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作者： Xiao, Jun Zhai, Wei Gu, Wenzhuo Key Laboratory of Power System Simulation and Control of Ministry of Education Tianjin University 300072 China

ISBN: (纸本)9781457700668

This paper proposes the definition, model and algorithm of two quantitative indices named the Total Supply Capability (TSC) and Ideal Total Supply Capability (ITSC) for distribution planning. The TSC of a distribution system is comparable to Total Transfer Capability (TTC) in transmission systems, which is defined as the maximum load it can serve under the N-1 guideline for distribution systems, taking into account the capacities of the substation transformers, network link topology, link capacity, and other constraints. The ITSC of a distribution system is the calculated TSC which considers capacities of tie lines are large enough. Mathematical models for TSC and ITSC are set up and procedures to calculate TSC and ITSC are presented. Based on TSC and ITSC calculation, a concept named Potential Supply Capability(PSC) is proposed, which depicts the "potential" or "hidden" TSC of the distribution system. Finally, TSC and ITSC calculation have been performed in a test system with promising results. The case study has shown that TSC and ITSC algorithms are efficient approaches to analyze and evaluate the existing distribution system. © 2010 Chinese Soc for Elec Eng.

关键词： Electric utilities

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Discussion on setting calculation of loss-of-excitation protection for large turbogenerator

Discussion on setting calculation of loss-of-excitation prot...

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作者： Yao, Siwang Wang, Weijian Luo, Ling Gui, Lin Qiu, Arui State Key Laboratory of Control and Simulation of Power System and Generation Equipments Department of Electrical Engineering Tsinghua University Beijing China

ISBN: (纸本)9788986510119

Loss of excitation (LOE) is a common fault found in the generators. The most widely applied method for detecting a generator loss of excitation is the use of impedance relays to sense the variation of impedance as viewed from the generator terminals [1]. However, compared with China's approachs, in the setting of impedance circle, the IEEE's allow the circle to extend along the negative X axis, meanwhile, in the latest edition of the "IEEE Guide for AC Generator Protection", the circle is further extended, reaching to -*** think this is adverse, to prove our point, the paper ,basing on the IEEE 9 bus model and using computer digital simulation, have studied various loss-of-excitation conditions and some system disturbances that may lead to the relay false tripping. simulation results indicate that the IEEE's method not only can't accelerate the operation effectively, but also will increase the chances of maloperation.

关键词： Electric equipment protection

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Modeling and simulation of grid-connected hybrid photovoltaic/battery distributed generation system

Modeling and simulation of grid-connected hybrid photovoltai...

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作者： Ding, Fei Li, Peng Huang, Bibin Gao, Fei Ding, Chengdi Wang, Chengshan Key Laboratory of Power System Simulation and Control of Ministry of Education Tianjin University Tianjin 300072 China

ISBN: (纸本)9781457700668

Photovoltaic(PV)generation is the technique which uses photovoltaic cell to convert solar energy to electric energy. Nowadays, PV generation is developing increasingly fast as a renewable energy source. However, the disadvantage is that PV generation is intermittent for depending on weather conditions. Thus, the battery energy storage is necessary to help get a stable and reliable output from PV generation system for loads and improve both steady and dynamic behaviors of the whole generation system. The paper presents detailed transient models of the grid-connected PV/Battery hybrid generation system, and all these models are simulated by using MATLAB/Simulink. PV array is firstly connected to the common dc bus by a boost converter, where the battery is also connected by a bi-directional DC/DC converter, and then integrated into the ac utility grid by a common DC/AC inverter. Maximum power point tracking helps PV array to generate the maximum power to the grid, and the battery energy storage can be charged and discharge to balance the power between PV generation and utility grid. Finally, different cases are simulated, and the results have verified the validity of models and control schemes. © 2010 Chinese Soc for Elec Eng.

关键词： Solar energy

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Analysis on the negative sequence impedance directional protection for stator internal fault of turbo generator

Analysis on the negative sequence impedance directional prot...

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作者： Hao, Liangliang Sun, Yuguang Arui, Qiu State Key Laboratory of Control and Simulation of Power System and Generation Equipments Department of Electrical Engineering Tsinghua University Beijing 100084 China

ISBN: (纸本)9788986510119

In order to protect more turn-to-turn faults for the turbo-generator with only three lead-out terminals in the neutral side, this paper applies a new principle protection - negative sequence impedance directional protection of fault components for stator internal asymmetrical fault. By means of Multi-loop Method, all possible internal short-circuit faults and single branch shutdown faults of a 300MW turbo-generator are calculated to obtain the protection performance. Calculation and performance analysis show that, this new principle protection is superior to other existing protections in the aspect of sensitivity and protection range, especially for interturn faults of turbogenerator stator winding. In addition, it won't incorrectly trip on external faults. Thus, this new principle protection can provide safeguard of high quality for internal faults in turbo-generator with only three lead-out terminals in the neutral side.

关键词： Stators

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Design and implementation of the high efficiency photovoltaic system with solid state lighting

Design and implementation of the high efficiency photovoltai...

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作者： Hu, Xianlai Yuan, Liqiang Chen, Jian Zhao, Zhengming State Key Laboratory of Control and Simulation of Power System and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing 100084 China

ISBN: (纸本)9788986510119

Photovoltaic application of LED lighting has been a hot trend in residential illumination, for it integrates the advantages of both the PV systems and LED lights. However, it has a series of problems, such as high thermal loss, poor reliability, and a short life span. To address these problems, this paper presents a deep research on the whole system from a low-cost, high-efficiency and long-life point of view. A main circuit integrating maximum power point tracing (MPPT) control and battery management, as well as a double-loop control for LED load is developed. A set of protection system is applied to ensure high reliability of the system. The control strategies are tested on the demonstrator and prove to be effective.

