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IEEE Conference on Industrial Electronics and Applications (ICIEA)

作者： L.X. Zhou Z.D. Yin X.N. Xiao Z.Q. Wang L. Zheng Key Laboratory of Power System Protection and Dynamic Security Monitoring and Control under Ministry of Education North China Electric Power University Beijing China North China Power Grid Xingtai Power Supply Corporation Xingtai China

With the rapid development of electric electronic technology, non-linear loads, large capacity converters, etc. increase mostly, which brings about the serious problems such as harmonics. Thus, the traditional power theory based on the average is unable to meet with the practical require. In this paper, the power definition in the sinusoidal and non-sinusoidal circuit is discussed and the waveform similarity between voltage and current is analyzed due to the criterion of minimum mean square deviation. Furthermore, the relationships among the waveform similarity factor, displacement power factor and real power factor are also discussed. The results show that power components are well analyzed in use of waveform similarity under the conditions of non-sinusoidal. At the same time, waveform similarity provides a simple but effective method for the calculation of power factor.

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Study on assessment model of event-type power disturbances

Study on assessment model of event-type power disturbances

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IEEE Asia-Pacific Conference on Circuits and systems

作者： Xiangning Xiao Shun Tao Key Laboratory of Power System Protection and Dynamic Security Monitoring and Control North China Electric Power University Changping District Beijing P.R.China

This paper discussed the characteristics of power disturbances, and then proposed new classifying method. Disturbances are classified into two main categories, ldquocontinuous typerdquo and ldquoevent typerdquo. Continuous type disturbances typically include voltage deviation, power frequency deviation, unbalance, flicker and harmonics. Event type disturbances (ETD) include voltage sags (including short duration interruptions), outages, and transients. Based on the classification of power disturbances and traditional distribution reliability indices (SAIDI, CAIDI, SAIFI, CAIFI, and ASAI), Voltage sag indices coordinate interruption events indices were proposed: 1) SASDI and CASDI, 2) SASFI and CASFI. The comprehensive index ASAI*, a corrected ASAI, was defined based on SAIDI and SASDI coordinate of the economic losses of customers impacted by event type disturbances. The assessment model of ETD was proposed. The model represents the defined indices, the calculating procedure, the phase aggregation, and the time aggregation, which are four basic factors to rightly assessment power quality. A case study was used to testify the comprehensive method was reasonable and feasible.

关键词： power quality Frequency Voltage fluctuations power system transients monitoring power system reliability power system harmonics power system modeling Laboratories power system protection

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Neural Network Approaches to Unimodal Surjective Map Chaotic system Forecasting

Neural Network Approaches to Unimodal Surjective Map Chaotic...

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International Symposium on Intelligent Information Technology Application, IITA

作者： Yagang Zhang Po Zhang Xiaozhe Wang Zengping Wang Key Laboratory of Power System Protection and Dynamic Security Monitoring and Control under Ministry of Education North China Electric Power University Baoding China Center for Nonlinear Complex Systems Yunnan University Kunming China

The forecasting using neural networks in unimodal surjective map chaotic dynamic system will be studied carefully in this paper. And most of the forecasting precision has exceeded 90%. Because of the intrinsic property of chaos, the forecasting precision will decrease as the length of symbolic sequence is increasing. But in this place we have found a generating rule that may realize chaotic synchronization at least in short and medium term, and we can analysis and forecast in this way. Nonlinear dynamics maintain manifold links with biologic information system. We also hope to offer an effective prediction method to study certain properties of DNA base sequences, 20 amino acids symbolic sequences of proteid structure, and the time series that can be symbolic in finance market et al.

关键词： Neural networks Chaos Sequences Economic forecasting Nonlinear dynamical systems Information systems Prediction methods DNA Amino acids Finance

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Lessening zero sequence effects in dynamic voltage restorers

Lessening zero sequence effects in dynamic voltage restorers

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IEEE Asia-Pacific Conference on Circuits and systems

作者： Zhang zhi Yin zhongdong Zhang changyin Shang weidong Huang zhonghua Key Laboratory of Power System Protection and Dynamic Security Monitoring and Control North China Electric Power University Beijing China Kaifeng Power Supply Corporation Kaifeng China

This paper puts forward an analysis of the effects of zero sequence components on power devices in particularly on the dynamic voltage restorer (DVR) and gives simulation results. It is shown that four-wire DVR do better then the traditional three-wire DVR, unbalance voltage and zero sequence components can be lessened by four-wire DVR effectively, because it provides zero sequence current circuit. However, the interaction between DC-side and AC-side in this topology leads to an unbalance in the DC-link capacitor voltages and it causes zero sequence resonance especially when the DVR is under open loop control. But the closed loop control can provide additional damping to mitigate possible harmonic resonance. In this study, the DVR system is simulated by using PSCAD software. Simulation results are presented to verify the theoretical analysis.

