; Vyavahare, Prakash D.; Tokekar, Sanjiv

2016-03-01

CSMA/CA based DCF of 802.11 MAC layer employs best effort delivery model, in which all stations compete for channel access with same priority. Heterogeneous conditions result in unfairness among stations and degradation in throughput, therefore, providing different priorities to different applications for required quality of service in heterogeneous networks is challenging task. This paper proposes a collision resolution scheme with a novel concept of introducing offset, which is suitable for heterogeneous networks. Selection of random value by a station for its contention with offset results in reduced probability of collision. Expression for the optimum value of the offset is also derived. Results show that proposed scheme, when applied to heterogeneous networks, has improved throughput and fairness than conventional scheme. Results show that proposed scheme also exhibits higher throughput and fairness with reduced delay in homogeneous networks.
A feasibility study on HTS SMES applications for power quality enhancement through both software simulations and hardware-based experiments

Energy Technology Data Exchange (ETDEWEB)

Kim, A.R.; Kim, J.G.; Kim, S. [Changwon National University, 9 Sarim-Dong, Changwon 641-773 (Korea, Republic of); Park, M., E-mail: paku@changwon.ac.kr [Changwon National University, 9 Sarim-Dong, Changwon 641-773 (Korea, Republic of); Yu, I.K. [Changwon National University, 9 Sarim-Dong, Changwon 641-773 (Korea, Republic of); Seong, K.C. [Superconducting Device and Cryogenics Group, Korea Electrotechnology Research Institute, Changwon 641-120 (Korea, Republic of); Watanabe, K. [HFLSM, Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan)

2011-11-15

SMES system was simulated to improve the power quality. The utility has one wind power generator and wind speed is continuously changed. Utility frequency was fluctuated due to wind speed variation. We made 10 kJ toroid-type HTS SMES for stabilization of utility frequency. We can monitor the operational characteristics of HTS SMES for power application. Superconducting magnetic energy storage (SMES) which promises the efficiency of more than 95% and fast response becomes a competitive energy storage device. Because of its advantages, SMES can provide benefit as a power quality enhancement device to an utility especially in connection with renewable energy sources. In this paper, a software simulation and an experiment aiming for power quality enhancement are reported. The utility was referred to Ulleung Island in Korea which had one wind power generation system. The simulation was performed using power system computer aided design/electromagnetic transient including DC (PSCAD/EMTDC) and power-hardware-in-the-loop simulation (PHILS) was implemented to monitor the operational characteristics of SMES when it was connected to utility. This study provides a highly reliable simulation results, and the feasibility of a SMES application is discussed.
A feasibility study on HTS SMES applications for power quality enhancement through both software simulations and hardware-based experiments

International Nuclear Information System (INIS)

Kim, A.R.; Kim, J.G.; Kim, S.; Park, M.; Yu, I.K.; Seong, K.C.; Watanabe, K.

2011-01-01

SMES system was simulated to improve the power quality. The utility has one wind power generator and wind speed is continuously changed. Utility frequency was fluctuated due to wind speed variation. We made 10 kJ toroid-type HTS SMES for stabilization of utility frequency. We can monitor the operational characteristics of HTS SMES for power application. Superconducting magnetic energy storage (SMES) which promises the efficiency of more than 95% and fast response becomes a competitive energy storage device. Because of its advantages, SMES can provide benefit as a power quality enhancement device to an utility especially in connection with renewable energy sources. In this paper, a software simulation and an experiment aiming for power quality enhancement are reported. The utility was referred to Ulleung Island in Korea which had one wind power generation system. The simulation was performed using power system computer aided design/electromagnetic transient including DC (PSCAD/EMTDC) and power-hardware-in-the-loop simulation (PHILS) was implemented to monitor the operational characteristics of SMES when it was connected to utility. This study provides a highly reliable simulation results, and the feasibility of a SMES application is discussed.
FLC based adjustable speed drives for power quality enhancement

Directory of Open Access Journals (Sweden)

Sukumar Darly

2010-01-01

Full Text Available This study describes a new approach based on fuzzy algorithm to suppress the current harmonic contents in the output of an inverter. Inverter system using fuzzy controllers provide ride-through capability during voltage sags, reduces harmonics, improves power factor and high reliability, less electromagnetic interference noise, low common mode noise and extends output voltage range. A feasible test is implemented by building a model of three-phase impedance source inverter, which is designed and controlled on the basis of proposed considerations. It is verified from the practical point of view that these new approaches are more effective and acceptable to minimize the harmonic distortion and improves the quality of power. Due to the complex algorithm, their realization often calls for a compromise between cost and performance. The proposed optimizing strategies may be applied in variable-frequency dc-ac inverters, UPSs, and ac drives.
Integrating mean and variance heterogeneities to identify differentially expressed genes.

Science.gov (United States)

Ouyang, Weiwei; An, Qiang; Zhao, Jinying; Qin, Huaizhen

2016-12-06

In functional genomics studies, tests on mean heterogeneity have been widely employed to identify differentially expressed genes with distinct mean expression levels under different experimental conditions. Variance heterogeneity (aka, the difference between condition-specific variances) of gene expression levels is simply neglected or calibrated for as an impediment. The mean heterogeneity in the expression level of a gene reflects one aspect of its distribution alteration; and variance heterogeneity induced by condition change may reflect another aspect. Change in condition may alter both mean and some higher-order characteristics of the distributions of expression levels of susceptible genes. In this report, we put forth a conception of mean-variance differentially expressed (MVDE) genes, whose expression means and variances are sensitive to the change in experimental condition. We mathematically proved the null independence of existent mean heterogeneity tests and variance heterogeneity tests. Based on the independence, we proposed an integrative mean-variance test (IMVT) to combine gene-wise mean heterogeneity and variance heterogeneity induced by condition change. The IMVT outperformed its competitors under comprehensive simulations of normality and Laplace settings. For moderate samples, the IMVT well controlled type I error rates, and so did existent mean heterogeneity test (i.e., the Welch t test (WT), the moderated Welch t test (MWT)) and the procedure of separate tests on mean and variance heterogeneities (SMVT), but the likelihood ratio test (LRT) severely inflated type I error rates. In presence of variance heterogeneity, the IMVT appeared noticeably more powerful than all the valid mean heterogeneity tests. Application to the gene profiles of peripheral circulating B raised solid evidence of informative variance heterogeneity. After adjusting for background data structure, the IMVT replicated previous discoveries and identified novel experiment
Effect of Hartha and Najibia power plants on water quality indices of Shatt Al-Arab River, south of Iraq

Science.gov (United States)

Al-Aboodi, Ali H.; Abbas, Sarmad A.; Ibrahim, Husham T.

2018-05-01

The main object of this research is to assess the water quality of Shatt Al-Arab River and its suitability for various purposes near power plants (Hartha and Najibia) through physical and chemical analysis [temperature, pH, EC, Cl-, Na+, K+, Ca+2, Mg+2, HCO3 -, NO3 -, SO 4 -2 , Fe+, total alkalinity, total hardness, biological oxygen demand (BOD5), NH4 +, and NO2 -] using water quality index (WQI), organic pollution index (OPI), sodium adsorption ratio (SAR), and percentage of sodium ion (Na%) during the dry season (August, 2016) and the wet season (January, 2017). WQI of Shatt Al-Arab falls under very poor quality during summer season, while it ranges from very poor quality to unsuitable for drinking purposes during winter season. There is a clear effect of power plants on water quality. Hartha and Najibia power plants contribute to the deterioration of water quality by increasing the percentage ratio of WQI near these plants by 13.22 and 9.69%, respectively, compared to the north sites of these plants during summer season. The percentage ratios of increased WQI near Hartha and Najibia power plants compared to the north sites of these plants are 17.93 and 15.92%, respectively, during winter season. Water quality of Shatt Al-Arab falls under a high level of organic pollution during the summer and winter seasons. There is a slight effect by the power plants on the OPI. Hartha and Najibia power plants contributed to the change of the OPI by 10% compared to the north site of Hartha power plant. According to the comparison between the SAR values which represent the suitability of water for serve irrigation purposes and SAR values of Shatt Al-Arab, all sites lie in the first class (excellent). According to Na+%, the type of surface water in the studied area lies in good class during winter season and permissible class during summer season.
"Power quality system," a new system of quality management for globalization: towards innovation and competitive advantages.

