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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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A new ultra high-speed protection scheme based on wavelet analysis

A new ultra high-speed protection scheme based on wavelet an...

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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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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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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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Research on the performance of wavelet packet transform based non-unit transient current protection

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Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering 2005年第SUPPL.期25卷 151-156页

作者： Wang, Zeng-Ping Liu, Hao-Fang Laboratory of Power System Protection and Dynamic Security Monitoring and Control North China Electric Power University Baoding 071003 China

The reflection and refraction of fault-generated wave on EHV lines were investigated and the equations of transient current detected by relay were deduced. Theoretical analysis shows that the protection based on the energy ratio of higher frequency components is more adaptive to various faults and can distinguish between the internal and external faults near the remote busbar more effectively. Such protection also has similar performance when used on EHV lines and series compensated EHV lines. The wavelet packet transform technique was employed to determine the energy ratio. Simulation results show that the proposed conclusions are correct.

关键词： Electric lines

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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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Power system cascading outages assessment based on support vector machine

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Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering 2005年第SUPPL.期25卷 178-183页

作者： Deng, Hui-Qiong Ai, Xin Liu, Hao Laboratory of Power System Protection and Dynamic Security Monitoring and Control North China Electric Power University Beijing 102206 China

A method of power system cascading outages assessment based on support vector machine (SVM) was provided in this paper. Taking full advantages of the ability of SVM to solve the problem with small sample, nonlinear and high dimension, this method constructs an assessment mode which uses resampling classification technique based on boosting method, pretreatment technique based on distance criterion and information fusion technique. This mode can help to improve the precision and stability of assessment, hence better generalization ability of assessment is guaranteed. At the end of this paper, an example is provided to demonstrate the validity of the proposed approach.

关键词： Electric power system protection

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Applied clusters and entropy in discreting attributes of load forecasting

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Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering 2005年第SUPPL.期25卷 65-70页

作者： Li, Jing-Hua Li, Ran Li, He-Ming Gu, Xue-Ping Laboratory of Power System Protection and Dynamic Security Monitoring and Control North China Electric Power University Baoding 071003 China

Attributes are require to be discrete when using data mining methods to establish forecasting model, for example, rough set, ANN and decision tree. But most discrete methods used before can't consider the relationship of conditional and decision attributes well, so the discrete results are not very satisfaction. This paper presents a new discrete method which combines clusters and entropy. First, cluster is adopted to get the waiting breakpoints. Then finally results are decided by their rate of entropy. According to clustering, the boundary value is greatly reduced. Meanwhile, through entropy which considers the condition attributes and decision attributes, attributes can be discreted more exactly. At last, the discrete results compared with the method based on the importance of breakpoints show that the proposed method assurance the quality of classing. The space of sample can be compressed effectively, which lightens the training load of model and the gotten rules are with good adaptability and useful value. The correctness and effectiveness are validated by the practical application and the accuracy of forecasting will be increased.

关键词： Electric load forecasting

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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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Research on Remote Meter Automatic Reading Based on Computer Vision

Research on Remote Meter Automatic Reading Based on Computer...

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

作者： Shutao Zhao Baoshu Li Jinsha Yuan Guiyan Cui Key Laboratory of Power System Protection and Dynamic Security Monitoring and Control under Ministry of Education North China Electric Power University Baoding Hebei China Electrical Communication Department North China Electric Power University Baoding Hebei China North China Electric Power University Baoding Hebei China

A novel method is put forward, which the power meter can be read based on compute vision, and the architecture of remote meter auto reading system is designed. Different with the normal automatic meter reading system that must obtain the value from digital communication interface, the new method recognizes the meter reading utilizing the computer vision technique, it is a kind of non-contact measurement. In the meter automatic reading, the computer vision discrimination, incorporate human's ability of visual and apprehensive models. Not only the digital display power meter can be read, but also the direct-reading instrument can be fetched. In this paper, the scheme of remote automatic reading is introduced, the local meter reading information of distributed substation can be transmitted to center using computer network and then the pretreatment, segmentation and pattern matching, are detailed description in the meter image recognition process. Via energy meter automatic recognition experiment, the results based computer vision is accurate enough to monitor the remote substation running parameters

关键词： Computer vision Meter reading Substations Computer architecture Automatic meter reading Digital communication Power system modeling Computer displays Instruments Computer networks

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