Reactive power compensation a practical guide

CERN Document Server

Hofmann, Wolfgang; Just, Wolfgang

2012-01-01

The comprehensive resource on reactive power compensation, presenting the design, application and operation of reactive power equipment and installations The area of reactive power compensation is gaining increasing importance worldwide. If suitably designed, it is capable of improving voltage quality significantly, meaning that losses in equipment and power systems are reduced, the permissible loading of equipment can be increased, and the over-all stability of system operation improved. Ultimately, energy use and CO2 emisson are reduced. This unique guide discusses the

Reactive Power Pricing Model Considering the Randomness of Wind Power Output

Science.gov (United States)

Dai, Zhong; Wu, Zhou

2018-01-01

With the increase of wind power capacity integrated into grid, the influence of the randomness of wind power output on the reactive power distribution of grid is gradually highlighted. Meanwhile, the power market reform puts forward higher requirements for reasonable pricing of reactive power service. Based on it, the article combined the optimal power flow model considering wind power randomness with integrated cost allocation method to price reactive power. Meanwhile, considering the advantages and disadvantages of the present cost allocation method and marginal cost pricing, an integrated cost allocation method based on optimal power flow tracing is proposed. The model realized the optimal power flow distribution of reactive power with the minimal integrated cost and wind power integration, under the premise of guaranteeing the balance of reactive power pricing. Finally, through the analysis of multi-scenario calculation examples and the stochastic simulation of wind power outputs, the article compared the results of the model pricing and the marginal cost pricing, which proved that the model is accurate and effective.

Effects of a power shortage in the Tokyo metropolitan area on awareness of nuclear power generation and power savings behavior

International Nuclear Information System (INIS)

Kitada, Atsuko

2004-01-01

The shutdown of a number of nuclear power stations of the Tokyo Electric Power Company in the summer of 2003 caused a power shortage problem in the Tokyo Metropolitan area. To examine the effects of the power shortage, in September 2003 a survey was conducted in the service areas of the Kansai Electric Power Company (Kansai region) and the Tokyo Electric Power Company (Kanto region). This survey was part of a wider opinion survey begun in 1993 concerning nuclear power generation. The results of the September 2003 survey are as follows: The degree of recognition of the power shortage problem in the Metropolitan area was high, with 40% of respondents in the Kansai region and nearly 70% in the Kanto region understanding that the shortage was caused by the shutdown of several nuclear power station. The overall awareness of nuclear power generation was little affected in both the Kansai and Kanto regions, though the sense of a shortage of the generating capacity had been raised slightly. Once respondents knew about the power shortage problem, they estimated the likelihood of an occurrence of large-scale service interruption to be low, nearly at an even chance, and they had been only slightly worried about it, essentially viewing the problem optimistically. In the Kanto region, where public relations activities for power savings had been actively pursued, the frequency of experiencing exposure to such public relations activities was remarkably higher than in the Kansai region. The relation between exposure to public relations activities for power savings and power savings behavior was analyzed using quantification method II. Analysis results suggest that public relations activities for power savings in the Kanto region had the effect of urging power savings behavior. However, the difference in the rate of putting power savings behavior into practice was small between the Kanto and Kansai regions, indicating that public relation activities for power savings in the Kanto

Coupled energy and reactive power market clearing considering power system security

International Nuclear Information System (INIS)

Rabiee, Abdorreza; Shayanfar, Heidarali; Amjady, Nima

2009-01-01

In a deregulated environment, when talking about electricity markets, one usually refers to energy market, paying less attention to the reactive power market. Active and reactive powers are, however, coupled through the AC power flow equations and branch loading limits as well as the synchronous generators capability curves. However, the sequential approach for energy and reactive power markets cannot present the optimal solution due to the interactions between these markets. For instance, clearing of the reactive power market can change active power dispatch (e.g. due to a change of transmission system losses and the capability curve limitation), which can lead to degradation of the energy market clearing point. This paper presents a coupled day ahead energy and reactive power market based on the pay-at-MCP settlement mechanism. Besides, the proposed coupled framework considers voltage stability and security issues and branch loading limits. The coupled market is cleared through optimal power flow (OPF). Its objective function includes total payment of generating units for their active power production along with the total payment function (TPF) of units for their reactive power compensation. Moreover, lost opportunity cost (LOC) of the units is also considered. The effectiveness of the proposed framework is examined on the IEEE 24 bus Reliability Test System

Coupled energy and reactive power market clearing considering power system security

Energy Technology Data Exchange (ETDEWEB)

Rabiee, Abdorreza; Shayanfar, Heidarali [Center of Excellence for Power System Automation and Operation, Electrical Engineering Department, Iran University of Science and Technology (IUST), Tehran (Iran); Amjady, Nima [Department of Electrical Engineering, Semnan University, Semnan (Iran)

2009-04-15

In a deregulated environment, when talking about electricity markets, one usually refers to energy market, paying less attention to the reactive power market. Active and reactive powers are, however, coupled through the AC power flow equations and branch loading limits as well as the synchronous generators capability curves. However, the sequential approach for energy and reactive power markets cannot present the optimal solution due to the interactions between these markets. For instance, clearing of the reactive power market can change active power dispatch (e.g. due to a change of transmission system losses and the capability curve limitation), which can lead to degradation of the energy market clearing point. This paper presents a coupled day ahead energy and reactive power market based on the pay-at-MCP settlement mechanism. Besides, the proposed coupled framework considers voltage stability and security issues and branch loading limits. The coupled market is cleared through optimal power flow (OPF). Its objective function includes total payment of generating units for their active power production along with the total payment function (TPF) of units for their reactive power compensation. Moreover, lost opportunity cost (LOC) of the units is also considered. The effectiveness of the proposed framework is examined on the IEEE 24 bus Reliability Test System. (author)

Evolution of China's power dispatch principle and the new energy saving power dispatch policy

International Nuclear Information System (INIS)

Ciwei, Gao; Yang, Li

2010-01-01

With social economic reform in the past decades, the power industry of China is gradually evolving from a highly integrated one toward an electricity market, which can be characterized based on the transition of the power dispatch principle. To attract investment in the power generating industry, China introduced non-state-owned power plants to the original system of a highly vertically integrated power industry with annual power generation quota guarantees, which makes the traditional economic dispatch principle not applicable. The newly debuted energy saving power dispatch (ESPD) is an attempt to fully exploit the maximum energy savings and was implemented by an administrative code. Starting in August 2007, the pilot operation of the ESPD was implemented in five provinces, but after two years, it is still not widely applied all over the country. This paper details the transition of China's power dispatch principle with particular attention to its origin and content. Moreover, the factors that influence the ESPD's actual energy saving effect are discussed, as well as the sustainability of the policy. (author)

Development of Android based Smart Power Saving System

Science.gov (United States)

Gupta, Ashutosh; Kumar, Pradeep; Ghosh, Tathagata; Bhawna, Shruthi. S.

2017-08-01

An android based smart power saving system has been presented in this paper. For this purpose, an application is developed for controlling the intensity of an AC supply using a dimmer circuit in android platform and to monitor the current flow on different intensity level a current sensor is used in the circuit. Dimmer circuit provides a 16-different intensity level to control the flow of current and help in power saving. The system is very simple and robust as it is based on android platform.

A New Framework for Reactive Power Market Considering Power System Security

Directory of Open Access Journals (Sweden)

A. Rabiee

2009-09-01

Full Text Available This paper presents a new framework for the day-ahead reactive power market based on the uniform auction price. Voltage stability and security have been considered in the proposed framework. Total Payment Function (TPF is suggested as the objective function of the Optimal Power Flow (OPF used to clear the reactive power market. Overload, voltage drop and voltage stability margin (VSM are included in the constraints of the OPF. Another advantage of the proposed method is the exclusion of Lost Opportunity Cost (LOC concerns from the reactive power market. The effectiveness of the proposed reactive power market is studied based on the CIGRÉ-32 bus test system.

Money in the bank : Feeling powerful increases saving

NARCIS (Netherlands)

Garbinsky, E.; Klesse, A.K.; Aaker, J.

2014-01-01

Across five studies, this research reveals that feeling powerful increases saving. This effect is driven by the desire to maintain one’s current state. When the purpose of saving is no longer to accumulate money but to spend it on a status-related product, the basic effect is reversed, and those who

Reactive power management of power networks with wind generation

CERN Document Server

Amaris, Hortensia; Ortega, Carlos Alvarez

2012-01-01

As the energy sector shifts and changes to focus on renewable technologies, the optimization of wind power becomes a key practical issue. Reactive Power Management of Power Networks with Wind Generation brings into focus the development and application of advanced optimization techniques to the study, characterization, and assessment of voltage stability in power systems. Recent advances on reactive power management are reviewed with particular emphasis on the analysis and control of wind energy conversion systems and FACTS devices. Following an introduction, distinct chapters cover the 5 key

Electric power production contra electricity savings

International Nuclear Information System (INIS)

Schleisner, L.; Grohnheit, P.E.; Soerensen, H.

1991-01-01

The expansion of electricity-producing plants has, in Denmark until now, taken place in accordance with the demand for electricity. Recently, it has been suggested that the cost of the further development of such systems is greater than the cost of instigating and carrying out energy conservation efforts. The aim of the project was to evaluate the consequences for power producing plants of a reduction of the electricity consumption of end-users. A method for the analysis of the costs involved in the system and operation of power plants contra the costs that are involved in saving electricity is presented. In developing a model of this kind, consideration is given to the interplay of the individual saving project and the existing or future electricity supply. Thus it can be evaluated to what extent it would be advisable to substitute investments in the development of the capacity of the power plants with investments in the reduction of electricity consumption by the end users. This model is described in considerable detail. It will be tested in representative situations and locations throughout the Nordic countries. (AB) 17 refs

Compensation of Reactive Power from Wind Turbines with Power Electronics Equipment

DEFF Research Database (Denmark)

Pedersen, Jørgen Kaas

1996-01-01

Wind turbines with induction generators consume reactive power. Apart from the no load consumption, which is nearing constant and is being compensated for using capacitors, the consumption of reactive power varies almost proportional with the power production, which can vary immensely. Except tha...

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...

An introduction to reactive power compensation for wind farms

Energy Technology Data Exchange (ETDEWEB)

Nigim, K.A. [Waterloo Univ., Ont. (Canada). Dept. of Electrical and Computer Engineering; Cairo Univ., Giza (Egypt). Faculty of Engineering; Zobaa, A.F.; El Amin, I. [King Fahd Univ. of Petroleum and Minerals, Dhahran (Saudi Arabia). Dept. of Electrical Engineering

2005-07-01

The paper summarises the refereed contributions of seven articles reviewed for publication in the IJETP - Special Issue on 'Reactive compensation for wind farms'. The main goal of the special issue is to provide a forum to exchange information on the reactive power compensation requirements for wind farms and introducing possible price mechanisms for today's deregulated power industry. Uncompensated reactive power causes stress on the hosting utility grid as well as added expenses, which create in difficulties for power purchasing agreements from independent wind energy producers. Wind power producers need to comply with the hosting utility grid interconnection standards, e.g., voltage and frequency, as well as to provide controllable active and reactive sources of power. Active power supply is mainly dependent on the potential of wind power produced and the turbine design. Reactive power demand on the other hand depends on the conversion devices and the recovered power quantity fed to the grid. Static Var Compensators (SVC), Unified Power Quality Conditioners (UPQC), Unified Power Flow Controllers (UPFC), and the Distributed Static Synchronous Compensators (DSTATCOM) are all new emerging devices aimed at regulating the reactive power requirements. The excellent controllability of these devices has paved the way to flexible and dynamic controllers that are capable of regulating the flow of active and reactive power components. These devices are now suggested for the control of the reactive power requirement of wind generators. Studies have demonstrated acceptable voltage stabilisation results. This has increased the penetration level of wind power into existing distribution networks in many countries. (Author)

An introduction to reactive power compensation for wind farms

International Nuclear Information System (INIS)

Nigim, K.A.; Cairo Univ., Giza; Zobaa, A.F.; El Amin, I.

2005-01-01

The paper summarises the refereed contributions of seven articles reviewed for publication in the IJETP - Special Issue on 'Reactive compensation for wind farms'. The main goal of the special issue is to provide a forum to exchange information on the reactive power compensation requirements for wind farms and introducing possible price mechanisms for today's deregulated power industry. Uncompensated reactive power causes stress on the hosting utility grid as well as added expenses, which create in difficulties for power purchasing agreements from independent wind energy producers. Wind power producers need to comply with the hosting utility grid interconnection standards, e.g., voltage and frequency, as well as to provide controllable active and reactive sources of power. Active power supply is mainly dependent on the potential of wind power produced and the turbine design. Reactive power demand on the other hand depends on the conversion devices and the recovered power quantity fed to the grid. Static Var Compensators (SVC), Unified Power Quality Conditioners (UPQC), Unified Power Flow Controllers (UPFC), and the Distributed Static Synchronous Compensators (DSTATCOM) are all new emerging devices aimed at regulating the reactive power requirements. The excellent controllability of these devices has paved the way to flexible and dynamic controllers that are capable of regulating the flow of active and reactive power components. These devices are now suggested for the control of the reactive power requirement of wind generators. Studies have demonstrated acceptable voltage stabilisation results. This has increased the penetration level of wind power into existing distribution networks in many countries. (Author)

Application of Newton's optimal power flow in voltage/reactive power control

Energy Technology Data Exchange (ETDEWEB)

Bjelogrlic, M.; Babic, B.S. (Electric Power Board of Serbia, Belgrade (YU)); Calovic, M.S. (Dept. of Electrical Engineering, University of Belgrade, Belgrade (YU)); Ristanovic, P. (Institute Nikola Tesla, Belgrade (YU))

1990-11-01

This paper considers an application of Newton's optimal power flow to the solution of the secondary voltage/reactive power control in transmission networks. An efficient computer program based on the latest achievements in the sparse matrix/vector techniques has been developed for this purpose. It is characterized by good robustness, accuracy and speed. A combined objective function appropriate for various system load levels with suitable constraints, for treatment of the power system security and economy is also proposed. For the real-time voltage/reactive power control, a suboptimal power flow procedure has been derived by using the reduced set of control variables. This procedure is based on the sensitivity theory applied to the determination of zones for the secondary voltage/reactive power control and corresponding reduced set of regulating sources, whose reactive outputs represent control variables in the optimal power flow program. As a result, the optimal power flow program output becomes a schedule to be used by operators in the process of the real-time voltage/reactive power control in both normal and emergency operating states.

APPLICATION OF MODIFIED POWER FLOW TRACING METHOD FOR REACTIVE POWER PRICING IN PRACTICAL UTILITY SYSTEM

Directory of Open Access Journals (Sweden)

M. SUSITHRA

2017-01-01

Full Text Available Competitive trend towards restructuring and unbundling of transmission services has resulted in the need to discover the impact of a particular generator to load. This paper initially presents the analysis of three different reactive power valuation methods namely, Modified Ybus , Virtual flow approach and modified power flow tracing to compute the reactive power output from a particular generator to particular load. Among these methods, the modified power flow electricity tracing method is identified as the best method to trace the reactive power contribution from various reactive power sources to loads, transmission line, etc. Also this proposed method breakdown the total reactive power loss in a transmission line into components to be allocated to individual loads. Secondly, based on this Method a novel allocation method for reactive power service for practical system is proposed. Hence, this method can be useful in providing additional insight into power system operation and can be used to modify existing tariffs of charging for reactive power transmission loss and reactive power transmission services. Simulation and comparison results are shown by taking WSCC 9 and IEEE 30 bus system as test system.

Reactive power control with CHP plants - A demonstration

DEFF Research Database (Denmark)

Nyeng, Preben; Østergaard, Jacob; Andersen, Claus A.

2010-01-01

power rating of 7.3 MW on two synchronous generators. A closed-loop control is implemented, that remote controls the CHP plant to achieve a certain reactive power flow in a near-by substation. The solution communicates with the grid operator’s existing SCADA system to obtain measurements from...... lines to underground cables has changed the reactive power balance, and third, the TSO has introduced restrictions in the allowed exchange of reactive power between the transmission system and distribution grids (known as the Mvar-arrangement). The demonstration includes a CHP plant with an electric......In this project the potential for ancillary services provision by distributed energy resources is investigated. Specifically, the provision of reactive power control by combined heat and power plants is examined, and the application of the new standard for DER communication systems, IEC 61850...

Design of reactive power procurement in deregulated electricity market

African Journals Online (AJOL)

Reactive power management is different in the deregulated electricity market of various countries. In this paper, a novel reactive power procurement model is proposed, which ensure secure and reliable operation of deregulated electricity market. Various issues of reactive power management in the deregulated electricity ...

Reactive power management and voltage control in deregulated power markets

Science.gov (United States)

Spangler, Robert G.

The research that is the subject of this dissertation is about the management of reactive power and voltage support in the wholesale open access power markets in the United States (US). The purpose of this research is to place decisions about open access market structures, as they relate to reactive power and voltage control, on a logical and consistent economic basis, given the engineering needs of a commercial electric power system. An examination of the electricity markets operating in the US today reveals that current approaches to reactive power management and voltage support are extensions of those based on historical, regulated monopoly electric service. A case for change is built by first looking at the subject of reactive power from an engineering viewpoint and then from an economic perspective. Ultimately, a set of market rules for managing reactive power and voltage support is proposed. The proposal suggests that cost recovery for static and dynamic VARs is appropriately accomplished through the regulated transmission cost of service. Static VAR cost recovery should follow traditional rate recovery methodologies. In the case of dynamic VARs, this work provides a methodology based on the microeconomic theory of the firm for determining such cost. It further suggests that an operational strategy that reduces and limits the use of dynamic VARs, during normal operations, is appropriate. This latter point leads to an increase in the fixed cost of the transmission network but prevents price spikes and short supply situations from affecting, or being affected by, the reactive capability limitations associated with dynamic VARs supplied from synchronous generators. The rules are consistent with a market structure that includes competitive generation and their application will result in the communication of a clear understanding of the responsibilities, related to voltage control, of each type of market entity. In this sense, their application will contribute to

Evaluation of Different Power Saving Techniques for MBMS Services

Directory of Open Access Journals (Sweden)

Antonios Alexiou

2009-01-01

Full Text Available Over the last years we have witnessed an explosive growth of multimedia computing, wireless communication and applications. Following the rapid increase in penetration rate of broadband services, the Third Generation Partnership Project (3GPP is currently standardizing the Evolved-Multimedia Broadcast/Multicast Service (E-MBMS framework of Long Term Evolution (LTE, the successor of Universal Mobile Telecommunications System (UMTS. MBMS constitutes a point-to-multipoint downlink bearer service that was designed to significantly decrease the required radio and wired link resources. However, several obstacles regarding the high-power requirements should be overcome for the realization of MBMS. Techniques, such as Macrodiversity Combining and Rate Splitting, could be utilized to reduce the power requirement of delivering multicast traffic to MBMS users. In this paper, we analytically present several power saving techniques and analyze their performance in terms of power consumption. We provide simulation results that reveal the amount of power that is saved and reinforce the need for the usage of such techniques.

Reactive Power Management in Electric Power Systems

African Journals Online (AJOL)

(Ferranti effect) would limit the power transfer and the transmission range in the absence of any compensation measures. Journal of EAEA, Vol 14, 1997. In this paper, the management of the reactive power is explored with the aim of improving the quality and the reliability of the supply in the EELPA's interconnected system ...

Joint excitation and reactive power control in thermal power plant

Directory of Open Access Journals (Sweden)

Dragosavac Jasna

2013-01-01

Full Text Available The coordinated voltage and reactive power controller, designed for the thermal power plant, is presented in the paper. A brief explanation of the need for such device is given and justification for commissioning of such equipment is outlined. After short description of the theoretical background of the proposed control design, the achieved features of the commissioned equipment are fully given. Achieved performances are illustrated by recorded reactive power and bus voltage responses after commissioning of the described equipment into the largest thermal power plant in Serbia. As it can be seen in presented records, all design targets are met.

REACTIVE POWER DEVICES IN SYSTEMS OF ELECTRIC TRACTION

Directory of Open Access Journals (Sweden)

M. O. Kostin

2010-04-01

Full Text Available A comparative characteristic of different concepts and expressions for determination of reactive power in the circuits with non-sinusoidal electric values has been given. For the first Ukrainian electric locomotives of DE1 type with the system of DC electric traction, the values of reactive power after Budeany, Fryze, and also the differential, integral and generalized reactive powers have been determined. Some measures on reducing its consumption by the DC electric rolling stock have been suggested.

AutoPowerOff plug banks - a story with energy saving perspectives

Energy Technology Data Exchange (ETDEWEB)

Hjort Jensen, Anders (The Danish Electricity Saving Trust (Denmark)); Fjordbak, Troels (IT Energy ApS (Denmark))

2009-07-01

Denmark uses around 35 TWh of electricity per year, with residential dwellings accounting for around 10 TWh of this figure. Standby consumption comprises around 12% of power used in homes. If every Danish home installed AutoPowerOff plug banks, savings exceeding 500 GWh per year would be possible, equivalent to 5% of household electricity consumption, or 1.5% of the total in Denmark. This paper describes the estimated standby consumption in Danish homes in 2006, and possible energy savings through the use of AutoPowerOff plug banks. The estimates were subsequently used as background information for a 2007-2008 campaign to promote the wider use of these devices in Denmark. In order to increase the sale of AutoPowerOff plug banks by 1 million units, it was agreed that retail chains selling consumer electronics would include an AutoPowerOff when selling a TV or PC. A nationwide TV advertising campaign was launched featuring the names of participating retailers. Sales of AutoPowerOff plug banks in the first 7 months of 2008 passed the 515,000 mark, with over 1 million units now installed in 2.5 million Danish households. Annual savings are estimated to be over 80 GWh, equivalent to 40,000 tons of CO{sub 2}. This equates to potential savings on an EU-wide basis of more than 7 TWh, or 3.6 million tons of CO{sub 2} in Denmark.

Relationship between people's awareness of environmental capabilities of saving energy, photovoltaic power generation and nuclear power generation

International Nuclear Information System (INIS)

Hashiba, Takashi

2001-01-01

In this research, relationship between people's awareness of environmental capabilities of saving energy, photovoltaic power generation (PV) and nuclear power generation was investigated using questionnaire method. The results showed that saving energy is conducted without reference to its environment preservation effect. However the older people tend to regard saving energy as contribution to environment preservation. The attitude toward usage of PV has a close relationship to awareness of energy environmental concerns. Acceptance of cost sharing for the introducing of wide-scale PV systems to society is related to environment protection image of PV and the attitude toward loss of social convenience lost as a result of saving energy activities. The older people become, the more priority people put on environment protection before the social convenience. There is little relationship between environmental capabilities of nuclear power generation, that never discharge CO 2 on generation, and awareness of energy environmental concerns. (author)

Simplified reactive power management strategy for complex power grids under stochastic operation and incomplete information

DEFF Research Database (Denmark)

Vlachogiannis, Ioannis (John)

2009-01-01

grids is a major issue for system operators. Under these circumstances an online reactive power management strategy with minimum risk concerning all uncertain and stochastic parameters is proposed. Therefore, new concepts such as reactive power-weighted node-to-node linking and reactive power control......In the current released energy market, the large-scale complex transmission networks and the distribution ones with dispersed energy sources and "intelligent" components operate under uncertainties, stochastic and prior incomplete information. A safe and reliable operation of such complex power...... capability are introduced. A distributed and interconnected stochastic learning automata system is implemented to manage, in a unified and unique way, the reactive power in complex power grids with stochastic reactive power demand and detect the vulnerable part. The proposed simplified strategy can also...

Advanced Reactive Power Reserve Management Scheme to Enhance LVRT Capability

Directory of Open Access Journals (Sweden)

Hwanik Lee

2017-10-01

Full Text Available Abstract: To increase the utilization of wind power in the power system, grid integration standards have been proposed for the stable integration of large-scale wind power plants. In particular, fault-ride-through capability, especially Low-Voltage-Ride-Through (LVRT, has been emphasized, as it is related to tripping in wind farms. Therefore, this paper proposes the Wind power plant applicable-Effective Reactive power Reserve (Wa-ERPR, which combines both wind power plants and conventional generators at the Point of Interconnection (POI. The reactive power capability of the doubly-fed induction generator wind farm was considered to compute the total Wa-ERPR at the POI with reactive power capability of existing generators. By using the Wa-ERPR management algorithm, in case of a violation of the LVRT standards, the amount of reactive power compensation is computed using the Wa-ERPR management scheme. The proposed scheme calculates the Wa-ERPR and computes the required reactive power, reflecting the change of the system topology pre- and post-contingency, to satisfy the LVRT criterion when LVRT regulation is not satisfied at the POI. The static synchronous compensator (STATCOM with the capacity corresponding to calculated amount of reactive power through the Wa-ERPR management scheme is applied to the POI. Therefore, it is confirmed that the wind power plant satisfies the LVRT criteria by securing the appropriate reactive power at the POI, by applying of the proposed algorithm.

An Enhanced Islanding Microgrid Reactive Power, Imbalance Power, and Harmonic Power Sharing Scheme

DEFF Research Database (Denmark)

He, Jinwei; Lin, Yun Wei; Blaabjerg, Frede

2015-01-01

To address inaccurate power sharing problems in autonomous islanding microgrids, an enhanced droop control method through online virtual impedance adjustment is proposed. First, a term associated with DG reactive power, imbalance power, or harmonic power is added to the conventional real power...

Digital reactivity meter

International Nuclear Information System (INIS)

Jiang Zongbing

1996-02-01

The importance and the usual methods of reactivity measurement in a nuclear reactor are presented. Emphasis is put upon the calculation principle, software and hardware components, main specifications, application, as well as the features of the digital reactivity meter. The test results of operation in various reactors shown that the meter possess the following features: high accuracy, short response time, low output noise, high resolution, wide measuring range, simple and flexible to operate, high stability and reliability. In addition, the reactivity meter can save the measuring data automatically and have a perfect capability of self-verifying. It not only meet the requirement of the reactivity measurement in nuclear power plant, but also can be applied to various types of reactors. (1 tab.)

Coordination of baseload power plant group control with static reactive power compensator control

Directory of Open Access Journals (Sweden)

Zbigniew Szczerba

2012-06-01

Full Text Available Reactive power sources in power system nodes: generators and static reactive power compensators, are controlled by control systems. Generators – by generator node group controllers, compensators – by voltage controllers. The paper presents issues of these control systems’ coordination and proposals for its implementation.

Secure provision of reactive power ancillary services in competitive electricity markets

Science.gov (United States)

El-Samahy, Ismael

The research work presented in this thesis discusses various complex issues associated with reactive power management and pricing in the context of new operating paradigms in deregulated power systems, proposing appropriate policy solutions. An integrated two-level framework for reactive power management is set forth, which is both suitable for a competitive market and ensures a secure and reliable operation of the associated power system. The framework is generic in nature and can be adopted for any electricity market structure. The proposed hierarchical reactive power market structure comprises two stages: procurement of reactive power resources on a seasonal basis, and real-time reactive power dispatch. The main objective of the proposed framework is to provide appropriate reactive power support from service providers at least cost, while ensuring a secure operation of the power system. The proposed procurement procedure is based on a two-step optimization model. First, the marginal benefits of reactive power supply from each provider, with respect to system security, are obtained by solving a loadability-maximization problem subject to transmission security constraints imposed by voltage and thermal limits. Second, the selected set of generators is determined by solving an optimal power flow (OPF)-based auction. This auction maximizes a societal advantage function comprising generators' offers and their corresponding marginal benefits with respect to system security, and considering all transmission system constraints. The proposed procedure yields the selected set of generators and zonal price components, which would form the basis for seasonal contracts between the system operator and the selected reactive power service providers. The main objective of the proposed reactive power dispatch model is to minimize the total payment burden on the Independent System Operator (ISO), which is associated with reactive power dispatch. The real power generation is

A new computational method for reactive power market clearing

International Nuclear Information System (INIS)

Zhang, T.; Elkasrawy, A.; Venkatesh, B.

2009-01-01

After deregulation of electricity markets, ancillary services such as reactive power supply are priced separately. However, unlike real power supply, procedures for costing and pricing reactive power supply are still evolving and spot markets for reactive power do not exist as of now. Further, traditional formulations proposed for clearing reactive power markets use a non-linear mixed integer programming formulation that are difficult to solve. This paper proposes a new reactive power supply market clearing scheme. Novelty of this formulation lies in the pricing scheme that rewards transformers for tap shifting while participating in this market. The proposed model is a non-linear mixed integer challenge. A significant portion of the manuscript is devoted towards the development of a new successive mixed integer linear programming (MILP) technique to solve this formulation. The successive MILP method is computationally robust and fast. The IEEE 6-bus and 300-bus systems are used to test the proposed method. These tests serve to demonstrate computational speed and rigor of the proposed method. (author)

Reactive Power Compensating System.

Energy Technology Data Exchange (ETDEWEB)

Williams, Timothy J.; El-Sharkawi, Mohamed A.; Venkata, Subrahmanyam S.

1985-01-04

The circuit was designed for the specific application of wind-driven induction generators. It has great potential for application in any situation where a varying reactive power load is present, such as with induction motors or generators, or for transmission network compensation.

Water reactive hydrogen fuel cell power system

Science.gov (United States)

Wallace, Andrew P; Melack, John M; Lefenfeld, Michael

2014-01-21

A water reactive hydrogen fueled power system includes devices and methods to combine reactant fuel materials and aqueous solutions to generate hydrogen. The generated hydrogen is converted in a fuel cell to provide electricity. The water reactive hydrogen fueled power system includes a fuel cell, a water feed tray, and a fuel cartridge to generate power for portable power electronics. The removable fuel cartridge is encompassed by the water feed tray and fuel cell. The water feed tray is refillable with water by a user. The water is then transferred from the water feed tray into a fuel cartridge to generate hydrogen for the fuel cell which then produces power for the user.

Simplified reactive power management strategy for complex power grids under stochastic operation and incomplete information

International Nuclear Information System (INIS)

Vlachogiannis, John G.

2009-01-01

In the current released energy market, the large-scale complex transmission networks and the distribution ones with dispersed energy sources and 'intelligent' components operate under uncertainties, stochastic and prior incomplete information. A safe and reliable operation of such complex power grids is a major issue for system operators. Under these circumstances an online reactive power management strategy with minimum risk concerning all uncertain and stochastic parameters is proposed. Therefore, new concepts such as reactive power-weighted node-to-node linking and reactive power control capability are introduced. A distributed and interconnected stochastic learning automata system is implemented to manage, in a unified and unique way, the reactive power in complex power grids with stochastic reactive power demand and detect the vulnerable part. The proposed simplified strategy can also consider more stochastic aspects such as variable grid's topology. Results of the proposed strategy obtained on the networks of IEEE 30-bus and IEEE 118-bus systems demonstrate the effectiveness of the proposed strategy.

Power and reactive power simultaneous control by 0.5 MJ superconducting magnet energy storage

International Nuclear Information System (INIS)

Ise, Toshifumi; Tsuji, Kiichiro; Murakami, Yoshishige

1984-01-01

Superconducting magnet energy storage (SMES) is expected to be widely applied to the pulsed sources for fusion reactor research and to the energy storage substituting for pumping-up power stations, because of its fast energy storing and discharging and very high efficiency. Some results have been obtained so far. In this paper, however, the simultaneous control of power and reactive power is considered for an energy storage composed of two sets of thyristorized power conversion system and superconducting magnets in series connection, and a direct digital control system is described on the principle, design and configuration including the compensator, and on the experiment using the 0.5 MJ superconducting magnet energy storage installed in the Superconduction Engineering Experiment Center, Osaka University. The results obtained are as follows: (1) P control priority mode and Q control priority mode (in which power and reactive power control has priority, respectively) were proposed as the countermeasures when the simultaneous control of power and reactive power became impossible; (2) the design method was established, by which power and reactive power control loops can independently be designed as a result of simulation; (3) the achievement of the simultaneous control of power and reactive power was confirmed by using P-control priority mode and Q-control priority mode, in the experiment using the control system designed by simulation. The validity of simulation model was also confirmed by actual response waveforms. (Wakatsuki, Y.)

Energy-saving decomposition and power consumption forecast: The case of liaoning province in China

Energy Technology Data Exchange (ETDEWEB)

He, Y.X.; Zhao, Y.S.; Wang, Y.J. [School of Business Administration, North China Electric Power University, Zhu Xin Zhuang, Bei Nong Lu No. 2, Changping District, Beijing (China); Zhang, S.L. [Finance Department, Nanning Power Supply Bureau, Xingguang Street No. 43, Nanning, Guangxi Autonomous Region (China); Li, F.R. [University of Bath, Bath, BA2 7AY (United Kingdom)

2011-01-15

To achieve sustainable development of the society, the People's Republic of China (PRC) proposed in its 11th Five-Year Plan for National Economic and Social Development Program a shift in energy-saving target of decreasing energy intensity by 20% in 2010 compared with that of 2005. Liaoning province is one of the oldest industrial bases in China. Policymakers are often confronted with problems relating to adjustment in the development pattern as a means to secure steady economic growth. The power industry is a fundamental energy industry; it plays an important role in realizing of energy-saving targets. Based on the input-output model, this paper sets extensive, planning and 20% energy-saving scenarios in order to analyze energy-saving and power consumption situations for Liaoning by 2010. Through extensive simulations, the levels of energy-saving and power demand under different scenarios are obtained. Results from the analysis show that under the premises of adjusting the ratio of investment and consumption, optimizing products structure, and improving energy use efficiency, it is possible to achieve the proposed energy-saving target. Liaoning's power consumption can maintain a stable growth trend in the future. The percentage of electricity to the total energy use can also increase to 16% in 2010. (author)

An accurate autonomous islanding microgrid reactive power, imbalance power and harmonic power sharing scheme

DEFF Research Database (Denmark)

He, Jinwei; Li, Yun Wei; Blaabjerg, Frede

2013-01-01

To address inaccurate power sharing problems in autonomous islanding microgrids, an enhanced droop control method through adaptive virtual impedance adjustment is proposed. First, a term associated with DG reactive power, imbalance power or harmonic power is added to the conventional real power...

An accurate reactive power control study in virtual flux droop control

Science.gov (United States)

Wang, Aimeng; Zhang, Jia

2017-12-01

This paper investigates the problem of reactive power sharing based on virtual flux droop method. Firstly, flux droop control method is derived, where complicated multiple feedback loops and parameter regulation are avoided. Then, the reasons for inaccurate reactive power sharing are theoretically analyzed. Further, a novel reactive power control scheme is proposed which consists of three parts: compensation control, voltage recovery control and flux droop control. Finally, the proposed reactive power control strategy is verified in a simplified microgrid model with two parallel DGs. The simulation results show that the proposed control scheme can achieve accurate reactive power sharing and zero deviation of voltage. Meanwhile, it has some advantages of simple control and excellent dynamic and static performance.

Formation for the calculation of reactivity without nuclear power history

International Nuclear Information System (INIS)

Suescun Diaz, Daniel; Senra Martinez, Aquilino; Carvalho Da Silva, Fernando

2007-01-01

This paper presents a new method for the solution of the inverse point kinetics equation. This method is based on the integration by parts of the integral of the inverse point kinetics equation, which results in a power series in terms of the nuclear power in time dependence. With the imposition of conditions to the nuclear power, the reactivity is represented as first and second derivatives of this nuclear power. This new calculation method for reactivity has very special characteristics, amongst which the possibility of using longer sampling period, and the possibility of restarting the calculation, after its interruption, allowing the calculation of reactivity in a non-continuous way. Beside that, the reactivity can be obtained independent of the nuclear power memory. (author)

Stochastic reactive power market with volatility of wind power considering voltage security

International Nuclear Information System (INIS)

Kargarian, A.; Raoofat, M.

2011-01-01

While wind power generation is growing rapidly around the globe; its stochastic nature affects the system operation in many different aspects. In this paper, the impact of wind power volatility on the reactive power market is taken into account. The paper presents a novel stochastic method for optimal reactive power market clearing considering voltage security and volatile nature of the wind. The proposed optimization algorithm uses a multiobjective nonlinear programming technique to minimize market payment and simultaneously maximize voltage security margin. Considering a set of probable wind speeds, in the first stage, the proposed algorithm seeks to minimize expected system payment which is summation of reactive power payment and transmission loss cost. The object of the second stage is maximization of expected voltage security margin to increase the system loadability and security. Finally, in the last stage, a multiobjective function is presented to schedule the stochastic reactive power market using results of two previous stages. The proposed algorithm is applied to IEEE 14-bus test system. As a benchmark, Monte Carlo Simulation method is utilized to simulate the actual market of given period of time to evaluate results of the proposed algorithm, and satisfactory results are achieved. -- Highlights: →The paper proposes a new algorithm for stochastic reactive power market clearing. →The stochastic nature of the wind which impacts the system operation and market clearing process, is taken into account. →The paper suggests an expected voltage stability margin and optimizes it in conjunction with expected total market payment. →To clear the market with two mentioned objective functions, a three-stage multiobjective nonlinear programming is implemented. →Also, a simple method is suggested to determine a suitable priority coefficient between two individual objective functions.

Reactive power control methods for improved reliability of wind power inverters under wind speed variations

DEFF Research Database (Denmark)

Ma, Ke; Liserre, Marco; Blaabjerg, Frede

2012-01-01

method to relieve the thermal cycling of power switching devices under severe wind speed variations, by circulating reactive power among the parallel power converters in a WTS or among the WTS's in a wind park. The amount of reactive power is adjusted to limit the junction temperature fluctuation...

Relationship between people's awareness of environmental capabilities of saving energy, photovoltaic power generation and nuclear power generation

Energy Technology Data Exchange (ETDEWEB)

Hashiba, Takashi [Institute of Nuclear Safety System Inc., Mihama, Fukui (Japan)

2001-09-01

In this research, relationship between people's awareness of environmental capabilities of saving energy, photovoltaic power generation (PV) and nuclear power generation was investigated using questionnaire method. The results showed that saving energy is conducted without reference to its environment preservation effect. However the older people tend to regard saving energy as contribution to environment preservation. The attitude toward usage of PV has a close relationship to awareness of energy environmental concerns. Acceptance of cost sharing for the introducing of wide-scale PV systems to society is related to environment protection image of PV and the attitude toward loss of social convenience lost as a result of saving energy activities. The older people become, the more priority people put on environment protection before the social convenience. There is little relationship between environmental capabilities of nuclear power generation, that never discharge CO{sub 2} on generation, and awareness of energy environmental concerns. (author)

Agent-based reactive power management of power distribution networks with distributed energy generation

International Nuclear Information System (INIS)

Rahman, M.S.; Mahmud, M.A.; Oo, A.M.T.; Pota, H.R.; Hossain, M.J.

2016-01-01

Highlights: • A coordinated multi-agent system is proposed for reactive power management. • A linear quadratic regulator with a proportional integral controller is designed. • Proposed multi-agent scheme provides accurate estimation and control of the system. • Voltage stability is improved with proper power management for different scenarios. • Results obtained from the proposed scheme is compared to the traditional approach. - Abstract: In this paper, a new agent-based distributed reactive power management scheme is proposed to improve the voltage stability of energy distribution systems with distributed generation units. Three types of agents – distribution system agent, estimator agent, and control agent are developed within the multi-agent framework. The agents simultaneously coordinated their activities through the online information and energy flow. The overall achievement of the proposed scheme depends on the coordination between two tasks – (i) estimation of reactive power using voltage variation formula and (ii) necessary control actions to provide the estimated reactive power to the distribution networks through the distributed static synchronous compensators. A linear quadratic regulator with a proportional integrator is designed for the control agent in order to control the reactive component of the current and the DC voltage of the compensators. The performance of the proposed scheme is tested on a 10-bus power distribution network under various scenarios. The effectiveness is validated by comparing the proposed approach to the conventional proportional integral control approach. It is found that, the agent-based scheme provides excellent robust performance under various operating conditions of the power distribution network.

The Large Customer Reactive Power Control Possibilities

Directory of Open Access Journals (Sweden)

Robert Małkowski

2014-03-01

Full Text Available In this paper the authors wish to draw attention to the rationale for, and the possibility of, the use of local reactive power sources by the Transmission Node Master Controller (TNMC. Large Customers (LC are one of the possible reactive power sources. The paper presents the issues related to the need for coordination between the control systems installed in the LC network, and coordination between control systems of the LC as well as master control systems in the network.

Ant colony search algorithm for optimal reactive power optimization

Directory of Open Access Journals (Sweden)

Lenin K.

2006-01-01

Full Text Available The paper presents an (ACSA Ant colony search Algorithm for Optimal Reactive Power Optimization and voltage control of power systems. ACSA is a new co-operative agents’ approach, which is inspired by the observation of the behavior of real ant colonies on the topic of ant trial formation and foraging methods. Hence, in the ACSA a set of co-operative agents called "Ants" co-operates to find good solution for Reactive Power Optimization problem. The ACSA is applied for optimal reactive power optimization is evaluated on standard IEEE, 30, 57, 191 (practical test bus system. The proposed approach is tested and compared to genetic algorithm (GA, Adaptive Genetic Algorithm (AGA.

Ancillary reactive power service allocation cost in deregulated markets: a methodology

International Nuclear Information System (INIS)

Hernandez, J. Horacio Tovar; Jimenez-Guzman, Miguel; Gutierrez-Alcaraz, Guillermo

2005-01-01

This paper presents a methodology to allocate reactive power costs in deregulated markets. Reactive power supply service is decomposed into voltage regulation and reactive power spinning reserve. The proposed methodology is based on sensitivities and the postage-stamp method in order to allocate the total costs service among all participants. With the purpose of achieving this goal, the system operator identifies voltage support and/or reactive power requirements, and looks out for suitable providers. One case study is presented here to illustrate the methodology over a simplified southeastern Mexican grid. (Author)

Framework for the analysis of reactive power dispatch in energy pools

International Nuclear Information System (INIS)

Salgado, R.S.; Irving, M.R.

2004-01-01

This paper proposes a framework for the simulation and analysis of the reactive power distribution in electric energy markets of the pool type. Firstly, the analytical formulation of the OPF problem, with three optional performance indexes for the reactive power dispatch, is discussed. These OPF objectives are used to determine the reactive power distribution for a given active power dispatch (obtained through merit-order strategy, for instance). An allocation strategy is used to assess the participation of each power system agent in the loss/reactive power distribution. This strategy uses the premise of co-operative game theory. Numerical results obtained with the Ward-Hale 6-bus test system illustrate the main aspects of the proposed methodology. (author)

Reactive power compensating system

Energy Technology Data Exchange (ETDEWEB)

Williams, Timothy J. (Redondo Beach, CA); El-Sharkawi, Mohamed A. (Renton, WA); Venkata, Subrahmanyam S. (Seattle, WA)

1987-01-01

The reactive power of an induction machine is compensated by providing fixed capacitors on each phase line for the minimum compensation required, sensing the current on one line at the time its voltage crosses zero to determine the actual compensation required for each phase, and selecting switched capacitors on each line to provide the balance of the compensation required.