Science.gov (United States)

Abdul-Rahman, H; Berawi, M A

Knowledge Management (KM) addresses the critical issues of organizational adoption, survival and competence in the face of an increasingly changing environment. KM embodies organizational processes that seek a synergistic combination of the data and information processing capabilities of information and communication technologies (ICT), and the creative and innovative capacity of human beings to improve ICT In that role, knowledge management will improve quality management and avoid or minimize losses and weakness that usually come from poor performance as well as increase the competitive level of the company and its ability to survive in the global marketplace. To achieve quality, all parties including the clients, company consultants, contractors, entrepreneurs, suppliers, and the governing bodies (i.e., all involved stake-holders) need to collaborate and commit to achieving quality. The design based organizations in major business and construction companies have to be quality driven to support healthy growth in today's competitive market. In the march towards vision 2020 and globalization (i.e., the one world community) of many companies, their design based organizations need to have superior quality management and knowledge management to anticipate changes. The implementation of a quality system such as the ISO 9000 Standards, Total Quality Management, or Quality Function Deployment (QFD) focuses the company's resources towards achieving faster and better results in the global market with less cost. To anticipate the needs of the marketplace and clients as the world and technology change, a new system, which we call Power Quality System (PQS), has been designed. PQS is a combination of information and communication technologies (ICT) and the creative and innovative capacity of human beings to meet the challenges of the new world business and to develop high quality products.
Designing Domain-Specific Heterogeneous Architectures from Dataflow Programs

Directory of Open Access Journals (Sweden)

Süleyman Savas

2018-04-01

Full Text Available The last ten years have seen performance and power requirements pushing computer architectures using only a single core towards so-called manycore systems with hundreds of cores on a single chip. To further increase performance and energy efficiency, we are now seeing the development of heterogeneous architectures with specialized and accelerated cores. However, designing these heterogeneous systems is a challenging task due to their inherent complexity. We proposed an approach for designing domain-specific heterogeneous architectures based on instruction augmentation through the integration of hardware accelerators into simple cores. These hardware accelerators were determined based on their common use among applications within a certain domain.The objective was to generate heterogeneous architectures by integrating many of these accelerated cores and connecting them with a network-on-chip. The proposed approach aimed to ease the design of heterogeneous manycore architectures—and, consequently, exploration of the design space—by automating the design steps. To evaluate our approach, we enhanced our software tool chain with a tool that can generate accelerated cores from dataflow programs. This new tool chain was evaluated with the aid of two use cases: radar signal processing and mobile baseband processing. We could achieve an approximately 4 × improvement in performance, while executing complete applications on the augmented cores with a small impact (2.5–13% on area usage. The generated accelerators are competitive, achieving more than 90% of the performance of hand-written implementations.
The Power of Heterogeneity: Parameter Relationships from Distributions

Science.gov (United States)

Röding, Magnus; Bradley, Siobhan J.; Williamson, Nathan H.; Dewi, Melissa R.; Nann, Thomas; Nydén, Magnus

2016-01-01

Complex scientific data is becoming the norm, many disciplines are growing immensely data-rich, and higher-dimensional measurements are performed to resolve complex relationships between parameters. Inherently multi-dimensional measurements can directly provide information on both the distributions of individual parameters and the relationships between them, such as in nuclear magnetic resonance and optical spectroscopy. However, when data originates from different measurements and comes in different forms, resolving parameter relationships is a matter of data analysis rather than experiment. We present a method for resolving relationships between parameters that are distributed individually and also correlated. In two case studies, we model the relationships between diameter and luminescence properties of quantum dots and the relationship between molecular weight and diffusion coefficient for polymers. Although it is expected that resolving complicated correlated relationships require inherently multi-dimensional measurements, our method constitutes a useful contribution to the modelling of quantitative relationships between correlated parameters and measurements. We emphasise the general applicability of the method in fields where heterogeneity and complex distributions of parameters are obstacles to scientific insight. PMID:27182701
Key methods for sustaining quality engineering data in nuclear power plants

Energy Technology Data Exchange (ETDEWEB)

Cook, A [Canatom Ltd., Montreal, PQ (Canada)

1996-12-31

This paper discusses key methods for sustaining quality engineering data, the fundamental principles that these methods are based on, and the methods for supporting the performance of nuclear power plants by the provision of quality engineering data at all times. The concept of an `engineering data foundation`, and a Configuration Management data model are developed. The concepts and methods for managing the integrity of engineering data across many different databases and document systems are developed, including the key concepts of data-positions and data-values, Master Data and Copy Data, and the concept of a `partnership between people and technology`. (author). 7 refs., 1 tab., 2 figs.
Key methods for sustaining quality engineering data in nuclear power plants

International Nuclear Information System (INIS)

Cook, A.

1995-01-01

This paper discusses key methods for sustaining quality engineering data, the fundamental principles that these methods are based on, and the methods for supporting the performance of nuclear power plants by the provision of quality engineering data at all times. The concept of an 'engineering data foundation', and a Configuration Management data model are developed. The concepts and methods for managing the integrity of engineering data across many different databases and document systems are developed, including the key concepts of data-positions and data-values, Master Data and Copy Data, and the concept of a 'partnership between people and technology'. (author). 7 refs., 1 tab., 2 figs
Quality assurance of Daya Bay Nuclear Power Plant in operations phase

International Nuclear Information System (INIS)

Cai Kangyuan

2000-01-01

The author introduces the responsibilities and functions of QA Department in Daya Bay Nuclear Power Station. It describes how QAD verifies the effectiveness of implementation of QA Program through its main QA activities: QA audits and QA surveillances. It also describes the quality deficiency classification, follow up and verification system, and its reporting system. It explains how QAD provides its supports and services to functional branches at the same time when it maintains its independence. At last it briefly introduces how QAD pushes Management Self Assessment activities in the Plant scope when performance based quality assurance is implemented and how it exercises real time QA monitoring activity during outage

Multi-Functional Distributed Generation Unit for Power Quality Enhancement

DEFF Research Database (Denmark)

Zeng, Zheng; Yang, Huan; Guerrero, Josep M.

2015-01-01

A multi-functional distributed generation unit (MFDGU) and its control strategy are proposed in this paper for the purpose of enhancing power quality in low-voltage networks. By using the 3H-bridge converter structure, an MFDGU can be applied in 3-phase 4-wire low-voltage distribution networks...... reference of the MFDGU, which can be easily implemented in three-phase networks. A 15kVA prototype consisting of three full bridge converters has been built and tested. Experimental results show the feasibility of the proposed topology and control strategy....
Neutronic of heterogenous gas cooled reactors

International Nuclear Information System (INIS)

Maturana, Roberto Hernan

2008-01-01

At present, one of the main technical features of the advanced gas cooled reactor under development is its fuel element concept, which implies a neutronic homogeneous design, thus requiring higher enrichment compared with present commercial nuclear power plants.In this work a neutronic heterogeneous gas cooled reactor design is analyzed by studying the neutronic design of the Advanced Gas cooled Reactor (AGR), a low enrichment, gas cooled and graphite moderated nuclear power plant.A search of merit figures (some neutronic parameter, characteristic dimension, or a mixture of both) which are important and have been optimized during the reactor design stage is been done, to aim to comprise how a gas heterogeneous reactor is been design, given that semi-infinity arrangement criteria of rods in LWRs and clusters in HWRs can t be applied for a solid moderator and a gas refrigerator.The WIMS code for neutronic cell calculations is been utilized to model the AGR fuel cell and to calculate neutronic parameters such as the multiplication factor and the pick factor, as function of the fuel burnup.Also calculation is been done for various nucleus characteristic dimensions values (fuel pin radius, fuel channel pitch) and neutronic parameters (such as fuel enrichment), around the design established parameters values.A fuel cycle cost analysis is carried out according to the reactor in study, and the enrichment effect over it is been studied.Finally, a thermal stability analysis is been done, in subcritical condition and at power level, to study this reactor characteristic reactivity coefficients.Present results shows (considering the approximation used) a first set of neutronic design figures of merit consistent with the AGR design. [es
Power, uncertainty, self-transcendence, and quality of life in breast cancer survivors.

Science.gov (United States)

Farren, Arlene T

2010-01-01

The purpose of the study was to examine the relations among power, uncertainty, self-transcendence, and quality of life in breast cancer survivors from the perspective of Rogers' science of unitary human beings. A correlational, cross-sectional study with purposive sampling (n = 104) was conducted. The results included statistically significant correlations, explained variance, and mediating relations among the pattern manifestations. The researcher concluded that there are complex and synergistic relations among the cluster of field pattern manifestations that contribute to quality of life in breast cancer survivors. Implications for theory, research, and practice are discussed.
Simulation and study of power quality issues in a fixed speed wind farm substation.

Science.gov (United States)

Magesh, T; Chellamuthu, C

2015-01-01

Power quality issues associated with the fixed speed wind farm substation located at Coimbatore district are investigated as the wind generators are tripping frequently. The investigations are carried out using two power quality analyzers, Fluke 435 and Dranetz PX5.8, with one of them connected at group control breaker of the 110 kV feeder and the other at the selected 0.69 kV generator busbar during the period of maximum power generation. From the analysis of the recorded data it is found that sag, swell, and transients are the major events which are responsible for the tripping of the generators. In the present study, simulation models for wind, turbine, shaft, pitch mechanism, induction generator, and grid are developed using DIgSILENT. Using the turbine characteristics, a two-dimensional lookup table is designed to generate a reference pitch angle necessary to simulate the power curve of the passive stall controlled wind turbine. Various scenarios and their effects on the performance of the wind farm are studied and validated with the recorded data and waveforms. The simulation model will be useful for the designers for planning and development of the wind farm before implementation.
Cascaded analysis of signal and noise propagation through a heterogeneous breast model

International Nuclear Information System (INIS)

Mainprize, James G.; Yaffe, Martin J.

2010-01-01

Purpose: The detectability of lesions in radiographic images can be impaired by patterns caused by the surrounding anatomic structures. The presence of such patterns is often referred to as anatomic noise. Others have previously extended signal and noise propagation theory to include variable background structure as an additional noise term and used in simulations for analysis by human and ideal observers. Here, the analytic forms of the signal and noise transfer are derived to obtain an exact expression for any input random distribution and the ''power law'' filter used to generate the texture of the tissue distribution. Methods: A cascaded analysis of propagation through a heterogeneous model is derived for x-ray projection through simulated heterogeneous backgrounds. This is achieved by considering transmission through the breast as a correlated amplification point process. The analytic forms of the cascaded analysis were compared to monoenergetic Monte Carlo simulations of x-ray propagation through power law structured backgrounds. Results: As expected, it was found that although the quantum noise power component scales linearly with the x-ray signal, the anatomic noise will scale with the square of the x-ray signal. There was a good agreement between results obtained using analytic expressions for the noise power and those from Monte Carlo simulations for different background textures, random input functions, and x-ray fluence. Conclusions: Analytic equations for the signal and noise properties of heterogeneous backgrounds were derived. These may be used in direct analysis or as a tool to validate simulations in evaluating detectability.
Customized power quality service provided by converter interfaced microgrids — Voltage harmonics as a study case

DEFF Research Database (Denmark)

Meng, Lexuan; Chaudhary, Sanjay K.; Guerrero, Josep M.