关键词： power quality Voltage fluctuations power system restoration power system dynamics power system protection Analytical models Resonance Open loop systems power system harmonics PSCAD

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Using bacterial chemotaxis method for reactive power optimization

Using bacterial chemotaxis method for reactive power optimiz...

引用

Transmission and Distribution Exposition Conference: 2008 IEEE PES powering Toward the Future, PIMS 2008

作者： Huang, Wei Zhang, Cong Yang, Jingyan Zhang, Jianhua Liu, Zifa Wei, Zhilian Pan, Dongli Key Laboratory of Power System Protection and Dynamic Security Monitoring and Control North China Electric Power University Ministry of Education Dewai Zhuxinzhuang Beijing 102206 China

ISBN: (纸本)9781424419036

Reactive power optimization is one of the key problems in power system which makes the voltage quality and stability improved and the loss of the power system reduced. This paper briefly analyzes the limitation of some reactive power optimization methods for power system and then a more effective method based on bacterial colony chemotaxis is proposed to solve this problem which is a discrete, many variables and nonlinear programming one. We adjust the bacterial colony chemotaxis model to fit the reactive power optimization calculation and make an improvement of it to enhance its convergence speed and search efficiency. This method applies to the IEEE-30, IEEE-57, IEEE-118 bus system, and the result proves the practicability and validity of this method. Compared with SGA and CPSO optimal method, the simplicity and robustness of the process of bacterial colony chemotaxis suggest a research direction which is worth to move on. ©2008 IEEE.

关键词： Nonlinear programming

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Study of reactive power optimization based on Artificial Immune Ant Colony Algorithm

Study of reactive power optimization based on Artificial Imm...

引用

International Conference on Electric Utility Deregulation and Restructuring and power Technologies (DRPT)

作者： Siqing Sheng Jing Li Key Laboratory of Power System Protection and Dynamic Security Monitoring and Control under Ministry of Education North China Electric Power University Baoding Hebei China Student power system and itns automation North China Electric Power University Baoding Hebei China

This paper presents an algorithm for optimizing reactive power using Artificial Immune Ant Colony Algorithm. This hybrid algorithm uses artificial immune algorithm (AIA) to give pheromone to distribute and makes use of Ant Colony Algorithm (ACA) to give the optimal solution. The ACA has been improved. The improved ACA uses the best and worst ant to update the pheromone trails and pseudorandom proportional rule. Local pheromone update mechanism, pheromone limitation and adaptive pheromone decay coefficient are increased. The objective function of the proposed algorithm is to minimize the system active power loss. This algorithm has been applied to practical IEEE 30-bus system and shows better results and convergence rate as compared to other optimal methods.

关键词： Reactive power Ant colony optimization power system security power system stability Propagation losses Constraint optimization Feedback power system protection power system dynamics Mathematical model

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Mathematical model of new bi-directional DC-AC-DC converter for supercapacitor energy storage system in photovoltaic generation

Mathematical model of new bi-directional DC-AC-DC converter ...

引用

International Conference on Electric Utility Deregulation and Restructuring and power Technologies (DRPT)

作者： Yun Zhong Jiancheng Zhang Gengyin Li Xindi Yuan Key Laboratory of Power System Protection and Dynamic Security Monitoring and Controlunder Ministry of Education North China Electric Power University Baoding Hebei China

Energy storage system is an all-important part in photovoltaic. A new bidirectional DC-AC-DC converter for supercapacitor energy storage system in photovoltaic generation is put forward. In the beginning, some experiments on super capacitor have been performed, which shows super capacitor has good performance in quick charge and discharge. And mathematical model of the dual full-bridge bidirectional DC-AC-DC converter circuits with a transformer and its simplified model are derived. In the end, A phase current in the transformer primary side (ia) can be investigated with mathematical calculation simulation and detailed circuit simulation. The comparative result shows the mathematical model rationality. Through deduction, unified model of SESS also can be gotten.

