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International power Engineering Conference (IPEC)

作者： Ming-yu Yang Wan-ye Yao Zeng-ping Wang Ju Zhang Yan-jun Jiao Key Laboratory of Power System Protection and Dynamic Security Monitoring and Control under Ministry of Education North China Electric Power University Baoding Hebei China Automation Department North China Electric Power University Baoding Hebei China

ISBN: (纸本)9810557027

A new ultra high-speed protection scheme is proposed in this paper. Using wavelet transform with multiresolution analysis, the current signals is decomposed into a series of detailed wavelet components. The spectral energies of the wavelet components are calculated and then employed to detect the faults. Characteristics of the proposed ultra high-speed protection algorithm are analyzed and results of simulation studies are given. The results show that the proposed algorithm is promising and easy to implement for computer relaying application

关键词： protection Wavelet analysis Wavelet transforms Multiresolution analysis Fault detection Algorithm design and analysis Computational modeling Analytical models Computer applications Protective relaying

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A new protection algorithm for EHV transmission line based on singularity detection of fault transient voltage

A new protection algorithm for EHV transmission line based o...

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International power Engineering Conference (IPEC)

作者： Ming-yu Yang Wan-ye Yao Zeng-ping Wang Yan-jun Jiao Ju Zhang Key Laboratory of Power System Protection and Dynamic Security Monitoring Control under Ministry of Education North China Electric Power University Baoding Hebei China Automation Department of North China Electric Power University Baoding Hebei China

ISBN: (纸本)9810557027

A new non-unit voltage protection algorithm for extra high voltage (EHV) transmission lines is presented in this paper. The singularity of fault transient voltage signals in one terminal is utilized to discriminate clearly between internal and external faults. Lipschitz exponent (LE) is obtained from wavelet modulus maximum to detect singularity of signals. A typical 500 kV EHV transmission system has been simulated by ATP to evaluate the scheme. The simulation results show that this scheme is capable of providing correct responses under various system configurations and fault conditions

关键词： Transmission lines Fault detection power system transients Voltage power system protection power transmission lines Wavelet transforms Circuit faults Signal detection Frequency

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power Quality Control Center and Its Control Method

Power Quality Control Center and Its Control Method

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IEEE/PES Transmission and Distribution Conference and Exhibition: Asia and Pacific

作者： Peng Li Qian Bai Baoli Zhao Yihan Yang Key Laboratory of Power System Protection and Dynamic Security Monitoring and Control under Ministry of Education North China Electric Power University Baoding Hebei China Baoding Baoling Transformer Company Limited Baoding Hebei China

power quality becomes an emphasis of related researches. Based on the detailed study on QCC (quality control center) of the FRIENDS first advanced by Japanese scholars, the functions of QCC are expanded and its basic types and structures are defined. Meanwhile, by detailed study, this paper introduces the multiple adjusting functions of UPQC (unified power quality conditioner) which is the chief part of QCC and presents its typical topological circuit. Moreover, H infin control technology is used to realize the synthesis tracking compensation of voltage and current for UPQC. Finally its validity has been testified successfully

关键词： power quality power supplies power system reliability Automatic control Energy management Quality management Communications technology Quality control power system management power generation economics

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Data Envelopment Analysis Based Strategy of Assessing Schemes for power system Black Start

Data Envelopment Analysis Based Strategy of Assessing Scheme...

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IEEE/PES Transmission and Distribution Conference and Exhibition: Asia and Pacific

作者： Liu Yan Gu Xueping Zhang Dan Laboratory of Power System Protection and Dynamic Security Monitoring and Control under Ministry of Education North China Electric Power University Baoding Hebei China Dispatching Center of Yunnan Power Company Kunming China

Restoration of a power system after a complete blackout is a very important issue to the safety of the power system. Reasonable black start schemes are necessary to restore the power system as soon as possible. Based on data envelopment analysis, a new strategy for assessing black start schemes is proposed in this paper. Schemes' technical verification is taken into consideration in the process of the assessment. Whether a scheme is effective is defined by employing its input and output indexes' values entirely. The application to a practical power system verifies that the method could provide dispatchers more comprehensive and objective decision references

关键词： Data envelopment analysis power system analysis computing power system restoration power system reliability power system protection power system economics power system faults power system measurements Safety Control systems

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Risk Management on Long-term Electricity Purchase Allocation in China power Markets

Risk Management on Long-term Electricity Purchase Allocation...

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International Conference on power Electronics and Drive systems (PEDS)

作者： Ming Zhou Gengyin Li Yanli Nie Yixin Ni Key Laboratory of Power System Protection and Dynamic Security Monitoring and Control under Ministry ofEducation North China Electric Power University Baoding Hebei China Department of Electrical and Electronic Engineering University of Hong Kong Hong Kong China

This paper presents an integrated framework for the optimal management of electricity purchase allocation and risk for load service entities (LSEs). To the practice of China power Markets, we propose the framework of power portfolio of combined physical forward contract and spot market. The framework suggests that the forward contracts should have different prices on-peak and off-peak in accord with sale prices distinguish on-peak and off-peak. The optimal purchase problem is described by the utility maximum integrated the rate of return and risk tolerance level, and risk is evaluated by Value at Risk (VaR). The analytical solution is also conducted. The numerical results are reasonable with higher rate of return and better risk hedging compared with the corresponding results from the existing portfolio selection approach. The presented framework gives one possible and effective method for the optimal power portfolio and risk management in incomplete power markets.