2017-01-01

Customers may have different power quality requirements, thus, the economic operational strategy can try to provide them with distinctive quality levels as customized service. An optimization based method is proposed in this paper to realize this functionality, offering the possibility...
Impact of extreme load requirements and quality assurance on nuclear power plant costs

International Nuclear Information System (INIS)

Stevenson, J.D.

1993-01-01

Definitive costs, applicable to nuclear power plant concrete structures, as a function of National Regulatory Requirements, standardization, the effect of extreme load design associated with both design basis accidents and extreme external events and quality assurance are difficult to develop since such effects are interrelated and not only differ widely from country to country, project to project but also vary in time. Table 1 shows an estimate of the of the overall plant cost effects of external event extreme load design on nuclear power plant design for the U.S -and selected foreign countries for which experience with LWRs exist- Germany is the most expensive primarily due to a military aircraft crash resistance. However, the German requirement for 4 safeguards trains rather than 2 and the containment design requirement to consider one Steam Generator blowdown concurrent with a RCS blowdown. This presentation will concentrate on the direct current impact extreme load design and quality assurance have on concrete structures, systems and components for nuclear plants. This presentation is considered timely due to the increased interest in the c potential backfit of Eastern European nuclear power stations of the WWER 440 and WWER 1000 types which typically did not consider the extreme loads identified in Table 1 and accident loads in Table 3 and quality assurance in Table 5 in their original design. Concrete structures in particular are highlighted because they typically form the last barrier to radioactive release from the containment and other Safety Related Structures
SDN Based User-Centric Framework for Heterogeneous Wireless Networks

Directory of Open Access Journals (Sweden)

Zhaoming Lu

2016-01-01

Full Text Available Due to the rapid growth of mobile data traffic, more and more basestations and access points (APs have been densely deployed to provide users with ubiquitous network access, which make current wireless network a complex heterogeneous network (HetNet. However, traditional wireless networks are designed with network-centric approaches where different networks have different quality of service (QoS strategies and cannot easily cooperate with each other to serve network users. Massive network infrastructures could not assure users perceived network and service quality, which is an indisputable fact. To address this issue, we design a new framework for heterogeneous wireless networks with the principle of user-centricity, refactoring the network from users’ perspective to suffice their requirements and preferences. Different from network-centric approaches, the proposed framework takes advantage of Software Defined Networking (SDN and virtualization technology, which will bring better perceived services quality for wireless network users. In the proposed user-centric framework, control plane and data plane are decoupled to manage the HetNets in a flexible and coadjutant way, and resource virtualization technology is introduced to abstract physical resources of HetNets into unified virtualized resources. Hence, ubiquitous and undifferentiated network connectivity and QoE (quality of experience driven fine-grained resource management could be achieved for wireless network users.
A weighted U statistic for association analyses considering genetic heterogeneity.

Science.gov (United States)

Wei, Changshuai; Elston, Robert C; Lu, Qing

2016-07-20

Converging evidence suggests that common complex diseases with the same or similar clinical manifestations could have different underlying genetic etiologies. While current research interests have shifted toward uncovering rare variants and structural variations predisposing to human diseases, the impact of heterogeneity in genetic studies of complex diseases has been largely overlooked. Most of the existing statistical methods assume the disease under investigation has a homogeneous genetic effect and could, therefore, have low power if the disease undergoes heterogeneous pathophysiological and etiological processes. In this paper, we propose a heterogeneity-weighted U (HWU) method for association analyses considering genetic heterogeneity. HWU can be applied to various types of phenotypes (e.g., binary and continuous) and is computationally efficient for high-dimensional genetic data. Through simulations, we showed the advantage of HWU when the underlying genetic etiology of a disease was heterogeneous, as well as the robustness of HWU against different model assumptions (e.g., phenotype distributions). Using HWU, we conducted a genome-wide analysis of nicotine dependence from the Study of Addiction: Genetics and Environments dataset. The genome-wide analysis of nearly one million genetic markers took 7h, identifying heterogeneous effects of two new genes (i.e., CYP3A5 and IKBKB) on nicotine dependence. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.
Heterogeneous Catalysis of Polyoxometalate Based Organic–Inorganic Hybrids

Directory of Open Access Journals (Sweden)

Yuanhang Ren

2015-03-01

Full Text Available Organic–inorganic hybrid polyoxometalate (POM compounds are a subset of materials with unique structures and physical/chemical properties. The combination of metal-organic coordination complexes with classical POMs not only provides a powerful way to gain multifarious new compounds but also affords a new method to modify and functionalize POMs. In parallel with the many reports on the synthesis and structure of new hybrid POM compounds, the application of these compounds for heterogeneous catalysis has also attracted considerable attention. The hybrid POM compounds show noteworthy catalytic performance in acid, oxidation, and even in asymmetric catalytic reactions. This review summarizes the design and synthesis of organic–inorganic hybrid POM compounds and particularly highlights their recent progress in heterogeneous catalysis.
Experimental study of the large-scale axially heterogeneous liquid-metal fast breeder reactor at the fast critical assembly: Power distribution measurements and their analyses

International Nuclear Information System (INIS)

Iijima, S.; Obu, M.; Hayase, T.; Ohno, A.; Nemoto, T.; Okajima, S.

1988-01-01

Power distributions of the large-scale axially heterogeneous liquid-metal fast breeder reactor were studied by using the experiment results of fast critical assemblies XI, XII, and XIII and the results of their analyses. The power distributions were examined by the gamma-scanning method and fission rate measurements using /sup 239/Pu and /sup 238/U fission counters and the foil irradiation method. In addition to the measurements in the reference core, the power distributions were measured in the core with a control rod inserted and in a modified core where the shape of the internal blanket was determined by the radial boundary. The calculation was made by using JENDL-2 and the Japan Atomic Energy Research Institute's standard calculation system for fast reactor neutronics. The power flattening trend, caused by the decrease of the fast neutron flux, was observed in the axial and radial power distributions. The effect of the radial boundary shape of the internal blanket on the power distribution was determined in the core. The thickness of the internal blanket was reduced at its radial boundary. The influence of the internal blanket was observed in the power distributions in the core with a control rod inserted. The calculation predicted the neutron spectrum harder in the internal blanket. In the radial distributions of /sup 239/Pu fission rates, the space dependency of the calculated-to-experiment values was found at the active core close to the internal blanket
Spatial heterogeneity study of vegetation coverage at Heihe River Basin

Science.gov (United States)

Wu, Lijuan; Zhong, Bo; Guo, Liyu; Zhao, Xiangwei

2014-11-01

Spatial heterogeneity of the animal-landscape system has three major components: heterogeneity of resource distributions in the physical environment, heterogeneity of plant tissue chemistry, heterogeneity of movement modes by the animal. Furthermore, all three different types of heterogeneity interact each other and can either reinforce or offset one another, thereby affecting system stability and dynamics. In previous studies, the study areas are investigated by field sampling, which costs a large amount of manpower. In addition, uncertain in sampling affects the quality of field data, which leads to unsatisfactory results during the entire study. In this study, remote sensing data is used to guide the sampling for research on heterogeneity of vegetation coverage to avoid errors caused by randomness of field sampling. Semi-variance and fractal dimension analysis are used to analyze the spatial heterogeneity of vegetation coverage at Heihe River Basin. The spherical model with nugget is used to fit the semivariogram of vegetation coverage. Based on the experiment above, it is found, (1)there is a strong correlation between vegetation coverage and distance of vegetation populations within the range of 0-28051.3188m at Heihe River Basin, but the correlation loses suddenly when the distance greater than 28051.3188m. (2)The degree of spatial heterogeneity of vegetation coverage at Heihe River Basin is medium. (3)Spatial distribution variability of vegetation occurs mainly on small scales. (4)The degree of spatial autocorrelation is 72.29% between 25% and 75%, which means that spatial correlation of vegetation coverage at Heihe River Basin is medium high.
Kilowatt isotope power system. Phase II plan. Volume V. Safety, quality assurance and reliability

International Nuclear Information System (INIS)

1978-01-01

The development of a Kilowatt Isotope Power System (KIPS) was begun in 1975 for the purpose of satisfying the power requirements of satellites in the 1980's. The KIPS is a 238 PuO 2 -fueled organic Rankine cycle turbine power system to provide a design output of 500 to 2000 W. Included in this volume are: launch and flight safety considerations; quality assurance techniques and procedures to be followed through system fabrication, assembly and inspection; and the reliability program made up of reliability prediction analysis, failure mode analysis and criticality analysis
Dynamic influences of wind power on the power system

Energy Technology Data Exchange (ETDEWEB)

