Development of lightweight radiators for lunar based power systems

International Nuclear Information System (INIS)

Juhasz, A.J.; Bloomfield, H.S.

1994-05-01

This report discusses application of a new lightweight carbon-carbon (C-C) space radiator technology developed under the NASA Civil-Space Technology Initiative (CSTI) High Capacity Power Program to a 20 kWe lunar based power system. This system comprises a nuclear (SP-100 derivative) heat source, a Closed Brayton Cycle (CBC) power conversion unit with heat rejection by means of a plane radiator. The new radiator concept is based on a C-C composite heat pipe with integrally woven fins and a thin walled metallic liner for containment of the working fluid. Using measured areal specific mass values (1.5 kg/m2) for flat plate radiators, comparative CBC power system mass and performance calculations show significant advantages if conventional heat pipes for space radiators are replaced by the new C-C heat pipe technology

SP-100 power system conceptual design for lunar base applications

International Nuclear Information System (INIS)

Mason, L.S.; Bloomfield, H.S.; Hainley, D.C.

1989-01-01

A conceptual design is presented for a nuclear power system utilizing an SP-100 reactor and multiple Stirling cycle engines for operation on the lunar surface. Based on the results of this study, it was concluded that this power plant could be a viable option for an evolutionary lunar base. The design concept consists of a 2500 kWt (kilowatt thermal) SP-100 reactor coupled to eight free-piston Stirling engines. Two of the engines are held in reserve to provide conversion system redundancy. The remaining engines operate at 91.7 percent of their rated capacity of 150 kWe. The design power level for this system is 825 kWe. Each engine has a pumped heat-rejection loop connected to a heat pipe radiator. Power system performance, sizing, layout configurations, shielding options, and transmission line characteristics are described. System components and integration options are compared for safety, high performance, low mass, and ease of assembly. The power plant was integrated with a proposed human lunar base concept to ensure mission compatibility. This study should be considered a preliminary investigation; further studies are planned to investigate the effect of different technologies on this baseline design

Dynamic market behaviour of autonomous network based power systems

NARCIS (Netherlands)

Jokic, A.; Wittebol, E.H.M.; Bosch, van den P.P.J.

2006-01-01

Dynamic models of real-time markets are important since they lead to additional insights of the behavior and stability of power system markets. The main topic of this paper is the analysis of real-time market dynamics in a novel power system structure that is based on the concept of autonomous

Power system distributed oscilation detection based on Synchrophasor data

Science.gov (United States)

Ning, Jiawei

Along with increasing demand for electricity, integration of renewable energy and deregulation of power market, power industry is facing unprecedented challenges nowadays. Within the last couple of decades, several serious blackouts have been taking place in United States. As an effective approach to prevent that, power system small signal stability monitoring has been drawing more interests and attentions from researchers. With wide-spread implementation of Synchrophasors around the world in the last decade, power systems real-time online monitoring becomes much more feasible. Comparing with planning study analysis, real-time online monitoring would benefit control room operators immediately and directly. Among all online monitoring methods, Oscillation Modal Analysis (OMA), a modal identification method based on routine measurement data where the input is unmeasured ambient excitation, is a great tool to evaluate and monitor power system small signal stability. Indeed, high sampling Synchrophasor data around power system is fitted perfectly as inputs to OMA. Existing methods in OMA for power systems are all based on centralized algorithms applying at control centers only; however, with rapid growing number of online Synchrophasors the computation burden at control centers is and will be continually exponentially expanded. The increasing computation time at control center compromises the real-time feature of online monitoring. The communication efforts between substation and control center will also be out of reach. Meanwhile, it is difficult or even impossible for centralized algorithms to detect some poorly damped local modes. In order to avert previous shortcomings of centralized OMA methods and embrace the new changes in the power systems, two new distributed oscillation detection methods with two new decentralized structures are presented in this dissertation. Since the new schemes brought substations into the big oscillation detection picture, the proposed

An OPF based approach for assessing the minimal reactive power support for generators in deregulated power systems

International Nuclear Information System (INIS)

Wu, H.; Yu, C.W.; Xu, N.; Lin, X.J.

2008-01-01

Reactive power support is an important ancillary service for secure and reliable operation in power markets. It has recently been recognized that the reactive power support for a generator has two components: one for supporting its own real power transmission and the other for supplying reactive demand, improving system security, and controlling system voltage; and that only the second part should receive financial compensation in competitive power markets. This makes the problem of separating these two components a new focus of current research. An OPF based reactive power optimization model along with a power flow tracing based method is proposed in this paper to tackle this problem. The methodology is tested on four test systems. Detailed analysis of the results of the 39-bus test system is reported. (author)

A cooperative power trading system based on satisfaction space technology

International Nuclear Information System (INIS)

Matsumoto, K.; Maruo, T.; Mori, N.

2006-01-01

This paper proposed a new power trading system model designed to ensure customer cooperation with power suppliers. Designed as an Internet application, the cooperative power trading system modelled power markets using a satisfaction space technology A network model of electric power trading systems was developed to create a communication network system that consisted of suppliers, customers, and auctioneers. When demand exceeded supply, the auctioneer in the trading system requested power reductions from customers. Rewards were paid to maintain the degree of satisfaction of the customers. The supplier's evaluation function was defined as a function of market price and power supply. A power reducing method was developed using a combinatorial optimization technique. Suppliers and customers submitted bids for initial power trading quantities, while the auctioneer decided a market price based on bidding values. After receiving the market price, suppliers and customers submitted a second set of bids for expected power trading quantities. A power reduction plan was then developed by the auctioneer to balance the amount of power supply and demand. The system can be applied to customers whose evaluation functions cannot be estimated beforehand, as the auctioneer was able to choose the most efficient power reduction point selected by consumers using a maximum steep slope method. Simulations conducted to validate the trading system demonstrated that the system is capable of choosing efficient energy reduction plans. 6 refs., 4 tabs., 3 figs

A Space Based Solar Power Satellite System

Science.gov (United States)

Engel, J. M.; Polling, D.; Ustamujic, F.; Yaldiz, R.; et al.

2002-01-01

(SPoTS) supplying other satellites with energy. SPoTS is due to be commercially viable and operative in 2020. of Technology designed the SPoTS during a full-time design period of six weeks as a third year final project. The team, organized according to the principles of systems engineering, first conducted a literature study on space wireless energy transfer to select the most suitable candidates for use on the SPoTS. After that, several different system concepts have been generated and evaluated, the most promising concept being worked out in greater detail. km altitude. Each SPoTS satellite has a 50m diameter inflatable solar collector that focuses all received sunlight. Then, the received sunlight is further redirected by means of four pointing mirrors toward four individual customer satellites. A market-analysis study showed, that providing power to geo-stationary communication satellites during their eclipse would be most beneficial. At arrival at geo-stationary orbit, the focused beam has expended to such an extent that its density equals one solar flux. This means that customer satellites can continue to use their regular solar arrays during their eclipse for power generation, resulting in a satellite battery mass reduction. the customer satellites in geo-stationary orbit, the transmitted energy beams needs to be pointed with very high accuracy. Computations showed that for this degree of accuracy, sensors are needed, which are not mainstream nowadays. Therefore further research must be conducted in this area in order to make these high-accuracy-pointing systems commercially attractive for use on the SPoTS satellites around 2020. Total 20-year system lifetime cost for 18 SPoT satellites are estimated at approximately USD 6 billion [FY2001]. In order to compete with traditional battery-based satellite power systems or possible ground based wireless power transfer systems the price per kWh for the customer must be significantly lower than the present one

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.

System-Awareness for Agent-based Power System Control

DEFF Research Database (Denmark)

Heussen, Kai; Saleem, Arshad; Lind, Morten

2010-01-01

transition. This paper presents a concept for the representation and organization of control- and resource-allocation, enabling computational reasoning and system awareness. The principles are discussed with respect to a recently proposed Subgrid operation concept.......Operational intelligence in electric power systems is focused in a small number of control rooms that coordinate their actions. A clear division of responsibility and a command hierarchy organize system operation. With multi-agent based control systems, this control paradigm may be shifted...... to a more decentralized openaccess collaboration control paradigm. This shift cannot happen at once, but must fit also with current operation principles. In order to establish a scalable and transparent system control architecture, organizing principles have to be identified that allow for a smooth...

Electric Vehicle Based Battery Storages for Future Power System Regulation Services

DEFF Research Database (Denmark)

Pillai, Jayakrishnan Radhakrishna; Bak-Jensen, Birgitte

2009-01-01

supplying the reserve power requirements. This limited regulation services from conventional generators in the future power system calls for other new reserve power solutions like Electric Vehicle (EV) based battery storages. A generic aggregated EV based battery storage for long-term dynamic load frequency...

Small reactor power systems for manned planetary surface bases

Energy Technology Data Exchange (ETDEWEB)

Bloomfield, H.S.

1987-12-01

A preliminary feasibility study of the potential application of small nuclear reactor space power systems to manned planetary surface base missions was conducted. The purpose of the study was to identify and assess the technology, performance, and safety issues associated with integration of reactor power systems with an evolutionary manned planetary surface exploration scenario. The requirements and characteristics of a variety of human-rated modular reactor power system configurations selected for a range of power levels from 25 kWe to hundreds of kilowatts is described. Trade-off analyses for reactor power systems utilizing both man-made and indigenous shielding materials are provided to examine performance, installation and operational safety feasibility issues. The results of this study have confirmed the preliminary feasibility of a wide variety of small reactor power plant configurations for growth oriented manned planetary surface exploration missions. The capability for power level growth with increasing manned presence, while maintaining safe radiation levels, was favorably assessed for nominal 25 to 100 kWe modular configurations. No feasibility limitations or technical barriers were identified and the use of both distance and indigenous planetary soil material for human rated radiation shielding were shown to be viable and attractive options.

Small reactor power systems for manned planetary surface bases

International Nuclear Information System (INIS)

Bloomfield, H.S.

1987-12-01

A preliminary feasibility study of the potential application of small nuclear reactor space power systems to manned planetary surface base missions was conducted. The purpose of the study was to identify and assess the technology, performance, and safety issues associated with integration of reactor power systems with an evolutionary manned planetary surface exploration scenario. The requirements and characteristics of a variety of human-rated modular reactor power system configurations selected for a range of power levels from 25 kWe to hundreds of kilowatts is described. Trade-off analyses for reactor power systems utilizing both man-made and indigenous shielding materials are provided to examine performance, installation and operational safety feasibility issues. The results of this study have confirmed the preliminary feasibility of a wide variety of small reactor power plant configurations for growth oriented manned planetary surface exploration missions. The capability for power level growth with increasing manned presence, while maintaining safe radiation levels, was favorably assessed for nominal 25 to 100 kWe modular configurations. No feasibility limitations or technical barriers were identified and the use of both distance and indigenous planetary soil material for human rated radiation shielding were shown to be viable and attractive options

Impact Study of PMSG-Based Wind Power Penetration on Power System Transient Stability Using EEAC Theory

Directory of Open Access Journals (Sweden)

Zhongyi Liu

2015-11-01

Full Text Available Wind turbines with direct-driven permanent magnet synchronous generators (PMSGs are widely used in wind power generation. According to the dynamic characteristics of PMSGs, an impact analysis of PMSG-based wind power penetration on the transient stability of multi-machine power systems is carried out in this paper based on the theory of extended equal area criterion (EEAC. Considering the most severe PMSG integration situation, the changes in the system’s equivalent power-angle relationships after integrating PMSGs are studied in detail. The system’s equivalent mechanical input power and the fault period electrical output power curves are found to be mainly affected. The analysis demonstrates that the integration of PMSGs can cause either detrimental or beneficial effects on the system transient stability. It is determined by several factors, including the selection of the synchronous generators used to balance wind power, the reactive power control mode of PMSGs and the wind power penetration level. Two different simulation systems are also adopted to verify the analysis results.

Power Forecasting of Combined Heating and Cooling Systems Based on Chaotic Time Series

Directory of Open Access Journals (Sweden)

Liu Hai

2015-01-01

Full Text Available Theoretic analysis shows that the output power of the distributed generation system is nonlinear and chaotic. And it is coupled with the microenvironment meteorological data. Chaos is an inherent property of nonlinear dynamic system. A predicator of the output power of the distributed generation system is to establish a nonlinear model of the dynamic system based on real time series in the reconstructed phase space. Firstly, chaos should be detected and quantified for the intensive studies of nonlinear systems. If the largest Lyapunov exponent is positive, the dynamical system must be chaotic. Then, the embedding dimension and the delay time are chosen based on the improved C-C method. The attractor of chaotic power time series can be reconstructed based on the embedding dimension and delay time in the phase space. By now, the neural network can be trained based on the training samples, which are observed from the distributed generation system. The neural network model will approximate the curve of output power adequately. Experimental results show that the maximum power point of the distributed generation system will be predicted based on the meteorological data. The system can be controlled effectively based on the prediction.

Parallel combination of FC and UC for vehicular power systems using a multi-input converter-based power interface

Energy Technology Data Exchange (ETDEWEB)

Vural, B.; Erdinc, O.; Uzunoglu, M. [Department of Electrical Engineering, Yildiz Technical University, Istanbul 34349 (Turkey)

2010-12-15

Fuel cells (FC) are widely recognized as one of the most promising technologies to meet future power requirements of vehicular applications. However, a FC system combined with an energy storage system (ESS) can perform better for vehicle propulsion as considering several points. As the additional ESS can fulfill the transient power demand fluctuations, the FC system can be downsized to fit the base power demand without facing peak loads. Besides, braking energy can be recovered by the ESS. Interfacing of traction drive requirements with characteristics and modes of operation of on-board generation units and ESSs calls for suitable power electronic converter configuration. In this paper, a FC/UC hybrid vehicular power system using a multi-input converter-based power interface is proposed. The applied power interface topology ensures the active power sharing and DC link voltage stabilization for the hybrid vehicular system. The mathematical and electrical models of the hybrid vehicular system are developed in detail and simulated using MATLAB registered, Simulink registered and SimPowerSystems registered environments. (author)

Parallel combination of FC and UC for vehicular power systems using a multi-input converter-based power interface

International Nuclear Information System (INIS)

Vural, B.; Erdinc, O.; Uzunoglu, M.

2010-01-01

Fuel cells (FC) are widely recognized as one of the most promising technologies to meet future power requirements of vehicular applications. However, a FC system combined with an energy storage system (ESS) can perform better for vehicle propulsion as considering several points. As the additional ESS can fulfill the transient power demand fluctuations, the FC system can be downsized to fit the base power demand without facing peak loads. Besides, braking energy can be recovered by the ESS. Interfacing of traction drive requirements with characteristics and modes of operation of on-board generation units and ESSs calls for suitable power electronic converter configuration. In this paper, a FC/UC hybrid vehicular power system using a multi-input converter-based power interface is proposed. The applied power interface topology ensures the active power sharing and DC link voltage stabilization for the hybrid vehicular system. The mathematical and electrical models of the hybrid vehicular system are developed in detail and simulated using MATLAB (registered) , Simulink (registered) and SimPowerSystems (registered) environments.

Performance Based Failure Criteria of the Base Isolation System for Nuclear Power Plants

International Nuclear Information System (INIS)

Kim, Jung Han; Kim, Min Kyu; Choi, In Kil

2013-01-01

The realistic approach to evaluate the failure state of the base isolation system is necessary. From this point of view, several concerns are reviewed and discussed in this study. This is the preliminary study for the performance based risk assessment of a base isolated nuclear power plant. The items to evaluate the capacity and response of an individual base isolator and a base isolation system were briefly outlined. However, the methodology to evaluate the realistic fragility of a base isolation system still needs to be specified. For the quantification of the seismic risk for a nuclear power plant structure, the failure probabilities of the structural component for the various seismic intensity levels need to be calculated. The failure probability is evaluated as the probability when the seismic response of a structure exceeds the failure criteria. Accordingly, the failure mode of the structural system caused by an earthquake vibration should be defined first. The type of a base isolator appropriate for a nuclear power plant structure is regarded as an elastometric rubber bearing with a lead core. The failure limit of the lead-rubber bearing (LRB) is not easy to be predicted because of its high nonlinearity and a complex loading condition by an earthquake excitation. Furthermore, the failure mode of the LRB system installed below the nuclear island cannot be simply determined because the basemat can be sufficiently supported if the number of damaged isolator is not much

Knowledge-based and integrated monitoring and diagnosis in autonomous power systems

Science.gov (United States)

Momoh, J. A.; Zhang, Z. Z.

1990-01-01

A new technique of knowledge-based and integrated monitoring and diagnosis (KBIMD) to deal with abnormalities and incipient or potential failures in autonomous power systems is presented. The KBIMD conception is discussed as a new function of autonomous power system automation. Available diagnostic modelling, system structure, principles and strategies are suggested. In order to verify the feasibility of the KBIMD, a preliminary prototype expert system is designed to simulate the KBIMD function in a main electric network of the autonomous power system.

Novel power MOSFET-based expander for high frequency ultrasound systems.

Science.gov (United States)

Choi, Hojong; Shung, K Kirk

2014-01-01

The function of an expander is to obstruct the noise signal transmitted by the pulser so that it does not pass into the transducer or receive electronics, where it can produce undesirable ring-down in an ultrasound imaging application. The most common type is a diode-based expander, which is essentially a simple diode-pair, is widely used in pulse-echo measurements and imaging applications because of its simple architecture. However, diode-based expanders may degrade the performance of ultrasonic transducers and electronic components on the receiving and transmitting sides of the ultrasound systems, respectively. Since they are non-linear devices, they cause excessive signal attenuation and noise at higher frequencies and voltages. In this paper, a new type of expander that utilizes power MOSFET components, which we call a power MOSFET-based expander, is introduced and evaluated for use in high frequency ultrasound imaging systems. The performance of a power MOSFET-based expander was evaluated relative to a diode-based expander by comparing the noise figure (NF), insertion loss (IL), total harmonic distortion (THD), response time (RT), electrical impedance (EI) and dynamic power consumption (DPC). The results showed that the power MOSFET-based expander provided better NF (0.76 dB), IL (-0.3 dB) and THD (-62.9 dB), and faster RT (82 ns) than did the diode-based expander (NF (2.6 dB), IL (-1.4 dB), THD (-56.0 dB) and RT (119 ns)) at 70 MHz. The -6 dB bandwidth and the peak-to-peak voltage of the echo signal received by the transducer using the power MOSFET-based expander improved by 17.4% and 240% compared to the diode-based expander, respectively. The new power MOSFET-based expander was shown to yield lower NF, IL and THD, faster RT and lower ring down than the diode-based expander at the expense of higher dynamic power consumption. Copyright © 2013 Elsevier B.V. All rights reserved.

Appliance based control for Home Power Management Systems

International Nuclear Information System (INIS)

Özkan, Hanife Apaydın

2016-01-01

This study scrutinizes energy-friendly smart home appliances (hereafter ‘smart appliances’), control of these appliances and their effects on the efficient use of energy. To accomplish this, smart appliances and their operation principles are introduced and their energy savings compared to conventional appliances are analyzed using precise measurements. Then, a real-time Appliance-based Home Power Management System (Ab-HPMS) which manages power consumption of smart appliances and that of the house as a whole is proposed. For Ab-HPMS, an appliance control algorithm, called Appliance-based Rolling Wave Planning (Ab-RWP), is developed with the aim of reducing electricity cost and improving energy efficiency while maintaining user comfort. Ab-RWP algorithm interacts with appliances in a priority order based on user comfort which is determined by utilizing their smart operational characteristics. Operations of smart appliances and their integrations with Ab-HPMS are modeled with Petri nets to verify that they meet the requirements expressed in the specifications. Simulation results demonstrate that proposed Ab-HPMS provides improvements in terms of the energy consumption reduction of about 5%–16%, cost reduction of about 10%–24% and peak reduction at high demand period of about 38%–53% compared to conventional appliances usage. - Highlights: • The effects of smart home appliances on energy saving are investigated. • Petri nets models of smart appliances are developed to simulate their operations in smart home. • A real-time appliance-based home power management system (Ab-HPMS) is proposed. • Power density function is evaluated to interrupt the operation of smart washing machine.

Market-based multiagent system for reconfiguration of shipboard power systems

International Nuclear Information System (INIS)

Huang, Kai; Srivastava, Sanjeev K.; Cartes, David A.; Sun, Li-Hsiang

2009-01-01

On ships, the electric shipboard power system (SPS) supplies electrical power to critical functions such as navigation, communication, emergency systems, and in the case of warships, weapon systems. During ship operation, some parts of the SPS may become unavailable due to damage, fault, or maintenance. For the survivability and reliability of ships, it is desired to make the SPS highly reconfigurable. This paper presents a market-based multiagent system (MAS) for the reconfiguration of radial SPS. Radial SPSs are found on majority of ships. In the proposed MAS, each agent only communicates with its neighbor agents to make the system work in a fully decentralized manner. The MAS is implemented using Java Agent Development Framework (JADE), which is fully implemented in Java and compliant with Foundation of Intelligent Physical Agents (FIPA). An SPS with two generators and four loads is used for testing the proposed MAS. The results show the proposed MAS can successfully reconfigure a radial SPS. (author)

Reliability of IGBT-based power devices in the viewpoint of applications in future power supply systems

International Nuclear Information System (INIS)

Lutz, J.

2011-01-01

IGBT-based high-voltage power devices will be key components for future renewable energy base of the society. Windmills in the range up to 10 MW use converters with IGBTs. HVDC systems with IGBT-based voltage source converters have the advantage of a lower level of harmonics, less efforts for filters and more possibilities for control. The power devices need a lifetime expectation of several ten years. The lifetime is determined by the reliability of the packaging technology. IGBTs are offered packaged in presspacks and modules. The presentation will have the focus on IGBT high power modules. Accelerated power cycling tests for to determine the end-of-life at given conditions and their results are shown. models to calculate the lifetime, and actual work in research for systems with increased reliability.

Power MOSFET-diode-based limiter for high-frequency ultrasound systems.

Science.gov (United States)

Choi, Hojong; Kim, Min Gon; Cummins, Thomas M; Hwang, Jae Youn; Shung, K Kirk

2014-10-01

The purpose of the limiter circuits used in the ultrasound imaging systems is to pass low-voltage echo signals generated by ultrasonic transducers while preventing high-voltage short pulses transmitted by pulsers from damaging front-end circuits. Resistor-diode-based limiters (a 50 Ω resistor with a single cross-coupled diode pair) have been widely used in pulse-echo measurement and imaging system applications due to their low cost and simple architecture. However, resistor-diode-based limiters may not be suited for high-frequency ultrasound transducer applications since they produce large signal conduction losses at higher frequencies. Therefore, we propose a new limiter architecture utilizing power MOSFETs, which we call a power MOSFET-diode-based limiter. The performance of a power MOSFET-diode-based limiter was evaluated with respect to insertion loss (IL), total harmonic distortion (THD), and response time (RT). We compared these results with those of three other conventional limiter designs and showed that the power MOSFET-diode-based limiter offers the lowest IL (-1.33 dB) and fastest RT (0.10 µs) with the lowest suppressed output voltage (3.47 Vp-p) among all the limiters at 70 MHz. A pulse-echo test was performed to determine how the new limiter affected the sensitivity and bandwidth of the transducer. We found that the sensitivity and bandwidth of the transducer were 130% and 129% greater, respectively, when combined with the new power MOSFET-diode-based limiter versus the resistor-diode-based limiter. Therefore, these results demonstrate that the power MOSFET-diode-based limiter is capable of producing lower signal attenuation than the three conventional limiter designs at higher frequency operation. © The Author(s) 2014.

Simulation of SOFCs based power generation system using Aspen

Directory of Open Access Journals (Sweden)

Pianko-Oprych Paulina

2017-12-01

Full Text Available This study presents a thermodynamic Aspen simulation model for Solid Oxide Fuel Cells, SOFCs, based power generation system. In the first step, a steady-state SOFCs system model was developed. The model includes the electrochemistry and the diffusion phenomena. The electrochemical model gives good agreement with experimental data in a wide operating range. Then, a parametric study has been conducted to estimate effects of the oxygen to carbon ratio, O/C, on reformer temperature, fuel cell temperature, fuel utilization, overall fuel cell performance, and the results are discussed in this paper. In the second step, a dynamic analysis of SOFCs characteristic has been developed. The aim of dynamic modelling was to find the response of the system against the fuel utilization and the O/C ratio variations. From the simulations, it was concluded that both developed models in the steady and dynamic state were reasonably accurate and can be used for system level optimization studies of the SOFC based power generation system.

The control system based on PXI technology for high voltage power supply

International Nuclear Information System (INIS)

Chen Dehong; Zhang Ming; Ma Shaoxiang; Xia Linglong; Zeng Zhen; Zhang Xueliang; Wang Chuliang; Yu Kexun

2014-01-01

A 100 kV/60 A high voltage power supply (HVPS) is being developed to carry some auxiliary heating research on J-TEXT and supply the auxiliary heating system. The power supply which consists of 144 switch modules is based on PSM technology. For the requirement of isolation, control and protection, a control system based on the PCI extensions for instrumentation (PXI) which meets up with the CODAC standards is designed with developed PSM technology for the high voltage power supply. The compact structure of hardware in the control system is presented too. And the control strategy which is based on shift phase pulse width modulation is discussed Some tests are performed on the control system to validate the control strategy, the experimental results show that the system has a good control performance and fast response, which meets the control requirement of 100 kV/60 A high voltage power supply. (authors)

Design of EAST LHCD high power supply feedback control system based on PLC

International Nuclear Information System (INIS)

Hu Huaichuan; Shan Jiafang

2009-01-01

Design of EAST LHCD -35kV/5.6MW high power supply feedback control system based on PLC is described. Industrial computer and PLC are used to control high power supply in the system. PID arithmetic is adopted to achieve the feedback control of voltage of high power supply. Operating system is base on real-time operating system of QNX. Good controlling properties and reliable protective properties of the feedback control system are proved by the experiment results. (authors)

Power management circuits for self-powered systems based on micro-scale solar energy harvesting

Science.gov (United States)

Yoon, Eun-Jung; Yu, Chong-Gun

2016-03-01

In this paper, two types of power management circuits for self-powered systems based on micro-scale solar energy harvesting are proposed. First, if a solar cell outputs a very low voltage, less than 0.5 V, as in miniature solar cells or monolithic integrated solar cells, such that it cannot directly power the load, a voltage booster is employed to step up the solar cell's output voltage, and then a power management unit (PMU) delivers the boosted voltage to the load. Second, if the output voltage of a solar cell is enough to drive the load, the PMU directly supplies the load with solar energy. The proposed power management systems are designed and fabricated in a 0.18-μm complementary metal-oxide-semiconductor process, and their performances are compared and analysed through measurements.

Internet-based wide area measurement applications in deregulated power systems

Science.gov (United States)

Khatib, Abdel-Rahman Amin

Since the deregulation of power systems was started in 1989 in the UK, many countries have been motivated to undergo deregulation. The United State started deregulation in the energy sector in California back in 1996. Since that time many other states have also started the deregulation procedures in different utilities. Most of the deregulation market in the United States now is in the wholesale market area, however, the retail market is still undergoing changes. Deregulation has many impacts on power system network operation and control. The number of power transactions among the utilities has increased and many Independent Power Producers (IPPs) now have a rich market for competition especially in the green power market. The Federal Energy Regulatory Commission (FERC) called upon utilities to develop the Regional Transmission Organization (RTO). The RTO is a step toward the national transmission grid. RTO is an independent entity that will operate the transmission system in a large region. The main goal of forming RTOs is to increase the operation efficiency of the power network under the impact of the deregulated market. The objective of this work is to study Internet based Wide Area Information Sharing (WAIS) applications in the deregulated power system. The study is the first step toward building a national transmission grid picture using information sharing among utilities. Two main topics are covered as applications for the WAIS in the deregulated power system, state estimation and Total Transfer Capability (TTC) calculations. As a first step for building this national transmission grid picture, WAIS and the level of information sharing of the state estimation calculations have been discussed. WAIS impacts to the TTC calculations are also covered. A new technique to update the TTC using on line measurements based on WAIS created by sharing state estimation is presented.

Security attack detection algorithm for electric power gis system based on mobile application

Science.gov (United States)

Zhou, Chao; Feng, Renjun; Wang, Liming; Huang, Wei; Guo, Yajuan

2017-05-01

Electric power GIS is one of the key information technologies to satisfy the power grid construction in China, and widely used in power grid construction planning, weather, and power distribution management. The introduction of electric power GIS based on mobile applications is an effective extension of the geographic information system that has been widely used in the electric power industry. It provides reliable, cheap and sustainable power service for the country. The accurate state estimation is the important conditions to maintain the normal operation of the electric power GIS. Recent research has shown that attackers can inject the complex false data into the power system. The injection attack of this new type of false data (load integrity attack LIA) can successfully bypass the routine detection to achieve the purpose of attack, so that the control center will make a series of wrong decision. Eventually, leading to uneven distribution of power in the grid. In order to ensure the safety of the electric power GIS system based on mobile application, it is very important to analyze the attack mechanism and propose a new type of attack, and to study the corresponding detection method and prevention strategy in the environment of electric power GIS system based on mobile application.

Rolling scheduling of electric power system with wind power based on improved NNIA algorithm

Science.gov (United States)

Xu, Q. S.; Luo, C. J.; Yang, D. J.; Fan, Y. H.; Sang, Z. X.; Lei, H.

2017-11-01

This paper puts forth a rolling modification strategy for day-ahead scheduling of electric power system with wind power, which takes the operation cost increment of unit and curtailed wind power of power grid as double modification functions. Additionally, an improved Nondominated Neighbor Immune Algorithm (NNIA) is proposed for solution. The proposed rolling scheduling model has further improved the operation cost of system in the intra-day generation process, enhanced the system’s accommodation capacity of wind power, and modified the key transmission section power flow in a rolling manner to satisfy the security constraint of power grid. The improved NNIA algorithm has defined an antibody preference relation model based on equal incremental rate, regulation deviation constraints and maximum & minimum technical outputs of units. The model can noticeably guide the direction of antibody evolution, and significantly speed up the process of algorithm convergence to final solution, and enhance the local search capability.

Integrated Multimedia Based Intelligent Group Decision Support System for Electrical Power Network

Directory of Open Access Journals (Sweden)

Ajay Kumar Saxena

2002-05-01

Full Text Available Electrical Power Network in recent time requires an intelligent, virtual environment based decision process for the coordination of all its individual elements and the interrelated tasks. Its ultimate goal is to achieve maximum productivity and efficiency through the efficient and effective application of generation, transmission, distribution, pricing and regulatory systems. However, the complexity of electrical power network and the presence of conflicting multiple goals and objectives postulated by various groups emphasized the need of an intelligent group decision support system approach in this field. In this paper, an Integrated Multimedia based Intelligent Group Decision Support System (IM1GDSS is presented, and its main components are analyzed and discussed. In particular attention is focused on the Data Base, Model Base, Central Black Board (CBB and Multicriteria Futuristic Decision Process (MFDP module. The model base interacts with Electrical Power Network Load Forecasting and Planning (EPNLFP Module; Resource Optimization, Modeling and Simulation (ROMAS Module; Electrical Power Network Control and Evaluation Process (EPNCAEP Module, and MFDP Module through CBB for strategic planning, management control, operational planning and transaction processing. The richness of multimedia channels adds a totally new dimension in a group decision making for Electrical Power Network. The proposed IMIGDSS is a user friendly, highly interactive group decision making system, based on efficient intelligent and multimedia communication support for group discussions, retrieval of content and multi criteria decision analysis.

Fuzzy logic based power-efficient real-time multi-core system

CERN Document Server

Ahmed, Jameel; Najam, Shaheryar; Najam, Zohaib

2017-01-01

This book focuses on identifying the performance challenges involved in computer architectures, optimal configuration settings and analysing their impact on the performance of multi-core architectures. Proposing a power and throughput-aware fuzzy-logic-based reconfiguration for Multi-Processor Systems on Chip (MPSoCs) in both simulation and real-time environments, it is divided into two major parts. The first part deals with the simulation-based power and throughput-aware fuzzy logic reconfiguration for multi-core architectures, presenting the results of a detailed analysis on the factors impacting the power consumption and performance of MPSoCs. In turn, the second part highlights the real-time implementation of fuzzy-logic-based power-efficient reconfigurable multi-core architectures for Intel and Leone3 processors. .

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.

Management of a power system based on renewable energy

Directory of Open Access Journals (Sweden)

Ronay Karoly

2012-06-01

Full Text Available This article main purpose is to highlight the main advantage of the hardware and software implementation for an energy management system based on renewable energy sources. By using implemented and dedicated hardware and software the evolution of energy production and consumption can be monitored. The advantages of such system are highlighted by the results obtained from experimental simulations. An experimental model for the power system based on renewable energy sources was implemented, where the actual status of the system in different situations when the equipments change their own statuses can be shown.

An AI-based layout design system for nuclear power plants

International Nuclear Information System (INIS)

Fujita, Kikuo; Akagi, Shinsuke; Nakatogawa, Tetsundo; Tanaka, Kazuo; Takeuchi, Makoto.

1991-01-01

An AI-based layout design system for nuclear power plants has been developed. The design of the layout of nuclear power plants is a time-consuming task requiring expertise, in which a lot of machinery and equipment must be arranged in a plant building considering various kinds of design constraints, i.e. spatial, functional, economical etc. Computer aided layout design systems have been widely expected and the application of AI technology is expected as a promising approach for the synthesis phase of this task. In this paper, we present an approach to the layout design of nuclear power plants based on a constraint-directed search; one of the AI techniques. In addition, we show how it was implemented with an object-oriented programming technique and give an example of its application. (author)

Knowledge-based systems for power management

Science.gov (United States)

Lollar, L. F.

1992-01-01

NASA-Marshall's Electrical Power Branch has undertaken the development of expert systems in support of further advancements in electrical power system automation. Attention is given to the features (1) of the Fault Recovery and Management Expert System, (2) a resource scheduler or Master of Automated Expert Scheduling Through Resource Orchestration, and (3) an adaptive load-priority manager, or Load Priority List Management System. The characteristics of an advisory battery manager for the Hubble Space Telescope, designated the 'nickel-hydrogen expert system', are also noted.

Web-based online system for recording and examing of events in power plants

International Nuclear Information System (INIS)

Seyd Farshi, S.; Dehghani, M.