关键词： Risk management power markets Portfolios Forward contracts Electricity supply industry Pricing Marketing and sales Energy consumption power generation Scheduling

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power Quality Disturbance Detection Based on Mathematical Morphology and Fractal Technique

Power Quality Disturbance Detection Based on Mathematical Mo...

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IEEE/PES Transmission and Distribution Conference and Exhibition: Asia and Pacific

作者： Gengyin Li Ming Zhou Yan Luo Yixin Ni Key Laboratory of Power System Protection and Dynamic Security Monitoring and Control under Ministry of Education North China Electric Power University Baoding Hebei China Department of Electrical and Electronic Engineering University of Hong Kong Hong Kong China

Based on mathematical morphology and grille fractal, a novel approach on power quality disturbance detection and location is presented in this paper. At first a parallel composite morphological filter with multiple-structure elements is designed to filter the random noise and impulse noise in power quality disturbance signals. Then to the filtered curves, an easy implementation criterion for singularity detection based on the change regularity of grille fractal is proposed to locate the start and end time that disturbance occurs. The voltage sag, swell, harmonic and their combined disturbances are used to verify the validity of the proposed filter-location approach. Numerical results show that the proposed approach is valid and effective

关键词： power quality Morphology Fractals power harmonic filters Signal sampling Signal analysis Shape Educational programs Noise shaping Voltage fluctuations

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Real time detection method for any integral harmonic voltage based on instantaneous reactive power theory

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Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering 2005年第18期25卷 70-73页

作者： Sun, Cai-Hua Zong, Wei He, Lei Du, Ning Li, Hai-Yan Key Laboratory of Power System Protection and Dynamic Security Monitoring and Control North China Electric Power University Beijing 102206 China

In order to implement real time detection of harmonic voltage, a method for any harmonic voltage detection based on instantaneous reactive power theory was presented. In the detection the standard current signals were additional, so the detection precision was not affected by the distorted system current and the detection results could also reflect the changes of frequency shift. To make the dynamic response speed quicker, an algorithm with feedback compensation was presented. The simulation results show that the algorithm can quicken the dynamic response speed effectively, the feedback compensation value also has a bigger effect on the response speed and detection precision, and the detection performance are not affected by frequency shift.

关键词： Signal detection

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Integrating Radial Basis Function Neural Network with Fuzzy Control for Load Forecasting in power system

Integrating Radial Basis Function Neural Network with Fuzzy ...

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IEEE/PES Transmission and Distribution Conference and Exhibition: Asia and Pacific

作者： Siqing Sheng Cong Wang Laboratory of Power System Protection and Dynamic Security Monitoring and Control under Ministry of Education North China Electric Power University Baoding Hebei China School of Electrical Engineering North China Electric Power University Baoding Hebei China

Short-term load forecasting of power system is not only the basis of scheduling of generating sets, but also the basis of working out the transaction schedule in electricity market. This paper proposes a short-term load forecasting method based on combination of radial basis function (RBF) neural network and fuzzy control, uses on-line self-modify factor fuzzy control to eliminate forecast error on the basis of RBF neural network forecasting. The practical examples show that the accuracy of short-term load forecasting and training speed can be improved and gains the very satisfactory results by the proposed method

关键词： Radial basis function networks Fuzzy control Load forecasting power system control power systems Neural networks Economic forecasting power generation Electricity supply industry Error correction

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Experimental study on the ion migration of DC support ceramic insulators

Experimental study on the ion migration of DC support cerami...

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Electrical Insulation Conference and Electrical Manufacturing & Coil Winding Conference

作者： Chengrong Li Bo Qi Zhi yi Shu Beijing Key Laboratory of High Voltage & EMC Key Laboratory of Power System Protection and Monitoring and ControlMinistry of Education North China Electric Power University Beijing China Electric Power Research Institute Inc. Beijing China

A ion migration testing for DC ceramic support insulators was designed and conducted in this paper. After the long-term ion migration testing, the change of Na + distribution in the tested samples was analyzed, and the mechanical performance of the tested samples was verified. It is indicated from our results that the ion migration testing in our laboratory doesn't influence the mechanical performance for the ceramic support insulators

关键词： Ceramics Insulator testing Voltage Dielectrics and electrical insulation Electrodes Laboratories IEC standards Transmission line measurements Materials testing Measurement standards

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New algorithm based on the mathematical morphology for avoiding mal-operation of transformer differential protection

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Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering 2005年第20期25卷 6-11页

作者： Zheng, Tao Liu, Wan-Shun Liu, Jian-Fei Xiao, Shi-Wu Laboratory of Power System Protection and Dynamic Security Monitoring and Control North China Electric Power University Beijing 102206 China

To avoid the mal-operation of transformer differential protection when out-zone fault occurs under current transformer (CT) saturation, a new algorithm based on the mathematical morphology is put forward in this paper. Unlike the traditional time-differential method, which is based on the time difference between fault occurrence and the differential current increase, this algorithm only needs detecting the time of fault occurring, while the time of differential current increasing is no more needed. A new current waveform is obtained by a symmetrical transformation of the initial part of differential current after fault occurred, and then its characteristic is extracted by morphological gradient. In the case of CT's serious saturation, a discrimination of out-zone fault and inner-zone fault can be clearly made by this algorithm, which needs a little calculation and a short data window. Simulation results of EMTP validate its feasibility and reliability.

关键词： Transformer protection

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