Rosas, Pedro

2003-03-01

The thesis first presents the basics influences of wind power on the power system stability and quality by pointing out the main power quality issues of wind power in a small-scale case and following, the expected large-scale problems are introduced. Secondly, a dynamic wind turbine model that supports power quality assessment of wind turbines is presented. Thirdly, an aggregate wind farm model that support power quality and stability analysis from large wind farms is presented. The aggregate wind farm model includes the smoothing of the relative power fluctuation from a wind farm compared to a single wind turbine. Finally, applications of the aggregate wind farm model to the power systems are presented. The power quality and stability characteristics influenced by large-scale wind power are illustrated with three cases. In this thesis, special emphasis has been given to appropriate models to represent the wind acting on wind farms. The wind speed model to a single wind turbine includes turbulence and tower shadow effects from the wind and the rotational sampling turbulence due to the rotation of the blades. In a park scale, the wind speed model to the wind farm includes the spatial coherence between different wind turbines. Here the wind speed model is applied to a constant rotational speed wind turbine/farm, but the model is suitable to variable speed wind turbine/farm as well. The cases presented here illustrate the influences of the wind power on the power system quality and stability. The flicker and frequency deviations are the main power quality parameters presented. The power system stability concentrates on the voltage stability and on the power system oscillations. From the cases studied, voltage and the frequency variations were smaller than expected from the large-scale wind power integration due to the low spatial correlation of the wind speed. The voltage quality analysed in a Brazilian power system and in the Nordel power system from connecting large
Heterogeneous car buyers: a stylized fact

OpenAIRE

Ana M. Aizcorbe; Benjamin Bridgman; Jeremy J. Nalewaik

2009-01-01

Using a new dataset, we document a systematic pattern in the demographic characteristics of car buyers over the model year: as vehicle prices fall over the model year, so do buyer incomes. This pattern is consistent with price-insensitive buyers purchasing early in the year, while others wait until prices decline, and suggests price skimming (i.e. intertemporal price discrimination). Such consumer heterogeneity over the model year raises questions for measuring quality improvements in new goods.
Efficiency Wages in Heterogenous Labour Markets

OpenAIRE

Pavel Ryska; Jan Prùša

2011-01-01

In this paper we tackle two shortcomings of present efficiency wage models. Firstly, they do not fully account for labour heterogeneity, thus implying that high-effort and low-effort units of labour are interchangeable. Secondly, building on this assumed homogeneity of labour, the models derive involuntary unemployment from effort decisions of workers, which are patently voluntary. We offer a consistent reformulation of the theory: Each of the effort or quality levels is regarded as a separat...
Design considerations for large heterogeneous liquid-metal fast breeder reactors

International Nuclear Information System (INIS)

Tzanos, C.P.; Barthold, W.P.

1977-01-01

A systematic method for designing heterogeneous configurations having a near-zero value of sodium void reactivity is presented. It is based on the following principles: (a) the thickness of the internal blanket zones should be such that the reactivity change resulting from voiding any core zone is practically independent of any further increase in the thickness of these zones, and (b) the sodium void reactivity of each core zone must have a near-zero value. Neutronic coupling among the core zones of heterogeneous configurations decreases as the thickness of the internal blanket zones increases. To quantify coupling, Avery's coupling coefficients are used. Reduced coupling among the core zones of a heterogeneous design, compared to a homogeneous design, results in (a) increased sensitivity of the power distribution to enrichment distribution perturbations, (b) reduced reactivity worth of local perturbations, and (c) higher cladding temperatures during operational transients initiated by local perturbations. Heterogeneous designs compared to equivalent homogeneous designs have (a) lower core Doppler coefficient values, (b) larger fuel compaction reactivities, and (c) higher maximum cladding temperatures
An FPGA-based heterogeneous image fusion system design method

Science.gov (United States)

Song, Le; Lin, Yu-chi; Chen, Yan-hua; Zhao, Mei-rong

2011-08-01

Taking the advantages of FPGA's low cost and compact structure, an FPGA-based heterogeneous image fusion platform is established in this study. Altera's Cyclone IV series FPGA is adopted as the core processor of the platform, and the visible light CCD camera and infrared thermal imager are used as the image-capturing device in order to obtain dualchannel heterogeneous video images. Tailor-made image fusion algorithms such as gray-scale weighted averaging, maximum selection and minimum selection methods are analyzed and compared. VHDL language and the synchronous design method are utilized to perform a reliable RTL-level description. Altera's Quartus II 9.0 software is applied to simulate and implement the algorithm modules. The contrast experiments of various fusion algorithms show that, preferably image quality of the heterogeneous image fusion can be obtained on top of the proposed system. The applied range of the different fusion algorithms is also discussed.
Development of Real Time Implementation of 5/5 Rule based Fuzzy Logic Controller Shunt Active Power Filter for Power Quality Improvement

Science.gov (United States)

Puhan, Pratap Sekhar; Ray, Pravat Kumar; Panda, Gayadhar

2016-12-01

This paper presents the effectiveness of 5/5 Fuzzy rule implementation in Fuzzy Logic Controller conjunction with indirect control technique to enhance the power quality in single phase system, An indirect current controller in conjunction with Fuzzy Logic Controller is applied to the proposed shunt active power filter to estimate the peak reference current and capacitor voltage. Current Controller based pulse width modulation (CCPWM) is used to generate the switching signals of voltage source inverter. Various simulation results are presented to verify the good behaviour of the Shunt active Power Filter (SAPF) with proposed two levels Hysteresis Current Controller (HCC). For verification of Shunt Active Power Filter in real time, the proposed control algorithm has been implemented in laboratory developed setup in dSPACE platform.
Heterogeneous neutron-leakage model for PWR pin-by-pin calculation

International Nuclear Information System (INIS)

Li, Yunzhao; Zhang, Bin; Wu, Hongchun; Shen, Wei

2017-01-01

Highlights: •The derivation of the formula of the leakage model is introduced. This paper evaluates homogeneous and heterogeneous leakage models used in PWR pin-by-pin calculation. •The implements of homogeneous and heterogeneous leakage models used in pin-cell homogenization of the lattice calculation are studied. A consistent method of cooperation between the heterogeneous leakage model and the pin-cell homogenization theory is proposed. •Considering the computational cost, a new buckling search scheme is proposed to reach the convergence faster. The computational cost of the newly proposed neutron balance scheme is much less than the power-method scheme and the linear-interpolation scheme. -- Abstract: When assembly calculation is performed with the reflective boundary condition, a leakage model is usually required in the lattice code. The previous studies show that the homogeneous leakage model works effectively for the assembly homogenization. However, it becomes different and unsettled for the pin-cell homogenization. Thus, this paper evaluates homogeneous and heterogeneous leakage models used in pin-by-pin calculation. The implements of homogeneous and heterogeneous leakage models used in pin-cell homogenization of the lattice calculation are studied. A consistent method of cooperation between the heterogeneous leakage model and the pin-cell homogenization theory is proposed. Considering the computational cost, a new buckling search scheme is proposed to reach the convergence faster. For practical reactor-core applications, the diffusion coefficients determined by the transport cross-section or by the leakage model are compared with each other to determine which one is more accurate for the Pressurized Water Reactor pin-by-pin calculation. Numerical results have demonstrated that the heterogeneous leakage model together with the diffusion coefficient determined by the heterogeneous leakage model would have the higher accuracy. The new buckling search

C-E Nuclear Power Businesses Quality Management of Manufacturing and Design and its impact on Reliability of C-E Supplied Components

Energy Technology Data Exchange (ETDEWEB)

Mawhinney, D. [Combustion Engineering, Inc., Windsor (United States)

1989-04-15

To attain and sustain this objective, Nuclear Power Businesses has established a quality system for design and manufacturing of Nuclear Steam Supply System components, nuclear fuel and operating plant systems and services. Today's quality system has been designed, developed and refined over the past forty (40) years. This system is a dynamic one, based on solid quality principles, accepted industry standards and practices, complies with the ASME Code and 10 CFRP 50, Appendix B, but within the bounds of mandated requirements is adaptable to unique client needs. Nuclear Power Businesses is successfully implementing its quality philosophy through management and organizational commitment, strong leadership, teamwork and use of modern quality techniques. The quality system at C-E Nuclear Power Businesses has been developed in response to changing requirements over the past forty years. It is still changing today. The effectiveness of the system is evidenced by the superior performance of C-E Nuclear Power Businesses supplied Ness's. The system includes management involvement and awareness involvement and awareness and ensures that all employees are aware of Nuclear Power Businesses' quality goals. The system has a strong quality organization that establishes uniform policies and assures compliance. In addition, the system promotes open communication and prompt, permanent corrective action. Although we believe our system, as they exist today, meet or exceed client requirements, they are continuously reviewed and adjusted to improve their usefulness to make them more cost effective.
C-E Nuclear Power Businesses Quality Management of Manufacturing and Design and its impact on Reliability of C-E Supplied Components

International Nuclear Information System (INIS)

Mawhinney, D.