In-core power sharing and fuel requirement study for a decommissioning Boiling Water Reactor using the linear reactivity model

International Nuclear Information System (INIS)

Chen, Chung-Yuan; Tung, Wu-Hsiung; Yaur, Shung-Jung; Kuo, Weng-Sheng

2014-01-01

Highlights: • Linear reactivity model (LRM) was modified and applied to Boiling Water Reactor. • The power sharing and fuel requirement study of the last cycle and two cycles before decommissioning was implemented. • The loading pattern design concept for the cycles before decommissioning is carried out. - Abstract: A study of in-core power sharing and fuel requirement for a decommissioning BWR (Boiling Water Reactor) was carried out using the linear reactivity model (LRM). The power sharing of each fuel batch was taken as an independent variable, and the related parameters were set and modified to simulate actual cases. Optimizations of the last cycle and two cycles before decommissioning were both implemented; in the last-one-cycle optimization, a single cycle optimization was carried out with different upper limits of fuel batch power, whereas, in the two-cycle optimization, two cycles were optimized with different cycle lengths, along with two different optimization approaches which are the simultaneous optimization of two cycles (MO) and two successive single-cycle optimizations (SO). The results of the last-one-cycle optimization show that it is better to increase the fresh fuel power and decrease the thrice-burnt fuel power as much as possible. It also shows that relaxing the power limit is good to the fresh fuel requirement which will be reduced under lower power limit. On the other hand, the results of the last-two-cycle (cycle N-1 and N) optimization show that the MO is better than SO, and the power of fresh fuel batch should be decreased in cycle N-1 to save its energy for the next cycle. The results of the single-cycle optimization are found to be the same as that in cycle N of the multi-cycle optimization. Besides that, under the same total energy requirement of two cycles, a long-short distribution of cycle length design can save more fresh fuel

Optimized Reactive Power Flow of DFIG Power Converters for Better Reliability Performance Considering Grid Codes

DEFF Research Database (Denmark)

Zhou, Dao; Blaabjerg, Frede; Lau, Mogens

2015-01-01

. In order to fulfill the modern grid codes, over-excited reactive power injection will further reduce the lifetime of the rotor-side converter. In this paper, the additional stress of the power semiconductor due to the reactive power injection is firstly evaluated in terms of modulation index...

EVALUATING DEGREE OF ACTIVE POWER LOSSES REDUCTION IN THE ELECTRIC POWER LINES WITH REACTIVE POWER COMPENSATION

Directory of Open Access Journals (Sweden)

V. N. Radkevich

2016-01-01

Full Text Available The paper considers evaluation procedure for the degree of active power losses reduction in the power transmission lines under 1 kV and 6–10 kV of the systems of electric power supply of industrial enterprises with compensating installations mounted at the side of the customer. The capacitor installations conform to the applied voltage level and factor in dielectric losses in the capacitors. The voltage at the compensating device terminal changes from 0.95 to 1.05 of the capacitors nominal voltage. The study did not account for reactive power losses in the line, nor did it for its charge capacity, conditioned by relative shortness of the cable lines generally operating in the mains of industrial enterprises. For this reason, the quantities of reactive power being consumed and generated by the transmission line are negligible and do not significantly affect the reactive power flux. The researchers obtain functional relations that allow estimating the degree of power loss reduction in the transmission line factoring in its explicit initial data. They perform mathematical analysis of the obtained functional relations and study the function by means of derivatives. The function extremum points are found as well as the intervals of its increment and decrement. A graphical research of the obtained functional relation is performed. It is ascertained that reduction of the active power losses is contingent on the line and the capacitor-installation engineering factors, the electrical energy consumer reactive load value as well as the voltage applied to the capacitor installation. The functional relations presented in the article can be employed in scoping calculation necessary for decision making on the reactive power compensation in systems of the industrial facilities electric power supply. Their account will allow a more accurate estimate of technical and economic effect of the capacitor bank installation in the electrical mains under 1 kV and 6�

Power and power-to-flow reactivity transfer functions in EBR-II [Experimental Breeder Reactor II] fuel

International Nuclear Information System (INIS)

Grimm, K.N.; Meneghetti, D.

1989-01-01

Reactivity transfer functions are important in determining the reactivity history during a power transient. Overall nodal transfer functions have been calculated for different subassembly types in the Experimental Breeder Reactor II (EBR-II). Steady-state calculations for temperature changes and, hence, reactivities for power changes have been separated into power and power-to-flow-dependent terms. Axial nodal transfer functions separated into power and power-to-flow-dependent components are reported in this paper for a typical EBR-II fuel pin. This provides an improved understanding of the time dependence of these components in transient situations

Modelling of power-reactivity coefficient measurement

International Nuclear Information System (INIS)

Strmensky, C.; Petenyi, V.; Jagrik, J.; Minarcin, M.; Hascik, R.; Toth, L.

2005-01-01

Report describes results of modeling of power-reactivity coefficient analysis on power-level. In paper we calculate values of discrepancies arisen during transient process. These discrepancies can be arisen as result of experiment evaluation and can be caused by disregard of 3D effects on neutron distribution. The results are critically discussed (Authors)

Identification of fast power reactivity effect in nuclear power reactor

International Nuclear Information System (INIS)

Efanov, A.I.; Kaminskas, V.A.; Lavrukhin, V.S.; Rimidis, A.P.; Yanitskene, D.Yu.

1987-01-01

A nuclear power reactor is an object of control with distributed parameters, characteristics of which vary during operation time. At the same time the reactor as the object of control has internal feedback circuits, which are formed as a result of the effects of fuel parameters and a coolant (pressure, temperature, steam content) on the reactor breeding properties. The problem of internal feedback circuit identification in a nuclear power reactor is considered. Conditions for a point reactor identification are obtained and algorithms of parametric identification are constructed. Examples of identification of fast power reactivity effect for the RBMK-1000 reactor are given. Results of experimental testing have shown that the developed method of fast power reactivity effect identification permits according to the data of normal operation to construct adaptive models for the point nuclear reactor, designed for its behaviour prediction in stationary and transition operational conditions. Therefore, the models considered can be used for creating control systems of nuclear power reactor thermal capacity (of RBMK type reactor, in particular) which can be adapted to the change in the internal feedback circuit characteristics

Study for reactive power on distribution system line B RSG-GAS

International Nuclear Information System (INIS)

Yan Bony Marsahala

2010-01-01

Study for reactive power on distribution system line B RSG-GA is already done. The study intended to evaluate how much inductive load need the reactive power (positive), how much power factor, and what will be done to increase the power factor. The reactive power is the losses power, can't be changed into energy, but it is need for transmission process and it is cause the energy losses. The loads on distribution system line B consist of induction motors which are used for primary cooling system and secondary cooling system, lift, blower on cooling tower, and air condition system. Due to the motors using, the power factor are falling down to low. By the calculation results give that the inductive loads on distribution line B are 850 KVA and these loads caused the low power factor 0.80. If we want to increase the power factor up to 0.95, it is need to install the reactive loads likes capacitor bank 250 KVAR. (author)

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)

Modelling and automatic reactive power control of isolated wind-diesel hybrid power systems using ANN

International Nuclear Information System (INIS)

Bansal, R.C.

2008-01-01

This paper presents an artificial neural network (ANN) based approach to tune the parameters of the static var compensator (SVC) reactive power controller over a wide range of typical load model parameters. The gains of PI (proportional integral) based SVC are optimised for typical values of the load voltage characteristics (n q ) by conventional techniques. Using the generated data, the method of multi-layer feed forward ANN with error back propagation training is employed to tune the parameters of the SVC. An ANN tuned SVC controller has been applied to control the reactive power of a variable slip/speed isolated wind-diesel hybrid power system. It is observed that the maximum deviations of all parameters are more for larger values of n q . It has been shown that initially synchronous generator supplies the reactive power required by the induction generator and/or load, and the latter reactive power is purely supplied by the SVC

Modelling and automatic reactive power control of isolated wind-diesel hybrid power systems using ANN

Energy Technology Data Exchange (ETDEWEB)

Bansal, R.C. [Electrical and Electronics Engineering Division, School of Engineering and Physics, The University of the South Pacific, Suva (Fiji)

2008-02-15

This paper presents an artificial neural network (ANN) based approach to tune the parameters of the static var compensator (SVC) reactive power controller over a wide range of typical load model parameters. The gains of PI (proportional integral) based SVC are optimised for typical values of the load voltage characteristics (n{sub q}) by conventional techniques. Using the generated data, the method of multi-layer feed forward ANN with error back propagation training is employed to tune the parameters of the SVC. An ANN tuned SVC controller has been applied to control the reactive power of a variable slip/speed isolated wind-diesel hybrid power system. It is observed that the maximum deviations of all parameters are more for larger values of n{sub q}. It has been shown that initially synchronous generator supplies the reactive power required by the induction generator and/or load, and the latter reactive power is purely supplied by the SVC. (author)

Reactive Power Impact on Lifetime Prediction of Two-level Wind Power Converter

DEFF Research Database (Denmark)

Zhou, Dao; Blaabjerg, Frede; Lau, M.

2013-01-01

The influence of reactive power injection on the dominating two-level wind power converter is investigated and compared in terms of power loss and thermal behavior. Then the lifetime of both the partial-scale and full-scale power converter is estimated based on the widely used Coffin-Manson model...

Real-Time Reactive Power Distribution in Microgrids by Dynamic Programing

DEFF Research Database (Denmark)

Levron, Yoash; Beck, Yuval; Katzir, Liran

2017-01-01

In this paper a new real-time optimization method for reactive power distribution in microgrids is proposed. The method enables location of a globally optimal distribution of reactive power under normal operating conditions. The method exploits the typical compact structure of microgrids to obtain...... combination of reactive powers, by means of dynamic programming. Since every single step involves a one-dimensional problem, the complexity of the solution is only linear with the number of clusters, and as a result, a globally optimal solution may be obtained in real time. The paper includes the results...

A heuristic technique to determine corrective control actions for reactive power flows

Energy Technology Data Exchange (ETDEWEB)

Trigo, Angel L.; Martinez, Jose L.; Riquelme, Jesus; Romero, Esther [Department of Electrical Engineering, University of Sevilla (Spain)

2011-01-15

This paper presents a sensitivity-based heuristic tool designed to help the system operator in the reactive power flow control problem. The objective of the proposed technique is to determine control actions to ensure that reactive power flows in transmission-subtransmission boundary transformers remain within specified limits, satisfying the new regulatory constraints imposed in most of deregulated markets. With this new constraint the utilities want to guarantee that the utility is able to satisfy its own reactive power requirements, avoiding reactive power flows through long distances in order to reduce the well known disadvantages that reactive power circulation has in the system. A 5-bus tutorial system is used to present the proposed algorithm. The results of the application of the proposed technique to the IEEE 118 buses system and to a regional subtransmission network of the South of Spain are reported and analyzed. In this last actual case, the aim is to maintain reactive power flows in transmission/distribution transformers between those limits set by the Spanish Regulation. A comparison between the proposed tool and a conventional OPF is discussed. (author)

Novel power saving architecture for FBG based OCDMA code generation

Science.gov (United States)

Osadola, Tolulope B.; Idris, Siti K.; Glesk, Ivan

2013-10-01

A novel architecture for generating incoherent, 2-dimensional wavelength hopping-time spreading optical CDMA codes is presented. The architecture is designed to facilitate the reuse of optical source signal that is unused after an OCDMA code has been generated using fiber Bragg grating based encoders. Effective utilization of available optical power is therefore achieved by cascading several OCDMA encoders thereby enabling 3dB savings in optical power.

Distribution factors for reactive power in the presence of bilateral transactions

International Nuclear Information System (INIS)

De Tuglie, E.; Torelli, F.

2004-01-01

The twin factors of limited investment in electric transmission systems and the overexploitation of electrical resources results in an increase in the need for reactive power to support system voltage profile and to supply loads. It is reasonable to expect that generators and compensators, heavily involved in reactive support on a voluntary basis, will be remunerated for their service by market transactions. This remuneration will depend on the network topology, i.e. of buyers, sellers and reactive injection locations, on the active power exchanged and the reactive power required by loads. All these aspects are taken into account in developing a methodology based on circuit considerations. Using this approach, at a given system operating point characterised by a predefined set of transactions, reactive responsibilities can be formulated as the sum of two terms: one strictly related to transactions and the other dependent on electric network parameters. Test results demonstrate the efficacy of the proposed methodology in sharing reactive power responsibilities in a fair way among market participants. (author)

Broadband and High power Reactive Jamming Resilient Wireless Communication

Science.gov (United States)

2017-10-21

Broadband and High -power Reactive Jamming Resilient Wireless Communication The views, opinions and/or findings contained in this report are those of... available in extremely hostile environments, where FHSS and DSSS are completely defeated by a broadband and high -power reactive jammer. b. Wireless...SECURITY CLASSIFICATION OF: 1. REPORT DATE (DD-MM-YYYY) 4. TITLE AND SUBTITLE 13. SUPPLEMENTARY NOTES 12. DISTRIBUTION AVAILIBILITY STATEMENT 6. AUTHORS

Photovoltaic solar system connected to the electric power grid operating as active power generator and reactive power compensator

Energy Technology Data Exchange (ETDEWEB)

Albuquerque, F.L.; Moraes, A.J.; Guimaraes, G.C.; Sanhueza, S.M.R.; Vaz, A.R. [Federal University of Uberlandia (UFU), MG (Brazil)

2009-07-01

In the case of photovoltaic solar systems (PV) acting as a distributed generation (DG), the DC energy obtained is fed through the power-conditioning unit (inverter) to the grid. The majority of contemporary inverters used in DG systems are current source inverters (CSI) operating at unity power factor. If, however, we assume that voltage source inverters (VSI) can be utilized instead of CSI, we can generate reactive power commensurate with the remaining unused capacity at any given point in time. According to the theory of instantaneous power, the reactive and active power of inverter can be regulated by changing the amplitude and the phase of the output voltage of the inverter. Based on this theory, the active power output and the reactive power compensation (RPC) of the system are realized simultaneously. When the insolation is weak or the PV modules are inoperative at night, the RPC feature of PV system can still be used to improve the utilization factor of the inverter. The MATLAB simulation results validate the feasibility of the method. (author)

Vattenfall want to save money: will run Ringhals 3 and 4 with reduced power

International Nuclear Information System (INIS)

Anon.

1982-01-01

Ringhals 3 and 4 are nuclear power stations which require re-design before full power can be generated. To save money both stations will be running at reduced power during 1982 to generate power and gain running experience. (J.H.)

Active and reactive power neurocontroller for grid-connected photovoltaic generation system

Directory of Open Access Journals (Sweden)

I. Abadlia

2016-03-01

Full Text Available Many researchers have contributed to the development of a firm foundation for analysis and design of control applications in grid-connected renewable energy sources. This paper presents an intelligent control algorithm fond on artificial neural networks for active and reactive power controller in grid-connected photovoltaic generation system. The system is devices into two parts in which each part contains an inverter with control algorithm. A DC/DC converter in output voltage established by control magnitude besides maximum power point tracker algorithm always finds optimal power of the PV array in use. A DC/AC hysteresis inverter designed can synchronize a sinusoidal current output with the grid voltage and accurate an independent active and reactive power control. Simulation results confirm the validation of the purpose. Neurocontroller based active and reactive power presents an efficiency control that guarantees good response to the steps changing in active and reactive power with an acceptable current/voltage synchronism. In this paper the power circuit and the control system of the presented grid-connected photovoltaic generation system is simulated and tested by MatLab/Simulink.

Estimation of reactive power sources dynamic limits for Volt / VAr control

International Nuclear Information System (INIS)

Orozco Alvarado, Juan Jose

2013-01-01

A generic model of capacity curves is obtained from the theoretical capacity curves of the distribution generators and reactive compensation elements. The obtained generic model is structured in a simplified method of points, taking eight strategic points of two detailed curves of a generator and through a series of interpolations, achieving the estimation of limits of capacity of delivery / consumption of the generator. The theory of electric generation elements and reactive power compensation is reviewed. The curves of capacity 'Reactive Power / Active Power' are achieved for different values of tension: from wind generators with complete converter and doubly fed, photovoltaic generators with inverter and synchronous generators. The 'Reactive Power / Line Tension' capacity curves are acquired from static var compensators (SVC). The generic limits of generators and SVC are estimated from the capacity curves [es

Improvement of the dynamic response of the ITER Reactive Power Compensation system

International Nuclear Information System (INIS)

Finotti, Claudio; Gaio, Elena; Song, Inho; Tao, Jun; Benfatto, Ivone

2015-01-01

Highlights: • The slow response reasons of the classic ITER Reactive Power Compensation (RPC) control are explained. • The dynamic behaviors of the ac/dc converter and of the RPC are characterized. • New control concept to speed up the RPC response is developed. • Good performance of the new RPC control is verified even during fast transient conditions. - Abstract: The ITER ac/dc conversion system can absorb a total active and reactive power up to 500 MW and 950 Mvar, respectively. The Reactive Power Compensation (RPC) system is rated for a nominal power of 750 Mvar necessary to comply with the allowable reactive power limit value from the grid of 200 Mvar. This system is currently under construction and is based on Static Var Compensation technology with Thyristor Controlled Reactor (TCR) and Tuned Filters. The RPC has to minimize the demand of reactive power from the grid; its control is based on a feed-forward method, where the corrective input is the measurement of the reactive power consumption of the ac/dc converters, derived from the 50 Hz component of the Fast Fourier Transform (FFT) of the three-phase voltages and currents. The delay introduced by the FFT calculation and the slow response of the TCR could make the response speed of the RPC not sufficient to face fast variations of the reactive power demand and therefore in this paper a new controller of the RPC able to overcome this shortcoming is proposed and evaluated. It is based on the calculation of the predicted consumption of the reactive power by using the voltage reference signals coming from the Plasma Control System and the measurements of the dc current of the ac/dc converters and of the 66 kV busbar voltage, and on the speed up of the RPC control by introducing a lead–lag transfer function.

Improvement of the dynamic response of the ITER Reactive Power Compensation system

Energy Technology Data Exchange (ETDEWEB)

Finotti, Claudio, E-mail: claudio.finotti@igi.cnr.it [Consorzio RFX (CNR, ENEA, INFN, Università di Padova, Acciaierie Venete SpA), Corso Stati Uniti 4, 35127 Padova (Italy); Gaio, Elena [Consorzio RFX (CNR, ENEA, INFN, Università di Padova, Acciaierie Venete SpA), Corso Stati Uniti 4, 35127 Padova (Italy); Song, Inho; Tao, Jun; Benfatto, Ivone [ITER Organization, Route de Vinon-sur-Verdon, CS 90 046, 13067 St. Paul Lez Durance Cedex (France)

2015-10-15

Highlights: • The slow response reasons of the classic ITER Reactive Power Compensation (RPC) control are explained. • The dynamic behaviors of the ac/dc converter and of the RPC are characterized. • New control concept to speed up the RPC response is developed. • Good performance of the new RPC control is verified even during fast transient conditions. - Abstract: The ITER ac/dc conversion system can absorb a total active and reactive power up to 500 MW and 950 Mvar, respectively. The Reactive Power Compensation (RPC) system is rated for a nominal power of 750 Mvar necessary to comply with the allowable reactive power limit value from the grid of 200 Mvar. This system is currently under construction and is based on Static Var Compensation technology with Thyristor Controlled Reactor (TCR) and Tuned Filters. The RPC has to minimize the demand of reactive power from the grid; its control is based on a feed-forward method, where the corrective input is the measurement of the reactive power consumption of the ac/dc converters, derived from the 50 Hz component of the Fast Fourier Transform (FFT) of the three-phase voltages and currents. The delay introduced by the FFT calculation and the slow response of the TCR could make the response speed of the RPC not sufficient to face fast variations of the reactive power demand and therefore in this paper a new controller of the RPC able to overcome this shortcoming is proposed and evaluated. It is based on the calculation of the predicted consumption of the reactive power by using the voltage reference signals coming from the Plasma Control System and the measurements of the dc current of the ac/dc converters and of the 66 kV busbar voltage, and on the speed up of the RPC control by introducing a lead–lag transfer function.

Advanced configuration of hybrid passive filter for reactive power and harmonic compensation.

Science.gov (United States)

Kececioglu, O Fatih; Acikgoz, Hakan; Sekkeli, Mustafa

2016-01-01

Harmonics is one of the major power quality problems for power systems. The harmonics can be eliminated by power filters such as passive, active, and hybrid. In this study, a new passive filter configuration has been improved in addition to the existing passive filter configurations. Conventional hybrid passive filters are not successful to compensate rapidly changing reactive power demand. The proposed configure are capable of compensating both harmonics and reactive power at the same time. Simulation results show that performance of reactive power and harmonic compensation with advanced hybrid passive filter is better than conventional hybrid passive filters.

Dynamic Performance of the ITER Reactive Power Compensation System

International Nuclear Information System (INIS)

Sheng Zhicai; Fu Peng; Xu Liuwei

2011-01-01

Dynamic performance of a reactive power compensation (RPC) system for the international thermonuclear experimental reactor (ITER) power supply is presented. Static var compensators (SVCs) are adopted to mitigate voltage fluctuation and reduce the reactive power down to a level acceptable for the French/European 400 kV grid. A voltage feedback and load power feedforward controller for SVC is proposed, with the feedforward loop intended to guarantee short response time and the feedback loop ensuring good dynamics and steady characteristics of SVC. A mean filter was chosen to measure the control signals to improve the dynamic response. The dynamic performance of the SVC is verified by simulations using PSCAD/EMTDC codes.

Multi-objective Reactive Power Optimization Based on Improved Particle Swarm Algorithm

Science.gov (United States)

Cui, Xue; Gao, Jian; Feng, Yunbin; Zou, Chenlu; Liu, Huanlei

2018-01-01

In this paper, an optimization model with the minimum active power loss and minimum voltage deviation of node and maximum static voltage stability margin as the optimization objective is proposed for the reactive power optimization problems. By defining the index value of reactive power compensation, the optimal reactive power compensation node was selected. The particle swarm optimization algorithm was improved, and the selection pool of global optimal and the global optimal of probability (p-gbest) were introduced. A set of Pareto optimal solution sets is obtained by this algorithm. And by calculating the fuzzy membership value of the pareto optimal solution sets, individuals with the smallest fuzzy membership value were selected as the final optimization results. The above improved algorithm is used to optimize the reactive power of IEEE14 standard node system. Through the comparison and analysis of the results, it has been proven that the optimization effect of this algorithm was very good.

A DFIG Islanding Detection Scheme Based on Reactive Power Infusion

Science.gov (United States)

Wang, M.; Liu, C.; He, G. Q.; Li, G. H.; Feng, K. H.; Sun, W. W.

2017-07-01

A lot of research has been done on photovoltaic (the “PV”) power system islanding detection in recent years. As a comparison, much less attention has been paid to islanding in wind turbines. Meanwhile, wind turbines can work in islanding conditions for quite a long period, which can be harmful to equipments and cause safety hazards. This paper presents and examines a double fed introduction generation (the “DFIG”) islanding detection scheme based on feedback of reactive power and frequency and uses a trigger signal of reactive power infusion which can be obtained by dividing the voltage total harmonic distortion (the "THD") by the voltage THD of last cycle to avoid the deterioration of power quality. This DFIG islanding detection scheme uses feedback of reactive power current loop to amplify the frequency differences in islanding and normal conditions. Simulation results show that the DFIG islanding detection scheme is effective.

Saving assessment using the PERS in solar power towers

International Nuclear Information System (INIS)

Rodriguez-Sanchez, M.R.; Sanchez-Gonzalez, A.; Marugan-Cruz, C.; Santana, D.

2014-01-01

Highlights: • The lamination of the solar salt is avoided using the PERS and the main energy sink. • The PERS using salt pump as turbine saves 30–50% of the parasitic power. • The most appropriate configuration is a similar turbine three times one salt pump. • The payback period is around two years, and the economical savings from 1 to 4 M$. - Abstract: The improvement of the solar power tower using solar salt is one of the main goals of researchers. Any method or invention to improve the efficiency of this technology contributes to promote the renewable energies. The use of a Potential Energy Recovery System (PERS) in two different solar power tower plants of 20 and 100 MW has been analysed. The PERS is formed, at least, by one turbine, located at the hot salt pipe coming from the receiver. The turbine is engaged to the shaft of the feed pump, which raises the heat transfer fluid from the cold tank to the receiver. It reduces the parasitic power consumption of the plant, and increases its global efficiency. Different PERS configurations have been modelled. Based on an energetic and economic analysis, the optimal configuration is a geometrical similar turbine of three times the volume flow rate of one feed pump. The PERS has been proven to be a cost reductive and clean tool. For a 100 MW power plant of 30-year lifetime the investment cost is 1.26 M$ and the annual cash flow is 0.89 M$, while for a plant of 20 MW these values are 0.26 M$ and 0.19 M$, respectively

Design of reactive power procurement in deregulated electricity market

African Journals Online (AJOL)

user

novel reactive power procurement model is proposed, which ensure secure and ..... The simulation is performed in the Matlab. .... focus of this paper is a reactive procurement market model, which is a basically two-step optimization process.

Adaptive Reactive Power Control of PV Power Plants for Improved Power Transfer Capability under Ultra-Weak Grid Conditions

DEFF Research Database (Denmark)

Yang, Dongsheng; Wang, Xiongfei; Liu, Fangcheng

2018-01-01

with the unity power factor. Then, considering the reactive power compensation from PV inverters, the minimum SCR in respect to Power Factor (PF) is derived, and the optimized coordination of the active and reactive power is exploited. It is revealed that the power transfer capability of PV power plant under...... of a 200 MW PV power plant demonstrate that the proposed method can ensure the rated power transfer of PV power plant with the SCR of 1.25, provided that the PV inverters are operated with the minimal PF=0.9.......This paper analyzes the power transfer limitation of the PV power plant under the ultra-weak grid condition, i.e., when the Short-Circuit Ratio (SCR) is close to 1. It explicitly identifies that a minimum SCR of 2 is required for the PV power plant to deliver the rated active power when operating...

A stochastic framework for clearing of reactive power market

International Nuclear Information System (INIS)

Amjady, N.; Rabiee, A.; Shayanfar, H.A.

2010-01-01

This paper presents a new stochastic framework for clearing of day-ahead reactive power market. The uncertainty of generating units in the form of system contingencies are considered in the reactive power market-clearing procedure by the stochastic model in two steps. The Monte-Carlo Simulation (MCS) is first used to generate random scenarios. Then, in the second step, the stochastic market-clearing procedure is implemented as a series of deterministic optimization problems (scenarios) including non-contingent scenario and different post-contingency states. In each of these deterministic optimization problems, the objective function is total payment function (TPF) of generators which refers to the payment paid to the generators for their reactive power compensation. The effectiveness of the proposed model is examined based on the IEEE 24-bus Reliability Test System (IEEE 24-bus RTS). (author)

Offshore wind energy storage concept for cost-of-rated-power savings

International Nuclear Information System (INIS)

Qin, Chao; Saunders, Gordon; Loth, Eric

2017-01-01

Highlights: •Investigated CAES + HPT system concept for offshore wind energy; •Validated cost model for offshore wind farm including CAPEX and OPEX items; •Quantified cost-of-rated-power savings associated with CAES + HPT concept; •Estimated savings of 21.6% with CAES + HPT for a sample $2.92 billion project. -- Abstract: The size and number of off-shore wind turbines over the next decade is expected to rapidly increase due to the high wind energy potential and the ability of such farms to provide utility-scale energy. In this future, inexpensive and efficient on-site wind energy storage can be critical to address short-time (hourly) mismatches between wind supply and energy demand. This study investigates a compressed air energy storage (CAES) and hydraulic power transmission (HPT) system concept. To assess cost impact, the NREL Cost and Scaling Model was modified to improve accuracy and robustness for offshore wind farms with large turbines. Special attention was paid to the support structure, installation, electrical interface and connections, land leasing, and operations and maintenance cost items as well as specific increased/reduced costs reductions associated with CAES + HPT systems. This cost model was validated and applied to a sample $2.92 billion project Virginia Offshore case It was found that adaption of CAES + HPT can lead to a substantial savings of 21.6% of this 20-year lifetime cost by dramatically reducing capital and operating cost of the generator and power transmission components. However, there are several additional variables that can impact the off-shore energy policy and planning for this new CAES + HPT concept. Furthermore, these cost-savings are only first-order estimates based on linear mass-cost relationships, and thus detailed engineering and economic analysis are recommended.

Multiagent-Based Reactive Power Sharing and Control Model for Islanded Microgrids

DEFF Research Database (Denmark)

Chen, Feixiong; Chen, Minyou; Li, Qiang

2016-01-01

of the control model, in which the uncertainty of intermittent DGs, variations in load demands, as well as impacts of time delays are considered. The simulation results demonstrate the eectiveness of the control model in proportional reactive power sharing, and the plug and play capability of the control model......In islanded microgrids (MGs), the reactive power cannot be shared proportionally among distributed generators (DGs) with conventional droop control, due to the mismatch in feeder impedances. For the purpose of proportional reactive power sharing, a multiagent system (MAS) based distributed control...

Maximum power point tracking: a cost saving necessity in solar energy systems

Energy Technology Data Exchange (ETDEWEB)

Enslin, J H.R. [Stellenbosch Univ. (South Africa). Dept. of Electrical and Electronic Engineering

1992-12-01

A well engineered renewable remote energy system, utilizing the principal of Maximum Power Point Tracking (MPPT) can improve cost effectiveness, has a higher reliability and can improve the quality of life in remote areas. A high-efficient power electronic converter, for converting the output voltage of a solar panel, or wind generator, to the required DC battery bus voltage has been realized. The converter is controlled to track the maximum power point of the input source under varying input and output parameters. Maximum power point tracking for relative small systems is achieved by maximization of the output current in a battery charging regulator, using an optimized hill-climbing, inexpensive microprocessor based algorithm. Through practical field measurements it is shown that a minimum input source saving of between 15 and 25% on 3-5 kWh/day systems can easily be achieved. A total cost saving of at least 10-15% on the capital cost of these systems are achievable for relative small rating Remote Area Power Supply (RAPS) systems. The advantages at large temperature variations and high power rated systems are much higher. Other advantages include optimal sizing and system monitor and control. (author).

Index-based reactive power compensation scheme for voltage regulation

Science.gov (United States)

Dike, Damian Obioma

2008-10-01

Increasing demand for electrical power arising from deregulation and the restrictions posed to the construction of new transmission lines by environment, socioeconomic, and political issues had led to higher grid loading. Consequently, voltage instability has become a major concern, and reactive power support is vital to enhance transmission grid performance. Improved reactive power support to distressed grid is possible through the application of relatively unfamiliar emerging technologies of "Flexible AC Transmission Systems (FACTS)" devices and "Distributed Energy Resources (DERS)." In addition to these infrastructure issues, a lack of situational awareness by system operators can cause major power outages as evidenced by the August 14, 2003 widespread North American blackout. This and many other recent major outages have highlighted the inadequacies of existing power system indexes. In this work, a novel "Index-based reactive compensation scheme" appropriate for both on-line and off-line computation of grid status has been developed. A new voltage stability index (Ls-index) suitable for long transmission lines was developed, simulated, and compared to the existing two-machine modeled L-index. This showed the effect of long distance power wheeling amongst regional transmission organizations. The dissertation further provided models for index modulated voltage source converters (VSC) and index-based load flow analysis of both FACTS and microgrid interconnected power systems using the Newton-Raphson's load flow model incorporated with multi-FACTS devices. The developed package has been made user-friendly through the embodiment of interactive graphical user interface and implemented on the IEEE 14, 30, and 300 bus systems. The results showed reactive compensation has system wide-effect, provided readily accessible system status indicators, ensured seamless DERs interconnection through new islanding modes and enhanced VSC utilization. These outcomes may contribute

Intelligent control of energy-saving power generation system

Energy Technology Data Exchange (ETDEWEB)

Zhang, Zhiyuan; Zhang, Guoqing; Guo, Zhizhong [Harbin Institute of Technology, Harbin (China). Dept. of Electrical Engineering

2013-07-01

Highway power generation system which is environmentally friendly and sustainable provides an innovative method of energy conversion. It is also as a kind of city science and technology innovation, which has the characteristics of environmental protection and sustainable utilization. Making full use of vehicle impact speed control humps, we design a new kind of highway speed control humps combined with solar electric generation system integration. Developing green energy, energy saving and environment protection can be achieved.

An islanding microgrid reactive power sharing scheme enhanced by programmed virtual impedances

DEFF Research Database (Denmark)

He, Jinwei; Li, Yun Wei; Guerrero, Josep M.

2012-01-01

harmonic currents. With the knowledge of feeder impedances, reactive power sharing performance can be enhanced by the regulation of DG unit output virtual impedance. The proposed method realizes accurate real and reactive power sharing in proportion to DG unit rated power. Simulated and experimental...

Basic study on dynamic reactive-power control method with PV output prediction for solar inverter

Directory of Open Access Journals (Sweden)

Ryunosuke Miyoshi

2016-01-01

Full Text Available To effectively utilize a photovoltaic (PV system, reactive-power control methods for solar inverters have been considered. Among the various methods, the constant-voltage control outputs less reactive power compared with the other methods. We have developed a constant-voltage control to reduce the reactive-power output. However, the developed constant-voltage control still outputs unnecessary reactive power because the control parameter is constant in every waveform of the PV output. To reduce the reactive-power output, we propose a dynamic reactive-power control method with a PV output prediction. In the proposed method, the control parameter is varied according to the properties of the predicted PV waveform. In this study, we performed numerical simulations using a distribution system model, and we confirmed that the proposed method reduces the reactive-power output within the voltage constraint.

Extended reactivity trace curves for nuclear power control with no power shooting

Energy Technology Data Exchange (ETDEWEB)

Ratemi, W M; Elbuni, M S [Faculty of engineering, Al Fateh universty Tripoli (Libyan Arab Jamahiriya)

1995-10-01

This paper introduces a new concept of reactivity trace curve (RTC) for nuclear power control with no power shooting. The concept is based on recent work of bernard et al. on the dynamic period of nuclear reactors. RTC-method is simulated for both a static effective decay constant corresponding to a one-group delayed neutrons model, and a dynamic effective decay constant corresponding to a six-group delayed neutrons model. A fitting to the RTC of a six-group reactor model resulted in a closed from formula for the RTC that couples the effect of both static and dynamic decay constants. Hence, introducing two `fingerprints` for the reactor in concern to identify a closed from RTC formula capable of controlling the reactor power. Integration of the RTC with control rod integral curves results in the {rho}-z-t diagram. This diagram relates the amount of recommended reactivity (RTC), the position of control rod, and the time required for power control. 8 figs.

Extended reactivity trace curves for nuclear power control with no power shooting

International Nuclear Information System (INIS)

Ratemi, W. M.; Elbuni, M. S.

1995-01-01

This paper introduces a new concept of reactivity trace curve (RTC) for nuclear power control with no power shooting. The concept is based on recent work of bernard et al. on the dynamic period of nuclear reactors. RTC-method is simulated for both a static effective decay constant corresponding to a one-group delayed neutrons model, and a dynamic effective decay constant corresponding to a six-group delayed neutrons model. A fitting to the RTC of a six-group reactor model resulted in a closed from formula for the RTC that couples the effect of both static and dynamic decay constants. Hence, introducing two 'fingerprints' for the reactor in concern to identify a closed from RTC formula capable of controlling the reactor power. Integration of the RTC with control rod integral curves results in the ρ-z-t diagram. This diagram relates the amount of recommended reactivity (RTC), the position of control rod, and the time required for power control. 8 figs

Reactive power compensation. System service - line quality. 2. ed.; Blindleistungskompensation. Systemdienstleistung - Netzqualitaet

Energy Technology Data Exchange (ETDEWEB)

Grosse-Gehling, Martin; Just, Wolfgang; Reese, Juergen; Schlabbach, Juergen

2013-11-01

Reactive power compensation is playing an increasingly important role as the need for an efficient use of operating equipment and power grids continues to grow. This book presents the fundamentals of reactive power compensation in low and medium voltage grids, offering a wealth of application and calculation examples that will further the reader's understanding of the following topics: 1. design, dimensioning and operation of capacitors and capacitor installations; 2. long-term stability and ageing of capacitor installations; 3. use of passive and active filters; 4. improvement of voltage quality by means of filters and capacitor installations; 5. provision of reactive power compensation by means of power electronics; 6. costs and economic efficiency of reactive power compensation and filter equipment; 7. considerations from the viewpoint of the power supply industry; price regulations; 8. information requirements concerning PCB-containing capacitors; 9. climate protection and energy efficiency through reactive power compensation; 10. technical connection requirements and guidelines; 11. special technical issues concerning the use of reactive power compensation installations. [German] Die Blindleistungskompensation gewinnt angesichts der Notwendigkeit zur erhoehten Ausnutzung der Betriebsmittel und Netze zunehmend an Bedeutung. In diesem Buch werden die Grundlagen der Blindleistungskompensation in Nieder- und Mittelspannungsnetzen beschrieben und folgende Themen anhand zahlreicher Anwendungs- und Berechnungsbeispiele vertieft: 1. Aufbau, Auslegung und Betrieb von Kondensatoren und Kondensatoranlagen, 2. Langzeitstabilitaet und Alterung von Kondensatoranlagen, 3. Einsatz passiver und aktiver Filter, 4. Verbesserung der Spannungsqualitaet durch Filter und Kondensatoranlagen, 5. Blindleistungsbereitstellung mit Leistungselektronik, 6. Kosten und Wirtschaftlichkeit von Kompensations- und Filteranlagen, 7. Elektrizitaetswirtschaftliche Betrachtungen

Reactive power planning with FACTS devices using gravitational search algorithm

Directory of Open Access Journals (Sweden)

Biplab Bhattacharyya

2015-09-01

Full Text Available In this paper, Gravitational Search Algorithm (GSA is used as optimization method in reactive power planning using FACTS (Flexible AC transmission system devices. The planning problem is formulated as a single objective optimization problem where the real power loss and bus voltage deviations are minimized under different loading conditions. GSA based optimization algorithm and particle swarm optimization techniques (PSO are applied on IEEE 30 bus system. Results show that GSA can also be a very effective tool for reactive power planning.

Review of Active and Reactive Power Sharing Strategies in Hierarchical Controlled Microgrids

DEFF Research Database (Denmark)

Han, Yang; Li, Hong; Shen, Pan

2017-01-01

Microgrids consist of multiple parallel-connected distributed generation (DG) units with coordinated control strategies, which are able to operate in both grid-connected and islanded mode. Microgrids are attracting more and more attention since they can alleviate the stress of main transmission...... systems, reduce feeder losses, and improve system power quality. When the islanded microgrids are concerned, it is important to maintain system stability and achieve load power sharing among the multiple parallel-connected DG units. However, the poor active and reactive power sharing problems due...... in this paper for active power sharing. Moreover, nonlinear and unbalanced loads could further affect the reactive power sharing when regulating the active power, and it is difficult to share the reactive power accurately only by using the enhanced virtual impedance method. Therefore, the hierarchical control...

Saving Energy and Money: A Lesson in Computer Power Management

Science.gov (United States)

Lazaros, Edward J.; Hua, David

2012-01-01

In this activity, students will develop an understanding of the economic impact of technology by estimating the cost savings of power management strategies in the classroom. Students will learn how to adjust computer display settings to influence the impact that the computer has on the financial burden to the school. They will use mathematics to…

Blind spot in free power market debate. Reactive power problems are unavoidable

International Nuclear Information System (INIS)

Maessen, T.

2002-01-01

Import restrictions, switching problems, remotely readable meters appear to be temporary problems in a liberalised power market, according to statement of the Dutch the government. However, the issues surrounding reactive power management in the Dutch transmission and distribution networks are of a far more fundamental nature. The import of cheap foreign electricity could overload the domestic power grid sufficiently to compromise the security of supply [nl

Characteristics of a reactor with power reactivity feedback

International Nuclear Information System (INIS)

Li Fengyu; Zhang Yusheng; Zhang Guangfu; Liu Ying

2008-01-01

The point-reactor model with power reactivity feedback becomes a nonlinear system. Its dynamic characteristic shows great complexity. According to the mathematic definition of stability in differential equation qualitative theory, the model of a reactor with power reactivity feedback is judged unstable. The equilibrium point is a saddle-node point. A portion of the trajectory in the neighborhood of the equilibrium point is parabolic fan curve, and the other is hyperbolic fan curve. Based on phase locus near the equilibrium point, it is pointed out that the model is still stable within physical limits. The difference between stabilities in the mathematical sense and in the physical sense is indicated. (authors)

Advanced configuration of hybrid passive filter for reactive power and harmonic compensation

OpenAIRE

Kececioglu, O. Fatih; Acikgoz, Hakan; Sekkeli, Mustafa

2016-01-01

Harmonics is one of the major power quality problems for power systems. The harmonics can be eliminated by power filters such as passive, active, and hybrid. In this study, a new passive filter configuration has been improved in addition to the existing passive filter configurations. Conventional hybrid passive filters are not successful to compensate rapidly changing reactive power demand. The proposed configure are capable of compensating both harmonics and reactive power at the same time. ...

Local Reactive Power Control Methods for Overvoltage Prevention of Distributed Solar Inverters in Low-Voltage Grids

DEFF Research Database (Denmark)

Demirok, Erhan; Gonzalez, Pablo Casado; Frederiksen, Kenn H. B.

2011-01-01

on sensitivity analysis. The sensitivity analysis shows that the same amount of reactive power becomes more effective for grid voltage support if the solar inverter is located at the end of a feeder. Based on this fundamental knowledge, a location-dependent power factor set value can be assigned to each inverter......voltage (LV) grids by means of solar inverters with reactive power control capability. This paper underlines weak points of standard reactive power strategies which are already imposed by certain grid codes, and then, the study introduces a new reactive power control method that is based......, and the grid voltage support can be achieved with less total reactive power consumption. In order to prevent unnecessary reactive power absorption from the grid during admissible voltage range or to increase reactive power contribution from the inverters that are closest to the transformer during grid...

An Improved Droop Control Strategy for Reactive Power Sharing in Islanded Microgrid

DEFF Research Database (Denmark)

Han, Hua; Liu, Yao; Sun, Yao

2015-01-01

For microgrid in islanded operation, due to the effects of mismatched line impedance, the reactive power could not be shared accurately with the conventional droop method. To improve the reactive power sharing accuracy, this paper proposes an improved droop control method. The proposed method...... in output voltage amplitude. Therefore, the voltage recovery operation is proposed to compensate the decrease. The needed communication in this method is very simple, and the plug-and-play is reserved. Simulations and experimental results show that the improved droop controller can share load active...... and reactive power, improve the power quality of the microgrid, and also have a good dynamic performance....

Strategies for Power/Energy Saving in Distribution Networks

Directory of Open Access Journals (Sweden)

GRIGORAS, G.

2010-05-01

Full Text Available The power/energy losses reduction in distribution systems is an important issue during planning and operation, with important technical and economical implications. Thus, the energy losses minimization implies not only the technical improvement of the network, through its renewal with the introduction of the technological innovations in the equipment and circuit components as well as the optimal planning of the design and development of the network, but also requires the use of the methods and software tools to facilitate the operation process. The paper presents a strategy for power/energy saving which replacement of the 6 kV voltage level with 20 kV voltage level in correlation with the extent of using efficient transformers. In this line, different urban distribution networks were analyzed using fuzzy techniques.

ONU power saving modes in next generation optical access networks: progress, efficiency and challenges.

Science.gov (United States)

Dixit, Abhishek; Lannoo, Bart; Colle, Didier; Pickavet, Mario; Demeester, Piet

2012-12-10

The optical network unit (ONU), installed at a customer's premises, accounts for about 60% of power in current fiber-to-the-home (FTTH) networks. We propose a power consumption model for the ONU and evaluate the ONU power consumption in various next generation optical access (NGOA) architectures. Further, we study the impact of the power savings of the ONU in various low power modes such as power shedding, doze and sleep.

Comprehensive Reactive Power Support of DFIG Adapted to Different Depth of Voltage Sags

Directory of Open Access Journals (Sweden)

Yangwu Shen

2017-06-01

Full Text Available The low voltage ride-through (LVRT capability of the doubly-fed induction generator (DFIG significantly impacts upon the integration of wind power into the power grid. This paper develops a novel comprehensive control strategy to enhance the LVRT and reactive power support capacities of the DFIG by installing the energy storage system (ESS. The ESS is connected to the DC-link capacitor of the DFIG and used to regulate the DC-link voltage during normal or fault operations. The unbalanced power between the captured wind power and the power injected to the grid during the transient process is absorbed or compensated by the ESS. The rotor-side converter (RSC is used to control the maximum power production and the grid-side converter (GSC is used to control the reactive power before participating in the voltage support. When the supply voltage continues to drop, the rotor speed is increased by controlling the RSC to realize the LVRT capability and help the GSC further enhance the reactive power support capability. The capacity of the GSC is dedicated to injecting the reactive power to the grid. An auxiliary transient pitch angle controller is proposed to protect the generator’s over speed. Both RSC and GSC act as reactive power sources to further enhance the voltage support capability with serious voltage sags. Simulations based on a single-machine infinite-bus power system verify the effectiveness of the developed comprehensive control strategy.