2004-01-01

Occurrence of events in power plants could results in serious drawbacks in generation of power. This suggests high degree of importance for online recording and examing of events. In this paper an online web-based system is introduced, which records and examines events in power plants. Throughout the paper, procedures for design and implementation of this system, its features and results gained are explained. this system provides predefined level of online access to all data of events for all its users in power plants, dispatching, regional utilities and top-level managers. By implementation of electric power industry intranet, an expandable modular system to be used in different sectors of industry is offered. Web-based online recording and examing system for events offers the following advantages: - Online recording of events in power plants. - Examing of events in regional utilities. - Access to event' data. - Preparing managerial reports

The future of GPS-based electric power system measurements, operation and control

Energy Technology Data Exchange (ETDEWEB)

Rizy, D.T. [Oak Ridge National Lab., TN (United States); Wilson, R.E. [Western Area Power Administration, Golden, CO (United States); Martin, K.E.; Litzenberger, W.H. [Bonneville Power Administration, Portland, OR (United States); Hauer, J.F. [Pacific Northwest National Lab., Richland, WA (United States); Overholt, P.N. [Dept. of Energy, Washington, DC (United States); Sobajic, D.J. [Electric Power Research Inst., Palo Alto, CA (United States)

1998-11-01

Much of modern society is powered by inexpensive and reliable electricity delivered by a complex and elaborate electric power network. Electrical utilities are currently using the Global Positioning System-NAVSTAR (GPS) timekeeping to improve the network`s reliability. Currently, GPS synchronizes the clocks on dynamic recorders and aids in post-mortem analysis of network disturbances. Two major projects have demonstrated the use of GPS-synchronized power system measurements. In 1992, the Electric Power Research Institute`s (EPRI) sponsored Phase Measurements Project used a commercially available Phasor Measurements Unit (PMU) to collect GPS-synchronized measurements for analyzing power system problems. In 1995, Bonneville Power Administration (BPA) and Western Area Power Administration (WAPA) under DOE`s and EPRI`s sponsorship launched the Wide Area Measurements (WAMS) project. WAMS demonstrated GPS-synchronized measurements over a large area of their power networks and demonstrated the networking of GPS-based measurement systems in BPA and WAPA. The phasor measurement technology has also been used to conduct dynamic power system tests. During these tests, a large dynamic resistor was inserted to simulate a small power system disturbance.

Autonomous power expert fault diagnostic system for Space Station Freedom electrical power system testbed

Science.gov (United States)

Truong, Long V.; Walters, Jerry L.; Roth, Mary Ellen; Quinn, Todd M.; Krawczonek, Walter M.

1990-01-01

The goal of the Autonomous Power System (APS) program is to develop and apply intelligent problem solving and control to the Space Station Freedom Electrical Power System (SSF/EPS) testbed being developed and demonstrated at NASA Lewis Research Center. The objectives of the program are to establish artificial intelligence technology paths, to craft knowledge-based tools with advanced human-operator interfaces for power systems, and to interface and integrate knowledge-based systems with conventional controllers. The Autonomous Power EXpert (APEX) portion of the APS program will integrate a knowledge-based fault diagnostic system and a power resource planner-scheduler. Then APEX will interface on-line with the SSF/EPS testbed and its Power Management Controller (PMC). The key tasks include establishing knowledge bases for system diagnostics, fault detection and isolation analysis, on-line information accessing through PMC, enhanced data management, and multiple-level, object-oriented operator displays. The first prototype of the diagnostic expert system for fault detection and isolation has been developed. The knowledge bases and the rule-based model that were developed for the Power Distribution Control Unit subsystem of the SSF/EPS testbed are described. A corresponding troubleshooting technique is also described.

PMU Measurement-Based Intelligent Strategy for Power System Controlled Islanding

Directory of Open Access Journals (Sweden)

Yi Tang

2018-01-01

Full Text Available Controlled islanding is an effective remedy to prevent large-area blackouts in a power system under a critically unstable condition. When and where to separate the power system are the essential issues facing controlled islanding. In this paper, both tasks are studied to ensure higher time efficiency and a better post-splitting restoration effect. A transient stability assessment model based on extreme learning machine (ELM and trajectory fitting (TF is constructed to determine the start-up criterion for controlled islanding. This model works through prompt stability status judgment with ELM and selective result amendment with TF to ensure that the assessment is both efficient and accurate. Moreover, a splitting surface searching algorithm, subject to minimal power disruption, is proposed for determination of the controlled islanding implementing locations. A highlight of this algorithm is a proposed modified electrical distance concept defined by active power magnitude and reactance on transmission lines that realize a computational burden reduction without feasible solution loss. Finally, the simulation results and comparison analysis based on the New England 39-bus test system validates the implementation effects of the proposed controlled islanding strategy.

Robust PID based power system stabiliser: Design and real-time implementation

Energy Technology Data Exchange (ETDEWEB)

Bevrani, Hassan [Department of Electrical and Computer Eng., University of Kurdistan, Sanandaj (Iran, Islamic Republic of); Hiyama, Takashi [Department of Electrical and Computer Eng., Kumamoto University, Kumamoto (Japan); Bevrani, Hossein [Department of Statistics, University of Tabriz, Tabriz (Iran, Islamic Republic of)

2011-02-15

This paper addresses a new robust control strategy to synthesis of robust proportional-integral-derivative (PID) based power system stabilisers (PSS). The PID based PSS design problem is reduced to find an optimal gain vector via an H{infinity} static output feedback control (H{infinity}-SOF) technique, and the solution is easily carried out using a developed iterative linear matrix inequalities algorithm. To illustrate the developed approach, a real-time experiment has been performed for a longitudinal four-machine infinite-bus system using the Analog Power System Simulator at the Research Laboratory of the Kyushu Electric Power Company. The results of the proposed control strategy are compared with full-order H{infinity} and conventional PSS designs. The robust PSS is shown to maintain the robust performance and minimise the effect of disturbances properly. (author)

Agent Based Control of Electric Power Systems with Distributed Generation

DEFF Research Database (Denmark)

Saleem, Arshad

and subsystems that are able to coordinate, communicate, cooperate, adapt to emerging situations and self organize in an intelligent way. At the same time, rapid development in information and and communication technologies (ICT) have brought new opportunities and elucidations. New Technologies and standards...... control strategies. The results have been discussed from case studies of multiagent based distributed control scenarios in electric power systems. The main contribution of this work is a proposal for system design methodology for application of intelligent agent technology in power systems....... Situation in Denmark is even more interesting, with a current 20% penetration of wind energy it is moving towards an ambitious goal of 50% penetration by the year 2050. Realization of these concepts requires that power systems should be of distributed nature { consisting of autonomous components...

Dynamic model based novel findings in power systems analysis and frequency measurement verification

Science.gov (United States)

Kook, Kyung Soo

This study selects several new advanced topics in power systems, and verifies their usefulness using the simulation. In the study on ratio of the equivalent reactance and resistance of the bulk power systems, the simulation results give us the more correct value of X/R of the bulk power system, which can explain why the active power compensation is also important in voltage flicker mitigation. In the application study of the Energy Storage System(ESS) to the wind power, the new model implementation of the ESS connected to the wind power is proposed, and the control effect of ESS to the intermittency of the wind power is verified. Also this study conducts the intensive simulations for clarifying the behavior of the wide-area power system frequency as well as the possibility of the on-line instability detection. In our POWER IT Laboratory, since 2003, the U.S. national frequency monitoring network (FNET) has been being continuously operated to monitor the wide-area power system frequency in the U.S. Using the measured frequency data, the event of the power system is triggered, and its location and scale are estimated. This study also looks for the possibility of using the simulation technologies to contribute the applications of FNET, finds similarity of the event detection orders between the frequency measurements and the simulations in the U.S. Eastern power grid, and develops the new methodology for estimating the event location based on the simulated N-1 contingencies using the frequency measurement. It has been pointed out that the simulation results can not represent the actual response of the power systems due to the inevitable limit of modeling power systems and different operating conditions of the systems at every second. However, in the circumstances that we need to test such an important infrastructure supplying the electric energy without taking any risk of it, the software based simulation will be the best solution to verify the new technologies in

PLL Based Energy Efficient PV System with Fuzzy Logic Based Power Tracker for Smart Grid Applications.

Science.gov (United States)

Rohini, G; Jamuna, V

This work aims at improving the dynamic performance of the available photovoltaic (PV) system and maximizing the power obtained from it by the use of cascaded converters with intelligent control techniques. Fuzzy logic based maximum power point technique is embedded on the first conversion stage to obtain the maximum power from the available PV array. The cascading of second converter is needed to maintain the terminal voltage at grid potential. The soft-switching region of three-stage converter is increased with the proposed phase-locked loop based control strategy. The proposed strategy leads to reduction in the ripple content, rating of components, and switching losses. The PV array is mathematically modeled and the system is simulated and the results are analyzed. The performance of the system is compared with the existing maximum power point tracking algorithms. The authors have endeavored to accomplish maximum power and improved reliability for the same insolation of the PV system. Hardware results of the system are also discussed to prove the validity of the simulation results.

PLL Based Energy Efficient PV System with Fuzzy Logic Based Power Tracker for Smart Grid Applications

Directory of Open Access Journals (Sweden)

G. Rohini

2016-01-01

Full Text Available This work aims at improving the dynamic performance of the available photovoltaic (PV system and maximizing the power obtained from it by the use of cascaded converters with intelligent control techniques. Fuzzy logic based maximum power point technique is embedded on the first conversion stage to obtain the maximum power from the available PV array. The cascading of second converter is needed to maintain the terminal voltage at grid potential. The soft-switching region of three-stage converter is increased with the proposed phase-locked loop based control strategy. The proposed strategy leads to reduction in the ripple content, rating of components, and switching losses. The PV array is mathematically modeled and the system is simulated and the results are analyzed. The performance of the system is compared with the existing maximum power point tracking algorithms. The authors have endeavored to accomplish maximum power and improved reliability for the same insolation of the PV system. Hardware results of the system are also discussed to prove the validity of the simulation results.

Uninterrupted thermoelectric energy harvesting using temperature-sensor-based maximum power point tracking system

International Nuclear Information System (INIS)

Park, Jae-Do; Lee, Hohyun; Bond, Matthew

2014-01-01

Highlights: • Feedforward MPPT scheme for uninterrupted TEG energy harvesting is suggested. • Temperature sensors are used to avoid current measurement or source disconnection. • MPP voltage reference is generated based on OCV vs. temperature differential model. • Optimal operating condition is maintained using hysteresis controller. • Any type of power converter can be used in the proposed scheme. - Abstract: In this paper, a thermoelectric generator (TEG) energy harvesting system with a temperature-sensor-based maximum power point tracking (MPPT) method is presented. Conventional MPPT algorithms for photovoltaic cells may not be suitable for thermoelectric power generation because a significant amount of time is required for TEG systems to reach a steady state. Moreover, complexity and additional power consumption in conventional circuits and periodic disconnection of power source are not desirable for low-power energy harvesting applications. The proposed system can track the varying maximum power point (MPP) with a simple and inexpensive temperature-sensor-based circuit without instantaneous power measurement or TEG disconnection. This system uses TEG’s open circuit voltage (OCV) characteristic with respect to temperature gradient to generate a proper reference voltage signal, i.e., half of the TEG’s OCV. The power converter controller maintains the TEG output voltage at the reference level so that the maximum power can be extracted for the given temperature condition. This feedforward MPPT scheme is inherently stable and can be implemented without any complex microcontroller circuit. The proposed system has been validated analytically and experimentally, and shows a maximum power tracking error of 1.15%

Study on frequency characteristics of wireless power transmission system based on magnetic coupling resonance

Science.gov (United States)

Liang, L. H.; Liu, Z. Z.; Hou, Y. J.; Zeng, H.; Yue, Z. K.; Cui, S.

2017-11-01

In order to study the frequency characteristics of the wireless energy transmission system based on the magnetic coupling resonance, a circuit model based on the magnetic coupling resonant wireless energy transmission system is established. The influence of the load on the frequency characteristics of the wireless power transmission system is analysed. The circuit coupling theory is used to derive the minimum load required to suppress frequency splitting. Simulation and experimental results verify that when the load size is lower than a certain value, the system will appear frequency splitting, increasing the load size can effectively suppress the frequency splitting phenomenon. The power regulation scheme of the wireless charging system based on magnetic coupling resonance is given. This study provides a theoretical basis for load selection and power regulation of wireless power transmission systems.

DC power supplies power management and surge protection for power electronic systems

CERN Document Server

Kularatna, Nihal

2011-01-01

Modern electronic systems, particularly portable consumer electronic systems and processor based systems, are power hungry, compact, and feature packed. This book presents the most essential summaries of the theory behind DC-DC converter topologies of both linear and switching types. The text discusses power supply characteristics and design specifications based on new developments in power management techniques and modern semiconductors entering into the portable electronics market. The author also addresses off-the-line power supplies, digital control of power supply, power supply protection

Identification of Characterization Factor for Power System Oscillation Based on Multiple Synchronized Phasor Measurements

Science.gov (United States)

Hashiguchi, Takuhei; Watanabe, Masayuki; Matsushita, Akihiro; Mitani, Yasunori; Saeki, Osamu; Tsuji, Kiichiro; Hojo, Masahide; Ukai, Hiroyuki

Electric power systems in Japan are composed of remote and distributed location of generators and loads mainly concentrated in large demand areas. The structures having long distance transmission tend to produce heavy power flow with increasing electric power demand. In addition, some independent power producers (IPP) and power producer and suppliers (PPS) are participating in the power generation business, which makes power system dynamics more complex. However, there was little observation as a whole power system. In this paper the authors present a global monitoring system of power system dynamics by using the synchronized phasor measurement of demand side outlets. Phasor Measurement Units (PMU) are synchronized based on the global positioning system (GPS). The purpose of this paper is to show oscillation characteristics and methods for processing original data obtained from PMU after certain power system disturbances triggered by some accidents. This analysis resulted in the observation of the lowest and the second lowest frequency mode. The derivation of eigenvalue with two degree of freedom model brings a monitoring of two oscillation modes. Signal processing based on Wavelet analysis and simulation studies to illustrate the obtained phenomena are demonstrated in detail.

Techno-Economic Evaluation of a Stand-Alone Power System Based on Solar Power/Batteries for Global System for Mobile Communications Base Stations

Directory of Open Access Journals (Sweden)

Mohammed H. Alsharif

2017-03-01

Full Text Available Energy consumption in cellular networks is receiving significant attention from academia and the industry due to its significant potential economic and ecological influence. Energy efficiency and renewable energy are the main pillars of sustainability and environmental compatibility. Technological advancements and cost reduction for photovoltaics are making cellular base stations (BSs; a key source of energy consumption in cellular networks powered by solar energy sources a long-term promising solution for the mobile cellular network industry. This paper addresses issues of deployment and operation of two solar-powered global system for mobile communications (GSM BSs that are being deployed at present (GSM BS 2/2/2 and GSM BS 4/4/4. The study is based on the characteristics of South Korean solar radiation exposure. The optimum criteria as well as economic and technical feasibility for various BSs are analyzed using a hybrid optimization model for electric renewables. In addition, initial capital, replacement, operations, maintenance, and total net present costs for various solar-powered BSs are discussed. Furthermore, the economic feasibility of the proposed solar system is compared with conventional energy sources in urban and remote areas.

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.

DSOGI-PLL Based Power Control Method to Mitigate Control Errors Under Disturbances of Grid Connected Hybrid Renewable Power Systems

Directory of Open Access Journals (Sweden)

Mehmet Emin Meral

2018-01-01

Full Text Available The control of power converter devices is one of the main research lines in interfaced renewable energy sources, such as solar cells and wind turbines. Therefore, suitable control algorithms should be designed in order to regulate power or current properly and attain a good power quality for some disturbances, such as voltage sag/swell, voltage unbalances and fluctuations, long interruptions, and harmonics. Various synchronisation techniques based control strategies are implemented for the hybrid power system applications under unbalanced conditions in literature studies. In this paper, synchronisation algorithms based Proportional-Resonant (PR power/current controller is applied to the hybrid power system (solar cell + wind turbine + grid, and Dual Second Order Generalized Integrator-Phase Locked Loop (DSOGI-PLL based PR controller in stationary reference frame provides a solution to overcome these problems. The influence of various cases, such as unbalance, and harmonic conditions, is examined, analysed and compared to the PR controllers based on DSOGI-PLL and SRF-PLL. The results verify the effectiveness and correctness of the proposed DSOGI-PLL based power control method.

A microprocessor-based power control data acquisition system

International Nuclear Information System (INIS)

Greenberg, S.

1982-10-01

The project reported deals with one of the aspects of power plant control and management. In order to perform optimal distribution of power and load switching, one has to solve a specific optimization problem. In order to solve this problem one needs to collect current and power expenditure data from a large number of channels and have them processed. This particular procedure is defined as data acquisition and it constitutes the main topic of this project. A microprocessor-based data acquisition system for power management is investigated and developed. The current and power data of about 100 analog channels are sampled and collected in real-time. These data are subsequently processed to calculate the power factor (cos phi) for each channel and the maximum demand. The data is processed by an AMD 9511 Arithmetic Processing Unit and the whole system is controlled by an Intel 8080A CPU. All this information is then transfered to a universal computer through a synchronized communication channel. The optimization computations would be performed by the high level computer. Different ways of performing the search of data over a large number of channels have been investigated. A particular solution to overcome the gain and offset drift of the A/D converter, using software, has been proposed. The 8080A supervises the collection and routing of data in real time, while the 9511 performs calculation, using these data. (Author)

Development of a component centered fault monitoring and diagnosis knowledge based system for space power system

Science.gov (United States)

Lee, S. C.; Lollar, Louis F.

1988-01-01

The overall approach currently being taken in the development of AMPERES (Autonomously Managed Power System Extendable Real-time Expert System), a knowledge-based expert system for fault monitoring and diagnosis of space power systems, is discussed. The system architecture, knowledge representation, and fault monitoring and diagnosis strategy are examined. A 'component-centered' approach developed in this project is described. Critical issues requiring further study are identified.

Grid-friendly wind power systems based on the synchronverter technology

International Nuclear Information System (INIS)

Zhong, Qing-Chang; Ma, Zhenyu; Ming, Wen-Long; Konstantopoulos, George C.

2015-01-01

Highlights: • A grid-friendly wind power system that uses the synchronverter technology is proposed. • Both the rotor-side and the grid-side converters act as synchronverters. • The complete generator–motor–generator system improves the performance under grid faults. • Real-time digital simulation results verify the effectiveness of the proposed method. - Abstract: Back-to-back PWM converters are becoming a realistic alternative to conventional converters in high-power wind power applications. In this paper, a control strategy based on the synchronverter technology is proposed for back-to-back PWM converters. Both converters are run as synchronverters, which are mathematically equivalent to the conventional synchronous generators. The rotor-side converter is responsible for maintaining the DC link voltage and the grid-side converter is responsible for the maximum power point tracking (MPPT). As the two converters are operated using the synchronverter technology, the formed wind power system becomes more friendly to the grid. Extensive real-time digital simulation results are presented to verify the effectiveness of the proposed method under normal operation and grid-fault scenarios

Distributed, price-based control approach to market-based operation of future power systems

NARCIS (Netherlands)

Jokic, A.; Bosch, van den P.P.J.; Hermans, R.M.

2009-01-01

In this paper we present, discuss and illustrate on examples the price-based control paradigm as a suitable approach to solve some of the challenging problems facing future, market-based power systems. It is illustrated how global objectives and constraints are optimally translated into time-varying

Performance Analyses of Renewable and Fuel Power Supply Systems for Different Base Station Sites

Directory of Open Access Journals (Sweden)

Josip Lorincz

2014-11-01

Full Text Available Base station sites (BSSs powered with renewable energy sources have gained the attention of cellular operators during the last few years. This is because such “green” BSSs impose significant reductions in the operational expenditures (OPEX of telecom operators due to the possibility of on-site renewable energy harvesting. In this paper, the green BSSs power supply system parameters detected through remote and centralized real time sensing are presented. An implemented sensing system based on a wireless sensor network enables reliable collection and post-processing analyses of many parameters, such as: total charging/discharging current of power supply system, battery voltage and temperature, wind speed, etc. As an example, yearly sensing results for three different BSS configurations powered by solar and/or wind energy are discussed in terms of renewable energy supply (RES system performance. In the case of powering those BSS with standalone systems based on a fuel generator, the fuel consumption models expressing interdependence among the generator load and fuel consumption are proposed. This has allowed energy-efficiency comparison of the fuel powered and RES systems, which is presented in terms of the OPEX and carbon dioxide (CO2 reductions. Additionally, approaches based on different BSS air-conditioning systems and the on/off regulation of a daily fuel generator activity are proposed and validated in terms of energy and capital expenditure (CAPEX savings.

Integrated multiscale simulation of combined heat and power based district heating system

International Nuclear Information System (INIS)

Li, Peifeng; Nord, Natasa; Ertesvåg, Ivar Ståle; Ge, Zhihua; Yang, Zhiping; Yang, Yongping

2015-01-01

Highlights: • Simulation of power plant, district heating network and heat users in detail and integrated. • Coupled calculation and analysis of the heat and pressure losses of the district heating network. • District heating is not preferable for very low heat load due to relatively high heat loss. • Lower design supply temperatures of the district heating network give higher system efficiency. - Abstract: Many studies have been carried out separately on combined heat and power and district heating. However, little work has been done considering the heat source, the district heating network and the heat users simultaneously, especially when it comes to the heating system with large-scale combined heat and power plant. For the purpose of energy conservation, it is very important to know well the system performance of the integrated heating system from the very primary fuel input to the terminal heat users. This paper set up a model of 300 MW electric power rated air-cooled combined heat and power plant using Ebsilon software, which was validated according to the design data from the turbine manufacturer. Then, the model of heating network and heat users were developed based on the fundamental theories of fluid mechanics and heat transfer. Finally the combined heat and power based district heating system was obtained and the system performances within multiscale scope of the system were analyzed using the developed Ebsilon model. Topics with regard to the heat loss, the pressure drop, the pump power consumption and the supply temperatures of the district heating network were discussed. Besides, the operational issues of the integrated system were also researched. Several useful conclusions were drawn. It was found that a lower design primary supply temperature of the district heating network would give a higher seasonal energy efficiency of the integrated system throughout the whole heating season. Moreover, it was not always right to relate low design

A modular Space Station/Base electrical power system - Requirements and design study.

Science.gov (United States)

Eliason, J. T.; Adkisson, W. B.

1972-01-01

The requirements and procedures necessary for definition and specification of an electrical power system (EPS) for the future space station are discussed herein. The considered space station EPS consists of a replaceable main power module with self-contained auxiliary power, guidance, control, and communication subsystems. This independent power source may 'plug into' a space station module which has its own electrical distribution, control, power conditioning, and auxiliary power subsystems. Integration problems are discussed, and a transmission system selected with local floor-by-floor power conditioning and distribution in the station module. This technique eliminates the need for an immediate long range decision on the ultimate space base power sources by providing capability for almost any currently considered option.

Fuzzy Controller for a Voltage-Regulated Solar-Powered MPPT System for Hybrid Power System Applications

Directory of Open Access Journals (Sweden)

Jaw-Kuen Shiau

2015-04-01

Full Text Available This paper presents the design of a fuzzy-logic-based voltage-regulated solar power maximum power point tracking (MPPT system for applications involving hybrid power systems. The system contains a solar power system and battery as the primary and secondary power sources, respectively. The solar system alone supplies power to the electric motor and maintains the output voltage at a predetermined level when it has sufficient power. When the solar power is insufficient, the solar system is operated at its maximum power point (MPP and the battery is engaged to compensate for the insufficiency. First, a variant of the incremental conductance MPP condition was established. Under the MPP condition, the voltage-regulated MPPT system was formulated as a feedback control system, where the MPP condition and voltage regulation requirements were used as the system inputs. Next, a fuzzy controller was developed to perform the voltage-regulated MPPT function for the hybrid power system. A simulation model based on Matrix laboratory (MATLAB/SIMULINK (a block diagram environment for multi-domain simulation and model-based design and a piecewise linear electric circuit simulation (PLECS tool for controlling the dc motor velocity was developed to verify the voltage-regulated solar power MPPT system.

Optimizing MEMS-Based Storage Devices for Mobile Battery-Powered Systems

NARCIS (Netherlands)

Khatib, M.G.; Hartel, Pieter H.

An emerging storage technology, called MEMS-based storage, promises nonvolatile storage devices with ultrahigh density, high rigidity, a small form factor, and low cost. For these reasons, MEMS-based storage devices are suitable for battery-powered mobile systems such as PDAs. For deployment in such

The fault monitoring and diagnosis knowledge-based system for space power systems: AMPERES, phase 1

Science.gov (United States)

Lee, S. C.

1989-01-01

The objective is to develop a real time fault monitoring and diagnosis knowledge-based system (KBS) for space power systems which can save costly operational manpower and can achieve more reliable space power system operation. The proposed KBS was developed using the Autonomously Managed Power System (AMPS) test facility currently installed at NASA Marshall Space Flight Center (MSFC), but the basic approach taken for this project could be applicable for other space power systems. The proposed KBS is entitled Autonomously Managed Power-System Extendible Real-time Expert System (AMPERES). In Phase 1 the emphasis was put on the design of the overall KBS, the identification of the basic research required, the initial performance of the research, and the development of a prototype KBS. In Phase 2, emphasis is put on the completion of the research initiated in Phase 1, and the enhancement of the prototype KBS developed in Phase 1. This enhancement is intended to achieve a working real time KBS incorporated with the NASA space power system test facilities. Three major research areas were identified and progress was made in each area. These areas are real time data acquisition and its supporting data structure; sensor value validations; development of inference scheme for effective fault monitoring and diagnosis, and its supporting knowledge representation scheme.

Emergy-based sustainability evaluation of wind power generation systems

International Nuclear Information System (INIS)

Yang, Jin; Chen, Bin

2016-01-01

Highlights: • Emergy is used to quantify the sustainability level of wind farms. • A GHG-based indicator is incorporated into emergetic accounting. • Possible pathways to achieve sustainable wind farm management are analyzed. - Abstract: With large-scale commercialization of wind technology, one must investigate economical and sustainable wind resource utilization. In this paper, emergy analysis is used to quantify the environmental pressure, renewability, economic efficiency, and sustainability of a typical wind power system, considering the lifetime stages from extraction and processing of raw materials and resources to the final product (electricity) via material transportation, construction and operation. Possible pathways to achieve sustainable management of wind energy supply chain were also analyzed based on scenario analysis. Results show that wind power is a promising means of substituting traditional fossil fuel-based power generation systems, with the lowest transformity of 4.49 × 10"4 sej/J, smaller environmental loading ratio of 5.84, and lower greenhouse gas emission intensity of 0.56 kg/kWh. To shed light on potential pathways to achieve sustainable and low-carbon wind energy supply chain management and make informed choices, a sensitivity analysis was done by establishing scenarios from the perspectives of material recycling and technical development. Results suggest that using new materials of lower energy intensity or recycled materials in upstream wind turbine manufacturing and construction materials are the most effective measures.

A GIS-based Power Transmission Management Information System

Institute of Scientific and Technical Information of China (English)

2010-01-01

<正>Based on analyzing the shortcomings of electric power enterprise in traditional operation pattern,this paper combines components GIS with the application of management information system,and uses the structure which unifies three layers C/S and B/S.Also,proposed using the GPS intellectualization patrol.This may be useful to guarantees the transmission line’s operation to be safe and stable.

Chaotic improved PSO-based multi-objective optimization for minimization of power losses and L index in power systems

International Nuclear Information System (INIS)

Chen, Gonggui; Liu, Lilan; Song, Peizhu; Du, Yangwei

2014-01-01

Highlights: • New method for MOORPD problem using MOCIPSO and MOIPSO approaches. • Constrain-prior Pareto-dominance method is proposed to meet the constraints. • The limits of the apparent power flow of transmission line are considered. • MOORPD model is built up for MOORPD problem. • The achieved results by MOCIPSO and MOIPSO approaches are better than MOPSO method. - Abstract: Multi-objective optimal reactive power dispatch (MOORPD) seeks to not only minimize power losses, but also improve the stability of power system simultaneously. In this paper, the static voltage stability enhancement is achieved through incorporating L index in MOORPD problem. Chaotic improved PSO-based multi-objective optimization (MOCIPSO) and improved PSO-based multi-objective optimization (MOIPSO) approaches are proposed for solving complex multi-objective, mixed integer nonlinear problems such as minimization of power losses and L index in power systems simultaneously. In MOCIPSO and MOIPSO based optimization approaches, crossover operator is proposed to enhance PSO diversity and improve their global searching capability, and for MOCIPSO based optimization approach, chaotic sequences based on logistic map instead of random sequences is introduced to PSO for enhancing exploitation capability. In the two approaches, constrain-prior Pareto-dominance method (CPM) is proposed to meet the inequality constraints on state variables, the sorting and crowding distance methods are considered to maintain a well distributed Pareto optimal solutions, and moreover, fuzzy set theory is employed to extract the best compromise solution over the Pareto optimal curve. The proposed approaches have been examined and tested in the IEEE 30 bus and the IEEE 57 bus power systems. The performances of MOCIPSO, MOIPSO, and multi-objective PSO (MOPSO) approaches are compared with respect to multi-objective performance measures. The simulation results are promising and confirm the ability of MOCIPSO and

Laser-powered lunar base

International Nuclear Information System (INIS)

Costen, R.; Humes, D.H.; Walker, G.H.; Williams, M.D.; Deyoung, R.J.

1989-01-01

The objective was to compare a nuclear reactor-driven Sterling engine lunar base power source to a laser-to-electric converter with orbiting laser power station, each providing 1 MW of electricity to the lunar base. The comparison was made on the basis of total mass required in low-Earth-orbit for each system. This total mass includes transportation mass required to place systems in low-lunar orbit or on the lunar surface. The nuclear reactor with Sterling engines is considered the reference mission for lunar base power and is described first. The details of the laser-to-electric converter and mass are discussed. The next two solar-driven high-power laser concepts, the diode array laser or the iodine laser system, are discussed with associated masses in low-lunar-orbit. Finally, the payoff for laser-power beaming is summarized

ANFIS based UPFC supplementary controller for damping low frequency oscillations in power systems

Directory of Open Access Journals (Sweden)

M. Sobha

2007-12-01

Full Text Available An adaptive neuro- fuzzy inference system (ANFIS based supplementary Unified Power Flow Controller (UPFC to superimpose the damping function on the control signal of UPFC is proposed. By using a hybrid learning procedure, the proposed ANFIS construct an input –output mapping based on stipulated input-output data pairs. The linguistic rules, considering the dependence of the plant output on the controlling signal are used to build the initial fuzzy inference structure. On the basis of linearized Philips-Hefron model of power system installed with UPFC, the damping function of the UPFC with various alternative UPFC control signals are investigated. In the simulations under widely varying operating conditions and system parameters, ANFIS based controller yields improved performance when compared with constant gain controller, based on phase compensation technique. To validate the robustness of the proposed technique, the approach is integrated to a multi-machine power system and the nonlinear simulation results are presented

Power System Transient Diagnostics Based on Novel Traveling Wave Detection

Science.gov (United States)

Hamidi, Reza Jalilzadeh

Modern electrical power systems demand novel diagnostic approaches to enhancing the system resiliency by improving the state-of-the-art algorithms. The proliferation of high-voltage optical transducers and high time-resolution measurements provide opportunities to develop novel diagnostic methods of very fast transients in power systems. At the same time, emerging complex configuration, such as multi-terminal hybrid transmission systems, limits the applications of the traditional diagnostic methods, especially in fault location and health monitoring. The impedance-based fault-location methods are inefficient for cross-bounded cables, which are widely used for connection of offshore wind farms to the main grid. Thus, this dissertation first presents a novel traveling wave-based fault-location method for hybrid multi-terminal transmission systems. The proposed method utilizes time-synchronized high-sampling voltage measurements. The traveling wave arrival times (ATs) are detected by observation of the squares of wavelet transformation coefficients. Using the ATs, an over-determined set of linear equations are developed for noise reduction, and consequently, the faulty segment is determined based on the characteristics of the provided equation set. Then, the fault location is estimated. The accuracy and capabilities of the proposed fault location method are evaluated and also compared to the existing traveling-wave-based method for a wide range of fault parameters. In order to improve power systems stability, auto-reclosing (AR), single-phase auto-reclosing (SPAR), and adaptive single-phase auto-reclosing (ASPAR) methods have been developed with the final objectives of distinguishing between the transient and permanent faults to clear the transient faults without de-energization of the solid phases. However, the features of the electrical arcs (transient faults) are severely influenced by a number of random parameters, including the convection of the air and plasma

Model based PI power system stabilizer design for damping low frequency oscillations in power systems.

Science.gov (United States)

Salgotra, Aprajita; Pan, Somnath

2018-05-01

This paper explores a two-level control strategy by blending local controller with centralized controller for the low frequency oscillations in a power system. The proposed control scheme provides stabilization of local modes using a local controller and minimizes the effect of inter-connection of sub-systems performance through a centralized control. For designing the local controllers in the form of proportional-integral power system stabilizer (PI-PSS), a simple and straight forward frequency domain direct synthesis method is considered that works on use of a suitable reference model which is based on the desired requirements. Several examples both on one machine infinite bus and multi-machine systems taken from the literature are illustrated to show the efficacy of the proposed PI-PSS. The effective damping of the systems is found to be increased remarkably which is reflected in the time-responses; even unstable operation has been stabilized with improved damping after applying the proposed controller. The proposed controllers give remarkable improvement in damping the oscillations in all the illustrations considered here and as for example, the value of damping factor has been increased from 0.0217 to 0.666 in Example 1. The simulation results obtained by the proposed control strategy are favourably compared with some controllers prevalent in the literature. Copyright © 2018 ISA. Published by Elsevier Ltd. All rights reserved.

Maximum power point tracking for photovoltaic solar pump based on ANFIS tuning system

Directory of Open Access Journals (Sweden)

S. Shabaan

2018-05-01

Full Text Available Solar photovoltaic (PV systems are a clean and naturally replenished energy source. PV panels have a unique point which represents the maximum available power and this point depend on the environmental conditions such as temperature and irradiance. A maximum power point tracking (MPPT is therefore necessary for maximum efficiency. In this paper, a study of MPPT for PV water pumping system based on adaptive neuro-fuzzy inference system (ANFIS is discussed. A comparison between the performance of the system with and without MPPT is carried out under varying irradiation and temperature conditions. ANFIS based controller shows fast response with high efficiency at all irradiance and temperature levels making it a powerful technique for non-linear systems as PV modules. Keywords: MPPT, ANFIS, Boost converter, PMDC pump

Hybrid Automaton Based Controller Design for Damage Mitigation of Islanded Power Systems

Science.gov (United States)

Lahiri, Sudipta

some of these limitations, we derive a hybrid automaton model of a power system as a Discrete Event System (DES) plant and controller. The DES plant consists of a switched continuous system with an interface. The system state space is categorized based on safety criteria and discrete control specifications are embedded as transition rules within the DES controller. The DES controller searches for feasible control policies that drive the system trajectories from unsafe states to safe states. We define metrics to quantify the performance of these policies, thus allowing the derivation of the most suitable policy for a set of design specifications and disturbance type. Applications in voltage control, frequency control and dynamic service restoration is presented on a benchmark power system with approximately forty continuous states and eighteen thousand discrete states. To enable the analysis, we build a computational framework based on efficient symbolic computation tools in Mathematica and numerical integration tools in Matlab / Simulink so that the methodology can be replicated for a wide variety of applications. The framework is quite general, and may be expanded to problems beyond power systems.