1989-01-01

To attain and sustain this objective, Nuclear Power Businesses has established a quality system for design and manufacturing of Nuclear Steam Supply System components, nuclear fuel and operating plant systems and services. Today's quality system has been designed, developed and refined over the past forty (40) years. This system is a dynamic one, based on solid quality principles, accepted industry standards and practices, complies with the ASME Code and 10 CFRP 50, Appendix B, but within the bounds of mandated requirements is adaptable to unique client needs. Nuclear Power Businesses is successfully implementing its quality philosophy through management and organizational commitment, strong leadership, teamwork and use of modern quality techniques. The quality system at C-E Nuclear Power Businesses has been developed in response to changing requirements over the past forty years. It is still changing today. The effectiveness of the system is evidenced by the superior performance of C-E Nuclear Power Businesses supplied Ness's. The system includes management involvement and awareness involvement and awareness and ensures that all employees are aware of Nuclear Power Businesses' quality goals. The system has a strong quality organization that establishes uniform policies and assures compliance. In addition, the system promotes open communication and prompt, permanent corrective action. Although we believe our system, as they exist today, meet or exceed client requirements, they are continuously reviewed and adjusted to improve their usefulness to make them more cost effective
Astrocytes regulate heterogeneity of presynaptic strengths in hippocampal networks

Science.gov (United States)

Letellier, Mathieu; Park, Yun Kyung; Chater, Thomas E.; Chipman, Peter H.; Gautam, Sunita Ghimire; Oshima-Takago, Tomoko; Goda, Yukiko

2016-01-01

Dendrites are neuronal structures specialized for receiving and processing information through their many synaptic inputs. How input strengths are modified across dendrites in ways that are crucial for synaptic integration and plasticity remains unclear. We examined in single hippocampal neurons the mechanism of heterosynaptic interactions and the heterogeneity of synaptic strengths of pyramidal cell inputs. Heterosynaptic presynaptic plasticity that counterbalances input strengths requires N-methyl-d-aspartate receptors (NMDARs) and astrocytes. Importantly, this mechanism is shared with the mechanism for maintaining highly heterogeneous basal presynaptic strengths, which requires astrocyte Ca2+ signaling involving NMDAR activation, astrocyte membrane depolarization, and L-type Ca2+ channels. Intracellular infusion of NMDARs or Ca2+-channel blockers into astrocytes, conditionally ablating the GluN1 NMDAR subunit, or optogenetically hyperpolarizing astrocytes with archaerhodopsin promotes homogenization of convergent presynaptic inputs. Our findings support the presence of an astrocyte-dependent cellular mechanism that enhances the heterogeneity of presynaptic strengths of convergent connections, which may help boost the computational power of dendrites. PMID:27118849
Evaluating the quality of scenarios of short-term wind power generation

DEFF Research Database (Denmark)

Pinson, Pierre; Girard, R.

2012-01-01

Scenarios of short-term wind power generation are becoming increasingly popular as input to multi-stage decision-making problems e.g. multivariate stochastic optimization and stochastic programming. The quality of these scenarios is intuitively expected to substantially impact the benets from...... their use in decision-making. So far however, their verication is almost always focused on their marginal distributions for each individual lead time only, thus overlooking their temporal interdependence structure. The shortcomings of such an approach are discussed. Multivariate verication tools, as well...... as diagnostic approaches based on event-based verication are then presented. Their application to the evaluation of various sets of scenarios of short-term wind power generation demonstrates them as valuable discrimination tools....
Quality assurance and control in constructing the Dukovany nuclear power plant

International Nuclear Information System (INIS)

Lujka, T.

1986-01-01

A quality control and assurance department was established on the Dukovany nuclear power plant site as a unit independent of the production divisions of the plant. Its responsibility consists in testing activities including the development of testing techniques and cooperation in the compilation of specifications and binding technological regulations. The department consists of five sections. The concrete laying laboratory has a staff of 7 and concentrates on testing the quality of concrete mixes and their components in the central concrete production plant. The materials testing centre with a staff of 5 provides testing of steel and special structures and oversees the laying of heavy and very heavy concretes. A separate unit for the testing of surface finish of building structures is staffed with 4 people. The section of technological checks of building and assembly work with a staff of 4 is responsible for the quality of work in the main production unit zone but also of the other buildings on the site. Two people staff the unit for checking and filing the quality control documents for selected components. (Z.M.)
Practical considerations of reservoir heterogeneities on SAGD projects

Energy Technology Data Exchange (ETDEWEB)

Baker, R.; Fong, C.; Li, T. [Epic Consulting Services Ltd., Calgary, AB (Canada); Bowes, C.; Toews, M. [Calgary Univ., AB (Canada)

2008-10-15

Significant emphasis has been placed on developing cost-effective strategies for the production of large heavy oil and bitumen reserves located in western Canada and around the world. An effective method that has been proven to be effective in this regard is steam-assisted gravity drainage (SAGD). However, determining the optimum and cost-effective strategy is a challenge to any SAGD reservoir. Average rock quality and reservoir heterogeneities have a significant impact on steam chamber development and the overall volumetric sweep. As well, the approach to SAGD simulation varies as heterogeneity changes. This paper examined two well pairs with different degrees of heterogeneity in the Surmont pilot project. The paper also addressed potential geological risk through analogy and the amount of heterogeneity that must be accounted for when developing a representative simulation. The paper provided background information on the Surmont pilot project, which consists of three horizontal SAGD well pairs in the Athabasca oil sands of northeast Alberta. The reservoir simulation model was then described. Results and conclusions were offered. It was concluded that careful production controls and strategy must be applied particular to the reservoir to ensure that the SAGD well pairs were capable of draining the mobilized oil. 5 refs., 1 tab., 25 figs.
Interference Mitigation for Coexistence of Heterogeneous Ultra-Wideband Systems

Directory of Open Access Journals (Sweden)

Wu Haitao

2006-01-01

Full Text Available Two ultra-wideband (UWB specifications, that is, direct-sequence (DS UWB and multiband-orthogonal frequency division multiplexing (MB-OFDM UWB, have been proposed as the candidates of the IEEE 802.15.3a, competing for the standard of high-speed wireless personal area networks (WPAN. Due to the withdrawal of the standardization process, the two heterogeneous UWB technologies will coexist in the future commercial market. In this paper, we investigate the mutual interference of such coexistence scenarios by physical layer Monte Carlo simulations. The results reveal that the coexistence severely degrades the performance of both UWB systems. Moreover, such interference is asymmetric due to the heterogeneity of the two systems. Therefore, we propose the goodput-oriented utility-based transmit power control (GUTPC algorithm for interference mitigation. The feasible condition and the convergence property of GUTPC are investigated, and the choice of the coefficients is discussed for fairness and efficiency. Numerical results demonstrate that GUTPC improves the goodput of the coexisting systems effectively and fairly with saved power.
The impact of hybrid energy storage on power quality, when high power pulsed DC loads are operated on a microgrid testbed

Science.gov (United States)

Kelley, Jay Paul

. This enables the generator to maintain its operation at levels of high efficiency thereby increasing the power quality of the AC bus. The work discussed here is aimed at evaluating how the use of energy storage impacts the power quality on MicroGrid's AC bus when high rate DC and AC loads are sourced simultaneously. Also HESM has been developed and evaluated as a mean to optimizing both the power and energy density of the energy storage installed.
The climate and air-quality benefits of wind and solar power in the United States

Science.gov (United States)

Millstein, Dev; Wiser, Ryan; Bolinger, Mark; Barbose, Galen

2017-09-01

Wind and solar energy reduce combustion-based electricity generation and provide air-quality and greenhouse gas emission benefits. These benefits vary dramatically by region and over time. From 2007 to 2015, solar and wind power deployment increased rapidly while regulatory changes and fossil fuel price changes led to steep cuts in overall power-sector emissions. Here we evaluate how wind and solar climate and air-quality benefits evolved during this time period. We find cumulative wind and solar air-quality benefits of 2015 US$29.7-112.8 billion mostly from 3,000 to 12,700 avoided premature mortalities, and cumulative climate benefits of 2015 US$5.3-106.8 billion. The ranges span results across a suite of air-quality and health impact models and social cost of carbon estimates. We find that binding cap-and-trade pollutant markets may reduce these cumulative benefits by up to 16%. In 2015, based on central estimates, combined marginal benefits equal 7.3 ¢ kWh-1 (wind) and 4.0 ¢ kWh-1 (solar).
Application of Devices and Systems Designed for Power Quality Monitoring and Assessment

Directory of Open Access Journals (Sweden)

Wiesław Gil

2014-03-01

Full Text Available The paper presents the problems associated with increasing demands on the equipment and systems for power quality assessment (PQ, installed at power substations. Difficulties are signaled due to current lack of standards defining the test methodology of measuring devices. The necessary device properties and the structure of a large system operated in real time and designed to assess the PQ are discussed. The usefulness of multi-channel analyzers featuring the identification and registration of transients is pointed out. The desirability of synchrophasor assessment implementation and device integration by standard PN-EN 61850 with other SAS devices is also justified.
Power quality in electrical networks with aeolian penetration. Case: The Turiguanó wind farm

International Nuclear Information System (INIS)

Sierra Gil, Eduardo; Coello Igarza, Daisnel; Pérez Lorenzo, Adonis

2013-01-01

In this work the problem of the aeolian generation is described regarding to the quality of the produced energy because the inverters, that distort the fundamental wave of tension and current, has been incorporate like one of the characteristics of the aeolian generation that use turbines of variable speed, together with the exports and imports of reactive power and the consequent decrease of the power factor; for this purpose takes a practical example, with real measures of reactive powers, power factor and harmonics, carried out in the Demonstrative Wind Farm of Turiguanó and others accumulated measures from the records of the technical documentation of the wind farm, exposing a methodology to determine, with the realized measures, the values of reactive powers, power factor and harmonics for each value of load degree of the wind farm and operation of the turbines. (author)
Success and failure of nuclear power plant Quality Assurance when applied to research and development activities

International Nuclear Information System (INIS)

Michels, R.D.; Stark, W.A.; Eberhart, C.F.

1986-01-01

Quality Assurance in some form or fashion has been practiced at research and development laboratories and facilities for quite some time. This quality assurance effort has largely been that of the scientist taking good notes as the experiment or observation is conducted to provide adequate documentation of the research and development effort. With the advent of the national laboratories participating in such projects as the Waste Isolation Project Plant (WIPP), Three Mile Island, and the National Waste Storage Program, a need for planned, systematic quality assurance for research and development activities has come into being. Based on experience evolved from nuclear power plant and facility construction, the government has chosen to utilize for these new projects the criteria developed for use in construction of power plants. While these criteria have worked reasonably well in the construction, maintenance, and operation of those nuclear plants, their application to research and development activities has not been an unqualified success. This paper compares and contrasts four criteria; surveillance, inspection, procurement, and calibration for application in the research and development situation, and nuclear power plants
Success and failure of nuclear power plant Quality Assurance when applied to research and development activities

Energy Technology Data Exchange (ETDEWEB)

Michels, R.D.; Stark, W.A.; Eberhart, C.F.