Operational experience with reactive power control methods optimized for tokamak power supplies

International Nuclear Information System (INIS)

Sihler, C.; Huart, M.; Kaesemann, C.-P.; Streibl, B.

2003-01-01

The power and energy of the ASDEX Upgrade (AUG) tokamak are provided by two separate 10.5 kV, 110-85 Hz networks based on the flywheel generators EZ3-EZ4 in addition to the generator EZ2 dedicated to the toroidal field coil. The 10.5 kV networks supply the thyristor converters allowing fast control of the DC currents in the AUG poloidal field coils. Two methods for improving the load power factor in the present experimental campaign of AUG have been investigated, namely the control of the phase-to-neutral voltage in thyristor converters fitted with neutral thyristors, such as the new 145 MVA modular thyristor converter system (Group 6), and reactive power control achieved by means of static VAr compensators (SVC). The paper shows that reliable compensation up to 90 MVAr was regularly achieved and that electrical transients in SVC modules can be kept at an acceptable level. The paper will discuss the results from the reactive power reduction by SVC and neutral thyristor control and draw a comparative conclusion

Application of the ant colony search algorithm to reactive power pricing in an open electricity market

International Nuclear Information System (INIS)

Ketabi, Abbas; Alibabaee, Ahmad; Feuillet, R.

2010-01-01

Reactive power management is essential to transfer real energy and support power system security. Developing an accurate and feasible method for reactive power pricing is important in the electricity market. In conventional optimal power flow models the production cost of reactive power was ignored. In this paper, the production cost of reactive power and investment cost of capacitor banks were included into the objective function of the OPF problem. Then, using ant colony search algorithm, the optimal problem was solved. Marginal price theory was used for calculation of the cost of active and reactive power at each bus in competitive electric markets. Application of the proposed method on IEEE 14-bus system confirms its validity and effectiveness. Results from several case studies show clearly the effects of various factors on reactive power price. (author)

Stochastic reactive power dispatch in hybrid power system with intermittent wind power generation

International Nuclear Information System (INIS)

Taghavi, Reza; Seifi, Ali Reza; Samet, Haidar

2015-01-01

Environmental concerns besides fuel costs are the predominant reasons for unprecedented escalating integration of wind turbine on power systems. Operation and planning of power systems are affected by this type of energy due to the intermittent nature of wind speed inputs with high uncertainty in the optimization output variables. Consequently, in order to model this high inherent uncertainty, a PRPO (probabilistic reactive power optimization) framework should be devised. Although MC (Monte-Carlo) techniques can solve the PRPO with high precision, PEMs (point estimate methods) can preserve the accuracy to attain reasonable results when diminishing the computational effort. Also, this paper introduces a methodology for optimally dispatching the reactive power in the transmission system, while minimizing the active power losses. The optimization problem is formulated as a LFP (linear fuzzy programing). The core of the problem lay on generation of 2m + 1 point estimates for solving PRPO, where n is the number of input stochastic variables. The proposed methodology is investigated using the IEEE-14 bus test system equipped with HVDC (high voltage direct current), UPFC (unified power flow controller) and DFIG (doubly fed induction generator) devices. The accuracy of the method is demonstrated in the case study. - Highlights: • This paper uses stochastic loads in optimization process. • AC–DC load flow is modified to use some advantages of DC part in optimization process. • UPFC and DFIG are simulated in a way that could be effective in optimization process. • Fuzzy set has been used as an uncertainty analysis tool in the optimization

THE IMPACT OF POWER COEFFICIENT OF REACTIVITY ON CANDU 6 REACTORS

Directory of Open Access Journals (Sweden)

D. KASTANYA

2013-10-01

Full Text Available The combined effects of reactivity coefficients, along with other core nuclear characteristics, determine reactor core behavior in normal operation and accident conditions. The Power Coefficient of Reactivity (PCR is an aggregate indicator representing the change in reactor core reactivity per unit change in reactor power. It is an integral quantity which captures the contributions of the fuel temperature, coolant void, and coolant temperature reactivity feedbacks. All nuclear reactor designs provide a balance between their inherent nuclear characteristics and the engineered reactivity control features, to ensure that changes in reactivity under all operating conditions are maintained within a safe range. The CANDU® reactor design takes advantage of its inherent nuclear characteristics, namely a small magnitude of reactivity coefficients, minimal excess reactivity, and very long prompt neutron lifetime, to mitigate the demand on the engineered systems for controlling reactivity and responding to accidents. In particular, CANDU reactors have always taken advantage of the small value of the PCR associated with their design characteristics, such that the overall design and safety characteristics of the reactor are not sensitive to the value of the PCR. For other reactor design concepts a PCR which is both large and negative is an important aspect in the design of their engineered systems for controlling reactivity. It will be demonstrated that during Loss of Regulation Control (LORC and Large Break Loss of Coolant Accident (LBLOCA events, the impact of variations in power coefficient, including a hypothesized larger than estimated PCR, has no safety-significance for CANDU reactor design. Since the CANDU 6 PCR is small, variations in the range of values for PCR on the performance or safety of the reactor are not significant.

Calculation methods of reactivity using derivatives of nuclear power and Filter fir

International Nuclear Information System (INIS)

Diaz, Daniel Suescun

2007-01-01

This work presents two new methods for the solution of the inverse point kinetics equation. The first method is based on the integration by parts of the integral of the inverse point kinetics equation, which results in a power series in terms of the nuclear power in time dependence. Applying some conditions to the nuclear power, the reactivity is represented as first and second derivatives of this nuclear power. This new calculation method for reactivity has special characteristics, amongst which the possibility of using different sampling periods, and the possibility of restarting the calculation, after its interruption associated it with a possible equipment malfunction, allowing the calculation of reactivity in a non-continuous way. Apart from this reactivity can be obtained with or without dependency on the nuclear power memory. The second method is based on the Laplace transform of the point kinetics equations, resulting in an expression equivalent to the inverse kinetics equation as a function of the power history. The reactivity can be written in terms of the summation of convolution with response to impulse, characteristic of a linear system. For its digital form the Z-transform is used, which is the discrete version of the Laplace transform. In this method it can be pointed out that the linear part is equivalent to a filter named Finite Impulse Response (Fir). The Fir filter will always be, stable and non-varying in time, and, apart from this, it can be implemented in the non-recursive way. This type of implementation does not require feedback, allowing the calculation of reactivity in a continuous way. The proposed methods were validated using signals with random noise and showing the relationship between the reactivity difference and the degree of the random noise. (author)

Optimal Control of Wind Farms for Coordinated TSO-DSO Reactive Power Management

Directory of Open Access Journals (Sweden)

David Sebastian Stock

2018-01-01

Full Text Available The growing importance of renewable generation connected to distribution grids requires an increased coordination between transmission system operators (TSOs and distribution system operators (DSOs for reactive power management. This work proposes a practical and effective interaction method based on sequential optimizations to evaluate the reactive flexibility potential of distribution networks and to dispatch them along with traditional synchronous generators, keeping to a minimum the information exchange. A modular optimal power flow (OPF tool featuring multi-objective optimization is developed for this purpose. The proposed method is evaluated for a model of a real German 110 kV grid with 1.6 GW of installed wind power capacity and a reduced order model of the surrounding transmission system. Simulations show the benefit of involving wind farms in reactive power support reducing losses both at distribution and transmission level. Different types of setpoints are investigated, showing the feasibility for the DSO to fulfill also individual voltage and reactive power targets over multiple connection points. Finally, some suggestions are presented to achieve a fair coordination, combining both TSO and DSO requirements.

Use a renewable energy sources and latest power-saving technologies in the the Republic Kazakstan

International Nuclear Information System (INIS)

Gulevich, N.V.

1996-01-01

The subject of alternative power in Kazakstan is brought up. Wind-, hydro-, solar power, biogas installation can improve the Republic power base. The main directions of activity of A. Einstein International Power engineering Academy on involving renewable energy sources and latest power-saving technologies to Republic of Kazakstan's fuel-power balance is given. It should be noted that renewable power engineering usually handles reversible energy sources and reserved power cycles. (author)

Energy saved neon sign lighting power supply for photovoltaic systems

Energy Technology Data Exchange (ETDEWEB)

Tanitteerapan, T.; Dokpikul, S.; Arunrungrasmi, S. [King Mongkut Univ. of Technology Thonburi, Bangmod, Tungkru, Bangkok (Thailand). Dept. of Electrical Technology Education, Faculty of Industrial Education

2007-07-01

Petroleum oil, natural gas and fossil fuels are commonly used in power plants for electrical power generation. However, because of their negative environmental impacts, energy and environmental savings from renewable energy resources are necessary choices. Solar energy can be converted to the electrical voltage by using solar arrays. This process can be used in many electrical applications. This paper introduced a neon sign lighting power supply for a small photovoltaic powered stand-alone commercial advertising board for a remote area in Thailand. The circuit implementation was very simple, consisting of an active switch device, a resonant capacitor and high frequency transformer. The control also operated as a fixed frequency and fixed duty ratio controller. The paper discussed the principle of neon sign lighting, power circuit operation, and control circuit operation. To verify the proposed power supply, the circuit experiment of the proposed power supply for the neon sign lighting was applied to a 10 foot long, 10 millimeter diameter bulb. The neon sign was ignited smoothly with little power consumption. 2 refs., 1 tab., 10 figs.

Reactive power interconnection requirements for PV and wind plants : recommendations to NERC.

Energy Technology Data Exchange (ETDEWEB)

McDowell, Jason (General Electric, Schenectady, NY); Walling, Reigh (General Electric, Schenectady, NY); Peter, William (SunPower, Richmond, CA); Von Engeln, Edi (NV Energy, Reno, NV); Seymour, Eric (AEI, Fort Collins, CO); Nelson, Robert (Siemens Wind Turbines, Orlando, FL); Casey, Leo (Satcon, Boston, MA); Ellis, Abraham; Barker, Chris. (SunPower, Richmond, CA)

2012-02-01

Voltage on the North American bulk system is normally regulated by synchronous generators, which typically are provided with voltage schedules by transmission system operators. In the past, variable generation plants were considered very small relative to conventional generating units, and were characteristically either induction generator (wind) or line-commutated inverters (photovoltaic) that have no inherent voltage regulation capability. However, the growing level of penetration of non-traditional renewable generation - especially wind and solar - has led to the need for renewable generation to contribute more significantly to power system voltage control and reactive power capacity. Modern wind-turbine generators, and increasingly PV inverters as well, have considerable dynamic reactive power capability, which can be further enhanced with other reactive support equipment at the plant level to meet interconnection requirements. This report contains a set of recommendations to the North-America Electricity Reliability Corporation (NERC) as part of Task 1-3 (interconnection requirements) of the Integration of Variable Generation Task Force (IVGTF) work plan. The report discusses reactive capability of different generator technologies, reviews existing reactive power standards, and provides specific recommendations to improve existing interconnection standards.

Reactive power balance in a distribution network with wind farms and CHPS

DEFF Research Database (Denmark)

Lund, Torsten; Nielsen, John Eli; Hylle, Per

2007-01-01

In Denmark, a large part of the electricity is generated by wind turbines and combined heat and power plants. Most of them are connected to the distribution systems. In periods with high wind speeds, large flows of reactive power have been observed between the 150kV and the 60 kV systems. The tra......In Denmark, a large part of the electricity is generated by wind turbines and combined heat and power plants. Most of them are connected to the distribution systems. In periods with high wind speeds, large flows of reactive power have been observed between the 150kV and the 60 kV systems....... The transfer of reactive power reduces the capacity of the lines, causes thermal losses and can in some cases reduce the voltage stability margin of the system. To identify the origin of the problem, an actual distribution system with a high penetration of wind power and distributed generation has been...

A Preliminary Analysis of the Economics of Using Distributed Energy as a Source of Reactive Power Supply

Energy Technology Data Exchange (ETDEWEB)

Li, Fangxing [ORNL; Kueck, John D [ORNL; Rizy, D Tom [ORNL; King, Thomas F [ORNL

2006-04-01

A major blackout affecting 50 million people in the Northeast United States, where insufficient reactive power supply was an issue, and an increased number of filings made to the Federal Energy Regulatory Commission by generators for reactive power has led to a closer look at reactive power supply and compensation. The Northeastern Massachusetts region is one such area where there is an insufficiency in reactive power compensation. Distributed energy due to its close proximity to loads seems to be a viable option for solving any present or future reactive power shortage problems. Industry experts believe that supplying reactive power from synchronized distributed energy sources can be 2 to 3 times more effective than providing reactive support in bulk from longer distances at the transmission or generation level. Several technology options are available to supply reactive power from distributed energy sources such as small generators, synchronous condensers, fuel cells or microturbines. In addition, simple payback analysis indicates that investments in DG to provide reactive power can be recouped in less than 5 years when capacity payments for providing reactive power are larger than $5,000/kVAR and the DG capital and installation costs are lower than $30/kVAR. However, the current institutional arrangements for reactive power compensation present a significant barrier to wider adoption of distributed energy as a source of reactive power. Furthermore, there is a significant difference between how generators and transmission owners/providers are compensated for reactive power supplied. The situation for distributed energy sources is even more difficult, as there are no arrangements to compensate independent DE owners interested in supplying reactive power to the grid other than those for very large IPPs. There are comparable functionality barriers as well, as these smaller devices do not have the control and communications requirements necessary for automatic

Power flattening and reactivity suppression strategies for the Canadian supercritical water reactor concept

International Nuclear Information System (INIS)

McDonald, M.; Colton, A.; Pencer, J.

2015-01-01

The Canadian supercritical water-cooled reactor (SCWR) is a conceptual heavy water moderated, supercritical light water cooled pressure tube reactor. In contrast to current heavy water power reactors, the Canadian SCWR will be a batch fuelled reactor. Associated with batch fuelling is a large beginning-of-cycle excess reactivity. Furthermore, radial power peaking arising as a consequence of batch refuelling must be mitigated in some way. In this paper, burnable neutron absorber (BNA) added to fuel and absorbing rods inserted into the core are considered for reactivity management and power flattening. A combination of approaches appears adequate to reduce the core radial power peaking, while also providing reactivity suppression. (author)

Reactive adsorption: A cleaner technology in nuclear power plants

International Nuclear Information System (INIS)

Marton, G.; Szanya, T.; Hanak, L.

1996-01-01

Cleaner technology prefers work with minimal loss and the wastes cause the less environmental damages. In the spirit of the previous sentence in the present paper reactive adsorption is investigated for the removal of radioactive nuclides from nuclear power plant decontamination solutions. During alkaline, oxidative decontamination of nuclear power plant equipment a radioactive solution is produced. Owing to the storing difficulties of radioactive solutions it is necessary to develop a method for the in situ treatment of radioactive, alkaline, oxidative decontamination solutions, and for the concentration of radioactive components. Reactive adsorption seems to be promising for this purpose. 3 refs., 8 figs., 1 tab

ACCOUNTING OF REACTIVE POWER COMPENSATION LEVEL AT PAYMENT CALCULATION OF TECHNOLOGICAL CONSUMPTION (LOSSES OF ELECTRIC POWER FOR ITS TRANSMISSION IN POWER NETWORK

Directory of Open Access Journals (Sweden)

E. P. Zabello

2005-01-01

Full Text Available The method is proposed to make a correction in payment for consumption of reactive energy and power which is attributed to deviation of actual activation energy losses for reactive power compensation from their standard value. It is recommended to calculate standard loss values for every voltage level and actual loss values are to be determined with the help of application of remote electronic accounting means in the current mode of power consumption.

Electrical engineering unit for the reactive power control of the load bus at the voltage instability

Science.gov (United States)

Kotenev, A. V.; Kotenev, V. I.; Kochetkov, V. V.; Elkin, D. A.

2018-01-01

For the purpose of reactive power control error reduction and decrease of the voltage sags in the electric power system caused by the asynchronous motors started the mathematical model of the load bus was developed. The model was built up of the sub-models of the following elements: a transformer, a transmission line, a synchronous and an asynchronous loads and a capacitor bank load, and represents the automatic reactive power control system taking into account electromagnetic processes of the asynchronous motors started and reactive power changing of the electric power system elements caused by the voltage fluctuation. The active power/time and reactive power/time characteristics based on the recommended procedure of the equivalent electric circuit parameters calculation were obtained. The derived automatic reactive power control system was shown to eliminate the voltage sags in the electric power system caused by the asynchronous motors started.

A Hybrid Optimization Method for Reactive Power and Voltage Control Considering Power Loss Minimization

DEFF Research Database (Denmark)

Liu, Chengxi; Qin, Nan; Bak, Claus Leth

2015-01-01

This paper proposes a hybrid optimization method to optimally control the voltage and reactive power with minimum power loss in transmission grid. This approach is used for the Danish automatic voltage control (AVC) system which is typically a non-linear non-convex problem mixed with both...

Marginal costs of water savings from cooling system retrofits: a case study for Texas power plants

Science.gov (United States)

Loew, Aviva; Jaramillo, Paulina; Zhai, Haibo

2016-10-01

The water demands of power plant cooling systems may strain water supply and make power generation vulnerable to water scarcity. Cooling systems range in their rates of water use, capital investment, and annual costs. Using Texas as a case study, we examined the cost of retrofitting existing coal and natural gas combined-cycle (NGCC) power plants with alternative cooling systems, either wet recirculating towers or air-cooled condensers for dry cooling. We applied a power plant assessment tool to model existing power plants in terms of their key plant attributes and site-specific meteorological conditions and then estimated operation characteristics of retrofitted plants and retrofit costs. We determined the anticipated annual reductions in water withdrawals and the cost-per-gallon of water saved by retrofits in both deterministic and probabilistic forms. The results demonstrate that replacing once-through cooling at coal-fired power plants with wet recirculating towers has the lowest cost per reduced water withdrawals, on average. The average marginal cost of water withdrawal savings for dry-cooling retrofits at coal-fired plants is approximately 0.68 cents per gallon, while the marginal recirculating retrofit cost is 0.008 cents per gallon. For NGCC plants, the average marginal costs of water withdrawal savings for dry-cooling and recirculating towers are 1.78 and 0.037 cents per gallon, respectively.

Energy Saving Performance Analysis of An Inverter-based Regenerative Power Re-utilization Device for Urban Rail Transit

Science.gov (United States)

Li, Jin; Qiu, Zhiling; Hu, Leilei

2018-04-01

The inverter-based regenerative braking power utilization devices can re-utilize the regenerative energy, thus reduce the energy consumption of urban rail transit. In this paper the power absorption principle of the inverter-based device is introduced, then the key influencing factors of energy saving performance are analyzed based on the absorption model. The field operation data verified that the control DC voltage plays an important role and lower control DC voltage yields more energy saving. Also, the one year energy saving performance data of an inverter-based re-utilization device located in NanJing S8 line is provided, and more than 1.2 million kWh energy is recovered in the one year operation.

Reactive power compensation and loss reduction in large industrial enterprises

Energy Technology Data Exchange (ETDEWEB)

Jovanovic, S; Gajic, B; Mijailovic, S [Institute Nikola Tesla, Beograd (Yugoslavia)

1991-12-01

This paper considers the reactive power compensation and the active power and energy loss reduction of large radial power networks in the Serbian mine and smelting industry. It gives an efficient optimization procedure for positioning and sizing capacitors in large industrial systems integrated with a simple network analysis method. (Author).

Coordinated Reactive Power and Voltage Management for Offshore Wind Farms with AC-connection

DEFF Research Database (Denmark)

Heussen, Kai

2008-01-01

This paper analyzes voltage and reactive power in a wind farm in dependence on switchable shunt and tap-changer settings in connection with the control ranges of flexible reactive power sources. Attention is paid to their interdependent effects on central control variables, such as voltage...... in the collection grid, reactive power exported to the grid and internal active power losses. An aggregated steady-state model of an offshore wind farm is presented and a reduced mathematical representation suitable for symbolic analysis is developed. A coordination scheme is proposed to coordinate fast continuous...... control inputs with slow tap-changing devices using a short-term prediction. The proposed scheme is aimed at balancing cost factors such as wear of switching components, active power loss within the wind farm and STATCOM capacity....

How EPRI [Electric Power Research Institute] helps utilities save money

International Nuclear Information System (INIS)

Anon.

1996-01-01

A number of case studies are presented which illustrate how the work of the Electric Power Research Institute in the USA has enabled nuclear utilities to save money. The areas covered by the examples are: steam generator tube repair; streamlining of reliability centred maintenance; cost effective instrumentation and control maintenance; reducing the frequency of instrument calibration; optimising the engineering change process; detecting and reducing fuel failure; extending the qualified life of equipment. (U.K.)

Reliability Analysis of Single-Phase PV Inverters with Reactive Power Injection at Night Considering Mission Profiles

DEFF Research Database (Denmark)

Anurag, Anup; Yang, Yongheng; Blaabjerg, Frede

2015-01-01

loading, considering the operation outside active feed-in hours. An analytical lifetime model is then employed for lifetime quantization based on the Palgrem Miner rule. Thereafter, considering the lifetime reduction of the PV inverter under different mission profiles with reactive power injection......The widespread adoption of mixed renewables urgently require reactive power exchange at various feed-in points of the utility grid. Photovoltaic (PV) inverters are able to provide reactive power in a decentralized manner at the grid-connection points even outside active power feed-in operation......, especially at night when there is no solar irradiance. This serves as a motivation for utilizing the PV inverters at night for reactive power compensation. Thus, an analysis on the impact of reactive power injection by PV inverters outside feed-in operation on the thermal performance and the reliability has...

Strategy on energy saving reconstruction of distribution networks based on life cycle cost

Science.gov (United States)

Chen, Xiaofei; Qiu, Zejing; Xu, Zhaoyang; Xiao, Chupeng

2017-08-01

Because the actual distribution network reconstruction project funds are often limited, the cost-benefit model and the decision-making method are crucial for distribution network energy saving reconstruction project. From the perspective of life cycle cost (LCC), firstly the research life cycle is determined for the energy saving reconstruction of distribution networks with multi-devices. Then, a new life cycle cost-benefit model for energy-saving reconstruction of distribution network is developed, in which the modification schemes include distribution transformers replacement, lines replacement and reactive power compensation. In the operation loss cost and maintenance cost area, the operation cost model considering the influence of load season characteristics and the maintenance cost segmental model of transformers are proposed. Finally, aiming at the highest energy saving profit per LCC, a decision-making method is developed while considering financial and technical constraints as well. The model and method are applied to a real distribution network reconstruction, and the results prove that the model and method are effective.

Voltage Sag Mitigation and Load Reactive Power Compensation by UPQC

OpenAIRE

Ajitha, P; Jananisri, D

2014-01-01

This paper presents Unified Power Quality Conditioner(UPQC) that consist of series inverter and shunt inverter in back to back configuration which simultaneously compensate the power quality(PQ) problems of both voltage sag and load reactive power compensation . In this paper ,Neural network is tool which is considered for solving power quality problems. The simulation results from MATLAB/SIMULINK are discussed to validate the proposed method.

Heat savings in buildings in a 100% renewable heat and power system in Denmark with different shares of district heating

DEFF Research Database (Denmark)

Zvingilaite, Erika; Balyk, Olexandr

2014-01-01

levels of heat savings, which can be implemented by reducing heat transmission losses through building elements and by installing ventilation systems with heat recovery, in different future Danish heat and power system scenarios. Today almost 50% of heat demand in Denmark is covered by district heating......The paper examines implementation of heat saving measures in buildings in 2050, under the assumption that heat and power supply comes solely from renewable resources in Denmark.Balmorel – a linear optimisation model of heat and power sectors in Denmark is used for investigating economically viable....... A further expansion of district heating network in Denmark is assessed and penetration of heat savings is analysed in this context.If all heat saving measures, included in the model, are implemented, heat demand in Danish buildings in 2050 could be reduced by around 40%. Results show that it is cost...

An iterative method for controlling reactive power flow in boundary transformers

Energy Technology Data Exchange (ETDEWEB)

Trigo, Angel L.; Martinez, Jose L.; Riquelme, Jesus; Romero, Esther [Department of Electrical Engineering, University of Seville (Spain)

2011-02-15

This paper presents an operational tool designed to help the system operator to control the reactive power flow in transmission-subtransmission boundary transformers. The main objective is to determine the minimum number of control actions necessary to ensure that reactive power flows in transmission/subtransmission transformers remain within limits. The proposed iterative procedure combines the use of a linear programming problem and a load flow tool. The linear programming assumes a linear behaviour between dependent and control variables around an operating point, modelled with sensitivities. Experimental results regarding IEEE systems are provided comparing the performance of the proposed approach with that of a conventional optimal power flow. (author)

Optimal reactive power planning for distribution systems considering intermittent wind power using Markov model and genetic algorithm

Science.gov (United States)

Li, Cheng

Wind farms, photovoltaic arrays, fuel cells, and micro-turbines are all considered to be Distributed Generation (DG). DG is defined as the generation of power which is dispersed throughout a utility's service territory and either connected to the utility's distribution system or isolated in a small grid. This thesis addresses modeling and economic issues pertaining to the optimal reactive power planning for distribution system with wind power generation (WPG) units. Wind farms are inclined to cause reverse power flows and voltage variations due to the random-like outputs of wind turbines. To deal with this kind of problem caused by wide spread usage of wind power generation, this thesis investigates voltage and reactive power controls in such a distribution system. Consequently static capacitors (SC) and transformer taps are introduced into the system and treated as controllers. For the purpose of getting optimum voltage and realizing reactive power control, the research proposes a proper coordination among the controllers like on-load tap changer (OLTC), feeder-switched capacitors. What's more, in order to simulate its uncertainty, the wind power generation is modeled by the Markov model. In that way, calculating the probabilities for all the scenarios is possible. Some outputs with consecutive and discrete values have been used for transition between successive time states and within state wind speeds. The thesis will describe the method to generate the wind speed time series from the transition probability matrix. After that, utilizing genetic algorithm, the optimal locations of SCs, the sizes of SCs and transformer taps are determined so as to minimize the cost or minimize the power loss, and more importantly improve voltage profiles. The applicability of the proposed method is verified through simulation on a 9-bus system and a 30-bus system respectively. At last, the simulation results indicate that as long as the available capacitors are able to sufficiently

Simulation and study on reactivity disturbs dynamic character of HTR-10 nuclear power system

International Nuclear Information System (INIS)

Huang Xiaojin; Feng Yuankun

2002-01-01

In order to not only know 10 MW High Temperature Gas Cooled Reactor (HTR-10) nuclear power system's dynamic character more deeply but also to satisfy requirements of control system's design and analysis, the dynamic model of HTR-10 nuclear power system is established on the basis of dynamic model of HTR-10 nuclear system, which supplies turbine and generate electricity system model. Using this model, system's main variables' dynamic processes are simulated when control rod takes step reactivity disturb. The concussive progresses which is caused by reactivity disturb are analyzed. The results indicate that fuel temperature changing more slowly than nuclear power makes reactivity negative feedback not to restrain power changing, and then power concussive progress comes to being

Impact of Reactive Power Injection Outside Feed-In Hours on the Reliability of Photovoltaic Inverters

DEFF Research Database (Denmark)

Anurag, Anup; Yang, Yongheng; Blaabjerg, Frede

2015-01-01

, the analysis enables the translation from long-term mission profiles to device thermal loading, considering the operation at night. An analytical lifetime model is then used for lifetime quantization based on the Palgrem Miner rule. Thereafter, considering the lifetime reduction of the PV inverter......Current energy paradigm of mixed renewables seems to urgently require reactive power provision at various feed-in points of the utility grid. Photovoltaic (PV) inverters are able to provide reactive power in a decentralized manner at the grid-connection point even outside active power feed......-in operation, especially at night. This serves as a motivation for utilizing the PV inverters at night for reactive power compensation. Thus, a detailed analysis on the impact of reactive power injection by PV inverters outside feed-in operation on the thermal performance and also the reliability is performed...

Reactivity and Power Distribution Management in LEU-loaded Linear B and BR

International Nuclear Information System (INIS)

Hartanto, Donny; Kim, Yonghee

2013-01-01

In this paper, the relatively high excess reactivity issue during the initial transitional period was addressed. The design target is to achieve a maximum excess reactivity of about 1.0 dollar to prevent the possibility of the prompt jump critical accident. The initial core is divided into 2 radial Zr-zones in order to reduce the excess reactivity. By doing this, the power profile at the BOC can also be flattened. After the optimum initial core configuration has been found, the blanket region is also divided into 2 radial Zr-zones in order to flatten the power distribution at EOC. The neutronic analyses were all performed using the Monte Carlo code McCARD with ENDF-B/VII.0 library. It was found that by using the concave Zr-zoning in the initial core of B and BR, the maximum excess reactivity can be effectively lowered. The radial power profile can also be successfully flattened by using the Zr-zoning and concave initial core. The concave concept deserves more investigations for better performances of the B and BR core

Reactivity calculation with reduction of the nuclear power fluctuations

International Nuclear Information System (INIS)

Suescun Diaz, Daniel; Senra Martinez, Aquilino

2009-01-01

A new formulation is presented in this paper for the calculation of reactivity, which is simpler than the formulation that uses the Laplace and Z transforms. A treatment is also made to reduce the intensity of the noise found in the nuclear power signal used in the calculation of reactivity. Two classes of different filters are used for that. This treatment is based on the fact that the reactivity can be written by using the compose Simpson's rule resulting in a sum of two convolution terms with response to the impulse that is characteristic of a linear system. The linear part is calculated by using the filter named finite impulse response filter (FIR). The non-linear part is calculated using the filter exponentially adjusted by the least squares method, which does not cause attenuation in the reactivity calculation.

Reactivity calculation with reduction of the nuclear power fluctuations

Energy Technology Data Exchange (ETDEWEB)

Suescun Diaz, Daniel [COPPE/UFRJ, Programa de Engenharia Nuclear, Caixa Postal 68509, CEP 21941-914 RJ (Brazil)], E-mail: dsuescun@hotmail.com; Senra Martinez, Aquilino [COPPE/UFRJ, Programa de Engenharia Nuclear, Caixa Postal 68509, CEP 21941-914 RJ (Brazil)

2009-05-15

A new formulation is presented in this paper for the calculation of reactivity, which is simpler than the formulation that uses the Laplace and Z transforms. A treatment is also made to reduce the intensity of the noise found in the nuclear power signal used in the calculation of reactivity. Two classes of different filters are used for that. This treatment is based on the fact that the reactivity can be written by using the compose Simpson's rule resulting in a sum of two convolution terms with response to the impulse that is characteristic of a linear system. The linear part is calculated by using the filter named finite impulse response filter (FIR). The non-linear part is calculated using the filter exponentially adjusted by the least squares method, which does not cause attenuation in the reactivity calculation.

Multi-objective optimal reactive power dispatch to maximize power system social welfare in the presence of generalized unified power flow controller

Directory of Open Access Journals (Sweden)

Suresh Chintalapudi Venkata

2015-09-01

Full Text Available In this paper a novel non-linear optimization problem is formulated to maximize the social welfare in restructured environment with generalized unified power flow controller (GUPFC. This paper presents a methodology to optimally allocate the reactive power by minimizing voltage deviation at load buses and total transmission power losses so as to maximize the social welfare. The conventional active power generation cost function is modified by combining costs of reactive power generated by the generators, shunt capacitors and total power losses to it. The formulated objectives are optimized individually and simultaneously as multi-objective optimization problem, while satisfying equality, in-equality, practical and device operational constraints. A new optimization method, based on two stage initialization and random distribution processes is proposed to test the effectiveness of the proposed approach on IEEE-30 bus system, and the detailed analysis is carried out.

Effects of social participation and the emergence of voluntary social interactions on household power-saving practices in post-disaster Kanagawa, Japan

International Nuclear Information System (INIS)

Nakamura, Hidenori

2013-01-01

An online social survey was conducted to reveal household electricity-saving behaviour and its relationship with participation in social group activities, as well as face-to-face and online social interactions, i.e., information sources used and information dissemination through personal networks, in a disaster-affected region of Kanagawa, Japan, during the summer of 2011. The study confirms the positive contribution of respondents’ participation in social group activities to the number of power-saving practices conducted. It also reveals the emergence of voluntary social face-to-face and/or online interactions for power-saving. The study suggests it would be useful to provide effective information to proactive individuals who are closely engaged in power-saving in households and who are proactively disseminating power-saving information practices to others. Such individuals include (1) women who have school-children and who are proactively engaging in the social interactions of their children’s schools, other parents, neighbours, as well as their own parents and relatives; and (2) men and women who are using various kinds of online interaction tools and are also engaged in face-to-face social interactions

Reduced Cost of Reactive Power in Doubly Fed Induction Generator Wind Turbine System with Optimized Grid Filter

DEFF Research Database (Denmark)

Zhou, Dao; Blaabjerg, Frede; Franke, Toke

2014-01-01

The modern grid requirement has caused that the wind power system behaves more like conventional rotating generators and it is able to support certain amount of the reactive power. For a typical doubly-fed induction generator wind turbine system, the reactive power can be supported either through...... for the generator and the wind power converter in terms of the reactive power done by the rotor-side converter or the grid-side converter with various grid filters. Afterwards, the annual energy loss is also estimated based on yearly wind profile. Finally, experimental results of the loss distribution are performed...... the rotor-side converter or the grid-side converter. This paper firstly compares the current ripples and supportive reactive power ranges between the conventional L and optimized LCL filter, if the reactive power is injected from the grid-side converter. Then, the loss distribution is evaluated both...

Reduced Cost of Reactive Power in Doubly Fed Induction Generator Wind Turbine System With Optimized Grid Filter

DEFF Research Database (Denmark)

Zhou, Dao; Blaabjerg, Frede; Franke, Toke

2015-01-01

The modern grid requirement has caused that the wind power system behaves more like conventional rotating generators, and it is able to support certain amount of the reactive power. For a typical doubly fed induction generator (DFIG) wind turbine system, the reactive power can be supported either...... for the generator and the wind power converter in terms of the reactive power done by the rotor-side converter or the grid-side converter with various grid filters. Afterward, the annual energy loss is also estimated based on yearly wind profile. Finally, experimental results of the loss distribution are performed...... through the rotor-side converter or the grid-side converter. This paper first compares the current ripples and supportive reactive power ranges between the conventional L and optimized LCL filter, if the reactive power is injected from the grid-side converter. Then, the loss distribution is evaluated both...

Single-Phase Boost Inverter-Based Electric Vehicle Charger With Integrated Vehicle to Grid Reactive Power Compensation

DEFF Research Database (Denmark)

Wickramasinghe Abeywardana, Damith Buddika; Acuna, Pablo; Hredzak, Branislav

2018-01-01

Vehicle to grid (V2G) reactive power compensation using electric vehicle (EV) onboard chargers helps to ensure grid power quality by achieving unity power factor operation. However, the use of EVs for V2G reactive power compensation increases the second-order harmonic ripple current component...... from the grid, exposes the EV battery to these undesirable ripple current components for a longer period and discharges the battery due to power conversion losses. This paper presents a way to provide V2G reactive power compensation through a boost inverter-based single stage EV charger and a DC...

Active and reactive power control of a current-source PWM-rectifier using space vectors

Energy Technology Data Exchange (ETDEWEB)

Salo, M.; Tuusa, H. [Tampere University of Technology (Finland). Department of Electrical Engineering, Power Electronics

1997-12-31

In this paper the current-source PWM-rectifier with active and reactive power control is presented. The control system is realized using space vector methods. Also, compensation of the reactive power drawn by the line filter is discussed. Some simulation results are shown. (orig.) 8 refs.

A Method of Dynamic Extended Reactive Power Optimization in Distribution Network Containing Photovoltaic-Storage System

Science.gov (United States)

Wang, Wu; Huang, Wei; Zhang, Yongjun

2018-03-01

The grid-integration of Photovoltaic-Storage System brings some undefined factors to the network. In order to make full use of the adjusting ability of Photovoltaic-Storage System (PSS), this paper puts forward a reactive power optimization model, which are used to construct the objective function based on power loss and the device adjusting cost, including energy storage adjusting cost. By using Cataclysmic Genetic Algorithm to solve this optimization problem, and comparing with other optimization method, the result proved that: the method of dynamic extended reactive power optimization this article puts forward, can enhance the effect of reactive power optimization, including reducing power loss and device adjusting cost, meanwhile, it gives consideration to the safety of voltage.

An Indispensable Truth How Fusion Power Can Save the Planet

CERN Document Server

Chen, Francis F

2011-01-01

Both global warming and oil shortage can be solved by controlled fusion, a clean power source that will serve mankind for millennia.� The idea of hydrogen fusion as well as its difficulties are presented in non-technical language to dispel the notion that fusion is always 50 years away.� This book also summarizes the evidence for climate change and explains the principles of both fossil and "green" energy sources to show that fusion is the best alternative for central-station power in the near term as well as the far future. Praise for An Indispensable Truth: How Fusion Power Can Save the Planet: "In this study Professor Chen outlines the underlying physics, recent progress in achieving advanced plasmas and magnetic confinement, and hopes for the future. He recognizes the difficulties that remain in engineering a fusion reactor, but he remains optimistic regarding ultimate success, yet fearful of the consequences were we to fail."- James R. Schlesinger, former Chairman, Atomic Energy Commission; Director,...

Device for measuring active, reactive and apparent power

Energy Technology Data Exchange (ETDEWEB)

Bartosinski, E.; Wieland, J.

1982-09-30

The plan consists of a traditional electrodynamic mechanism for measuring power (IM) supplemented by three switches, two rectifiers, resistor, included in parallel, and phaseshifting throttle included in series with the voltage coil of the IM. This makes it possible by selection to perform three types of measurements: active power of alternating current or power of direct current, only the voltage coils and the IM current are engaged; reactive power, the resistor and the throttle are additionally engaged by the aforementioned method; complete (apparent) power--the current and the voltage are supplied directly to the IM coils, but in contrast to the first case, through rectifiers. The influence of the highest harmonic components of voltage and current which are not significant for industrial measurements can be eliminated in necessary cases using filtering devices.

Towards a Reactive Power Oscillation Damping Controller for Wind Power Plant Based on Full Converter Wind Turbines

DEFF Research Database (Denmark)

Knüppel, Thyge; Kumar, Sathess; Thuring, Patrik

2012-01-01

In this paper a power oscillation damping controller (POD) based on modulation of reactive power (Q POD) is analyzed where the modular and distributed characteristics of the wind power plant (WPP) are considered. For a Q POD it is essential that the phase of the modulated output is tightly...... contributes to a collective response. This ability is shown with a 150 wind turbine (WT) WPP with all WTs represented, and it is demonstrated that the WPP contributes to the inter-area damping. The work is based on a nonlinear, dynamic model of the 3.6 MW Siemens Wind Power WT....... controlled to achieve a positive damping contribution. It is investigated how a park level voltage, reactive power, and power factor control at different grid strengths interact with the Q POD in terms of a resulting phase shift. A WPP is modular and distributed and a WPP Q POD necessitate that each WT...

Power Saving Scheduling Scheme for Internet of Things over LTE/LTE-Advanced Networks

Directory of Open Access Journals (Sweden)

Yen-Wei Kuo

2015-01-01

Full Text Available The devices of Internet of Things (IoT will grow rapidly in the near future, and the power consumption and radio spectrum management will become the most critical issues in the IoT networks. Long Term Evolution (LTE technology will become a promising technology used in IoT networks due to its flat architecture, all-IP network, and greater spectrum efficiency. The 3rd Generation Partnership Project (3GPP specified the Discontinuous Reception (DRX to reduce device’s power consumption. However, the DRX may pose unexpected communication delay due to missing Physical Downlink Control Channel (PDCCH information in sleep mode. Recent studies mainly focus on optimizing DRX parameters to manage the tradeoff between the energy consumption and communication latency. In this paper, we proposed a fuzzy-based power saving scheduling scheme for IoT over the LTE/LTE-Advanced networks to deal with the issues of the radio resource management and power consumption from the scheduling and resource allocation perspective. The proposed scheme considers not only individual IoT device’s real-time requirement but also the overall network performance. The simulation results show that our proposed scheme can meet the requirements of the DRX cycle and scheduling latency and can save about half of energy consumption for IoT devices compared to conventional approaches.

MILP Approach for Bilevel Transmission and Reactive Power Planning Considering Wind Curtailment

DEFF Research Database (Denmark)

Ugranli, Faruk; Karatepe, Engin; Nielsen, Arne Hejde

2017-01-01

In this study, two important planning problems in power systems that are transmission expansion and reactive power are formulated as a mixed-integer linear programming taking into account the bilevel structure due to the consideration of market clearing under several load-wind scenarios....... The objective of the proposed method is to minimize the installation cost of transmission lines, reactive power sources, and the annual operation costs of conventional generators corresponding to the curtailed wind energy while maintaining the reliable system operation. Lower level problems of the bilevel...... structure are designated for the market clearing which is formulated by using the linearized optimal power flow equations. In order to obtain mixed-integer linear programming formulation, the so-called lower level problems are represented by using primal-dual formulation. By using the proposed method, power...

Reactive power influence on the thermal cycling of multi-MW wind power inverter

DEFF Research Database (Denmark)

Ma, Ke; Liserre, Marco; Blaabjerg, Frede

2012-01-01

converter system are first presented at different wind speeds. Furthermore, the interaction between paralleled converter systems in a wind park is also considered and analyzed. By controlling the reactive power circulated among paralleled converters, a new concept is then proposed to stabilize the thermal...

Review of reactive power dispatch strategies for loss minimization in a DFIG-based wind farm

DEFF Research Database (Denmark)

Zhang, Baohua; Hu, Weihao; Hou, Peng

2017-01-01

power control strategies are investigated. All of the combined strategies are formulated based on the comprehensive loss models of WFs, including the loss models of DFIGs, converters, filters, transformers, and cables of the collection system. Optimization problems are solved by a Modified Particle......This paper reviews and compares the performance of reactive power dispatch strategies for the loss minimization of Doubly Fed Induction Generator (DFIG)-based Wind Farms (WFs). Twelve possible combinations of three WF level reactive power dispatch strategies and fourWind Turbine (WT) level reactive...... Swarm Optimization (MPSO) algorithm. The effectiveness of these strategies is evaluated by simulations on a carefully designed WF under a series of cases with different wind speeds and reactive power requirements of the WF. The wind speed at each WT inside the WF is calculated using the Jensen wake...

The effect of reactive emotions expressed in response to another's anger on inferences of social power.

Science.gov (United States)

Hareli, Shlomo; David, Shlomo

2017-06-01

Social perception of emotions is influenced by the context in which it occurs. One such context is a social interaction involving an exchange of emotions. The way parties to the interaction are perceived is shaped by the combination of emotions exchanged. This idea was examined by assessing the extent to which expressions of anger toward a target-which, in isolation, are perceived as signals of high social power-are influenced by the target's emotional reaction to it (i.e., reactive emotions). Three studies show that the angry person was perceived as having a higher level of social power when this anger was responded by fear or sadness than when it was responded by neutrality or anger. Study 1 indicated that reactive emotions have a stronger effect on perceived social power when emotions were incongruent with gender stereotypes. Study 2 indicated that these effects are a result of these emotions serving as reactive emotions rather than a benchmark against which the angry person's power is assessed. Study 3 showed that reactive emotions affect perceived social power by serving as signals of the level to which the high social power suggested by the first person's expression is confirmed by its target. Comparing effects of reactive emotions to anger with reactive emotions to sadness, showed that perceived social power of the expresser is determined by the nature of the expression, with some adjustment caused by the reactive emotions. This underscores the importance of social interaction as a context for the social perception of emotions. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Design and Optimisation of a Simple Filter Group for Reactive Power Distribution

Directory of Open Access Journals (Sweden)

Ryszard Klempka

2016-01-01

Full Text Available Basic methods are presented to design a simple filter group and a method of shaping the resultant of the filter group’s impedance characteristics (distribution of the characteristics’ extremes and then project equations were transformed into a uniform, common form that addresses issues of the reactive power distribution between component filters. The analysis also takes into account the filters’ detuning from the reduced harmonics and quality factors of passive elements. Another important factor of the analysis considered was the power grid equivalent impedance affecting the filtration effectiveness. A criterion for the filter group’s filtration effectiveness evaluation was proposed and optimisation was completed for the reactive power distribution between separate filters in the function of the power grid’s equivalent inductance.