Engineering design and exergy analyses for combustion gas turbine based power generation system

International Nuclear Information System (INIS)

Sue, D.-C.; Chuang, C.-C.

2004-01-01

This paper presents the engineering design and theoretical exergetic analyses of the plant for combustion gas turbine based power generation systems. Exergy analysis is performed based on the first and second laws of thermodynamics for power generation systems. The results show the exergy analyses for a steam cycle system predict the plant efficiency more precisely. The plant efficiency for partial load operation is lower than full load operation. Increasing the pinch points will decrease the combined cycle plant efficiency. The engineering design is based on inlet air-cooling and natural gas preheating for increasing the net power output and efficiency. To evaluate the energy utilization, one combined cycle unit and one cogeneration system, consisting of gas turbine generators, heat recovery steam generators, one steam turbine generator with steam extracted for process have been analyzed. The analytical results are used for engineering design and component selection

Agent-based power sharing scheme for active hybrid power sources

Science.gov (United States)

Jiang, Zhenhua

The active hybridization technique provides an effective approach to combining the best properties of a heterogeneous set of power sources to achieve higher energy density, power density and fuel efficiency. Active hybrid power sources can be used to power hybrid electric vehicles with selected combinations of internal combustion engines, fuel cells, batteries, and/or supercapacitors. They can be deployed in all-electric ships to build a distributed electric power system. They can also be used in a bulk power system to construct an autonomous distributed energy system. An important aspect in designing an active hybrid power source is to find a suitable control strategy that can manage the active power sharing and take advantage of the inherent scalability and robustness benefits of the hybrid system. This paper presents an agent-based power sharing scheme for active hybrid power sources. To demonstrate the effectiveness of the proposed agent-based power sharing scheme, simulation studies are performed for a hybrid power source that can be used in a solar car as the main propulsion power module. Simulation results clearly indicate that the agent-based control framework is effective to coordinate the various energy sources and manage the power/voltage profiles.

Converters for Distributed Power Generation Systems

DEFF Research Database (Denmark)

Blaabjerg, Frede; Yang, Yongheng

2015-01-01

Power electronics technology has become the enabling technology for the integration of distributed power generation systems (DPGS) such as offshore wind turbine power systems and commercial photovoltaic power plants. Depending on the applications, a vast array of DPGS-based power converter...... topologies has been developed and more are coming into the market in order to achieve an efficient and reliable power conversion from the renewables. In addition, stringent demands from both the distribution system operators and the consumers have been imposed on the renewable-based DPGS. This article...... presents an overview of the power converters for the DPGS, mainly based on wind turbine systems and photovoltaic systems, covering a wide range of applications. Moreover, the modulation schemes and interfacing power filters for the power converters are also exemplified. Finally, the general control...

Reference Concepts for a Space-Based Hydrogen-Oxygen Combustion, Turboalternator, Burst Power System

National Research Council Canada - National Science Library

Edenburn, Michael

1990-01-01

This report describes reference concepts for a hydrogen-oxygen combustion, turboalternator power system that supplies power during battle engagement to a space-based, ballistic missile defense platform...

Computer-based systems for nuclear power stations

International Nuclear Information System (INIS)

Humble, P.J.; Welbourne, D.; Belcher, G.

1995-01-01

The published intentions of vendors are for extensive touch-screen control and computer-based protection. The software features needed for acceptance in the UK are indicated. The defence in depth needed is analyzed. Current practice in aircraft flight control systems and the software methods available are discussed. Software partitioning and mathematically formal methods are appropriate for the structures and simple logic needed for nuclear power applications. The potential for claims of diversity and independence between two computer-based subsystems of a protection system is discussed. Features needed to meet a single failure criterion applied to software are discussed. Conclusions are given on the main factors which a design should allow for. The work reported was done for the Health and Safety Executive of the UK (HSE), and acknowledgement is given to them, to NNC Ltd and to GEC-Marconi Avionics Ltd for permission to publish. The opinions and recommendations expressed are those of the authors and do not necessarily reflect those of HSE. (Author)

Multi-Stage Optimization-Based Automatic Voltage Control Systems Considering Wind Power Forecasting Errors

DEFF Research Database (Denmark)

Qin, Nan; Bak, Claus Leth; Abildgaard, Hans

2017-01-01

This paper proposes an automatic voltage control (AVC) system for power systems with limited continuous voltage control capability. The objective is to minimize the operational cost over a period, which consists of the power loss in the grid, the shunt switching cost, the transformer tap change...... electricity control center, where study cases based on the western Danish power system demonstrate the superiority of the proposed AVC system in term of the cost minimization. Monte Carlo simulations are carried out to verify the proposed method on the robustness improvements....

Space-based solar power conversion and delivery systems study. Volume 2: Engineering analysis of orbital systems

Science.gov (United States)

1976-01-01

Program plans, schedules, and costs are determined for a synchronous orbit-based power generation and relay system. Requirements for the satellite solar power station (SSPS) and the power relay satellite (PRS) are explored. Engineering analysis of large solar arrays, flight mechanics and control, transportation, assembly and maintenance, and microwave transmission are included.

Design of Mobile Operation and Maintenance System Based on Power GIS and GPS

Directory of Open Access Journals (Sweden)

Jing TAO

2017-01-01

Full Text Available In order to solve the low efficiency of operation and maintenance and the problems of management coordination caused by the coexistence of off-line operation and maintenance and multi system coexistence in current power telecommunication operation and maintenance, this paper proposes a mobile operation and maintenance system based on power GIS and GPS location technology. The system is based on the C/S architecture, and the mobile operation and maintenance terminal is connected with the operation and maintenance management terminal through wireless and wired network. In addition to meeting basic business requirements, the system integrates power GIS functions to visually demonstrate communication resources, personnel, and failures. The staff can use the wireless mobile terminal which integrated GPS module for to operate and maintain, and can locate accurately in real time.

Analysis of fixed tilt and sun tracking photovoltaic–micro wind based hybrid power systems

International Nuclear Information System (INIS)

Sinha, Sunanda; Chandel, S.S.

2016-01-01

Graphical abstract: 6 kW_p photovoltaic–micro wind based hybrid power system analysis in a Indian Western Himalayan location. - Highlights: • Power generation by a roof mounted photovoltaic–micro wind hybrid system is explored. • Optimum hybrid configurations using fixed and sun tracking photovoltaic systems are determined. • Analysis of hybrid systems with optimally tilted and different sun tracking systems is presented. • Two axis sun tracking systems are found to generate 4.88–26.29% more energy than fixed tilt system. • Hybrid system installed at optimum tilt angle is found to be cost effective than a sun tracking system. - Abstract: In this study fixed tilt and sun tracking photovoltaic based micro wind hybrid power systems are analyzed along with determining the optimum configurations for a 6 kW_p roof mounted micro wind based hybrid system using fixed and tracking photovoltaic systems to enhance the power generation potential in a low windy Indian hilly terrain with good solar resource. The main objective of the study is to enhance power generation by focusing on photovoltaic component of the hybrid system. A comparative power generation analysis of different configurations of hybrid systems with fixed tilt, monthly optimum tilt, yearly optimum tilt and 6 different sun tracking photovoltaic systems is carried out using Hybrid Optimization Model for Electric Renewables. Monthly and seasonal optimum tilt angles determined for the location vary between 0° and 60° with annual optimum tilt angle as 29.25°. The optimum configurations for all sun tracking systems except for the two axis tracking system is found to be 7 kW_p photovoltaic system, one 5 kW_p wind turbine, 10 batteries and a 2 kW_p inverter. The optimum configuration for two axis tracking system and two types of fixed tilt systems, is found to be a 8 kW_p photovoltaic system, one 5 kW_p wind turbine, 10 batteries and a 2 kW_p inverter. The results show that horizontal axis with

Price-based control of electrical power systems

NARCIS (Netherlands)

Jokic, A.; Lazar, M.; Bosch, van den P.P.J.; Negenborn, R.R.; Lukszo, Z.; Hellendorn, H.

2010-01-01

In this chapter we present the price-based control as a suitable approach to solve some of the challenging problems facing future, market-based power sys tems. On the example of economically optimal power balance and transmission network congestion control, we present how global objectives and

Knowledge-based operation guidance system for nuclear power plants based on generic task methodology

International Nuclear Information System (INIS)

Yamada, Naoyuki; Chandrasekaran, B.; Bhatnager, R.

1989-01-01

A knowledge-based system for operation guidance of nuclear power plants is proposed. The Dynamic Procedure Management System (DPMS) is designed and developed to assist human operators interactively by selecting and modifying predefined operation procedures in a dynamic situation. Unlike most operation guidance systems, DPMS has been built based on Generic Task Methodology, which makes the overall framework of the system perspicuous and also lets domain knowledge be represented in a natural way. This paper describes the organization of the system, the definition of each task, and the form and organization of knowledge, followed by an application example. (author)

Construction of APR1000 nuclear power information management system based on international standards

International Nuclear Information System (INIS)

Choi, Seung Hwan; Song, Deok Yong; Han, Byung Sub; An, Kyung Ik; Hwang, Jin Sang

2010-01-01

In recent years, due to speedy rise of international oil prices, orders of nuclear power plant construction have been in progress by many countries to solve the stable supply of power. Our country has continued to perform nuclear power construction. As only a few developed countries like Japan and European countries have its own nuclear power construction technology, competition among them is keen. Our country has awarded the contract of UAE nuclear power plants based on the accumulated nuclear power plant construction technologies so far. In this regard, KEPCO has recognized the needs of information management system to manage nuclear power information and proceeded the implementation of nuclear power information management system for export-model

Construction of APR1000 nuclear power information management system based on international standards

Energy Technology Data Exchange (ETDEWEB)

Choi, Seung Hwan [Korea Electric Power Research Institute, Daejeon (Korea, Republic of); Song, Deok Yong; Han, Byung Sub [Enesys Co., Daejeon (Korea, Republic of); An, Kyung Ik; Hwang, Jin Sang [PartDB Co., Daejeon (Korea, Republic of)

2010-10-15

In recent years, due to speedy rise of international oil prices, orders of nuclear power plant construction have been in progress by many countries to solve the stable supply of power. Our country has continued to perform nuclear power construction. As only a few developed countries like Japan and European countries have its own nuclear power construction technology, competition among them is keen. Our country has awarded the contract of UAE nuclear power plants based on the accumulated nuclear power plant construction technologies so far. In this regard, KEPCO has recognized the needs of information management system to manage nuclear power information and proceeded the implementation of nuclear power information management system for export-model

Nuclear reactor power control system based on flexibility model

International Nuclear Information System (INIS)

Li Gang; Zhao Fuyu; Li Chong; Tai Yun

2011-01-01

Design the nuclear reactor power control system in this paper to cater to a nonlinear nuclear reactor. First, calculate linear power models at five power levels of the reactor as five local models and design controllers of the local models as local controllers. Every local controller consists of an optimal controller contrived by the toolbox of Optimal Controller Designer (OCD) and a proportion-integration-differentiation (PID) controller devised via Genetic Algorithm (GA) to set parameters of the PID controller. According to the local models and controllers, apply the principle of flexibility model developed in the paper to obtain the flexibility model and the flexibility controller at every power level. Second, the flexibility model and the flexibility controller at a level structure the power control system of this level. The set of the whole power control systems corresponding to global power levels is to approximately carry out the power control of the reactor. Finally, the nuclear reactor power control system is simulated. The simulation result shows that the idea of flexibility model is feasible and the nuclear reactor power control system is effective. (author)

Power System Real-Time Monitoring by Using PMU-Based Robust State Estimation Method

DEFF Research Database (Denmark)

Zhao, Junbo; Zhang, Gexiang; Das, Kaushik

2016-01-01

Accurate real-time states provided by the state estimator are critical for power system reliable operation and control. This paper proposes a novel phasor measurement unit (PMU)-based robust state estimation method (PRSEM) to real-time monitor a power system under different operation conditions...... the system real-time states with good robustness and can address several kinds of BD.......-based bad data (BD) detection method, which can handle the smearing effect and critical measurement errors, is presented. We evaluate PRSEM by using IEEE benchmark test systems and a realistic utility system. The numerical results indicate that, in short computation time, PRSEM can effectively track...

Multi-Agent System Based Special Protection and Emergency Control Scheme against Cascading Events in Power System

DEFF Research Database (Denmark)

Liu, Zhou

relay operations due to low voltage or overload state in the post stage of N-1 (or N-k) contingency. If such state could be sensed and adjusted appropriately before those relay actions, the system stability might be sustained. So it is of great significance to develop a suitable protection scheme...... the proposed protection strategy in this thesis, a real time simulation platform based on Real Time Digital Simulator (RTDS) and LabVIEW is built. In this platform, the cases of cascaded blackouts are simulated on the test system simplified from the East Denmark power system. For the MAS based control system......, the distributed power system agents are set up in RTDS, while the agents in higher level are designed by LabVIEW toolkits. The case studies and simulation results demonstrate the effectiveness of real time application of the proposed MAS based special protection and emergency control scheme against the cascaded...

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...

Power Electronic Systems for Switched Reluctance Generator based Wind Farms and DC Networks

DEFF Research Database (Denmark)

Park, Kiwoo

enable various renewable energy sources, such as Photovoltaic (PV) and wind, to produce dc power directly. In addition, battery-based energy storage systems inherently operate with dc power. Hence, dc network (dc-grid) systems which connect these dc sources and storages directly using dc networks...... are gaining much attention again. The dc network system has a great potential to outdo the traditional ac systems in many technical challenges and could be highly profitable especially for offshore wind farm applications, where the size and weight of the components are crucial to the entire system costs......Wind power technology, as the most competitive renewable energy technology, is quickly developing. The wind turbine size is growing and the grid penetration of wind power is increasing rapidly. Recently, the developments on wind power technology pay more attentions on efficiency and reliability...

A New Remote Monitoring System Application in Laser Power Based on LabVIEW

Directory of Open Access Journals (Sweden)

Liu Gaoqiang

2016-01-01

Full Text Available In this paper, a new remote monitoring system based on LabVIEW was proposed to measure laser power automatically and remotely. This system consists of four basic components: an DH-JG2 optical power meter, a NI-USB 6008 data acquisition card, a personal computer (PC, and HP laserJet 1020 Plus printer. Since power output of laser is generally so unstable that abnormal work situation could not retroaction to inspectors right away, new system was designed to solve this problem. The detection system realized function of remote control by TCP protocol and mobile phone. Laser power curve that is measured by detection system demonstrated that the design has a good performance in real-time detection and operability.

GaN-Based Laser Wireless Power Transfer System

Directory of Open Access Journals (Sweden)

Carlo De Santi

2018-01-01

Full Text Available The aim of this work is to present a potential application of gallium nitride-based optoelectronic devices. By using a laser diode and a photodetector, we designed and demonstrated a free-space compact and lightweight wireless power transfer system, whose efficiency is limited by the efficiency of the receiver. We analyzed the effect of the electrical load, temperature, partial absorption and optical excitation distribution on the efficiency, by identifying heating and band-filling as the most impactful processes. By comparing the final demonstrator with a commercial RF-based Qi system, we conclude that the efficiency is still low at close range, but is promising in medium to long range applications. Efficiency may not be a limiting factor, since this concept can enable entirely new possibilities and designs, especially relevant for space applications.

Active Splitting in Longitudinal Power Systems based on a WAMPC

Directory of Open Access Journals (Sweden)

Felipe Arraño-Vargas

2017-12-01

Full Text Available This paper proposes an active splitting scheme especially suitable for longitudinal power systems (LPS. The proposed scheme is based on a modified out-of-step (OOS algorithm combined with an angle difference method using synchrophasor measurements. The remedial actions are based on the detection of possible loss of synchronism due to severe disturbances. The scheme was tested on a detailed dynamic model of the Central Interconnected System of Chile, a good example of extreme LPS. Obtained results show that remedial actions taken by the proposed protection scheme are able to avoid the total collapse of the system during critical contingencies.

Design and optimization of resonance-based efficient wireless power delivery systems for biomedical implants.

Science.gov (United States)

Ramrakhyani, A K; Mirabbasi, S; Mu Chiao

2011-02-01

Resonance-based wireless power delivery is an efficient technique to transfer power over a relatively long distance. This technique typically uses four coils as opposed to two coils used in conventional inductive links. In the four-coil system, the adverse effects of a low coupling coefficient between primary and secondary coils are compensated by using high-quality (Q) factor coils, and the efficiency of the system is improved. Unlike its two-coil counterpart, the efficiency profile of the power transfer is not a monotonically decreasing function of the operating distance and is less sensitive to changes in the distance between the primary and secondary coils. A four-coil energy transfer system can be optimized to provide maximum efficiency at a given operating distance. We have analyzed the four-coil energy transfer systems and outlined the effect of design parameters on power-transfer efficiency. Design steps to obtain the efficient power-transfer system are presented and a design example is provided. A proof-of-concept prototype system is implemented and confirms the validity of the proposed analysis and design techniques. In the prototype system, for a power-link frequency of 700 kHz and a coil distance range of 10 to 20 mm, using a 22-mm diameter implantable coil resonance-based system shows a power-transfer efficiency of more than 80% with an enhanced operating range compared to ~40% efficiency achieved by a conventional two-coil system.

Power system stabilizers based on distributed energy resources for damping of inter-area oscillations

Directory of Open Access Journals (Sweden)

Stefanov Predrag Č.

2014-01-01

Full Text Available This paper deals with inter-area power oscillations damping enhancement by distributed energy resources contained in typical micro grid. Main idea behind this work is to use distributed generation and distributed storage, such as battery energy storage to mimic conventional power system stabilizer, but with regulating active power output, rather than reactive power, as in standard power system stabilizer realization. The analysis of the small signal stability is established for four-machine, two-area system, with inverter based micro grids in each area. Dynamic simulation results are included in this work and they show that proposed controller provides additional damping effect to this test system.

H∞ Excitation Control Design for Stochastic Power Systems with Input Delay Based on Nonlinear Hamiltonian System Theory

Directory of Open Access Journals (Sweden)

Weiwei Sun

2015-01-01

Full Text Available This paper presents H∞ excitation control design problem for power systems with input time delay and disturbances by using nonlinear Hamiltonian system theory. The impact of time delays introduced by remote signal transmission and processing in wide-area measurement system (WAMS is well considered. Meanwhile, the systems under investigation are disturbed by random fluctuation. First, under prefeedback technique, the power systems are described as a nonlinear Hamiltonian system. Then the H∞ excitation controller of generators connected to distant power systems with time delay and stochasticity is designed. Based on Lyapunov functional method, some sufficient conditions are proposed to guarantee the rationality and validity of the proposed control law. The closed-loop systems under the control law are asymptotically stable in mean square independent of the time delay. And we through a simulation of a two-machine power system prove the effectiveness of the results proposed in this paper.

Analysis of Power System Low Frequency Oscillation Based on Energy Shift Theory

Science.gov (United States)

Zhang, Junfeng; Zhang, Chunwang; Ma, Daqing

2018-01-01

In this paper, a new method for analyzing low-frequency oscillation between analytic areas based on energy coefficient is proposed. The concept of energy coefficient is proposed by constructing the energy function, and the low-frequency oscillation is analyzed according to the energy coefficient under the current operating conditions; meanwhile, the concept of model energy is proposed to analyze the energy exchange behavior between two generators. Not only does this method provide an explanation of low-frequency oscillation from the energy point of view, but also it helps further reveal the dynamic behavior of complex power systems. The case analysis of four-machine two-area and the power system of Jilin Power Grid proves the correctness and effectiveness of the proposed method in low-frequency oscillation analysis of power system.

Optimization of disk generator performance for base-load power plant systems applications

International Nuclear Information System (INIS)

Teare, J.D.; Loubsky, W.J.; Lytle, J.K.; Louis, J.F.

1980-01-01

Disk generators for use in base-load MHD power plants are examined for both open-cycle and closed-cycle operating modes. The OCD cases are compared with PSPEC results for a linear channel; enthalpy extractions up to 23% with 71% isentropic efficiency are achievable with generator inlet conditions similar to those used in PSPEC, thus confirming that the disk configuration is a viable alternative for base-load power generation. The evaluation of closed-cycle disks includes use of a simplified cycle model. High system efficiencies over a wide range of power levels are obtained for effective Hall coefficients in the range 2.3 to 4.9. Cases with higher turbulence (implying β/sub eff/ less than or equal to 2.4) yield high system efficiencies at power levels of 100 to 500 MW/sub e/. All these CCD cases compare favorably with linear channels reported in the GE ECAS study, yielding higher isentropic efficiences for a given enthalpy extraction. Power densities in the range 70 to 170 MW/m 3 appear feasible, leading to very compact generator configurations

Columnar transmitter based wireless power delivery system for implantable device in freely moving animals.

Science.gov (United States)

Eom, Kyungsik; Jeong, Joonsoo; Lee, Tae Hyung; Lee, Sung Eun; Jun, Sang Bum; Kim, Sung June

2013-01-01

A wireless power delivery system is developed to deliver electrical power to the neuroprosthetic devices that are implanted into animals freely moving inside the cage. The wireless powering cage is designed for long-term animal experiments without cumbersome wires for power supply or the replacement of batteries. In the present study, we propose a novel wireless power transmission system using resonator-based inductive links to increase power efficiency and to minimize the efficiency variations. A columnar transmitter coil is proposed to provide lateral uniformity of power efficiency. Using this columnar transmitter coil, only 7.2% efficiency fluctuation occurs from the maximum transmission efficiency of 25.9%. A flexible polymer-based planar type receiver coil is fabricated and assembled with a neural stimulator and an electrode. Using the designed columnar transmitter coil, the implantable device successfully operates while it moves freely inside the cage.

Thermodynamic assessment of integrated biogas-based micro-power generation system

International Nuclear Information System (INIS)

Hosseini, Seyed Ehsan; Barzegaravval, Hasan; Wahid, Mazlan Abdul; Ganjehkaviri, Abdolsaeid; Sies, Mohsin Mohd

2016-01-01

Highlights: • A thermodynamic modelling of an integrated biogas-based micro-power generation system is reported. • The impact of design parameters on the thermodynamic performance of the system is evaluated. • High turbine inlet temperatures lead the system to the higher energy and exergy efficiency and higher power generation. • Enhancement of GT isentropic efficiency incurs negative effects on the performance of air preheater and heat exchanger. • The rate of power generation increases by the enhancement of steam turbine pressure in ORC. - Abstract: In this paper, a thermodynamic modelling of an integrated biogas (60%CH_4 + 40%CO_2) micro-power generation system for electricity generation is reported. This system involves a gas turbine cycle and organic Rankine cycle (ORC) where the wasted heat of gas turbine cycle is recovered by closed ORC. The net output power of the micro-power generation system is fixed at 1.4 MW includes 1 MW power generated by GT and 0.4 MW by ORC. Energy and exergy assessments and related parametric studies are carried out, and parameters that influence on energy and exergy efficiency are evaluated. The performance of the system with respect to variation of design parameters such as combustion air inlet temperature, turbine inlet temperature, compressor pressure ratio, gas turbine isentropic efficiency and compressor isentropic efficiency (from the top cycle) and steam turbine inlet pressure, and condenser pressure (from bottoming cycle) is evaluated. The results reveal that by the increase of gas turbine isentropic efficiency, the outlet temperature of gas turbine decreases which incurs negative impacts on the performance of air preheater and heat exchanger, however the energy and exergy efficiency increases in the whole system. By the increase of air compressor pressure ratio, the energy and exergy of the combined cycle decreases. The exergy efficiency of ORC alters by the variation of gas turbine parameters which can be

Multi-objective PSO based optimal placement of solar power DG in radial distribution system

Directory of Open Access Journals (Sweden)

Mahesh Kumar

2017-06-01

Full Text Available Ever increasing trend of electricity demand, fossil fuel depletion and environmental issues request the integration of renewable energy into the distribution system. The optimal planning of renewable distributed generation (DG is much essential for ensuring maximum benefits. Hence, this paper proposes the optimal placement of probabilistic based solar power DG into the distribution system. The two objective functions such as power loss reduction and voltage stability index improvement are optimized. The power balance and voltage limits are kept as constraints of the problem. The non-sorting pare to-front based multi-objective particle swarm optimization (MOPSO technique is proposed on standard IEEE 33 radial distribution test system.

System frequency support of permanent magnet synchronous generator-based wind power plant

Science.gov (United States)

Wu, Ziping

With ever-increasing penetration of wind power into modern electric grids all over the world, a trending replacement of conventional synchronous generators by large wind power plants will likely result in the poor overall frequency regulation performance. On the other hand, permanent magnet synchronous generator wind Turbine System (PMSG-WTG) with full power back to back converters tends to become one of the most promising wind turbine technologies thanks to various advantages. It possesses a significant amount of kinetic energy stored in the rotating mass of turbine blades, which can be utilized to enhance the total inertia of power system. Additionally, the deloaded operation and decoupled control of active and reactive power make it possible for PMSG-WTG to provide a fast frequency regulation through full-power converter. First of all, a comprehensive and in-depth survey is conducted to analyze the motivations for incorporating the inertial response and frequency regulation of VSWT into the system frequency regulation. Besides, control classifications, fundamental control concepts and advanced control schemes implemented for auxiliary frequency support of individual WT or wind power plant are elaborated along with a comparison of the potential frequency regulation capabilities of four major types of WTs. Secondly, a Controls Advanced Research Turbine2-Permanent Magnet Synchronous Generator wind turbine (CART2-PMSG) integrated model representing the typical configuration and operation characteristics of PMSG-WT is established in Matlab/Simulink,. Meanwhile, two different rotor-side converter control schemes, including rotor speed-based control and active power-based control, are integrated into this CART2-PMSG integrated model to perform Maximum Power Point Tracking (MPPT) operation over a wide range of wind speeds, respectively. Thirdly, a novel comprehensive frequency regulation (CFR) control scheme is developed and implemented into the CART2-PMSG model based

Computer-based control of nuclear power information systems at international level

International Nuclear Information System (INIS)

Boniface, Ekechukwu; Okonkwo, Obi

2011-01-01

In most highly industrialized countries of the world information plays major role in anti-nuclear campaign. Information and discussions on nuclear power need critical and objective analysis before the structured information presentation to the public to avoid bias anti-nuclear information on one side and neglect of great risk in nuclear power. This research is developing a computer-based information system for the control of nuclear power at international level. The system is to provide easy and fast information highways for the followings: (1) Low Regulatory dose and activity limit as level of high danger for individuals and public. (2) Provision of relevant technical or scientific education among the information carriers in the nuclear power countries. The research is on fact oriented investigation about radioactivity. It also deals with fact oriented education about nuclear accidents and safety. A standard procedure for dissemination of latest findings using technical and scientific experts in nuclear technology is developed. The information highway clearly analyzes the factual information about radiation risk and nuclear energy. Radiation cannot be removed from our environment. The necessity of radiation utilizations defines nuclear energy as two-edge sword. It is therefore, possible to use computer-based information system in projecting and dissemination of expert knowledge about nuclear technology positively and also to use it in directing the public on the safety and control of the nuclear energy. The computer-based information highway for nuclear energy technology is to assist in scientific research and technological development at international level. (author)

Electrical power systems for Mars

Science.gov (United States)

Giudici, Robert J.

1986-01-01

Electrical power system options for Mars Manned Modules and Mars Surface Bases were evaluated for both near-term and advanced performance potential. The power system options investigated for the Mission Modules include photovoltaics, solar thermal, nuclear reactor, and isotope power systems. Options discussed for Mars Bases include the above options with the addition of a brief discussion of open loop energy conversion of Mars resources, including utilization of wind, subsurface thermal gradients, and super oxides. Electrical power requirements for Mission Modules were estimated for three basic approaches: as a function of crew size; as a function of electric propulsion; and as a function of transmission of power from an orbiter to the surface of Mars via laser or radio frequency. Mars Base power requirements were assumed to be determined by production facilities that make resources available for follow-on missions leading to the establishment of a permanently manned Base. Requirements include the production of buffer gas and propellant production plants.

Electrochemical Anti-corrosion System of Iron Tower Based on Solar Power Supply

Directory of Open Access Journals (Sweden)

Tian Tian

2018-01-01

Full Text Available Aiming at the serious problem of the corrosion of the transmission tower in the coastal area or in the harsh industrial area, a kind of electro-chemical anti-corrosion system based on solar power is designed. The system consists of a solar power module and an electrochemical anti-corrosion module: The solar power module consists of a solar panel, a photovoltaic controller, a accumulator and a constant potentiometer. The Electrochemical anti-corrosion modules include an anode block and an anode bed and reference electrode. The photovoltaic energy technology and forced current cathodic protection technology are used in the system, to achieve the effective protection of the tower anti-corrosion. Solar power supply to the nearest, solve the long-distance transmission loss and the high installation costs, form a simple structure, stable operation, low cost, clean and environmental protection, long service life of anti-corrosion system, with good economic efficiency and social benefits. It is of great significance to ensure the safe operation of the tower, maintain the normal operation of the power grid, and even promotes the optimization and upgrading of the industrial structure, save energy and reduces emissions, improve the safe and stable operation of the power system and the economic benefits, etc.

Development of module-based simulation system for nuclear power plant

International Nuclear Information System (INIS)

Yoshikawa, H.

1990-01-01

Module-based Simulation System (MSS) has been developed to realize a new software environment enabling versatile dynamic simulation of a complex nuclear power plant system flexibly. Described in the paper are (i) fundamental methods utilized in MMS and its software systemization, (ii) development of human interface system to help users in generating integrated simulation programs automatically, and (iii) development of an intelligent user support system for helping users in the two phases of automatical semantic diagnosis and consultation to automatic input data setup for the MSS-generated programs

Data warehouse based decision support system in nuclear power plants

International Nuclear Information System (INIS)

Nadinic, B.

2004-01-01

Safety is an important element in business decision making processes in nuclear power plants. Information about component reliability, structures and systems, data recorded during the nuclear power plant's operation and outage periods, as well as experiences from other power plants are located in different database systems throughout the power plant. It would be possible to create a decision support system which would collect data, transform it into a standardized form and store it in a single location in a format more suitable for analyses and knowledge discovery. This single location where the data would be stored would be a data warehouse. Such data warehouse based decision support system could help make decision making processes more efficient by providing more information about business processes and predicting possible consequences of different decisions. Two main functionalities in this decision support system would be an OLAP (On Line Analytical Processing) and a data mining system. An OLAP system would enable the users to perform fast, simple and efficient multidimensional analysis of existing data and identify trends. Data mining techniques and algorithms would help discover new, previously unknown information from the data as well as hidden dependencies between various parameters. Data mining would also enable analysts to create relevant prediction models that could predict behaviour of different systems during operation and inspection results during outages. The basic characteristics and theoretical foundations of such decision support system are described and the reasons for choosing a data warehouse as the underlying structure are explained. The article analyzes obvious business benefits of such system as well as potential uses of OLAP and data mining technologies. Possible implementation methodologies and problems that may arise, especially in the field of data integration, are discussed and analyzed.(author)

RF-based power distribution system for optogenetic experiments

Science.gov (United States)

Filipek, Tomasz A.; Kasprowicz, Grzegorz H.

2017-08-01

In this paper, the wireless power distribution system for optogenetic experiment was demonstrated. The design and the analysis of the power transfer system development is described in details. The architecture is outlined in the context of performance requirements that had to be met. We show how to design a wireless power transfer system using resonant coupling circuits which consist of a number of receivers and one transmitter covering the entire cage area with a specific power density. The transmitter design with the full automated protection stage is described with detailed consideration of the specification and the construction of the transmitting loop antenna. In addition, the design of the receiver is described, including simplification of implementation and the minimization of the impact of component tolerances on the performance of the distribution system. The conducted analysis has been confirmed by calculations and measurement results. The presented distribution system was designed to provide 100 mW power supply to each of the ten possible receivers in a limited 490 x 350 mm cage space while using a single transmitter working at the coupling resonant frequency of 27 MHz.

DC-based smart PV-powered home energy management system based on voltage matching and RF module

Science.gov (United States)

Hasan, W. Z. W.

2017-01-01

The main tool for measuring system efficiency in homes and offices is the energy monitoring of the household appliances’ consumption. With the help of GUI through a PC or smart phone, there are various applications that can be developed for energy saving. This work describes the design and prototype implementation of a wireless PV-powered home energy management system under a DC-distribution environment, which allows remote monitoring of appliances’ energy consumptions and power rate quality. The system can be managed by a central computer, which obtains the energy data based on XBee RF modules that access the sensor measurements of system components. The proposed integrated prototype framework is characterized by low power consumption due to the lack of components and consists of three layers: XBee-based circuit for processing and communication architecture, solar charge controller, and solar-battery-load matching layers. Six precise analogue channels for data monitoring are considered to cover the energy measurements. Voltage, current and temperature analogue signals were accessed directly from the remote XBee node to be sent in real time with a sampling frequency of 11–123 Hz to capture the possible surge power. The performance shows that the developed prototype proves the DC voltage matching concept and is able to provide accurate and precise results. PMID:28934271

DC-based smart PV-powered home energy management system based on voltage matching and RF module.

Directory of Open Access Journals (Sweden)

Ahmad H Sabry

Full Text Available The main tool for measuring system efficiency in homes and offices is the energy monitoring of the household appliances' consumption. With the help of GUI through a PC or smart phone, there are various applications that can be developed for energy saving. This work describes the design and prototype implementation of a wireless PV-powered home energy management system under a DC-distribution environment, which allows remote monitoring of appliances' energy consumptions and power rate quality. The system can be managed by a central computer, which obtains the energy data based on XBee RF modules that access the sensor measurements of system components. The proposed integrated prototype framework is characterized by low power consumption due to the lack of components and consists of three layers: XBee-based circuit for processing and communication architecture, solar charge controller, and solar-battery-load matching layers. Six precise analogue channels for data monitoring are considered to cover the energy measurements. Voltage, current and temperature analogue signals were accessed directly from the remote XBee node to be sent in real time with a sampling frequency of 11-123 Hz to capture the possible surge power. The performance shows that the developed prototype proves the DC voltage matching concept and is able to provide accurate and precise results.

DC-based smart PV-powered home energy management system based on voltage matching and RF module.

Science.gov (United States)

Sabry, Ahmad H; Hasan, W Z W; Ab Kadir, Mza; Radzi, M A M; Shafie, S

2017-01-01

The main tool for measuring system efficiency in homes and offices is the energy monitoring of the household appliances' consumption. With the help of GUI through a PC or smart phone, there are various applications that can be developed for energy saving. This work describes the design and prototype implementation of a wireless PV-powered home energy management system under a DC-distribution environment, which allows remote monitoring of appliances' energy consumptions and power rate quality. The system can be managed by a central computer, which obtains the energy data based on XBee RF modules that access the sensor measurements of system components. The proposed integrated prototype framework is characterized by low power consumption due to the lack of components and consists of three layers: XBee-based circuit for processing and communication architecture, solar charge controller, and solar-battery-load matching layers. Six precise analogue channels for data monitoring are considered to cover the energy measurements. Voltage, current and temperature analogue signals were accessed directly from the remote XBee node to be sent in real time with a sampling frequency of 11-123 Hz to capture the possible surge power. The performance shows that the developed prototype proves the DC voltage matching concept and is able to provide accurate and precise results.

