China EPRI Science & Technology Co.

Beijing, China

China EPRI Science & Technology Co.

Beijing, China
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Zhang L.,China EPRI Science & Technology Co. | Li B.,Beijing Electric Power Company | Wang S.,China EPRI Science & Technology Co. | Ren X.,Beijing Electric Power Company
Gaoya Dianqi/High Voltage Apparatus | Year: 2016

There is no industrial standard and specification at present for the thyristor valve bank in 10 kV solid-state switch. In this paper, to set up appropriate items, method and parameters of the test for verifying the insulation reliability of the thyristor bank, the characteristics of the thyristor bank are analyzed and calculated, and methods and steps of its high voltage insulation test are discussed according to the standards and engineering experiences of other similar power electronic equipment. In addition, some issues and their treatment are mentioned. This study may provide a basis for the product design. © 2016, Xi'an High Voltage Apparatus Research Institute Co., Ltd. All right reserved.


Ji X.,Shandong University of Science and Technology | Chen H.,Shandong University of Science and Technology | Zi Z.,China EPRI Science & Technology Co. | Ben B.,China EPRI Science & Technology Co.
Dianli Xitong Baohu yu Kongzhi/Power System Protection and Control | Year: 2015

This paper presents a new method which applies low leakage reactance transformer and low voltage shunt active power filter to compensate for the side of high voltage. According to the field condition and the phase-shift characteristic of transformer, the original control strategy is improved by using a new type of digital phase-locked loop technology. The harmonic suppression and reactive power compensation of high voltage bus are realized by low voltage active power filter. Without changing the internal structure of low voltage active power filter, it can accomplish some compensation tasks of high voltage power filter, thereby reducing equipment investment. Due to the low voltage grade of filter, the difficulty of equipment maintenance is reduced, and the safety of the operators is also improved. The PSCAD/EMTDC simulation tool and field test are adopted to verify the effectiveness and feasibility of the proposed approach. © 2015, Power System Protection and Control Press. All right reserved.


Zheng T.,North China Electrical Power University | Zhao Y.,North China Electrical Power University | Jin Y.,North China Electrical Power University | Zhang Z.,China EPRI Science & Technology Co. | And 5 more authors.
Dianli Xitong Zidonghua/Automation of Electric Power Systems | Year: 2014

Based on the engineering application, the excitation system of an extra-high voltage (EHV) magnetic controllable shunt reactor (MCSR) is described and the characteristics of control winding turn-to-turn fault of a MCSR is analyzed. According to numerical simulations and experimental tests, a problem in the application of overvoltage protection against control winding turn-to-turn fault is discovered, that is, such a protection operation is delayed or even a malfunction. This is because the fault features DC buses during a turn-to-turn fault intermittent voltage spikes rather than standard sinusoidal overvoltage and the fault feature may even not exist in some fault cases. The current distribution model for the excitation system during a turn-to-turn fault is built and it is concluded that the appearance of fault features on DC buses depends on the zero-crossing of the total control current. A new protective scheme that uses the fundamental component in the total control current as criterion is proposed and simulation results have verified the effectiveness of the new scheme.


Liao M.,State Grid Corporation of China | Ma X.,China EPRI Science & Technology Co. | Zhou Z.,State Grid Corporation of China | Hu J.,China Electric Power Research Institute
Gaoya Dianqi/High Voltage Apparatus | Year: 2015

A design method of optimal tilt angle of PV array for stand-alone photovoltaic power generation system is proposed. Four PV simulation softwares for tilt angle calculation are introduced. And because of the extraordinary function, PV & SOL is chosen to design the tilt angle of PV arrays in a photovoltaic power generation system in northwestern area. The proposed method of design synthetically takes the irradiation, load requirement, life span of lead-acid battery and some other factors into consideration. Compared with traditional method which merely considers irradiation, the proposed method is far more scientific and practical. ©, 2015, Xi'an High Voltage Apparatus Research Institute. All right reserved.