A Downlink and Uplink Alignment Scheme for Power Saving in IEEE 802.16 Protocol

Directory of Open Access Journals (Sweden)

Jenhui Chen

2014-01-01

Full Text Available This study shows the problem of power saving mechanism (PSM that sleep intervals of uplink (UL connections do not synchronize with sleep intervals of downlink (DL connections. That is, the energy of a mobile station (MS is not really saved if the DL connections are in the sleep mode while the UL connections are in normal mode, and vice versa. To avoid the asynchronism of power saving (PS between UL and DL connections, we invent a mechanism of DL connections regulating UL connections, called DL and UL Alignment (DUAL scheme, to improve the energy efficiency for PS. Considering that the buffer size of MS is limited, DUAL uses the mean packet arrival rate of UL λu and a relatively safe threshold of buffer size QT as the parameters to estimate the maximum allowable waiting time to align the UL with the DL connections. To analyze the performance of DUAL, a system model of PS is proposed to evaluate the performance of DUAL under different conditions. The correctness of performance analysis of DUAL is validated by using simulation with realistic parameters. Numerical experiments show that DUAL improves the energy conservation significantly when UL traffic is greater than DL traffic.

Flapping wing flight can save aerodynamic power compared to steady flight.

Science.gov (United States)

Pesavento, Umberto; Wang, Z Jane

2009-09-11

Flapping flight is more maneuverable than steady flight. It is debated whether this advantage is necessarily accompanied by a trade-off in the flight efficiency. Here we ask if any flapping motion exists that is aerodynamically more efficient than the optimal steady motion. We solve the Navier-Stokes equation governing the fluid dynamics around a 2D flapping wing, and determine the minimal aerodynamic power needed to support a specified weight. While most flapping wing motions are more costly than the optimal steady wing motion, we find that optimized flapping wing motions can save up to 27% of the aerodynamic power required by the optimal steady flight. We explain the cause of this energetic advantage.

How much electricity can we save by using direct current circuits in homes? Understanding the potential for electricity savings and assessing feasibility of a transition towards DC powered buildings

International Nuclear Information System (INIS)

Glasgo, Brock; Azevedo, Inês Lima; Hendrickson, Chris

2016-01-01

Highlights: • DC distribution systems are analyzed using monitored appliance and solar PV data. • DC-distributed PV energy generates savings under real-world load and solar profiles. • Savings from direct-DC are generally not cost-effective in current markets. • Non-technical hurdles remain before DC can be widely adopted in US homes. - Abstract: Advances in semiconductor-based power electronics and growing direct current loads in buildings have led researchers to reconsider whether buildings should be wired with DC circuits to reduce power conversions and facilitate a transition to efficient DC appliances. The feasibility, energy savings, and economics of such systems have been assessed and proven in data centers and commercial buildings, but the outcomes are still uncertain for the residential sector. In this work, we assess the technical and economic feasibility of DC circuits using data for 120 traditionally-wired AC homes in Austin, Texas to understand the effect of highly variable demand profiles on DC-powered residences, using appliance-level use and solar generation data, and performing a Monte Carlo simulation to quantify costs and benefits. Results show site energy savings between 9% and 20% when solar PV is distributed to all home appliances. When battery storage for excess solar energy is considered, these savings increase to 14–25%. At present DC equipment prices, converting all equipment to DC causes levelized annual costs of electricity to homeowners to roughly double. However, by converting only homes’ air conditioning condensing units to DC, the costs of direct-DC are greatly reduced and home site energy savings of 7–16% are generated. In addition to quantifying savings, we find major nontechnical barriers to implementing direct-DC in homes. These include a lack of standards for such systems, a relatively small market for DC appliances and components, utility programs designed for AC power, and a workforce unfamiliar with DC

Sensitivity analysis of power excursion in RSG-GAS reactor due to reactivity insertion

International Nuclear Information System (INIS)

Pinem, Surian; Sembiring, Tagor Malem

2002-01-01

Reactor kinetics has a very important role in reactor operation safety and nuclear reactor control. One of the important aspects in reactor kinetics is power behavior as function of time due to chain reaction in the core. The calculation was performed using kinetic equation and feedback reactivity and evaluated using static power coefficient. Analysis was performed for oxide 250 g, silicide 250 g and silicide 300 g fuel elements with insertion of positive reactivity, negative reactivity and reactivity close to delay neutron fraction. The calculation of power excursion sensitivity showed that the insertion of 0,5 % Δk/k, in the fuel element of silicide 300 g is bigger 5 % than the one of oxide 250 g or silicide 250 g. If inserted by - 1,2 % Δk/k, there is no change among three fuel elements. Therefore, in kinetic point of view, it is showed there is no significant influence in the RSG-GAS reactor operation safety is the current core of oxide 250 g is converted to silicide 250 g or to silicide 300 g

Consensus-based Distributed Control for Accurate Reactive, Harmonic and Imbalance Power Sharing in Microgrids

DEFF Research Database (Denmark)

Zhou, Jianguo; Kim, Sunghyok; Zhang, Huaguang

2018-01-01

This paper investigates the issue of accurate reactive, harmonic and imbalance power sharing in a microgrid. Harmonic and imbalance droop controllers are developed to proportionally share the harmonic power and the imbalance power among distributed generation (DG) units and improve the voltage...... voltage. With the proposed methods, the microgrid system reliability and flexibility can be enhanced and the knowledge of the line impedance is not required. And the reactive, harmonic and imbalance power can be proportionally shared among the DG units. Moreover, the quality of the voltage at PCC can...

Use of reactivity constraints for the automatic control of reactor power

International Nuclear Information System (INIS)

Bernard, J.A.; Lanning, D.D.; Ray, A.

1985-01-01

A theoretical framework for the automatic control of reactor power has been developed and experimentally evaluated on the 5 MWt Research Reactor that is operated by the Massachusetts Institute of Technology. The controller functions by restricting the net reactivity so that it is always possible to make the reactor period infinite at the desired termination point of a transient by reversing the direction of motion of whatever control mechanism is associated with the controller. This capability is formally designated as ''feasibility of control''. It has been shown experimentally that maintenance of feasibility of control is a sufficient condition for the automatic control of reactor power. This research should be of value in the design of closed-loop controllers, in the creation of reactivity displays, in the provision of guidance to operators regarding the timing of reactivity changes, and as an experimental envelope within which alternate control strategies can be evaluated

Reactive power and voltage control strategy based on dynamic and adaptive segment for DG inverter

Science.gov (United States)

Zhai, Jianwei; Lin, Xiaoming; Zhang, Yongjun

2018-03-01

The inverter of distributed generation (DG) can support reactive power to help solve the problem of out-of-limit voltage in active distribution network (ADN). Therefore, a reactive voltage control strategy based on dynamic and adaptive segment for DG inverter is put forward to actively control voltage in this paper. The proposed strategy adjusts the segmented voltage threshold of Q(U) droop curve dynamically and adaptively according to the voltage of grid-connected point and the power direction of adjacent downstream line. And then the reactive power reference of DG inverter can be got through modified Q(U) control strategy. The reactive power of inverter is controlled to trace the reference value. The proposed control strategy can not only control the local voltage of grid-connected point but also help to maintain voltage within qualified range considering the terminal voltage of distribution feeder and the reactive support for adjacent downstream DG. The scheme using the proposed strategy is compared with the scheme without the reactive support of DG inverter and the scheme using the Q(U) control strategy with constant segmented voltage threshold. The simulation results suggest that the proposed method has a significant improvement on solving the problem of out-of-limit voltage, restraining voltage variation and improving voltage quality.

Efficient use of power. Directory for private households to save power without renunciation of comfort; Strom effizient nutzen. Wegweiser fuer Privathaushalte zur wirtschaftlichen Stromeinsparung ohne Komfortverzicht

Energy Technology Data Exchange (ETDEWEB)

NONE

2011-07-01

The contribution under consideration is a guide for private households for an economically efficient conservation of electricity without renunciation of comfort. At first, reasons for saving electricity are presented. The approach to reduce power consumption consists of an inventory of electricity consumers, establishment of measures to save electricity as well as a selection of suitable measures. Tables are presented for the determination of the power consumption and costs for electricity in the actual and target state as well as for the determination of the economic efficiency.

Coordinated Volt/Var Control in Distribution Systems with Distributed Generations Based on Joint Active and Reactive Powers Dispatch

Directory of Open Access Journals (Sweden)

Abouzar Samimi

2016-01-01

Full Text Available One of the most significant control schemes in optimal operation of distribution networks is Volt/Var control (VVC. Owing to the radial structure of distribution systems and distribution lines with a small X/R ratio, the active power scheduling affects the VVC issue. A Distribution System Operator (DSO procures its active and reactive power requirements from Distributed Generations (DGs along with the wholesale electricity market. This paper proposes a new operational scheduling method based on a joint day-ahead active/reactive power market at the distribution level. To this end, based on the capability curve, a generic reactive power cost model for DGs is developed. The joint active/reactive power dispatch model presented in this paper motivates DGs to actively participate not only in the energy markets, but also in the VVC scheme through a competitive market. The proposed method which will be performed in an offline manner aims to optimally determine (i the scheduled active and reactive power values of generation units; (ii reactive power values of switched capacitor banks; and (iii tap positions of transformers for the next day. The joint active/reactive power dispatch model for daily VVC is modeled in GAMS and solved with the DICOPT solver. Finally, the plausibility of the proposed scheduling framework is examined on a typical 22-bus distribution test network over a 24-h period.

Energy-saving and emission-abatement potential of Chinese coal-fired power enterprise: A non-parametric analysis

International Nuclear Information System (INIS)

Wei, Chu; Löschel, Andreas; Liu, Bing

2015-01-01

In the context of soaring demand for electricity, mitigating and controlling greenhouse gas emissions is a great challenge for China's power sector. Increasing attention has been placed on the evaluation of energy efficiency and CO 2 abatement potential in the power sector. However, studies at the micro-level are relatively rare due to serious data limitations. This study uses the 2004 and 2008 Census data of Zhejiang province to construct a non-parametric frontier in order to assess the abatement space of energy and associated CO 2 emission from China's coal-fired power enterprises. A Weighted Russell Directional Distance Function (WRDDF) is applied to construct an energy-saving potential index and a CO 2 emission-abatement potential index. Both indicators depict the inefficiency level in terms of energy utilization and CO 2 emissions of electric power plants. Our results show a substantial variation of energy-saving potential and CO 2 abatement potential among enterprises. We find that large power enterprises are less efficient in 2004, but become more efficient than smaller enterprises in 2008. State-owned enterprises (SOE) are not significantly different in 2008 from 2004, but perform better than their non-SOE counterparts in 2008. This change in performance for large enterprises and SOE might be driven by the “top-1000 Enterprise Energy Conservation Action” that was implemented in 2006. - Highlights: • Energy-saving potential and CO 2 abatement-potential for Chinese power enterprise are evaluated. • The potential to curb energy and emission shows great variation and dynamic changes. • Large enterprise is less efficient than small enterprise in 2004, but more efficient in 2008. • The state-owned enterprise performs better than non-state-owned enterprise in 2008

Economic-environmental active and reactive power scheduling of modern distribution systems in presence of wind generations: A distribution market-based approach

International Nuclear Information System (INIS)

Samimi, Abouzar; Kazemi, Ahad; Siano, Pierluigi

2015-01-01

Highlights: • A new market-based approach is proposed to schedule active and reactive powers. • Multi-component reactive power bidding structures for DERs is introduced. • A new economical/environmental operational scheduling method is proposed. • At distribution level, a reactive power market is developed in presence of DERs. - Abstract: Distribution System Operator (DSO) is responsible for active and reactive power scheduling in a distribution system. DSO purchases its active and reactive power requirements from Distributed Energy Resources (DERs) as well as the wholesale electricity market. In this paper, a new economical/environmental operational scheduling method based on sequential day-ahead active and reactive power markets at distribution level is proposed to dispatch active and reactive powers in distribution systems with high penetration of DERs. In the proposed model, after day-ahead active power market was cleared the participants submit their reactive power bids and then the reactive power market will be settled. At distribution level, developing a Var market, in which DERs like synchronous machine-based Distributed Generation (DG) units and Wind Turbines (WTs) could offer their reactive power prices, DERs are motivated to actively participate in the Volt/VAr Control (VVC) problem. To achieve this purpose, based on the capability curves of considered DERs, innovative multi-component reactive power bidding structures for DERs are introduced. Moreover, the effect of reactive power market clearing on the active power scheduling is explicitly considered into the proposed model by rescheduling of active power by usage of energy-balance service bids. On the other hand, environmental concerns that arise from the operation of fossil fuel fired electric generators are included in the proposed model by employing CO_2 emission penalty cost. The suggested reactive power market is cleared through a mixed-integer nonlinear optimization program. The

Electric Power Saving Awareness System at School Using ICT

Directory of Open Access Journals (Sweden)

Kuzume Koichi

2016-01-01

Full Text Available Nowadays, education on energy saving at schools attracts attention to reduce energy consumption. In this paper we proposed a novel system to promote energy conservation activity at schools using a sensor network. The system consisted of a wall-type clock embedded with several kinds of sensors for temperature and light in the classroom, and wireless devices to connect to a cloud computer network. The system had the following superiorities: offered various services for energy conservation activity, needless of CT (Current Transformer sensor, low price, ease of installation and extension, and visualization of power consumption in conjunction with school timetable in real time. We presented the system and a user study conducted to evaluate its usefulness.

Investigations of heat-hydraulic noises in the equipment for creation of power-saving technologies

International Nuclear Information System (INIS)

Proskuryakov, K.N.

2000-01-01

The results of experimental and theoretical studies on the parameters of vibroacoustic signals, originating in the TPP and NPP thermal energy equipment, are presented. The methods for calculation and identification of the heat-hydraulic perturbation sources, intended for improving the means of early diagnostics of anomalies in the technological process, forecasting their development, increasing the maintenance work efficiency and operational safety, as well as for creating power-saving technologies in the power engineering, are developed [ru

Calculation of research reactor RA power at uncontrolled reactivity changes

International Nuclear Information System (INIS)

Cupac, S.

1978-01-01

The safety analysis of research reactor RA involves also the calculation of reactor power at uncontrolled reactivity changes. The corresponding computer code, based on Point Kinetics Model has been made. The short review of method applied for solving kinetic equations is given and several examples illustrating the reactor behaviour at various reactivity changes are presented. The results already obtained are giving rather rough picture of reactor behaviour in considered situations. This is the consequence of using simplified feed back and reactor cooling models, as well as temperature reactivity coefficients, which do not correspond to the actual reactor RA structure (which is now only partly fulfilled with 80% enriched uranium fuel). (author) [sr

Thermal Performance and Reliability Analysis of Single-Phase PV Inverters with Reactive Power Injection Outside Feed-In Operating Hours

DEFF Research Database (Denmark)

Anurag, Anup; Yang, Yongheng; Blaabjerg, Frede

2015-01-01

Reactive power support by photovoltaic (PV) systems is of increasingly interest, when compared to the conventional reactive power compensation devices. PV inverters can exchange reactive power with the utility grid in a decentralized manner even outside feed-in operation, especially at nights when...... there is no solar irradiance. However, reactive power injection causes additional power losses in the switching components leading to a temperature rise in the devices. Thus, this paper analyses the impact of reactive power injection by PV inverters outside feed-in operation on the thermal performance...... of their power switching components. A thermal analysis based on the mission profile (i.e., solar irradiance and ambient temperature) has been incorporated, so as to determine the additional temperature rise in the components induced by the operation outside feed-in hours. An analytical lifetime model has been...

Wolf Search Algorithm for Solving Optimal Reactive Power Dispatch Problem

Directory of Open Access Journals (Sweden)

Kanagasabai Lenin

2015-03-01

Full Text Available This paper presents a new bio-inspired heuristic optimization algorithm called the Wolf Search Algorithm (WSA for solving the multi-objective reactive power dispatch problem. Wolf Search algorithm is a new bio – inspired heuristic algorithm which based on wolf preying behaviour. The way wolves search for food and survive by avoiding their enemies has been imitated to formulate the algorithm for solving the reactive power dispatches. And the speciality  of wolf is  possessing  both individual local searching ability and autonomous flocking movement and this special property has been utilized to formulate the search algorithm .The proposed (WSA algorithm has been tested on standard IEEE 30 bus test system and simulation results shows clearly about the good performance of the proposed algorithm .

Public-opinion poll on energy saving

International Nuclear Information System (INIS)

1982-01-01

A public-opinion poll was carried out on energy saving from November 26 to December 2, 1981, across the country. The number of persons participated in the survey was 5,000, whose age was 20 and above. The recovery ratio was 4,007 persons (80.1 %). The results of the survey and also the question-answer form are given with respective percentages. The questions were in the following three categories: (1) cognizance of energy saving - space-heating temperature, energy saving conscience use of private cars, purchase of highenergy consumption appliances; (2) energy for future - energy consumption, energy consumption trend, new types of energy, main sources of power generation, nuclear power in the overall electric power, apprehension toward nuclear power plants, safety measures in nuclear power plants; (3) governmental energy policy measures. (J.P.N.)

Modified artificial bee colony algorithm for reactive power optimization

Science.gov (United States)

Sulaiman, Noorazliza; Mohamad-Saleh, Junita; Abro, Abdul Ghani

2015-05-01

Bio-inspired algorithms (BIAs) implemented to solve various optimization problems have shown promising results which are very important in this severely complex real-world. Artificial Bee Colony (ABC) algorithm, a kind of BIAs has demonstrated tremendous results as compared to other optimization algorithms. This paper presents a new modified ABC algorithm referred to as JA-ABC3 with the aim to enhance convergence speed and avoid premature convergence. The proposed algorithm has been simulated on ten commonly used benchmarks functions. Its performance has also been compared with other existing ABC variants. To justify its robust applicability, the proposed algorithm has been tested to solve Reactive Power Optimization problem. The results have shown that the proposed algorithm has superior performance to other existing ABC variants e.g. GABC, BABC1, BABC2, BsfABC dan IABC in terms of convergence speed. Furthermore, the proposed algorithm has also demonstrated excellence performance in solving Reactive Power Optimization problem.

Multiagent voltage and reactive power control system

Directory of Open Access Journals (Sweden)

I. Arkhipov

2014-12-01

Full Text Available This paper is devoted to the research of multiagent voltage and reactive power control system development. The prototype of the system has been developed by R&D Center at FGC UES (Russia. The control system architecture is based on the innovative multiagent system theory application that leads to the achievement of several significant advantages (in comparison to traditional control systems implementation such as control system efficiency enhancement, control system survivability and cyber security.

Dynamic Power-Saving Method for Wi-Fi Direct Based IoT Networks Considering Variable-Bit-Rate Video Traffic.

Science.gov (United States)

Jin, Meihua; Jung, Ji-Young; Lee, Jung-Ryun

2016-10-12

With the arrival of the era of Internet of Things (IoT), Wi-Fi Direct is becoming an emerging wireless technology that allows one to communicate through a direct connection between the mobile devices anytime, anywhere. In Wi-Fi Direct-based IoT networks, all devices are categorized by group of owner (GO) and client. Since portability is emphasized in Wi-Fi Direct devices, it is essential to control the energy consumption of a device very efficiently. In order to avoid unnecessary power consumed by GO, Wi-Fi Direct standard defines two power-saving methods: Opportunistic and Notice of Absence (NoA) power-saving methods. In this paper, we suggest an algorithm to enhance the energy efficiency of Wi-Fi Direct power-saving, considering the characteristics of multimedia video traffic. Proposed algorithm utilizes the statistical distribution for the size of video frames and adjusts the lengths of awake intervals in a beacon interval dynamically. In addition, considering the inter-dependency among video frames, the proposed algorithm ensures that a video frame having high priority is transmitted with higher probability than other frames having low priority. Simulation results show that the proposed method outperforms the traditional NoA method in terms of average delay and energy efficiency.

Optimal Coordinated EV Charging with Reactive Power Support in Constrained Distribution Grids

Energy Technology Data Exchange (ETDEWEB)

Paudyal, Sumit; Ceylan, Oğuzhan; Bhattarai, Bishnu P.; Myers, Kurt S.

2017-07-01

Electric vehicle (EV) charging/discharging can take place in any P-Q quadrants, which means EVs could support reactive power to the grid while charging the battery. In controlled charging schemes, distribution system operator (DSO) coordinates with the charging of EV fleets to ensure grid’s operating constraints are not violated. In fact, this refers to DSO setting upper bounds on power limits for EV charging. In this work, we demonstrate that if EVs inject reactive power into the grid while charging, DSO could issue higher upper bounds on the active power limits for the EVs for the same set of grid constraints. We demonstrate the concept in an 33-node test feeder with 1,500 EVs. Case studies show that in constrained distribution grids in coordinated charging, average costs of EV charging could be reduced if the charging takes place in the fourth P-Q quadrant compared to charging with unity power factor.

Integrated Power Saving for Multiple Relays and UEs in LTE-TDD

OpenAIRE

Chun-Chuan Yang; Jeng-Yueng Chen; Yi-Ting Mai; Chen-Ming Yang

2017-01-01

In this paper, the design of integrated sleep scheduling for relay nodes and user equipments under a Donor eNB (DeNB) in the mode of Time Division Duplex (TDD) in LTE-A is presented. The idea of virtual time is proposed to deal with the discontinuous pattern of the available radio resource in TDD, and based on the estimation of the traffic load, three power saving schemes in the top-down strategy are presented. Associated mechanisms in each scheme including calculation of the virtual subframe...

Force analysis of magnetic bearings with power-saving controls

International Nuclear Information System (INIS)

Johnson, D.; Brown, G.V.; Inman, D.J.

1992-01-01

Most magnetic bearing control schemes use a bias current with a superimposed control current to linearize the relationship between the control current and the force it delivers. For most operating conditions, the existence of the bias current requires more power than alternative methods that do not use conventional bias. Two such methods are examined which diminish or eliminate bias current. In the typical bias control scheme it is found that for a harmonic control force command into a voltage limited transconductance amplifier, the desired force output is obtained only up to certain combinations of force amplitude and frequency. Above these values, the force amplitude is reduced and a phase lag occurs. The power saving alternative control schemes typically exhibit such deficiencies at even lower command frequencies and amplitudes. To assess the severity of these effects, a time history analysis of the force output is performed for the bias method and the alternative methods. Results of the analysis show that the alternative approaches may be viable. The various control methods examined were mathematically modeled using nondimensionalized variables to facilitate comparison of the various methods

A Fast Reactive Power Optimization in Distribution Network Based on Large Random Matrix Theory and Data Analysis

Directory of Open Access Journals (Sweden)

Wanxing Sheng

2016-05-01

Full Text Available In this paper, a reactive power optimization method based on historical data is investigated to solve the dynamic reactive power optimization problem in distribution network. In order to reflect the variation of loads, network loads are represented in a form of random matrix. Load similarity (LS is defined to measure the degree of similarity between the loads in different days and the calculation method of the load similarity of load random matrix (LRM is presented. By calculating the load similarity between the forecasting random matrix and the random matrix of historical load, the historical reactive power optimization dispatching scheme that most matches the forecasting load can be found for reactive power control usage. The differences of daily load curves between working days and weekends in different seasons are considered in the proposed method. The proposed method is tested on a standard 14 nodes distribution network with three different types of load. The computational result demonstrates that the proposed method for reactive power optimization is fast, feasible and effective in distribution network.

Comprehensive evaluation and study on energy saving and emission reduction of nuclear power based on the osculation value method

International Nuclear Information System (INIS)

Liu Zhihui; Wei Fangxin; Liu Xiaomin

2014-01-01

By means of osculation value method, several provinces are selected to study the energy saving and emission reduction effect of nuclear power from provincial range according to the statistic data in 2010. Theoretically, nuclear power effect is reducing the consumption of non-renewable energy such as coal and reducing the release of pollutants such as CO 2 . The result shows that the comprehensive evaluation of energy saving and emission reduction effect in Zhejiang and Jiangsu provinces are the best. In comparison, Guangdong province falls behind Hubei and Fujian provinces. Total consumption of coal per unit of GDP in Guangdong, Zhejiang, and Jiangsu provinces is apparently lower than that of Hebei, Shanxi, Liaoning, and Hubei provinces. However, total release of SO 2 and NOx, etc. is apparently reduced in provinces with nuclear power, compared with provinces without nuclear power. But total release of CO 2 from thermal power generation (coal) per unit of GDP is not apparently reduced in provinces with nuclear power than those without. (authors)

Computation, measurement and analysis of the reactivity-to-power-transfer-function for the sodium cooled nuclear power plant KNK I

International Nuclear Information System (INIS)

Hoppe, P.; Mitzel, F.

1977-02-01

The Reactivity-to-Power-Transfer-Function for the sodium cooled nuclear power plant KNK I (Kompakte Natriumgekuehlte Kernenergieanlage) has been measured and compared with theoretical results. The measurements have been performed with the help of pseudostochastic reactivity perturbations. The transfer function has been determined by computing the auto- and cross-power-spectral-densities for the reactivity- and neutron flux signals. The agreement between the experimental and theoretical transfer function could be improved by adjusting the reactivity coefficients. The applications of these measurements with respect to reactor diagnosis and malfunction detection are discussed. For this purpose the accuracy of the measured transfer function is of great importance. Therefore an extensive error analysis has been performed. It turned out, that the inherent instability of the reactor without control system and the feedback by the primary coolant system were the reasons for comparatively big systematical errors. The conditions have been derived under which these types of errors can be considerably reduced. The conclusions can also be applied to analogical measurements at fast sodium cooled reactors. Because of their inherent stability the systematical errors will be reduced. (orig.) [de

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.

Autonomous Active and Reactive Power Distribution Strategy in Islanded Microgrids

DEFF Research Database (Denmark)

Wu, Dan; Tang, Fen; Guerrero, Josep M.

2014-01-01

This paper proposes an autonomous active and reactive power distribution strategy that can be applied directly on current control mode (CCM) inverters, being compatible as well with conventional droop-controlled voltage control mode (VCM) converters. In a microgrid, since renewable energy sources...

An objective decision model of power grid environmental protection based on environmental influence index and energy-saving and emission-reducing index

Science.gov (United States)

Feng, Jun-shu; Jin, Yan-ming; Hao, Wei-hua

2017-01-01

Based on modelling the environmental influence index of power transmission and transformation project and energy-saving and emission-reducing index of source-grid-load of power system, this paper establishes an objective decision model of power grid environmental protection, with constraints of power grid environmental protection objectives being legal and economical, and considering both positive and negative influences of grid on the environmental in all-life grid cycle. This model can be used to guide the programming work of power grid environmental protection. A numerical simulation of Jiangsu province’s power grid environmental protection objective decision model has been operated, and the results shows that the maximum goal of energy-saving and emission-reducing benefits would be reached firstly as investment increasing, and then the minimum goal of environmental influence.

Opposition-Based Improved PSO for Optimal Reactive Power Dispatch and Voltage Control

Directory of Open Access Journals (Sweden)

Shengrang Cao

2015-01-01

Full Text Available An opposition-based improved particle swarm optimization algorithm (OIPSO is presented for solving multiobjective reactive power optimization problem. OIPSO uses the opposition learning to improve search efficiency, adopts inertia weight factors to balance global and local exploration, and takes crossover and mutation and neighborhood model strategy to enhance population diversity. Then, a new multiobjective model is built, which includes system network loss, voltage dissatisfaction, and switching operation. Based on the market cost prices, objective functions are converted to least-cost model. In modeling process, switching operation cost is described according to the life cycle cost of transformer, and voltage dissatisfaction penalty is developed considering different voltage quality requirements of customers. The experiment is done on the new mathematical model. Through the simulation of IEEE 30-, 118-bus power systems, the results prove that OIPSO is more efficient to solve reactive power optimization problems and the model is more accurate to reflect the real power system operation.

Guidelines for Distribution System Operators on Reactive Power Provision by Electric Vehicles in Low Voltage Grids

DEFF Research Database (Denmark)

Zecchino, Antonio; Marinelli, Mattia; Træholt, Chresten

2017-01-01

The increasing success of electric vehicles is bringing new technical challenges to power system operators. This work intends to provide guidelines for distribution system operators in terms of reactive power requirements when evaluating and authorizing electric vehicles supply equipment with fast...... the amount of reactive power that an individual electric vehicle is expected to provide when connected to a low voltage feeder, in order to benefit of the desired voltage rise effect in comparison to the case of unitary power factor....

Distributed multi-agent scheme for reactive power management with renewable energy

International Nuclear Information System (INIS)

Rahman, M.S.; Mahmud, M.A.; Pota, H.R.; Hossain, M.J.

2014-01-01

Highlights: • A distributed multi-agent scheme is proposed to enhance the dynamic voltage stability. • A control agent is designed where control actions are performed through PI controller. • Proposed scheme is compared with the conventional approach with DSTATCOM. • Proposed scheme adapts the capability of estimation and control under various operating conditions. - Abstract: This paper presents a new distributed multi-agent scheme for reactive power management in smart coordinated distribution networks with renewable energy sources (RESs) to enhance the dynamic voltage stability, which is mainly based on controlling distributed static synchronous compensators (DSTATCOMs). The proposed control scheme is incorporated in a multi-agent framework where the intelligent agents simultaneously coordinate with each other and represent various physical models to provide information and energy flow among different physical processes. The reactive power is estimated from the topology of distribution networks and with this information, necessary control actions are performed through the proposed proportional integral (PI) controller. The performance of the proposed scheme is evaluated on a 8-bus distribution network under various operating conditions. The performance of the proposed scheme is validated through simulation results and these results are compared to that of conventional PI-based DSTATCOM control scheme. From simulation results, it is found that the distributed MAS provides excellence performance for improving voltage profiles by managing reactive power in a smarter way

Energy-saving modification on outdoor lighting in the nuclear power plant

International Nuclear Information System (INIS)

Yao Bo

2010-01-01

The outdoor lighting in the nuclear power plant don't automatically shut down,and cause lights to be long-light. It is proposed to install light-control switches in the electric circuit in order to achieve automatic control. The original outdoor lighting circuit uses the circuit breaker for over-current protection and short circuit fault protection, and use remote circuit breaker to manually operate the lamp on and off.Each circuit branch installs a light-control switch, and set the threshold of 100 lux for the light-control switch. When the natural illumination meet the minimum illumination requirement (> 100lux), the lights shut down the power.When natural illumination doesn't meet the lighting requirement (<100lux), the lighting automatically close.After the modification, it is resolved the outdoor lighting easily becoming a long light,and save energy. (authors)

Fast Control Channel Decoding for LTE UE Power Saving

DEFF Research Database (Denmark)

Lauridsen, Mads; Jensen, Anders Riis; Mogensen, Preben

2012-01-01

in the current TTI. The cost is that some reference signals are not received leading to a degraded channel estimate. Calculations show that this causes an SINR degradation of approximately 0.5 dB, which will result in maximum 4 % throughput loss. Comparing this with energy saving potentials of 5 %-25...... % it is concluded that the FCCD method is a valuable aid to prolong LTE phones' battery lifetime. The results are generated using a two state Markov chain model to simulate traffic and scheduling, and verified mathematically. The work also includes an examination of various data traffic types' on/off relation...... and an evaluation of how the relation affects power consumption. The FCCD method can complement DRX sleep mode since it is applicable when the signal is too aperiodic or fast switching for DRX....

Modelling energy savings in the Danish building sector combined with internalisation of health related externalities in a heat and power system optimisation model

International Nuclear Information System (INIS)

Zvingilaite, Erika

2013-01-01

A substantial untapped energy saving potential rests in the building sector and is expected to play an important role in achieving reduction of environmental impacts of energy. In order to utilise this potential, effective policy measures need to be adopted to remove the existing barriers and create incentives. For that purpose, the cost effective energy saving options together with an optimal level of savings and expected environmental benefits have to be identified. The paper reports on a study that analyses these questions by including heat-saving measures in buildings into an energy system optimisation model of the Danish heat and power sector. The achieved optimal level of heat savings reaches 11% of projected heat demand in 2025 under the model assumptions. Moreover, the analysis reveals the importance of considering energy conservation options in a system wide perspective. Furthermore, the results suggest that changes in the energy generation sector are the prime driver behind the reduction of environmental externalities of energy. Heat savings in buildings play only a small role under model assumptions. - Highlights: ► Heat savings in buildings are analysed together with a heat and power system. ► Heat savings compete with electricity to heat technologies, mainly heat pumps. ► Cost effective heat-savings bring small decrease in health impacts and CO 2 emissions. ► Cost-effectiveness of heat savings depends on the marginal heat generation technology

Reactive Power Injection Strategies for Single-Phase Photovoltaic Systems Considering Grid Requirements

DEFF Research Database (Denmark)

Yang, Yongheng; Wang, Huai; Blaabjerg, Frede

2014-01-01

.g. Germany and Italy. Those advanced features can be provided by next generation PV systems, and will be enhanced in the future to ensure an even efficient and reliable utilization of PV systems. In light of this, Reactive Power Injection (RPI) strategies for single-phase PV systems are explored...... in this paper. The RPI possibilities are: a) constant average active power control, b) constant active current control, c) constant peak current control and d) thermal optimized control strategy. All those strategies comply with the currently active grid codes, but are with different objectives. The proposed...... RPI strategies are demonstrated firstly by simulations and also tested experimentally on a 1 kW singe-phase grid-connected system in LVRT operation mode. Those results show the effectiveness and feasibilities of the proposed strategies with reactive power control during LVRT operation. The design...

Remuneration of the reactive power in the Argentinean supply market; Remuneracao da potencia reativa no mercado de suprimento argentino

Energy Technology Data Exchange (ETDEWEB)

Kerszberg, Ernesto M; Dravnovsky, Mario Carlos [Administradora del Mercado Mayorista Eletrico S.A. (Argentina)

1996-05-01

This work presents the standards and legislation about power reactive consumption by involved agents in the market electric power supply. It discusses how to remunerate this reactive and the compromises among the actors of the power electric system

Long term storage effects of irradiated fuel elements on power distribution and reactivity

Energy Technology Data Exchange (ETDEWEB)

Ponzoni Filho, P.; Sato, Sadakatu; Santos, Teresinha Ipojuca Cardoso T.I.C.; Fernandes Vanderlei Borba [FURNAS, Rio de Janeiro, RJ (Brazil); Fetterman, R.J. [Westinghouse Electric Corp., Pittsburgh, PA (United States)

1995-12-31

The ALPHA/PHOENIX-P/ANC (APA) code package was used to calculate the pin by pin power distribution and reactivity for Angra 1 Power Plant, Cycle 5. The Angra 1 Cycle 5 core was loaded with several irradiated fuel elements which were stored in the Spent Fuel Pool (SFP) for more than 8 years. Generally, neutronic codes take into account the buildup and depletion of just a few key fission, products such as Sm-149. In this paper it is shown that the buildup effects of other fission products must be considered for fuel which has been out of the core for significant periods of time. Impacts of these other fission products can change core reactivity and power distribution. (author). 3 refs, 4 figs, 4 tabs.

Long term storage effects of irradiated fuel elements on power distribution and reactivity

International Nuclear Information System (INIS)

Ponzoni Filho, P.; Sato, Sadakatu; Santos, Teresinha Ipojuca Cardoso T.I.C.; Fernandes Vanderlei Borba; Fetterman, R.J.

1995-01-01

The ALPHA/PHOENIX-P/ANC (APA) code package was used to calculate the pin by pin power distribution and reactivity for Angra 1 Power Plant, Cycle 5. The Angra 1 Cycle 5 core was loaded with several irradiated fuel elements which were stored in the Spent Fuel Pool (SFP) for more than 8 years. Generally, neutronic codes take into account the buildup and depletion of just a few key fission, products such as Sm-149. In this paper it is shown that the buildup effects of other fission products must be considered for fuel which has been out of the core for significant periods of time. Impacts of these other fission products can change core reactivity and power distribution. (author). 3 refs, 4 figs, 4 tabs

Acquiring energy savings in manufactured housing

International Nuclear Information System (INIS)

Davey, D.

1993-01-01

In 1991, the Northwest utilities faced a complex situation. They needed new sources of electrical power to avoid future deficits. A significant block of energy savings was available in the manufactured housing sector in the form of energy savings from increased insulation to new manufactured homes. The manufacturers were interested in saving the electricity in the homes, but would only deal with the utility sector as a whole. Half of the homes targeted were sited in investor-owned utility (IOU) service territories, and half in the public sector made up of utilities that purchased some or all of their electricity from the Bonneville Power Administration. Utilities agreed to acquire energy from manufacturers In the form of thermal efficiency measures specified by the Bonneville Power Administration. The program that resulted from over one year of negotiations was called the Manufactured Housing Acquisition Program, or MAP. Manufacturers, the utilities, State Energy Offices, the Northwest Power Planning Council and Bonneville all worked closely and with tenacity to build the program that went into effect on April 1, 1992, and should save the region between 7 and 9 megawatts, enough energy to supply 11,000 homes in the Northwest

Change in CANDU-6 reactivity following a power reduction at low PHT purity

International Nuclear Information System (INIS)

Whitlock, J.J.; Soulard, M.R.; Baudouin, A.

1995-01-01

The reactivity effect of a power reduction in CANDU-6 is examined using a three-dimensional, steady-state, coupled neutronics/thermalhydraulics methodology, starting from a global irradiation distribution matched to site data. The power reduction is sufficient to suppress coolant boiling in the fuel channels, and thus the significant parameters affecting reactivity are an increase in coolant density and a decrease in fuel temperature. These individual components are estimated using infinite-lattice-cell methodology. The effect of using newer methodology, particularly for the thermalhydraulic analysis, is examined by comparison with previous simulations. (author). 10 refs., 7 tabs., 1 fig

Power load leveling and energy saving measures for office buildings. Power load leveling and energy saving technology for the new building of the Kobe branch of the Kansai Electric Power Co., and its effect; Office biru no denryoku fuka heijunka sho energy hosaku. Kobe shiten shinshaoku ni okeru denryoku fuka heijunka sho energy gijutsu to sono koka

Energy Technology Data Exchange (ETDEWEB)

Tsuchiyama, M. [Kansai Electric Power Co. Inc., Osaka (Japan)

1999-06-10

This paper presents power load leveling and energy saving measures for heat source, air conditioning and lighting of the new Kobe branch building. The low-temperature hot-air system adopts an ice storage system, and reduces blowing power by 12 degreesC blowing in place of normal 16 degreesC blowing, and an initial cost by duct size reduction. The continuous air conditioning system levels an initial peak load of air conditioning as compared with normal air conditioning only for working hours for buildings with large heat capacity. In addition, as power load leveling measures for the whole building, the complete heat storage system using an underground internal melting type ice storage tank is adopted. Energy saving for lighting is achieved with a dimming lighting controlling its lighting output by inverter. The following effects are expected by these new technologies: Load leveling effect of 30%, energy saving effect of 20.2% and CO{sub 2} reduction effect of 24.1%. (NEDO)

A Location Selection Policy of Live Virtual Machine Migration for Power Saving and Load Balancing

Directory of Open Access Journals (Sweden)

Jia Zhao

2013-01-01

Full Text Available Green cloud data center has become a research hotspot of virtualized cloud computing architecture. And load balancing has also been one of the most important goals in cloud data centers. Since live virtual machine (VM migration technology is widely used and studied in cloud computing, we have focused on location selection (migration policy of live VM migration for power saving and load balancing. We propose a novel approach MOGA-LS, which is a heuristic and self-adaptive multiobjective optimization algorithm based on the improved genetic algorithm (GA. This paper has presented the specific design and implementation of MOGA-LS such as the design of the genetic operators, fitness values, and elitism. We have introduced the Pareto dominance theory and the simulated annealing (SA idea into MOGA-LS and have presented the specific process to get the final solution, and thus, the whole approach achieves a long-term efficient optimization for power saving and load balancing. The experimental results demonstrate that MOGA-LS evidently reduces the total incremental power consumption and better protects the performance of VM migration and achieves the balancing of system load compared with the existing research. It makes the result of live VM migration more high-effective and meaningful.

A location selection policy of live virtual machine migration for power saving and load balancing.

Science.gov (United States)

Zhao, Jia; Ding, Yan; Xu, Gaochao; Hu, Liang; Dong, Yushuang; Fu, Xiaodong

2013-01-01

Green cloud data center has become a research hotspot of virtualized cloud computing architecture. And load balancing has also been one of the most important goals in cloud data centers. Since live virtual machine (VM) migration technology is widely used and studied in cloud computing, we have focused on location selection (migration policy) of live VM migration for power saving and load balancing. We propose a novel approach MOGA-LS, which is a heuristic and self-adaptive multiobjective optimization algorithm based on the improved genetic algorithm (GA). This paper has presented the specific design and implementation of MOGA-LS such as the design of the genetic operators, fitness values, and elitism. We have introduced the Pareto dominance theory and the simulated annealing (SA) idea into MOGA-LS and have presented the specific process to get the final solution, and thus, the whole approach achieves a long-term efficient optimization for power saving and load balancing. The experimental results demonstrate that MOGA-LS evidently reduces the total incremental power consumption and better protects the performance of VM migration and achieves the balancing of system load compared with the existing research. It makes the result of live VM migration more high-effective and meaningful.

77 FR 21555 - Reactive Power Resources; Supplemental Notice of Technical Conference

Science.gov (United States)

2012-04-10

.... This panel will discuss: Methods used to determine the reactive power requirements for a transmission... Jenkins, Director--Utility Interconnection, First Solar Kris Zadlo, Vice President, Invenergy Richard..., Director--Utility Interconnection, First Solar Michael Jacobs, Director Market and Regulatory Policy...

Reactive power generation in high speed induction machines by continuously occurring space-transients

Science.gov (United States)

Laithwaite, E. R.; Kuznetsov, S. B.

1980-09-01

A new technique of continuously generating reactive power from the stator of a brushless induction machine is conceived and tested on a 10-kw linear machine and on 35 and 150 rotary cage motors. An auxiliary magnetic wave traveling at rotor speed is artificially created by the space-transient attributable to the asymmetrical stator winding. At least two distinct windings of different pole-pitch must be incorporated. This rotor wave drifts in and out of phase repeatedly with the stator MMF wave proper and the resulting modulation of the airgap flux is used to generate reactive VA apart from that required for magnetization or leakage flux. The VAR generation effect increases with machine size, and leading power factor operation of the entire machine is viable for large industrial motors and power system induction generators.