Modular VSC converter based HVDC power transmission from offshore wind power plant: Compared to the conventional HVAC system

DEFF Research Database (Denmark)

Sharma, Ranjan; Rasmussen, Tonny Wederberg; Jensen, Kim Høj

2010-01-01

power transmission options with HVDC systems are under consideration. In this paper, a comparison between a conventional HVAC transmission system and a HVDC system equipped with modular voltage source converters is provided. The comparison is based on the total energy transmission capability...

Revised sequence components power system models for unbalanced power system studies

Energy Technology Data Exchange (ETDEWEB)

Abdel-Akher, M. [Tunku Abdul Rahman Univ., Kuala Lumpur (Malaysia); Nor, K.-M. [Univ. of Technology Malaysia, Johor (Malaysia); Rashid, A.H.A. [Univ. of Malaya, Kuala Lumpur (Malaysia)

2007-07-01

The principle method of analysis using positive, negative, and zero-sequence networks has been used to examine the balanced power system under both balanced and unbalanced loading conditions. The significant advantage of the sequence networks is that the sequence networks become entirely uncoupled in the case of balanced three-phase power systems. The uncoupled sequence networks then can be solved in independent way such as in fault calculation programs. However, the hypothesis of balanced power systems cannot be considered in many cases due to untransposed transmission lines; multiphase line segments in a distribution power system; or transformer phase shifts which cannot be incorporated in the existing models. A revised sequence decoupled power system models for analyzing unbalanced power systems based on symmetrical networks was presented in this paper. These models included synchronous machines, transformers, transmission lines, and voltage regulators. The models were derived from their counterpart's models in phase coordinates frame of reference. In these models, the three sequence networks were fully decoupled with a three-phase coordinates features such as transformer phase shifts and transmission line coupling. The proposed models were used to develop an unbalanced power-flow program for analyzing both balanced and unbalanced networks. The power flow solution was identical to results obtained from a full phase coordinate three-phase power-flow program. 11 refs., 3 tabs.

Overview of DFIG-based Wind Power System Resonances under Weak Networks

DEFF Research Database (Denmark)

Song, Yipeng; Blaabjerg, Frede

2017-01-01

The wind power generation techniques are continuing to develop and increasing numbers of Doubly Fed Induction Generator (DFIG)-based wind power systems are connecting to the on-shore and off-shore grids, local standalone weak networks, and also micro grid applications. The impedances of the weak...... scale of DFIG system with different parameters; 3) L or LCL filter adopted in the Grid Side Converter (GSC); 4) rotor speed; 5) current closed-loop controller parameters and 6) digital control delay will be discussed in this paper. On the basis of the analysis, active damping strategies for HFR using...

Power System Event Ranking Using a New Linear Parameter-Varying Modeling with a Wide Area Measurement System-Based Approach

Directory of Open Access Journals (Sweden)

Mohammad Bagher Abolhasani Jabali

2017-07-01

Full Text Available Detecting critical power system events for Dynamic Security Assessment (DSA is required for reliability improvement. The approach proposed in this paper investigates the effects of events on dynamic behavior during nonlinear system response while common approaches use steady-state conditions after events. This paper presents some new and enhanced indices for event ranking based on time-domain simulation and polytopic linear parameter-varying (LPV modeling of a power system. In the proposed approach, a polytopic LPV representation is generated via linearization about some points of the nonlinear dynamic behavior of power system using wide-area measurement system (WAMS concepts and then event ranking is done based on the frequency response of the system models on the vertices. Therefore, the nonlinear behaviors of the system in the time of fault occurrence are considered for events ranking. The proposed algorithm is applied to a power system using nonlinear simulation. The comparison of the results especially in different fault conditions shows the advantages of the proposed approach and indices.

Computer-aided power systems analysis

CERN Document Server

Kusic, George

2008-01-01

Computer applications yield more insight into system behavior than is possible by using hand calculations on system elements. Computer-Aided Power Systems Analysis: Second Edition is a state-of-the-art presentation of basic principles and software for power systems in steady-state operation. Originally published in 1985, this revised edition explores power systems from the point of view of the central control facility. It covers the elements of transmission networks, bus reference frame, network fault and contingency calculations, power flow on transmission networks, generator base power setti

Configuring a fuel cell based residential combined heat and power system

Science.gov (United States)

Ahmed, Shabbir; Papadias, Dionissios D.; Ahluwalia, Rajesh K.

2013-11-01

The design and performance of a fuel cell based residential combined heat and power (CHP) system operating on natural gas has been analyzed. The natural gas is first converted to a hydrogen-rich reformate in a steam reformer based fuel processor, and the hydrogen is then electrochemically oxidized in a low temperature polymer electrolyte fuel cell to generate electric power. The heat generated in the fuel cell and the available heat in the exhaust gas is recovered to meet residential needs for hot water and space heating. Two fuel processor configurations have been studied. One of the configurations was explored to quantify the effects of design and operating parameters, which include pressure, temperature, and steam-to-carbon ratio in the fuel processor, and fuel utilization in the fuel cell. The second configuration applied the lessons from the study of the first configuration to increase the CHP efficiency. Results from the two configurations allow a quantitative comparison of the design alternatives. The analyses showed that these systems can operate at electrical efficiencies of ∼46% and combined heat and power efficiencies of ∼90%.

FPGA based control system for -100 kV, 25 A Crowbarless DC power supply

International Nuclear Information System (INIS)

Upadhyay, R.; Tripathi, A.; Badapanda, M.K.; Lad, M.

2015-01-01

FPGA based digital control system has been developed for -100 kV, 25 A solid state modular crowbarless DC klystron bias power supply of 1 MW, 352.2 MHz RF test stand. The control system has capability to operate this power supply either in CW or pulse mode. Central controller, PSM controller and graphical user interface are key parts of this control system. Central controller monitors the status of various subsystems of this power supply like 11 kV step start unit, four numbers of main transformers each having 44 numbers of secondary windings and 176 numbers of switch power modules for deciding the number of power modules to be put ON and their duty cycles depending on the set output voltage and current. PSM controller sends appropriate control signal to the switch power modules through fibre optic lines and communicates it to the central controller. Linux based graphical user interface has been developed which enables the user to set the operating parameters along with their trip limits and displays the information of critical parameters of this power supply on a local touch screen panel. Provision for remote control and supervision is also provided through a separate PC connected to the main control system via Ethernet. The control system has capability to trip the power supply within 5 μsec in case any parameter exceeds its set limit. Suitable data logging feature is incorporated for offline fault analysis. The control system architecture along with its software protection interlocks are presented in this paper. The performance of the control system has been verified during operation of -100 kV, 25 A DC power supply with 1 MW, 352.2 MHz klystron amplifier. (author)

76 FR 2368 - Balance Power Systems, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes...

Science.gov (United States)

2011-01-13

... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. ER11-2331-000] Balance Power Systems, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes Request for Blanket... proceeding of Balance Power Systems, LLC's application for market-based rate authority, with an accompanying...

Basic Concept and Theoretical Study of Condition-based Maintenance for Power Transmission System

Institute of Scientific and Technical Information of China (English)

LIMing; HAN Xueshan; YANG Ming; GUO Zhihong

2011-01-01

The appropriate maintenance time for the single equipment can be found easily and efficiently under the background of condition-based maintenance. However, from the perspective of the whole power system, discrepancy between equipment individual and the whole power system would appear. Once this discrepancy can not be coordinated, it will certainly cause contradiction and conflict between individual equipment and the whole system, and lose the integral efficiency. To solve this contradiction and conflicts is of significant meaning.

Optimal design of base isolation and energy dissipation system for nuclear power plant structures

International Nuclear Information System (INIS)

Zhou Fulin

1991-01-01

This paper suggests the method of optimal design of base isolation and energy dissipation system for earthquake resistant nuclear power plant structures. This method is based on dynamic analysis, shaking table tests for a 1/4 scale model, and a great number of low cycle fatigue failure tests for energy dissipating elements. A set of calculation formulas for optimal design of structures with base isolation and energy dissipation system were introduced, which are able to be used in engineering design for earthquake resistant nuclear power plant structures or other kinds of structures. (author)

Hybrid Power Management-Based Vehicle Architecture

Science.gov (United States)

Eichenberg, Dennis J.

2011-01-01

Hybrid Power Management (HPM) is the integration of diverse, state-of-the-art power devices in an optimal configuration for space and terrestrial applications (s ee figure). The appropriate application and control of the various power devices significantly improves overall system performance and efficiency. The basic vehicle architecture consists of a primary power source, and possibly other power sources, that provides all power to a common energy storage system that is used to power the drive motors and vehicle accessory systems. This architecture also provides power as an emergency power system. Each component is independent, permitting it to be optimized for its intended purpose. The key element of HPM is the energy storage system. All generated power is sent to the energy storage system, and all loads derive their power from that system. This can significantly reduce the power requirement of the primary power source, while increasing the vehicle reliability. Ultracapacitors are ideal for an HPM-based energy storage system due to their exceptionally long cycle life, high reliability, high efficiency, high power density, and excellent low-temperature performance. Multiple power sources and multiple loads are easily incorporated into an HPM-based vehicle. A gas turbine is a good primary power source because of its high efficiency, high power density, long life, high reliability, and ability to operate on a wide range of fuels. An HPM controller maintains optimal control over each vehicle component. This flexible operating system can be applied to all vehicles to considerably improve vehicle efficiency, reliability, safety, security, and performance. The HPM-based vehicle architecture has many advantages over conventional vehicle architectures. Ultracapacitors have a much longer cycle life than batteries, which greatly improves system reliability, reduces life-of-system costs, and reduces environmental impact as ultracapacitors will probably never need to be

Omnidirectional Wireless Power Transfer System Based on Rotary Transmitting Coil for Household Appliances

Directory of Open Access Journals (Sweden)

Gongjun Liu

2018-04-01

Full Text Available An omnidirectional magnetically coupled resonant wireless power transfer (WPT system based on rotary transmitting coil is presented. The proposed scheme can ease the variations of the transfer efficiency and output power caused by the deviation of transfer direction, and improve the unbalanced power distribution phenomenon between the receivers, which are still not fully achieved in current WPT systems. The modified coupled-mode model is built first to describe the non-rotary multi-receiver WPT system. The analysis indicates that the transfer efficiency and output power of the system can be expressed as functions of the deviation angle between the transmitting coil and receiving coil, which has a non-negligible influence on the system performances. Then, the modified high order coupled-mode model containing time-varying parameters about the deviation angle is derived for the proposed omnidirectional WPT system. Theoretical analysis and simulated results indicate that this system can transfer power to multiple receivers around the transmitter synchronously and evenly, which is very suitable for wireless charging for household appliances indoors. The scheme feasibility and theoretical analysis are verified by experimental results.

Promise of a low power mobile CPU based embedded system in artificial leg control.

Science.gov (United States)

Hernandez, Robert; Zhang, Fan; Zhang, Xiaorong; Huang, He; Yang, Qing

2012-01-01

This paper presents the design and implementation of a low power embedded system using mobile processor technology (Intel Atom™ Z530 Processor) specifically tailored for a neural-machine interface (NMI) for artificial limbs. This embedded system effectively performs our previously developed NMI algorithm based on neuromuscular-mechanical fusion and phase-dependent pattern classification. The analysis shows that NMI embedded system can meet real-time constraints with high accuracies for recognizing the user's locomotion mode. Our implementation utilizes the mobile processor efficiently to allow a power consumption of 2.2 watts and low CPU utilization (less than 4.3%) while executing the complex NMI algorithm. Our experiments have shown that the highly optimized C program implementation on the embedded system has superb advantages over existing PC implementations on MATLAB. The study results suggest that mobile-CPU-based embedded system is promising for implementing advanced control for powered lower limb prostheses.

Control of power plants and power systems. Proceedings

International Nuclear Information System (INIS)

Canales-Ruiz, R.

1996-01-01

The 88 papers in this volume constitute the proceedings of the International Federation of Automatic Control Symposium held in Mexico in 1995. The broad areas which they cover are: self tuning control; power plant operations; dynamic stability; fuzzy logic applications; power plants modelling; artificial intelligence applications; power plants simulation; voltage control; control of hydro electric units; state estimation; fault diagnosis and monitoring systems; system expansion and operation planning; security assessment; economic dispatch and optimal load flow; adaptive control; distribution; transient stability and preventive control; modelling and control of nuclear plant; knowledge data bases for automatic learning methods applied to power system dynamic security assessment; control of combined cycle units; power control centres. Separate abstracts have been prepared for the three papers relating to nuclear power plants. (UK)

Multiagent based protection and control in decentralized electric power systems

DEFF Research Database (Denmark)

Saleem, Arshad; Lind, Morten; Veloso, Manuela

2010-01-01

Electric power systems are going through a major change both in their physical and control structure. A large num- ber of small and geographically dispersed power generation units (e.g., wind turbines, solar cells, plug-in electric cars) are replacing big centralized power plants. This shift has...... created interesting possibilities for application of intelligent systems such as multiagent systems for control and automation in electric power systems. This paper describes work on designing a multiagent system for protection and control of electric power distribution networks.It demonstrates how...... explicit modeling of capabilities, states, roles and role transition in agents can capture the control and automation in electric power systems. We present illustrative results from using our proposed schema in realistic simulations....

Power control and management of the grid containing largescale wind power systems

Science.gov (United States)

Aula, Fadhil Toufick

The ever increasing demand for electricity has driven many countries toward the installation of new generation facilities. However, concerns such as environmental pollution and global warming issues, clean energy sources, high costs associated with installation of new conventional power plants, and fossil fuels depletion have created many interests in finding alternatives to conventional fossil fuels for generating electricity. Wind energy is one of the most rapidly growing renewable power sources and wind power generations have been increasingly demanded as an alternative to the conventional fossil fuels. However, wind power fluctuates due to variation of wind speed. Therefore, large-scale integration of wind energy conversion systems is a threat to the stability and reliability of utility grids containing these systems. They disturb the balance between power generation and consumption, affect the quality of the electricity, and complicate load sharing and load distribution managing and planning. Overall, wind power systems do not help in providing any services such as operating and regulating reserves to the power grid. In order to resolve these issues, research has been conducted in utilizing weather forecasting data to improve the performance of the wind power system, reduce the influence of the fluctuations, and plan power management of the grid containing large-scale wind power systems which consist of doubly-fed induction generator based energy conversion system. The aims of this research, my dissertation, are to provide new methods for: smoothing the output power of the wind power systems and reducing the influence of their fluctuations, power managing and planning of a grid containing these systems and other conventional power plants, and providing a new structure of implementing of latest microprocessor technology for controlling and managing the operation of the wind power system. In this research, in order to reduce and smooth the fluctuations, two

Voltage sensitivity based reactive power control on VSC-HVDC in a wind farm connected hybrid multi-infeed HVDC system

DEFF Research Database (Denmark)

Liu, Yan; Chen, Zhe

2013-01-01

With increasing application of both Line Commutated Converter based High Voltage Direct Current (LCC-HVDC) systems and Voltage Source Converter based HVDC (VSC-HVDC) links, a new type of system structure named Hybrid Multi-Infeed HVDC (HMIDC) system is formed in the modern power systems. This paper...... presents the operation and control method of the wind farm connected HMIDC system. The wind power fluctuation takes large influence to the system voltages. In order to reduce the voltage fluctuation of LCC-HVDC infeed bus caused by the wind power variation, a voltage sensitivity-based reactive power...

The reactor power control system based on digital control in nuclear power plant

International Nuclear Information System (INIS)

Liu Chong; Zhou Jianliang; Tan Ping

2010-01-01

The PLC (Programmable Logical Controller), digital communication and redundant techniques are applied in the rod control and position indication system(namely the reactor power control system) to perform the power control in the 300 MW reactor automatically and integrally in Qinshan Phase I project. This paper introduces the features, digital design methods of hardware of the instrumentation and control system (I and C) in the reactor power control. It is more convenient for the information exchange by human-machine interface (HMI), operation and maintenance, and the system reliability has been greatly improved after the project being reconstructed. (authors)

State-of-the-art research: optimal investment in market-based electric power systems

Energy Technology Data Exchange (ETDEWEB)

Hope, Einar; Skjeret, Frode

2008-04-15

The purpose of this state-of-the-art research paper is to surveying the literature on investment in market based electric power systems as a background for identifying and discussing some important issues in the optimal design and operation of such systems. A fundamental distinction has to be made between investment in the competitive part of the power system (generation and trading) on the one hand and the natural monopoly part (network infrastructure) on the other. The paper starts with a listing and discussion on market characteristics and properties of electric power and goes on to discussing performance criteria and potential sources of market failure for optimal electric power investment. After the literature survey there is a discussion of conditions under which optimal investment may occur. (author). 78 refs., figs

The knowledge-based off-site emergency response system for a nuclear power plant

International Nuclear Information System (INIS)

Ho, L.W.; Loa, W.W.; Wang, C.L.

1987-01-01

A knowledge-based expert system for a nuclear power plant off-site emergency response system is described. The system incorporates the knowledge about the nuclear power plant behaviours, site environment and site geographic factors, etc. The system is developed using Chinshan nuclear power station of Taipower Company, Taiwan, ROC as a representative model. The objectives of developing this system are to provide an automated intelligent system with functions of accident simulation, prediction and with learning capabilities to supplement the actions of the emergency planners and accident managers in order to protect the plant personnel and the surrounding population, and prevent or mitigate property damages resulting from the plant accident. The system is capable of providing local and national authorities with rapid retrieval data from the site characteristics and accident progression. The system can also provide the framework for allocation of available resources and can handle the uncertainties in data and models

Oxygen transport membrane reactor based method and system for generating electric power

Science.gov (United States)

Kelly, Sean M.; Chakravarti, Shrikar; Li, Juan

2017-02-07

A carbon capture enabled system and method for generating electric power and/or fuel from methane containing sources using oxygen transport membranes by first converting the methane containing feed gas into a high pressure synthesis gas. Then, in one configuration the synthesis gas is combusted in oxy-combustion mode in oxygen transport membranes based boiler reactor operating at a pressure at least twice that of ambient pressure and the heat generated heats steam in thermally coupled steam generation tubes within the boiler reactor; the steam is expanded in steam turbine to generate power; and the carbon dioxide rich effluent leaving the boiler reactor is processed to isolate carbon. In another configuration the synthesis gas is further treated in a gas conditioning system configured for carbon capture in a pre-combustion mode using water gas shift reactors and acid gas removal units to produce hydrogen or hydrogen-rich fuel gas that fuels an integrated gas turbine and steam turbine system to generate power. The disclosed method and system can also be adapted to integrate with coal gasification systems to produce power from both coal and methane containing sources with greater than 90% carbon isolation.

Dynamic Security Assessment of Danish Power System Based on Decision Trees: Today and Tomorrow

DEFF Research Database (Denmark)

Rather, Zakir Hussain; Liu, Leo; Chen, Zhe

2013-01-01

The research work presented in this paper analyzes the impact of wind energy, phasing out of central power plants and cross border power exchange on dynamic security of Danish Power System. Contingency based decision tree (DT) approach is used to assess the dynamic security of present and future...

PERSPECTIVE TRANSPORT-POWER SYSTEM BASED ON THE INTEGRATION OF MAGLEV-TECHNOLOGY AND DISTRIBUTED PHOTO-ELECTRIC STATION

Directory of Open Access Journals (Sweden)

V. O. Dzenzerskiy

2018-02-01

Full Text Available Purpose. The research main purpose is the perfection of magnetolevitating technology on electrodynamic suspension and providing its functioning on the base of ecologically rational energy systems. It means creation of the MAGLEV transport-power system which uses renewable energy sources (in particular, photoelectric converters and is connected to national/local networks as an energy user and producer simultaneously. Methodology. Conducted research, analysis and summary conclusions are based both on the results of works on the given subject, and own works of authors. The methods of systems analysis and computer design of components of the large cyber-physical transport-power system were used during research conducting. Findings. The physical-technical foundations of conception of the perspective transport-power system, which includes high-speed ground vehicle on electrodynamic suspension and distributed photo-electric energy complex are developed. The adapt to the performance of the given transport type and guaranteeing its safe functioning in any weather terms. Originality. For the first time authors substantiated the possibility for creation of single transport complex uniting the speed magnetolevitating system and distributed power supply system on the base of sun energy. It is simultaneously the inalienable part of the precision fast-acting control system, working in the real-time mode. Practical value. The offered scientific-technical solution allows on the base of renewable energy source to solve the problems of power supply and a high-speed transport control. Due to the inclusion of the distributed power supply system into local intellectual networks on the SMART-grid technology it gives the possibility to optimize energy consumption of territories neighboring to high-speed way.

Recent advances and challenges of fuel cell based power system architectures and control – A review

DEFF Research Database (Denmark)

Das, Vipin; Sanjeevikumar, Padmanaban; Venkitusamy, Karthikeyan

2017-01-01

by bit with expansion in current because of losses associated with fuel cell. It is difficult in handling large rated fuel cell based power system without regulating mechanism. The issue connected with fuel based structural planning and the arrangements are widely investigated for all sorts......Renewable energy generation is rapidly growing in the power sector industry and widely used for two categories: grid connected and standalone system. This paper gives the insights about fuel cell operation and application of various power electronics systems. The fuel cell voltage decreases bit...

Design and optimization of a 3-coil resonance-based wireless power transfer system for biomedical implants

KAUST Repository

Yi, Ying

2014-09-01

This paper presents a resonance-based wireless power transfer system using a single layer of inductor coil windings, in a pancake configuration, in order to obtain a compact system for implantable electronic applications. We theoretically analyzed the system and characterized it by measuring its inductance, self-resonant frequency, and quality factor Q. In our resonance-based wireless power transfer prototype, we proposed a 3-coil system, using two 15-mm radius implantable coils, with a resonance frequency of 6.76MHz. This system can effectively transfer power for a distance of up to 50mm. Moreover, our proposed 3-coil system can achieve a high Q-factor and has a comparable power transfer efficiency (PTE) to previously reported works about 3-coil and 4-coil systems. The experimental PTE can achieve 82.4% at a separation distance of 20mm and more than 10% PTE at a distance of 40mm.

Design and optimization of a 3-coil resonance-based wireless power transfer system for biomedical implants

KAUST Repository

Yi, Ying; Buttner, Ulrich; Fan, Yiqiang; Foulds, Ian G.

2014-01-01

This paper presents a resonance-based wireless power transfer system using a single layer of inductor coil windings, in a pancake configuration, in order to obtain a compact system for implantable electronic applications. We theoretically analyzed the system and characterized it by measuring its inductance, self-resonant frequency, and quality factor Q. In our resonance-based wireless power transfer prototype, we proposed a 3-coil system, using two 15-mm radius implantable coils, with a resonance frequency of 6.76MHz. This system can effectively transfer power for a distance of up to 50mm. Moreover, our proposed 3-coil system can achieve a high Q-factor and has a comparable power transfer efficiency (PTE) to previously reported works about 3-coil and 4-coil systems. The experimental PTE can achieve 82.4% at a separation distance of 20mm and more than 10% PTE at a distance of 40mm.

Differential evolution algorithm based automatic generation control for interconnected power systems with

Directory of Open Access Journals (Sweden)

Banaja Mohanty

2014-09-01

Full Text Available This paper presents the design and performance analysis of Differential Evolution (DE algorithm based Proportional–Integral (PI and Proportional–Integral–Derivative (PID controllers for Automatic Generation Control (AGC of an interconnected power system. Initially, a two area thermal system with governor dead-band nonlinearity is considered for the design and analysis purpose. In the proposed approach, the design problem is formulated as an optimization problem control and DE is employed to search for optimal controller parameters. Three different objective functions are used for the design purpose. The superiority of the proposed approach has been shown by comparing the results with a recently published Craziness based Particle Swarm Optimization (CPSO technique for the same interconnected power system. It is noticed that, the dynamic performance of DE optimized PI controller is better than CPSO optimized PI controllers. Additionally, controller parameters are tuned at different loading conditions so that an adaptive gain scheduling control strategy can be employed. The study is further extended to a more realistic network of two-area six unit system with different power generating units such as thermal, hydro, wind and diesel generating units considering boiler dynamics for thermal plants, Generation Rate Constraint (GRC and Governor Dead Band (GDB non-linearity.

Design and realization of temperature measurement system based on optical fiber temperature sensor for wireless power transfer

Science.gov (United States)

Chen, Xi; Zeng, Shuang; Liu, Xiulan; Jin, Yuan; Li, Xianglong; Wang, Xiaochen

2018-02-01

The electric vehicles (EV) have become accepted by increasing numbers of people for the environmental-friendly advantages. A novel way to charge the electric vehicles is through wireless power transfer (WPT). The wireless power transfer is a high power transfer system. The high currents flowing through the transmitter and receiver coils increasing temperature affects the safety of person and charging equipment. As a result, temperature measurement for wireless power transfer is needed. In this paper, a temperature measurement system based on optical fiber temperature sensors for electric vehicle wireless power transfer is proposed. Initially, the thermal characteristics of the wireless power transfer system are studied and the advantages of optical fiber sensors are analyzed. Then the temperature measurement system based on optical fiber temperature sensor is designed. The system consists of optical subsystem, data acquisition subsystem and data processing subsystem. Finally, the system is tested and the experiment result shows that the system can realize 1°C precision and can acquire real-time temperature distribution of the coils, which can meet the requirement of the temperature measuring for wireless power transfer.

A power conditioning system for thermoelectric generator based on interleaved Boost converter with MPPT control

DEFF Research Database (Denmark)

Ni, L.-X; Sun, K.; Zhang, L.

2011-01-01

The thermoelectric generation (TEG) system has its special charactristics of high stablility, low voltage and high current output, which is different from PV modules. The power conditioning system and control schemes used in PV applications cannot be directly applied to TEG applications. A power...... conditioning system for TEG based on interleaved Boost converter with maximum power point tracking (MPPT) control is investigated in this paper. Since an internal resistance exists inside TEG modules, an improved perturbation and observation (P&O) MPPT control scheme with power limit is proposed to extract...... maximum power from TEG by matching the load with internal resistance. Since the battery is usually employed as the load for TEG systems, the interleaved Boost converter operates in two different modes for battery charging: before the battery is fully charged, the system outputs the maximum power (MPPT...

Control Strategy Based on Wavelet Transform and Neural Network for Hybrid Power System

Directory of Open Access Journals (Sweden)

Y. D. Song

2013-01-01

Full Text Available This paper deals with an energy management of a hybrid power generation system. The proposed control strategy for the energy management is based on the combination of wavelet transform and neural network arithmetic. The hybrid system in this paper consists of an emulated wind turbine generator, PV panels, DC and AC loads, lithium ion battery, and super capacitor, which are all connected on a DC bus with unified DC voltage. The control strategy is responsible for compensating the difference between the generated power from the wind and solar generators and the demanded power by the loads. Wavelet transform decomposes the power difference into smoothed component and fast fluctuated component. In consideration of battery protection, the neural network is introduced to calculate the reference power of battery. Super capacitor (SC is controlled to regulate the DC bus voltage. The model of the hybrid system is developed in detail under Matlab/Simulink software environment.

Coordinated Control Strategies of VSC-HVDC-Based Wind Power Systems for Low Voltage Ride Through

Directory of Open Access Journals (Sweden)

Xinyin Zhang

2015-07-01

Full Text Available The Voltage Source Converter-HVDC (VSC-HVDC system applied to wind power generation can solve large scale wind farm grid-connection and long distance transmission problems. However, the low voltage ride through (LVRT of the VSC-HVDC connected wind farm is a key technology issue that must be solved, and it is currently lacking an economic and effective solution. In this paper, a LVRT coordinated control strategy is proposed for the VSC-HVDC-based wind power system. In this strategy, the operation and control of VSC-HVDC and wind farm during the grid fault period is improved. The VSC-HVDC system not only provides reactive power support to the grid, but also effectively maintains the power balance and DC voltage stability by reducing wind-farm power output, without increasing the equipment investment. Correspondingly, to eliminate the influence on permanent magnet synchronous generator (PMSG-based wind turbine (WT systems, a hierarchical control strategy is designed. The speed and validity of the proposed LVRT coordinated control strategy and hierarchical control strategy were verified by MATLAB/Simulink simulations.

Low-power FLC-based retromodulator communications system

Science.gov (United States)

Swenson, Charles M.; Steed, Clark A.; de La Rue, Imelda A.; Fugate, Robert Q.

1997-05-01

On September 15, 1996, researchers from Utah State University/Space Dynamics Lab in conjunction with Phillips Lab/Starfire Optical Range and Kjome Research successfully flew and tested a retromodulator laser communication package on a high altitude balloon. This paper addresses the layout and hardware used for the communication link, as well as presenting some preliminary data collected during the 6 hour flight of the balloon. The package was a proof of concept demonstration system for a low-power laser communications systems for small, low Earth orbiting satellites. The ferroelectric liquid crystal based retromodulator design of Utah State provided test patterns for modulation rates up to 20 kilo bits per second. Data was successfully downlinked using a 1200 bps RS232 format and a simplistic receiver. The Starfire Optical Range 1.5-meter telescope located on Kirtland AFB, tracked the balloon, which reached a float altitude of 31 km and collected the modulated light reflected from the payload.

Integrated Multimedia Based Intelligent Group Decision Support System for Electrical Power Network

OpenAIRE

Ajay Kumar Saxena; S. 0. Bhatnagar; P. K Saxena

2002-01-01

Electrical Power Network in recent time requires an intelligent, virtual environment based decision process for the coordination of all its individual elements and the interrelated tasks. Its ultimate goal is to achieve maximum productivity and efficiency through the efficient and effective application of generation, transmission, distribution, pricing and regulatory systems. However, the complexity of electrical power network and the presence of conflicting multiple goals and objectives p...

Review of Power System Stability with High Wind Power Penetration

DEFF Research Database (Denmark)

Hu, Rui; Hu, Weihao; Chen, Zhe

2015-01-01

analyzing methods and stability improvement approaches. With increasing wind power penetration, system balancing and the reduced inertia may cause a big threaten for stable operation of power systems. To mitigate or eliminate the wind impacts for high wind penetration systems, although the practical......This paper presents an overview of researches on power system stability with high wind power penetration including analyzing methods and improvement approaches. Power system stability issues can be classified diversely according to different considerations. Each classified issue has special...... and reliable choices currently are the strong outside connections or sufficient reserve capacity constructions, many novel theories and approaches are invented to investigate the stability issues, looking forward to an extra-high penetration or totally renewable resource based power systems. These analyzing...

Open system architecture for condition based maintenance applied to a hydroelectric power plant

Energy Technology Data Exchange (ETDEWEB)

Amaya, E.J.; Alvares, A.J. [University of Brasilia (UnB), DF (Brazil). Mechanical and Mechatronic Dept.], Emails: eamaya@unb.br, alvares@AlvaresTech.com; Gudwin, R.R. [State University of Campinas (UNICAMP), SP (Brazil). Computer Engineering and Industrial Automation Dept.], E-mail: gudwin@dca.fee.unicamp.br

2009-07-01

The hydroelectric power plant of Balbina is implementing a condition based maintenance system applying an open, modular and scalable integrated architecture to provide comprehensive solutions and support to the end users like operational and maintenance team. The system called SIMPREBAL (Predictive Maintenance System of Balbina) is advocate of open standards, in particular through collaborative research programmers. In the developing is clearly understands the need for both, industry standards and a simple to use software development tool chain, supporting the development of complex condition based maintenance systems with multiple partners. The Open System Architecture for Condition Based Maintenance (OSA-CBM) is a standard that consider seven hierarchic layers that represent a logic transition or performed data flow from the data acquisition layer, through the intermediates layers as signal processing, condition monitor, health assessment, prognostics and decision support, to arrive to the presentation layer. SIMPREBAL is being implementing as an OSA-CBM software framework and tool set that allows the creation of truly integrated, comprehensive maintenance solutions through the internet. This paper identifies specific benefits of the application of the OSA-CBM in comprehensive solutions of condition based maintenance for a hydroelectric power plant. (author)

Applications of computer based safety systems in Korea nuclear power plants

International Nuclear Information System (INIS)

Won Young Yun

1998-01-01

With the progress of computer technology, the applications of computer based safety systems in Korea nuclear power plants have increased rapidly in recent decades. The main purpose of this movement is to take advantage of modern computer technology so as to improve the operability and maintainability of the plants. However, in fact there have been a lot of controversies on computer based systems' safety between the regulatory body and nuclear utility in Korea. The Korea Institute of Nuclear Safety (KINS), technical support organization for nuclear plant licensing, is currently confronted with the pressure to set up well defined domestic regulatory requirements from this aspect. This paper presents the current status and the regulatory activities related to the applications of computer based safety systems in Korea. (author)

ESB-Based Sensor Web Integration for the Prediction of Electric Power Supply System Vulnerability

Directory of Open Access Journals (Sweden)

Milos Bogdanovic

2013-08-01

Full Text Available Electric power supply companies increasingly rely on enterprise IT systems to provide them with a comprehensive view of the state of the distribution network. Within a utility-wide network, enterprise IT systems collect data from various metering devices. Such data can be effectively used for the prediction of power supply network vulnerability. The purpose of this paper is to present the Enterprise Service Bus (ESB-based Sensor Web integration solution that we have developed with the purpose of enabling prediction of power supply network vulnerability, in terms of a prediction of defect probability for a particular network element. We will give an example of its usage and demonstrate our vulnerability prediction model on data collected from two different power supply companies. The proposed solution is an extension of the GinisSense Sensor Web-based architecture for collecting, processing, analyzing, decision making and alerting based on the data received from heterogeneous data sources. In this case, GinisSense has been upgraded to be capable of operating in an ESB environment and combine Sensor Web and GIS technologies to enable prediction of electric power supply system vulnerability. Aside from electrical values, the proposed solution gathers ambient values from additional sensors installed in the existing power supply network infrastructure. GinisSense aggregates gathered data according to an adapted Omnibus data fusion model and applies decision-making logic on the aggregated data. Detected vulnerabilities are visualized to end-users through means of a specialized Web GIS application.

ESB-based Sensor Web integration for the prediction of electric power supply system vulnerability.