1986-01-01

Quality Assurance in some form or fashion has been practiced at research and development laboratories and facilities for quite some time. This quality assurance effort has largely been that of the scientist taking good notes as the experiment or observation is conducted to provide adequate documentation of the research and development effort. With the advent of the national laboratories participating in such projects as the Waste Isolation Project Plant (WIPP), Three Mile Island, and the National Waste Storage Program, a need for planned, systematic quality assurance for research and development activities has come into being. Based on experience evolved from nuclear power plant and facility construction, the government has chosen to utilize for these new projects the criteria developed for use in construction of power plants. While these criteria have worked reasonably well in the construction, maintenance, and operation of those nuclear plants, their application to research and development activities has not been an unqualified success. This paper compares and contrasts four criteria; surveillance, inspection, procurement, and calibration for application in the research and development situation, and nuclear power plants.
Mathematical game type optimization of powerful fast reactors

International Nuclear Information System (INIS)

Pavelesku, M.; Dumitresku, Kh.; Adam, S.

1975-01-01

To obtain maximum speed of putting into operation fast breeders it is recommended on the initial stage of putting into operation these reactors to apply lower power which needs less fission materials. That is why there is an attempt to find a configuration of a high-power reactor providing maximum power for minimum mass of fission material. This problem has a structure of the mathematical game with two partners of non-zero-order total and is solved by means of specific aids of theory of games. Optimal distribution of fission and breeding materials in a multizone reactor first is determined by solution of competitive game and then, on its base, by solution of the cooperation game. The second problem the solution for which is searched is developed from remark on the fact that a reactor with minimum coefficient of flux heterogenity has a configuration different from the reactor with power coefficient heterogenity. Maximum burn-up of fuel needs minimum heterogenity of the flux coefficient and the highest power level needs minimum coefficient of power heterogenity. That is why it is possible to put a problem of finding of the reactor configuration having both coefficients with minimum value. This problem has a structure of a mathematical game with two partners of non-zero-order total and is solved analogously giving optimal distribution of fuel from the new point of view. In the report is shown that both these solutions are independent which is a result of the aim put in the problem of optimization. (author)
Comparison between family power structure and the quality of parent-child interaction among the delinquent and non-delinquent adolescents.

Science.gov (United States)

Khodabakhshi Koolaee, Anahita; Shaghelani Lor, Hossein; Soleimani, Ali Akbar; Rahmatizadeh, Masoumeh

2014-06-01

Few studies indicate that most behavioral problems are due to family dysfunction and inappropriate family environment. It seems that the family of the delinquent adolescent is unbalanced in the power structure and parenting style. The present study compares the family power structure and parent-child relationship quality in delinquent and non-delinquent young subjects in Tehran. Eighty students of secondary schools aged between 15 and 18 in Tehran were enrolled with cluster sampling method and 80 delinquent adolescents of the Correction and Rehabilitation Centers aged between 15 and 18 were chosen with a convenience sampling method. They responded to an instrument of family power structure (Child-parents relationship inventory). Data was compared between these two groups by utilizing the independent and dependent t-test and Levene's test. The findings indicated there is a significant difference between delinquent and non-delinquent adolescents in family power structure and its subscales (P quality (P quality (P quality of parent-child relationship (P < 0.001). These results emphasize that an inappropriate decision making process pattern in a family has a significant effect on deviant behavior in adolescents. The fathers' parenting is more strongly linked to their sons' delinquency. So, family power structure and parent-child relationship can be considered in therapeutic interventions (prevention and treatment) for adolescents' delinquency.
Delay consequencies in the construction time-schedule of nuclear power plants in relation to its safety and quality

International Nuclear Information System (INIS)

Recalde, J.A.

1991-01-01

An important delay in the construction time-schedule of a Nuclear Power Plant affects its safety and quality. This mainly occurs as a consequence of four reasons: discontinuity of the personnel working for the project; discontinuities of project suppliers; new safety and quality concepts; long-term storage. This work analyses each of the above reasons so as to foresee countermeasures to garantee the non deterioration of a Nuclear Power Plant. (author)
Evaluation of heterogeneity corrections in stereotactic body radiation therapy for the lung

International Nuclear Information System (INIS)

Matsuo, Yukinori; Narita, Yuichiro; Nakata, Manabu

2008-01-01

The purpose was to evaluate impact of heterogeneity corrections on dose distributions for stereotactic body radiation therapy (SBRT) for the lung. This study was conducted with the treatment plans of 28 cases in which we performed SBRT for solitary lung tumors with 48 Gy in 12-Gy fractions at the isocenter. The treatment plans were recalculated under three conditions of heterogeneity correction as follows: pencil beam convolution with Batho power law correction (PBC-BPL), pencil beam convolution with no correction (PBC-NC), and anisotropic analytical algorithm with heterogeneity correction (AAA). Dose-volumetric data were compared among the three conditions. Heterogeneity corrections had a significant impact on all dose-volumetric parameters. Means of isocenter dose were 48.0 Gy, 44.6 Gy, and 48.4 Gy in PBC-BPL, PBC-NC, and AAA, respectively. PTV D95 were 45.2 Gy, 41.1 Gy, and 42.1 Gy, and V20 of the lung were 4.1%, 3.7%, and 3.9%, respectively. Significant differences in dose distribution were observed among heterogeneity corrections. Attention needs to be paid to the differences. (author)
Application of power ultrasound on the convective drying of fruits and vegetables: effects on quality.

Science.gov (United States)

Rodríguez, Óscar; Eim, Valeria; Rosselló, Carmen; Femenia, Antoni; Cárcel, Juan A; Simal, Susana

2018-03-01

Drying gives rise to products with a long shelf life by reducing the water activity to a level that is sufficiently low to inhibit the growth of microorganisms, enzymatic reactions and other deteriorative reactions. Despite the benefits of this operation, the quality of heat sensitive products is diminished when high temperatures are used. The use of low drying temperatures reduces the heat damage but, because of a longer drying time, oxidation reactions occur and a reduction of the quality is also observed. Thus, drying is a method that lends itself to being intensified. For this reason, alternative techniques are being studied. Power ultrasound is considered as an emerging and promising technology in the food industry. The potential of this technology relies on its ability to accelerate the mass transfer processes in solid-liquid and solid-gas systems. Intensification of the drying process with power ultrasound can be achieved by modifying the product behavior during drying, using pre-treatments such as soaking in a liquid medium assisted acoustically or, during the drying process itself, by applying power ultrasound in the gaseous medium. This review summarises the effects of the application of the power ultrasound on the quality of different dried products, such as fruits and vegetables, when the acoustic energy is intended to intensify the drying process, either when the application is performed before pretreatment or during the drying process. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.
Decomposition of heterogeneous organic matterand its long-term stabilization in soils

Science.gov (United States)

Sierra, Carlos A.; Harmon, Mark E.; Perakis, Steven S.

2011-01-01

Soil organic matter is a complex mixture of material with heterogeneous biological, physical, and chemical properties. Decomposition models represent this heterogeneity either as a set of discrete pools with different residence times or as a continuum of qualities. It is unclear though, whether these two different approaches yield comparable predictions of organic matter dynamics. Here, we compare predictions from these two different approaches and propose an intermediate approach to study organic matter decomposition based on concepts from continuous models implemented numerically. We found that the disagreement between discrete and continuous approaches can be considerable depending on the degree of nonlinearity of the model and simulation time. The two approaches can diverge substantially for predicting long-term processes in soils. Based on our alternative approach, which is a modification of the continuous quality theory, we explored the temporal patterns that emerge by treating substrate heterogeneity explicitly. The analysis suggests that the pattern of carbon mineralization over time is highly dependent on the degree and form of nonlinearity in the model, mostly expressed as differences in microbial growth and efficiency for different substrates. Moreover, short-term stabilization and destabilization mechanisms operating simultaneously result in long-term accumulation of carbon characterized by low decomposition rates, independent of the characteristics of the incoming litter. We show that representation of heterogeneity in the decomposition process can lead to substantial improvements in our understanding of carbon mineralization and its long-term stability in soils.
Evaluating the quality of scenarios of short-term wind power generation

International Nuclear Information System (INIS)

Pinson, P.; Girard, R.

2012-01-01

Highlights: ► Presentation of the desirable properties of wind power generation scenarios. ► Description of various evaluation frameworks (univariate, multivariate, diagnostic). ► Highlighting of the properties of current approaches to scenario generation. ► Guidelines for future evaluation/benchmark exercises. -- Abstract: Scenarios of short-term wind power generation are becoming increasingly popular as input to multistage decision-making problems e.g. multivariate stochastic optimization and stochastic programming. The quality of these scenarios is intuitively expected to substantially impact the benefits from their use in decision-making. So far however, their verification is almost always focused on their marginal distributions for each individual lead time only, thus overlooking their temporal interdependence structure. The shortcomings of such an approach are discussed. Multivariate verification tools, as well as diagnostic approaches based on event-based verification are then presented. Their application to the evaluation of various sets of scenarios of short-term wind power generation demonstrates them as valuable discrimination tools.