A New Approach to Optimal Allocation of Reactive Power Ancillary Service in Distribution Systems in the Presence of Distributed Energy Resources

Directory of Open Access Journals (Sweden)

Abouzar Samimi

2015-11-01

Full Text Available One of the most important Distribution System Operators (DSO schemes addresses the Volt/Var control (VVC problem. Developing a cost-based reactive power dispatch model for distribution systems, in which the reactive powers are appropriately priced, can motivate Distributed Energy Resources (DERs to participate actively in VVC. In this paper, new reactive power cost models for DERs, including synchronous machine-based DGs and wind turbines (WTs, are formulated based on their capability curves. To address VVC in the context of competitive electricity markets in distribution systems, first, in a day-ahead active power market, the initial active power dispatch of generation units is estimated considering environmental and economic aspects. Based on the results of the initial active power dispatch, the proposed VVC model is executed to optimally allocate reactive power support among all providers. Another novelty of this paper lies in the pricing scheme that rewards transformers and capacitors for tap and step changing, respectively, while incorporating the reactive power dispatch model. A Benders decomposition algorithm is employed as a solution method to solve the proposed reactive power dispatch, which is a mixed integer non-linear programming (MINLP problem. Finally, a typical 22-bus distribution network is used to verify the efficiency of the proposed method.

Photovoltaic Hosting Capacity of Feeders with Reactive Power Control and Tap Changers

Energy Technology Data Exchange (ETDEWEB)

Ceylan, Oğuzhan; Paudyal, Sumit; Bhattarai, Bishnu P.; Myers, Kurt S.

2017-06-01

This paper proposes an algorithm to determine photovoltaic (PV) hosting capacity of power distribution networks as a function of number of PV injection nodes, reactive power support from the PVs, and the sub-station load tap changers (LTCs). In the proposed method, several minute by minute simulations are run based on randomly chosen PV injection nodes, daily PV output profiles, and daily load profiles from a pool of high-resolution realistic data set. The simulation setup is built using OpenDSS and MATLAB. The performance of the proposed method is investigated in the IEEE 123-node distribution feeder for multiple scenarios. The case studies are performed particularly for one, two, five and ten PV injection nodes, and looking at the maximum voltage deviations. Case studies show that the PV hosting capacity of the 123-node feeder greatly differs with the number of PV injection nodes. We have also observed that the PV hosting capacity increases with reactive power support and higher tap position of sub-station LTC.

Optimum Arrangement of Reactive Power Sources While Using Genetic Algori

Directory of Open Access Journals (Sweden)

A. M. Gashimov

2010-01-01

Full Text Available Reduction of total losses in distribution electricity supply network is considered as an important measure which serves for improvement of efficiency of electric power supply systems. This objective can be achieved by optimum distribution of reactive power sources in proper places of distribution electricity supply network. The proposed methodology is based on application of a genetic algorithm. Total expenses for installation of capacitor banks, their operation and also expenses related to electric power losses are considered as an efficiency function which is used for determination of places with optimum values of capacitor bank power. The methodology is the most efficient for selection of optimum places in the network where it is necessary to install capacitor banks with due account of their power control depending on a switched-on load value in the units.

Variable flow controls of closed system pumps for energy savings in maritime power systems

DEFF Research Database (Denmark)

Su, Chun-Lien; Liao, Chi-Hsiang; Chou, Tso-Chu

2016-01-01

and field tests of a practical auxiliary boiler feed water management system on a commercial vessel. It is proved that the proposed method can maintain constant water pressure for closed system pumps and provide an efficient way to measure energy savings and maintenance benefits. The results serve......Pumps are extensively used in maritime industries as marine vessels utilize a wide range of pumps and pumping techniques to transfer and distribute all types of air and fluids. The electrical energy consumed by the various motors accounts for about 70% of a vessel’s total power consumption......, and this presents a problem in unique marine environments. Such situations are especially conducive to energy-saving strategies using variable frequency drives (VFDs) in centrifugal load service. This paper presents the design and results of applying variable frequency constant pressure technology in closed system...

Neutron and thermo - hydraulic model of a reactivity transient in a nuclear power plant fuel element

International Nuclear Information System (INIS)

Oliva, Jose de Jesus Rivero

2012-01-01

A reactivity transient without reactor scram was modeled and calculated using analytical expressions for the space distributions of the temperature fields, combined with discrete numerical calculations for the time dependences of thermal power and temperatures. The transient analysis covered the time dependencies of reactivity, global thermal power, fuel heat flux and temperatures in fuel, cladding and cooling water. The model was implemented in Microsoft Office Excel, dividing the Excel file in several separated worksheets for input data, initial steady-state calculations, calculation of parameters non-depending on eigenvalues, eigenvalues determination, calculation of parameters depending on eigenvalues, transient calculation and graphical representation of intermediate and final results. The results show how the thermal power reaches a new equilibrium state due to the negative reactivity feedback derived from the fuel temperature increment. Nevertheless, the reactor mean power increases 40% during the first second and, in the hottest channel, the maximum fuel temperature goes to a significantly high value, slightly above 2100 deg C, after 8 seconds of transient. Consequently, the results confirm that certain degree of fuel damage could be expected in case of a reactor scram failure. Once the basic model has being established the scope of accidents for future analyses can be extended, modifying the nuclear power behavior (reactivity) during transient and the boundary conditions for coolant temperature. A more complex model is underway for an annular fuel element. (author)

Combination of AC Transmission Expansion Planning and Reactive Power Planning in the restructured power system

International Nuclear Information System (INIS)

Hooshmand, Rahmat-Allah; Hemmati, Reza; Parastegari, Moein

2012-01-01

Highlights: ► To overcome the disadvantages of DC model in Transmission Expansion Planning, AC model should be used. ► The Transmission Expansion Planning associated with Reactive Power Planning results in fewer new transmission lines. ► Electricity market concepts should be considered in Transmission Expansion Planning problem. ► Reliability aspects should be considered in Transmission Expansion Planning problem. ► Particle Swarm Optimization is a suitable optimization method to solve Transmission Expansion Planning problem. - Abstract: Transmission Expansion Planning (TEP) is an important issue in power system studies. It involves decisions on location and number of new transmission lines. Before deregulation of the power system, the goal of TEP problem was investment cost minimization. But in the restructured power system, nodal prices, congestion management, congestion surplus and so on, have been considered too. In this paper, an AC model of TEP problem (AC-TEP) associated with Reactive Power Planning (RPP) is presented. The goals of the proposed planning problem are to minimize investment cost and maximize social benefit at the same time. In the proposed planning problem, in order to improve the reliability of the system the Expected Energy Not Supplied (EENS) index of the system is limited by a constraint. For this purpose, Monte Carlo simulation method is used to determine the EENS. Particle Swarm Optimization (PSO) method is used to solve the proposed planning problem which is a nonlinear mixed integer optimization problem. Simulation results on Garver and RTS systems verify the effectiveness of the proposed planning problem for reduction of the total investment cost, EENS index and also increasing social welfare of the system.

Experimental evaluation of reactivity constraints for the closed-loop control of reactor power

International Nuclear Information System (INIS)

Bernard, J.A.; Lanning, D.D.; Ray, A.

1984-01-01

General principles for the closed-loop, digital control of reactor power have been identified, quantitatively enumerated, and experimentally demonstrated on the 5 MWt Research Reactor, MITR-II. The basic concept is to restrict the net reactivity so that it is always possible to make the reactor period infinite at the desired termination point of a transient by reversing the direction of motion of whatever control mechanism is associated with the controller. This capability is formally referred to as ''feasibility of control''. A series of ten experiments have been conducted over a period of eighteen months to demonstrate the efficacy of this property for the automatic control of reactor power. It has been shown that a controller which possesses this property is capable of both raising and lowering power in a safe, efficient manner while using a control rod of varying differential worth, that the reactivity constraints are a sufficient condition for the automatic control of reactor power, and that the use of a controller based on reactivity constraints can prevent overshoots either due to attempts to control a transient with a control rod of insufficient differential worth or due to failure to properly estimate when to commence rod insertion. Details of several of the more significant tests are presented together with a discussion of the rationale for the development of closed-loop control in large commercial power systems. Specific consideration is given to the motivation for designing a controller based on feasibility of control and the associated licensing issues

Reactive power control of wind farm using facts devices

International Nuclear Information System (INIS)

Ashfaq, S.; Arif, A.; Shakeel, A.; Mahmood, T.

2014-01-01

Wind energy is an attainable option to complement other types of pollution-free green generation Grid connections of renewable energy resources are vital if they are to be effectively exploited, but grid connection brings problems of voltage fluctuation and harmonic distortion. FACTs devices are one of the power electronics revolutions to improve voltage profile, system stability, and reactive power control and to reduce transmission losses. The studied system here is a variable speed wind generation system based on Induction Generator (IG) with integration of different FACTs controllers in the wind farm. To harness the wind power efficiently the most reliable and expensive system in the present era is grid connected doubly fed induction generator. Induction generator with FACTs devices is a suitable economical replacement. The suggested scheme is implemented in MATLAB Simulink with real time parameters of GHARO wind power plant in Sind, and corresponding results and output waveforms proves the potential strength of proposed methodology. (author)

Power saving regulated light emitting diode circuit

International Nuclear Information System (INIS)

Haville, G. D.

1985-01-01

A power saving regulated light source circuit, comprising a light emitting diode (LED), a direct current source and a switching transistor connected in series with the LED, a control voltage producing resistor connected in series with the LED to produce a control voltage corresponding to the current through the LED, a storage capacitor connected in parallel with the series combination of the LED and the resistor, a comparator having its output connected to the input of the transistor, the comparator having a reference input and a control input, a stabilized biasing source for supplying a stabilized reference voltage to the reference input, the control input of the comparator being connected to the control voltage producing resistor, the comparator having a high output state when the reference voltage exceeds the control voltage while having a low output state when the control voltage exceeds the reference voltage, the transistor being conductive in response to the high state while being nonconductive in response to the low state, the transistor when conductive being effective to charge the capacitor and to increase the control voltage, whereby the comparator is cycled between the high and low output states while the transistor is cycled between conductive and nonconductive states

Nuclear fuel saving assessment of poison-free control in LWRs [light water reactors

International Nuclear Information System (INIS)

Abu-Zaied, G.

1988-01-01

If neutron losses to control absorbers are to be eliminated, an alternative reactivity control system has to be introduced. Due to improved neutron economy, the fuel utilization of these other alternatives is better than for a conventional poison-controlled PWR [pressurized water reactor]. It is the objective in this work to assess the uranium savings attributable to reactivity control without poison. An investigation into the savings due to the elimination of PWR control by neutron capture has been carried out. The most important finding was that up to a 30% savings in natural uranium can be achieved if fuel to moderator ratio, V f /V m , of SSC [spectral-shift-control] core at EOC [end of cycle] is similar to the standard core V f /V m

Process stabilization by peak current regulation in reactive high-power impulse magnetron sputtering of hafnium nitride

International Nuclear Information System (INIS)

Shimizu, T; Villamayor, M; Helmersson, U; Lundin, D

2016-01-01

A simple and cost effective approach to stabilize the sputtering process in the transition zone during reactive high-power impulse magnetron sputtering (HiPIMS) is proposed. The method is based on real-time monitoring and control of the discharge current waveforms. To stabilize the process conditions at a given set point, a feedback control system was implemented that automatically regulates the pulse frequency, and thereby the average sputtering power, to maintain a constant maximum discharge current. In the present study, the variation of the pulse current waveforms over a wide range of reactive gas flows and pulse frequencies during a reactive HiPIMS process of Hf-N in an Ar–N 2 atmosphere illustrates that the discharge current waveform is a an excellent indicator of the process conditions. Activating the reactive HiPIMS peak current regulation, stable process conditions were maintained when varying the N 2 flow from 2.1 to 3.5 sccm by an automatic adjustment of the pulse frequency from 600 Hz to 1150 Hz and consequently an increase of the average power from 110 to 270 W. Hf–N films deposited using peak current regulation exhibited a stable stoichiometry, a nearly constant power-normalized deposition rate, and a polycrystalline cubic phase Hf-N with (1 1 1)-preferred orientation over the entire reactive gas flow range investigated. The physical reasons for the change in the current pulse waveform for different process conditions are discussed in some detail. (paper)

Single-point reactive power control method on voltage rise mitigation in residential networks with high PV penetration

DEFF Research Database (Denmark)

Hasheminamin, Maryam; Agelidis, Vassilios; Ahmadi, Abdollah

2018-01-01

Voltage rise (VR) due to reverse power flow is an important obstacle for high integration of Photovoltaic (PV) into residential networks. This paper introduces and elaborates a novel methodology of an index-based single-point-reactive power-control (SPRPC) methodology to mitigate voltage rise by ...... system with high r/x ratio. Efficacy, effectiveness and cost study of SPRPC is compared to droop control to evaluate its advantages.......Voltage rise (VR) due to reverse power flow is an important obstacle for high integration of Photovoltaic (PV) into residential networks. This paper introduces and elaborates a novel methodology of an index-based single-point-reactive power-control (SPRPC) methodology to mitigate voltage rise...... by absorbing adequate reactive power from one selected point. The proposed index utilizes short circuit analysis to select the best point to apply this Volt/Var control method. SPRPC is supported technically and financially by distribution network operator that makes it cost effective, simple and efficient...

Reduction of DC-link Capacitor in Case of Cascade Multilevel Converters by means of Reactive Power Control

DEFF Research Database (Denmark)

Gohil, Ghanshyamsinh Vijaysinh; Wang, Huai; Liserre, Marco

2014-01-01

A method to selectively control the amount of dc link voltage ripple by processing desired reactive power by a DC/DC converter in isolated AC/DC or AC/DC/AC system is proposed. The concept can reduce the dc link capacitors used for balancing the input and output power and thereby limiting...... the voltage ripple. It allows the use of smaller dc link capacitor and hence a longer lifetime and at the same time high power density and low cost can be achieved. The isolated DC/DC converter is controlled to process the desired reactive power in addition to the active power. The control system to achieve...

Combined Active and Reactive Power Control of Wind Farms based on Model Predictive Control

DEFF Research Database (Denmark)

Zhao, Haoran; Wu, Qiuwei; Wang, Jianhui

2017-01-01

This paper proposes a combined wind farm controller based on Model Predictive Control (MPC). Compared with the conventional decoupled active and reactive power control, the proposed control scheme considers the significant impact of active power on voltage variations due to the low X=R ratio...... of wind farm collector systems. The voltage control is improved. Besides, by coordination of active and reactive power, the Var capacity is optimized to prevent potential failures due to Var shortage, especially when the wind farm operates close to its full load. An analytical method is used to calculate...... the sensitivity coefficients to improve the computation efficiency and overcome the convergence problem. Two control modes are designed for both normal and emergency conditions. A wind farm with 20 wind turbines was used to verify the proposed combined control scheme....

High efficiency H6 single-phase transformerless grid-tied PV inverter with proposed modulation for reactive power generation

Science.gov (United States)

Almasoudi, Fahad M.; Alatawi, Khaled S.; Matin, Mohammad

2017-08-01

Implementation of transformerless inverters in PV grid-tied system offer great benefits such as high efficiency, light weight, low cost, etc. Most of the proposed transformerless inverters in literature are verified for only real power application. Currently, international standards such as VDE-AR-N 4105 has demanded that PV grid-tied inverters should have the ability of controlling a specific amount of reactive power. Generation of reactive power cannot be accomplished in single phase transformerless inverter topologies because the existing modulation techniques are not adopted for a freewheeling path in the negative power region. This paper enhances a previous high efficiency proposed H6 trnasformerless inverter with SiC MOSFETs and demonstrates new operating modes for the generation of reactive power. A proposed pulse width modulation (PWM) technique is applied to achieve bidirectional current flow through freewheeling state. A comparison of the proposed H6 transformerless inverter using SiC MOSFETs and Si MOSFTEs is presented in terms of power losses and efficiency. The results show that reactive power control is attained without adding any additional active devices or modification to the inverter structure. Also, the proposed modulation maintains a constant common mode voltage (CM) during every operating mode and has low leakage current. The performance of the proposed system verifies its effectiveness in the next generation PV system.

Variable flow controls of closed system pumps for energy savings in maritime power systems

OpenAIRE

Su, Chun-Lien; Liao, Chi-Hsiang; Chou, Tso-Chu; Chou, Ming-Hung; Guerrero, Josep M.

2016-01-01

Pumps are extensively used in maritime industries as marine vessels utilize a wide range of pumps and pumping techniques to transfer and distribute all types of air and fluids. The electrical energy consumed by the various motors accounts for about 70% of a vessel’s total power consumption, and this presents a problem in unique marine environments. Such situations are especially conducive to energy-saving strategies using variable frequency drives (VFDs) in centrifugal load service. This pape...

Core concept of fast power reactor with zero sodium void reactivity

International Nuclear Information System (INIS)

Matveev, V.I.; Chebeskov, A.N.; Krivitsky, I.Y.

1991-01-01

The paper presents a core concept of BN-800 - type fast power reactor with zero sodium void reactivity (SVR). Consideration is given to the layout-and some design features of such a core. Some considerations on the determination of the required SVR value as one of the fast reactor safety criteria in accidents with coolant boiling are presented. Some methodical considerations an the development of calculation models that give a correct description of the new core features are stated. The results of the integral SVR calculation studies are included. reactivity excursions under different scenarios of sodium boiling are estimated, some corrections into the calculated SVR value are discussed. (author)

Modified Monkey Optimization Algorithm for Solving Optimal Reactive Power Dispatch Problem

Directory of Open Access Journals (Sweden)

Kanagasabai Lenin

2015-04-01

Full Text Available In this paper, a novel approach Modified Monkey optimization (MMO algorithm for solving optimal reactive power dispatch problem has been presented. MMO is a population based stochastic meta-heuristic algorithm and it is inspired by intelligent foraging behaviour of monkeys. This paper improves both local leader and global leader phases.  The proposed (MMO algorithm has been tested in standard IEEE 30 bus test system and simulation results show the worthy performance of the proposed algorithm in reducing the real power loss.

CROSS LAYER COORDINATED ENERGY SAVING STRATEGY IN MANET

Institute of Scientific and Technical Information of China (English)

Xu Li; Zheng Baoyu

2003-01-01

Mobile Ad hoc NETwork (MANET) consists of a set of mobile hosts which can operate independently without infrastructure base stations. Energy saving is a critical issue for MANET since most mobile hosts will operate on battery powers. A cross layer coordinated framework for energy saving is proposed in this letter. On-demand power management, physical layer and medium access control layer dialogue based multi-packet reception, mobile agent based topology discovery and topology control based transmit power-aware and battery power-aware dynamic source routing are some of new ideas in this framework.

Economic analysis of reactive power compensation in a wind farm: Influence of Spanish energy policy

Energy Technology Data Exchange (ETDEWEB)

Martinez, E.; Daroca, F. [Grupo Eolicas Riojanas, Carretera de Laguardia, 91-93, 26006 Logrono, La Rioja (Spain); Sanz, F.; Blanco, J. [Department of Mechanical Engineering, University of La Rioja, Logrono, La Rioja (Spain); Jimenez, E. [Department of Electrical Engineering, University of La Rioja, Logrono, La Rioja (Spain)

2008-08-15

Presently, renewable energies and especially wind energy are gaining a special relevance in the electrical market worldwide. This current rate of growth brings with it the need for the various wind farms to not limit themselves to producing energy but also provide stability to the network within its capabilities. So, the actual objective is to adapt the installations that produce wind energy in such a way that they give a maximum amount of support in any given moment to the electrical network. For this purpose, there are governing techno-economic parameters that influence the economic behavior of commercial wind farms. A complete cost-benefit analysis model is developed, focused on incorporating automatic capacitor banks into wind farms for the compensation of reactive power. This economic analysis is about doubly fed induction generator (DFIG) wind turbines. Although this kind of wind turbines have a certain capability in terms of modulating reactive power, this capacity is not enough to achieve the new requirements of reactive power regulation in Spain and it is necessary to invest in systems of external compensation. In this paper, we have studied the case of DFIG wind turbine and capacitor banks, although the used methodology can be applied to other technologies as well by simply amplifying the algorithms according to the specific characteristics of the option elected. Following this premise, a detailed analysis of the specific needs of a wind farm has been carried out, as well as a search for the optimum performance for the compensation of reactive power. (author)

Economic analysis of reactive power compensation in a wind farm: Influence of Spanish energy policy

International Nuclear Information System (INIS)

Martinez, E.; Daroca, F.; Sanz, F.; Blanco, J.; Jimenez, E.

2008-01-01

Presently, renewable energies and especially wind energy are gaining a special relevance in the electrical market worldwide. This current rate of growth brings with it the need for the various wind farms to not limit themselves to producing energy but also provide stability to the network within its capabilities. So, the actual objective is to adapt the installations that produce wind energy in such a way that they give a maximum amount of support in any given moment to the electrical network. For this purpose, there are governing techno-economic parameters that influence the economic behavior of commercial wind farms. A complete cost-benefit analysis model is developed, focused on incorporating automatic capacitor banks into wind farms for the compensation of reactive power. This economic analysis is about doubly fed induction generator (DFIG) wind turbines. Although this kind of wind turbines have a certain capability in terms of modulating reactive power, this capacity is not enough to achieve the new requirements of reactive power regulation in Spain and it is necessary to invest in systems of external compensation. In this paper, we have studied the case of DFIG wind turbine and capacitor banks, although the used methodology can be applied to other technologies as well by simply amplifying the algorithms according to the specific characteristics of the option elected. Following this premise, a detailed analysis of the specific needs of a wind farm has been carried out, as well as a search for the optimum performance for the compensation of reactive power. (author)

Investigation of the behavior of a three phase grid-connected photovoltaic system to control active and reactive power

Energy Technology Data Exchange (ETDEWEB)

Tsengenes, Georgios; Adamidis, Georgios [Department of Electrical Engineering and Computer Engineering, Democritus University of Thrace, University Campus Kimmeria, 67100 Xanthi (Greece)

2011-01-15

In this paper, a photovoltaic (PV) system, with maximum power point tracking (MPPT), connected to a three phase grid is presented. The connection of photovoltaic system on the grid takes place in one stage using voltage source inverter (VSI). For a better utilization of the photovoltaic system, the control strategy applied is based on p-q theory. According to this strategy during sunlight the system sends active power to the grid and at the same time compensates the reactive power of the load. In case there is no sunlight (during the night for instance), the inverter only compensates the reactive power of the load. In this paper the use of p-q theory to supply the grid with active power and compensate the reactive power of the load is investigated. The advantage of this control strategy is that the photovoltaic system is operated the whole day. Furthermore, the p-q theory uses simple algebraic calculations without demanding the use of PLL to synchronize the inverter with the grid. (author)

Energy consumption and energy-saving potential analysis of pollutant abatement systems in a 1000MW coal-fired power plant.

Science.gov (United States)

Yang, Hang; Zhang, Yongxin; Zheng, Chenghang; Wu, Xuecheng; Chen, Linghong; Gao, Xiang; Fu, Joshua S

2018-05-10

The pollutant abatement systems are widely applied in the coal-fired power sector and the energy consumption was considered an important part of the auxiliary power. An energy consumption analysis and assessment model of pollutant abatement systems in a power unit was developed based on the dynamic parameters and technology. The energy consumption of pollutant abatement systems in a 1000 MW coal-fired power unit which meet the ultra-low emission limits and the factors of operating parameters including unit load and inlet concentration of pollutants on the operating power were analyzed. The results show that the total power consumption of the pollutant abatement systems accounted for 1.27% of the gross power generation during the monitoring period. The WFGD system consumed 67% of the rate while the SCR and ESP systems consumed 8.9% and 24.1%. The power consumption rate of pollutant abatement systems decreased with the increase of unit load and increased with the increase of the inlet concentration of pollutants. The operation adjustment was also an effective method to increase the energy efficiency. For example, the operation adjustment of slurry circulation pumps could promote the energy-saving operation of WFGD system. Implication Statement The application of pollutant abatement technologies increases the internal energy consumption of the power plant, which will lead to an increase of power generation costs. The real-time energy consumption of the different pollutant abatement systems in a typical power unit is analyzed based on the dynamic operating data. Further, the influence of different operating parameters on the operating power of the system and the possible energy-saving potential are analyzed.

Energy Saving Scheme Based On Traffic Forwarding For Optical Fiber Access Networks

DEFF Research Database (Denmark)

Lopez, G. Arturo Rodes; Estaran Tolosa, Jose Manuel; Vegas Olmos, Juan José

2013-01-01

We report on an energy saving block that regroups and powers off OLTs during low traffic periods, resulting in energy savings up to 87,5% in the central office of optical access networks.......We report on an energy saving block that regroups and powers off OLTs during low traffic periods, resulting in energy savings up to 87,5% in the central office of optical access networks....

Heavy Traffic Feasible Hybrid Intracycle and Cyclic Sleep for Power Saving in 10G-EPON

Directory of Open Access Journals (Sweden)

Xintian Hu

2014-01-01

Full Text Available Energy consumption in optical access networks costs carriers substantial operational expense (OPEX every year and is one of contributing factors for the global warming. To reduce energy consumption in the 10-gigabit Ethernet passive optical network (10G-EPON, a hybrid intracycle and cyclic sleep mechanism is proposed in this paper. Under heavy traffic load, optical network units (ONUs can utilize short idle slots within each scheduling cycle to enter intracycle sleep without postponing data transmission. In this way, energy conservation is achieved even under heavy traffic load with quality of service (QoS guarantee. Under light traffic load, ONUs perform long cyclic sleep for several scheduling cycles. The adoption of cyclic sleep instead of intracycle sleep under light traffic load can reduce unnecessary frequent transitions between sleep and full active work caused by using intracycle sleep. Further, the Markov chain of the proposed mechanism is established. The performances of the proposed mechanism and existing approaches are analyzed quantitatively based on the chain. For the proposed mechanism, power saving ability with QoS guarantee even under heavy traffic and better power saving performance than existing approaches are verified by the quantitative analysis. Moreover, simulations validate the above conclusions based on the chain.

A hybrid method of incorporating extended priority list into equal incremental principle for energy-saving generation dispatch of thermal power systems

International Nuclear Information System (INIS)

Cheng, Chuntian; Li, Shushan; Li, Gang

2014-01-01

The energy-saving generation dispatch (ESGD) policy released by Chinese Government in 2007 is a new code for optimally dispatching electric power generation portfolio in the country with the dual objectives of improving energy efficiency and reducing environmental pollution. The ESGD is substantially different from the competitive market in the developed economies, the traditional economic dispatching or the rational dispatching principle implemented in China prior to the new policy. This paper develops a hybrid method that integrates the extended priority list (EPL), the equal incremental principle (EIP) and a heuristic method to optimize daily generation schedules under ESGD. The EPL is presented to search desirable units set that satisfies the complicated duration period requirements based on thermal unit generation priority list. The EIP is developed to allocate load among the committed units within the combined set. A heuristic method is proposed to deal with inequality constraints, which usually result in difficulty for power allocation, and used to improve these results. The algorithm has been embedded into a newly developed decision support system that is currently being used by operators of the Guizhou Province Power Grid to make day-ahead quarter-hourly generation schedules. - Highlights: • Electric power industry is one of key and important fields for energy conservation and emission reduction in China. • The energy-saving generation dispatch policy was released by Chinese government in 2007. • A Hybrid algorithm for energy-saving generation dispatch scheduling of thermal power system is presented. • The algorithm has been embedded into a newly developed decision support system

EBRPOCO - a program to calculate detailed contributions of power reactivity components of EBR-II

International Nuclear Information System (INIS)

Meneghetti, D.; Kucera, D.A.

1981-01-01

The EBRPOCO program has been developed to facilitate the calculations of the power coefficients of reactivity of EBR-II loadings. The program enables contributions of various components of the power coefficient to be delineated axially for every subassembly. The program computes the reactivity contributions of the power coefficients resulting from: density reduction of sodium coolant due to temperature; displacement of sodium coolant by thermal expansions of cladding, structural rods, subassembly cans, and lower and upper axial reflectors; density reductions of these steel components due to temperature; displacement of bond-sodium (if present) in gaps by differential thermal expansions of fuel and cladding; density reduction of bond-sodium (if present) in gaps due to temperature; free axial expansion of fuel if unrestricted by cladding or restricted axial expansion of fuel determined by axial expansion of cladding. Isotopic spatial contributions to the Doppler component my also be obtained. (orig.) [de

76 FR 20459 - Savings and Loan Holding Company Application

Science.gov (United States)

2011-04-12

... DEPARTMENT OF THE TREASURY Office of Thrift Supervision Savings and Loan Holding Company... concerning the following information collection. Title of Proposal: Savings and Loan Holding Company... officer of a savings and loan holding company, or any individual who owns, controls, or holds with power...

Cogeneration an opportunity for industrial energy saving

International Nuclear Information System (INIS)

Pasha, R.A.; Butt, Z.S.

2011-01-01

This paper is about the cogeneration from industrial energy savings opportunities perspective. The energy crisis in these days forces industry to find ways to cope with critical situation. There are several energy savings options which if properly planned and implemented would be beneficial both for industry and community. One way of energy saving is Cogeneration i.e. Combined Heat and Power. The paper will review the basic methods, types and then discuss the suitability of these options for specific industry. It has been identified that generally process industry can get benefits of energy savings. (author)

Efficient Reactive Power Compensation Algorithm for Distribution Network

Directory of Open Access Journals (Sweden)

J. Jerome

2017-12-01

Full Text Available The use of automation and energy efficient equipment with electronic control would greatly improve industrial production.  These new devices are more sensitive to supply voltage deviation and the characteristics of the power system that was previously ignored are now very important. Hence the benefits of distribution automation have been widely acknowledged in recent years. This paper proposes an efficient load flow solution technique extended to find optimum location for reactive power compensation and network reconfiguration for planning and day-to-day operation of distribution networks.  This is required as a part of the distribution automation system (DAS for taking various control and operation decisions.  The method exploits the radial nature of the network and uses forward and backward propagation technique to calculate branch currents and node voltages.  The proposed method has been tested to analyze several practical distribution networks of various voltage levels and also having high R/X ratio.

Comprehensive Cost Minimization in Distribution Networks Using Segmented-time Feeder Reconfiguration and Reactive Power Control of Distributed Generators

DEFF Research Database (Denmark)

Chen, Shuheng; Hu, Weihao; Chen, Zhe

2016-01-01

In this paper, an efficient methodology is proposed to deal with segmented-time reconfiguration problem of distribution networks coupled with segmented-time reactive power control of distributed generators. The target is to find the optimal dispatching schedule of all controllable switches...... and distributed generators’ reactive powers in order to minimize comprehensive cost. Corresponding constraints, including voltage profile, maximum allowable daily switching operation numbers (MADSON), reactive power limits, and so on, are considered. The strategy of grouping branches is used to simplify...... (FAHPSO) is implemented in VC++ 6.0 program language. A modified version of the typical 70-node distribution network and several real distribution networks are used to test the performance of the proposed method. Numerical results show that the proposed methodology is an efficient method for comprehensive...

Save energy - for industry

International Nuclear Information System (INIS)

Anon.

1983-01-01

The article is an interview with Glenn Bjorklund, Vice President of SCalEd (Southern California Edison). The variations in Californian power demand and public electricity consumption habits are explained, together with types of power source used in electricity production. Questions are posed concerning SCalEd's energy saving strategy. The political implications of electricity charge changes are discussed. The planned energy resources for 1982-1992 are given with nuclear power being the largest contributor. (H.J.P./G.T.H.)

An Optimized Reactive Power Control of Distributed Solar Inverters in Low Voltage Networks

DEFF Research Database (Denmark)

Demirok, Erhan; Sera, Dezso; Teodorescu, Remus

2011-01-01

This study examines the reactive power ancillary services of solar inverters which are connected to low voltage (LV) distribution networks by giving attention to the grid voltage support service and grid losses. Two typical reference LV distribution network models as suburban and farm...... are introduced from the literature in order to evaluate contribution of two static droop strategies cosφ(P) and Q(U) on the grid voltage. Photovoltaic (PV) hosting capacities of the suburban and farm networks are estimated and the most predominant limitations of connecting more solar inverters are emphasized...... for each network type. Regarding the overloading of MV/LV distribution transformers, overloading of lines and the grid overvoltage limitations, new local grid voltage support methods (cosφ(P,U) and Q(U,P)) are also proposed. Resulting maximum allowable penetration levels with different reactive power...

Reactivity control of nuclear power reactors: new options

International Nuclear Information System (INIS)

Alcala, F.

1984-01-01

Some actual aspects (referring to economy, non-proliferation and environmental impact) of nuclear power reactors has been analyzed from the point of view of the reactivity control physics. Specially studied have been the physical mechanisms related with the spectral shift control method and their general positive effects on those aspects. The analysis carried out suggested the application of the above method of control to reactors with non-hydrogenous fuel cells, which are mainly characterized by their high moderator/fuel ratio. Finally three different types of such fuel cells are presented and some results about one of them (belonging to a PHWR controlled by graphite rods) are given. (author)

Energy Saving and Efficient Energy Use By Power Electronic Systems

DEFF Research Database (Denmark)

Blaabjerg, Frede; Wang, Huai; Davari, Pooya

2017-01-01

In the development of the modern society, one of the key factors is to save energy in order to become more independent of other energy resources. Two important approaches can be taken—one is to change behavior and thereby save energy—the second one is to develop new technology which is able to sa...

BN600 reactivity definition

International Nuclear Information System (INIS)

Zheltyshev, V.; Ivanov, A.

2000-01-01

Since 1980, the fast BN600 reactor with sodium coolant has been operated at Beloyarsk Nuclear Power Plant. The periodic monitoring of the reactivity modifications should be implemented in compliance with the standards and regulations applied in nuclear power engineering. The reactivity measurements are carried out in order to confirm the basic neutronic features of a BN600 reactor. The reactivity measurements are aimed to justify that nuclear safety is provided in course of the in-reactor installation of the experimental core components. Two reactivity meters are to be used on BN600 operation: 1. Digital on-line reactivity calculated under stationary reactor operation on power (approximation of the point-wise kinetics is applied). 2. Second reactivity meter used to define the reactor control rod operating components efficiency under reactor startup and take account of the changing efficiency of the sensor, however, this is more time-consumptive than the on-line reactivity meter. The application of two reactivity meters allows for the monitoring of the reactor reactivity under every operating mode. (authors)

Investigation of extra power loss sharing among photovoltaic inverters caused by reactive power management in distribution networks

DEFF Research Database (Denmark)

Demirok, Erhan; Sera, Dezso; Teodorescu, Remus

2014-01-01

load and power loss on the feeders and individual inverters. Simplified energy loss evaluation is carried out here by using analytical average loss modeling of 2-level full bridge inverter coupled with network load flow analysis simulating one month period. The study shows that whatever Q control......Grid-connected photovoltaic (PV) inverters tailored with reactive power management feature can support the grid voltage especially when the voltage fluctuates near its admissible limits. Although Q control allows reducing the grid voltage elevation along the distribution feeder, it brings extra...... is selected, extra power loss is not a substantial amount to take into consideration. Similarly, loss difference among the inverters located at the various points is negligible....

Obtaining additional energy savings from the Filumex project by means of the reactive power compensation; Obtencion de ahorros adicionales del proyecto Filumex mediante la compensacion de la potencia reactiva

Energy Technology Data Exchange (ETDEWEB)

Cervantes Jaramillo, Enrique L.; Loredo Gutierrez, Miguel Angel; Hernandez Hernandez, Eduardo [Comision Federal de Electricidad, Mexico, D. F. (Mexico)

1996-12-31

This paper presents the proposal for establishing in a parallel way to Flamex project, the compensation in the intermediate tension network for the increment in reactive power supplied to the domestic user. This is due to the following three phenomena that occur in replacing incandescent light bulbs with fluorescent lamps: a) A fluorescent lamp has a power factor of 0.9; consequently it requires the supply of a reactive power of about 50% of its capacity. b) In replacing an incandescent light bulb for a fluorescent lamp, approximately 80% of its capacity is not supplied, this leads to the disappearance of a good deal of the user`s purely resistive load, that will cause that its natural power factor is decreased from 0.91 to 0.86 lagging. c) In decreasing the annual maximum demand in the distribution circuit in a greater proportion than the decrease of the annual consumption, their load factors and the annual losses will be increased and therefore the share of its annual energy losses will be increased in about 18.9%. The above, gives rise to the fact that the compensation of reactive power by means of the installation of capacitor banks in the main leads of the distribution circuit, turns out to be a highly appealing technical-economical solution, with a Benefit/Cost rate of 4, a return time of the investment of 2 years and a net benefit of $4.78/user (Pesos). [Espanol] Se presenta la propuesta para establecer en una forma paralela al proyecto FILUMEX, la compensacion en la red de media tension del incremento de la potencia reactiva suministrada al usuario domestico. Este es debido a los siguientes tres fenomenos que ocurren al sustituir los focos incandescentes por lamparas fluorescentes: a) Una lampara fluorescente tiene un factor de potencia de 0.9, por lo que requiere el suministro de una potencia reactiva de aproximadamente el 50% de su capacidad. b) Al sustituirse un foco incandescente por una lampara fluorescente, se deja de suministrar aproximadamente el 80

Obtaining additional energy savings from the Filumex project by means of the reactive power compensation; Obtencion de ahorros adicionales del proyecto Filumex mediante la compensacion de la potencia reactiva

Energy Technology Data Exchange (ETDEWEB)

Cervantes Jaramillo, Enrique L; Loredo Gutierrez, Miguel Angel; Hernandez Hernandez, Eduardo [Comision Federal de Electricidad, Mexico, D. F. (Mexico)

1997-12-31

This paper presents the proposal for establishing in a parallel way to Flamex project, the compensation in the intermediate tension network for the increment in reactive power supplied to the domestic user. This is due to the following three phenomena that occur in replacing incandescent light bulbs with fluorescent lamps: a) A fluorescent lamp has a power factor of 0.9; consequently it requires the supply of a reactive power of about 50% of its capacity. b) In replacing an incandescent light bulb for a fluorescent lamp, approximately 80% of its capacity is not supplied, this leads to the disappearance of a good deal of the user`s purely resistive load, that will cause that its natural power factor is decreased from 0.91 to 0.86 lagging. c) In decreasing the annual maximum demand in the distribution circuit in a greater proportion than the decrease of the annual consumption, their load factors and the annual losses will be increased and therefore the share of its annual energy losses will be increased in about 18.9%. The above, gives rise to the fact that the compensation of reactive power by means of the installation of capacitor banks in the main leads of the distribution circuit, turns out to be a highly appealing technical-economical solution, with a Benefit/Cost rate of 4, a return time of the investment of 2 years and a net benefit of $4.78/user (Pesos). [Espanol] Se presenta la propuesta para establecer en una forma paralela al proyecto FILUMEX, la compensacion en la red de media tension del incremento de la potencia reactiva suministrada al usuario domestico. Este es debido a los siguientes tres fenomenos que ocurren al sustituir los focos incandescentes por lamparas fluorescentes: a) Una lampara fluorescente tiene un factor de potencia de 0.9, por lo que requiere el suministro de una potencia reactiva de aproximadamente el 50% de su capacidad. b) Al sustituirse un foco incandescente por una lampara fluorescente, se deja de suministrar aproximadamente el 80

Integrated power-saving motor for power-demands of less than one kilowatt; Integral-Sparmotor im Leistungsbereich < 1 kW

Energy Technology Data Exchange (ETDEWEB)

Lindegger, M.; Kreuzer, H.H.; Lischer, G.

2005-10-15

This annual report for the Swiss Federal Office of Energy (SFOE) takes a look at the results of the second phase of a project concerning the development of integrated energy-saving electrical motors in the power range less than one kilowatt. The search for industrial partners is commented on and the publishing of an initial functional prototype on the Internet is mentioned. Participation at various fairs and the publication of articles in the technical press are mentioned. Further work on the motor is described, as is development work done on the drive electronics and the associated software. Further work planned is described.

A Modular Cascaded Multilevel Inverter Based Shunt Hybrid Active Power Filter for Selective Harmonic and Reactive Power Compensation Under Distorted/Unbalanced Grid Voltage Conditions

Directory of Open Access Journals (Sweden)

T. Demirdelen

2016-10-01

Full Text Available In recent years, shunt hybrid active power filters are being increasingly considered as a viable alternative to both passive filters and active power filters for compensating harmonics. In literature, their applications are restricted to balanced systems and low voltage applications and therefore not for industrial applications. This paper investigates the performance of a modular cascaded multilevel inverter based Shunt Hybrid Active Power Filter (SHAPF for reactive power compensation and selective harmonics elimination under distorted/unbalanced grid voltage conditions in medium voltage levels. In the proposed control method, reactive power compensation is achieved successfully with a perceptible amount and the performance results of harmonic compensation are satisfactory. Theoretical analysis and simulation results are obtained from an actual industrial network model in PSCAD. The simulation results are presented for a proposed system in order to demonstrate that the harmonic compensation performance meets the IEEE-519 standard.

A Novel Power-Saving Transmission Scheme for Multiple-Component-Carrier Cellular Systems

Directory of Open Access Journals (Sweden)

Yao-Liang Chung

2016-04-01

Full Text Available As mobile data traffic levels have increased exponentially, resulting in rising energy costs in recent years, the demand for and development of green communication technologies has resulted in various energy-saving designs for cellular systems. At the same time, recent technological advances have allowed multiple component carriers (CCs to be simultaneously utilized in a base station (BS, a development that has made the energy consumption of BSs a matter of increasing concern. To help address this concern, herein we propose a novel scheme aimed at efficiently minimizing the power consumption of BS transceivers during transmission, while still ensuring good service quality and fairness for users. Specifically, the scheme utilizes the dynamic activation/deactivation of CCs during data transmission to increase power usage efficiency. To test its effectiveness, the proposed scheme was applied to a model consisting of a BS with orthogonal frequency division multiple access-based CCs in a downlink transmission environment. The results indicated that, given periods of relatively light traffic loads, the total power consumption of the proposed scheme is significantly lower than that of schemes in which all the CCs of a BS are constantly activated, suggesting the scheme’s potential for reducing both energy costs and carbon dioxide emissions.

A Hybrid Estimator for Active/Reactive Power Control of Single-Phase Distributed Generation Systems with Energy Storage

DEFF Research Database (Denmark)

Pahlevani, Majid; Eren, Suzan; Guerrero, Josep M.

2016-01-01

This paper presents a new active/reactive power closed-loop control system for a hybrid renewable energy generation system used for single-phase residential/commercial applications. The proposed active/reactive control method includes a hybrid estimator, which is able to quickly and accurately es...

Measurement based analysis of active and reactive power losses in a distribution network with wind farms and CHPs

DEFF Research Database (Denmark)

Lund, Torsten

2007-01-01

The paper presents an investigation of the active and reactive power losses in a distribution network with wind turbines and combined heat and power plants. The investigation is based on 15 min average power measurements and load flow calculations in the power system simulation tool PowerFactory...

Measurements of the Reactivity Properties of the Aagesta Nuclear Power Reactor at Zero Power

Energy Technology Data Exchange (ETDEWEB)

Bernander, G

1967-07-15

The moderator level and temperature coefficients of reactivity and control rod differential reactivity worths have been determined at zero power by means of period measurements. The moderator level coefficient and the corresponding critical level have been measured for the 32, 68 and 136 fuel assembly cores at room temperature for cores with and without control rods. From these results the worths of control rods have been derived. HETERO calculations give up to 15 % lower values than the experimental results. The cold fresh core has an excess reactivity of 9.0 {+-} 0.2 %. The temperature coefficient and differential control rod worths were measured for the fully loaded core with filled tank in the temperature range between 30 and 210 deg C. Critical positions as a function of temperature were obtained for the corresponding control rod groups. No relevant calculations of the temperature coefficient for comparison with the experimental values have yet been made, but the experimental results together with measured critical control rod positions give good opportunities to check calculational programs. HETERO has been shown in these cases to reproduce differential control rod worths and critical positions fairly well. However, a certain underestimation of the rod effectiveness is quite noticeable. The relative increase in control rod effectiveness with a temperature change from 20 to 220 deg C has been estimated to be 0.29 {+-} 0.06.