Science.gov (United States)

Stoimenov, Leonid; Bogdanovic, Milos; Bogdanovic-Dinic, Sanja

2013-08-15

Electric power supply companies increasingly rely on enterprise IT systems to provide them with a comprehensive view of the state of the distribution network. Within a utility-wide network, enterprise IT systems collect data from various metering devices. Such data can be effectively used for the prediction of power supply network vulnerability. The purpose of this paper is to present the Enterprise Service Bus (ESB)-based Sensor Web integration solution that we have developed with the purpose of enabling prediction of power supply network vulnerability, in terms of a prediction of defect probability for a particular network element. We will give an example of its usage and demonstrate our vulnerability prediction model on data collected from two different power supply companies. The proposed solution is an extension of the GinisSense Sensor Web-based architecture for collecting, processing, analyzing, decision making and alerting based on the data received from heterogeneous data sources. In this case, GinisSense has been upgraded to be capable of operating in an ESB environment and combine Sensor Web and GIS technologies to enable prediction of electric power supply system vulnerability. Aside from electrical values, the proposed solution gathers ambient values from additional sensors installed in the existing power supply network infrastructure. GinisSense aggregates gathered data according to an adapted Omnibus data fusion model and applies decision-making logic on the aggregated data. Detected vulnerabilities are visualized to end-users through means of a specialized Web GIS application.

ESB-Based Sensor Web Integration for the Prediction of Electric Power Supply System Vulnerability

Science.gov (United States)

Stoimenov, Leonid; Bogdanovic, Milos; Bogdanovic-Dinic, Sanja

2013-01-01

Electric power supply companies increasingly rely on enterprise IT systems to provide them with a comprehensive view of the state of the distribution network. Within a utility-wide network, enterprise IT systems collect data from various metering devices. Such data can be effectively used for the prediction of power supply network vulnerability. The purpose of this paper is to present the Enterprise Service Bus (ESB)-based Sensor Web integration solution that we have developed with the purpose of enabling prediction of power supply network vulnerability, in terms of a prediction of defect probability for a particular network element. We will give an example of its usage and demonstrate our vulnerability prediction model on data collected from two different power supply companies. The proposed solution is an extension of the GinisSense Sensor Web-based architecture for collecting, processing, analyzing, decision making and alerting based on the data received from heterogeneous data sources. In this case, GinisSense has been upgraded to be capable of operating in an ESB environment and combine Sensor Web and GIS technologies to enable prediction of electric power supply system vulnerability. Aside from electrical values, the proposed solution gathers ambient values from additional sensors installed in the existing power supply network infrastructure. GinisSense aggregates gathered data according to an adapted Omnibus data fusion model and applies decision-making logic on the aggregated data. Detected vulnerabilities are visualized to end-users through means of a specialized Web GIS application. PMID:23955435

3-Coil resonance-based wireless power transfer system for implantable electronic

KAUST Repository

Yi, Ying; Buttner, Ulrich; Fan, Yiqiang; Foulds, Ian G.

2013-01-01

This paper presents a 3-coil resonance-based wireless power transfer (R-WPT) system using a single layer of inductor coil windings, in a pancake configuration, in order to obtain a compact system for implantable electronic applications. A theoretical analysis and experimental measurements in terms of quality factor Q and power transfer efficiency (PTE), was done. Our proposed 3-coil scheme can achieve a high PTE with a resonance frequency of 2.46 MHz over a transfer distance of up to 30 mm, by using two 15-mm radius implant coils. The achieved experimental PTE is more than 85%at a 5 mm separation distance, and about 50% PTE at a distance of 20 mm. © 2013 IEEE.

3-Coil resonance-based wireless power transfer system for implantable electronic

KAUST Repository

Yi, Ying

2013-05-01

This paper presents a 3-coil resonance-based wireless power transfer (R-WPT) system using a single layer of inductor coil windings, in a pancake configuration, in order to obtain a compact system for implantable electronic applications. A theoretical analysis and experimental measurements in terms of quality factor Q and power transfer efficiency (PTE), was done. Our proposed 3-coil scheme can achieve a high PTE with a resonance frequency of 2.46 MHz over a transfer distance of up to 30 mm, by using two 15-mm radius implant coils. The achieved experimental PTE is more than 85%at a 5 mm separation distance, and about 50% PTE at a distance of 20 mm. © 2013 IEEE.

Wind Power Fluctuation Smoothing Controller Based on Risk Assessment of Grid Frequency Deviation in an Isolated System

DEFF Research Database (Denmark)

Lin, Jin; Sun, Yuanzhang; Song, Yonghua

2013-01-01

a smoothing controller to suppress the power fluctuation from doubly-fed induction generator (DFIG)-based wind farm. This controller consists of threemain functionality components: risk assessmentmodel, wind turbine rotor speed optimizer, and rotor speed upper limiter. In order to avoid unnecessary energy...... curve with reduced output so that a trade-off between fluctuation smoothing and energy loss is achieved. Subsequently, the controller limits the maximum rotor speed to shift down the power curve of wind power plant based on the optimal wind turbine rotor speed. Therefore, the power fluctuation......Wind power fluctuation raises the security concern of grid frequency deviation, especially for an isolated power system. Thus, better control methodology needs to be developed to smooth the fluctuation without excessive spillage. Based on an actual industrial power system, this paper proposes...

Equivalent modeling of PMSG-based wind power plants considering LVRT capabilities: electromechanical transients in power systems.

Science.gov (United States)

Ding, Ming; Zhu, Qianlong

2016-01-01

Hardware protection and control action are two kinds of low voltage ride-through technical proposals widely used in a permanent magnet synchronous generator (PMSG). This paper proposes an innovative clustering concept for the equivalent modeling of a PMSG-based wind power plant (WPP), in which the impacts of both the chopper protection and the coordinated control of active and reactive powers are taken into account. First, the post-fault DC link voltage is selected as a concentrated expression of unit parameters, incoming wind and electrical distance to a fault point to reflect the transient characteristics of PMSGs. Next, we provide an effective method for calculating the post-fault DC link voltage based on the pre-fault wind energy and the terminal voltage dip. Third, PMSGs are divided into groups by analyzing the calculated DC link voltages without any clustering algorithm. Finally, PMSGs of the same group are equivalent as one rescaled PMSG to realize the transient equivalent modeling of the PMSG-based WPP. Using the DIgSILENT PowerFactory simulation platform, the efficiency and accuracy of the proposed equivalent model are tested against the traditional equivalent WPP and the detailed WPP. The simulation results show the proposed equivalent model can be used to analyze the offline electromechanical transients in power systems.

Diversification criteria for power systems

International Nuclear Information System (INIS)

Kharbach, Mohammed

2016-01-01

Growing power demand, fuel availability and prices, technology changes, the environmental impacts of energy consumption, the changing regulatory environments and the uncertainties around such elements make the planning for optimal power mix a challenging task. The diversity approach is advocated as a most appropriate planning methodology for the optimal energy mix (Hickey et al., 2010). Shannon Wiener Index (SWI), which is the most cited diversity metric has been used to assess power systems diversity mainly from an energy perspective. To our best knowledge, there is no rigorous justification why energy has been the main variable used in diversification exercises rather than other variables such as capacity. We use a stylized power generation framework to show that diversity based on energy or capacity could lead to different outcomes in terms of vulnerability to fuel exposure, among others. We also introduce a Shannon Wiener Index ratio (SWIR) that we believe captures better the diversity of a power system compared to the standard SWI. - Highlights: • Ranking power systems, from a diversity perspective, based on one criteria has many shortcomings. • Diversity based on energy or capacity could lead to different outcomes in terms of vulnerability to fuel exposure, among others. • A Shannon Wiener Index ratio (SWIR) captures better the diversity of a power system compared to the standard SWI.

Power Electronics in Wind Turbine Systems

DEFF Research Database (Denmark)

Blaabjerg, Frede; Chen, Zhe; Teodorescu, Remus

2006-01-01

the conventional, fossil (and short term) based energy sources to renewable energy resources. The other is to use high efficient power electronics in power systems, power production and end-user application. This paper discuss the most emerging renewable energy source, wind energy, which by means of power...... electronics is changing from being a minor energy source to be acting as an important power source in the energy system. By that wind power is also getting an added value in the power system operation....

Design of Electric Power Management System in Jilin Province based on SOA

Directory of Open Access Journals (Sweden)

Ren Shou Ze

2016-01-01

Full Text Available Aiming at the problem of electric power data integration and sharing in Jilin Province, China, this paper proposed a method based on SOA which has high scalability, flexibility in strong power data and application integration. This approach establishes a web service-oriented system architecture, using SQL Server 2012 as its backend database and using C# as the programming language. And this approach has developed three kinds of terminal applications namely C/S(Client/Server, B/S(Browser /Server and M/S(Mobile/Server. Client applications send all kinds of request to the electric power cloud computing centre, meanwhile web service components receive the requests and call corresponding functions to compute, and then return the results to the original app through the internet. The results show that system achieved the target we expected and successfully realized electric power information data integration, release and sharing.

The Optimization of power reactor control system

International Nuclear Information System (INIS)

Danupoyo, S.D.

1997-01-01

A power reactor is an important part in nuclear powered electrical plant systems. Success in controlling the power reactor will establish safety of the whole power plant systems. Until now, the power reactor has been controlled by a classical control system that was designed based on output feedback method. To meet the safety requirements that are now more restricted, the recently used power reactor control system should be modified. this paper describes a power reactor control system that is designed based on a state feedback method optimized with LQG (Linear-quadrature-gaussian) method and equipped with a state estimator. A pressurized-water type reactor has been used as the model. by using a point kinetics method with one group delayed neutrons. the result of simulation testing shows that the optimized control system can control the power reactor more effective and efficient than the classical control system

Economical Efficiency of Combined Cooling Heating and Power Systems Based on an Enthalpy Method

Directory of Open Access Journals (Sweden)

Yan Xu

2017-11-01

Full Text Available As the living standards of Chinese people have been improving, the energy demand for cooling and heating, mainly in the form of electricity, has also expanded. Since an integrated cooling, heating and power supply system (CCHP will serve this demand better, the government is now attaching more importance to the application of CCHP energy systems. Based on the characteristics of the combined cooling heating and power supply system, and the method of levelized cost of energy, two calculation methods for the evaluation of the economical efficiency of the system are employed when the energy production in the system is dealt with from the perspective of exergy. According to the first method, fuel costs account for about 75% of the total cost. In the second method, the profits from heating and cooling are converted to fuel costs, resulting in a significant reduction of fuel costs, accounting for 60% of the total cost. Then the heating and cooling parameters of gas turbine exhaust, heat recovery boiler, lithium-bromide heat-cooler and commercial tariff of provincial capitals were set as benchmark based on geographic differences among provinces, and the economical efficiency of combined cooling heating and power systems in each province were evaluated. The results shows that the combined cooling heating and power system is economical in the developed areas of central and eastern China, especially in Hubei and Zhejiang provinces, while in other regions it is not. The sensitivity analysis was also made on related influencing factors of fuel cost, demand intensity in heating and cooling energy, and bank loans ratio. The analysis shows that the levelized cost of energy of combined cooling heating and power systems is very sensitive to exergy consumption and fuel costs. When the consumption of heating and cooling energy increases, the unit cost decreases by 0.1 yuan/kWh, and when the on-grid power ratio decreases by 20%, the cost may increase by 0.1 yuan

Research on the Application of Risk-based Inspection for the Boiler System in Power Plant

Science.gov (United States)

Li, Henan

2017-12-01

Power plant boiler is one of the three main equipment of coal-fired power plants, is very tall to the requirement of the safe and stable operation, in a significant role in the whole system of thermal power generation, a risk-based inspection is a kind of pursuit of security and economy of unified system management idea and method, can effectively evaluate equipment risk and reduce the operational cost.

Power system voltage stability and agent based distribution automation in smart grid

Science.gov (United States)

Nguyen, Cuong Phuc

2011-12-01

Our interconnected electric power system is presently facing many challenges that it was not originally designed and engineered to handle. The increased inter-area power transfers, aging infrastructure, and old technologies, have caused many problems including voltage instability, widespread blackouts, slow control response, among others. These problems have created an urgent need to transform the present electric power system to a highly stable, reliable, efficient, and self-healing electric power system of the future, which has been termed "smart grid". This dissertation begins with an investigation of voltage stability in bulk transmission networks. A new continuation power flow tool for studying the impacts of generator merit order based dispatch on inter-area transfer capability and static voltage stability is presented. The load demands are represented by lumped load models on the transmission system. While this representation is acceptable in traditional power system analysis, it may not be valid in the future smart grid where the distribution system will be integrated with intelligent and quick control capabilities to mitigate voltage problems before they propagate into the entire system. Therefore, before analyzing the operation of the whole smart grid, it is important to understand the distribution system first. The second part of this dissertation presents a new platform for studying and testing emerging technologies in advanced Distribution Automation (DA) within smart grids. Due to the key benefits over the traditional centralized approach, namely flexible deployment, scalability, and avoidance of single-point-of-failure, a new distributed approach is employed to design and develop all elements of the platform. A multi-agent system (MAS), which has the three key characteristics of autonomy, local view, and decentralization, is selected to implement the advanced DA functions. The intelligent agents utilize a communication network for cooperation and

Power Management Based Current Control Technique for Photovoltaic-Battery Assisted Wind-Hydro Hybrid System

Science.gov (United States)

Ram Prabhakar, J.; Ragavan, K.

2013-07-01

This article proposes new power management based current control strategy for integrated wind-solar-hydro system equipped with battery storage mechanism. In this control technique, an indirect estimation of load current is done, through energy balance model, DC-link voltage control and droop control. This system features simpler energy management strategy and necessitates few power electronic converters, thereby minimizing the cost of the system. The generation-demand (G-D) management diagram is formulated based on the stochastic weather conditions and demand, which would likely moderate the gap between both. The features of management strategy deploying energy balance model include (1) regulating DC-link voltage within specified tolerances, (2) isolated operation without relying on external electric power transmission network, (3) indirect current control of hydro turbine driven induction generator and (4) seamless transition between grid-connected and off-grid operation modes. Furthermore, structuring of the hybrid system with appropriate selection of control variables enables power sharing among each energy conversion systems and battery storage mechanism. By addressing these intricacies, it is viable to regulate the frequency and voltage of the remote network at load end. The performance of the proposed composite scheme is demonstrated through time-domain simulation in MATLAB/Simulink environment.

Performance analysis of a lunar based solar thermal power system with regolith thermal storage

International Nuclear Information System (INIS)

Lu, Xiaochen; Ma, Rong; Wang, Chao; Yao, Wei

2016-01-01

The manned deep-space exploration is a hot topic of the current space activities. The continuous supply of thermal and electrical energy for the scientific equipment and human beings is a crucial issue for the lunar outposts. Since the night lasts for periods of about 350 h at most locations on the lunar surface, massive energy storage is required for continuous energy supply during the lengthy lunar night and the in-situ resource utilization is demanded. A lunar based solar thermal power system with regolith thermal storage is presented in this paper. The performance analysis is carried out by the finite-time thermodynamics to take into account major irreversible losses. The influences of some key design parameters are analyzed for system optimization. The analytical results shows that the lunar based solar thermal power system with regolith thermal storage can meet the requirement of the continuous energy supply for lunar outposts. - Highlights: • A lunar based solar thermal power system with regolith thermal storage is presented. • The performance analysis is carried out by the finite-time thermodynamics. • The influences of some key design parameters are analyzed.

Distributed Reactive Power Control based Conservation Voltage Reduction in Active Distribution Systems

Directory of Open Access Journals (Sweden)

EMIROGLU, S.

2017-11-01

Full Text Available This paper proposes a distributed reactive power control based approach to deploy Volt/VAr optimization (VVO / Conservation Voltage Reduction (CVR algorithm in a distribution network with distributed generations (DG units and distribution static synchronous compensators (D-STATCOM. A three-phase VVO/CVR problem is formulated and the reactive power references of D-STATCOMs and DGs are determined in a distributed way by decomposing the VVO/CVR problem into voltage and reactive power control. The main purpose is to determine the coordination between voltage regulator (VR and reactive power sources (Capacitors, D-STATCOMs and DGs based on VVO/CVR. The study shows that the reactive power injection capability of DG units may play an important role in VVO/CVR. In addition, it is shown that the coordination of VR and reactive power sources does not only save more energy and power but also reduces the power losses. Moreover, the proposed VVO/CVR algorithm reduces the computational burden and finds fast solutions. To illustrate the effectiveness of the proposed method, the VVO/CVR is performed on the IEEE 13-node test system feeder considering unbalanced loading and line configurations. The tests are performed taking the practical voltage-dependent load modeling and different customer types into consideration to improve accuracy.

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.

Electric Vehicles in Power Systems with 50% Wind Power Penetration

DEFF Research Database (Denmark)

Østergaard, Jacob; Foosnæs, Anders; Xu, Zhao

2009-01-01

will be an important balancing measure to enable the Danish government’s energy strategy, which implies 50% wind power penetration in the electric power system. An EV will be a storage device for smoothing power fluctuations from renewable resources especially wind power and provide valuable system services...... for a reliable power system operation. Cost-benefit analysis shows that intelligent bidirectional charging – vehicle to grid (V2G) – provides a socio-economic profit of 150 million Euro/year in the Danish electric power system in 2025 assuming that 15% of the Danish road transport need is supplied by electricity....... This paper analyse the potential for using EVs in Denmark and identify the benefits of the electric power system with high wind power generation by intelligent charging of the EVs. Based on the analysis important technology gabs are identified, and the corresponding research and development initiatives...

Powered Upper Limb Orthosis Actuation System Based on Pneumatic Artificial Muscles

Science.gov (United States)

Chakarov, Dimitar; Veneva, Ivanka; Tsveov, Mihail; Venev, Pavel

2018-03-01

The actuation system of a powered upper limb orthosis is studied in the work. To create natural safety in the mutual "man-robot" interaction, an actuation system based on pneumatic artificial muscles (PAM) is selected. Experimentally obtained force/contraction diagrams for bundles, consisting of different number of muscles are shown in the paper. The pooling force and the stiffness of the pneumatic actuators is assessed as a function of the number of muscles in the bundle and the supply pressure. Joint motion and torque is achieved by antagonistic actions through pulleys, driven by bundles of pneumatic muscles. Joint stiffness and joint torques are determined on condition of a power balance, as a function of the joint position, pressure, number of muscles and muscles

Cost-optimal power system extension under flow-based market coupling

Energy Technology Data Exchange (ETDEWEB)

Hagspiel, Simeon; Jaegemann, Cosima; Lindenberger, Dietmar [Koeln Univ. (Germany). Energiewirtschaftliches Inst.; Brown, Tom; Cherevatskiy, Stanislav; Troester, Eckehard [Energynautics GmbH, Langen (Germany)

2013-05-15

Electricity market models, implemented as dynamic programming problems, have been applied widely to identify possible pathways towards a cost-optimal and low carbon electricity system. However, the joint optimization of generation and transmission remains challenging, mainly due to the fact that different characteristics and rules apply to commercial and physical exchanges of electricity in meshed networks. This paper presents a methodology that allows to optimize power generation and transmission infrastructures jointly through an iterative approach based on power transfer distribution factors (PTDFs). As PTDFs are linear representations of the physical load flow equations, they can be implemented in a linear programming environment suitable for large scale problems. The algorithm iteratively updates PTDFs when grid infrastructures are modified due to cost-optimal extension and thus yields an optimal solution with a consistent representation of physical load flows. The method is first demonstrated on a simplified three-node model where it is found to be robust and convergent. It is then applied to the European power system in order to find its cost-optimal development under the prescription of strongly decreasing CO{sub 2} emissions until 2050.

A Dynamic Programming based method for optimizing power system restoration with high wind power penetration

DEFF Research Database (Denmark)

Hu, Rui; Hu, Weihao; Li, Pengfei

2016-01-01

and relatively low cost. Thus, many countries are increasing the wind power penetration in their power system step by step, such as Denmark, Spain and Germany. The incremental wind power penetration brings a lot of new issues in operation and programming. The power system sometimes will operate close to its...... stable limits. Once the blackout happens, a well-designed restoration strategy is significant. This paper focuses on how to ameliorate the power system restoration procedures to adapt the high wind power penetration and how to take full advantages of the wind power plants during the restoration....... In this paper, the possibility to exploit the stochastic wind power during restoration was discussed, and a Dynamic Programming (DP) method was proposed to make wind power contribute in the restoration rationally as far as possible. In this paper, the method is tested and verified by a modified IEEE 30 Buses...

Energy efficiency comparison between geothermal power systems

Directory of Open Access Journals (Sweden)

Luo Chao

2017-01-01

Full Text Available The geothermal water which can be considered for generating electricity with the temperature ranging from 80℃ to 150℃ in China because of shortage of electricity and fossil energy. There are four basic types of geothermal power systems: single flash, double flash, binary cycle, and flash-binary system, which can be adapted to geothermal energy utilization in China. The paper discussed the performance indices and applicable conditions of different power system. Based on physical and mathematical models, simulation result shows that, when geofluid temperature ranges from 100℃ to 130℃, the net power output of double flash power is bigger than flash-binary system. When the geothermal resource temperature is between 130℃ and 150℃, the net power output of flash-binary geothermal power system is higher than double flash system by the maximum value 5.5%. However, the sum water steam amount of double flash power system is 2 to 3 times larger than flash-binary power system, which will cause the bigger volume of equipment of power system. Based on the economy and power capacity, it is better to use flash-binary power system when the geofluid temperature is between 100℃ and 150℃.

A low power flash-FPGA based brain implant micro-system of PID control.

Science.gov (United States)

Lijuan Xia; Fattah, Nabeel; Soltan, Ahmed; Jackson, Andrew; Chester, Graeme; Degenaar, Patrick

2017-07-01

In this paper, we demonstrate that a low power flash FPGA based micro-system can provide a low power programmable interface for closed-loop brain implant inter- faces. The proposed micro-system receives recording local field potential (LFP) signals from an implanted probe, performs closed-loop control using a first order control system, then converts the signal into an optogenetic control stimulus pattern. Stimulus can be implemented through optoelectronic probes. The long term target is for both fundamental neuroscience applications and for clinical use in treating epilepsy. Utilizing our device, closed-loop processing consumes only 14nJ of power per PID cycle compared to 1.52μJ per cycle for a micro-controller implementation. Compared to an application specific digital integrated circuit, flash FPGA's are inherently programmable.

Software for computer based systems important to safety in nuclear power plants. Safety guide

International Nuclear Information System (INIS)

2004-01-01

Computer based systems are of increasing importance to safety in nuclear power plants as their use in both new and older plants is rapidly increasing. They are used both in safety related applications, such as some functions of the process control and monitoring systems, as well as in safety critical applications, such as reactor protection or actuation of safety features. The dependability of computer based systems important to safety is therefore of prime interest and should be ensured. With current technology, it is possible in principle to develop computer based instrumentation and control systems for systems important to safety that have the potential for improving the level of safety and reliability with sufficient dependability. However, their dependability can be predicted and demonstrated only if a systematic, fully documented and reviewable engineering process is followed. Although a number of national and international standards dealing with quality assurance for computer based systems important to safety have been or are being prepared, internationally agreed criteria for demonstrating the safety of such systems are not generally available. It is recognized that there may be other ways of providing the necessary safety demonstration than those recommended here. The basic requirements for the design of safety systems for nuclear power plants are provided in the Requirements for Design issued in the IAEA Safety Standards Series.The IAEA has issued a Technical Report to assist Member States in ensuring that computer based systems important to safety in nuclear power plants are safe and properly licensed. The report provides information on current software engineering practices and, together with relevant standards, forms a technical basis for this Safety Guide. The objective of this Safety Guide is to provide guidance on the collection of evidence and preparation of documentation to be used in the safety demonstration for the software for computer based

Software for computer based systems important to safety in nuclear power plants. Safety guide

International Nuclear Information System (INIS)

2005-01-01

Computer based systems are of increasing importance to safety in nuclear power plants as their use in both new and older plants is rapidly increasing. They are used both in safety related applications, such as some functions of the process control and monitoring systems, as well as in safety critical applications, such as reactor protection or actuation of safety features. The dependability of computer based systems important to safety is therefore of prime interest and should be ensured. With current technology, it is possible in principle to develop computer based instrumentation and control systems for systems important to safety that have the potential for improving the level of safety and reliability with sufficient dependability. However, their dependability can be predicted and demonstrated only if a systematic, fully documented and reviewable engineering process is followed. Although a number of national and international standards dealing with quality assurance for computer based systems important to safety have been or are being prepared, internationally agreed criteria for demonstrating the safety of such systems are not generally available. It is recognized that there may be other ways of providing the necessary safety demonstration than those recommended here. The basic requirements for the design of safety systems for nuclear power plants are provided in the Requirements for Design issued in the IAEA Safety Standards Series.The IAEA has issued a Technical Report to assist Member States in ensuring that computer based systems important to safety in nuclear power plants are safe and properly licensed. The report provides information on current software engineering practices and, together with relevant standards, forms a technical basis for this Safety Guide. The objective of this Safety Guide is to provide guidance on the collection of evidence and preparation of documentation to be used in the safety demonstration for the software for computer based

Software for computer based systems important to safety in nuclear power plants. Safety guide

International Nuclear Information System (INIS)

2000-01-01

Computer based systems are of increasing importance to safety in nuclear power plants as their use in both new and older plants is rapidly increasing. They are used both in safety related applications, such as some functions of the process control and monitoring systems, as well as in safety critical applications, such as reactor protection or actuation of safety features. The dependability of computer based systems important to safety is therefore of prime interest and should be ensured. With current technology, it is possible in principle to develop computer based instrumentation and control systems for systems important to safety that have the potential for improving the level of safety and reliability with sufficient dependability. However, their dependability can be predicted and demonstrated only if a systematic, fully documented and reviewable engineering process is followed. Although a number of national and international standards dealing with quality assurance for computer based systems important to safety have been or are being prepared, internationally agreed criteria for demonstrating the safety of such systems are not generally available. It is recognized that there may be other ways of providing the necessary safety demonstration than those recommended here. The basic requirements for the design of safety systems for nuclear power plants are provided in the Requirements for Design issued in the IAEA Safety Standards Series.The IAEA has issued a Technical Report to assist Member States in ensuring that computer based systems important to safety in nuclear power plants are safe and properly licensed. The report provides information on current software engineering practices and, together with relevant standards, forms a technical basis for this Safety Guide. The objective of this Safety Guide is to provide guidance on the collection of evidence and preparation of documentation to be used in the safety demonstration for the software for computer based

Design and Tuning of a Modified Power-Based PLL for Single-Phase Grid-Connected Power Conditioning Systems

DEFF Research Database (Denmark)

Golestan, Saeed; Monfared, Mohammad; D. Freijedo, Francisco

2012-01-01

One of the most important aspects for the proper operation of the single-phase grid-tied power-conditioning systems is the synchronization with the utility grid. Among various synchronization techniques, phase locked loop (PLL) based algorithms have found a lot of interest for the advantages...

Application of PMU-Based Information in the Indian Power System

Science.gov (United States)

Agarwal, P. K.; Agarwal, V. K.; Rathour, Harish

2013-05-01

SCADA/EMS system has been the most commonly used tool for real-time power system operation and control throughout the world. This system has been found to be very useful in steady-state analysis of the power system. The ever-increasing dependence of human society and every country's economy on electrical energy calls for reliable power delivery. In order to meet these expectations, engineers across the globe have been exploring such new technologies that can improve upon the limitations of SCADA and provide dynamic visibility of the power system. A breakthrough has now been achieved in the form of synchrophasor technology. Synchrophasor measurements using phasor measurement units (PMUs) deployed over a wide area, facilitate dynamic state measurement and visualization of a power system, which are useful in monitoring safety and security of the grid. The Power System Operation Corporation (POSOCO) has taken initiative and implemented a pilot project wherein nine phasor measurement units (PMUs) along with one phasor data concentrator (PDC) were commissioned in the Northern Region (NR) of India. The primary objective of this pilot project was to comprehend the synchrophasor technology and its applications in power system operation. The data received and information derived from the pilot project have been found to be very useful and helped in improving the performance of the grid operation in several ways. The pilot project is operational for the last two years; in the meanwhile, many other initiatives have also been taken in other regions by POSOCO. This article details the utilization of the data collected from the pilot projects and the application of the data in the improvement of Indian power grid.

Application of chaos-based chaotic invasive weed optimization techniques for environmental OPF problems in the power system

International Nuclear Information System (INIS)

Ghasemi, Mojtaba; Ghavidel, Sahand; Aghaei, Jamshid; Gitizadeh, Mohsen; Falah, Hasan

2014-01-01

Highlights: • Chaotic invasive weed optimization techniques based on chaos. • Nonlinear environmental OPF problem considering non-smooth fuel cost curves. • A comparative study of CIWO techniques for environmental OPF problem. - Abstract: This paper presents efficient chaotic invasive weed optimization (CIWO) techniques based on chaos for solving optimal power flow (OPF) problems with non-smooth generator fuel cost functions (non-smooth OPF) with the minimum pollution level (environmental OPF) in electric power systems. OPF problem is used for developing corrective strategies and to perform least cost dispatches. However, cost based OPF problem solutions usually result in unattractive system gaze emission issue (environmental OPF). In the present paper, the OPF problem is formulated by considering the emission issue. The total emission can be expressed as a non-linear function of power generation, as a multi-objective optimization problem, where optimal control settings for simultaneous minimization of fuel cost and gaze emission issue are obtained. The IEEE 30-bus test power system is presented to illustrate the application of the environmental OPF problem using CIWO techniques. Our experimental results suggest that CIWO techniques hold immense promise to appear as efficient and powerful algorithm for optimization in the power systems

Operation Modeling of Power Systems Integrated with Large-Scale New Energy Power Sources

Directory of Open Access Journals (Sweden)

Hui Li

2016-10-01

Full Text Available In the most current methods of probabilistic power system production simulation, the output characteristics of new energy power generation (NEPG has not been comprehensively considered. In this paper, the power output characteristics of wind power generation and photovoltaic power generation are firstly analyzed based on statistical methods according to their historical operating data. Then the characteristic indexes and the filtering principle of the NEPG historical output scenarios are introduced with the confidence level, and the calculation model of NEPG’s credible capacity is proposed. Based on this, taking the minimum production costs or the best energy-saving and emission-reduction effect as the optimization objective, the power system operation model with large-scale integration of new energy power generation (NEPG is established considering the power balance, the electricity balance and the peak balance. Besides, the constraints of the operating characteristics of different power generation types, the maintenance schedule, the load reservation, the emergency reservation, the water abandonment and the transmitting capacity between different areas are also considered. With the proposed power system operation model, the operation simulations are carried out based on the actual Northwest power grid of China, which resolves the new energy power accommodations considering different system operating conditions. The simulation results well verify the validity of the proposed power system operation model in the accommodation analysis for the power system which is penetrated with large scale NEPG.

TCSC robust damping controller design based on particle swarm optimization for a multi-machine power system

Energy Technology Data Exchange (ETDEWEB)

Shayeghi, H., E-mail: hshayeghi@gmail.co [Technical Engineering Department, University of Mohaghegh Ardabili, Ardabil (Iran, Islamic Republic of); Shayanfar, H.A. [Center of Excellence for Power System Automation and Operation, Electrical Engineering Department, Iran University of Science and Technology, Tehran (Iran, Islamic Republic of); Jalilzadeh, S.; Safari, A. [Technical Engineering Department, Zanjan University, Zanjan (Iran, Islamic Republic of)

2010-10-15

In this paper, a new approach based on the particle swarm optimization (PSO) technique is proposed to tune the parameters of the thyristor controlled series capacitor (TCSC) power oscillation damping controller. The design problem of the damping controller is converted to an optimization problem with the time-domain-based objective function which is solved by a PSO technique which has a strong ability to find the most optimistic results. To ensure the robustness of the proposed stabilizers, the design process takes a wide range of operating conditions into account. The performance of the newly designed controller is evaluated in a four-machine power system subjected to the different types of disturbances in comparison with the genetic algorithm based damping controller. The effectiveness of the proposed controller is demonstrated through the nonlinear time-domain simulation and some performance indices studies. The results analysis reveals that the tuned PSO based TCSC damping controller using the proposed fitness function has an excellent capability in damping power system inter-area oscillations and enhances greatly the dynamic stability of the power systems. Moreover, it is superior to the genetic algorithm based damping controller.

Robust Power Management Control for Stand-Alone Hybrid Power Generation System

International Nuclear Information System (INIS)

Kamal, Elkhatib; Adouane, Lounis; Aitouche, Abdel; Mohammed, Walaa

2017-01-01

This paper presents a new robust fuzzy control of energy management strategy for the stand-alone hybrid power systems. It consists of two levels named centralized fuzzy supervisory control which generates the power references for each decentralized robust fuzzy control. Hybrid power systems comprises: a photovoltaic panel and wind turbine as renewable sources, a micro turbine generator and a battery storage system. The proposed control strategy is able to satisfy the load requirements based on a fuzzy supervisor controller and manage power flows between the different energy sources and the storage unit by respecting the state of charge and the variation of wind speed and irradiance. Centralized controller is designed based on If-Then fuzzy rules to manage and optimize the hybrid power system production by generating the reference power for photovoltaic panel and wind turbine. Decentralized controller is based on the Takagi-Sugeno fuzzy model and permits us to stabilize each photovoltaic panel and wind turbine in presence of disturbances and parametric uncertainties and to optimize the tracking reference which is given by the centralized controller level. The sufficient conditions stability are formulated in the format of linear matrix inequalities using the Lyapunov stability theory. The effectiveness of the proposed Strategy is finally demonstrated through a SAHPS (stand-alone hybrid power systems) to illustrate the effectiveness of the overall proposed method. (paper)

BENCHMARKING THE OPTICAL RESOLVING POWER OF UAV BASED CAMERA SYSTEMS

Directory of Open Access Journals (Sweden)

H. Meißner

2017-08-01

Full Text Available UAV based imaging and 3D object point generation is an established technology. Some of the UAV users try to address (very highaccuracy applications, i.e. inspection or monitoring scenarios. In order to guarantee such level of detail and accuracy high resolving imaging systems are mandatory. Furthermore, image quality considerably impacts photogrammetric processing, as the tie point transfer, mandatory for forming the block geometry, fully relies on the radiometric quality of images. Thus, empirical testing of radiometric camera performance is an important issue, in addition to standard (geometric calibration, which normally is covered primarily. Within this paper the resolving power of ten different camera/lens installations has been investigated. Selected systems represent different camera classes, like DSLRs, system cameras, larger format cameras and proprietary systems. As the systems have been tested in wellcontrolled laboratory conditions and objective quality measures have been derived, individual performance can be compared directly, thus representing a first benchmark on radiometric performance of UAV cameras. The results have shown, that not only the selection of appropriate lens and camera body has an impact, in addition the image pre-processing, i.e. the use of a specific debayering method, significantly influences the final resolving power.

