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2005 IEEE/PES Transmission and DistributionConference and Exhibition - Asia and Pacific

作者： Gao, Yajing Zhou, Ming Li, Gengyin Huang, Yuekui Xiao, Limin Li, Rui IEEE Laboratory of Power System Protection and Dynamic Security Monitoring and Control Ministry of Education North China Electric Power University Baoding 071003 Hebei Province China Hebei Electric Power Company Shijiazhuang 050021 Hebei Province China

ISBN: (纸本)0780391144

With the further development of power markets, large amount of electric power wheeling and frequent transmission transaction is emerging, accurately determining Available Transmission Capability (ATC) and broadcasting the ATC information in time are very important to prevent and relieve transmission congestion effectively. In practical power markets, there are large amount of uncertainties involved in Transmission Reliability Margin (TRM) and Capacity Benefit Margin (CBM) of ATC. Considering calculation accuracy and time, a novel approach is proposed to calculate ATC based on Monte Carlo simulation and sensitivity analysis considering large amount of uncertainties impacting the value of ATC. The steady state constraints and voltage stability and transient stability constraints are taken into account. The iterative solution based on PSASP by China EPRI is developed. IEEE 14-bus test system is used to verify the presented approach. The results show that the model and algorithm is correct and effective. The research achievements are undergoing to transfer to the application in certain provincial power system in China, and some new problems are suggested in the end of paper. © 2005 IEEE.

关键词： power transmission

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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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2005 IEEE/PES Transmission and DistributionConference and Exhibition - Asia and Pacific

作者： Li, Gengyin Zhou, Ming Luo, Yan Ni, Yixin IEEE Key Laboratory of Power System Protection and Dynamic Security Monitoring and Control Ministry of Education North China Electric Power University Baoding 071003 Hebei Province China Department of Electrical and Electronic Engineering University of Hong Kong Hong Kong Hong Kong

ISBN: (纸本)0780391144

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. © 2005 IEEE.

关键词： Electric power distribution

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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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Sixth International Conference on power Electronics and Drive systems, PEDS 2005

作者： Zhou, Ming Li, Gengyin Nie, Yanli Ni, Yixin Key Laboratory of Power System Protection and Dynamic Security Monitoring and Control under Ministry of Education North China Electric Power University Baoding 071003 Hebei Province China Department of Electrical and Electronic Engineering University of Hong Kong Hong Kong Hong Kong

ISBN: (纸本)0780392965

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. © 2005 IEEE.

关键词： Risk management

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The research of electric appliance running status detecting based on DSP

The research of electric appliance running status detecting ...

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2005 IEEE/PES Transmission and Distribution Conference and Exhibition: Asia and Pacific

作者： Li, Baoshu Quan, Chao Zhao, Shutao Tong, Weiguo Tao, Peng Key Laboratory of Power System Protection and Dynamic Security Monitoring and Control Ministry of Education North China Electric Power University Baoding 071003Hebei Province China Electrical Engineering Department North China Electric Power University Baoding 071003 China North China Electric Power University Baoding 071003 China

ISBN: (纸本)0780391144

A new load detection method was presented based on its running status of power system. The loads are sorted according to their index of capacitive, inductive, and none-linear. The static character of each load was got according to the time-distribution. The concept of load detection is completed. The data-sample and wave recording equipment is designed and assembled based on the DSP for power loads status detecting. The superior software was designed for data management and analyzing. The recognizing status data was analyzed in both time-domain and frequency-domain;the identifying method for electric power loads status is deduced based on the correlation coefficient;the mathematical model for the status identifying is built;the trueness and validity of the methods is verified based on the testing and analyzing. © 2005 IEEE.

关键词： Electric power systems

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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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2005 IEEE/PES Transmission and Distribution Conference and Exhibition: Asia and Pacific

作者： Zhao, Shutao Li, Baoshu Yuan, Jinsha Cui, Guiyan Key Laboratory of Power System Protection and Dynamic Security Monitoring and Control Ministry of Education North China Electric Power University Baoding 071003 Hebei Province China Electrical Communication Department North China Electric Power University Baoding 071003 China North China Electric Power University Baoding 071003 China

ISBN: (纸本)0780391144

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. © 12005 IEEE.

关键词： Computer vision

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A Novel Structure of dynamic Reactive power Source

A Novel Structure of Dynamic Reactive Power Source

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

作者： Zhongdong Yin Jianhua Zhang Xiangning Xiao Zhengpai Cui Yunbo Long Key Laboratory of Power System Protection and Dynamic Security Monitoring and Control Ministry of Education North China Electric Power University China

This paper puts forward a novel topology of controllable reactor, the structure is based on many small capacity thyristor controlled reactor (TCR) modules and a three-windings transformer connecting to system. The transformer secondary adopts duplex winding structure and each has multi-bank TCR modules being in delta connection. In this topology, the harmonic current injected into the power system is very small. It not only possesses all the functions a traditional TCR has, but also has many other merits such as occupying small floor space, generating little loss, easy implement control and protection scheme, and high reliability etc. A 500 kVar industrial prototype is under construction in Langfang, Hebei province of ***. Digital simulation based on EMTDC/PSCAD and field test were carried out to verify the perfect harmonics characteristics of topology proposed