关键词： Mathematical model Bidirectional control Supercapacitors Energy storage Photovoltaic systems Solar power generation Capacitors power transformer insulation Circuit simulation power generation

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Adaptive ant colony algorithm based on cloud model and its application in power distribution network planning

引用

Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering 2008年第SUPPL.期28卷 52-57页

作者： Xie, Qing Li, Yan-Qing Peng, Peng Wang, Ling Liu, Wen-Cai Lu, Fang-Cheng Key Laboratory of Power System Protection and Dynamic Security Monitoring and Control Min. of Edu. North China Electric Power University Baoding 071003 China Guangdong Power Grid Corporation Guangzhou 510600 China Beijing National Railway Research and Design Institute of Signal and Communication Fengtai District Beijing 100073 China

The distribution network structure planning can enhance the reliability and the efficiency of the grid. An adaptive ant colony algorithm based on cloud model was proposed and applied in distribution network structure planning in this paper. In view of the main disadvantage of being inclined to local convergence and slow convergence speed of traditional ant colony algorithm, the parameter ρ and Q were qualitatively controlled and dynamically selected in this paper by employing the uncertain qualitative association rule inference based on cloud model, which is one indefinite model for transformation between qualitative and quantitative knowledge. The algorithm overcomes the shortcoming of traditional ant colony algorithm, and the simulation results of power distribution network planning demonstrated the efficiency of the algorithm.

关键词： Efficiency

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Study on assessment method of load’s disturbance property

Study on assessment method of load’s disturbance property

引用

International Conference on Electric Utility Deregulation and Restructuring and power Technologies (DRPT)

作者： Xiufang Jia Zhang bo Liu Fazhan Sun Minghao Key Laboratory of Power System Protection andDynamic Security Monitoring and Control under Ministry of Education North China Electric Power University Baoding Hebei China Zhengzhou Power Supply Company Zhengzhou Henan China

Assessment of load's disturbing property needs to be studied for confirming power quality responsibility and making a power price by its quality. In this paper, load's disturbing property is assessed by means of the analytic hierarchy process (AHP) and the grey relational analysis (GRA). First, the weight of index such as power factor, current total harmonic distortion, unbalance factor and reactive power fluctuation, which can characterize load's property, is obtained by AHP method. In order to assess the degree of load disturbance, a standard load in power system is defined. Then, based on the GRA, can get relativity degree between each disturbing load and standard load. Relativity degree can describe the gap between each disturbing load and standard load. The degree that disturbing loads creates influence to the electrical network is known by means of relativity degree. Finally, calculating examples are brought forth to validate feasibility of the method.

关键词： power quality Voltage power supplies Reactive power Sun Total harmonic distortion power system economics power generation economics Environmental economics Circuit simulation

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A VSC-HVDC fuzzy controller to damp oscillation of AC/DC power system

A VSC-HVDC fuzzy controller to damp oscillation of AC/DC pow...

引用

IEEE International Conference on Sustainable Energy Technologies, ICSET

作者： Chunye Li Sheng Li Fuchun Han Jingfu Shang Ermin Qiao College of Electrical and Power Engineering Taiyuan University of Technology Taiyuan China Key Laboratory of Power System Protection and Dynamic Security Monitoring and Control Ministry of Education Beijing China China Electrical Power Research Institute China

The fast control capability of the VSC-HVDC and the process of area mode oscillations are analyzed. An auxiliary fuzzy logic controller designed in Matlab for the voltage source converter based HVDC transmission system, VSC-HVDC, to improve the stability of the AC/DC system is designed to enhance stability by increasing the deceleration energy of oscillation. Simulation results on the IEEE 4-generator AC/DC power systems have shown that the controller can enhance the dynamic stability of interconnected power systems effectively and is robust to the variation of system operating conditions and oscillation modes.

关键词： Fuzzy control Fuzzy systems control systems power systems power system stability Converters power conversion power system simulation power system interconnection power system dynamics

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