An Optimal Reactive Power Control Strategy for a DFIG-Based Wind Farm to Damp the Sub-Synchronous Oscillation of a Power System

Directory of Open Access Journals (Sweden)

Bin Zhao

2014-05-01

Full Text Available This study presents the auxiliary damping control with the reactive power loop on the rotor-side converter of doubly-fed induction generator (DFIG-based wind farms to depress the sub-synchronous resonance oscillations in nearby turbogenerators. These generators are connected to a series capacitive compensation transmission system. First, the damping effect of the reactive power control of the DFIG-based wind farms was theoretically analyzed, and a transfer function between turbogenerator speed and the output reactive power of the wind farms was introduced to derive the analytical expression of the damping coefficient. The phase range to obtain positive damping was determined. Second, the PID phase compensation parameters of the auxiliary damping controller were optimized by a genetic algorithm to obtain the optimum damping in the entire subsynchronous frequency band. Finally, the validity and effectiveness of the proposed auxiliary damping control were demonstrated on a modified version of the IEEE first benchmark model by time domain simulation analysis with the use of DigSILENT/PowerFactory. Theoretical analysis and simulation results show that this derived damping factor expression and the condition of the positive damping can effectively analyze their impact on the system sub-synchronous oscillations, the proposed wind farms reactive power additional damping control strategy can provide the optimal damping effect over the whole sub-synchronous frequency band, and the control effect is better than the active power additional damping control strategy based on the power system stabilizator.

High Frequency Resonance Damping of DFIG based Wind Power System under Weak Network

DEFF Research Database (Denmark)

Song, Yipeng; Wang, Xiongfei; Blaabjerg, Frede

2017-01-01

When operating in a micro or weak grid which has a relatively large network impedance, the Doubly Fed Induction Generator (DFIG) based wind power generation system is prone to suffer high frequency resonance due to the impedance interaction between DFIG system and the parallel compensated network...

An investigation of an uninterruptible power supply (UPS) based on supercapacitor and liquid nitrogen hybridization system

International Nuclear Information System (INIS)

Zhang, Xinjing; Xue, Haobai; Xu, Yujie; Chen, Haisheng; Tan, Chunqing

2014-01-01

Highlights: • A hybrid UPS based on supercapacitor and liquid nitrogen engine is proposed. • The dynamic modelling of the hybrid UPS system is conducted. • The dynamic working performance is obtained and analysed based on the simulation. • The hybrid UPS enjoys environmental benignity, long life and easy maintenance. • It is a highly possible solution to replace conventional UPS systems. - Abstract: An uninterruptible power supply (UPS) system based on supercapacitor and liquid nitrogen (LN 2 ) hybridization is first introduced in this paper. Of the newly designed UPS, the supercapacitor reacts instantaneously once the main supply fails, and it also starts the LN 2 power system to produce continuing electricity for the customer. This hybrid UPS system is of environment cleanness, long life time, easy maintenaince, etc. A 10 kW model is analyzed in this study. A two-stage nitrogen expander is designed with the rated speed of 900 rpm as the long time power generation device of the LN 2 cycle. The UPS starting process calculation is carried out. The results reveal that commercial supercapacitors could fulfill this request. This UPS could be a competent choice for the UPS application. Further discussion indicates the LN 2 power system could be used widely from UPS to low carbon vehicles

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.

Hydro power flexibility for power systems with variable renewable energy sources: an IEA Task 25 collaboration: Hydro power flexibility for power systems

Energy Technology Data Exchange (ETDEWEB)

Huertas-Hernando, Daniel [Department of Energy Systems, SINTEF, Trondheim Norway; Farahmand, Hossein [Department of Electric Power Engineering, Norwegian University of Science and Technology (NTNU), Trondheim Norway; Holttinen, Hannele [Department of Energy Systems, VTT Technical Research Centre of Finland, Espoo Finland; Kiviluoma, Juha [Department of Energy Systems, VTT Technical Research Centre of Finland, Espoo Finland; Rinne, Erkka [Department of Energy Systems, VTT Technical Research Centre of Finland, Espoo Finland; Söder, Lennart [Department of Electrical Engineering, KTH University, Stockholm Sweden; Milligan, Michael [Transmission and Grid Integration Group, National Renewable Energy Laboratory' s National Wind Technology Center, Golden CO USA; Ibanez, Eduardo [Transmission and Grid Integration Group, National Renewable Energy Laboratory' s National Wind Technology Center, Golden CO USA; Martínez, Sergio Martín [Department of Electrical Engineering, Electronics, Automation and Communications, Universidad de Castilla-La Mancha, Albacete Spain; Gomez-Lazaro, Emilio [Department of Electrical Engineering, Electronics, Automation and Communications, Universidad de Castilla-La Mancha, Albacete Spain; Estanqueiro, Ana [National Laboratory of Energy and Geology - LNEG, Lisbon Portugal; Rodrigues, Luis [National Laboratory of Energy and Geology - LNEG, Lisbon Portugal; Carr, Luis [Research Association for Energy Economics (FfE GmbH), Munich Germany; van Roon, Serafin [Research Association for Energy Economics (FfE GmbH), Munich Germany; Orths, Antje Gesa [Energinet.dk, Fredericia Denmark; Eriksen, Peter Børre [Energinet.dk, Fredericia Denmark; Forcione, Alain [Hydro Quebec, Montréal Canada; Menemenlis, Nickie [Hydro Quebec, Montréal Canada

2016-06-20

Hydro power is one of the most flexible sources of electricity production. Power systems with considerable amounts of flexible hydro power potentially offer easier integration of variable generation, e.g., wind and solar. However, there exist operational constraints to ensure mid-/long-term security of supply while keeping river flows and reservoirs levels within permitted limits. In order to properly assess the effective available hydro power flexibility and its value for storage, a detailed assessment of hydro power is essential. Due to the inherent uncertainty of the weather-dependent hydrological cycle, regulation constraints on the hydro system, and uncertainty of internal load as well as variable generation (wind and solar), this assessment is complex. Hence, it requires proper modeling of all the underlying interactions between hydro power and the power system, with a large share of other variable renewables. A summary of existing experience of wind integration in hydro-dominated power systems clearly points to strict simulation methodologies. Recommendations include requirements for techno-economic models to correctly assess strategies for hydro power and pumped storage dispatch. These models are based not only on seasonal water inflow variations but also on variable generation, and all these are in time horizons from very short term up to multiple years, depending on the studied system. Another important recommendation is to include a geographically detailed description of hydro power systems, rivers' flows, and reservoirs as well as grid topology and congestion.

Power supply system on HT-7 tokamak for diagnostic neutral beam based on PLC

International Nuclear Information System (INIS)

Zhang Jian; Liu Baohua; Ding Tonghai; Du Shaowu

2006-01-01

A power supply system for diagnostic neutral beam on the HT-7 Tokamak was developed. Its logic control system based on S7-300 PLC was described. The experimental results show that the system is easy to operate and its performance is reliable. (authors)

Power system dynamic state estimation using prediction based evolutionary technique

International Nuclear Information System (INIS)

Basetti, Vedik; Chandel, Ashwani K.; Chandel, Rajeevan

2016-01-01

In this paper, a new robust LWS (least winsorized square) estimator is proposed for dynamic state estimation of a power system. One of the main advantages of this estimator is that it has an inbuilt bad data rejection property and is less sensitive to bad data measurements. In the proposed approach, Brown's double exponential smoothing technique has been utilised for its reliable performance at the prediction step. The state estimation problem is solved as an optimisation problem using a new jDE-self adaptive differential evolution with prediction based population re-initialisation technique at the filtering step. This new stochastic search technique has been embedded with different state scenarios using the predicted state. The effectiveness of the proposed LWS technique is validated under different conditions, namely normal operation, bad data, sudden load change, and loss of transmission line conditions on three different IEEE test bus systems. The performance of the proposed approach is compared with the conventional extended Kalman filter. On the basis of various performance indices, the results thus obtained show that the proposed technique increases the accuracy and robustness of power system dynamic state estimation performance. - Highlights: • To estimate the states of the power system under dynamic environment. • The performance of the EKF method is degraded during anomaly conditions. • The proposed method remains robust towards anomalies. • The proposed method provides precise state estimates even in the presence of anomalies. • The results show that prediction accuracy is enhanced by using the proposed model.

Vehicle-to-Grid Power in Danish Electric Power Systems

DEFF Research Database (Denmark)

Pillai, Jayakrishnan Radhakrishna; Bak-Jensen, Birgitte

2009-01-01

The integration of renewable energy systems is often constrained by the variable nature of their output. This demands for the services of storing the electricity generated from most of the renewable energy sources. Vehicle-to-grid (V2G) power could use the inherent energy storage of electric...... vehicles and its quick response time to balance and stabilize a power system with fluctuating power. This paper outlines the use of battery electric vehicles in supporting large-scale integration of renewable energy in the Danish electric power systems. The reserve power requirements for a high renewable...... energy penetration could be met by an amount of V2G based electric vehicles less than 10% of the total vehicle need in Denmark. The participation of electric vehicle in ancillary services would earn significant revenues to the vehicle owner. The power balancing services of electric vehicles...

Design of a requirements system for decommissioning of a nuclear power plant based on systems engineering

Energy Technology Data Exchange (ETDEWEB)

Park, Hee Seong; Park, Seung Kook; Jin, Hyung Gon; Song, Chan Ho; Choi, Jong won [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2015-10-15

The nuclear industry has required an advanced system that can manage decommissioning information ever since the Korean government decide to decommission the Gori No.1 nuclear power plant. The D and D division at KAERI has been developing a system that can secure the reliability and sustainability of the decommissioning project based on the engineering system of the KRR-2 (Korean Research Reactor-2). To establish a decommissioning information system, a WBS that needs to be managed for the decommissioning of an NPP has been extracted, and requirements management research composed of system engineering technology has progressed. This paper propose a new type of system based on systems engineering technology. Even though a decommissioning engineering system was developed through the KRR-2, we are now developing an advanced decommissioning information system because it is not easy to apply this system to a commercial nuclear power plant. An NPP decommissioning is a project requiring a high degree of safety and economic feasibility. Therefore, we have to use a systematic project management at the initial phase of the decommissioning. An advanced system can manage the decommissioning information from preparation to remediation by applying a previous system to the systems engineering technology that has been widely used in large-scale government projects. The first phase of the system has progressed the requirements needed for a decommissioning project for a full life cycle. The defined requirements will be used in various types of documents during the decommissioning preparation phase.

Model based design of efficient power take-off systems for wave energy converters

DEFF Research Database (Denmark)

Hansen, Rico Hjerm; Andersen, Torben Ole; Pedersen, Henrik C.

2011-01-01

The Power Take-Off (PTO) is the core of a Wave Energy Converter (WECs), being the technology converting wave induced oscillations from mechanical energy to electricity. The induced oscillations are characterized by being slow with varying frequency and amplitude. Resultantly, fluid power is often...... an essential part of the PTO, being the only technology having the required force densities. The focus of this paper is to show the achievable efficiency of a PTO system based on a conventional hydro-static transmission topology. The design is performed using a model based approach. Generic component models...

A New Power System Restoration Technique based on WAMS Partitioning

Directory of Open Access Journals (Sweden)

N. V. Phanendra Babu

2017-08-01

Full Text Available An important feature of a Wide-Area Measurement System (WAMS is the ability to recover data during a communication failure. This paper presents a novel scheme of partitioning a PMU installed power network into a number of WAMS regions in order to make the power system restoration process simpler. This algorithm also proposes the optimal placement of Phasor Data Concentrators (PDCs in each region to record the data from PMUs. This paper considers the restoration constraints like transformer equivalent bus, generation-load balance and the observability of region for the partitioning of power system. The proposed scheme is demonstrated with an IEEE-30 bus system. It is then applied on IEEE-39, IEEE-118 bus systems and on a Northern Regional Grid of the Indian Power Grid.

Performance characterization of a power generation unit–organic Rankine cycle system based on the efficiencies of the system components

International Nuclear Information System (INIS)

Knizley, Alta; Mago, Pedro J.; Tobermann, James; Warren, Harrison R.

2015-01-01

Highlights: • Use of waste heat from a power generation unit to generate electricity is explored. • An organic Rankine cycle is used to recover the waste heat. • The system may lower cost, primary energy consumption, and carbon dioxide emission. • A parameter was established to show when the proposed system would provide savings. • The proposed system was evaluated in different locations in the US. - Abstract: This paper analyzes the potential of using the waste heat from a power generation unit to generate additional electricity using an organic Rankine cycle to reduce operational cost, primary energy consumption, and carbon dioxide emissions in different locations in the U.S. The power generation unit–organic Rankine cycle system is compared with a conventional system in terms of operational cost, primary energy consumption, and carbon dioxide emissions reduction. A parameter (R_m_i_n), which is based on system efficiencies, is established to determine when the proposed power generation unit–organic Rankine cycle system would potentially provide savings versus the conventional system in which electricity is purchased from the utility grid. The effect on the R_m_i_n parameter with variation of each system efficiency is also analyzed in this paper. Results indicated that savings in one parameter, such as primary energy consumption, did not imply savings in the other two parameters. Savings in the three parameters (operational cost, primary energy consumption, and carbon dioxide emissions) varied widely based on location due to prices of natural gas and electricity, source-to-site conversion factors, and carbon dioxide emissions conversion factors for electricity and natural gas. Variations in each system efficiency affected R_m_i_n, but varying the power generation unit efficiency had the most dramatic effect in the overall savings potential from the proposed system.

Power oscillation suppression by robust SMES in power system with large wind power penetration

International Nuclear Information System (INIS)

Ngamroo, Issarachai; Cuk Supriyadi, A.N.; Dechanupaprittha, Sanchai; Mitani, Yasunori

2009-01-01

The large penetration of wind farm into interconnected power systems may cause the severe problem of tie-line power oscillations. To suppress power oscillations, the superconducting magnetic energy storage (SMES) which is able to control active and reactive powers simultaneously, can be applied. On the other hand, several generating and loading conditions, variation of system parameters, etc., cause uncertainties in the system. The SMES controller designed without considering system uncertainties may fail to suppress power oscillations. To enhance the robustness of SMES controller against system uncertainties, this paper proposes a robust control design of SMES by taking system uncertainties into account. The inverse additive perturbation is applied to represent the unstructured system uncertainties and included in power system modeling. The configuration of active and reactive power controllers is the first-order lead-lag compensator with single input feedback. To tune the controller parameters, the optimization problem is formulated based on the enhancement of robust stability margin. The particle swarm optimization is used to solve the problem and achieve the controller parameters. Simulation studies in the six-area interconnected power system with wind farms confirm the robustness of the proposed SMES under various operating conditions

Power oscillation suppression by robust SMES in power system with large wind power penetration

Science.gov (United States)

Ngamroo, Issarachai; Cuk Supriyadi, A. N.; Dechanupaprittha, Sanchai; Mitani, Yasunori

2009-01-01

The large penetration of wind farm into interconnected power systems may cause the severe problem of tie-line power oscillations. To suppress power oscillations, the superconducting magnetic energy storage (SMES) which is able to control active and reactive powers simultaneously, can be applied. On the other hand, several generating and loading conditions, variation of system parameters, etc., cause uncertainties in the system. The SMES controller designed without considering system uncertainties may fail to suppress power oscillations. To enhance the robustness of SMES controller against system uncertainties, this paper proposes a robust control design of SMES by taking system uncertainties into account. The inverse additive perturbation is applied to represent the unstructured system uncertainties and included in power system modeling. The configuration of active and reactive power controllers is the first-order lead-lag compensator with single input feedback. To tune the controller parameters, the optimization problem is formulated based on the enhancement of robust stability margin. The particle swarm optimization is used to solve the problem and achieve the controller parameters. Simulation studies in the six-area interconnected power system with wind farms confirm the robustness of the proposed SMES under various operating conditions.

Calculation and Simulation Study on Transient Stability of Power System Based on Matlab/Simulink

Directory of Open Access Journals (Sweden)

Shi Xiu Feng

2016-01-01

Full Text Available The stability of the power system is destroyed, will cause a large number of users power outage, even cause the collapse of the whole system, extremely serious consequences. Based on the analysis in single machine infinite system as an example, when at the f point two phase ground fault occurs, the fault lines on either side of the circuit breaker tripping resection at the same time,respectively by two kinds of calculation and simulation methods of system transient stability analysis, the conclusion are consistent. and the simulation analysis is superior to calculation analysis.

The Application of Stationary VOC-PR with PLL for Grid side Converter-based Wind Power Generation System

DEFF Research Database (Denmark)

Guo, Yougui; Zeng, Ping; Li, Lijuan

2010-01-01

Voltage oriented control PR is combined with space vector modulation and phase locked loop to control the grid side converter in wind power generation system in this paper. First the mathematical models of grid side converter and LCL filter as well as grid are given. Then the control strategy...... of grid side converter-based wind power generation system is given in detail. Finally the simulation model consisting of the grid side converter wind power generation system is set up. The simulation results have verified that the control strategy is feasible to be used for control of gird currents......, active power, reactive power and DC-link voltage in wind power generation system. It has laid a good basis for the real system development....

Real-Time Tariffs for Electric Vehicles in Wind Power based Power Systems

DEFF Research Database (Denmark)

Morais, Hugo; Sousa, Tiago; Silva, Marco

2013-01-01

’ behaviour and also the impact in load diagram. The paper proposes the energy price variation according to the relation between wind generation and power consumption. The proposed strategy was tested in two different days in the Danish power system. January 31st and August 13th 2013 were selected because......The use of Electric Vehicles (EVs) will change significantly the planning and management of power systems in a near future. This paper proposes a real-time tariff strategy for the charge process of the EVs. The main objective is to evaluate the influence of real-time tariffs in the EVs owners...... of the high quantities of wind generation. The main goal is to evaluate the changes in the EVs charging diagram with the energy price preventing wind curtailment....

Guidelines for design and development of computer/microprocessor based systems in research and power reactors

International Nuclear Information System (INIS)

Dhodapkar, S.D.; Chandra, A.K.

1993-01-01

Computer systems are being used in Indian research reactors and nuclear power plants in the areas of data acquisition, process monitoring and control, alarm annunciation and safety. The design and evaluation of these systems requires a special approach particularly due to the unique nature of the software which is an essential constituent of these systems. It was decided to evolve guidelines for designing and review of computer/microprocessor based systems for use in nuclear power plants in India. The present document tries to address various issues and presents guidelines which are as comprehensive as possible and cover all issues relating to the design and development of computer based systems. These guidelines are expected to be useful to the specifiers, designers and reviewers of such systems. (author). 6 refs., 1 fig

WAMS Based Intelligent Operation and Control of Modern Power System with large Scale Renewable Energy Penetration

DEFF Research Database (Denmark)

Rather, Zakir Hussain

security limits. Under such scenario, progressive displacement of conventional generation by wind generation is expected to eventually lead a complex power system with least presence of central power plants. Consequently the support from conventional power plants is expected to reach its all-time low...... system voltage control responsibility from conventional power plants to wind turbines. With increased wind penetration and displaced conventional central power plants, dynamic voltage security has been identified as one of the challenging issue for large scale wind integration. To address the dynamic...... security issue, a WAMS based systematic voltage control scheme for large scale wind integrated power system has been proposed. Along with the optimal reactive power compensation, the proposed scheme considers voltage support from wind farms (equipped with voltage support functionality) and refurbished...

A portable solar-powered air-cooling system based on phase-change materials for a vehicle cabin

International Nuclear Information System (INIS)

Qi, Lingfei; Pan, Hongye; Zhu, Xin; Zhang, Xingtian; Salman, Waleed; Zhang, Zutao; Li, Li; Zhu, Miankuan; Yuan, Yanping; Xiang, Bo

2017-01-01

Graphical abstract: This paper proposed a portable solar-powered air cooling system for a vehicle cabin based on Phase-change Materials. The cooling system contains three main parts: a solar-energy collection module, an energy-storage module and a phase-change cooling module. The operating principle can be described as follows. For energy input, the solar-energy-collection module harvests solar energy and converts it to electricity. The power-storage module stores the electrical energy in the supercapacitor to power the electrical equipment, mainly the air pump (AP) and water pump (WP) of the phase-change cooling module. Finally, the phase-change cooling module provides cold air for the vehicle cabin to create a comfortable vehicle interior in a hot summer. The proposed system is demonstrated through thermal simulations, which show the long-duration cooling effect of the system. Temperature drops of were obtained in field tests, predicting that the proposed cooling system is beneficial and practical for cooling vehicle cabins. - Highlights: • A novel portable air cooling system based on PCMs is presented. • Solar energy was adopted to power the proposed air cooling system. • This proposed system is used for cooling vehicle cabins exposed to the sun. • Experimental results show that the proposed system has a good cooling effect. - Abstract: In summer, the temperature is very high inside vehicles parked under the hot sun. This causes consuming more fossil energy to power the air conditioner and generation of harmful gases. There is currently no effective method to address this problem in an energy-saving and environmentally friendly manner. In this paper, a novel solar-powered air-cooling system for vehicle cabins is proposed based on Phase-change Materials (PCMs); the system prevents the temperature inside a vehicle cabin from rising too high when the vehicle is parked outdoor exposure to the sun. The proposed system consists of three main parts: a solar

Control of Full-Scale Converter based Wind Power Plants for damping of low frequency system oscillations

DEFF Research Database (Denmark)

Adamczyk, Andrzej Grzegorz; Teodorescu, Remus; Rodriguez, Pedro

2011-01-01

Damping of low frequency power oscillations is one of essential aspects of maintaining power system stability. In literature can be found publications on damping capability of Doubly Fed Induction Generator based wind turbines. This paper extends discussion on Wind Power Plant damping capability...

Implementation and Optimization of GPU-Based Static State Security Analysis in Power Systems

Directory of Open Access Journals (Sweden)

Yong Chen

2017-01-01

Full Text Available Static state security analysis (SSSA is one of the most important computations to check whether a power system is in normal and secure operating state. It is a challenge to satisfy real-time requirements with CPU-based concurrent methods due to the intensive computations. A sensitivity analysis-based method with Graphics processing unit (GPU is proposed for power systems, which can reduce calculation time by 40% compared to the execution on a 4-core CPU. The proposed method involves load flow analysis and sensitivity analysis. In load flow analysis, a multifrontal method for sparse LU factorization is explored on GPU through dynamic frontal task scheduling between CPU and GPU. The varying matrix operations during sensitivity analysis on GPU are highly optimized in this study. The results of performance evaluations show that the proposed GPU-based SSSA with optimized matrix operations can achieve a significant reduction in computation time.

Power law-based local search in spider monkey optimisation for lower order system modelling

Science.gov (United States)

Sharma, Ajay; Sharma, Harish; Bhargava, Annapurna; Sharma, Nirmala

2017-01-01

The nature-inspired algorithms (NIAs) have shown efficiency to solve many complex real-world optimisation problems. The efficiency of NIAs is measured by their ability to find adequate results within a reasonable amount of time, rather than an ability to guarantee the optimal solution. This paper presents a solution for lower order system modelling using spider monkey optimisation (SMO) algorithm to obtain a better approximation for lower order systems and reflects almost original higher order system's characteristics. Further, a local search strategy, namely, power law-based local search is incorporated with SMO. The proposed strategy is named as power law-based local search in SMO (PLSMO). The efficiency, accuracy and reliability of the proposed algorithm is tested over 20 well-known benchmark functions. Then, the PLSMO algorithm is applied to solve the lower order system modelling problem.

Selectivity of power system protections at power swings in power system

Directory of Open Access Journals (Sweden)

Jan Machowski

2012-12-01

Full Text Available The paper discusses out-of-step protection systems such as: generator pole slip protections, out of step tripping protections, distance protections of step-up transformer, distance protections of transmission lines and transformers, power swing blocking, and special out-of-step protection. It is shown that all these protections make up a protection system, to which a setting concept uniform for the entire power system has to be applied. If a power system is inappropriately equipped with these protections, or their settings are inappropriate, they may operate unselectively, thus contributing to the development of power system blackouts. In the paper the concepts for a real power system are given for the two stages: target stage fully compliant with selectivity criteria, and transitional stage between the current and target stages.

Semidefinite Relaxation-Based Optimization of Multiple-Input Wireless Power Transfer Systems

Science.gov (United States)

Lang, Hans-Dieter; Sarris, Costas D.

2017-11-01

An optimization procedure for multi-transmitter (MISO) wireless power transfer (WPT) systems based on tight semidefinite relaxation (SDR) is presented. This method ensures physical realizability of MISO WPT systems designed via convex optimization -- a robust, semi-analytical and intuitive route to optimizing such systems. To that end, the nonconvex constraints requiring that power is fed into rather than drawn from the system via all transmitter ports are incorporated in a convex semidefinite relaxation, which is efficiently and reliably solvable by dedicated algorithms. A test of the solution then confirms that this modified problem is equivalent (tight relaxation) to the original (nonconvex) one and that the true global optimum has been found. This is a clear advantage over global optimization methods (e.g. genetic algorithms), where convergence to the true global optimum cannot be ensured or tested. Discussions of numerical results yielded by both the closed-form expressions and the refined technique illustrate the importance and practicability of the new method. It, is shown that this technique offers a rigorous optimization framework for a broad range of current and emerging WPT applications.

Integrating wind power in the (French) power system

International Nuclear Information System (INIS)

Pellen, A.

2007-03-01

RTE and EDF have no other technological option than to restrain the contribution of the French wind power fleet to base-load generation where it comes in direct competition with the nuclear power plants. The author aims to explain this situation and answer the following questions. Why the fossil fueled reactor fleet in France will not be affected by an evolution of the wind power capacity? Why, in France electric power generation-demand SYSTEM wind power cannot be a substitute for fossil fueled thermal units? (A.L.B.)

Knowledge based support for real time application of multiagent control and automation in electric power systems

DEFF Research Database (Denmark)

Saleem, Arshad; Nordstrom, Lars; Lind, Morten

2011-01-01

This paper presents a mechanism for developing knowledge based support for real time application of multiagent systems (MAS) in control, automation and diagnosis of electric power systems. In particular it presents a way for autonomous agents to utilize a qualitative means-ends based model...... for reasoning about control situations. The proposed mechanism has been used in different scenarios of electric power distribution system protection and control. Results show that agents can use local models of their environment and coordinate with other agents to analyze and understand a disturbance situation...

Evaluating a k-nearest neighbours-based classifier for locating faulty areas in power systems

Directory of Open Access Journals (Sweden)

Juan José Mora Flórez

2008-09-01

Full Text Available This paper reports a strategy for identifying and locating faults in a power distribution system. The strategy was based on the K-nearest neighbours technique. This technique simply helps to estimate a distance from the features used for describing a particu-lar fault being classified to the faults presented during the training stage. If new data is presented to the proposed fault locator, it is classified according to the nearest example recovered. A characterisation of the voltage and current measurements obtained at one single line end is also presented in this document for assigning the area in the case of a fault in a power system. The pro-posed strategy was tested in a real power distribution system, average 93% confidence indexes being obtained which gives a good indicator of the proposal’s high performance. The results showed how a fault could be located by using features obtained from voltage and current, improving utility response and thereby improving system continuity indexes in power distribution sys-tems.

A minimal order observer based frequency control strategy for an integrated wind-battery-diesel power system

International Nuclear Information System (INIS)

Howlader, Abdul Motin; Izumi, Yuya; Uehara, Akie; Urasaki, Naomitsu; Senjyu, Tomonobu; Yona, Atsushi; Saber, Ahmed Yousuf

2012-01-01

Wind energy is a fluctuating resource which can diverge quickly and causes the frequency deviation. To overcome this problem, the current paper deals with a frequency control scheme for a small power system by a coordinated control strategy of a wind turbine generator (WTG) and a battery energy storage system (BESS). The small power system composes of a wind turbine, a battery storage and a diesel generator. A minimal order observer is utilized as a disturbance observer to estimate the load of the power system. The load deviations are considered in a frequency domain. The low frequency component is reduced by the pitch angle control system of the WTG, while the high frequency component is reduced by the charge/discharge of the BESS, respectively. The output power command of the BESS is determined according to the state of charge, the high frequency component of the frequency deviation and the load variation. The proposed method is compared with the conventional method in different cases. By using the proposed method, the capacity of the battery is decreased by the charge/discharge of the BESS in long term. To enhance the control performance, the generalized predictive control (GPC) method is introduced to the pitch angle control system of the WTG. Effectiveness of the proposed method is verified by the numerical simulations. -- Highlights: ► A coordinated control method for a WTG and a BESS in the small power system. ► To achieve this objective, a minimal order observer is utilized. ► The output power command of the WTG is based on the wind speed and the estimated frequency deviations. ► The output power the WTG is controlled by the GPC based robust pitch angle control system. ► The output power command of the BESS is determined by the state of charge and the estimated frequency deviations.

Supervision functions - Secure operation of sustainable power systems

DEFF Research Database (Denmark)

Morais, Hugo; Zhang, Xinxin; Lind, Morten

2013-01-01

of power systems operation control. The use of PMUs allows more penetration of DG mainly, with technologies based on renewable resources with intermittent and unpredictable operation such a wind power. This paper introduces the Secure Operation of Sustainable Power Systems (SOSPO) project. The SOSPO...... project tries to respond to the question "How to ensure a secure operation of the future power system where the operating point is heavily is fluctuating?" focusing in the Supervision module architecture and in the power system operation states. The main goal of Supervision module is to determine...... the power system operation state based on new stability and security parameters derived from PMUs measurement and coordinate the use of automatic and manual control actions. The coordination of the control action is based not only in the static indicators but also in the performance evaluation of control...

An overview of a knowledge based system for preventive maintenance support of nuclear power plants

International Nuclear Information System (INIS)

Terano, Takao; Nishiyama, Takuya; Yokoo, Takeshi

1984-01-01

In recent years, much interest has been paid to knowledge engineering techniques for new vehicles of advanced information processing. As a practical application in electric power industry, this report discusses a knowledge based system for supporting preventive maintenance of nuclear power plants. To support preventive maintenance tasks, the system must have facilities to reason failures and accidents of the plants, to evaluate their significance, to predict any possible troubles, and to indentify appropriate preventive countermeasures for them. This report describes the overview of the prototype system from a viewpoint of knowledge engineering. The results of the study are as follows: (1) The knowledge base of the prototype system consists of a data-base on plants and a rule-base derived from experts' knowledge. Using the information in the knowledge base, the system diagnoses the plant without real-time interaction with operational plants. (2) Expert's knowledge in the rule-base is represented in the non-procedural declarative forms. These rules are organized in some hierarchical structure so as to be used efficiently and used in conjunction with the corresponding set of plant information in the data-base. (3) The prototype system is incrementally developed with the rapid prototyping techniques, that is, the processes of design, implementation and evaluation are repeated several times. (author)

Research on integrated managing system based on CIMS for nuclear power plant safety

International Nuclear Information System (INIS)

Zhou Gang

2006-01-01

In order to improve safety, economy and reliability of operation for nuclear power plant (NPP), a novel integrated managing method was proposed based on the ideas of computer and contemporary integrated manufacturing system (CIMS). The application of CIMS to nuclear power plant safety management was researched. In order to design an integrated managing system to meet the needs of NPP safety management, all work related to nuclear safety is divided into different category according to its characters. On basis of this work, general integrated managing system was designed at first. Then subsystems were designed and every subsystem implements a category of nuclear safety management work. All subsystems are independent relatively on the one hand and are interrelated on other hand by global information system. (authors)

Exergy analysis of a coal/biomass co-hydrogasification based chemical looping power generation system

International Nuclear Information System (INIS)

Yan, Linbo; Yue, Guangxi; He, Boshu

2015-01-01

Power generation from co-utilization of coal and biomass is very attractive since this technology can not only save the coal resource but make sufficient utilization of biomass. In addition, with this concept, net carbon discharge per unit electric power generation can also be sharply reduced. In this work, a coal/biomass co-hydrogasification based chemical looping power generation system is presented and analyzed with the assistance of Aspen Plus. The effects of different operating conditions including the biomass mass fraction, R_b, the hydrogen recycle ratio, R_h_r, the hydrogasification pressure, P_h_g, the iron to fuel mole ratio, R_i_f, the reducer temperature, T_r_e, the oxidizer temperature, T_o_x, and the fuel utilization factor, U_f of the SOFC (solid oxide fuel cell) on the system operation results including the energy efficiency, η_e, the total energy efficiency, η_t_e, the exergy efficiency, η_e_x, the total exergy efficiency, η_t_e_x and the carbon capture rate, η_c_c, are analyzed. The energy and exergy balances of the whole system are also calculated and the corresponding Sankey diagram and Grassmann diagram are drawn. Under the benchmark condition, exergy efficiencies of different units in the system are calculated. η_t_e, η_t_e_x and η_c_c of the system are also found to be 43.6%, 41.2% and 99.1%, respectively. - Highlights: • A coal/biomass co-hydrogasification based chemical looping power generation system is setup. • Sankey and Grassmann diagrams are presented based on the energy and exergy balance calculations. • Sensitivity analysis is done to understand the system operation characteristics. • Total energy and exergy efficiencies of this system can be 43.6% and 41.2%, respectively. • About 99.1% of the carbon contained in coal and biomass can be captured in this system.

Mitigation of Power System Oscillation Caused by Wind Power Fluctuation

DEFF Research Database (Denmark)

Su, Chi; Hu, Weihao; Chen, Zhe

2013-01-01

oscillation mitigation controllers are proposed and compared. A model of direct-drive-full-convertor-based wind farm connected to the IEEE 10-machine 39-bus system is adopted as the test system. The calculations and simulations are conducted in DIgSILENT PowerFactory 14.0. Results are presented to show......Wind power is increasingly integrated in modern power grids, which brings new challenges to the power system operation. Wind power is fluctuating because of the uncertain nature of wind, whereas wind shear and tower shadow effects also cause periodic fluctuations. These may lead to serious forced...... oscillation when the frequencies of the periodic fluctuations are close to the natural oscillation frequencies of the connected power system. By using modal analysis and time-domain simulations, this study studies the forced oscillation caused by the wind shear and tower shadow effects. Three forced...

A Multiagent System for Autonomous Operation of Islanded Microgrids Based on a Power Market Environment

Directory of Open Access Journals (Sweden)

Myong-Chul Shin

2010-12-01

Full Text Available One of the most important requirements of microgrid operation is to maintain a constant frequency such as 50 Hz or 60 Hz, which is closely related to a power balance between supply and demand. In general, microgrids are connected to power grids and surplus/shortage power of microgrids is traded with power grids. Since islanded microgrids are isolated from any power grids, the decrease in generation or load-shedding can be used to maintain the frequency when a power imbalance between supply and demand occurs. The power imbalance restricts the electricity use of consumers in the case of supply shortage and the power supply of suppliers in the case of supply surplus. Therefore, the islanded microgrid should be operated to reduce power imbalance conditions. Meanwhile, the microgrid is a small-scale power system and the employment of skillful operators for effective operation of its components requires high costs. Therefore, automatic operation of the components is effective realistically. In addition, the components are distributed in the microgrid and their operation should consider their owners’ profits. For these reasons, a multiagent system application can be a good alternative for microgrid operation. In this paper, we present a multiagent system for autonomous operation of the islanded microgrid on a power market environment. The proposed multiagent system is designed based on a cooperative operation scheme. We show the functionality and the feasibility of the proposed multiagent system through several tests.