He Z.,North China Electrical Power University | Zhou Z.,State Grid Corporation of China | Ma X.,China EPRI Science & Technology Co. | Hu J.,China Electric Power Research Institute
Gaoya Dianqi/High Voltage Apparatus | Year: 2015

An estimation method of depth of discharge(DOD) of lead-acid battery in photovoltaic power generation system is proposed. This method calculates irradiation per hour by developing normal distribution model of irradiation per day. Then DOD of battery can be calculated by analyzing both the hourly irradiation and load requirement. This method solves the problem of shortage of hourly climate data in many regions. What is more, this method is introduced in detail by taking the photovoltaic power generation system in Xinjiang as an example. At last, simulation of the same generation system is executed by PV & SOL which verifies the proposed method. ©, 2015, Xi'an High Voltage Apparatus Research Institute. All right reserved.


Yang S.,China EPRI Science & Technology Co. | Xu H.,China EPRI Science & Technology Co. | Song X.,Beijing Institute of Petrochemical Technology | Li X.,China EPRI Science & Technology Co.
Dianwang Jishu/Power System Technology | Year: 2015

The obvious voltage drop at the receiving end of long-distance radial distribution line with heavy load affects the voltage quality of power supply, and both serial and shunt reactive power compensation are the measure to solve this problem. The compensation effect from the serial compensator and the shunt compensator may be cancelled out each other while they are put into operation simultaneously, so it is necessary to research the compatibility between both compensators. Taking the curve of voltage at load point varied with series compensation degree as the analysis tool, firstly, the radial distribution line with only load at its end is analyzed and the compatibility rule between serial compensator and shunt compensator is achieved; further, through the simulation of a certain 66kV distribution network it is proved that the above-achieved compatibility rule is also suitable for distribution lines with multi load points; besides, two coordination modes of series compensation with shunt compensation, namely the over-compensation of series capacitor with shunt reactor and the series reactor with over-compensation of shunt capacitor, are derived, by which the voltage at the receiving end can be evidently improved. ©, 2015, Power System Technology Press. All right reserved.


Chen X.,China EPRI Science & Technology Co. | Chen X.,China Electric Power Research Institute | Wang Y.,China EPRI Science & Technology Co. | Chen L.,China EPRI Science & Technology Co. | And 3 more authors.
Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering | Year: 2015

Two methods, fundamental component balance and optimization one (FCBO) and volt-second balance and optimization one (VSBO), were proposed to calculate initial values of harmonic elimination equation (HEE) of inverter. Both of the methods divide one cycle (2π) of reference sine s(θ)=Usinθ into Np sub-zones {sn(θ)} with equal phase-gap θ0=2π/Np. Replace sn(θ) by the nth pulse pn(θ) of PWM with height Up, falling edge θ=nθ0, and rising edge in pending. Balancing fundamental components or volt-second products of sn(θ) and pn(θ) were used to set the rising edge of pn(θ) for FCBO or VSBO. From the test results of FCBO and VSBO, two universal methods, modified FCBO (MFCBO) and modified VSBO (MVSBO), were developed. MVSBO just needs one initial value to get real-time accurate solutions of HEE for a given Np with different amplitude modulated index ma. So does MFCBO. Based on a lot of real-time accurate solutions some problems in question about HEE were discussed, such as allowable difference between initial values and accurate solutions, crucial factor for exactly solving HEE, uniqueness of accurate solutions, and solvable zones. Excellent error tolerance and low practical harmonic elimination error of proposed methods were verified by experiments. harmonic elimination equation; fundamental component balance and optimization one (FCBO) method; volt-second © 2015 Chin. Soc. for Elec. Eng.


Zhang S.,China EPRI Science & Technology Co. | Li L.,China EPRI Science & Technology Co. | Zhao G.,China EPRI Science & Technology Co. | Yuan H.,China EPRI Science & Technology Co. | Cui D.,China EPRI Science & Technology Co.
Dianli Xitong Zidonghua/Automation of Electric Power Systems | Year: 2016

The structure of thyristor controlled transformer (TCT) type controllable shunt reactor is analyzed and its operating characteristics are summarized. According to the characteristic of the TCT type controllable shunt reactor that can adjust the capacity smoothly from 90° to 180°, the effect of voltage energy-gaining and current energy-gaining on its operating characteristics is emphasized, and the hybrid voltage-current energy-gaining method is proposed for application in the TCT type controllable shunt reactors. The reliability and feasibility of the hybrid voltage-current energy-gaining method is demonstrated through the establishment of a real dynamic simulation model to provide a design foundation for the TCT type controllable shunt reactors. © 2016 Automation of Electric Power Systems Press.

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