Replacement or additional purchase: The impact of energy-efficient appliances on household electricity saving under public pressures

International Nuclear Information System (INIS)

Mizobuchi, Kenichi; Takeuchi, Kenji

2016-01-01

This study examined the influence of additional and replacement purchases of energy-efficient air-conditioners on power savings. We used a questionnaire survey and measured electricity use data from 339 Japanese households, collected from two city areas with different level of government-requested electricity-saving rates, namely, Osaka (10%) and Matsuyama (5%). The main findings of our study are as follows: (1) Households that purchased energy-efficient air-conditioners saved more electricity than those that did not. (2) “Additional-purchase households” showed significant energy savings, whereas “replacement households” did not. The rebound effect may negate the energy-saving effects of a new air-conditioner. (3) Altruistic attitude is associated with more active participation in power saving. (4) Households in Osaka saved more electricity than those in Matsuyama, probably because the government call to save electricity was more forceful. - Highlights: •Energy efficient air conditioner purchases affect household power savings. •Additional air conditioner purchase led to significant energy savings. •Replacement units did not produce more savings than non-purchase. • “Electricity conservation directives” amount had a significant power-saving effect. •Altruistic households were more likely to cooperate with power-saving requests.

Reactivation of nuclear power plant construction projects. Plant status, policy issues and regulatory options

International Nuclear Information System (INIS)

Spangler, M.B.

1986-07-01

Prior to the TMI-2 accident on March 28, 1979, four nuclear power plant units that had previously been issued a construction permit were cancelled, principally because of reduced projections of regional power demand. Since that time, an additional 31 units with CPs have been cancelled and eight units deferred. On December 23, 1985 one of the deferred units (Limerick-2) was reactivated and construction resumed. The primary objective of this policy study is to identify the principal issues requiring office-level consideration in the event of reactivation of the construction of one or more of the nuclear power plants falling into two categories: (1) LWR units issued a construction permit whose construction has been cancelled, and (2) LWR units whose construction has been deferred. The study scope is limited to identifying regulatory issues or questions deserving analysis rather than providing, at this time, answers or recommended actions. Five tasks are addressed: a tabulation and discussion of the status of all cancelled and deferred LWR units; and identification of potential safety and environmental issues; an identification of regulatory or policy issues and needed information to determine the desirability of revising certain rules and policies; and identification of regulatory options and decision criteria; and an identification of decision considerations in determining staff requirements and organizational coordination of LWR reactivation policy and implementation efforts. 41 refs

Sensitivity analysis for reactivity and power density investigations in nuclear reactors

International Nuclear Information System (INIS)

Naguib, K.; Morcos, H.N.; Sallam, O.H.; Abdelsamei, SH.

1993-01-01

Sensitivity analysis theory based on the variational functional approaches was applied to evaluate sensitivities of eigenvalues and power densities due to variation of the absorber concentration in the reactor core. The practical usefulness of this method is illustrated by considering test cases. The result indicates that this method is as accurate as those obtained from direct calculations, yet it provides an economical means in saving computational time since it requires fewer calculations. The SARC-1/2 code have been written in Fortran-77 to solve this problem.3 tab. 1 fig

Reactive Power Control for Improving Wind Turbine System Behavior Under Grid Faults

DEFF Research Database (Denmark)

Rodriguez, P.; Timbus, A.; Teodorescu, Remus

2009-01-01

This letter aims to present a generalized vector-based formulation for calculating the grid-side current reference to control reactive power delivered to the grid. Strategies for current reference generation were implemented on the abc stationary reference frame, and their effectivenesswas...... demonstrated experimentally, perhaps validating the theoretical analysis even under grid fault conditions....

Reactive Power Support of Electrical Vehicle Charging Station Upgraded with Flywheel Energy Storage System

DEFF Research Database (Denmark)

SUN, BO; Dragicevic, Tomislav; Savaghebi, Mehdi

2015-01-01

Electrical vehicles (EVs) are presenting increasingly potential to replace the conventional fossil fuel based vehicles due to environmental friendly characteristic. Accordingly, Charging Stations (CS), as an intermediate between grid and large numbers of EVs, are supposed to have more critical...... influence on future smart transportation network. This paper explores an off-board charging station upgraded with flywheel energy storage system that could provide a reactive power support to the grid utility. A supervisory control scheme based on distributed bus signaling is proposed to coordinate...... the operation of each component in the system. As a result, the charging station could supply the reactive power support to the utility grid without compromising the charging algorithm and preserve the battery’s lifetime. Finally, the real-time simulation results based on dSPACE1006 verifies the proposed...

Heat savings in energy systems with substantial distributed generation

DEFF Research Database (Denmark)

Østergaard, PA

2003-01-01

In Denmark, the integration of wind power is affected by a large amount of cogeneration of heat and power. With ancillary services supplied by large-scale condensation and combined heat and power (CHP) plants, a certain degree of large-scale generation is required regardless of momentary wind input......, if a certain production is required regardless of whether over-all electricity generation is sufficient. This article analyses this and although heat savings do have a negative impact on the amount of wind power the system may integrate a given moment in certain cases, associated fuel savings are notable...

Optimal stochastic reactive power scheduling in a microgrid considering voltage droop scheme of DGs and uncertainty of wind farms

International Nuclear Information System (INIS)

Khorramdel, Benyamin; Raoofat, Mahdi

2012-01-01

Distributed Generators (DGs) in a microgrid may operate in three different reactive power control strategies, including PV, PQ and voltage droop schemes. This paper proposes a new stochastic programming approach for reactive power scheduling of a microgrid, considering the uncertainty of wind farms. The proposed algorithm firstly finds the expected optimal operating point of each DG in V-Q plane while the wind speed is a probabilistic variable. A multi-objective function with goals of loss minimization, reactive power reserve maximization and voltage security margin maximization is optimized using a four-stage multi-objective nonlinear programming. Then, using Monte Carlo simulation enhanced by scenario reduction technique, the proposed algorithm simulates actual condition and finds optimal operating strategy of DGs. Also, if any DGs are scheduled to operate in voltage droop scheme, the optimum droop is determined. Also, in the second part of the research, to enhance the optimality of the results, PSO algorithm is used for the multi-objective optimization problem. Numerical examples on IEEE 34-bus test system including two wind turbines are studied. The results show the benefits of voltage droop scheme for mitigating the impacts of the uncertainty of wind. Also, the results show preference of PSO method in the proposed approach. -- Highlights: ► Reactive power scheduling in a microgrid considering loss and voltage security. ► Stochastic nature of wind farms affects reactive power scheduling and is considered. ► Advantages of using the voltage droop characteristics of DGs in voltage security are shown. ► Power loss, voltage security and VAR reserve are three goals of a multi-objective optimization. ► Monte Carlo method with scenario reduction is used to determine optimal control strategy of DGs.

Fuel Savings Potential from Future In-motion Wireless Power Transfer (WPT); NREL (National Renewable Energy Laboratory)

Energy Technology Data Exchange (ETDEWEB)

Burton, E.; Wang, L.; Gonder, J.; Brooker, A.; Konan, A.

2015-02-10

This presentation discusses the fuel savings potential from future in-motion wireless power transfer. There is an extensive overlap in road usage apparent across regional vehicle population, which occurs primarily on high-capacity roads--1% of roads are used for 25% of the vehicle miles traveled. Interstates and highways make up between 2.5% and 4% of the total roads within the Consolidated Statistical Areas (CSAs), which represent groupings of metropolitan and/or micropolitan statistical areas. Mileage traveled on the interstates and highways ranges from 54% in California to 24% in Chicago. Road electrification could remove range restrictions of electric vehicles and increase the fuel savings of PHEVs or HEVs if implemented on a large scale. If 1% of the road miles within a geographic area are electrified, 25% of the fuel used by a 'fleet' of vehicles enabled with the technology could be displaced.

A Hierarchical Modeling for Reactive Power Optimization With Joint Transmission and Distribution Networks by Curve Fitting

DEFF Research Database (Denmark)

Ding, Tao; Li, Cheng; Huang, Can

2018-01-01

–slave structure and improves traditional centralized modeling methods by alleviating the big data problem in a control center. Specifically, the transmission-distribution-network coordination issue of the hierarchical modeling method is investigated. First, a curve-fitting approach is developed to provide a cost......In order to solve the reactive power optimization with joint transmission and distribution networks, a hierarchical modeling method is proposed in this paper. It allows the reactive power optimization of transmission and distribution networks to be performed separately, leading to a master...... optimality. Numerical results on two test systems verify the effectiveness of the proposed hierarchical modeling and curve-fitting methods....

Taxation and the household saving rate: evidence from OECD countries

Directory of Open Access Journals (Sweden)

Vito Tanzi

2000-03-01

Full Text Available This paper analyzes anew the relationship between taxation and the household saving rate. On the basis of standard savings and tax revenue data from a sample of OECD countries, it provides compelling empirical evidence of a powerful impact of taxes on household savings. In particular, income taxes are shown to affect negatively the household saving rate much more than consumption taxes.

Energy Saving in Data Processing and Communication Systems

Directory of Open Access Journals (Sweden)

Giuseppe Iazeolla

2014-01-01

Full Text Available The power management of ICT systems, that is, data processing (Dp and telecommunication (Tlc systems, is becoming a relevant problem in economical terms. Dp systems totalize millions of servers and associated subsystems (processors, monitors, storage devices, etc. all over the world that need to be electrically powered. Dp systems are also used in the government of Tlc systems, which, besides requiring Dp electrical power, also require Tlc-specific power, both for mobile networks (with their cell-phone towers and associated subsystems: base stations, subscriber stations, switching nodes, etc. and for wired networks (with their routers, gateways, switches, etc.. ICT research is thus expected to investigate into methods to reduce Dp- and Tlc-specific power consumption. However, saving power may turn into waste of performance, in other words, into waste of ICT quality of service (QoS. This paper investigates the Dp and Tlc power management policies that look at compromises between power saving and QoS.

Mission aware energy saving strategies for Army ground vehicles

Science.gov (United States)

Dattathreya, Macam S.

Fuel energy is a basic necessity for this planet and the modern technology to perform many activities on earth. On the other hand, quadrupled automotive vehicle usage by the commercial industry and military has increased fuel consumption. Military readiness of Army ground vehicles is very important for a country to protect its people and resources. Fuel energy is a major requirement for Army ground vehicles. According to a report, a department of defense has spent nearly $13.6 billion on fuel and electricity to conduct ground missions. On the contrary, energy availability on this plant is slowly decreasing. Therefore, saving energy in Army ground vehicles is very important. Army ground vehicles are embedded with numerous electronic systems to conduct missions such as silent and normal stationary surveillance missions. Increasing electrical energy consumption of these systems is influencing higher fuel consumption of the vehicle. To save energy, the vehicles can use any of the existing techniques, but they require complex, expensive, and time consuming implementations. Therefore, cheaper and simpler approaches are required. In addition, the solutions have to save energy according to mission needs and also overcome size and weight constraints of the vehicle. Existing research in the current literature do not have any mission aware approaches to save energy. This dissertation research proposes mission aware online energy saving strategies for stationary Army ground vehicles to save energy as well as to meet the electrical needs of the vehicle during surveillance missions. The research also proposes theoretical models of surveillance missions, fuzzy logic models of engine and alternator efficiency data, and fuzzy logic algorithms. Based on these models, two energy saving strategies are proposed for silent and normal surveillance type of missions. During silent mission, the engine is on and batteries power the systems. During normal surveillance mission, the engine is

An extra power saving scheme for prolonging lifetime of mobile handset in the 4G mobile networks.

Science.gov (United States)

Chen, Jenhui; Tarn, Woei-Hwa; Lee, Jiann-Der

2014-01-01

In the fourth generation or next generation networks, services of non-real-time variable bit rate (NRT-VBR) and best effort (BE) will dominate over 85% of the total traffic in the networks. In this paper, we study the power saving mechanism of NRT-VBR and BE services for mobile handsets (MHs) to prolong their battery lifetime (i.e., the sustained operation duration) in the fourth generation networks. Because the priority of NRT-VBR and BE is lower than that of real-time VBR (RT-VBR) or guaranteed bit rate (GBR) services, we investigate an extended sleep mode for lower priority services (e.g., NRT-VBR and BE) in an MH to conserve the energy. The extended sleep mode is used when the MH wakes up from the sleep mode but it cannot obtain the bandwidth from base station (BS). The proposed mechanism, named extra power saving scheme (EPSS), uses the M/M/k/k Markovian queuing model to estimate the extended sleep duration to let MHs conserve their battery energy when the networks traffic is congested. To study the performance of EPSS, an accurate analysis model of energy is presented and validated by taking a series of simulations. Numerical experiments show that EPSS can achieve 43% extra energy conservation at most when downlink resource is saturated. We conclude that the energy of MHs can be conserved further by applying EPSS when the traffic load is saturated. The effect of energy saving becomes more obvious when the portion of NRT-VBR and BE services is greater than that of RT-VBR and GBR services.

Dependence of RF power on the content and configuration of hydrogen in amorphous hydrogenated silicon by reactive sputtering

Energy Technology Data Exchange (ETDEWEB)

Imura, T; Ushita, K; Mogi, K; Hiraki, A [Osaka Univ., Suita (Japan). Faculty of Engineering

1981-06-01

Infrared absorption spectra at stretching bands of Si-H were investigated in hydrogenated amorphous silicon fabricated by reactive sputtering in the atmosphere of Ar and H/sub 2/ (10 mole%) at various input rf powers in the range from 0.8 to 3.8 W/cm/sup 2/. Hydrogen content mainly due to the configuration of Si=H/sub 2/ in the film increased with the decreasing rf power, as the deposition rate was decreased. On the other hand, the quantity of the monohydride (Si-H) configuration depended less on the power. Attachment of hydrogen molecules onto the fresh and reactive surface of silicon deposited successively was proposed for possible process of hydrogen incusion into amorphous silicon resulting in Si=H/sub 2/ configuration. The photoconductivity increased as the input power became higher, when the deposition rate also increased linearly with the power.

SLAC synchronous condenser

International Nuclear Information System (INIS)

Corvin, C.

1995-06-01

A synchronous condenser is a synchronous machine that generates reactive power that leads real power by 90 degrees in phase. The leading reactive power generated by the condenser offsets or cancels the normal lagging reactive power consumed by inductive and nonlinear loads at the accelerator complex. The quality of SLAC's utility power is improved with the addition of the condenser. The inertia of the condenser's 35,000 pound rotor damps and smoothes voltage excursions on two 12 kilovolt master substation buses, improving voltage regulation site wide. The condenser absorbs high frequency transients and noise in effect ''scrubbing'' the electric system power at its primary distribution source. In addition, the condenser produces a substantial savings in power costs. Federal and investor owned utilities that supply electric power to SLAC levy a monthly penalty for lagging reactive power delivered to the site. For the 1993 fiscal year this totaled over $285,000 in added costs for the year. By generating leading reactive power on site, thereby reducing total lagging reactive power requirements, a substantial savings in electric utility bills is achieved. Actual savings of $150,000 or more a year are possible depending on experimental operations

A Hierarchical Control Scheme for Reactive Power and Harmonic Current Sharing in Islanded Microgrids

DEFF Research Database (Denmark)

Lorzadeh, Iman; Firoozabadi, Mehdi Savaghebi; Askarian Abyaneh, Hossein

2015-01-01

In this paper, a hierarchical control scheme consisting of primary and secondary levels is proposed for achieving accurate reactive power and harmonic currents sharing among interface inverters of distributed generators (DGs) in islanded microgrids. Firstly, fundamental and main harmonic componen...

Automatic determination of pressurized water reactor core loading patterns that maximize beginning-of-cycle reactivity within power-peaking and burnup constraints

International Nuclear Information System (INIS)

Hobson, G.H.; Turinsky, P.J.

1986-01-01

Computational capability has been developed to automatically determine a good estimate of the core loading pattern, which minimizes fuel cycle costs for a pressurized water reactor (PWR). Equating fuel cycle cost minimization with core reactivity maximization, the objective is to determine the loading pattern that maximizes core reactivity while satisfying power peaking, discharge burnup, and other constraints. The method utilizes a two-dimensional, coarse-mesh, finite difference scheme to evaluate core reactivity and fluxes for an initial reference loading pattern. First-order perturbation theory is applied to determine the effects of assembly shuffling on reactivity, power distribution, end-of-cycle burnup. Monte Carlo integer programming is then used to determine a near-optimal loading pattern within a range of loading patterns near the reference pattern. The process then repeats with the new loading pattern as the reference loading pattern and terminates when no better loading pattern can be determined. The process was applied with both reactivity maximization and radial power-peaking minimization as objectives. Results on a typical large PWR indicate that the cost of obtaining an 8% improvement in radial power-peaking margin is ≅2% in fuel cycle costs, for the reload core loaded without burnable poisons that was studied

Energy Saving by Chopping off Peak Demand Using Day Light

Directory of Open Access Journals (Sweden)

Ashok Kumar Maitra

2011-08-01

Full Text Available An artificial intelligent technique has been implemented in this research using real time datas to calculate how much energy can be chopped from peak load demand. The results are based on real time data that are taken from power delivering centers. These datas do reflect the present condition of power and a solution to those critical conditions during the peak period. These are done in such a way such that helps in judicious scheduling of load. The time based load scheduling has been done so as to understand the basic criteria for solving power crisis during morning peak and early evening peak. The sunray availability and percentage of load that will use day light saving (DLS technique has been taken into account in this work. The results shows that about 0.5% to 1% of load can be shedded off from the peak load period which otherwise is reduction of power. Thus it otherwise also means that an equivalent amount of energy is saved which amounts to a large saving of national money. This result is obtained on monthly and even daily basis. Thus this paper justifies DLS gives a new renewable technique to save energy.

[Effects of Reactive Jump Training in Handball Players Regarding Jump Height and Power Development in the Triceps Surae Muscle].

Science.gov (United States)

Rensing, N; Westermann, A; Möller, D; von Piekartz, H

2015-12-01

Studies have shown changes in the technical and physical demands in modern handball. The game has increased considerably in speed, power and dynamics. Jump training has, therefore, become ever more important in the training of the athletes. These developments contribute to the fact that handball is now one of the most injury-prone types of sport, with the lower extremities being most frequently affected. Reactive jump training is not only used in training by now, but also increasingly in injury prevention. The aim of this study was to investigate the effectiveness of reactive jump training with handball players. 21 regional league handball players were randomly divided into an intervention group (n = 12) and a control group (n = 9). The intervention group completed a six-week reactive jump training programme while the control group went through a non-specific training programme. Jump height (squat and counter movement jump), isokinetic and isometric maximum power as well as muscle activity served as measuring parameters. A comparison of the intervention and control groups revealed that the reactive jump training led to significant improvements in jump height. The isometric and isokinetic maximum power measurements and the electromyographic activities of the triceps surae muscle demonstrated an improvement in the values within the intervention group. However, this improvement was not significant compared with the control group. Likewise both jumps correlated with the muscle activity of the soleus muscle as shown by electromyography. A moderate correlation was noticed between the isokinetic maximum power measurement and the electromyographic activity of the soleus and gastrocnemius medialis muscles. Furthermore, the correlations of the isometric and isokinetic maximum power meas-urements resulted in a strong correlation coefficient. This study revealed a significant increase in jump height after reactive jump training. There was no significant difference in

A novel evolutionary algorithm for dynamic economic dispatch with energy saving and emission reduction in power system integrated wind power

International Nuclear Information System (INIS)

Liao, Gwo-Ching

2011-01-01

An optimization algorithm is proposed in this paper to solve the economic dispatch problem that includes wind farm using the Chaotic Quantum Genetic Algorithm (CQGA). In addition to the detailed models of economic dispatch introduction and their associated constraints, the wind power effect is also included in this paper. The chaotic quantum genetic algorithm used to solve the economic dispatch process and discussed with real scenarios used for the simulation tests. After comparing the proposed algorithm with several other algorithms commonly used to solve optimization problems, the results show that the proposed algorithm is able to find the optimal solution quickly and accurately (i.e. to obtain the minimum cost for power generation in the shortest time). At the end, the impact to the total cost savings for power generation after adding (or not adding) wind power generation is also discussed. The actual implementation results prove that the proposed algorithm is economical, fast and practical. They are quite valuable for further research. -- Research highlights: → Quantum Genetic Algorithm can effectively improve the global search ability. → It can achieve the real objective of the global optimal solutions. → The CPU computation time is less than that other algorithms adopted in this paper.

A new algorithm for optimum voltage and reactive power control for minimizing transmission lines losses

International Nuclear Information System (INIS)

Ghoudjehbaklou, H.; Danai, B.

2001-01-01

Reactive power dispatch for voltage profile modification has been of interest to power utilities. Usually local bus voltages can be altered by changing generator voltages, reactive shunts, ULTC transformers and SVCs. Determination of optimum values for control parameters, however, is not simple for modern power system networks. Heuristic and rather intelligent algorithms have to be sought. In this paper a new algorithm is proposed that is based on a variant of a genetic algorithm combined with simulated annealing updates. In this algorithm a fuzzy multi-objective a approach is used for the fitness function of the genetic algorithm. This fuzzy multi-objective function can efficiently modify the voltage profile in order to minimize transmission lines losses, thus reducing the operating costs. The reason for such a combination is to utilize the best characteristics of each method and overcome their deficiencies. The proposed algorithm is much faster than the classical genetic algorithm and cna be easily integrated into existing power utilities software. The proposed algorithm is tested on an actual system model of 1284 buses, 799 lines, 1175 fixed and ULTC transformers, 86 generators, 181 controllable shunts and 425 loads

Recursive Pyramid Algorithm-Based Discrete Wavelet Transform for Reactive Power Measurement in Smart Meters

Directory of Open Access Journals (Sweden)

Mahin K. Atiq

2013-09-01

Full Text Available Measurement of the active, reactive, and apparent power is one of the most fundamental tasks of smart meters in energy systems. Recently, a number of studies have employed the discrete wavelet transform (DWT for power measurement in smart meters. The most common way to implement DWT is the pyramid algorithm; however, this is not feasible for practical DWT computation because it requires either a log N cascaded filter or O (N word size memory storage for an input signal of the N-point. Both solutions are too expensive for practical applications of smart meters. It is proposed that the recursive pyramid algorithm is more suitable for smart meter implementation because it requires only word size storage of L × Log (N-L, where L is the length of filter. We also investigated the effect of varying different system parameters, such as the sampling rate, dc offset, phase offset, linearity error in current and voltage sensors, analog to digital converter resolution, and number of harmonics in a non-sinusoidal system, on the reactive energy measurement using DWT. The error analysis is depicted in the form of the absolute difference between the measured and the true value of the reactive energy.

Energy-saving operation of a converter-fed synchronous machine

Energy Technology Data Exchange (ETDEWEB)

Schmidt, I.; Veszpremi, K. [Technical University of Budapest, Department of Electrical Machines and Drives, Budapest (Hungary)

1997-12-31

In the Converter-Fed Synchronous Machine (CFSM) there is no need for forced commutation the CL and CF converters operate with line commutation, the CM is commutated by the machine voltages. This drive is applied mainly for large power and high speed controlled drives. Considering the large power, the investigation of energy-saving operation is important. As in the DC and the induction motor drives the energy-saving operation is implemented by flux control. (orig.) 6 refs.

Energy saving work of frequency controlled induction cage machine

Energy Technology Data Exchange (ETDEWEB)

Gnacinski, P. [Gdynia Maritime University, Department of Ship Electrical Power Engineering, Morska Str. 8, 81-225 Gdynia (Poland)]. E-mail: piotrg@am.gdynia.pl

2007-03-15

Energy saving work, understood as lowering the supply voltage when load torque is much less than rated, is one way of reducing power losses in an induction cage machine working with a variable load. Reduction in power losses also affects the thermal properties of an induction machine because the energy saving work allows the temperature rise of the windings to decrease. Thanks to a lower temperature of the windings, the same load torque can be carried by a machine of less rated power. The ability of energy saving work to reduce the temperature of windings depends on the thermal properties of an induction machine, which are different in the case of a machine with foreign ventilation and its own ventilation. This paper deals with the thermal effect of energy saving work on a frequency controlled induction cage machine. A comparison of the properties of a machine with its own and outside ventilation is presented. The results of the investigations are shown for a 3 kW induction cage machine with the two previously mentioned ways of ventilation: one provided with a fan placed on a shaft and the other provided with a fan driven by an auxiliary motor.

Energy saving work of frequency controlled induction cage machine

International Nuclear Information System (INIS)

Gnacinski, P.

2007-01-01

Energy saving work, understood as lowering the supply voltage when load torque is much less than rated, is one way of reducing power losses in an induction cage machine working with a variable load. Reduction in power losses also affects the thermal properties of an induction machine because the energy saving work allows the temperature rise of the windings to decrease. Thanks to a lower temperature of the windings, the same load torque can be carried by a machine of less rated power. The ability of energy saving work to reduce the temperature of windings depends on the thermal properties of an induction machine, which are different in the case of a machine with foreign ventilation and its own ventilation. This paper deals with the thermal effect of energy saving work on a frequency controlled induction cage machine. A comparison of the properties of a machine with its own and outside ventilation is presented. The results of the investigations are shown for a 3 kW induction cage machine with the two previously mentioned ways of ventilation: one provided with a fan placed on a shaft and the other provided with a fan driven by an auxiliary motor

Investigation of Reactive Power Control Effects on Flicker and Harmonics Emission of a DFIG Wind Turbine

Directory of Open Access Journals (Sweden)

Amir Nagizadeh Ghoogdareh

2013-01-01

Full Text Available One of the most important power quality aspects in wind farms is voltage fluctuation or flicker which should be investigated due to the nature of wind speed variations. These variations result in power and voltage fluctuations at the load bus. Moreover, the wind generation systems may be assumed as a harmonics source because of their power electronic converters. There are numerous factors that affect flicker and harmonic emission of grid-connected wind turbines during continuous operation, such as wind characteristics (e.g. mean wind speed, turbulence intensity, type of generator and grid conditions (e.g. short circuit capacity, grid impedance angle. In this paper, an IEC based flickermeter is first modeled and then a variable speed wind turbine has been simulated by Matlab/Simulink software. The flicker and harmonics emissions of wind turbines equipped with DFIG during continuous operation and using output reactive control are investigated. The simulation results show that control of wind turbine output reactive power is an effective means for flicker mitigation during continuous operation. However, there should be a compromise between flicker reduction and harmonics level increase to enhance the whole power quality of wind turbine.

Power and energy saving in buildings by distributed generation based on gas-engine systems

Energy Technology Data Exchange (ETDEWEB)

Arghandeh, R.; Amidpour, M.; Ghaffari, A. [Khaje Nasir Toosi Univ. of Technology, Tehran (Iran, Islamic Republic of). Joint Program of Energy Systems Engineering; Manchester Univ., Manchester (United Kingdom)

2008-07-01

Buildings consume high amounts of energy and produce high amounts of greenhouse gas (GHG) emissions. This paper discussed the use of gas cogeneration distributed generation (DG) technologies as a means of reducing energy consumption from buildings as well as energy losses from transmission lines in Iran. Energy sources and power generation systems were reviewed, and the economical benefits and energy savings resulting from the use of cogeneration systems were outlined. Actual rates of electricity consumption for Iran were estimated. Building power consumption was divided into the following 6 major sections: (1) lighting, (2) home appliances, (3) restaurant and cooking devices, (4) sports facilities, (5) utilities, and (6) electronics. Energy consumption criteria (ECC) and daily consumption charts (DCC) were used to plan and design the cogeneration systems. Energy balances, capital costs, and investment rates of return (IRR) were then calculated for 2 scenarios for a sample building. Results of the study showed that gas engine combined heat and power (CHP) DG systems are a reliable and economic technology for reducing energy consumption in buildings. The IRR of the CHP DG system for the sample building was achieved in 1 year. 13 refs., 10 tabs., 11 figs.

Prospects for future uranium savings through LWRs with high performance cores

International Nuclear Information System (INIS)

Mochida, T.; Yamamoto, T.; Sasaki, M.; Matsuura, H.; Ueji, M.; Murata, T.; Kanda, K.; Oka, Y.; Kondo, S.

1995-01-01

Since 1986, Nuclear Power Engineering Cooperation (NUPEC) has been studying four types of LWR high performance core concepts (i.e., the uranium saving core I (USC-I), the uranium saving core II (USC-II), the high moderation core (HMC) and the low moderation core (LMC)), which aim at improvement of uranium and plutonium utilization. After the evaluation of fundamental core performance and uranium and plutonium material balance for each reactor, potential uranium savings with different reactor strategies are evaluated for the Japanese scenario with assumption of the growth of future nuclear power plant generation, annual reprocessing capacity and schedules for the introduction of high performance core. At 2030, about 3-6% savings in uranium demand are expected by USC-I or USC-II strategy, while about 14% savings by HMC strategy and about 8% by LMC strategy. (author)

A new islanding detection technique for multiple mini hydro based on rate of change of reactive power and load connecting strategy

International Nuclear Information System (INIS)

Laghari, J.A.; Mokhlis, H.; Bakar, A.H.A.; Karimi, M.

2013-01-01

Highlights: • The requirement of DG interconnection with existing power system is discussed. • Various islanding detection techniques are discussed with their merits and demerits. • New islanding detection strategy is proposed for multiple mini hydro type DGs. • The proposed strategy is based on dq/dt and load connecting strategy. • The effectiveness of strategy is verified on various other cases. - Abstract: The interconnection of distributed generation (DG) into distribution networks is undergoing a rapid global expansion. It enhances the system’s reliability, while simultaneously reduces pollution problems related to the generation of electrical power. To fully utilize the benefits of DGs, certain technical issues need to be addressed. One of the most important issues in this context is islanding detection. This paper presents a new islanding detection technique that is suitable for multiple mini-hydro type DG units. The proposed strategy is based on the rate of change of reactive power and load connecting strategy to detect islanding within the system. For a large power mismatch, islanding is detected by rate of change of reactive power only. However, for a close power mismatch, the rate of change of reactive power initiates a load connecting strategy, which in turn alters the load on the distribution network. This load variation in the distribution network causes a variation in the rate of change of reactive power, which is utilized to distinguish islanding and other events. The simulation results show that the proposed strategy is effective in detecting islanding occurrence in a distribution network

78 FR 63177 - Order on Voluntary Remand and Clarifying Policy on Filing of Reactive Power Service Rate...

Science.gov (United States)

2013-10-23

... the obligation to follow a voltage schedule.'' \\19\\ The Commission distinguished Hot Spring Power Co..., to explore the mechanics of public utilities filing reactive power rate schedules for which there is...'' jurisdictional service and, accordingly, must be filed for Commission review); Sulphur Springs Valley Elec. Coop...

Comparisons of PRD [power-reactivity-decrements] components for various EBR-II configurations

International Nuclear Information System (INIS)

Meneghetti, D.; Kucera, D.A.

1986-01-01

Comparison of detailed calculations of contributions by region and component of the power-reactivity-decrements (PRD) for four differing loading configurations of the Experimental Breeder Reactor-II (EBR-II) are given. The linear components and Doppler components are calculated. The non-linear (primarily subassembly bowing) components are deduced by differences relative to measured total PRD values. Variations in linear components range from about 10% to as much as about 100% depending upon the component. The deduced non-linear components differ both in magnitude and sign as functions of reactor power. Effects of differing assumptions of the nature of the fuel-to-clad interactions upon the PRD components are also calculated

Who's in the business of saving lives?

Science.gov (United States)

Lee Chang, Pepe

2006-10-01

There are individuals, including children, dying needlessly in poverty-stricken third world countries. Many of these deaths could be prevented if pharmaceutical companies provided the drugs needed to save their lives. Some believe that because pharmaceutical companies have the power to save lives, and because they can do so with little effort, they have a special obligation. I argue that there is no distinction, with respect to obligations and responsibilities, between pharmaceutical companies and other types of companies. As a result, to hold pharmaceutical companies especially responsible for saving lives in third world countries is unjustified.

A Novel Sensor Platform Matching the Improved Version of IPMVP Option C for Measuring Energy Savings

OpenAIRE

Tseng, Yen-Chieh; Lee, Da-Sheng; Lin, Cheng-Fang; Chang, Ching-Yuan

2013-01-01

It is easy to measure energy consumption with a power meter. However, energy savings cannot be directly computed by the powers measured using existing power meter technologies, since the power consumption only reflects parts of the real energy flows. The International Performance Measurement and Verification Protocol (IPMVP) was proposed by the Efficiency Valuation Organization (EVO) to quantify energy savings using four different methodologies of A, B, C and D. Although energy savings can be...

Real-Time Control of Active and Reactive Power for Doubly Fed Induction Generator (DFIG-Based Wind Energy Conversion System

Directory of Open Access Journals (Sweden)

Aman Abdulla Tanvir

2015-09-01

Full Text Available This paper presents the modeling, rapid control prototyping, and hardware-in-the-loop testing for real-time simulation and control of a grid-connected doubly fed induction generator (DFIG in a laboratory-size wind turbine emulator for wind energy conversation systems. The generator is modeled using the direct-quadrature rotating reference frame circuit along with the aligned stator flux, and the field-oriented control approach is applied for independent control of the active and reactive power and the DC-link voltage at the grid side. The control of the active, reactive power and the DC-link voltage are performed using a back-to-back converter at sub- and super-synchronous as well as at variable speeds. The control strategy is experimentally validated on an emulated wind turbine driven by the Opal-RT real-time simulator (OP5600 for simultaneous control of the DC-link voltage, active and reactive power.

Coordination of voltage and reactive power control in the extra high voltage substations based on the example of solutions applied in the national power system

Directory of Open Access Journals (Sweden)

Dariusz Kołodziej

2012-06-01

Full Text Available This paper presents examples of coordination between automatic voltage and reactive power control systems (ARST covering adjacent and strongly related extra high voltage substations. Included are conclusions resulting from the use of these solutions. The Institute of Power Engineering, Gdańsk Division has developed and deployed ARST systems in the national power system for a dozen or so years.

Power quality in electric distribution systems

International Nuclear Information System (INIS)

Mohamed, A.A.S.

2005-01-01

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

Energy-Saving RAM-Power Tap

Science.gov (United States)

Bruner, Alan Roy

1987-01-01

Reverse-flow HEXFET(R) minimizes voltage drop and power dissipation. HEXFET(R) scheme reduces voltage drop by approximately 80 percent. Design for power tap for random-access memory (RAM) has potential application in digital systems.

Distributed control of hybrid AC microgrids with dynamic active and reactive power capacity tuning

DEFF Research Database (Denmark)

Nutkani, Inam Ullah; Loh, Poh Chiang; Blaabjerg, Frede

2012-01-01

Microgrids comprise of emerging generation technologies such as fuel cell, solar PV, wind turbine generator, storage and loads. They can, in principle, operate at different voltages and frequencies. Tying them either to the mains grid or among themselves would certainly require some interlinking...... power converters, whose control should preferably be done autonomously without demanding communication links. This paper proposes distributed control for power management between two Microgrids interlinked through inverters. The control scheme aims to reduce the reactive power loading stress on DERs...... and also allows active power transfer from overloaded grid to under- loaded grid. The performance of proposed control has been verified in simulation and through a scaled-down experimental system....

District energy-saving visions for Town of Towa; Towa machi chiiki sho energy vision

Energy Technology Data Exchange (ETDEWEB)

NONE

2001-02-01

The energy-saving visions are drawn for Town of Towa, Iwate Pref., to promote energy saving and abatement of gas emissions which cause global warming. The priority projects in the energy-saving visions include introduction of energy-saving type vehicles, houses/buildings, illuminators; introduction of solar energy utilization systems and alternative energy (e.g., wood, wastes from domestic animals and microhydroelectric power generation); and monitoring/observation of energy consumption situations and energy-saving education. The energy-saving target is set at 3,120kL as crude oil. The energy-saving activities studied for the administrative and public sectors include introduction of energy-saving type vehicles and buildings; introduction of solar energy utilization systems (for roads and public facilities when they are replaced) and microhydroelectric power generation; and monitoring/observation of energy consumption situations and energy-saving education. The energy-saving target is set at 80kL as crude oil. (NEDO)

Fuel and power resources based on energy-saving technologies and technical means in agriculture

Directory of Open Access Journals (Sweden)

A. V. Tikhomirov

2015-01-01

Full Text Available The state and efficiency of the use of the energy supply systems in agriculture were analyzed. It is demonstrated that grids and power equipment deterioration exceeds 30 percent, and fuel volume-efficiency ratio is not more than 35 percent in this sector. A considerable part of the country territory (mainly the northern one does not have centralized power supply. Decentralized cogeneration systems with extensive use of renewable energy sources and local energy recourses are highly efficient for this part. A necessity of development of methodology and recommendations for the selection of efficient systems and technical means of power supply to agricultural enterprises was substantiated with due consideration of their location, load intensity and distance from centralized grids. The most important indication of energy efficiency is energy intensity of products and energy inputs share in the production cost. Reserves for energy saving including the development of energy-efficient technologies and technical means, some of which have already been developed (equipment for lighting, microclimate, primary treatment and storage of products, disinfection or are at the completion stage were presented. Their implementation in agricultural production will make it possible to raise considerably the efficiency of the use of fuel and power resources and to reduce energy consumption. The conditions in which the use of decentralized power supply systems is most efficient were educed. The characteristics of related equipment and the specifics of its use at agricultural enterprises are described. The proposal and priority actions for the development and upgrading of power supply systems for agriculture have been elaborated.

Study on offshore wind farm integration mode and reactive power compensation

Energy Technology Data Exchange (ETDEWEB)

Bian, Xiaoyan; Hong, Lijun; Fu, Yang [Shanghai Univ. of Electrical Power (China). Power and Automation Engineering Dept.

2013-07-01

Two typical offshore wind farm grid-connected modes are introduced and dynamic characteristics under their modes are compared from the simulation by PSS/E. The result shows that offshore wind farm with VSC-HVDC has better dynamic characteristics on fault isolation, reactive power compensation, and fault ride through ability. In addition, STATCOM has been applied to the offshore wind farm, the simulation results indicates that it can improve the bus voltage stability in fault and maintain the voltage level under a small perturbation.

Demand response strategy management with active and reactive power incentive in the smart grid: a two-level optimization approach

Directory of Open Access Journals (Sweden)

Ryuto Shigenobu

2017-05-01

Full Text Available High penetration of distributed generators (DGs using renewable energy sources (RESs is raising some important issues in the operation of modern po­wer system. The output power of RESs fluctuates very steeply, and that include uncertainty with weather conditions. This situation causes voltage deviation and reverse power flow. Several methods have been proposed for solving these problems. Fundamentally, these methods involve reactive power control for voltage deviation and/or the installation of large battery energy storage system (BESS at the interconnection point for reverse power flow. In order to reduce the installation cost of static var compensator (SVC, Distribution Company (DisCo gives reactive power incentive to the cooperating customers. On the other hand, photovoltaic (PV generator, energy storage and electric vehicle (EV are introduced in customer side with the aim of achieving zero net energy homes (ZEHs. This paper proposes not only reactive power control but also active power flow control using house BESS and EV. Moreover, incentive method is proposed to promote participation of customers in the control operation. Demand response (DR system is verified with several DR menu. To create profit for both side of DisCo and customer, two level optimization approach is executed in this research. Mathematical modeling of price elasticity and detailed simulations are executed by case study. The effectiveness of the proposed incentive menu is demonstrated by using heuristic optimization method.

A novel islanding detection scheme for synchronous distributed generation using rate of change of exciter voltage over reactive power at DG-Side

DEFF Research Database (Denmark)

Rostami, Ali; Bagheri, Marzieh; Naderi, Seyed Behzad

2017-01-01

, the reactive power at DG-side and exciter voltage parameters are selected. The performance of the proposed method is investigated in MATLAB/Simulink software on a sample network in the presence of synchronous diesel-generator. The simulation results indicate that the proposed method is capable to detect all......Penetration of distributed generation (DG) in distribution networks is rapidly increasing. DGs' application enhances system's reliability and power quality. However, along their benefits, there are some issues. One of the most important issues of DGs' application is the islanding. This paper...... of the synchronous generator. Therefore, due to lack of inertia, response of these parameters to small changes is faster than the other passive parameters such as frequency. However, the sensitivity of reactive power at the DG-side and the exciter voltage is much more than reactive power and voltage of the load. So...

Containment and Consensus-based Distributed Coordination Control for Voltage Bound and Reactive Power Sharing in AC Microgrid

DEFF Research Database (Denmark)

Han, Renke; Meng, Lexuan; Ferrari-Trecate, Giancarlo

2017-01-01

This paper offers a highly flexible and reliable control strategy to achieve voltage bounded regulation and accurate reactive power sharing coordinately in AC Micro-Grids. A containment and consensus-based distributed coordination controller is proposed, by which each output voltage magnitude can...... be bounded within a reasonable range and the accurate reactive power sharing among distributed generators can be also achieved. Combined with the two proposed controllers and electrical part of the AC Micro-Grid, a small signal model is fully developed to analyze the sensitivity of different control...... parameters. The effectiveness of the proposed controller in case of load variation, communication failure, plug-and-play capability are verified by the experimental setup as an islanded Micro-Grid....

Portable digital reactivity meter for power reactors

Energy Technology Data Exchange (ETDEWEB)

Steffen, G [Nuklear-Ingenieur Service G.m.b.H., Hanau (Germany, F.R.)

1977-07-01

A digital reactivity meter has been developed, which can be used for all kinds of kinetic reactivity measurements in PWR's and BWR's. The input signals may be supplied by standard neutron detectors of the reactor. The hardware configuration consists of a minicomputer with ADC and DAC, a 'Silent' terminal and a high speed paper tape reader/punch. It is easily transportable. The reactivity meter solves the inverse kinetics equations for 6 delayed neutron groups, simultaneously for up to 8 logarithmic or linear neutron flux signals. It has been successfully tested at Biblis A PWR and the KRB BWR.

A Data-Driven Stochastic Reactive Power Optimization Considering Uncertainties in Active Distribution Networks and Decomposition Method

DEFF Research Database (Denmark)

Ding, Tao; Yang, Qingrun; Yang, Yongheng

2018-01-01

To address the uncertain output of distributed generators (DGs) for reactive power optimization in active distribution networks, the stochastic programming model is widely used. The model is employed to find an optimal control strategy with minimum expected network loss while satisfying all......, in this paper, a data-driven modeling approach is introduced to assume that the probability distribution from the historical data is uncertain within a confidence set. Furthermore, a data-driven stochastic programming model is formulated as a two-stage problem, where the first-stage variables find the optimal...... control for discrete reactive power compensation equipment under the worst probability distribution of the second stage recourse. The second-stage variables are adjusted to uncertain probability distribution. In particular, this two-stage problem has a special structure so that the second-stage problem...

Locomotive energy savings possibilities

Directory of Open Access Journals (Sweden)

Leonas Povilas LINGAITIS

2009-01-01

Full Text Available Economic indicators of electrodynamic braking have not been properly estimated. Vehicles with alternative power trains are transitional stage between development of pollution- free vehicles. According to these aspects the investigation on conventional hybrids drives and their control system is carried out in the article. The equation that allows evaluating effectiveness of regenerative braking for different variants of hybrid drive are given. Presenting different types of locomotive energy savings power systems, which are using regenerative braking energy any form of hybrid traction vehicles systems, circuit diagrams, electrical parameters curves.

Voltage stability in low voltage microgrids in aspects of active and reactive power demand

Directory of Open Access Journals (Sweden)

Parol Mirosław

2016-03-01

Full Text Available Low voltage microgrids are autonomous subsystems, in which generation, storage and power and electrical energy consumption appear. In the paper the main attention has been paid to the voltage stability issue in low voltage microgrid for different variants of its operation. In the introduction a notion of microgrid has been presented, and also the issue of influence of active and reactive power balance on node voltage level has been described. Then description of voltage stability issue has been presented. The conditions of voltage stability and indicators used to determine voltage stability margin in the microgrid have been described. Description of the low voltage test microgrid, as well as research methodology along with definition of considered variants of its operation have been presented further. The results of exemplary calculations carried out for the daily changes in node load of the active and reactive power, i.e. the voltage and the voltage stability margin indexes in nodes have been presented. Furthermore, the changes of voltage stability margin indexes depending on the variant of the microgrid operation have been presented. Summary and formulation of conclusions related to the issue of voltage stability in microgrids have been included at the end of the paper.