A multiagent system for autonomous operation of islanded microgrids based on a power market environment

Energy Technology Data Exchange (ETDEWEB)

Kim, H.-M. [Department of Electrical Engineering, University of Incheon/12-1, Sondo-dong, Yeonsu-gu, Incheon, 406-840 (Korea, Republic of); Kinoshita, T. [Graduate School of Information Science, Tohoku University/2-1-1, Katahira, Aoba-ku, Sendai, 980-8577 (Japan); Shin, M.-Ch. [School of Information and Communication Engineering, Sungkyunkwan University/300, Cheoncheon-dong, Jangan-gu, Suwon, Gyeonggi-do, 440-746 (Korea, Republic of)

2010-12-15

One of the most important requirements of microgrid operation is to maintain a constant frequency such as 50 Hz or 60 Hz, which is closely related to a power balance between supply and demand. In general, microgrids are connected to power grids and surplus/shortage power of microgrids is traded with power grids. Since islanded microgrids are isolated from any power grids, the decrease in generation or load-shedding can be used to maintain the frequency when a power imbalance between supply and demand occurs. The power imbalance restricts the electricity use of consumers in the case of supply shortage and the power supply of suppliers in the case of supply surplus. Therefore, the islanded microgrid should be operated to reduce power imbalance conditions. Meanwhile, the microgrid is a small-scale power system and the employment of skillful operators for effective operation of its components requires high costs. Therefore, automatic operation of the components is effective realistically. In addition, the components are distributed in the microgrid and their operation should consider their owners' profits. For these reasons, a multiagent system application can be a good alternative for microgrid operation. In this paper, we present a multiagent system for autonomous operation of the islanded microgrid on a power market environment. The proposed multiagent system is designed based on a cooperative operation scheme. We show the functionality and the feasibility of the proposed multiagent system through several tests. (authors)

Modeling Power Systems as Complex Adaptive Systems

Energy Technology Data Exchange (ETDEWEB)

Chassin, David P.; Malard, Joel M.; Posse, Christian; Gangopadhyaya, Asim; Lu, Ning; Katipamula, Srinivas; Mallow, J V.

2004-12-30

Physical analogs have shown considerable promise for understanding the behavior of complex adaptive systems, including macroeconomics, biological systems, social networks, and electric power markets. Many of today's most challenging technical and policy questions can be reduced to a distributed economic control problem. Indeed, economically based control of large-scale systems is founded on the conjecture that the price-based regulation (e.g., auctions, markets) results in an optimal allocation of resources and emergent optimal system control. This report explores the state-of-the-art physical analogs for understanding the behavior of some econophysical systems and deriving stable and robust control strategies for using them. We review and discuss applications of some analytic methods based on a thermodynamic metaphor, according to which the interplay between system entropy and conservation laws gives rise to intuitive and governing global properties of complex systems that cannot be otherwise understood. We apply these methods to the question of how power markets can be expected to behave under a variety of conditions.

Automatic supervision and fault detection of PV systems based on power losses analysis

Energy Technology Data Exchange (ETDEWEB)

Chouder, A.; Silvestre, S. [Electronic Engineering Department, Universitat Politecnica de Catalunya, C/Jordi Girona 1-3, Campus Nord UPC, 08034 Barcelona (Spain)

2010-10-15

In this work, we present a new automatic supervision and fault detection procedure for PV systems, based on the power losses analysis. This automatic supervision system has been developed in Matlab and Simulink environment. It includes parameter extraction techniques to calculate main PV system parameters from monitoring data in real conditions of work, taking into account the environmental irradiance and module temperature evolution, allowing simulation of the PV system behaviour in real time. The automatic supervision method analyses the output power losses, presents in the DC side of the PV generator, capture losses. Two new power losses indicators are defined: thermal capture losses (L{sub ct}) and miscellaneous capture losses (L{sub cm}). The processing of these indicators allows the supervision system to generate a faulty signal as indicator of fault detection in the PV system operation. Two new indicators of the deviation of the DC variables respect to the simulated ones have been also defined. These indicators are the current and voltage ratios: R{sub C} and R{sub V}. Analysing both, the faulty signal and the current/voltage ratios, the type of fault can be identified. The automatic supervision system has been successfully tested experimentally. (author)

Automatic supervision and fault detection of PV systems based on power losses analysis

International Nuclear Information System (INIS)

Chouder, A.; Silvestre, S.

2010-01-01

In this work, we present a new automatic supervision and fault detection procedure for PV systems, based on the power losses analysis. This automatic supervision system has been developed in Matlab and Simulink environment. It includes parameter extraction techniques to calculate main PV system parameters from monitoring data in real conditions of work, taking into account the environmental irradiance and module temperature evolution, allowing simulation of the PV system behaviour in real time. The automatic supervision method analyses the output power losses, presents in the DC side of the PV generator, capture losses. Two new power losses indicators are defined: thermal capture losses (L ct ) and miscellaneous capture losses (L cm ). The processing of these indicators allows the supervision system to generate a faulty signal as indicator of fault detection in the PV system operation. Two new indicators of the deviation of the DC variables respect to the simulated ones have been also defined. These indicators are the current and voltage ratios: R C and R V . Analysing both, the faulty signal and the current/voltage ratios, the type of fault can be identified. The automatic supervision system has been successfully tested experimentally.

A new VME-based high voltage power supply for large photomultiplier systems

International Nuclear Information System (INIS)

Neumaier, S.; Hubbeling, T.; Kolb, B.W.; Purschke, M.L.; Ippolitov, M.; Blume, C.; Bohne, E.M.; Bucher, D.; Claussen, A.; Peitzmann, T.; Schepers, G.; Schlagheck, H.

1995-01-01

We describe a new high voltage power supply, developed for the leadglass calorimeter of the WA98 experiment at CERN. The high voltage is produced for each of the 10,080 photomultiplier tubes of the detector individually, by the same number of active bases with on-board Greinacher voltage multipliers. The full VME-based HV controller system, which addresses each base via bus cables once per second, is miniaturized and fits into a single VME crate. The main advantages of this approach are the low heat dissipation, the considerably reduced amount of cabling and cost, as well as the high stability and low noise of the system. (orig.)

RIMAP demonstration project. Risk-based life management of piping system in power plant Heilbronn

International Nuclear Information System (INIS)

Bareiss, J.; Buck, P.; Matschecko, B.; Jovanovic, A.; Balos, D.; Perunicic, M.

2004-01-01

In the framework of EU project RIMAP [Risk Based Inspection and Maintenance Procedures for European Industry (2000)] a new European Guideline for optimized risk based maintenance and inspection planning of industrial plants (RBLM, Risk Based Life Management) is being developed. The RIMAP project consists of the three clustered projects: - development (RTD); - demonstration (DEMO): - thematic network (TN). Current work and future, planned work in RIMAP demonstration project on applications of the RIMAP methodology in power plants are presented briefly in the first part of the paper. Also presented in the paper are the results of a preliminary analysis of piping system in power plant Heilbronn using the concept of risk-based monitoring as part of overall concept of risk-based life management. Shortly the following issues are discussed in the paper: - identification of critical components; - application of a multilevel risk analysis (...from 'screening' to 'detailed analysis'); - determination of PoF (Probability of Failure); - determination of CoF (Consequence of Failure); - optimation of inspection and maintenance plan. From our experience with the application of the RIMAP methodology the following conclusions can be drawn: The use of risk-based methods in inspection and maintenance of piping systems in power plants gives transparency to the decision making process and gives an optimized maintenance policy based on current state of the components. The results of the work clearly show the power of the proposed method for concentration on critical items: out of 64 monitored components 5 were selected for intermediate analysis and only 1 for the detailed analysis (probabilistic high temperature fracture mechanics)

A coherency-based method to increase dynamic security in power systems

Energy Technology Data Exchange (ETDEWEB)

De Tuglie, E. [Dipartimento di Ingegneria dell' Ambiente e per lo Sviluppo Sostenibile - DIASS, Politecnico di Bari, Viale del Turismo 8, 74100 Taranto (Italy); Iannone, S.M.; Torelli, F. [Dipartimento di Elettrotecnica ed Elettronica - DEE, Politecnico di Bari, Via Re David 200, 70125 Bari (Italy)

2008-08-15

Dynamic security analysis is the evaluation of the ability of a system to withstand contingencies by surviving transient conditions to acceptable steady-state operative states. When potential instability due to contingency is detected, preventive action may be desired to improve the system security. This is very important in the on-line operation of a power system, especially when the system is stability-limited. The method proposed in this paper is based on the idea that increasing coherency between generators in the transient behaviour following a system perturbation gives rise to a more stable system. In this paper, we suggest the use of the ''input-output feedback-linearization'' with a reference trajectory obtained using a system dynamic equivalent based on the centre of inertia. To quantify coherency levels a new coherency indicator has been assumed for the given reference trajectory. The result is an increasing level in coherency, critical clearing time and system stability. The method is tested on the IEEE 30 bus test system. (author)

Optimization-based power management of hybrid power systems with applications in advanced hybrid electric vehicles and wind farms with battery storage

Science.gov (United States)

Borhan, Hoseinali

Modern hybrid electric vehicles and many stationary renewable power generation systems combine multiple power generating and energy storage devices to achieve an overall system-level efficiency and flexibility which is higher than their individual components. The power or energy management control, "brain" of these "hybrid" systems, determines adaptively and based on the power demand the power split between multiple subsystems and plays a critical role in overall system-level efficiency. This dissertation proposes that a receding horizon optimal control (aka Model Predictive Control) approach can be a natural and systematic framework for formulating this type of power management controls. More importantly the dissertation develops new results based on the classical theory of optimal control that allow solving the resulting optimal control problem in real-time, in spite of the complexities that arise due to several system nonlinearities and constraints. The dissertation focus is on two classes of hybrid systems: hybrid electric vehicles in the first part and wind farms with battery storage in the second part. The first part of the dissertation proposes and fully develops a real-time optimization-based power management strategy for hybrid electric vehicles. Current industry practice uses rule-based control techniques with "else-then-if" logic and look-up maps and tables in the power management of production hybrid vehicles. These algorithms are not guaranteed to result in the best possible fuel economy and there exists a gap between their performance and a minimum possible fuel economy benchmark. Furthermore, considerable time and effort are spent calibrating the control system in the vehicle development phase, and there is little flexibility in real-time handling of constraints and re-optimization of the system operation in the event of changing operating conditions and varying parameters. In addition, a proliferation of different powertrain configurations may

Hybrid Genetic Algorithm Fuzzy-Based Control Schemes for Small Power System with High-Penetration Wind Farms

Directory of Open Access Journals (Sweden)

Mohammed Elsayed Lotfy

2018-03-01

Full Text Available Wind is a clean, abundant, and inexhaustible source of energy. However, wind power is not constant, as windmill output is proportional to the cube of wind speed. As a result, the generated power of wind turbine generators (WTGs fluctuates significantly. Power fluctuation leads to frequency deviation and voltage flicker inside the system. This paper presents a new methodology for controlling system frequency and power. Two decentralized fuzzy logic-based control schemes with a high-penetration non-storage wind–diesel system are studied. First, one is implemented in the governor of conventional generators to damp frequency oscillation, while the other is applied to control the pitch angle system of wind turbines to smooth wind output power fluctuations and enhance the power system performance. A genetic algorithm (GA is employed to tune and optimize the membership function parameters of the fuzzy logic controllers to obtain optimal performance. The effectiveness of the suggested controllers is validated by time domain simulation for the standard IEEE nine-bus three-generator test system, including three wind farms. The robustness of the power system is checked under normal and faulty operating conditions.

HPS: A space fission power system suitable for near-term, low-cost lunar and planetary bases

International Nuclear Information System (INIS)

Houts, M.G.; Poston, D.I.; Ranken, W.A.

1996-01-01

Near-term, low-cost space fission power systems can enhance the feasibility and utility of lunar and planetary bases. One such system, the Heatpipe Power System (HPS), is described in this paper. The HPS draws on 40 yr of United States and international experience to enable a system that can be developed in <5 yr at a cost of <$100M. Total HPS mass is <600 kg at 5 kWe and <2000 kg at 50 kWe, assuming that thermoelectric power conversion is used. More advanced power conversion systems could reduce system mass significantly. System mass for planetary surface systems also may be reduced (1) if indigenous material is used for radiation shielding and (2) because of the positive effect of the gravitational field on heatpipe operation. The HPS is virtually non-radioactive at launch and is passively subcritical during all credible launch accidents. Full-system electrically heated testing is possible, and a ground nuclear power test is not needed for flight qualification. Fuel burnup limits are not reached for several decades, thus giving the system long-life potential

Fuzzy wavelet plus a quantum neural network as a design base for power system stability enhancement.

Science.gov (United States)

Ganjefar, Soheil; Tofighi, Morteza; Karami, Hamidreza

2015-11-01

In this study, we introduce an indirect adaptive fuzzy wavelet neural controller (IAFWNC) as a power system stabilizer to damp inter-area modes of oscillations in a multi-machine power system. Quantum computing is an efficient method for improving the computational efficiency of neural networks, so we developed an identifier based on a quantum neural network (QNN) to train the IAFWNC in the proposed scheme. All of the controller parameters are tuned online based on the Lyapunov stability theory to guarantee the closed-loop stability. A two-machine, two-area power system equipped with a static synchronous series compensator as a series flexible ac transmission system was used to demonstrate the effectiveness of the proposed controller. The simulation and experimental results demonstrated that the proposed IAFWNC scheme can achieve favorable control performance. Copyright © 2015 Elsevier Ltd. All rights reserved.

Power reactor information system (PRIS)

International Nuclear Information System (INIS)

1989-06-01

Since the very beginning of commercial operation of nuclear power plants, the nuclear power industry worldwide has accumulated more than 5000 reactor years of experience. The IAEA has been collecting Operating Experience data for Nuclear Power Plants since 1970 which were computerized in 1980. The Agency has undertaken to make Power Reactor Information System (PRIS) available on-line to its Member States. The aim of this publication is to provide the users of PRIS from their terminals with description of data base and communication systems and to show the methods of accessing the data

Investigating power control in autonomous power systems with increasing wind power penetration

Energy Technology Data Exchange (ETDEWEB)

Margaris, Ioannis D. [National Technical Univ. of Athens (Greece). Electric Energy Systems Lab.; Hansen, Anca D.; Sorensen, Poul [Risoe National Laboratory, Roskilde (Denmark). Wind Energy Dept.; Hatziargyriou, Nikos D. [National Technical Univ. of Athens (Greece). Electric Energy Systems Lab.; Public Power Corporation S.A., Athens (Greece)

2009-07-01

Increasing levels of wind penetration in autonomous power systems has set intensively high standards with respect to wind turbine technology during the last years. Special features of non-interconnected power systems make security issues rather critical, as the operation of large wind farms like conventional power plants is becoming a necessity. This paper includes the study case of Rhodos island, in Greece, where rapidly increasing wind penetration has started to impose serious security issues for the immediate future. The scenarios studied here correspond to reference year of study 2012 and include wind farms with three different wind turbine technologies - namely Doubly Fed Induction Generator (DFIG), Permanent Magnet Synchronous Generator (PMSG) and Active Stall Induction Generator (ASIG) based wind turbines. Aggregated models of the wind farms are being used and results for different load cases are being analyzed and discussed. The ability of wind farms to assist in some of the power system control services traditionally carried out by conventional synchronous generation is being investigated and discussed. The power grid of the island, including speed governors and automatic voltage regulators, is simulated in the dedicated power system simulation program Power Factory from DIgSILENT. (orig.)

A risk-based review of Instrument Air systems at nuclear power plants

International Nuclear Information System (INIS)

DeMoss, G.; Lofgren, E.; Rothleder, B.; Villeran, M.; Ruger, C.

1990-01-01

The broad objective of this analysis was to provide risk-based information to help focus regulatory actions related to Instrument Air (IA) systems at operating nuclear power plants. We first created an extensive data base of summarized and characterized IA-related events that gave a qualitative indication of the nature and severity of these events. Additionally, this data base was used to calculate the frequencies of certain events, which were used in the risk analysis. The risk analysis consisted of reviewing published PRAs and NRC Accident Sequence Precursor reports for IA-initiated accident sequences, IA interactions with frontline systems, and IA-related risk significant events. Sensitivity calculations were performed when possible. Generically, IA was found to contribute less to total risk than many safety systems; however, specific design weaknesses in safety systems, non-safety systems, and the IA system were found to be significant in risk. 22 refs., 13 figs., 24 tabs

A Novel Evaluation Model for Hybrid Power System Based on Vague Set and Dempster-Shafer Evidence Theory

Directory of Open Access Journals (Sweden)

Dongxiao Niu

2012-01-01

Full Text Available Because clean energy and traditional energy have different advantages and disadvantages, it is of great significance to evaluate comprehensive benefits for hybrid power systems. Based on thorough analysis of important characters on hybrid power systems, an index system including security, economic benefit, environmental benefit, and social benefit is established in this paper. Due to advantages of processing abundant uncertain and fuzzy information, vague set is used to determine the decision matrix. Convert vague decision matrix to real one by vague combination ruleand determine uncertain degrees of different indexes by grey incidence analysis, then the mass functions of different comment set in different indexes are obtained. Information can be fused in accordance with Dempster-Shafer (D-S combination rule and the evaluation result is got by vague set and D-S evidence theory. A simulation of hybrid power system including thermal power, wind power, and photovoltaic power in China is provided to demonstrate the effectiveness and potential of the proposed design scheme. It can be clearly seen that the uncertainties in decision making can be dramatically decreased compared with existing methods in the literature. The actual implementation results illustrate that the proposed index system and evaluation model based on vague set and D-S evidence theory are effective and practical to evaluate comprehensive benefit of hybrid power system.

Reliability analysis for power supply system in a reprocessing facility based on GO methodology

International Nuclear Information System (INIS)

Wang Renze

2014-01-01

GO methodology was applied to analyze the reliability of power supply system in a typical reprocessing facility. Based on the fact that tie breakers are set in the system, tie breaker operator was defined. Then GO methodology modeling and quantitative analysis were performed sequently, minimal cut sets and average unavailability of the system were obtained. Parallel analysis between GO methodology and fault tree methodology was also performed. The results showed that setup of tie breakers was rational and necessary and that the modeling was much easier and the chart was much more succinct for GO methodology parallel with fault tree methodology to analyze the reliability of the power supply system. (author)

Development of web-based integrity evaluation system for primary components in a nuclear power plant

Energy Technology Data Exchange (ETDEWEB)

Lee, S.M.; Kim, J.C.; Choi, J.B.; Kim, Y.J. [SAFE Research Center, Sungkyunkwan Univ., Suwon (Korea); Choi, S.N.; Jang, K.S.; Hong, S.Y. [Korea Electronic Power Research Inst., Daejeon (Korea)

2004-07-01

A nuclear power plant is composed of a number of primary components. Maintaining the integrity of these components is one of the most critical issues in nuclear industry. In order to maintain the integrity of these primary components, a complicated procedure is required including periodical in-service inspection, failure assessment, fracture mechanics analysis, etc. Also, experts in different fields have to co-operate to resolve the integrity issues on the basis of inspection results. This integrity evaluation process usually takes long, and thus, is detrimental for the plant productivity. Therefore, an effective safety evaluation system is essential to manage integrity issues on a nuclear power plant. In this paper, a web-based integrity evaluation system for primary components in a nuclear power plant is proposed. The proposed system, which is named as WEBIES (web-based integrity evaluation system), has been developed in the form of 3-tier system architecture. The system consists of three servers; application program server, user interface program server and data warehouse server. The application program server includes the defect acceptance analysis module and the fracture mechanics analysis module which are programmed on the basis of ASME sec. XI, appendix A. The data warehouse server provides data for the integrity evaluation including material properties, geometry information, inspection data and stress data. The user interface program server provides information to all co- workers in the field of integrity evaluation. The developed system provides engineering knowledge-based information and concurrent and collaborative working environment through internet, and thus, is expected to raise the efficiency of integrity evaluation procedures on primary components of a nuclear power plant. (orig.)

Development of web-based integrity evaluation system for primary components in a nuclear power plant

International Nuclear Information System (INIS)

Lee, S.M.; Kim, J.C.; Choi, J.B.; Kim, Y.J.; Choi, S.N.; Jang, K.S.; Hong, S.Y.

2004-01-01

A nuclear power plant is composed of a number of primary components. Maintaining the integrity of these components is one of the most critical issues in nuclear industry. In order to maintain the integrity of these primary components, a complicated procedure is required including periodical in-service inspection, failure assessment, fracture mechanics analysis, etc. Also, experts in different fields have to co-operate to resolve the integrity issues on the basis of inspection results. This integrity evaluation process usually takes long, and thus, is detrimental for the plant productivity. Therefore, an effective safety evaluation system is essential to manage integrity issues on a nuclear power plant. In this paper, a web-based integrity evaluation system for primary components in a nuclear power plant is proposed. The proposed system, which is named as WEBIES (web-based integrity evaluation system), has been developed in the form of 3-tier system architecture. The system consists of three servers; application program server, user interface program server and data warehouse server. The application program server includes the defect acceptance analysis module and the fracture mechanics analysis module which are programmed on the basis of ASME sec. XI, appendix A. The data warehouse server provides data for the integrity evaluation including material properties, geometry information, inspection data and stress data. The user interface program server provides information to all co- workers in the field of integrity evaluation. The developed system provides engineering knowledge-based information and concurrent and collaborative working environment through internet, and thus, is expected to raise the efficiency of integrity evaluation procedures on primary components of a nuclear power plant. (orig.)

Communication Systems and Study Method for Active Distribution Power systems

DEFF Research Database (Denmark)

Wei, Mu; Chen, Zhe

Due to the involvement and evolvement of communication technologies in contemporary power systems, the applications of modern communication technologies in distribution power system are becoming increasingly important. In this paper, the International Organization for Standardization (ISO......) reference seven-layer model of communication systems, and the main communication technologies and protocols on each corresponding layer are introduced. Some newly developed communication techniques, like Ethernet, are discussed with reference to the possible applications in distributed power system....... The suitability of the communication technology to the distribution power system with active renewable energy based generation units is discussed. Subsequently the typical possible communication systems are studied by simulation. In this paper, a novel method of integrating communication system impact into power...

Modelling a reliable wind/PV/storage power system for remote radio base station sites without utility power

Energy Technology Data Exchange (ETDEWEB)

Bitterlin, Ian F [Emerson Network Power Ltd., Globe Park, Marlow, SL7 1YG (United Kingdom)

2006-11-22

The development of photovoltaic (PV) cells has made steady progress from the early days, when only the USA space program could afford to deploy them, to now, seeing them applied to roadside applications even in our Northern European climes. The manufacturing cost per watt has fallen and the daylight-to-power conversion efficiency increased. At the same time, the perception that the sun has to be directly shining on it for a PV array to work has faded. On some of those roadside applications, particularly for remote emergency telephones or for temporary roadwork signage where a utility electrical power connection is not practical, the keen observer will spot, usually in addition to a PV array, a small wind-turbine and an electrical cabinet quite obviously (by virtue of its volume) containing a storage battery. In the UK, we have the lions share (>40%) of Europe's entire wind power resource although, despite press coverage of the 'anti-wind' lobby to the contrary, we have hardly started to harvest this clean and free energy source. Taking this (established and proven) roadside solution one step further, we will consider higher power applications. A cellular phone system is one where a multitude of remote radio base stations (RBS) are required to provide geographical coverage. With networks developing into the so called '3G' technologies the need for base stations has tripled, as each 3G cell covers only 1/3 the geographical area of its '2G' counterpart. To cover >90% of the UK's topology (>97% population coverage) with 3G cellular technology will requires in excess of 12,000 radio base stations per operator network. In 2001, there were around 25,000 established sites and, with an anticipated degree of collocation by necessity, that figure is forecast to rise to >47,000. Of course, the vast majority of these sites have a convenient grid connection. However, it is easy to see that the combination of wind and PV power generation and an energy storage system may be an

Dynamic Reactive Power Compensation of Large Scale Wind Integrated Power System

DEFF Research Database (Denmark)

Rather, Zakir Hussain; Chen, Zhe; Thøgersen, Paul

2015-01-01

wind turbines especially wind farms with additional grid support functionalities like dynamic support (e,g dynamic reactive power support etc.) and ii) refurbishment of existing conventional central power plants to synchronous condensers could be one of the efficient, reliable and cost effective option......Due to progressive displacement of conventional power plants by wind turbines, dynamic security of large scale wind integrated power systems gets significantly compromised. In this paper we first highlight the importance of dynamic reactive power support/voltage security in large scale wind...... integrated power systems with least presence of conventional power plants. Then we propose a mixed integer dynamic optimization based method for optimal dynamic reactive power allocation in large scale wind integrated power systems. One of the important aspects of the proposed methodology is that unlike...

Measurement-based harmonic current modeling of mobile storage for power quality study in the distribution system

Directory of Open Access Journals (Sweden)

Wenge Christoph

2017-12-01

Full Text Available Electric vehicles (EVs can be utilized as mobile storages in a power system. The use of battery chargers can cause current harmonics in the supplied AC system. In order to analyze the impact of different EVs with regardto their number and their emission of current harmonics, a generic harmonic current model of EV types was built and implemented in the power system simulation tool PSS®NETOMAC. Based on the measurement data for different types of EVs three standardized harmonic EV models were developed and parametrized. Further, the identified harmonic models are used by the computation of load flow in a modeled, German power distribution system. As a benchmark, a case scenario was studied regarding a high market penetration of EVs in the year 2030 for Germany. The impact of the EV charging on the power distribution system was analyzed and evaluated with valid power quality standards.

Optimal Operation of Plug-In Electric Vehicles in Power Systems with High Wind Power Penetrations

DEFF Research Database (Denmark)

Hu, Weihao; Su, Chi; Chen, Zhe

2013-01-01

in the power systems with high wind power penetrations. In this paper, the integration of plug-in electric vehicles in the power systems with high wind power penetrations is proposed and discussed. Optimal operation strategies of PEV in the spot market are proposed in order to decrease the energy cost for PEV......The Danish power system has a large penetration of wind power. The wind fluctuation causes a high variation in the power generation, which must be balanced by other sources. The battery storage based Plug-In Electric Vehicles (PEV) may be a possible solution to balance the wind power variations...... owners. Furthermore, the application of battery storage based aggregated PEV is analyzed as a regulation services provider in the power system with high wind power penetrations. The western Danish power system where the total share of annual wind power production is more than 27% of the electrical energy...

Price-based optimal control of electrical power systems

NARCIS (Netherlands)

Jokic, A.

2007-01-01

During the past decade, electrical power systems have been going through some major restructuring processes. From monopolistic, highly regulated and one utility controlled operation, a system is being restructured to include many parties competing for energy production and consumption, and for

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.

Modeling on a PWR power conversion system with system program

International Nuclear Information System (INIS)

Gao Rui; Yang Yanhua; Lin Meng

2007-01-01

Based on the power conversion system of nuclear and conventional islands of Daya Bay Power Station, this paper models the thermal-hydraulic systems of primary and secondary loops for PWR by using the PWR best-estimate program-RELAP5. To simulate the full-scope power conversion system, not only the traditional basic system models of nuclear island, but also the major system models of conventional island are all considered and modeled. A comparison between the calculated results and the actual data of reactor demonstrates a fine match for Daya Bay Nuclear Power Station, and manifests the feasibility in simulating full-scope power conversion system of PWR by RELAP5 at the same time. (authors)

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.

Power system frequency estimation based on an orthogonal decomposition method

Science.gov (United States)

Lee, Chih-Hung; Tsai, Men-Shen

2018-06-01

In recent years, several frequency estimation techniques have been proposed by which to estimate the frequency variations in power systems. In order to properly identify power quality issues under asynchronously-sampled signals that are contaminated with noise, flicker, and harmonic and inter-harmonic components, a good frequency estimator that is able to estimate the frequency as well as the rate of frequency changes precisely is needed. However, accurately estimating the fundamental frequency becomes a very difficult task without a priori information about the sampling frequency. In this paper, a better frequency evaluation scheme for power systems is proposed. This method employs a reconstruction technique in combination with orthogonal filters, which may maintain the required frequency characteristics of the orthogonal filters and improve the overall efficiency of power system monitoring through two-stage sliding discrete Fourier transforms. The results showed that this method can accurately estimate the power system frequency under different conditions, including asynchronously sampled signals contaminated by noise, flicker, and harmonic and inter-harmonic components. The proposed approach also provides high computational efficiency.

Power control based on particle swarm optimization of grid-connected inverter for hybrid renewable energy system

International Nuclear Information System (INIS)

García-Triviño, Pablo; Gil-Mena, Antonio José; Llorens-Iborra, Francisco; García-Vázquez, Carlos Andrés; Fernández-Ramírez, Luis M.; Jurado, Francisco

2015-01-01

Highlights: • Three PSO-based PI controllers for a grid-connected inverter were presented. • Two online PSO-based PI controllers were compared with an offline PSO-tuned PI. • The HRES and the inverter were evaluated under power changes and grid voltage sags. • Online ITAE-based PSO reduced ITAE (current THD) by 15.24% (5.32%) versus offline one. - Abstract: This paper is focused on the study of particle swarm optimization (PSO)-based PI controllers for the power control of a grid-connected inverter supplied from a hybrid renewable energy system. It is composed of two renewable energy sources (wind turbine and photovoltaic – PV – solar panels) and two energy storage systems (battery and hydrogen system, integrated by fuel cell and electrolyzer). Three PSO-based PI controllers are implemented: (1) conventional PI controller with offline tuning by PSO algorithm based on the integral time absolute error (ITAE) index; (2) PI controllers with online self-tuning by PSO algorithm based on the error; and (3) PI controllers with online self-tuning by PSO algorithm based on the ITAE index. To evaluate and compare the three controllers, the hybrid renewable energy system and the grid-connected inverter are simulated under changes in the active and reactive power values, as well as under a grid voltage sag. The results show that the online PSO-based PI controllers that optimize the ITAE index achieves the best response

Digital simulation of power electronic systems

International Nuclear Information System (INIS)

Mehring, P.; Jentsch, W.; John, G.; Kraemer, D.

1981-01-01

The following paper contains the final report on the NETSIM-Project. The purpose of this project is to develop a special digital simulation system, which could serve as a base for routine application of simulation in planning and development of power electronic systems. The project is realized in two steps. First a basic network analysis system is established. With this system the basic models and methods in treating power electronic networks could be probed. The resulting system is then integrated into a general digital simulation system for continous systems (CSSL-System). This integrated simulation system allows for convenient modeling and simulation of power electronic systems. (orig.) [de

New architectures for space power systems

International Nuclear Information System (INIS)

Ehsani, M.; Patton, A.D.; Biglic, O.

1992-01-01

Electric power generation and conditioning have experienced revolutionary development over the past two decades. Furthermore, new materials such as high energy magnets and high temperature superconductors are either available or on the horizon. The authors' work is based on the promise that new technologies are an important driver of new power system concepts and architectures. This observation is born out by the historical evolution of power systems both in terrestrial and aerospace applications. This paper will introduce new approaches to designing space power systems by using several new technologies

Centralized vs decentralized lunar power system study

Science.gov (United States)

Metcalf, Kenneth; Harty, Richard B.; Perronne, Gerald E.

1991-09-01

Three power-system options are considered with respect to utilization on a lunar base: the fully centralized option, the fully decentralized option, and a hybrid comprising features of the first two options. Power source, power conditioning, and power transmission are considered separately, and each architecture option is examined with ac and dc distribution, high and low voltage transmission, and buried and suspended cables. Assessments are made on the basis of mass, technological complexity, cost, reliability, and installation complexity, however, a preferred power-system architecture is not proposed. Preferred options include transmission based on ac, transmission voltages of 2000-7000 V with buried high-voltage lines and suspended low-voltage lines. Assessments of the total cost associated with the installations are required to determine the most suitable power system.

Power system stabilizer control for wind power to enhance power system stability

OpenAIRE

Domínguez García, José Luís; Gomis Bellmunt, Oriol; Bianchi, Fernando Daniel; Sumper, Andreas

2011-01-01

The paper presents a small signal stability analysis for power systems with wind farm interaction. Power systems have damping oscillation modes that can be excited by disturbance or fault in the grid. The power converters of the wind farms can be used to reduce these oscillations and make the system more stable. These ideas are explored to design a power system stabilized (PSS) for a network with conventional generators and a wind farm in order to increase the damping of the oscillation...

Approach to developing reliable space reactor power systems

International Nuclear Information System (INIS)

Mondt, J.F.; Shinbrot, C.H.

1991-01-01

The Space Reactor Power System Project is in the engineering development phase of a three-phase program. During Phase II, the Engineering Development Phase, the SP-100 Project has defined and is pursuing a new approach to developing reliable power systems. The approach to developing such a system during the early technology phase is described in this paper along with some preliminary examples to help explain the approach. Developing reliable components to meet space reactor power system requirements is based on a top down systems approach which includes a point design based on a detailed technical specification of a 100 kW power system

A mid-term, market-based power systems planning model

International Nuclear Information System (INIS)

Koltsaklis, Nikolaos E.; Dagoumas, Athanasios S.; Georgiadis, Michael C.; Papaioannou, George; Dikaiakos, Christos

2016-01-01

Highlights: • A mid-term Energy Planning along with a Unit Commitment model is developed. • The model identifies the optimum interconnection capacity. • Electricity interconnections affect the power mix and the day-ahead spot price. • Renewables’ penetration has impacts on the power reserves and the CO_2 emissions. • Energy policy and fuel pricing can have significant impacts on the power mix. - Abstract: This paper presents a generic Mixed Integer Linear Programming (MILP) model that integrates a Mid-term Energy Planning (MEP) model, which implements generation and transmission system planning at a yearly level, with a Unit Commitment (UC) model, which performs the simulation of the Day-Ahead Electricity Market. The applicability of the proposed model is illustrated in a case study of the Greek interconnected power system. The aim is to evaluate a critical project in the Ten Year Network Development Plan (TYNDP) of the Independent Power Transmission System Operator S.A. (ADMIE), namely the electric interconnection of the Crete Island with the mainland electric system. The proposed modeling framework identifies the implementation (or not) of the interconnection of the Crete Island with the mainland electric system, as well as the optimum interconnection capacity. It also quantifies the effects on the Day-Ahead electricity market and on the energy mix. The paper demonstrates that the model can provide useful insights into the strategic and challenging decisions to be determined by investors and/or policy makers at a national and/or regional level, by providing the optimal energy roadmap and management, as well as clear price signals on critical energy projects under real operating and design constraints.

A simulation-based expert system for nuclear power plant diagnostics

International Nuclear Information System (INIS)

Hassberger, J.A.; Lee, J.C.