关键词： Integrating circuits

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Experiment on influence factors and variety rules of spark plug ion-current signals amplitude

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Jilin Daxue Xuebao (Gongxueban)/Journal of Jilin University (Engineering and Technology Edition) 2011年第SUPPL. 1期41卷 41-46页

作者： Sun, Yue-Guo Yuan, Zhao-Cheng Liu, Chong Li, Li-Ying State Key Laboratory of Automotive Simulation and Control Jilin University Changchun 130022 China Weichai Power Co. Ltd. Weifang 261001 China School of Computer Science Jilin Normal University Siping 136000 China

By optimizing the detecting circuit of spark plug ion-current, the high frequency and high voltage interference generated by the high ignition was successfully controlled and the stable ion-current signals within the range of 0.3~3.2 V were obtained. In the testing process, three kinds of spark plugs were used and their ion-current signals at different engine operating condition (different engine speeds and loads) were gathered. By comparing these three different signals, it is obvious that the ion-current amplitude is influenced by spark plug's parameters, and also generally is intense with the increase of engine speed and load. And finally, the influences of spark plug parameters on ion-current signal amplitude were analyzed.

关键词： Ions

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Discussion on setting calculation of loss-of-excitation protection for large turbogenerator

Discussion on setting calculation of loss-of-excitation prot...

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2010 International Conference on Electrical Machines and systems, ICEMS2010

Loss of excitation (LOE) is a common fault found in the generators. The most widely applied method for detecting a generator loss of excitation is the use of impedance relays to sense the variation of impedance as viewed from the generator terminals [1]. However, compared with China's approachs, in the setting of impedance circle, the IEEE's allow the circle to extend along the negative X axis, meanwhile, in the latest edition of the "IEEE Guide for AC Generator Protection", the circle is further extended, reaching to -1.25X_d.We think this is adverse, to prove our point, the paper ,basing on the IEEE 9 bus model and using computer digital simulation, have studied various loss-of-excitation conditions and some system disturbances that may lead to the relay false tripping. simulation results indicate that the IEEE's method not only can't accelerate the operation effectively, but also will increase the chances of maloperation.

关键词： Impedance Generators Relays Analytical models power system stability Reactive power

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Reactive power compensation devices optimization based on improved ant colony algorithm

Reactive power compensation devices optimization based on im...

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International Conference on Electrical and control Engineering, ICECE 2010

作者： Jiang, Huilan He, Ming Liu, Lin Ji, Huiqiang Shan, Dapeng Key Laboratory of Power System Simulation and Control of Ministry of Education Tianjin University Tianjin 300072 China Tianjin High Voltage Power Supplied Company Tianjin 300250 China

ISBN: (纸本)9780769540313

In the assumption that all load nodes are installed reactive power compensation device, injecting a variety of disturbances to the grid, through the application of improved ant colony algorithm, we can obtain the optimal control sequence under disturbance, that is current switching reactive power compensation device node location. Comparing control sequences under the various perturbations, with circulation mechanism of successive exclusion, the best installation location of reactive power compensation devices is obtain, while the system voltage deviation smaller, improving power system operation economy. In this paper, there is a planning example, the results show that the proposed method is feasible. © 2010 IEEE.

关键词： Electric power utilization

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Optimal speed control system of generator based on chaotic particle swarm optimization

Optimal speed control system of generator based on chaotic p...

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International Conference on Electrical and control Engineering, ICECE 2010

作者： Jiang, Huilan Liu, Yang Liu, Lin Ji, Huiqiang Shan, Dapeng Key Laboratory of Power System Simulation and Control of Ministry of Education Tianjin University Tianjin 300072 China Tianjin High Voltage Power Supplied Company Tianjin 300250 China

ISBN: (纸本)9780769540313

In view of real-time and operational requirements of the speed control system for generating, the method of determining the traditional PID control parameters seriously affected by the operator due to the use of the experience, not accurate enough. This paper proposed chaotic particle swarm optimization (PSO) and adjustment methods based on the traditional PID in the electro-hydraulic control, establish the state equation of the speed control system, and thus to design generator speed control system based on chaotic particle swarm optimization algorithm. The simulation experiments show that the regulator has better robustness and real-time compared to the traditional PID control method, and can provide optimal control in the light of the different types of the running point and the interference. © 2010 IEEE.

关键词： Three term control systems

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An improved under frequency load shedding scheme based on rate of change of frequency

An improved under frequency load shedding scheme based on ra...

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International Conference on Electrical and control Engineering, ICECE 2010

作者： Jiang, Huilan Yan, Geng Ji, Huiqiang Liu, Lin Shan, Dapeng Key Laboratory of Power System Simulation and Control of Ministry of Education Tianjin University Tianjin 300072 China Tianjin High Voltage Power Supplied Company Tianjin 300250 China

ISBN: (纸本)9780769540313

In allusion to the traditional UFLS scheme's deficiencies of changeless frequency setting value and amount of load shedding of every run, this paper proposes improved UFLS scheme which can alter the frequency setting value of the first run and the amount of load shedding of every run dynamically according to the magnitude of frequency change rate, namely the insufficient amount of active power. The simulation results of stand-alone model show that the reformative UFLS scheme can restrain the frequency falling depth effectively, fit speed controller preferably, make full use of system rotating spare capacity, and reduce the amount of load shedding and the possibility of over-cut or owes-cut. © 2010 IEEE.

关键词： Electric load shedding

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