Traffic-aware Elastic Optical Networks to leverage Energy Savings

DEFF Research Database (Denmark)

Turus, Ioan; Fagertun, Anna Manolova; Dittmann, Lars

2014-01-01

Because of the static nature of the deployed optical networks, large energy wastage is experienced today in production networks such as Telecom networks . With power-adaptive optical interfaces and suitable grooming procedures, we propose the design of more energy efficient transport networks....... Optical network reconfigurations are performed by GMPLS node controllers according to monitored traffic information. The investigated energy reduction strategies are simulated on two large scale transport networks (DT17 and COST37). The results show that the energy savings obtained by these strategies......-Europea n COST37 network, for both symbol-rate and modulation format adaptations significant savings are obtained . Mixed adaptation (jointly performing symbol-rate and modulation format adaptations) used together with optical grooming allows up to 4 4 % and 4 7 % power savings in DT17 and COST37 networks...

Solving multiobjective optimal reactive power dispatch using modified NSGA-II

Energy Technology Data Exchange (ETDEWEB)

Jeyadevi, S.; Baskar, S.; Babulal, C.K.; Willjuice Iruthayarajan, M. [Department of Electrical and Electronics Engineering, Thiagarajar College of Engineering, Madurai, Tamilnadu 625 015 (India)

2011-02-15

This paper addresses an application of modified NSGA-II (MNSGA-II) by incorporating controlled elitism and dynamic crowding distance (DCD) strategies in NSGA-II to multiobjective optimal reactive power dispatch (ORPD) problem by minimizing real power loss and maximizing the system voltage stability. To validate the Pareto-front obtained using MNSGA-II, reference Pareto-front is generated using multiple runs of single objective optimization with weighted sum of objectives. For simulation purposes, IEEE 30 and IEEE 118 bus test systems are considered. The performance of MNSGA-II, NSGA-II and multiobjective particle swarm optimization (MOPSO) approaches are compared with respect to multiobjective performance measures. TOPSIS technique is applied on obtained non-dominated solutions to determine best compromise solution (BCS). Karush-Kuhn-Tucker (KKT) conditions are also applied on the obtained non-dominated solutions to substantiate a claim on optimality. Simulation results are quite promising and the MNSGA-II performs better than NSGA-II in maintaining diversity and authenticates its potential to solve multiobjective ORPD effectively. (author)

Rated power factor and excitation system of large turbine generator

International Nuclear Information System (INIS)

Tokumitsu, Iwao; Watanabe, Takashi; Banjou, Minoru.

1979-01-01

As for the rated power factor of turbine generators for thermal power stations, 90% has been adopted since around 1960. On the other hand, power transmission system has entered 500 kV age, and 1,000 kV transmission is expected in the near future. As for the supply of reactive power from thermal and nuclear turbine generators, the necessity of supplying leading reactive power has rather increased. Now, the operating power factor of thermal and nuclear generators becomes 96 to 100% actually. As for the excess stability of turbine generators owing to the strengthening of transmission system and the adoption of super-high voltage, the demand of strict conditions can be dealt with by the adoption of super-fast response excitation system of thyristor shunt winding self exciting type. The adoption of the turbine generators with 90 to 95% power factor and the adoption of the thyristor shunt winding self exciting system were examined and evaluated. The rated power factor of generators, excitation system and economy of adopting these systems are explained. When the power factor of generators is increased from 0.9 to 0.95, about 6% of saving can be obtained in the installation cost. When the thyristor shunt winding self excitation is adopted, it is about 10% more economical than AC excitation. (Kako, I.)

An optimal reactive power control strategy for a DFIG-based wind farm to damp the sub-synchronous oscillation of a power system

DEFF Research Database (Denmark)

Zhao, Bin; Li, Hui; Wang, Mingyu

2014-01-01

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 capaciti...

Reactivity estimation during a reactivity-initiated accident using the extended Kalman filter

International Nuclear Information System (INIS)

Busquim e Silva, R.; Marques, A.L.F.; Cruz, J.J.; Shirvan, K.; Kazimi, M.S.

2015-01-01

Highlights: • The EKF is modeled using sophisticate strategies to make the algorithm robust and accurate. • For a supercritical reactor under RIA, the EKF presents better results compared to IPK method independent of magnitude of the noise loads. • A sensitivity for five distinct carry-over effects indicates that the EKF is less sensitive to the different set of noise. • Although the P3D/R5 simulates the reactivity using a spatial kinetics method, the use of PKRE to model the EKF provides accurate results. • The reactivity’s standard deviation is higher for the IKF method. • Under HZP (slow power response) the IPK reactivity varies widely from positive to negative values (add extra difficulty to controlling the supercritical reactor): the EKF method does not have similar behavior under the same conditions (better controlling the operation). - Abstract: This study implements the extended Kalman filter (EKF) to estimate the nuclear reactor reactivity behavior under a reactivity-initiated accident (RIA). A coupled neutronics/thermal hydraulics code PARCS/RELAP5 (P3D/R5) simulates a control rod assembly ejection (CRE) on a traditional 2272 MWt PWR to generate the reactor power profile. A MATLAB script adds random noise to the simulated reactor power. For comparison, the inverse point kinetics (IPK) deterministic method is also implemented. Three different cases of CRE are simulated and the EKF, IPK and the P3D/R5 reactivity are compared. It was found that the EKF method presents better results compared to the IPK method. Furthermore, under a RIA due to small reactivity insertion and slow power response, the IPK reactivity varies widely from positive to negative, which may add extra difficulty to the task of controlling a supercritical reactor. This feature is also confirmed by a sensitivity analysis for five different noise loads and three distinct noise measurements standard deviations (SD)

Effect of reactivity insertion rate on peak power and temperatures in swimming pool type research reactor

International Nuclear Information System (INIS)

Khan, L.A.; Jabbar, A.; Anwar, A.R.; Ahmad, N.

1998-01-01

It is essential to study the reactor behavior under different accidental conditions and take proper measures for its safe operation. We have studied the effect of reactivity insertion, with and without scram conditions, on peak power and temperatures of fuel, cladding and coolant in typical swimming pool type research reactor. The reactivity ranging from 1 $ to 2 $ and insertion times from 0.25 to 1 second have been considered. The computer code PARET has been used and results are presented in this article. (author)

New York Power Authority`s energy-efficient refigerator program for the New York City Housing Authority - savings evaluation

Energy Technology Data Exchange (ETDEWEB)

Pratt, R.G.; Miller, J.D.

1997-09-01

The New York Power Authority (NYPA) and the New York City Housing Authority (NYCHA) are replacing refrigerators in New York City public housing with new, highly energy-efficient models over a five-year period. This report describes the analysis of the energy cost savings achieved through the replacement of 20,000 refrigerators in 1996, the first year of the NYPA/NYCHA program. The NYPA/NYCHA project serves as the lynchpin of a larger program designed to offer energy-efficient appliances to housing authorities across the country. The national program is a partnership between the U.S. Department of Energy (DOE) and the Consortium for Energy Efficiency (CEE). Starting with the 1997 refrigerator contract, this program invites other housing authorities to join NYPA in its volume purchase of energy-efficient refrigerators, at the same price and terms available to NYPA. Through these volume purchases, DOE`s ENERGY STAR{reg_sign} Partnerships program hopes to encourage appliance manufacturers to bring more efficient appliances to the market and to provide volume purchasers with the per-unit price savings of a bulk purchaser. DOE asked the Pacific Northwest National Laboratory (PNNL) to establish a protocol for evaluating the savings achieved with the NYPA refrigerators. That protocol is summarized in this report.

Effects of Radial Reflector Composition on Core Reactivity and Peak Power

International Nuclear Information System (INIS)

Park, Sang Yoon; Lee, Kyung Hoon; Song, Jae Seung

2007-10-01

The effects of radial SA-240 alloy shroud on core reactivity and peak power are evaluated. The existence of radial SA-240 alloy shroud makes reflector water volume decrease, so the thermal absorption cross section of radial reflector is lower than without SA-240 alloy shroud case. Finally, the cycle length is increased from 788 EFPD to 845 EFPD and the peak power is decreased from 1.66 to 1.49. In the case of without SA-240 alloy shroud, a new core loading pattern search has been performed. For the guarantee of the same equivalent cycle length of with SA-240 alloy shroud case, the enrichment of U-235 should be increased from 4.22 w/o to 4.68 w/o. The nuclear key safety parameters of new core loading pattern have been calculated and recorded for the future

Effects of Radial Reflector Composition on Core Reactivity and Peak Power

Energy Technology Data Exchange (ETDEWEB)

Park, Sang Yoon; Lee, Kyung Hoon; Song, Jae Seung

2007-10-15

The effects of radial SA-240 alloy shroud on core reactivity and peak power are evaluated. The existence of radial SA-240 alloy shroud makes reflector water volume decrease, so the thermal absorption cross section of radial reflector is lower than without SA-240 alloy shroud case. Finally, the cycle length is increased from 788 EFPD to 845 EFPD and the peak power is decreased from 1.66 to 1.49. In the case of without SA-240 alloy shroud, a new core loading pattern search has been performed. For the guarantee of the same equivalent cycle length of with SA-240 alloy shroud case, the enrichment of U-235 should be increased from 4.22 w/o to 4.68 w/o. The nuclear key safety parameters of new core loading pattern have been calculated and recorded for the future.

Implementation of energy-saving policies in China: How local governments assisted industrial enterprises in achieving energy-saving targets

International Nuclear Information System (INIS)

Zhao, Xiaofan; Li, Huimin; Wu, Liang; Qi, Ye

2014-01-01

Local governments have replaced the national ministries that are in charge of various industries to become the primary implementer of energy-saving policies in China since 2000. This paper employs a case study-based approach to demonstrate the significance of local governments’ policy measures in assisting industrial enterprises with energy-saving activities in China. Based on the longitudinal case of the Jasmine Thermal Electric Power Company, this paper hypothesizes that sub-national governments have played a major role in implementing energy-saving policies in China since the 11th Five-year-plan period. A wide range of provincial and municipal agencies collaborated in implementing five types of policy measures – informational policy, skill building, improved enforcement of central directives, price adjustment, and funding – that reduced barriers to energy saving and motivated active pursuit of energy-saving activities at industrial enterprises. The case study demonstrates how an enterprise and local governments work together to achieve the enterprise's energy-saving target. The authors will investigate the hypothesis of this paper in the context of multiple case studies that they plan to undertake in the future. - Highlights: • We employ a case study-based approach to study policy implementation in China. • Local governments have played a major role in implementing energy-saving policies. • Local public agencies collaborated in implementing five types of policy measures. • Local policy measures reduced barriers to energy saving at industrial enterprises. • Enterprises and local governments work together to achieve energy-saving targets

Synthesis and processing of composites by reactive metal penetration

Energy Technology Data Exchange (ETDEWEB)

Loehman, R.E.; Ewsuk, K.G. [Sandia National Laboratories, Albuquerque, NM (United States); Tomsia, A.P. [Pask Research and Engineering, Berkeley, CA (United States)] [and others

1995-05-01

Ceramic-metal composites are being developed because their high stiffness-to weight ratios, good fracture toughness, and variable electrical and thermal properties give them advantages over more conventional materials. However, because ceramic-metal composite components presently are more expensive than monolithic materials, improvements in processing are required to reduce manufacturing costs. Reactive metal penetration is a promising new method for making ceramic- and metal-matrix composites that has the advantage of being inherently a net-shape process. This technique, once fully developed, will provide another capability for manufacturing the advanced ceramic composites that are needed for many light-weight structural and wear applications. The lower densities of these composites lead directly to energy savings in use. Near-net-shape fabrication of composite parts should lead to additional savings because costly and energy intensive grinding and machining operations are significantly reduced, and the waste generated from such finishing operations is minimized. The goals of this research program are: (1) to identify feasible compositional systems for making composites by reactive metal penetration; (2) to understand the mechanism(s) of composite formation by reactive metal penetration; and (3) to learn how to control and optimize reactive metal penetration for economical production of composites and composite coatings.

Design of sensor energy-saving controller for photovoltaic power generation%光伏发电中的传感器节能控制器设计

Institute of Scientific and Technical Information of China (English)

云彩霞; 李丽芬; 蔡小庆; 刘晨

2017-01-01

传感器储能性能较弱，导致设计出的光伏发电中的传感器节能控制器网络延迟较长、节能效果不理想。因而，设计一种新型光伏发电中的传感器节能控制器，其对供电电路、无线通信芯片和太阳光传感器芯片进行重点设计。nRF905无线通信芯片对控制器中各设备、电路、元件之间的数据通信进行监控，保障节能效果、缩短网络延迟。供电电路为控制器的节能工作供应电能、优化太阳光光强的能量转化。优化后的太阳光能量，将通过太阳光传感器中的TSL2678芯片太阳光进行参数提取和分析，输出太阳能最佳采集方位和该方位的太阳光光强，实现光伏发电的最优节能。控制器软件设计部分给出了控制器的节能控制流程。分析实验结果可知，所设计的控制器具有网络延迟短、节能效果好的特点。%Since the sensor energy⁃saving controller for the photovoltaic power generation has long network latency and un⁃satisfied energy⁃saving effect due to the poor energy storage performance of the sensor,a new sensor energy⁃saving controller for the photovoltaic power generation was designed,and its power supply circuit,wireless communication chip and solar sensor chip were designed emphatically. The wireless communication chip NRF905 is used to monitor the data communication among each device,circuit and component in the controller to ensure the energy⁃saving effect and shorten the network latency. The power supply circuit supplies the electric energy for the energy⁃saving work of the controller,and optimizes the energy conversion of so⁃lar light. The parameters of the optimized solar light energy are extracted and analyzed through the chip TSL2678 in the solar light sensor,which outputs the optimal acquisition orientation of the solar energy and its intensity to realize the optimal energy saving of the photovoltaic power generation. The energy⁃saving

Mitigating Space Weather Impacts on the Power Grid in Real-Time: Applying 3-D EarthScope Magnetotelluric Data to Forecasting Reactive Power Loss in Power Transformers

Science.gov (United States)

Schultz, A.; Bonner, L. R., IV

2017-12-01

Current efforts to assess risk to the power grid from geomagnetic disturbances (GMDs) that result in geomagnetically induced currents (GICs) seek to identify potential "hotspots," based on statistical models of GMD storm scenarios and power distribution grounding models that assume that the electrical conductivity of the Earth's crust and mantle varies only with depth. The NSF-supported EarthScope Magnetotelluric (MT) Program operated by Oregon State University has mapped 3-D ground electrical conductivity structure across more than half of the continental US. MT data, the naturally occurring time variations in the Earth's vector electric and magnetic fields at ground level, are used to determine the MT impedance tensor for each site (the ratio of horizontal vector electric and magnetic fields at ground level expressed as a complex-valued frequency domain quantity). The impedance provides information on the 3-D electrical conductivity structure of the Earth's crust and mantle. We demonstrate that use of 3-D ground conductivity information significantly improves the fidelity of GIC predictions over existing 1-D approaches. We project real-time magnetic field data streams from US Geological Survey magnetic observatories into a set of linear filters that employ the impedance data and that generate estimates of ground level electric fields at the locations of MT stations. The resulting ground electric fields are projected to and integrated along the path of power transmission lines. This serves as inputs to power flow models that represent the power transmission grid, yielding a time-varying set of quasi-real-time estimates of reactive power loss at the power transformers that are critical infrastructure for power distribution. We demonstrate that peak reactive power loss and hence peak risk for transformer damage from GICs does not necessarily occur during peak GMD storm times, but rather depends on the time-evolution of the polarization of the GMD's inducing fields

Mass savings domain of plasma propulsion for LEO to GEO transfer

International Nuclear Information System (INIS)

Choueiri, E.Y.; Kelly, A.J.; Jahn, R.G.

1993-01-01

A parametric model is used to study the mass savings of plasma propulsion over advanced chemical propulsion for lower earth orbit (LEO) to geosynchronous orbit (GEO) transfer. Such savings are characterized by stringent requirements of massive payloads (O(10) metric tons) and high power levels (O(100) kW). Mass savings on the order of the payload mass are possible but at the expense of longer transfer times (8--20 months). Typical of the savings domain is the case of a self-field magnetoplasmadynamic (MPD) thruster running quasi-steadily, at an I s of 2000 s, with 600 kW of input power, raising a 50 metric ton satellite in 270 days. The initial mass at LEO will be 65 tons less than a 155 ton LO 2 /LH 2 advanced chemical high thrust spacecraft. An optimum I s can only be found if the cost savings associated with mass savings are counterbalanced by the cost losses incurred by longer transfer times. A simplistic cost model that illustrates the overall trends in the optimization yielded an optimum I s of about 2200 s for a cost effective baseline MPD system

Saving electricity in a hurry. Dealing with temporary shortfalls in electricity supplies

Energy Technology Data Exchange (ETDEWEB)

none

2005-07-01

Blackouts are normally the result of imbalances in electricity supply and demand. A brief blackout is mostly an inconvenience. But persistent shortfalls ? those lasting days, weeks, or months ? can cause economic disruption and danger to human life in our technology-rich societies. Saving Electricity in a Hurry describes some of the recent power shortfalls, from Norway to New Zealand, from Tokyo to Arizona and the policies these regions used to quickly reduce their power consumption. How did the whole country of Sweden cut its power consumption by 4% in only three days? How did California save 14% in only a few months? While the temporary shortfalls in electricity supplies described in this book are relatively rare events, they disproportionately shape future energy policies. Saving Electricity in a Hurry shows that countries can quickly reduce electricity consumption without harming the economy as much as blackouts or unplanned curtailments. The strategies are diverse, unique and often surprisingly cheap. They include mass media campaigns ? where a good joke can save a Megawatt ? improvements in equipment efficiency and quickly adjusting electricity prices. This book explains how California replaced a million traffic signals with energy-saving models, how millions of Tokyo residents raised their thermostat settings, and how New Zealanders took shorter showers, all quickly enough to help avoid imminent blackouts. Finally, it connects these policies to the traditional goal of ?saving electricity slowly?.

Reactive Power Control of Single-Stage Three-Phase Photovoltaic System during Grid Faults Using Recurrent Fuzzy Cerebellar Model Articulation Neural Network

Directory of Open Access Journals (Sweden)

Faa-Jeng Lin

2014-01-01

Full Text Available This study presents a new active and reactive power control scheme for a single-stage three-phase grid-connected photovoltaic (PV system during grid faults. The presented PV system utilizes a single-stage three-phase current-controlled voltage-source inverter to achieve the maximum power point tracking (MPPT control of the PV panel with the function of low voltage ride through (LVRT. Moreover, a formula based on positive sequence voltage for evaluating the percentage of voltage sag is derived to determine the ratio of the injected reactive current to satisfy the LVRT regulations. To reduce the risk of overcurrent during LVRT operation, a current limit is predefined for the injection of reactive current. Furthermore, the control of active and reactive power is designed using a two-dimensional recurrent fuzzy cerebellar model articulation neural network (2D-RFCMANN. In addition, the online learning laws of 2D-RFCMANN are derived according to gradient descent method with varied learning-rate coefficients for network parameters to assure the convergence of the tracking error. Finally, some experimental tests are realized to validate the effectiveness of the proposed control scheme.

Energy savings in dynamic and resilient optical networks based on traffic-aware strategies

DEFF Research Database (Denmark)

Turus, Ioan; Fagertun, Anna Manolova; Dittmann, Lars

2014-01-01

andconnections. Results show that symbol-rateadaptation provides high savings for unprotected scenarios (37% energy savings w.r.t. unprotected Baseline), while for theprotected scenarios better results are obtained for modulationformat adaptation which includes sleep-mode (57.1% energysavings w.r.t. protected...... Baseline). Moreover, compared to theBaseline scenarios the Mixed adaptation, combining bothsymbol-rate and modulation format, is the most power-efficientstrategy providing 39% energy savings for unprotected scenarioand 70% energy savings for dedicated protection scenario.......An analysis of the energy savingsis presentedwhen taking into account a complete traffic model for a one-yeartime period. Daily and weekly traffic fluctuations as well asyearly traffic growth are considered whenanalyzing the powerconsumption.Low power mode in optoelectronic devices (sleep...

Reactive power dispatch considering voltage stability with seeker optimization algorithm

Energy Technology Data Exchange (ETDEWEB)

Dai, Chaohua; Chen, Weirong; Zhang, Xuexia [The School of Electrical Engineering, Southwest Jiaotong University, Chengdu 610031 (China); Zhu, Yunfang [Department of Computer and Communication Engineering, E' mei Campus, Southwest Jiaotong University, E' mei 614202 (China)

2009-10-15

Optimal reactive power dispatch (ORPD) has a growing impact on secure and economical operation of power systems. This issue is well known as a non-linear, multi-modal and multi-objective optimization problem where global optimization techniques are required in order to avoid local minima. In the last decades, computation intelligence-based techniques such as genetic algorithms (GAs), differential evolution (DE) algorithms and particle swarm optimization (PSO) algorithms, etc., have often been used for this aim. In this work, a seeker optimization algorithm (SOA) based method is proposed for ORPD considering static voltage stability and voltage deviation. The SOA is based on the concept of simulating the act of human searching where search direction is based on the empirical gradient by evaluating the response to the position changes and step length is based on uncertainty reasoning by using a simple Fuzzy rule. The algorithm's performance is studied with comparisons of two versions of GAs, three versions of DE algorithms and four versions of PSO algorithms on the IEEE 57 and 118-bus power systems. The simulation results show that the proposed approach performed better than the other listed algorithms and can be efficiently used for the ORPD problem. (author)

Structural and optical properties of zirconia thin films deposited by reactive high-power impulse magnetron sputtering

Energy Technology Data Exchange (ETDEWEB)

Zhao, Xiaoli; Jin, Jie [Tianjin University, School of Electronic Information Engineering, Tianjin (China); Cheng, Jui-Ching, E-mail: juiching@ntut.edu.tw [Chang-Gung University, Department of Electronics, Taoyuan, Taiwan (China); Lee, Jyh-Wei [Ming Chi University of Technology, College of Materials Engineering, New Taipei City, Taiwan (China); Wu, Kuo-Hong [Chang-Gung University, Department of Electronics, Taoyuan, Taiwan (China); Lin, Kuo-Cheng; Tsai, Jung-Ruey [Asia University, Department of Photonics and Communication Engineering, Taichung, Taiwan (China); Liu, Kou-Chen, E-mail: jacobliu@mail.cgu.edu.tw [Chang-Gung University, Department of Electronics, Taoyuan, Taiwan (China)

2014-11-03

Zirconia films are deposited by reactive high power impulse magnetron sputtering (HiPIMS) technology on glass and indium-tin-oxide (ITO)/glass substrates. Preparation, microstructure and optical characteristics of the films have been studied. During deposition, the influence of the target power and duty cycle on the peak current–voltage and power density has been observed in oxide mode. Transparent thin films under different oxygen proportions are obtained on the two substrates. Atomic force microscopy measurements showed that the surface roughness of the films was lower by reactive HiPIMS than DC sputtering for all oxygen contents. The transmission and reflectance properties of differently grown zirconia films were also investigated using an ultraviolet–visible spectrophotometer. The optical transmittance of films grown on glass substrates by HiPIMS reached maximum values above 90%, which exceeded that by DC sputtering. The band edge near 5.86 eV shifted to a lower wavelength for zirconia films prepared with oxygen flow rates lower than 4.5 sccm. For the films prepared on ITO/glass substrates, the transmittance and the band gap of zirconia films were limited by ITO films; a maximum average transmittance of 84% was obtained at 4.5 sccm O{sub 2} and the energy band gap was in the range of 3.7–3.8 eV for oxygen flow rates ranging from 3.5 to 5.0 sccm. Finally, the electrical properties of zirconia films have also been discussed. - Highlights: • Zirconia films are deposited by reactive high power impulse magnetron sputtering. • Low roughness films are obtained. • Films show a high transmittance (> 90%). • Films prepared on glass have a band gap of 5.9 eV.

Loss Minimizing Operation of Doubly Fed Induction Generator Based Wind Generation Systems Considering Reactive Power Provision

DEFF Research Database (Denmark)

Baohua, Zhang; Hu, Weihao; Chen, Zhe

2014-01-01

The paper deals with control techniques for minimizing the operating loss of doubly fed induction generator based wind generation systems when providing reactive power. The proposed method achieves its goal through controlling the rotor side q-axis current in the synchronous reference frame...

Coupling/Tradeoff Analysis and Novel Containment Control for Reactive Power, Output Voltage in Islanded Micro-Grid

DEFF Research Database (Denmark)

Han, Renke; Meng, Lexuan; Guerrero, Josep M.

2016-01-01

Based on the hierarchical control structure in islanded Micro-Grid (MG) systems, the coupling/tradeoff effects in different control levels are analyzed in details. In the primary level, analyses of the coupling effects among droop control gains, line impedance differences, output reactive power...

Robust Adaptive Reactive Power Control for Doubly Fed Induction Generator

Directory of Open Access Journals (Sweden)

Huabin Wen

2014-01-01

Full Text Available The problem of reactive power control for mains-side inverter (MSI in doubly fed induction generator (DFIG is studied in this paper. To accommodate the modelling nonlinearities and inherent uncertainties, a novel robust adaptive control algorithm for MSI is proposed by utilizing Lyapunov theory that ensures asymptotic stability of the system under unpredictable external disturbances and significant parametric uncertainties. The distinguishing benefit of the aforementioned scheme consists in its capabilities to maintain satisfactory performance under varying operation conditions without the need for manually redesigning or reprogramming the control gains in contrast to the commonly used PI/PID control. Simulations are also built to confirm the correctness and benefits of the control scheme.

Literature Survey on Operational Voltage Control and Reactive Power Management on Transmission and Sub-Transmission Networks

Energy Technology Data Exchange (ETDEWEB)

Elizondo, Marcelo A.; Samaan, Nader A.; Makarov, Yuri V.; Holzer, Jesse T.; Vallem, Mallikarjuna R.; Huang, Renke; Vyakaranam, Bharat GNVSR; Ke, Xinda; Pan, Feng

2017-10-02

Voltage and reactive power system control is generally performed following usual patterns of loads, based on off-line studies for daily and seasonal operations. This practice is currently challenged by the inclusion of distributed renewable generation, such as solar. There has been focus on resolving this problem at the distribution level; however, the transmission and sub-transmission levels have received less attention. This paper provides a literature review of proposed methods and solution approaches to coordinate and optimize voltage control and reactive power management, with an emphasis on applications at transmission and sub-transmission level. The conclusion drawn from the survey is that additional research is needed in the areas of optimizing switch shunt actions and coordinating all available resources to deal with uncertain patterns from increasing distributed renewable generation in the operational time frame. These topics are not deeply explored in the literature.

Trigeneration primary energy saving evaluation for energy planning and policy development

International Nuclear Information System (INIS)

Chicco, Gianfranco; Mancarella, Pierluigi

2007-01-01

Trigeneration or combined heat, cooling and power (CHCP) is becoming an increasingly important energy option, particularly on a small-scale basis (below 1 MW e ), with several alternatives nowadays available for the cooling power production and the coupling to cogeneration systems. This paper deals with the introduction of a suitable framework for assessing the energy saving performance of trigeneration alternatives, orientated towards energy planning studies and the development of regulatory policies. In particular, a new generalized performance indicator-the trigeneration primary energy saving (TPES)-is introduced and discussed, with the aim of effectively evaluating the primary energy savings from different CHCP alternatives. The potential of the TPES indicator is illustrated through specific analyses run over different combinations of trigeneration equipment, providing numerical examples based on time-domain simulations to illustrate the dependence of the energy saving characteristics on the CHCP system configurations and equipment, as well as on the loading levels. In addition, the key aspect of adequately establishing the reference efficiencies for the conventional separate production of electrical, thermal and cooling power is addressed in detail. This aspect affects both equipment selection and potential profitability of the considered solutions under the outlook of receiving financial incentives

Energy Smart Guide to Campus Cost Savings: Today's Trends in Project Finance, Clean Fuel Fleets, Combined Heat& Power, Emissions Markets

Energy Technology Data Exchange (ETDEWEB)

2003-07-01

The Energy Smart Guide to Campus Cost Savings covers today's trends in project finance, combined heat& power, clean fuel fleets and emissions trading. The guide is directed at campus facilities and business managers and contains general guidance, contact information and case studies from colleges and universities across the country.

Saving, efficiency and management of electric sector demand

International Nuclear Information System (INIS)

Sanchez de Tembleque, L. J.

2007-01-01

Spanish economic model of development is based on energy consumption, and its main source is imported fossil fuels, which have some environmental and scarcity consequences in the mid term, among others. These problems could be reduced in two ways: economic activity reduction or energy efficiency improvement. In the presence of these possibilities, It may be desirable to bet for saving and energy efficiency, to maintain the economic development. This assignment analyzes the main available regulatory and social mechanisms to promote saving and energy efficiency in the power sector, like systems to internalize social costs in the electricity price, efficiency standards, and encourage the new saving culture. (Author) 15 refs

Reactivity control in HTR power plants with respect to passive safety system. Summary

Energy Technology Data Exchange (ETDEWEB)

Barnert, H; Kugeler, K [Forschungszentrum Juelich GmbH (Germany). Inst. fuer Sicherheitsforschung und Reaktortechnik

1996-12-01

The R and D and Demonstration of the High Temperature Reactor (HTR) is described in overview. The HTR-MODULE power plant, as the most advanced concept, is taken for the description of the reactivity control in general. The idea of the ``modularization of the core`` of the HTR has been developed as the answer on the experiences of the core melt accident at Three Miles Island. The HTR module has two shutdown systems: The ``6 rods``-system for hot shutdown at the ``18 small absorber pebbles units`` - system for cold shutdown. With respect to the definition of ``Passive Systems`` of IAEA-TECDOC-626 the total reactivity control system of the HTR-MODULE is a passive system of category D, because it is an emergency reactor shutdown system based on gravity driven rods, and devices, activated by fail-safe trip logic. But reactivity control of the HTR does not only consist of these engineered safety system but does have a self-acting stabilization by the negative temperature coefficient of the reactivity, being rather effective in reactivity control. Examples from computer calculations are presented, and, in addition, experimental results from the ``Stuck Rod Experiment`` at the AVR reactor in Juelich. On the basis of this the proposal is made that ``self-acting stabilization as a quality of the function`` should be discussed as a new category in addition to the active and passive engineered safety systems, structures and components of IAEA-TECDOC-626. The requirements for a future ``catastrophe-free`` nuclear technology are presented. In the appendix the 7th amendment of the atomic energy act of the Federal Republic of Germany, effective 28 July 94, is given. (author).

Saving more to consume more. EDF's communication ambiguities during the energy saving era

International Nuclear Information System (INIS)

Bouvier, Yves

2012-01-01

Since 1974, EDF is placed between a communication scheme imposed for energy savings and an industrial strategy of massive investment in nuclear power. In ten years, the company managed to increase households electricity consumption without advertising, due in particular to electric heating. But strong tensions were generated by this situation and led the company to develop an institutional communication to the employees and to the general public

Fuzzy-TLBO optimal reactive power control variables planning for energy loss minimization

International Nuclear Information System (INIS)

Moghadam, Ahmad; Seifi, Ali Reza

2014-01-01

Highlights: • A new approach to the problem of optimal reactive power control variables planning is proposed. • The energy loss minimization problem has been formulated by modeling the load of system as a Load Duration Curve. • To solving the energy loss problem, the classic methods and the evolutionary methods are used. • A new proposed fuzzy teaching–learning based algorithm is applied to energy loss problem. • Simulations are done to show the effectiveness and superiority of the proposed algorithm compared with other methods. - Abstract: This paper offers a new approach to the problem of optimal reactive power control variables planning (ORPVCP). The basic idea is division of Load Duration Curve (LDC) into several time intervals with constant active power demand in each interval and then solving the energy loss minimization (ELM) problem to obtain an optimal initial set of control variables of the system so that is valid for all time intervals and can be used as an initial operating condition of the system. In this paper, the ELM problem has been solved by the linear programming (LP) and fuzzy linear programming (Fuzzy-LP) and evolutionary algorithms i.e. MHBMO and TLBO and the results are compared with the proposed Fuzzy-TLBO method. In the proposed method both objective function and constraints are evaluated by membership functions. The inequality constraints are embedded into the fitness function by the membership function of the fuzzy decision and the problem is modeled by fuzzy set theory. The proposed Fuzzy-TLBO method is performed on the IEEE 30 bus test system by considering two different LDC; and it is shown that using this method has further minimized objective function than original TLBO and other optimization techniques and confirms its potential to solve the ORPCVP problem with considering ELM as the objective function

Radial distribution of power starting from the reactivity using nodal schemes of second and third order

International Nuclear Information System (INIS)

Delfin L, A.; Alonso V, G.; Valle G, E. del

2003-01-01

In this work two nodal schemes of finite element are presented, one of second and the other of third order of accurate that allow to determine the radial distribution of power starting from the corresponding reactivities.The schemes here developed were obtained taking as starting point the equation developed by Driscoll et al, the one which is based on the diffusion approach of 1-1/2 energy groups. This equation relates the power fraction of an assemble with their reactivity and with the power fractions and reactivities of the assemblies that its surround it. Driscoll and collaborators they solve in form approximate such equation supposing that the reactivity of each assemble it is but a lineal function of the burnt one of the fuel. The spatial approach carries out it with the classic technique of finite differences centered in mesh. Nevertheless that the algebraic system to which its arrive it can be solved without more considerations introduce some additional suppositions and adjustment parameters that it allows them to predict results comparable to those contributed by three dimensions analysis and this way to reduce the one obtained error when its compare their results with those of a production code like CASMO. Also in the two schemes that here are presented the same approaches of Driscoll were used being obtained errors of the one 10% and of 5% for the second schemes and third order respectively for a test case that it was built starting from data of the Cycle 1 of the Unit 1 of the Laguna Verde Nucleo electric plant. These errors its were obtained when comparing with a computer program based on the matrix response method. It is sought to have this way a quick and efficient tool for the multicycle analysis in the fuel management. However, this model presents problems in the appropriate prediction of the average burnt of the nucleus and of the burnt one by lot. (Author)

Optimizing Energy Savings from Direct-DC in U.S. Residential Buildings

Energy Technology Data Exchange (ETDEWEB)

Garbesi, Karina; Vossos, Vagelis; Sanstad, Alan; Burch, Gabriel

2011-10-13

An increasing number of energy efficient appliances operate on direct current (DC) internally, offering the potential to use DC from renewable energy systems directly and avoiding the losses inherent in converting power to alternating current (AC) and back. This paper investigates that potential for net-metered residences with on-site photovoltaics (PV) by modeling the net power draw of the ‘direct-DC house’ with respect to today’s typical configuration, assuming identical DC-internal loads. Power draws were modeled for houses in 14 U.S. cities, using hourly, simulated PV-system output and residential loads. The latter were adjusted to reflect a 33% load reduction, representative of the most efficient DC-internal technology, based on an analysis of 32 electricity end-uses. The model tested the effect of climate, electric vehicle (EV) loads, electricity storage, and load shifting on electricity savings; a sensitivity analysis was conducted to determine how future changes in the efficiencies of power system components might affect savings potential. Based on this work, we estimate that net-metered PV residences could save 5% of their total electricity load for houses without storage and 14% for houses with storage. Based on residential PV penetration projections for year 2035 obtained from the National Energy Modeling System (2.7% for the reference case and 11.2% for the extended policy case), direct-DC could save the nation 10 trillion Btu (without storage) or 40 trillion Btu (with storage). Shifting the cooling load by two hours earlier in the day (pre-cooling) has negligible benefits for energy savings. Direct-DC provides no energy savings benefits for EV charging, to the extent that charging occurs at night. However, if charging occurred during the day, for example with employees charging while at work, the benefits would be large. Direct-DC energy savings are sensitive to power system and appliance conversion efficiencies but are not significantly

Way to save nuclear power

International Nuclear Information System (INIS)

Brightsen, R.A.

1979-01-01

In the opinion of many citizens, including the majority of those who oppose it, nuclear power will never recover from the 1979 accident at Three Mile Island. But some of nuclear power's supporters hope that the accident will shatter past smugness and spur constructive self-criticism on the part of the companies that build reactors, the utilities that buy them, and the Federal regulators who oversee their operation--and that it will usher in an era of truly safe atomic electricity. The article reviews deficiencies of the existing nuclear regulation - industry framework, and what must be done

Nash equilibrium strategies of generating companies (Gencos) in the simultaneous operation of active and reactive power market, with considering voltage stability margin

International Nuclear Information System (INIS)

Soleymani, S.

2013-01-01

Highlights: ► We model the behavior of Gencos in the active and reactive power markets. ► Genco’s strategy is modeled as a bi-level optimization problem. ► The ISO’s market clearing model is modified with applying generator APFs. ► Good forecast of Genco’s information will increase the accuracy of proposed method. ► Obtained profit of Gencos depend on their bidding strategy. - Abstract: As Gencos are responsible for providing active and reactive power generation, they should devise good bidding strategies for energy and reactive power market. The paper describes a method for analyzing the competition among transmission-constrained Gencos with incomplete information. The proposed methodology employs the Supply Function Equilibrium (SFE) for modeling a Genco’s bidding strategy in energy market and uses Expected Payment Function (EPF) to construct a bidding framework in the reactive power market. The problem of finding the optimum strategy of Gencos is modeled as a bi-level optimization problem, where the upper sub-problem represents individual Genco’s payoff and the lower sub-problem solves the ISO’s market clearing problem. The ISO’s market clearing model is modified with applying generator Active Participation Factors to improve the voltage stability margin. The IEEE 39 bus test system is used to verify the effectiveness of the proposed method.

Natural gas decompression energy recovery: Energy savings potential in Italy

International Nuclear Information System (INIS)

Piatti, A.; Piemonte, C.; Rampini, E.; Vatrano, F.; Techint SpA, Milan; ENEA, Rome

1992-01-01

This paper surveyed the natural gas distribution systems employed in the Italian civil, industrial and thermoelectric sectors to identify those installations which can make use of gas decompression energy recovery systems (consisting of turbo-expanders or alternative expanders) to economically generate electric power. Estimates were then made of the total amount of potential energy savings. The study considered as eligible for energy savings interventions only those plants with a greater than 5,000 standard cubic meter per hour plant capacity. It was evaluated that, with suitable decompression equipment installed at 50 key installations (33 civil, 15 industrial), about 200 GWh of power could be produced annually, representing potential savings of about 22,000 petroleum equivalent tonnes of energy. A comparative analysis was done on three investment alternatives involving inputs of varying amounts of Government financial assistance

Possibilities of using thermal mass in buildings to save energy, cut power consumption peaks and increase the thermal comfort

OpenAIRE

Karlsson, Jonathan

2012-01-01

The aim of this project was to generate knowledge to enable us to take advantage of heat storage in heavy building structures with regard to as energy savings, better thermal indoor climate, and reduced peak powers. This could include buildings that can function without energy input during cold periods, buildings that give a robust indoor climate without installed cooling, and buildings with good thermal comfort also in case of higher outdoor temperatures resulting from global warming. To rea...

Can global warming save nuclear power?

International Nuclear Information System (INIS)

Pearce, D.

1994-01-01

Nuclear powered electricity generation in the United Kingdom has an uncertain future. The relative costs of generating electricity by nuclear fission compared to other means and the need for a desirable mixture or ''portfolio'' of energy sources in the electricity industry are identified as the key to this uncertainty. The author argues that Government commitments to reducing Carbon Monoxide (CO) emissions, and hence global warming, may strengthen arguments in favour of a firm commitment to nuclear power, as even modern fossil-fuelled power plants emit nearly 90 times as much CO as nuclear plants. (UK)

Calculation methods of reactivity using derivatives of nuclear power and Filter fir; Metodos para o calculo da reatividade usando derivadas da potencia nuclear e o filtro FIR

Energy Technology Data Exchange (ETDEWEB)

Diaz, Daniel Suescun

2007-07-01

This work presents two new methods for the solution of the inverse point kinetics equation. The first method is based on the integration by parts of the integral of the inverse point kinetics equation, which results in a power series in terms of the nuclear power in time dependence. Applying some conditions to the nuclear power, the reactivity is represented as first and second derivatives of this nuclear power. This new calculation method for reactivity has special characteristics, amongst which the possibility of using different sampling periods, and the possibility of restarting the calculation, after its interruption associated it with a possible equipment malfunction, allowing the calculation of reactivity in a non-continuous way. Apart from this reactivity can be obtained with or without dependency on the nuclear power memory. The second method is based on the Laplace transform of the point kinetics equations, resulting in an expression equivalent to the inverse kinetics equation as a function of the power history. The reactivity can be written in terms of the summation of convolution with response to impulse, characteristic of a linear system. For its digital form the Z-transform is used, which is the discrete version of the Laplace transform. In this method it can be pointed out that the linear part is equivalent to a filter named Finite Impulse Response (Fir). The Fir filter will always be, stable and non-varying in time, and, apart from this, it can be implemented in the non-recursive way. This type of implementation does not require feedback, allowing the calculation of reactivity in a continuous way. The proposed methods were validated using signals with random noise and showing the relationship between the reactivity difference and the degree of the random noise. (author)

Net fossil energy savings for alternative mixes in various electric supply systems

International Nuclear Information System (INIS)

Essam, P.; Stocks, K.J.

1978-11-01

The actual and projected electric power station building programs of several countries and regions have been examined to determine what effect the introduction of nuclear power has on fossil fuel usage by the electricity system. It was found that (1) nuclear power leads directly to savings in fossil fuel usage, a larger nuclear component leading to larger savings; (2) individual nuclear stations rapidly wipe out the energy 'debt' incurred during building; and (3) the relatively short periods of consolidation in the early stages of a nation's building program usually prevent the nuclear component from going into energy 'debt'. Assessments of the energy requirements to build and run various types of power station have been made from the available literature

Saving energy resources during heat treatment - the most important problem of the branch

Energy Technology Data Exchange (ETDEWEB)

Zadernovskiy, V V; Firger, I V

1980-01-01

Natural gas fired thermal furnaces expend significantly less fuel than electric furnaces with an equal quality of metal heating. An important reserve in power reserve economy is the use of the forging heat in an article for heat treatment (TOB), where besides the power resources, metal is also saved as a result of the reduction in the volume of heating means and production spaces. From the experience in the progressive enterprises of the branch, in a number of cases it is possible to combine heating for plastic deformation with heating for primary or secondary heat treatment. Other measures are examined which save power resources in heat treatment: the use of thermal furnaces for aerodynamic heating, the use of local heat treatment, the reduction in the duration of the heat treatment processes, savings in the power carriers during heat treatment in furnaces with a roll out hearth. Fibrous refractory materials are being used more and more as fettling materials in the construction of thermal furnaces.

Preliminary study on the reactivation of the WERAP small hydro power station in Bubikon

International Nuclear Information System (INIS)

Bretscher, A.; Gutzwiller, S.

2003-01-01

This study on the revitalisation of a small hydro power station belonging to old spinning mill in Bubikon, Switzerland, proposes ideas for the reactivation of an old hydropower installation that once helped power a spinning mill. Details are given on the history of the mill and the hydrological conditions to be expected at the site. Three variants are proposed for the refurbishment, including the revision of the power station's existing 44 kW Francis turbine dating from 1908, the addition of further, similar Francis turbine or its replacement with a new 61 kW Francis turbine. The costs and amortisation of the refurbishment variants are examined, the revenues that can be expected from its operation and other financial factors are discussed. Further, environmental and legal aspects of the project are examined and suggestions are made for the next steps to be taken towards the realisation of this small hydropower plant. An annex provides photographs of the location and the power station's equipment

C. h. p. saves fuel in Sweden

Energy Technology Data Exchange (ETDEWEB)

Daugas, C F

1979-04-01

A combined heat and power plant based on a diesel generator to produce 12MW of electricity and 12MW of heat has successfully supplied the town of Skultuna in Sweden during the winter and has saved 3,700t of oil annually.

