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Shan X.,NARI Group | Zhao J.,Suzhou Power Supply Company | Zhang J.,NARI Group | Li W.,East China Gird Co. | And 2 more authors.
Dianli Xitong Zidonghua/Automation of Electric Power Systems | Year: 2012

An on-line integrated fault diagnosis method of power grid based on three-state (steady, dynamic and transient state)data is proposed. Firstly, proceeding from the data characteristic and the status quo of dispatch automation, an analysis is made of the necessity of on-line fault diagnosis using the three state data. Secondly, starting from the aspects of accuracy, real-time, comprehensiveness of on-line fault diagnosis, a technology of data mining and co-processing based on multi-source information is proposed. Lastly, a look-ahead of the future developing direction in the field of on-line fault diagnosis is given. © State Grid Electric Power Research Institute Press.

Xu Y.-Z.,Northeast Dianli University | Sun R.-L.,Northeast Dianli University | Pan W.-M.,Suzhou Power Supply Company
Dianli Xitong Baohu yu Kongzhi/Power System Protection and Control | Year: 2010

Aiming at one severe problem optic current transducer (OCT) faced, temperature excursion that baffles its utility in power system, this paper presents a new method of designing OCT through combining optical fiber sensing and magnetostrictive materials. Pasting the two arms of interferometer on the two surfaces of square magnetostrictive material respectively and ensuring that the optical fiber is pasted uniformly, and the same turns optical fiber is pasted on the two surfaces, which constitutes a symmetrical type of arms M-Z interferometer. This makes fiber-optic current sensor based on the magnetostrictive material have temperature compensation. It can weaken the effects of thermal expansion of the magnetostrictive material. In the experiment, the measurement error of sensing head is 0.65%. It shows that the structure can achieve the effect of temperature compensation to some extent, so that it can meet the demands of the development of modern power system.

Yu J.-Y.,Hohai University | Yu J.-Y.,Suzhou Power Supply Company | Yuan Y.,Hohai University | Zhou J.-H.,Hohai University | Zhang B.,Guohua Dongtai Wind Farm
Dianli Xitong Baohu yu Kongzhi/Power System Protection and Control | Year: 2011

In China, distance protection is installed in output transmission line of wind farm, but system operation parameters will affect protection operating characteristics because of transition resistance. The paper summarizes the research on impact of wind farms on protection, analyzes the short-circuit characteristics of DFIG and introduces the protection configuration of wind farm. A power system short-circuit calculation software considering power flow and transition resistance is developed using VC++. The system example including Dongtai wind farm demonstrates: if transition resistance is constant, when active power or power factor increases, the measured reactance decreases, and may even be negative; there are different effects on measured impedance for different fault types when number of DFIG changes; wind farm operation parameters have almost no effect on the protection when fault component relay is used.

Huang X.,Nanjing University of Science and Technology | Chen J.-C.,Nanjing University of Science and Technology | Wen Y.-X.,Suzhou Power Supply Company | Xiao M.,China Communications Construction Company Ltd.
Dianli Xitong Baohu yu Kongzhi/Power System Protection and Control | Year: 2011

In order to enhance the reliability of STATCOM devices, reduce the influence of the voltage of DC-side on the output, the novel Z-source STATCOM is proposed based on Z-source inverter technology. The new Z-source STATCOM is formed by adding the Z-source network at the DC input side of traditional STATCOM device. It overcomes the shortcoming of traditional STATCOM devices that are vulnerable to the voltage of DC-side, increases the choice flexibility of the power at DC-side of STATCOM device, and improves the reliability. Simplorer 7.05 software is used as a tool of simulation. The result of the comparison between the Z-source STATCOM and traditional STATCOM shows that Z source STATCOM is stable and reliable when the DC-side voltage is unstable.

Zhang S.,North China Electrical Power University | Li P.,North China Electrical Power University | Chen C.,North China Electrical Power University | Shi R.,Suzhou Power Supply Company
Dianli Zidonghua Shebei/Electric Power Automation Equipment | Year: 2013

The variable space narrowing coefficient and the "secondary search" adjustment coefficient of the mutative scale chaotic optimization algorithm are studied, and their determining formulas are proposed. Along with the increase of "secondary search" number and the decrease of variables search space, the variable space narrowing coefficient and the "secondary search" adjustment coefficient decrease continuously to ensure the accuracy of optimization result. Numerical simulation and instance validation verify that, the proposed optimization algorithm is correct and effective. This algorithm is applied to the economic operation of micro-sources in microgrid and their outputs under different objective functions are analyzed.

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