关键词： Reactive power Topology power system harmonics Control systems Inductors power system protection power system reliability PSCAD Thyristors Joining processes

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New algorithm based on the distribution of the normalized equivalent instantaneous inductance for the discrimination of inrush

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Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering 2005年第23期25卷 47-53页

作者： Zheng, Tao Liu, Wan-Shun Zhuang, Heng-Jian Li, Xiao-Bo Laboratory of Power System Protection and Dynamic Security Monitoring and Control North China Electric Power University Beijing 102206 China SP Longyuan Environment Engineering Beijing 100761 China

Oriented to wye-delta connected three phase transformer, a new configuration of current transformer (CT) in transformer differential protection is proposed. In this configuration, only one single phase CT connected in any phase of the delta side is more needed than the traditional scheme. Worked with line currents measured by other current transformers connected in both sides of the transformer, any phase current in the delta side can be calculated based on the Kirchhoff's Current Law. This new scheme ensures the accurate calculation of the equivalent instantaneous inductance, which is immune to the loop current existed in the delta side of transformer, as well as no dead zone in transformer differential protection. A new algorithm based on the distribution of the normalized equivalent instantaneous inductance for the discrimination between inrush current and fault current is proposed. The normalization of equivalent instantaneous inductance makes the setting-value have little relation with the parameter of transformers, which has more universal meaning in the determination of setting values. Utilizing the distributive characteristic of the normalized equivalent instantaneous inductance, the variety of the normalized equivalent instantaneous inductance is effectively revealed. At last, experiment data obtained from HYBRISIM (Hybrid Simulator) validates the reliability and sensitivity of this algorithm. This algorithm has good prospect of engineering application in the EHV transformer protection.

关键词： Transformer protection

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A statistical method of improving the resolution of time-delay of UHF signals for PD location in transformers

A statistical method of improving the resolution of time-del...

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Conference on Electrical Insulation and Dielectric Phenomena, (CEIDP)

作者： Zhiguo Tang Chengrong Li Xu Cheng Wei Wang Jun Li Key Laboratory of Power System Protection and Dynamic Security Monitoring and Control Ministry of Education North China Electric Power University Beijing China

It's important to make an accurate PD location in transformers for fault diagnosis and maintenances of power systems. Theoretically it's possible to locate the PD source by measuring the differences in the arrival time at the UHF sensor array. The propagation velocity of EM wave in air is 30 cm/ns, which is extremely fast, so the resolution of the time-delay of UHF signals detected at the UHF sensor array is one of the key points to make an accurate PD location. Here, we propose a mathematical method: cross-correlation-shifting-averaging algorithm that can improve the resolution of the UHF signal's time-delay by increasing the signal to noise ratio and reducing the time dispersion caused by the random nature of PD. The practical processing results of experimental data from our laboratory indicate that the method can increase the time-delay resolution by nano-seconds in some cases, which improve PD location accuracy by tens of centimeters.

关键词： Statistical analysis Signal resolution Transformers Sensor arrays Microwave antenna arrays Fault diagnosis power system faults power system measurements Time measurement UHF measurements

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The fault diagnosis layer model of electric power grid based on weighted mean roughness

The fault diagnosis layer model of electric power grid based...

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

作者： Li Ran Ix Li Jinghua Key Laboratory of Power System Protection and Dynamic Security Monitoring and Control Ministry of Education China Electric Power University Baoding Hebei China

Based on rough set, this paper use discernibility matrix to reduce the condition attributes. The reduced samples are laid by weighted mean roughness to avoid blindness and redundancy. By this method, model space can be compressed greatly and weighted mean roughness is easy to calculate. Weighted mean roughness is used to separate attributes' priority in every lay, which make the diagnosis system had strong tolerant ability. When the electric power grid is fault, the result of diagnosis will be correct by searching every lay with priority level. The correctness and effectiveness are validated by the analysis result of emulation

关键词： Fault diagnosis power systems Fault tolerance Redundancy Blindness power system modeling Emulation power grids Rough sets power system reliability

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Parallel operation of hybrid active power filter with passive power filter or capacitors

Parallel operation of hybrid active power filter with passiv...

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

作者： Yonghai Xu Xiangning Xiao Hao Liu Hong Wang Key Laboratory of Power System Protection and Dynamic Security Monitoring and Control Ministry of Education North China Electric Power University Beijing China

Harmonic pollution and reactive power compensation are the important power quality problems. This paper proposes a combined power filter system consisting of the parallel operation of a hybrid active power filter (HAPF) and the passive power filters or capacitors. The HAPF is formed by a single tuned LC filter per phase and a small-rated three-phase active filter, which are directly connected in series. The characteristics of the combined system and the harmonic current detection method using the combination of load current and the mains current are analyzed and simulated. The simulation results show that good filter performance can be obtained by the combined system. Experimental results from a 100 kVA/380 V hardware prototype parallel operation with capacitors are presented to conform the validity and effectiveness of the combined system

关键词： Active filters power filters power capacitors power harmonic filters power system harmonics Pollution Reactive power power quality Harmonic analysis Analytical models

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