Household Savings

DEFF Research Database (Denmark)

Browning, Martin; Lusardi, Annamaria

suggested in the informal saving literature can be captured in the standard optimizing model. Particular attention is given to recent work on the precautionary motive and its implications for saving and consumption behavior. We also discuss the "behavioral" or "psychological" approach that eschews the use......In this survey, we review the recent theoretical and empirical literature on household saving and consumption. The discussion is structured around a list of motives for saving and how well the standard theory captures these motives. We show that almost all of the motives for saving that have been...

Defining a standard metric for electricity savings

International Nuclear Information System (INIS)

Koomey, Jonathan; Akbari, Hashem; Blumstein, Carl; Brown, Marilyn; Brown, Richard; Calwell, Chris; Carter, Sheryl; Cavanagh, Ralph; Chang, Audrey; Claridge, David; Craig, Paul; Diamond, Rick; Eto, Joseph H; Fulkerson, William; Gadgil, Ashok; Geller, Howard; Goldemberg, Jose; Goldman, Chuck; Goldstein, David B; Greenberg, Steve

2010-01-01

The growing investment by governments and electric utilities in energy efficiency programs highlights the need for simple tools to help assess and explain the size of the potential resource. One technique that is commonly used in this effort is to characterize electricity savings in terms of avoided power plants, because it is easier for people to visualize a power plant than it is to understand an abstraction such as billions of kilowatt-hours. Unfortunately, there is no standardization around the characteristics of such power plants. In this letter we define parameters for a standard avoided power plant that have physical meaning and intuitive plausibility, for use in back-of-the-envelope calculations. For the prototypical plant this article settles on a 500 MW existing coal plant operating at a 70% capacity factor with 7% T and D losses. Displacing such a plant for one year would save 3 billion kWh/year at the meter and reduce emissions by 3 million metric tons of CO 2 per year. The proposed name for this metric is the Rosenfeld, in keeping with the tradition among scientists of naming units in honor of the person most responsible for the discovery and widespread adoption of the underlying scientific principle in question-Dr Arthur H Rosenfeld.

Defining a standard metric for electricity savings

Energy Technology Data Exchange (ETDEWEB)

Koomey, Jonathan [Lawrence Berkeley National Laboratory and Stanford University, PO Box 20313, Oakland, CA 94620-0313 (United States); Akbari, Hashem; Blumstein, Carl; Brown, Marilyn; Brown, Richard; Calwell, Chris; Carter, Sheryl; Cavanagh, Ralph; Chang, Audrey; Claridge, David; Craig, Paul; Diamond, Rick; Eto, Joseph H; Fulkerson, William; Gadgil, Ashok; Geller, Howard; Goldemberg, Jose; Goldman, Chuck; Goldstein, David B; Greenberg, Steve, E-mail: JGKoomey@stanford.ed

2010-01-15

The growing investment by governments and electric utilities in energy efficiency programs highlights the need for simple tools to help assess and explain the size of the potential resource. One technique that is commonly used in this effort is to characterize electricity savings in terms of avoided power plants, because it is easier for people to visualize a power plant than it is to understand an abstraction such as billions of kilowatt-hours. Unfortunately, there is no standardization around the characteristics of such power plants. In this letter we define parameters for a standard avoided power plant that have physical meaning and intuitive plausibility, for use in back-of-the-envelope calculations. For the prototypical plant this article settles on a 500 MW existing coal plant operating at a 70% capacity factor with 7% T and D losses. Displacing such a plant for one year would save 3 billion kWh/year at the meter and reduce emissions by 3 million metric tons of CO{sub 2} per year. The proposed name for this metric is the Rosenfeld, in keeping with the tradition among scientists of naming units in honor of the person most responsible for the discovery and widespread adoption of the underlying scientific principle in question-Dr Arthur H Rosenfeld.

Defining a Standard Metric for Electricity Savings

Energy Technology Data Exchange (ETDEWEB)

Brown, Marilyn; Akbari, Hashem; Blumstein, Carl; Koomey, Jonathan; Brown, Richard; Calwell, Chris; Carter, Sheryl; Cavanagh, Ralph; Chang, Audrey; Claridge, David; Craig, Paul; Diamond, Rick; Eto, Joseph H.; Fulkerson, William; Gadgil, Ashok; Geller, Howard; Goldemberg, Jose; Goldman, Chuck; Goldstein, David B.; Greenberg, Steve; Hafemeister, David; Harris, Jeff; Harvey, Hal; Heitz, Eric; Hirst, Eric; Hummel, Holmes; Kammen, Dan; Kelly, Henry; Laitner, Skip; Levine, Mark; Lovins, Amory; Masters, Gil; McMahon, James E.; Meier, Alan; Messenger, Michael; Millhone, John; Mills, Evan; Nadel, Steve; Nordman, Bruce; Price, Lynn; Romm, Joe; Ross, Marc; Rufo, Michael; Sathaye, Jayant; Schipper, Lee; Schneider, Stephen H; Sweeney, James L; Verdict, Malcolm; Vorsatz, Diana; Wang, Devra; Weinberg, Carl; Wilk, Richard; Wilson, John; Worrell, Ernst

2009-03-01

The growing investment by governments and electric utilities in energy efficiency programs highlights the need for simple tools to help assess and explain the size of the potential resource. One technique that is commonly used in this effort is to characterize electricity savings in terms of avoided power plants, because it is easier for people to visualize a power plant than it is to understand an abstraction such as billions of kilowatt-hours. Unfortunately, there is no standardization around the characteristics of such power plants. In this letter we define parameters for a standard avoided power plant that have physical meaning and intuitive plausibility, for use in back-of-the-envelope calculations. For the prototypical plant this article settles on a 500 MW existing coal plant operating at a 70percent capacity factor with 7percent T&D losses. Displacing such a plant for one year would save 3 billion kW h per year at the meter and reduce emissions by 3 million metric tons of CO2 per year. The proposed name for this metric is the Rosenfeld, in keeping with the tradition among scientists of naming units in honor of the person most responsible for the discovery and widespread adoption of the underlying scientific principle in question--Dr. Arthur H. Rosenfeld.

A Single-Stage LED Tube Lamp Driver with Power-Factor Corrections and Soft Switching for Energy-Saving Indoor Lighting Applications

Directory of Open Access Journals (Sweden)

Chun-An Cheng

2017-01-01

Full Text Available This paper presents a single-stage alternating current (AC/direct current (DC light-emitting diode (LED tube lamp driver for energy-saving indoor lighting applications; this driver features power-factor corrections and soft switching, and also integrates a dual buck-boost converter with coupled inductors and a half-bridge series resonant converter cascaded with a bridge rectifier into a single-stage power-conversion topology. The features of the presented driver are high efficiency (>91%, satisfying power factor (PF > 0.96, low input-current total-harmonic distortion (THD < 10%, low output voltage ripple factor (<7.5%, low output current ripple factor (<8%, and zero-voltage switching (ZVS obtained on both power switches. Operational principles are described in detail, and experimental results obtained from an 18 W-rated LED tube lamp for T8/T10 fluorescent lamp replacements with input utility-line voltages ranging from 100 V to 120 V have demonstrated the functionality of the presented driver suitable for indoor lighting applications.

Microgrid Reactive and Harmonic Power Sharing Using Enhanced Virtual Impedance

DEFF Research Database (Denmark)

He, Jinwei; Wei Li, Yun; Guerrero, Josep M.

2013-01-01

To address the load sharing problem in islanding microgrids, this paper proposes an improved approach which regulates the distributed generation (DG) unit interfacing virtual impedance at fundamental and selected harmonic frequencies. In contrast to the conventional virtual impedance control where...... only a line current feed-forward term is added to the DG voltage reference, the proposed virtual impedances at fundamental and harmonic frequencies are realized using DG line current and point of common coupling (PCC) voltage feed-forward terms, respectively. With this modification, the mismatched DG...... feeder impedances can be properly compensated, resulting in accurate reactive and harmonic power sharing at the same time. In addition, this paper shows that the microgrid PCC harmonic voltages can be mitigated by reducing the magnitude of DG unit equivalent harmonic impedance. Finally, an improved...

Saving in cycles: how to get people to save more money.

Science.gov (United States)

Tam, Leona; Dholakia, Utpal

2014-02-01

Low personal savings rates are an important social issue in the United States. We propose and test one particular method to get people to save more money that is based on the cyclical time orientation. In contrast to conventional, popular methods that encourage individuals to ignore past mistakes, focus on the future, and set goals to save money, our proposed method frames the savings task in cyclical terms, emphasizing the present. Across the studies, individuals who used our proposed cyclical savings method, compared with individuals who used a linear savings method, provided an average of 74% higher savings estimates and saved an average of 78% more money. We also found that the cyclical savings method was more efficacious because it increased implementation planning and lowered future optimism regarding saving money.

A CLS-based survivable and energy-saving WDM-PON architecture

Science.gov (United States)

Zhu, Min; Zhong, Wen-De; Zhang, Zhenrong; Luan, Feng

2013-11-01

We propose and demonstrate an improved survivable and energy-saving WDM-PON with colorless ONUs. It incorporates both energy-saving and self-healing operations. A simple effective energy-saving scheme is proposed by including an energy-saving control unit in the OLT and a control unit at each ONU. The energy-saving scheme realizes both dozing and sleep (offline) modes, which greatly improves the energy-saving efficiency for WDM-PONs. An intelligent protection switching scheme is designed in the OLT, which can distinguish if an ONU is in dozing/sleep (offline) state or a fiber is faulty. Moreover, by monitoring the optical power of each channel on both working and protection paths, the OLT can know the connection status of every fiber path, thus facilitating an effective protection switching and a faster failure recovery. The improved WDM-PON architecture not only significantly reduces energy consumption, but also performs self-healing operation in practical operation scenarios. The scheme feasibility is experimentally verified with 10 Gbit/s downstream and 1.25 Gbit/s upstream transmissions. We also examine the energy-saving efficiency of our proposed energy-saving scheme by simulation, which reveals that energy saving mainly arises from the dozing mode, not from the sleep mode when the ONU is in the online state.

Development of Improved Burnable Poisons for Commercial Nuclear Power Reactors

Energy Technology Data Exchange (ETDEWEB)

Renier, J.A.

2002-04-17

water reactor fuel core was chosen for the study, and state-of-the-art neutronic reactor core computer codes were used for analysis. Power distribution, fuel burnup, reactivity due to burnable poisons and other fission products, spectrum shift, core reactivity, moderator void coefficients, as well as other parameters were calculated as a function of time and fuel burnup. The results not only showed advantages of separation of burnable poison isotopes but revealed benefits to be achieved by careful selection of the configuration of even naturally occurring elements used as burnable poisons. The savings in terms of additional days of operation is shown in Figure 1, where the savings is plotted for each of six favorable isotopes in the four configurations. The benefit of isotope separation is most dramatic for dysprosium, but even the time savings in the case of gadolinium is several days. For a modern nuclear plant, one day's worth of electricity is worth about one million dollars, so the resulting savings of only a few days is considerable. It is also apparent that the amount of savings depends upon the configuration of the burnable poison.

Stakeholders’ influence on the adoption of energy-saving technologies in Italian homes

International Nuclear Information System (INIS)

Berardi, Umberto

2013-01-01

The instability and fragmentation of the temporary aggregations of many stakeholders in construction processes are barriers to adopting new technologies. This paper investigates the influence of different stakeholders on the adoption of mature energy-saving technologies in new residential buildings. Recent literature about the influence of different stakeholders on construction processes is reviewed focusing in their interest for energy saving technologies. To gain an insight into the specific roles played by stakeholders (general contractors, construction firms, architects, users and public governments) in different projects, a case study methodology was used. The influence on the adoption of energy-saving technologies of stakeholders was assessed through semi-structured interviews. These interviews focused on the interest and power for the adoption of several energy-saving technologies. Having recognized that the interest in adoption is often expressed late in the construction processes, the time of introduction of this interest was assessed. This paper provides an empirical insight into significant barriers for the adoption of energy saving technologies which are the low influence of highly motivated stakeholders on the decision of adoption, and the delay at which the interest in energy-saving technologies emerges. Finally, policies to overcome these barriers are suggested. - Highlights: • Why energy saving technologies are rarely adopted in buildings? • Diffusion is slowed by the late participation of stakeholders with great interest for energy technologies. • The influence of construction stakeholders for the adoption of energy saving technologies is measured in Italian case studies. • More integrated relationships among stakeholders are required to help the adoption of energy saving technologies. • Process re-organizations and policies which increase final users’ power are needed

How to tackle energy saving and load leveling. Energy saving towards 2000 and measures for the coming winter (energy-saving activities by California`s SCE, demand side management activities); Sho energy fuka heijunka ni do torikumuka. Seireki 2000 nen ni muketa sho energy to konto no shoene taisaku, Kashu SCE no sho energy (DSM katsudo wo saguru)

Energy Technology Data Exchange (ETDEWEB)

Nasu, S. [The Energy Conservation Center Japan, Tokyo (Japan)

1997-02-01

Tokyo Electric Power has realized a peak shift of 5% for the maximum power demand by various measures to cope with increasing power demand and differential rate by time zone, including expansion of the differential rate system and heat-storage systems. Some of more notable recent techniques are eco-ice and eco-vendor systems, the former storing ice in the heat-storage tanks and the latter strongly cooling vending machines during nighttime. The NAS battery system is being developed as the new technique for load leveling. The energy-related advisory organ for Minister of International Trade and Industry asks each industrial unit to save at least 1% of power on the annual average as the energy-saving measure towards 2000. The energy-saving measures promoted by the government for the coming winter are controlled release of wastes, efficient use of power, setting room temperature at 19{degree}C or lower and voluntarily refrain from commuting by cars. The US power industry is abandoning the concept of DSM in the midst of deregulation and increased competition, and cutting budgets for new energy development. California`s SCE is promoting energy-saving through expanded use of high-efficiency motors, accurate grasp of customers` needs and publicity activities through internet systems. 4 figs., 1 tab.

Determination of the excess of reactivity in a nuclear configuration and its influence on the power level

International Nuclear Information System (INIS)

Zuniga, Agustin; Tapia, Jose

2014-01-01

This work presents experimental results which show that the critical position of a given nuclear configuration changes with the reactor power (expressed by the current measurement). Thus, if the current is 0.6 x 10 -11 A (1 W), then the critical position is, BC1 = 0.0 % while 0.6 x 10 -9 A (100 W), BC1= 46.5 %. The difference is apparent because under a current of 10 -10 A, the reactivity is not significant. Therefore, it is recommended that for reactors like the RP-10 with a lot of neutrons at the 'background' level, the excess reactivity must be measured in current as 0.6 x 10 -9 A (100 W) not less. Finally, the excess of reactivity for the N o 42 configuration was determined, which was 3032 pcm with uncertainty less than 1 %. (authors).

Energy/bandwidth-Saving Cooperative Spectrum Sensing for Two-hopWRAN

Directory of Open Access Journals (Sweden)

Ming-Tuo Zhou

2014-07-01

Full Text Available A two-hop wireless regional area network (WRAN providing monitoring services operating in Television White Space (TVWS, i.e., IEEE P802.22b, may employ a great number of subscriber customer-premises equipments (S-CPEs possibly without mains power supply, leading to requirement of cost-effective and power-saving design. This paper proposes a framework of cooperative spectrum sensing (CSS and an energy/bandwidth saving CSS scheme to P802.22b. In each round of sensing, S-CPEs with SNRs lower than a predefined threshold are excluded from reporting sensing results. Numerical results show that the fused missed-detection probability and false alarmprobability could remainmeeting sensing requirements, and the overall fused error probability changes very little. With 10 S-CPEs, it is possible to save more than 40% of the energy/bandwidth on a Rayleigh channel. The principle proposed can apply to other advanced sensing technologies capable of detecting primary signals with low average SNR.

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...

National supply of reactivity control rods for Embalse nuclear power plant (CNE)

International Nuclear Information System (INIS)

Biondo, C.D.; Carloni, J.G.; Aba, J.A.

1987-01-01

The manufacture and supply on industrial scale of reactivity control rods for CNE (Embalse nuclear power plant) were developed by the National Atomic Energy Commission (CNEA) together with the private industry, as part of a program aimed to the substitution of imported supplies used in the operation of power plants by materials manufactured in Argentina. So far, the control rods were imported from Canada. In this work, the different development stages performed by CNEA and CONUAR S.A. are described, leading to the supply of a set of 21 cobalt rods to be included in a reactor of CNE in order to qualify this component. Among the main activities performed, the following stand out: specifications development, particularly those concerning to cobalt cores, evaluation of design documentation and elaboration of bidding conditions and a plan of manufacture and control. According to the results obtained during the service and the post-irradiation measurements, the design will be reviewed in order to undertake new manufacturing plans. (Author)

Promoting energy-saving and environmentally friendly generation dispatching model in China: Phase development and case studies

International Nuclear Information System (INIS)

Ding, Yi; Yang, Hongliang

2013-01-01

Energy saving and environmental protection are important conditions for the sustainable development of Chinese economy. However current widely used generation scheduling model based on predefined production quota and tariff results in heavy energy consumption and severe environment pollution. From 2007, as concerns over energy shortage and environmental pollution, the Chinese authorities introduced the implementation of energy-saving generation dispatching model, which is an important approach to facilitating energy-saving and reduction of pollutant emission. The objective of implementing energy-saving generation dispatching model is to prioritize the use of renewable energy resources and new power plants with high efficiency without compromising power system security and reliability. This paper analyzes the necessity and feasibility of implementing energy-efficient and environmentally friendly generation scheduling models in China. The institutional and technical barriers impeding the implementation of energy-saving generation dispatching model are identified. The development of advanced energy-saving generation scheduling models towards competitive market models and phased planning programs are emphasized in this paper. The effectiveness and experience of provinces piloted energy-saving generation dispatching projects are also discussed. - Highlights: ► Introducing problems of current power generation scheduling model in China. ► Discussing necessity of implementing ESGD model and corresponding barriers. ► Proposing phased planning programs for developing ESGD models. ► Discussing the effectiveness and experience of provinces piloted ESGD projects

Electricity consumption and electricity saving in the Swedish households

Energy Technology Data Exchange (ETDEWEB)

Bernstroem, B M; Eklund, Y; Sjoeberg, L

1997-03-01

The objective of the present study is to determine which factors influence electricity consumption behavior of Swedish households, the level of knowledge about electricity use and the willingness to pay for the use of electricity. In Sweden, as in many other developed countries, the need for electric power is constantly increasing. The major reason for this increase in electricity consumption is the lifestyle of a modern society. A feature in the nuclear power discussion is that the government in Sweden is having a hard time to establish how to phase-out all nuclear power plants by 2010. An additional major change in Swedish energy policy is the deregulation of the electricity market, which started in the beginning of 1996. There is an increased demand for strategies to save electricity among households. The results of this study stress the difficulties in reducing electricity consumption and to develop new electricity saving strategies in Sweden 125 refs, 6 figs, 21 tabs

Measurement of the CNA I's (Atucha I nuclear power plant) control rods reactivity during its commissioning on January 8th, 1990

International Nuclear Information System (INIS)

Waldman, R.M.; Gomez, A.

1990-01-01

Measurements were made on integral and differential calibration of rod 16, fuel racks RG and R3 and extinction reactivity during Atucha I nuclear power plant's commissioning on January 8th., 1990. These were the first physical measurements performed after the first critical nuclear power plant's commissioning. (Author) [es

Active and reactive power support of MV distribution systems using battery energy storage

DEFF Research Database (Denmark)

Wang, Jiawei; Hashemi Toghroljerdi, Seyedmostafa; You, Shi

2017-01-01

shaving and voltage support service from the perspective of Distribution System Operators (DSOs). An active power support algorithm is implemented and the effects of various load profiles as well as different Photovoltaic (PV) penetration scenarios on the operation of BESS and the optimal BESS converter......Adoption of Battery Energy Storage Systems (BESSs) for provision of grid services is increasing. This paper investigates the applications of BESS for the grid upgrade deferral and voltage support of Medium Voltage (MV) distribution systems. A BESS is modelled in Matlab/Simulink to perform peak load...... size for peak load shaving are investigated. The BESS annual lifetime degradation is also estimated using a rainflow counting algorithm. A reactive power support algorithm embedded with Q-U droop control is proposed in order to reduce the voltage drop in a part of 10 kV distribution network of Nordhavn...

Insertion material for controlling reactivity

International Nuclear Information System (INIS)

Baba, Iwao.

1994-01-01

Moderators and a group of suspended materials having substantially the same density as the moderator are sealed in a hollow rod vertically inserted to a fuel assembly. Specifically, the group of suspended materials is adapted to have a density changing stepwise from density of the moderator at the exit temperature of the reactor core to that at the inlet temperature of the reactor core. Reactivity is selectively controlled for a portion of high power and a portion of high reactivity by utilizing the density of the moderator and the distribution of the density. That is, if the power distribution is flat, the density of the moderators changes at a constant rate over the vertical direction of the reactor core and the suspended materials stay at a portion of the same density, to form a uniform distribution. Further, upon reactor shutdown, since the liquid temperature of the moderators is lowered and the density is increased, all of beads are collected at the upper portion to remove water at the upper portion of the reactor core of low burnup degree thereby selectively controlling the reactivity at a portion of high power and a portion of high reactivity. (N.H.)

Example for electrical energy savings with the pump adjustable electric drive

International Nuclear Information System (INIS)

Mirchevski, Slobodan; Andonov, Zdravko; Saracevic, Fahrudin; Micevski, Darko; Buchkoski, Aleksandar

2004-01-01

Most used method of flow regulation is by throttling the pipeline. Development of power electronic gives opportunity for induction motor pump drives speed control. The common ways of pump flow control are throttling, reducing the working circle, usage of fore circle shovels rotating, by pass and pump speed control Only pump speed control is the most suitable for the energy possibilities. Intensive development of power electronic gives. opportunity to create devices - power converters, which can change the speed of induction motor. For that improvement the energy savings the measurements of power consumption with throttling and speed control have been made. Also, the MATLAB-SIMULINK model of the measured system has been made. The economic effects of saving energy using adjustable speed drives are analyzed for the measured values. The analysis shows that the money payback period of speed controller investment is short compared with the drive lifetime (20 years). (Author)

Assessment of women savings and credit cooperative services in ...

African Journals Online (AJOL)

Assessment of women savings and credit cooperative services in Zuway Dugda District, south east Ethiopia. ... Journal of Business and Administrative Studies ... and to the improvement of decision making power of members at family level.

Reactivity costs in MARIA reactor

International Nuclear Information System (INIS)

Marcinkowska, Zuzanna E.; Pytel, Krzysztof M.; Frydrysiak, Andrzej

2017-01-01

Highlights: • The methodology for calculating consumed fuel cost of excess reactivity is proposed. • Correlation between time integral of the core excess reactivity and released energy. • Reactivity price gives number of fuel elements required for given excess reactivity. - Abstract: For the reactor operation at high power level and carrying out experiments and irradiations the major cost of reactor operation is the expense of nuclear fuel. In this paper the methodology for calculating consumed fuel cost-relatedness of excess reactivity is proposed. Reactivity costs have been determined on the basis of operating data. A number of examples of calculating the reactivity costs for processes such as: strong absorbing material irradiation, molybdenium-99 production, beryllium matrix poisoning and increased moderator temperature illustrates proposed method.

Energy-saving approaches to solid state street lighting

Science.gov (United States)

Vitta, Pranciškus; Stanikūnas, Rytis; Tuzikas, Arūnas; Reklaitis, Ignas; Stonkus, Andrius; Petrulis, Andrius; Vaitkevičius, Henrikas; Žukauskas, Artūras

2011-10-01

We consider the energy-saving potential of solid-state street lighting due to improved visual performance, weather sensitive luminance control and tracking of pedestrians and vehicles. A psychophysical experiment on the measurement of reaction time with a decision making task was performed under mesopic levels of illumination provided by a highpressure sodium (HPS) lamp and different solid-state light sources, such as daylight and warm-white phosphor converted light-emitting diodes (LEDs) and red-green-blue LED clusters. The results of the experiment imply that photopic luminances of road surface provided by solid-state light sources with an optimized spectral power distribution might be up to twice as low as those provided by the HPS lamp. Dynamical correction of road luminance against road surface conditions typical of Lithuanian climate was estimated to save about 20% of energy in comparison with constant-level illumination. The estimated energy savings due to the tracking of pedestrians and vehicles amount at least 25% with the cumulative effect of intelligent control of at least 40%. A solid-state street lighting system with intelligent control was demonstrated using a 300 m long test ground consisting of 10 solid-state street luminaires, a meteorological station and microwave motion sensor network operated via power line communication.

Save production: a bottom-up energy model for Dutch industry and agriculture

International Nuclear Information System (INIS)

Daniels, B.W.; Dril, A.W.N. van

2007-01-01

A new version of the model Save production simulates the development of energy use in the Dutch industry and agriculture, including combined heat and power generation. The model disaggregates national energy consumption into fuel types, industrial sectors, energy functions and energy technologies. Simulation is based on microeconomic investment behavior. Examples of model application show results on the penetration of combined heat and power in relation to policy instruments such as CO 2 prices, electricity price support and investment subsidies. Policies that discriminate on CO 2 emissions result in a slightly more efficient heat and power generation. Tailored to the Dutch situation, Save production is well equipped to generate outlooks for the Dutch industrial and agricultural energy use, and for analyzing the role of policies in detail. Its main strength lies in the middle term simulation of decision-making on energy saving technologies and analysis of policy effects. Specific precautions are required when the model is used for analysis on the longer-term, for simulating extreme policies or for the analysis of extremely fluctuating energy prices. (author)

Reactivity balance for a soluble boron-free small modular reactor

Directory of Open Access Journals (Sweden)

Lezani van der Merwe

2018-06-01

Full Text Available Elimination of soluble boron from reactor design eliminates boron-induced reactivity accidents and leads to a more negative moderator temperature coefficient. However, a large negative moderator temperature coefficient can lead to large reactivity feedback that could allow the reactor to return to power when it cools down from hot full power to cold zero power. In soluble boron-free small modular reactor (SMR design, only control rods are available to control such rapid core transient.The purpose of this study is to investigate whether an SMR would have enough control rod worth to compensate for large reactivity feedback. The investigation begins with classification of reactivity and completes an analysis of the reactivity balance in each reactor state for the SMR model.The control rod worth requirement obtained from the reactivity balance is a minimum control rod worth to maintain the reactor critical during the whole cycle. The minimum available rod worth must be larger than the control rod worth requirement to manipulate the reactor safely in each reactor state. It is found that the SMR does have enough control rod worth available during rapid transient to maintain the SMR at subcritical below k-effectives of 0.99 for both hot zero power and cold zero power. Keywords: Control Rod Worth, Reactivity Balance, Reactivity Feedback, Small Modular Reactor, Soluble Boron Free

Inherent Safety Feature of Hybrid Low Power Research Reactor during Reactivity Induced Accident

Energy Technology Data Exchange (ETDEWEB)

Kim, DongHyun; Yum, Soo Been; Hong, Sung Teak; Lim, In-Cheol [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2016-10-15

Hybrid low power research reactor(H-LPRR) is the new design concept of low power research reactor for critical facility as well as education and training. In the case of typical low power research reactor, the purposes of utilization are the experiments for education of nuclear engineering students, Neutron Activation Analysis(NAA) and radio-isotope production for research purpose. H-LPRR is a light-water cooled and moderated research reactor that uses rod-type LEU UO{sub 2} fuels same as those for commercial power plants. The maximum core thermal power is 70kW and, the core is placed in the bottom of open pool. There are 1 control rod and 2 shutdown rods in the core. It is designed to cool the core by natural convection, retain negative feedback coefficient for entire fuel periods and operate for 20 years without refueling. Inherent safety in H-LPRR is achieved by passive design features such as negative temperature feedback coefficient and core cooling by natural convection during normal and emergency conditions. The purpose of this study is to find out that the inherent safety characteristics of H-LPRR is able to control the power and protect the reactor from the RIA(Reactivity induced accident). RIA analysis was performed to investigate the inherent safety feature of H-LPRR. As a result, it was found that the reactor controls its power without fuel damage in the event and that the reactor remains safe states inherently. Therefore, it is believed that high degree of safety inheres in H-LPRR.

Development of a standard for calculation and measurement of the moderator temperature coefficient of reactivity in water-moderated power reactors

International Nuclear Information System (INIS)

Mosteller, R.D.; Hall, R.A.; Lancaster, D.B.; Young, E.H.; Gavin, P.H.; Robertson, S.T.

1998-01-01

The contents of ANS 19.11, the standard for ''Calculation and Measurement of the Moderator Temperature Coefficient of Reactivity in Water-Moderated Power Reactors,'' are described. The standard addresses the calculation of the moderator temperature coefficient (MTC) both at standby conditions and at power. In addition, it describes several methods for the measurement of the at-power MTC and assesses their relative advantages and disadvantages. Finally, it specifies a minimum set of documentation requirements for compliance with the standard

Loss of Excitation Detection in Doubly Fed Induction Generator by Voltage and Reactive Power Rate

Directory of Open Access Journals (Sweden)

M. J. Abbasi

2016-12-01

Full Text Available The doubly fed induction generator (DFIG is one of the most popular technologies used in wind power systems. With the growing use of DFIGs and increasing power system dependence on them in recent years, protecting of these generators against internal faults is more considered. Loss of excitation (LOE event is among the most frequent failures in electric generators. However, LOE detection studies heretofore were usually confined to synchronous generators. Common LOE detection methods are based on impedance trajectory which makes the system slow and also prone to interpret a stable power swing (SPS as a LOE fault. This paper suggests a new method to detect the LOE based on the measured variables from the DFIG terminal. In this combined method for LOE detection, the rate of change of both the terminal voltage and the output reactive power are utilized and for SPS detection, the fast Fourier transform (FFT analysis of the output instantaneous active power has been used. The performance of the proposed method was evaluated using Matlab/Simulink interface for various power capacities and operating conditions. The results proved the method's quickness, simplicity and security.

Local Dynamic Reactive Power for Correction of System Voltage Problems

Energy Technology Data Exchange (ETDEWEB)

Kueck, John D [ORNL; Rizy, D Tom [ORNL; Li, Fangxing [ORNL; Xu, Yan [ORNL; Li, Huijuan [University of Tennessee, Knoxville (UTK); Adhikari, Sarina [ORNL; Irminger, Philip [ORNL

2008-12-01

Distribution systems are experiencing outages due to a phenomenon known as local voltage collapse. Local voltage collapse is occurring in part because modern air conditioner compressor motors are much more susceptible to stalling during a voltage dip than older motors. These motors can stall in less than 3 cycles (.05s) when a fault, such as on the sub-transmission system, causes voltage to sag to 70 to 60%. The reasons for this susceptibility are discussed in the report. During the local voltage collapse, voltages are depressed for a period of perhaps one or two minutes. There is a concern that these local events are interacting together over larger areas and may present a challenge to system reliability. An effective method of preventing local voltage collapse is the use of voltage regulation from Distributed Energy Resources (DER) that can supply or absorb reactive power. DER, when properly controlled, can provide a rapid correction to voltage dips and prevent motor stall. This report discusses the phenomenon and causes of local voltage collapse as well as the control methodology we have developed to counter voltage sag. The problem is growing because of the use of low inertia, high efficiency air conditioner (A/C) compressor motors and because the use of electric A/C is growing in use and becoming a larger percentage of system load. A method for local dynamic voltage regulation is discussed which uses reactive power injection or absorption from local DER. This method is independent, rapid, and will not interfere with conventional utility system voltage control. The results of simulations of this method are provided. The method has also been tested at the ORNL s Distributed Energy Communications and Control (DECC) Laboratory using our research inverter and synchronous condenser. These systems at the DECC Lab are interconnected to an actual distribution system, the ORNL distribution system, which is fed from TVA s 161kV sub-transmission backbone. The test results

Parametric identification of an asynchronous machine by the reactive power method; Identificacao parametrica de uma maquina assincrona pelo metodo da potencia reativa

Energy Technology Data Exchange (ETDEWEB)

Silva, Alexandre Alves Sampaio e

1996-07-01

The obtention of the electrical and mechanical parameters of a squirrel-cage induction motor is investigated. Two methods of identification are studied: the reactive power method, used to determine the electrical parameters and an acceleration method on a startup test used to to find the mechanical ones. The method of reactive power is developed by analysing the machine steady state operation. In this analysis, a relationship between the electrical parameters and the reactive power is obtained. A minimization algorithm is used to determine the parameters based on this relationship. The acceleration method uses an acquisition of the transient variables, which is used in a recursive least square method furnishing the mechanical parameters. Both of methods are implemented on a special hardware and software system, consisting of sensors and A/D boards that make a digital acquisition of voltage, current and speed values. The validation procedures for the method and parameters are based on comparing between the real and simulated evaluation of the dynamical behavior of the motor in a startup test. The skin-effect influence over some of the motor parameters was also discussed. (author)

Integrated reactive self-assessment for programmatic learning

International Nuclear Information System (INIS)

Corcoran, W.R.

1996-01-01

This paper presents a generalized method for using reactive self-assessment. The application is to programmatic learning involving the integration of reactive self-assessment results over a period of time. This paper also presents some of the results of one application of the process. Self-assessment, in general, is the assessment conducted or sponsored by an individual or organization of its own activities for the purpose of detecting improvement opportunities, either of the corrective or the enhancement types. Reactive self-assessment is a self-assessment activity conducted in reaction to a shortfall event. An integrative reactive self-assessment is a self-assessment that integrates a set of reactive self-assessment results. Programmatic learning is increasing the knowledge base in a program area. Self-assessment, in general, and reactive self-assessment, in particular, are required by federal quality requirements. One such program area is nuclear power plant testing, which is also required by federal quality requirements. Any program area could have been selected, but this one was selected because it was involved in the Chernobyl accident, the most consequential nuclear power accident up until the time of this writing. Other consequential accidents involving nuclear power plant testing were the Browns Ferry fire and the Salem overspeed event. (The author, of course, does not conduct nuclear power plant testing but is doing a self-assessment as if he were acting for an organization that did testing.)

Promoting energy-saving and environmentally friendly generation dispatching model in China: Phase development and case studies

DEFF Research Database (Denmark)

Ding, Yi; Yang, Hongliang

2013-01-01

Energy saving and environmental protection are important conditions for the sustainable development of Chinese economy. However current widely used generation scheduling model based on predefined production quota and tariff results in heavy energy consumption and severe environment pollution. From...... 2007, as concerns over energy shortage and environmental pollution, the Chinese authorities introduced the implementation of energy-saving generation dispatching model, which is an important approach to facilitating energy-saving and reduction of pollutant emission. The objective of implementing energy......-saving generation dispatching model is to prioritize the use of renewable energy resources and new power plants with high efficiency without compromising power system security and reliability. This paper analyzes the necessity and feasibility of implementing energy-efficient and environmentally friendly generation...

Energy savings through self-backhauling for future heterogeneous networks

International Nuclear Information System (INIS)

Faruk, Nasir; Ruttik, Kalle; Mutafungwa, Edward; Jäntti, Riku

2016-01-01

Mobile operators face continuous challenge of enhancing network capacity and coverage so as to meet demand for ubiquitous high-speed mobile data connectivity. Unfortunately, these enhancements are typically accompanied by increased burden of network energy consumption. Heterogeneous network (HetNet) deployments of a large number of low power small base stations (SBS) to complement existing macro base stations is an approach that increases network capacity but potentially reduces overall network energy consumption. The SBS backhaul links in HetNets present a significant powering burden. In this paper, we show how self backhauling of SBS can reduce overall network power demand. A backhaul-energy consumption model is developed and used to investigate the energy efficiency of different backhauling options. We note that significant energy savings could be achieved through the use of self-backhauling when compared with the conventional microwave backhauling. The results presented would provide guidelines for energy- and cost-efficient backhaul implementation for future HetNets. - Highlights: • A backhaul-energy consumption model is developed. • Self backhauling of small base stations can reduce overall network power demand. • Energy saving strategy presented would relieved the burden on the power networks. • Results provide guidelines for energy and cost effective backhaul implementation.

Private Sector Savings

Directory of Open Access Journals (Sweden)

Pitonáková Renáta

2018-03-01

Full Text Available The majority of household savings are in the form of bank deposits. It is therefore of interest for credit institutions to tailor their deposit policy for getting finances from non-banking entities and to provide the private sector with the loans that are necessary for investment activities and consumption. This paper deals with the determinants of the saving rate of the private sector of Slovakia. Economic, financial and demographic variables influence savings. Growth of income per capita, private disposable income, elderly dependency ratio, real interest rate and inflation have a positive impact on savings, while increases in public savings indicate a crowding out effect. The inflation rate implies precautionary savings, and dependency ratio savings for bequest. There are also implications for governing institutions deciding on the implementation of appropriate fiscal and monetary operations.

Observation of a periodic runaway in the reactive Ar/O2 high power impulse magnetron sputtering discharge

Directory of Open Access Journals (Sweden)

Seyedmohammad Shayestehaminzadeh

2015-11-01

Full Text Available This paper reports the observation of a periodic runaway of plasma to a higher density for the reactive discharge of the target material (Ti with moderate sputter yield. Variable emission of secondary electrons, for the alternating transition of the target from metal mode to oxide mode, is understood to be the main reason for the runaway occurring periodically. Increasing the pulsing frequency can bring the target back to a metal (or suboxide mode, and eliminate the periodic transition of the target. Therefore, a pulsing frequency interval is defined for the reactive Ar/O2 discharge in order to sustain the plasma in a runaway-free mode without exceeding the maximum power that the magnetron can tolerate.

Does Daylight Saving Save Energy? A Meta-Analysis

OpenAIRE

Havránek, Tomáš; Herman, Dominik; Irsova, Zuzana

2016-01-01

The original rationale for adopting daylight saving time (DST) was energy savings. Modern research studies, however, question the magnitude and even direction of the effect of DST on energy consumption. Representing the first meta-analysis in this literature, we collect 162 estimates from 44 studies and find that the mean reported estimate indicates modest energy savings: 0.34% during the days when DST applies. The literature is not affected by publication bias, but the results vary systemati...

Joule-Thief Circuit Performance for Electricity Energy Saving of Emergency Lamps

Science.gov (United States)

Nuryanto Budisusila, Eka; Arifin, Bustanul

2017-04-01

The alternative energy such as battery as power source is required as energy source failures. The other need is outdoor lighting. The electrical power source is expected to be a power saving, optimum and has long life operating. The Joule-Thief circuit is one of solution method for energy saving by using raised electromagnetic force on cored coil when there is back-current. This circuit has a transistor operated as a switch to cut voltage and current flowing along the coils. The present of current causing magnetic induction and generates energy. Experimental prototype was designed by using battery 1.5V to activate Light Emitting Diode or LED as load. The LED was connected in parallel or serial circuit configuration. The result show that the joule-thief circuit able to supply LED circuits up to 40 LEDs.

Photovoltaic Impact Assessment of Smart Inverter Volt-VAR Control on Distribution System Conservation Voltage Reduction and Power Quality

Energy Technology Data Exchange (ETDEWEB)

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

2016-12-01

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

Effect of energy saving lights on power supply

NARCIS (Netherlands)

Timens, R.B.; Buesink, Frederik Johannes Karel; Leferink, Frank Bernardus Johannes

2012-01-01

Weak power supply networks are very sensitive to non-linear low power loads. Electronics in low power loads are non-linear, very basic, and consisting of a rectifier bridge and bulk capacitor, consuming current only in the peak of the supplied voltage. Due to the relative high power supply network

The impact of fuel temperature reactivity coefficient on loss of reactivity control accident

International Nuclear Information System (INIS)

Park, J. H.; Ryu, E. H.; Song, Y. M.; Jung, J. Y.

2012-01-01

Nuclear reactors experience small power fluctuations or anticipated operational transients during even normal power operation. During normal operation, the reactivity is mainly controlled by liquid zone controllers, adjuster rods, mechanical control absorbers, and moderator poison. Even when the reactor power is increased abruptly and largely from an accident and when reactor control systems cannot be actuated quickly due to a fast transient, the reactor should be controlled and stabilized by its inherent safety parameter, such as a negative PCR (Power Coefficient of Reactivity) feedback. A PWR (Pressurized Water Reactor), it is well designed for the reactor to have a negative PCR so that the reactor can be safely shut down or stabilized whenever an abrupt reactivity insertion into the reactor core occurs or the reactor power is abruptly increased. However, it is known that a CANDU reactor has a small amount of PCR, as either negative or positive, because of the different design basis and safety concepts from a PWR. CNSC's regulatory and safety regime has stated that; The PCR of CANDU reactors does not pose a significant risk. Consistent with Canadian nuclear safety requirements, nuclear power plants must have an appropriate combination of inherent and engineered safety features incorporated into the design of the reactor safety and control systems. A reactor design that has a PCR is quite acceptable provided that the reactor is stable against power fluctuations, and that the probability and consequences of any potential accidents that would be aggravated by a positive reactivity feedback are maintained within CNSCprescribed limits. Recently, it was issued licensing the refurbished Wolsong unit 1 in Korea to be operated continuously after its design lifetime in which the calculated PCR was shown to have a small positive value by applying the recent physics code systems, which are composed of WIMS IST, DRAGON IST, and RFSP IST. These code systems were transferred

Evaluation of the performance of combined cooling, heating, and power systems with dual power generation units

International Nuclear Information System (INIS)

Knizley, Alta A.; Mago, Pedro J.; Smith, Amanda D.

2014-01-01

The benefits of using a combined cooling, heating, and power system with dual power generation units (D-CCHP) is examined in nine different U.S. locations. One power generation unit (PGU) is operated at base load while the other is operated following the electric load. The waste heat from both PGUs is used for heating and for cooling via an absorption chiller. The D-CCHP configuration is studied for a restaurant benchmark building, and its performance is quantified in terms of operational cost, primary energy consumption (PEC), and carbon dioxide emissions (CDE). Cost spark spread, PEC spark spread, and CDE spark spread are examined as performance indicators for the D-CCHP system. D-CCHP system performance correlates well with spark spreads, with higher spark spreads signifying greater savings through implementation of a D-CCHP system. A new parameter, thermal difference, is introduced to investigate the relative performance of a D-CCHP system compared to a dual PGU combined heat and power system (D-CHP). Thermal difference, together with spark spread, can explain the variation in savings of a D-CCHP system over a D-CHP system for each location. The effect of carbon credits on operational cost savings with respect to the reference case is shown for selected locations. - Highlights: • We investigate benefits from using combined cooling, heating, and power systems. • A dual power generation unit configuration is considered for CCHP and CHP. • Spark spreads for cost, energy, and emissions correlate with potential savings. • Thermal difference parameter helps to explain variations in potential savings. • Carbon credits may increase cost savings where emissions savings are possible

Chapter 23: Combined Heat and Power Evaluation Protocol. The Uniform Methods Project: Methods for Determining Energy Efficiency Savings for Specific Measures

Energy Technology Data Exchange (ETDEWEB)

Kurnik, Charles W. [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Simons, George [Itron, Davis, CA (United States); Barsun, Stephan [Itron, Davis, CA (United States)

2017-11-06

The main focus of most evaluations is to determine the energy-savings impacts of the installed measure. This protocol defines a combined heat and power (CHP) measure as a system that sequentially generates both electrical energy and useful thermal energy from one fuel source at a host customer's facility or residence. This protocol is aimed primarily at regulators and administrators of ratepayer-funded CHP programs; however, project developers may find the protocol useful to understand how CHP projects are evaluated.

Transient voltage control of a DFIG-based wind power plant for suppressing overvoltage using a reactive current reduction loop