LOW-POWER AC LOADS AND ELECTRICAL POWER QUALITY

Directory of Open Access Journals (Sweden)

EPURE S.

2016-12-01

Full Text Available This paper deals with experimental study and numerical simulation of single phase AC low power loads: artificial light sources, personal computers, refrigeration units, air conditioning units and TV receivers. These loads are in such large numbers that represents the main source of disturbances (harmonic current, reactive power and unbalanced three-phase network. The obtained simulation models, verified by comparison with experimental results may be used in larger simulation models for testing and sizing the optimum parameters of active power filters. Models can also be used to study the interactions between grid elements and various loads or situations.
Simulation and Study of Power Quality Issues in a Fixed Speed Wind Farm Substation

Directory of Open Access Journals (Sweden)

T. Magesh

2015-01-01

Full Text Available Power quality issues associated with the fixed speed wind farm substation located at Coimbatore district are investigated as the wind generators are tripping frequently. The investigations are carried out using two power quality analyzers, Fluke 435 and Dranetz PX5.8, with one of them connected at group control breaker of the 110 kV feeder and the other at the selected 0.69 kV generator busbar during the period of maximum power generation. From the analysis of the recorded data it is found that sag, swell, and transients are the major events which are responsible for the tripping of the generators. In the present study, simulation models for wind, turbine, shaft, pitch mechanism, induction generator, and grid are developed using DIgSILENT. Using the turbine characteristics, a two-dimensional lookup table is designed to generate a reference pitch angle necessary to simulate the power curve of the passive stall controlled wind turbine. Various scenarios and their effects on the performance of the wind farm are studied and validated with the recorded data and waveforms. The simulation model will be useful for the designers for planning and development of the wind farm before implementation.
Effect of Lakhara chemical power station (LPTS) effluents on the river Indus water quality

International Nuclear Information System (INIS)

Mahar, R.B.; Memon, H.M.; Khushwar, M.Y.

2000-01-01

The variation of the quality of river Indus water with respect to the seasonal changes, discharge of water and dilution with the effluents of Lakhra Thermal Power Station (LTPS), has been monitored. The studies were focussed on the river Indus water quality before and after mixing the effluents of the power station. The samples were collected monthly from the representative locations of the river Indus, and analyzed for the residues (total, filterable, non-filterable, volatile and fixed), pH, temperature (air and water), conductance, chloride, hardness, alkalinity, dissolved oxygen (DO), chemical oxygen demand (COD), biochemical oxygen demand (BOD) /sub 5/- nitrate, phosphate, sulfate, ammonia, ammonium, silicates, magnesium, potassium, calcium and sodium. The results have been compared with the permissible limits of ECC (European Economic Community) standards for drinking and surface water. (author)
Evaluation on island ecological vulnerability and its spatial heterogeneity.

Science.gov (United States)

Chi, Yuan; Shi, Honghua; Wang, Yuanyuan; Guo, Zhen; Wang, Enkang

2017-12-15

The evaluation on island ecological vulnerability (IEV) can help reveal the comprehensive characteristics of the island ecosystem and provide reference for controlling human activities on islands. An IEV evaluation model which reflects the land-sea dual features, natural and anthropogenic attributes, and spatial heterogeneity of the island ecosystem was established, and the southern islands of Miaodao Archipelago in North China were taken as the study area. The IEV, its spatial heterogeneity, and its sensitivities to the evaluation elements were analyzed. Results indicated that the IEV was in status of mild vulnerability in the archipelago scale, and population pressure, ecosystem productivity, environmental quality, landscape pattern, and economic development were the sensitive elements. The IEV showed significant spatial heterogeneities both in land and surrounding waters sub-ecosystems. Construction scale control, optimization of development allocation, improvement of exploitation methods, and reasonable ecological construction are important measures to control the IEV. Copyright © 2017 Elsevier Ltd. All rights reserved.
Evaluation of conventional electric power generating industry quality assurance and reliability practices

Energy Technology Data Exchange (ETDEWEB)

Anderson, R.T.; Lauffenburger, H.A.

1981-03-01

The techniques and practices utilized in an allied industry (electric power generation) that might serve as a baseline for formulating Quality Assurance and Reliability (QA and R) procedures for photovoltaic solar energy systems were studied. The study results provide direct near-term input for establishing validation methods as part of the SERI performance criteria and test standards development task.
A 3D-Space Vector Modulation Algorithm for Three Phase Four Wire Neutral Point Clamped Inverter Systems as Power Quality Compensator

Directory of Open Access Journals (Sweden)

Palanisamy Ramasamy

2017-11-01

Full Text Available A Unified Power Quality Conditioner (UPQC is designed using a Neutral Point Clamped (NPC multilevel inverter to improve the power quality. When designed for high/medium voltage and power applications, the voltage stress across the switches and harmonic content in the output voltage are increased. A 3-phase 4-wire NPC inverter system is developed as Power Quality Conditioner using an effectual three dimensional Space Vector Modulation (3D-SVM technique. The proposed system behaves like a UPQC with shunt and series active filter under balanced and unbalanced loading conditions. In addition to the improvement of the power quality issues, it also balances the neutral point voltage and voltage balancing across the capacitors under unbalanced condition. The hardware and simulation results of proposed system are compared with 2D-SVM and 3D-SVM. The proposed system is stimulated using MATLAB and the hardware is designed using FPGA. From the results it is evident that effectual 3D-SVM technique gives better performance compared to other control methods.
Using technique vibration diagnostics for assessing the quality of power transmission line supports repairs

Directory of Open Access Journals (Sweden)

Cherpakov Aleksander

2017-01-01

Full Text Available The considered method for assessing the quality of the repair work to restore the rack supports of transmission lines is based on the method of vibration diagnostics. Power transmission line supports with a symmetrical destruction of the protective layer of concrete in the ground in violation of the construction section were chosen as an object. Finite element modelling package Ansys was used in assessing the quality of repair work. The example of evaluating the quality of repair using the relative adhesion defective area design criteria in the analysis of natural vibration frequencies is given.
A Heterogeneous Medium Analytical Benchmark

International Nuclear Information System (INIS)

Ganapol, B.D.

1999-01-01

A benchmark, called benchmark BLUE, has been developed for one-group neutral particle (neutron or photon) transport in a one-dimensional sub-critical heterogeneous plane parallel medium with surface illumination. General anisotropic scattering is accommodated through the Green's Function Method (GFM). Numerical Fourier transform inversion is used to generate the required Green's functions which are kernels to coupled integral equations that give the exiting angular fluxes. The interior scalar flux is then obtained through quadrature. A compound iterative procedure for quadrature order and slab surface source convergence provides highly accurate benchmark qualities (4- to 5- places of accuracy) results
Power Quality Control and Design of Power Converter for Variable-Speed Wind Energy Conversion System with Permanent-Magnet Synchronous Generator

Directory of Open Access Journals (Sweden)

Yüksel Oğuz

2013-01-01

Full Text Available The control strategy and design of an AC/DC/AC IGBT-PMW power converter for PMSG-based variable-speed wind energy conversion systems (VSWECS operation in grid/load-connected mode are presented. VSWECS consists of a PMSG connected to a AC-DC IGBT-based PWM rectifier and a DC/AC IGBT-based PWM inverter with LCL filter. In VSWECS, AC/DC/AC power converter is employed to convert the variable frequency variable speed generator output to the fixed frequency fixed voltage grid. The DC/AC power conversion has been managed out using adaptive neurofuzzy controlled inverter located at the output of controlled AC/DC IGBT-based PWM rectifier. In this study, the dynamic performance and power quality of the proposed power converter connected to the grid/load by output LCL filter is focused on. Dynamic modeling and control of the VSWECS with the proposed power converter is performed by using MATLAB/Simulink. Simulation results show that the output voltage, power, and frequency of VSWECS reach to desirable operation values in a very short time. In addition, when PMSG based VSWECS works continuously with the 4.5 kHz switching frequency, the THD rate of voltage in the load terminal is 0.00672%.
Power quality control and design of power converter for variable-speed wind energy conversion system with permanent-magnet synchronous generator.

Science.gov (United States)

Oğuz, Yüksel; Güney, İrfan; Çalık, Hüseyin

2013-01-01

The control strategy and design of an AC/DC/AC IGBT-PMW power converter for PMSG-based variable-speed wind energy conversion systems (VSWECS) operation in grid/load-connected mode are presented. VSWECS consists of a PMSG connected to a AC-DC IGBT-based PWM rectifier and a DC/AC IGBT-based PWM inverter with LCL filter. In VSWECS, AC/DC/AC power converter is employed to convert the variable frequency variable speed generator output to the fixed frequency fixed voltage grid. The DC/AC power conversion has been managed out using adaptive neurofuzzy controlled inverter located at the output of controlled AC/DC IGBT-based PWM rectifier. In this study, the dynamic performance and power quality of the proposed power converter connected to the grid/load by output LCL filter is focused on. Dynamic modeling and control of the VSWECS with the proposed power converter is performed by using MATLAB/Simulink. Simulation results show that the output voltage, power, and frequency of VSWECS reach to desirable operation values in a very short time. In addition, when PMSG based VSWECS works continuously with the 4.5 kHz switching frequency, the THD rate of voltage in the load terminal is 0.00672%.
Dispersal and individual quality in a long lived species

Science.gov (United States)