1989-01-01

An expert system for diagnosing operational transients in a nuclear power plant is discussed. Hypothesis and test is used as the problem-solving strategy with hypotheses generated by an expert system that monitors the plant for patterns of data symptomatic of known failure modes. Fuzzy logic is employed as the inferencing mechanism with two complementary implication schemes to handle scenarios involving competing failures. Hypothesis testing is performed. An artificial intelligence framework based on a critical functions approach is used to deal with the complexity of a nuclear plant. A prototype system for diagnosing transients in the reactor coolant system of a pressurized water reactor has been developed to test the algorithms described here. Results are presented for the diagnosis of data from the Three Mile Island Unit 2 loss-of-feedwater/small-break loss-of-collant accident

Power system dynamics and stability with synchrophasor measurement and power system toolbox

CERN Document Server

Sauer, Peter W; Chow, Joe H

2017-01-01

This new edition addresses the needs of dynamic modeling and simulation relevant to power system planning, design, and operation, including a systematic derivation of synchronous machine dynamic models together with speed and voltage control subsystems. Reduced-order modeling based on integral manifolds is used as a firm basis for understanding the derivations and limitations of lower-order dynamic models. Following these developments, a multi-machine model interconnected through the transmission network is formulated and simulated using numerical simulation methods. Energy function methods are discussed for direct evaluation of stability. Small-signal analysis is used for determining the electromechanical modes and mode-shapes, and for power system stabilizer design. Time-synchronized high-sampling-rate phasor measurement units (PMUs) to monitor power system disturbances ave been implemented throughout North America and many other countries. In this second edition, new chapters on synchrophasor measurement ...

Operational experience of air washer based ventilation system for power conditioning system of Indus-2

International Nuclear Information System (INIS)

Pandey, R.M.; Baghel, S.L.; Parate, J.K.; Ahlawat, Sandeep; Rawlani, B.K.; Chouksey, Sanjay

2015-01-01

Indus-2 Synchrotron Accelerator requires high quality conditioned uninterrupted AC mains power for their smooth and reliable operation. Three units of 1670 kVA and one unit of 1100 kVA capacity rotary uninterruptible power conditioning systems (UPS) were installed and commissioned. These UPS units require dust free and cool ambient conditions for smooth operation. In order to meet the ventilation requirements, an evaporative cooling system of 80000 cubic meter/hour capacity with filtration units was designed, installed and commissioned in February 2011 and is operational on round-the-clock basis. Evaporative cooling scheme was chosen as has various advantages over a refrigerated system like lower initial capital costs, lower energy usage, lower running costs, less greenhouse gas and it does not contribute to ozone depletion. The ventilation system filters the environment air in stages up to 5 micron level and being conditioned with an automatic controlled soft water circulating system with cooling pads. An instrumentation and control scheme is included in the system to provide the automation requirements for operating 24 x 7 through the year. All the mechanical, hydraulic and electrical devices are maintained by providing preventive maintenance work without affecting the accelerator machine operation. Availability and reliability of the system was analysed based on the failure data. In Year 2014, the ventilation system was upgraded to accommodate standby blower unit, coupling unit and improved quality of supply air with new air conditioning devices. The control panel monitors the condition of air in the UPS hall and maintainsup to 28°C air temperature and 85% maximum relative humidity in round-the clock shift with more than 98% operational reliability. In this paper, we present design philosophy, installation, instrumentation, testing, operation experience and availability of the ventilation system for Power Conditioning System, Indus complex. (author)

Robust decentralised PI based LFC design for time delay power systems

International Nuclear Information System (INIS)

Bevrani, Hassan; Hiyama, Takashi

2008-01-01

In this paper, two robust decentralised proportional integral (PI) control designs are proposed for load frequency control (LFC) with communication delays. In both methodologies, the PI based LFC problem is reduced to a static output feedback (SOF) control synthesis for a multiple delay system. The first one is based on the optimal H ∞ control design using a linear matrix inequalities (LMI) technique. The second control design gives a suboptimal solution using a developed iterative linear matrix inequalities (ILMI) algorithm via the mixed H 2 /H ∞ control technique. The control strategies are suitable for LFC applications that usually employ PI control. The proposed control strategies are applied to a three control area power system with time delays and load disturbance to demonstrate their robustness

Nuclear power project management information system

International Nuclear Information System (INIS)

Zou Lailong; Zhang Peng; Xiao Ziyan; Chun Zengjun; Huang Futong

2001-01-01

Project Management Information System is an important infrastructure facility for the construction and operation of Nuclear Power Station. Based on the practice of Lingao nuclear power project management information system (NPMIS), the author describes the NPMIS design goals, system architecture and software functionality, points out the outline issues during the development and deployment of NPMIS

User Context Aware Base Station Power Flow Model

OpenAIRE

Walsh, Barbara; Farrell, Ronan

2005-01-01

At present the testing of power amplifiers within base station transmitters is limited to testing at component level as opposed to testing at the system level. While the detection of catastrophic failure is possible, that of performance degradation is not. This paper proposes a base station model with respect to transmitter output power with the aim of introducing system level monitoring of the power amplifier behaviour within the base station. Our model reflects the expe...

Stockholm Power Tech. Power systems

Energy Technology Data Exchange (ETDEWEB)

NONE

1995-11-01

The proceedings from this symposium is presented in six volumes: Invited speakers` sessions; Power systems; Power electronics; High-voltage technology; Electrical machines and drives; and Information and control systems. This report covers the power systems volume. Separate abstracts have been prepared for 141 of the 145 papers in this volume

Stockholm Power Tech. Power systems

International Nuclear Information System (INIS)

1995-01-01

The proceedings from this symposium is presented in six volumes: Invited speakers' sessions; Power systems; Power electronics; High-voltage technology; Electrical machines and drives; and Information and control systems. This report covers the power systems volume. Separate abstracts have been prepared for 141 of the 145 papers in this volume

Multi-megawatt power system trade study

Science.gov (United States)

Longhurst, Glen R.; Schnitzler, Bruce G.; Parks, Benjamin T.

2002-01-01

A concept study was undertaken to evaluate potential multi-megawatt power sources for nuclear electric propulsion. The nominal electric power requirement was set at 15 MWe with an assumed mission profile of 120 days at full power, 60 days in hot standby, and another 120 days of full power, repeated several times for 7 years of service. Two configurations examined were (1) a gas-cooled reactor based on the NERVA Derivative design, operating a closed cycle Brayton power conversion system; and (2) a molten metal-cooled reactor based on SP-100 technology, driving a boiling potassium Rankine power conversion system. This study considered the relative merits of these two systems, seeking to optimize the specific mass. Conclusions were that either concept appeared capable of reaching the specific mass goal of 3-5 kg/kWe estimated to be needed for this class of mission, though neither could be realized without substantial development in reactor fuels technology, thermal radiator mass and volume efficiency, and power conversion and distribution electronics and systems capable of operating at high temperatures. The gas-Brayton system showed a specific mass advantage (3.17 vs 6.43 kg/kWe for the baseline cases) under the set of assumptions used and eliminated the need to deal with two-phase working fluid flows in the microgravity environment of space. .

Fuzzy-logic-based power control system for multifield electrostatic precipitators

Energy Technology Data Exchange (ETDEWEB)

Grass, N. [Siemens AG, Erlangen (Germany)

2002-10-01

The power consumption of large precipitators can be in the range of 1 MW and above. Depending on the dust load properties, the electrical power may be reduced by up to 50% by applying fuzzy logic, without significantly increasing the dust emissions. The new approach uses fuzzy logic for optimization of existing electrostatic precipitators. The software runs on a standard personal computer platform under the, Windows NT operating system. The controllers of the electrostatic precipitator power supplies are linked to the personal computer via an industrial network (e.g., PROFIBUS). The system determines online the differentials of emission versus electrical power of each field. This measurement is difficult because of overlaid events in the other zones, and process changes. The long response time of the resultant dust emission due to electrical power changes in the precipitator is an additional complication. Rules were defined for a coarse, but fast-response power adaptation of all zones. Fine tuning the running system after the coarse optimization increased the accuracy and reliability. When installed on a 4 x 5 zone precipitator in a power station, significant results were obtained. The power savings over three months of operation were in the range of 40%-60% depending on the load and fuel characteristics. Data were recorded over the test period of three months. The results are presented.

Distance relay performance in future converter dominated power systems

DEFF Research Database (Denmark)

Sarkar, Moumita; Jia, Jundi; Yang, Guangya

2017-01-01

Increasing penetration of converter-based generations in power system has led to new system challenges. Short circuit power response from converter-based generations is different from that of traditional synchronous generators. Power electronic converters can be designed for over-current only up ...... of converter controls on fault current response of converter-based generations is also investigated. Index Terms—Converter control, distance relays, power system protection, system modelling....... to 1.1-1.25 times of its nominal value. Low availability of short circuit power can cause many challenges such as misoperation of distance relays. The aim of this paper is to investigate the effect of converter dominated systems on performance of distance relays. Backup functionality of the distance...... relay is major concern as miscoordination of backup relays in case of cascading faults can lead to severe stress in system, which can develop into blackout. In this paper, response of relays in traditional system is compared with response of relays in low short-circuit-current power systems. Impact...

UNISAT-3 Power System

Science.gov (United States)

Santoni, Fabio; Piergentili, Fabrizio; Bulgarelli, Fabio; Graziani, Filippo

2005-05-01

An overview of the UNISAT-3 microsatellite power subsystem is given. This is an educational, low weight and low cost microsatellite designed, built, launched and operated in space by students and professors of Scuola di Ingegneria Aerospaziale, at University of Rome "La Sapienza". The satellite power system is based on terrestrial technology solar arrays and NiCd batteries. The microsatellite hosts other solar arrays, including multi-junction solar cells and mono- crystalline silicon high efficiency solar cells, in order to compare their behaviour in orbit. Moreover a MPPT (Maximum Power Point Tracking ) system has been designed and tested, and it is a technological payload of UNISAT-3. The MPPT design follows the studies performed in the field of solar powered racing cars, with modifications to make the system suitable for use in space. The system design, numerical simulation and hardware ground testing are described in the paper. The experiment and the performance evaluation criterion are described, together with the preliminary results of the first eight months of operation in orbit.

Mobile nuclear power systems

International Nuclear Information System (INIS)

Andersson, B.

1988-11-01

This report is meant to present a general survey of the mobile nuclear power systems and not a detailed review of their technical accomplishments. It is based in published material mainly up to 1987. Mobile nuclear power systems are of two fundamentally different kinds: nuclear reactors and isotopic generators. In the reactors the energy comes from nuclear fission and in the isotopic generators from the radioactive decay of suitable isotopes. The reactors are primarily used as power sourves on board nuclear submarines and other warships but have also been used in the space and in remote places. Their thermal power has ranged from 30 kWth (in a satellite) to 175 MWth (on board an aircraft carrier). Isotopic generators are suitable only for small power demands and have been used on board satellites and spaceprobes, automatic weatherstations, lighthouses and marine installations for navigation and observation. (author)

An Inductive Link-Based Wireless Power Transfer System for Biomedical Applications

Directory of Open Access Journals (Sweden)

M. A. Adeeb

2012-01-01

Full Text Available A wireless power transfer system using an inductive link has been demonstrated for implantable sensor applications. The system is composed of two primary blocks: an inductive power transfer unit and a backward data communication unit. The inductive link performs two functions: coupling the required power from a wireless power supply system enabling battery-less, long-term implant operation and providing a backward data transmission path. The backward data communication unit transmits the data to an outside reader using FSK modulation scheme via the inductive link. To demonstrate the operation of the inductive link, a board-level design has been implemented with high link efficiency. Test results from a fabricated sensor system, composed of a hybrid implementation of custom-integrated circuits and board-level discrete components, are presented demonstrating power transmission of 125 mW with a 12.5% power link transmission efficiency. Simultaneous backward data communication involving a digital pulse rate of up to 10 kbps was also observed.

Design of a nonlinear backstepping control strategy of grid interconnected wind power system based PMSG

Science.gov (United States)

Errami, Y.; Obbadi, A.; Sahnoun, S.; Benhmida, M.; Ouassaid, M.; Maaroufi, M.

2016-07-01

This paper presents nonlinear backstepping control for Wind Power Generation System (WPGS) based Permanent Magnet Synchronous Generator (PMSG) and connected to utility grid. The block diagram of the WPGS with PMSG and the grid side back-to-back converter is established with the dq frame of axes. This control scheme emphasises the regulation of the dc-link voltage and the control of the power factor at changing wind speed. Besides, in the proposed control strategy of WPGS, Maximum Power Point Tracking (MPPT) technique and pitch control are provided. The stability of the regulators is assured by employing Lyapunov analysis. The proposed control strategy for the system has been validated by MATLAB simulations under varying wind velocity and the grid fault condition. In addition, a comparison of simulation results based on the proposed Backstepping strategy and conventional Vector Control is provided.

Dynamic security issues in autonomous power systems with increasing wind power penetration

DEFF Research Database (Denmark)

Margaris, I.D.; Hansen, Anca Daniela; Sørensen, Poul Ejnar

2011-01-01

Asynchronous Generator (DFAG) and Permanent Magnet Synchronous Generator (PMSG) – are applied and issues regarding interaction with the power system are investigated. This paper provides conclusions about the dynamic security of non-interconnected power systems with high wind power penetration based...... on a complete model representation of the individual components of the system; three different types of conventional generators are included in the model, while the protection system is also incorporated. The load shedding following faults is finally discussed....

Investigations on an advanced power system based on a high temperature polymer electrolyte membrane fuel cell and an organic Rankine cycle for heating and power production

International Nuclear Information System (INIS)

Perna, Alessandra; Minutillo, Mariagiovanna; Jannelli, Elio

2015-01-01

Energy systems based on fuel cells technology can have a strategic role in the range of small-size power generation for the sustainable energy development. In order to enhance their performance, it is possible to recover the “waste heat” from the fuel cells, for producing or thermal power (cogeneration systems) or further electric power by means of a bottoming power cycle (combined systems). In this work an advanced system based on the integration between a HT-PEMFC (high temperature polymer electrolyte membrane fuel cell) power unit and an ORC (organic Rankine cycle) plant, has been proposed and analysed as suitable energy power plant for supplying electric and thermal energies to a stand-alone residential utility. The system can operate both as cogeneration system, in which the electric and thermal loads are satisfied by the HT-PEMFC power unit and as electric generation system, in which the low temperature heat recovered from the fuel cells is used as energy source in the ORC plant for increasing the electric power production. A numerical model, able to characterize the behavior and to predict the performance of the HT-PEMFC/ORC system under different working conditions, has been developed by using the AspenPlus™ code. - Highlights: • The advanced plant can operate both as CHP system and as electric generation system. • The performance prediction of the integrated system is carried out by numerical modeling. • ORC thermodynamic optimization is carried out by a sensitivity analysis. • Thermal coupling between the HT-PEMC system and the ORC plant is analyzed. • Results are very promising in the field of the distributed generation

Development of a web-based monitoring system using operation parameters for the main component in nuclear power plants

Energy Technology Data Exchange (ETDEWEB)

Son, Dong Chan; An Kang Il; Hong, Suk Young; Lee, Jeong Soo; Lee, Kwang Yeol; Shin, Sun Hee; Lee, Chun Wha; Son, So Hee [Daesang Information Technology Co., Ltd., Seoul (Korea, Republic of)

2003-03-15

The frequency of the damage is increasing, which is caused by the fatigue, according to the increase of running of nuclear power plants. So we need to acquire the reliance of design data to estimate the fatigue and damage of major machinery that might happen as time-dependent crack growth characterization. The research is focused on keeping operating record of nuclear power plants about major machinery which consists of a nuclear reactor pressure boarder on each excessive operating condition including normal operating and extraordinary operating by estimating fracture mechanical movements on real time and fatigue about major nuclear power plants machinery, which are acquired the pressure and temperature data. For further details about the scope and contents of R and D are following: development of H/W that is necessary to acquire operating real time data of heating and hydraulic power, selection of a safety variable about major system by each type (the fourth unit), communication protocol development for connecting between CARE system data base server and fatigue monitoring system data base server, development of connecting database for controlling and storing of heating and hydraulic power operating data, real time monitoring system development based on web using JAVA.

Intelligent Control and Protection Methods for Modern Power Systems Based on WAMS

DEFF Research Database (Denmark)

Liu, Leo

Continuously growing demand for electricity, driven by deregulated power markets, has forced power systems to operate closer to their security operation limits. Meanwhile, the increasing penetration of large scale renewable energy may impact the operation of power systems by bringing more...... vulnerability indices i.e. structural vulnerability index (SVI), contingency vulnerability index (CVI) and operational vulnerability index (OVI) are proposed to evaluate the impact of distributed generation (DG) on power system vulnerability. The assessment shows that DG units are able to shorten the electrical...... influencing factors to power system transient stability are also evaluated, e.g. power output of generators in central power plants (CPP), load consumption level and the power exchange in high voltage direct current (HVDC) links. Both structural and dynamic vulnerability assessment, aiming at providing...

Electric power system / emergency power supply

International Nuclear Information System (INIS)

Dorn, P.G.

1980-01-01

One factor of reliability of reactor safety systems is the integrity of the power supply. The purpose of this paper is a review and a discussion of the safety objectives required for the planning, licensing, manufacture and erection of electrical power systems and components. The safety aspects and the technical background of the systems for - the electric auxiliary power supply system and - the emergency power supply system are outlined. These requirements result specially from the safety standards which are the framework for the studies of safety analysis. The overall and specific requirements for the electrical power supply of the safety systems are demonstrated on a 1300 MW standard nuclear power station with a pressurized water reactor. (orig.)

Energy Storage in Power System Operation: The Power Nodes Modeling Framework

DEFF Research Database (Denmark)

Heussen, Kai; Koch, Stephan; Ulbig, Andreas

2010-01-01

for designing operation strategies for power systems based on ubiquitous energy storage, for example to buer non-dispatchable generation, as well as for the evaluation of the operational performance in terms of energy eciency, reliability and cost. After introducing the modeling approach and a categorization......In this paper, a novel concept for the description of energy storage in power systems with dispatchable and non-dispatchable generators and loads is presented. It is based on a system-perspective consideration of energy storage, generation and consumption. This means that grid-relevant aspects...

Power fluctuation reduction methodology for the grid-connected renewable power systems

Science.gov (United States)

Aula, Fadhil T.; Lee, Samuel C.

2013-04-01

This paper presents a new methodology for eliminating the influence of the power fluctuations of the renewable power systems. The renewable energy, which is to be considered an uncertain and uncontrollable resource, can only provide irregular electrical power to the power grid. This irregularity creates fluctuations of the generated power from the renewable power systems. These fluctuations cause instability to the power system and influence the operation of conventional power plants. Overall, the power system is vulnerable to collapse if necessary actions are not taken to reduce the impact of these fluctuations. This methodology aims at reducing these fluctuations and makes the generated power capability for covering the power consumption. This requires a prediction tool for estimating the generated power in advance to provide the range and the time of occurrence of the fluctuations. Since most of the renewable energies are weather based, as a result a weather forecast technique will be used for predicting the generated power. The reduction of the fluctuation also requires stabilizing facilities to maintain the output power at a desired level. In this study, a wind farm and a photovoltaic array as renewable power systems and a pumped-storage and batteries as stabilizing facilities are used, since they are best suitable for compensating the fluctuations of these types of power suppliers. As an illustrative example, a model of wind and photovoltaic power systems with battery energy and pumped hydro storage facilities for power fluctuation reduction is included, and its power fluctuation reduction is verified through simulation.

Model-based reasoning technology for the power industry

International Nuclear Information System (INIS)

Touchton, R.A.; Subramanyan, N.S.; Naser, J.A.

1991-01-01

This paper reports on model-based reasoning which refers to an expert system implementation methodology that uses a model of the system which is being reasoned about. Model-based representation and reasoning techniques offer many advantages and are highly suitable for domains where the individual components, their interconnection, and their behavior is well-known. Technology Applications, Inc. (TAI), under contract to the Electric Power Research Institute (EPRI), investigated the use of model-based reasoning in the power industry including the nuclear power industry. During this project, a model-based monitoring and diagnostic tool, called ProSys, was developed. Also, an alarm prioritization system was developed as a demonstration prototype

PI2 controller based coordinated control with Redox Flow Battery and Unified Power Flow Controller for improved Restoration Indices in a deregulated power system

Directory of Open Access Journals (Sweden)

R. Thirunavukarasu

2016-12-01

Full Text Available The nature of power system restoration problem involves status assessment, optimization of generation capability and load pickup. This paper proposes the evaluation of Power System Restoration Indices (PSRI based on the Automatic Generation Control (AGC assessment of interconnected power system in a deregulated environment. The PSRI are useful for system planners to prepare the power system restoration plans and to improve the efficiency of the physical operation of the power system with the increased transmission capacity in the network. The stabilization of frequency and tie-line power oscillations in an interconnected power system becomes challenging when implemented in the future competitive environment. This paper also deals with the concept of AGC in two-area reheat power system having coordinated control action with Redox Flow Battery (RFB and Unified Power Flow Controller (UPFC are capable of controlling the network performance in a very fast manner and improve power transfer limits in order to have a better restoration. In addition to that a new Proportional–Double Integral (PI2 controller is designed and implemented in AGC loop and controller parameters are optimized through Bacterial Foraging Optimization (BFO algorithm. Simulation results reveal that the proposed PI2 controller is that it has good stability during load variations, excellent transient and dynamic responses when compared with the system comprising PI controller. Moreover the AGC loop with RFB coordinated with UPFC has greatly improved the dynamic response and it reduces the control input requirements, to ensure improved PSRI in order to provide the reduced restoration time, thereby improving the system reliability.

Analysis on nuclear power plant control room system design and improvement based on human factor engineering

International Nuclear Information System (INIS)

Gao Feng; Liu Yanzi; Sun Yongbin

2014-01-01

The design of nuclear power plant control room system is a process of improvement with the implementation of human factor engineering theory and guidance. The method of implementation human factor engineering principles into the nuclear power plant control room system design and improvement was discussed in this paper. It is recommended that comprehensive address should be done from control room system function, human machine interface, digital procedure, control room layout and environment design based on the human factor engineering theory and experience. The main issues which should be paid more attention during the control room system design and improvement also were addressed in this paper, and then advices and notices for the design and improvement of the nuclear power plant control room system were afforded. (authors)

Design of a telemetry system based on wireless power transmission for physiological parameter monitoring

International Nuclear Information System (INIS)

Jia, Zhiwei; Yan, Guozheng; Zhu, Bingquan

2015-01-01

An implanted telemetry system for experimental animals with or without anaesthesia can be used to continuously monitor physiological parameters. This system is significant not only in the study of organisms but also in the evaluation of drug efficacy, artificial organs, and auxiliary devices. The system is composed of a miniature electronic capsule, a wireless power transmission module, a data-recording device, and a processing module. An electrocardiograph, a temperature sensor, and a pressure sensor are integrated in the miniature electronic capsule, in which the signals are transmitted in vitro by wireless communication after filtering, amplification, and A/D sampling. To overcome the power shortage of batteries, a wireless power transmission module based on electromagnetic induction was designed. The transmitting coil of a rectangular-section solenoid and a 3D receiving coil are proposed according to stability and safety constraints. Experiments show that at least 150 mW of power could pick up on the load in a volume of Φ10.5 mm × 11 mm, with a transmission efficiency of 2.56%. Vivisection experiments verified the feasibility of the integrated radio-telemetry system

Design of a telemetry system based on wireless power transmission for physiological parameter monitoring

Energy Technology Data Exchange (ETDEWEB)

Jia, Zhiwei, E-mail: jiayege@hotmail.com [College of Electrical and Information Engineering, Changsha University of Science and Technology, Changsha (China); Yan, Guozheng; Zhu, Bingquan [820 Institute, School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai (China)

2015-04-15

An implanted telemetry system for experimental animals with or without anaesthesia can be used to continuously monitor physiological parameters. This system is significant not only in the study of organisms but also in the evaluation of drug efficacy, artificial organs, and auxiliary devices. The system is composed of a miniature electronic capsule, a wireless power transmission module, a data-recording device, and a processing module. An electrocardiograph, a temperature sensor, and a pressure sensor are integrated in the miniature electronic capsule, in which the signals are transmitted in vitro by wireless communication after filtering, amplification, and A/D sampling. To overcome the power shortage of batteries, a wireless power transmission module based on electromagnetic induction was designed. The transmitting coil of a rectangular-section solenoid and a 3D receiving coil are proposed according to stability and safety constraints. Experiments show that at least 150 mW of power could pick up on the load in a volume of Φ10.5 mm × 11 mm, with a transmission efficiency of 2.56%. Vivisection experiments verified the feasibility of the integrated radio-telemetry system.

Technical impacts of high penetration levels of wind power on power system stability

OpenAIRE

Flynn, Damian; Rather, Z.; Ardal, Atle; Darco, Salvatore; Hansen, Anca Daniela; Cutululis, Nicolaos Antonio; Sørensen, Poul Ejnar; Estanqueiro, Ana; Gomez, Emilio; Menemenlis, Nickie; Smith, Charlie; Wang, Ye

2017-01-01

With increasing penetrations of wind generation, based on power-electronic converters, power systems are transitioning away from well-understood synchronous generator-based systems, with growing implications for their stability. Issues of concern will vary with system size, wind penetration level, geographical distribution and turbine type, network topology, electricity market structure, unit commitment procedures, and other factors. However, variable-speed wind turbines, both onshore and con...

Systems aspects of a space nuclear reactor power system

Science.gov (United States)

Jaffe, L.; Fujita, T.; Beatty, R.; Bhandari, P.; Chow, E.; Deininger, W.; Ewell, R.; Grossman, M.; Bloomfield, H.; Heller, J.

1988-01-01

Various system aspects of a 300-kW nuclear reactor power system for spacecraft have been investigated. Special attention is given to the cases of a reusable OTV and a space-based radar. It is demonstrated that the stowed length of the power system is important to mission design, and that orbital storage for months to years may be needed for missions involving orbital assembly.

MOCA: A Low-Power, Low-Cost Motion Capture System Based on Integrated Accelerometers

Directory of Open Access Journals (Sweden)

Elisabetta Farella

2007-01-01

Full Text Available Human-computer interaction (HCI and virtual reality applications pose the challenge of enabling real-time interfaces for natural interaction. Gesture recognition based on body-mounted accelerometers has been proposed as a viable solution to translate patterns of movements that are associated with user commands, thus substituting point-and-click methods or other cumbersome input devices. On the other hand, cost and power constraints make the implementation of a natural and efficient interface suitable for consumer applications a critical task. Even though several gesture recognition solutions exist, their use in HCI context has been poorly characterized. For this reason, in this paper, we consider a low-cost/low-power wearable motion tracking system based on integrated accelerometers called motion capture with accelerometers (MOCA that we evaluated for navigation in virtual spaces. Recognition is based on a geometric algorithm that enables efficient and robust detection of rotational movements. Our objective is to demonstrate that such a low-cost and a low-power implementation is suitable for HCI applications. To this purpose, we characterized the system from both a quantitative point of view and a qualitative point of view. First, we performed static and dynamic assessment of movement recognition accuracy. Second, we evaluated the effectiveness of user experience using a 3D game application as a test bed.

Towards a Danish power system with 50% wind

DEFF Research Database (Denmark)

Xu, Zhao; Gordon, Mark; Lind, Morten

2009-01-01

The new Danish Energy Strategy implies 50% wind power penetration for the Danish electric power system by 2025. Accordingly, it is the vision to develop the Danish electric power system into world's best renewable based electricity system, and many research and development activities have taken...

Design and application of the high-voltage DC power-supply control system based on PLC

International Nuclear Information System (INIS)

Huang Yiyun; Zheng Guanghua; Wu Junshuan; Yang Chunsheng; Hu Huaichuan

2002-03-01

The design and application of A kind of high-voltage DC power-supply control system based on PLC is referred, in addition, KingView is used to monitor the system in real time and manage the man-machine conversation ideally

Solar dynamic power system definition study

Science.gov (United States)

Wallin, Wayne E.; Friefeld, Jerry M.

1988-01-01

The solar dynamic power system design and analysis study compared Brayton, alkali-metal Rankine, and free-piston Stirling cycles with silicon planar and GaAs concentrator photovoltaic power systems for application to missions beyond the Phase 2 Space Station level of technology for all power systems. Conceptual designs for Brayton and Stirling power systems were developed for 35 kWe and 7 kWe power levels. All power systems were designed for 7-year end-of-life conditions in low Earth orbit. LiF was selected for thermal energy storage for the solar dynamic systems. Results indicate that the Stirling cycle systems have the highest performance (lowest weight and area) followed by the Brayton cycle, with photovoltaic systems considerably lower in performance. For example, based on the performance assumptions used, the planar silicon power system weight was 55 to 75 percent higher than for the Stirling system. A technology program was developed to address areas wherein significant performance improvements could be realized relative to the current state-of-the-art as represented by Space Station. In addition, a preliminary evaluation of hardenability potential found that solar dynamic systems can be hardened beyond the hardness inherent in the conceptual designs of this study.

Analysis of power system collapse risk

International Nuclear Information System (INIS)

Eleschova, Z.; Belan, A.; Cintula, B.; Smitkova, M.

2012-01-01

In this paper are analysed the initialization events with considering different scenarios and their impact on the power system transient stability. As an initialization event is considered a short circuit at various places of power line. In each scenario are considered protection failures (backup protection), circuit-breaker failures (breaker failure relay activation). The individual states are analysed and the power system collapse risk assessed based on the simulation experiments results (Authors)

Analysis of Stationary, Photovoltaic-based Surface Power System Designs at the Lunar South Pole

Science.gov (United States)

Freeh, Joshua E.

2009-01-01

Combinations of solar arrays and either batteries or regenerative fuel cells are analyzed for a surface power system module at the lunar south pole. The systems are required to produce 5 kW of net electrical power in sunlight and 2 kW of net electrical power during lunar night periods for a 10-year period between 2020 and 2030. Systems-level models for energy conservation, performance, degradation, and mass are used to compare to various systems. The sensitivities of important and/or uncertain variables including battery specific energy, fuel cell operating voltage, and DC-DC converter efficiency are compared to better understand the system. Switching unit efficiency, battery specific energy, and fuel cell operating voltage appear to be important system-level variables for this system. With reasonably sized solar arrays, the regenerative fuel cell system has significantly lower mass than the battery system based on the requirements and assumptions made herein. The total operational time is estimated at about 10,000 hours in battery discharge/fuel cell mode and about 4,000 and 8,000 hours for the battery charge and electrolyzer modes, respectively. The estimated number of significant depth-of-discharge cycles for either energy storage system is less than 100 for the 10-year period.

Partial analysis of wind power limit in an electric micro system using continuation power flow

International Nuclear Information System (INIS)

Fiallo Guerrero, Jandry; Santos Fuentefria, Ariel; Castro Fernández, Miguel

2013-01-01

The wind power insertion in the power system is an important issue and can create some instability problems in voltage and system frequency due to stochastic origin of wind. Know the Wind Power Limit that can insert in an electric grid without losing stability is a very important matter. Existing in bibliography a few methods for calculation of wind power limit, some of them are based in static constrains, an example is a method based in a continuation power flow analysis. In the present work the method is applied in an electric micro system formed when the system is disconnected of the man grid, the main goal was prove the method in a weak and island network. The software used in the simulations was the Power System Analysis Toolbox (PSAT). (author)

A bimodal power and propulsion system based on cermet fuel and heat pipe energy transport

International Nuclear Information System (INIS)

Polansky, G.F.; Gunther, N.A.; Rochow, R.F.; Bixler, C.H.

1995-01-01

Bimodal space reactor systems provide both thermal propulsion for the spacecraft orbital transfer and electrical power to the spacecraft bus once it is on station. These systems have the potential to increase both the available payload in high energy orbits and the available power to that payload. These increased mass and power capabilities can be used to either reduce mission cost by permitting the use of smaller launch vehicles or to provide increased mission performance from the current launch vehicle. A major barrier to the deployment of these bimodal systems has been the cost associated with their development. This paper describes a bimodal reactor system with performance potential to permit more than 70% of the instrumented payload of the Titan IV/Centaur to be launched from the Atlas IIAS. The development cost is minimized by basing the design on existing component technologies

A Fuzzy-Based PI Controller for Power Management of a Grid-Connected PV-SOFC Hybrid System

Directory of Open Access Journals (Sweden)

Shivashankar Sukumar

2017-10-01

Full Text Available Solar power generation is intermittent in nature. It is nearly impossible for a photovoltaic (PV system to supply power continuously and consistently to a varying load. Operating a controllable source like a fuel cell in parallel with PV can be a solution to supply power to variable loads. In order to coordinate the power supply from fuel cells and PVs, a power management system needs to be designed for the microgrid system. This paper presents a power management system for a grid-connected PV and solid oxide fuel cell (SOFC, considering variation in the load and solar radiation. The objective of the proposed system is to minimize the power drawn from the grid and operate the SOFC within a specific power range. Since the PV is operated at the maximum power point, the power management involves the control of SOFC active power where a proportional and integral (PI controller is used. The control parameters of the PI controller Kp (proportional constant and Ti (integral time constant are determined by the genetic algorithm (GA and simplex method. In addition, a fuzzy logic controller is also developed to generate appropriate control parameters for the PI controller. The performance of the controllers is evaluated by minimizing the integral of time multiplied by absolute error (ITAE criterion. Simulation results showed that the fuzzy-based PI controller outperforms the PI controller tuned by the GA and simplex method in managing the power from the hybrid source effectively under variations of load and solar radiation.

System and method for controlling power consumption in a computer system based on user satisfaction

Science.gov (United States)

Yang, Lei; Dick, Robert P; Chen, Xi; Memik, Gokhan; Dinda, Peter A; Shy, Alex; Ozisikyilmaz, Berkin; Mallik, Arindam; Choudhary, Alok

2014-04-22

Systems and methods for controlling power consumption in a computer system. For each of a plurality of interactive applications, the method changes a frequency at which a processor of the computer system runs, receives an indication of user satisfaction, determines a relationship between the changed frequency and the user satisfaction of the interactive application, and stores the determined relationship information. The determined relationship can distinguish between different users and different interactive applications. A frequency may be selected from the discrete frequencies at which the processor of the computer system runs based on the determined relationship information for a particular user and a particular interactive application running on the processor of the computer system. The processor may be adapted to run at the selected frequency.

Power system security enhancement with unified power flow controller under multi-event contingency conditions

Directory of Open Access Journals (Sweden)

S. Ravindra

2017-03-01

Full Text Available Power system security analysis plays key role in enhancing the system security and to avoid the system collapse condition. In this paper, a novel severity function is formulated using transmission line loadings and bus voltage magnitude deviations. The proposed severity function and generation fuel cost objectives are analyzed under transmission line(s and/or generator(s contingency conditions. The system security under contingency conditions is analyzed using optimal power flow problem. An improved teaching learning based optimization (ITLBO algorithm has been presented. To enhance the system security under contingency conditions in the presence of unified power flow controller (UPFC, it is necessary to identify an optimal location to install this device. Voltage source based power injection model of UPFC, incorporation procedure and optimal location identification strategy based on line overload sensitivity indexes are proposed. The entire proposed methodology is tested on standard IEEE-30 bus test system with supporting numerical and graphical results.