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Xicheng, China

Zhang N.,Tsinghua University | Kang C.,Tsinghua University | Xia Q.,Tsinghua University | Liang J.,Jibei Grid Co.
IEEE Transactions on Power Systems | Year: 2014

The integration of wind power requires additional operating reserves to cope with the uncertainty in power system operation. Previous research shows that the uncertainty of the wind power forecast varies with the level of its output. Therefore, allocating reserves dynamically according to the specific distribution of the wind power forecast would benefit system scheduling. This paper presents a statistical model to formulate the conditional distribution of forecast error for multiple wind farms using copula theory. The proposed model is tested using a set of synchronous data of wind power and its day-ahead forecast. It is then utilized in a stochastic unit commitment model to simulate the day-ahead and real-time scheduling of the modified IEEE RTS-79 system integrating wind power. The results show that scheduling reserves dynamically according to the modeled conditional forecast error reduces the probability of reserve deficiency while maintaining the same level of operating costs. © 2013 IEEE. Source


Kang C.,Tsinghua University | Jia W.,Jibei Grid Co. | Xu Q.,Tsinghua University | Liang J.,Jibei Grid Co. | And 2 more authors.
Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering | Year: 2013

As a kind of intermittent power source, wind power makes power systems be confronted with challenges on operation security and stability. The power grid has potential to guide the accommodation of wind power in a wider geographical region, especially in real-time dispatch. The thesis considered constraints of branch power flow and node voltage, took into accounts capability of wind power accommodation (CWPA) of the system and nodes, analyzed the relation among the CWPAs of different nodes, and supported real-time dispatch. An evaluation method of CWPA in real-time dispatch considering security constraints of power grid was proposed, which aims at a certain period in real-time dispatch and evaluates CWPAs of the system and different nodes. Example analysis of IEEE 39-bus test system verified the effectiveness of the proposed evaluation method. Source


Li D.,China Electric Power Research Institute | Xu D.,China Electric Power Research Institute | Sun Y.,Jibei Grid Co. | Cui H.,China Electric Power Research Institute
Gaoya Dianqi/High Voltage Apparatus | Year: 2015

The opening/closing coil is a key component of high voltage circuit breaker s operating mechanism. The authors analyze the relationship between the current waveform of breaker opening/closing coil and the mechanical defects, extract the key characteristics of the coil current waveform, and hence establish a diagnosis criterion for typical mechanical defects of circuit breaker. This diagnosis method is verified on a simulation test platform in laboratory. Further, the coil current test method of circuit breaker for first opening/closing operation is put forward. ©, 2015, Xi'an High Voltage Apparatus Research Institute. All right reserved. Source

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