Cam, E.; Monnat, J.-Y.; Royle, J. Andrew

2004-01-01

The idea of differences in individual quality has been put forward in numerous long-term studies in long-lived species to explain differences in lifetime production among individuals. Despite the important role of individual heterogeneity in vital rates in demography, population dynamics and life history theory, the idea of 'individual quality' is elusive. It is sometimes assumed to be a static or dynamic individual characteristic. When considered as a dynamic trait, it is sometimes assumed to vary deterministically or stochastically, or to be confounded with the characteristics of the habitat. We addressed heterogeneity in reproductive performance among individuals established in higher-quality habitat in a long-lived seabird species. We used approaches to statistical inference based on individual random effects permitting quantification of heterogeneity in populations and assessment of individual variation from the population mean. We found evidence of heterogeneity in breeding probability, not success probability. We assessed the influence of dispersal on individual reproductive potential. Dispersal is likely to be destabilizing in species with high site and mate fidelity. We detected heterogeneity after dispersal, not before. Individuals may perform well regardless of quality before destabilization, including those that recruited in higher-quality habitat by chance, but only higher-quality individuals may be able to overcome the consequences of dispersal. Importantly, results differed when accounting for individual heterogeneity (an increase in mean breeding probability when individuals dispersed), or not (a decrease in mean breeding probability). In the latter case, the decrease in mean breeding probability may result from a substantial decrease in breeding probability in a few individuals and a slight increase in others. In other words, the pattern observed at the population mean level may not reflect what happens in the majority of individuals.
Heterogeneous Policies, Heterogeneous Technologies: The Case of Renewable Energy

International Nuclear Information System (INIS)

Nicolli, Francesco; Vona, Francesco

2014-07-01

This paper investigates empirically the effect of market regulation and renewable energy policies on innovation activity in different renewable energy technologies. For the EU countries and the years 1980 to 2007, we built a unique dataset containing information on patent production in eight different technologies, proxies of market regulation and technology-specific renewable energy policies. Our main findings show that lowering entry barriers is a more significant driver of renewable energy innovation than privatisation and un-bundling, but its effect varies across technologies, being stronger in technologies characterised by the potential entry of small, independent power producers. Additionally, the inducement effect of renewable energy policies is heterogeneous and more pronounced for wind, which is the only technology that is mature and has high technological potential. Finally, the ratification of the Kyoto protocol - determining a more stable and less uncertain policy framework - amplifies the inducement effect of both energy policy and market liberalisation. (authors)
Large deflection angle, high-power adaptive fiber optics collimator with preserved near-diffraction-limited beam quality.

Science.gov (United States)

Zhi, Dong; Ma, Yanxing; Chen, Zilun; Wang, Xiaolin; Zhou, Pu; Si, Lei

2016-05-15

We report on the development of a monolithic adaptive fiber optics collimator, with a large deflection angle and preserved near-diffraction-limited beam quality, that has been tested at a maximal output power at the 300 W level. Additionally, a new measurement method of beam quality (M2 factor) is developed. Experimental results show that the deflection angle of the collimated beam is in the range of 0-0.27 mrad in the X direction and 0-0.19 mrad in the Y direction. The effective working frequency of the device is about 710 Hz. By employing the new measurement method of the M2 factor, we calculate that the beam quality is Mx2=1.35 and My2=1.24, which is in agreement with the result from the beam propagation analyzer and is preserved well with the increasing output power.
Simplified nonplanar wafer bonding for heterogeneous device integration

Science.gov (United States)

Geske, Jon; Bowers, John E.; Riley, Anton

2004-07-01

We demonstrate a simplified nonplanar wafer bonding technique for heterogeneous device integration. The improved technique can be used to laterally integrate dissimilar semiconductor device structures on a lattice-mismatched substrate. Using the technique, two different InP-based vertical-cavity surface-emitting laser active regions have been integrated onto GaAs without compromising the quality of the photoluminescence. Experimental and numerical simulation results are presented.
Homogenization technique for strongly heterogeneous zones in research reactors

International Nuclear Information System (INIS)

Lee, J.T.; Lee, B.H.; Cho, N.Z.; Oh, S.K.

1991-01-01

This paper reports on an iterative homogenization method using transport theory in a one-dimensional cylindrical cell model developed to improve the homogenized cross sections fro strongly heterogeneous zones in research reactors. The flux-weighting homogenized cross sections are modified by a correction factor, the cell flux ratio under an albedo boundary condition. The albedo at the cell boundary is iteratively determined to reflect the geometry effects of the material properties of the adjacent cells. This method has been tested with a simplified core model of the Korea Multipurpose Research Reactor. The results demonstrate that the reaction rates of an off-center control shroud cell, the multiplication factor, and the power distribution of the reactor core are close to those of the fine-mesh heterogeneous transport model
Evolution of market shares with repeated purchases and heterogeneous network externalities

NARCIS (Netherlands)

M.C.W. Janssen (Maarten); E. Mendys

2007-01-01

textabstractWe investigate how market shares change when a new, superior technology exhibiting network externalities is introduced in a market initially dominated by an old technology. This is done under the assumption that consumers are heterogeneous in their valuation of technology quality and
Outcome of homogeneous and heterogeneous reactions in Darcy-Forchheimer flow with nonlinear thermal radiation and convective condition

Directory of Open Access Journals (Sweden)

T. Hayat

Full Text Available The present analysis aims to report the consequences of nonlinear radiation, convective condition and heterogeneous-homogeneous reactions in Darcy-Forchheimer flow over a non-linear stretching sheet with variable thickness. Non-uniform magnetic field and nonuniform heat generation/absorption are accounted. The governing boundary layer partial differential equations are converted into a system of nonlinear ordinary differential equations. The computations are organized and the effects of physical variables such as thickness parameter, power index, Hartman number, inertia and porous parameters, radiation parameter, Biot number, Prandtl number, ratio parameter, heat generation parameter and homogeneous-heterogeneous reaction parameter are investigated. The variations of skin friction coefficient and Nusselt number for different interesting variables are plotted and discussed. It is noticed that Biot number and heat generation variable lead to enhance the temperature distribution. The solutal boundary layer thickness decreases for larger homogeneous variable while reverse trend is seen for heterogeneous reaction. Keywords: Variable sheet thickness, Darcy-Forchheimer flow, Homogeneous-heterogeneous reactions, Power-law surface velocity, Convective condition, Heat generation/absorption, Nonlinear radiation
Design and Implementation of a High Quality Power Supply Scheme for Distributed Generation in a Micro-Grid

Directory of Open Access Journals (Sweden)

Mingchao Xia

2013-09-01

Full Text Available A low carbon, high efficiency and high quality power supply scheme for Distributed Generation (DG in a micro-grid is presented. A three-phase, four-leg DG grid-interfacing converter based on the improved structure of a Unified Power Quality Conditioner (UPQC, including a series converter and a parallel converter is adopted, and improved indirect and direct control strategies are proposed. It can be observed that these strategies effectively compensate for voltage sags, voltage swells and voltage distortion, as well as voltage power quality problems resulting from the nonlinear and unbalanced loads in a micro-grid. While solving the coupling interference from series–parallel, the grid-interfacing converter can achieve proper load power sharing in a micro-grid. In particular, an improved minimum-energy compensation method is proposed that can overcome the conventional compensation algorithm defects, ensure the load voltage’s phase angle stability, improve the voltage compensating ability and range, reduce the capacity and cost of converters, and reduce the shock of micro-grid switching between grid-connected mode and islanded mode. Moreover, the advantages/disadvantages and application situation of the two improved control strategies are analyzed. Finally, the performance of the proposed control strategies has been verified through a MATLAB/Simulink simulation under various operating conditions.
3D stacked chips from emerging processes to heterogeneous systems

CERN Document Server

Fettweis, Gerhard

2016-01-01

This book explains for readers how 3D chip stacks promise to increase the level of on-chip integration, and to design new heterogeneous semiconductor devices that combine chips of different integration technologies (incl. sensors) in a single package of the smallest possible size. The authors focus on heterogeneous 3D integration, addressing some of the most important challenges in this emerging technology, including contactless, optics-based, and carbon-nanotube-based 3D integration, as well as signal-integrity and thermal management issues in copper-based 3D integration. Coverage also includes the 3D heterogeneous integration of power sources, photonic devices, and non-volatile memories based on new materials systems. •Provides single-source reference to the latest research in 3D optoelectronic integration: process, devices, and systems; •Explains the use of wireless 3D integration to improve 3D IC reliability and yield; •Describes techniques for monitoring and mitigating thermal behavior in 3D I...
Large Banks of Negative Differential Resistance Nonlinear Loads: A Hidden Threat to Power System Quality

Directory of Open Access Journals (Sweden)

Mahmood Ahmad

2018-01-01

Full Text Available DSM (Demand Side Management is a short term and comparatively low cost solution for energy starved countries. Replacement of IB (Incandescent Bulbs with CFL (Compact Fluorescent Lamps has proved its success throughout the world. The same solution, at larger scale, was proposed to Pakistan to mitigate power shortage on short term basis. Accordingly in year 2008, ADB (Asian Development Bank conducted a study and it was found that replacement of conventional IB with 30 million CFL will result into series of benefits for the stake holders and above all the Environment. The study, unfortunately didn’t take enough consideration of effect of CFLs on the power system being nonlinear device and so the power quality issues remained a secondary consideration. The focus of this paper remains on the effect of such non-linear load on consumers, it also envisages the erratic behaviour of such large penetration of CFLs on direct single phase, three phase, digital as well as electromechanical energy meters, under different loading conditions e.g. resistive load, SMPS (Switch Mode Power Supply, half and full-wave rectifiers. It also reflects harmonic pollution caused by CFLs, their effect on power system quality and the registration ability of electromechanical as well as digital energy meters. To this end Harmonic spectrum was recorded up to the 31st harmonic.

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