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Kang Y.,University of Sichuan | Li H.-Q.,University of Sichuan | Zheng W.,University of Sichuan | Kang N.,Deyang Electrical Power Bureau | Zhao L.,University of Sichuan
Dianli Xitong Baohu yu Kongzhi/Power System Protection and Control | Year: 2011

Based on the mathematical model of static energy function, this paper proposes a new voltage control partitioning method using fuzzy clustering analysis, which is established on the energy/voltage sensitivity matrix. With the energy information of nodes, we establish the energy sensitivity matrix (ESM) based on the tendency index of nodes. Then the ESM is decomposed to get the voltage control area by maximum tree method of fuzzy clustering analysis. It is used in IEEE 30 node system. The partitioning result is analyzed and compared with the other methods to demonstrate the validity and feasibility of the proposed method, and the obtained partitioning result meets the requirement of inter-area strong coupling and regional weak coupling. Source

Ma C.,University of Sichuan | Xiao X.,University of Sichuan | Yuan Z.,Deyang Electrical Power Bureau | Li C.,University of Sichuan
Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering | Year: 2012

The Monte Carlo simulation assessment methods mostly adopt the classical probability measure or fuzzy measure to describe the occurrence possibility of cascading failures in power grids, and they need a large number of samplings to ensure a certain calculation premise. In order to avoid these deficiencies, a new fuzzy simulation assessment method to solve the occurrence possibility of cascading failures was proposed on the basis of credibility theory. Using the hidden failure model as the propagation mechanism of cascading failures, the physical and mathematical essence of cascading failures were analyzed in detail, and the credibility measure was applied to describe their occurrence possibilities. On the simulation analysis of the WSCC 9-bus test system and a western regional power grid, compared with some traditional methods, the results have proved that the proposed method can accurately identify the cascading failures with small possibilities only conditioned upon less sampling calculations, and it is characterized by adaptability, validity and accuracy. © 2012 Chinese Society for Electrical Engineering. Source

Zhijian Y.,Deyang Electrical Power Bureau | Yan L.,Sichuan Electric Power Corporation
Advanced Materials Research | Year: 2012

The impact of voltage sags on equipment is usually described by equipment failure probability. It is generally difficult to assess and predict the probability because of the uncertainty of both the nature of voltage sags and the VTL (VTL) of equipment. By defining the equipment failure event caused by voltage sags as a fuzzy-random event, a fuzzy-random assessment model incorporating those uncertainty is developed. The model is able to convert the probability problem of a fuzzy-random variable to that of a common random variable by using λ-cut set. It is thus valuable in theoretical analysis and engineering application. The validity of the developed model is verified by Monte Carlo stochastic simulation using personal computers (PCs)as test equipment. © (2012) Trans Tech Publications, Switzerland. Source

Hu J.-L.,Chongqing University | Sun C.-X.,Chongqing University | Jiang X.-L.,Chongqing University | Li Y.,Deyang Electrical Power Bureau | Zhang Z.-J.,Chongqing University
Gaodianya Jishu/High Voltage Engineering | Year: 2010

Characteristics of surface DC arc on pre-polluted ice and icicle-icicle air gap DC arc under low air pressure is fundamental to the study on the discharge mechanism and the model of insulators under the combined conditions of high altitude, pollution and icing. We analyzed E-I characteristics of surface DC arc on pre-polluted plane triangular ice sample and icicle-icicle air gap DC arc under low air pressure in the low-temperature and low-pressure climate chamber. The results show that, the E-I curves of surface DC arc and icicle-icicle air gap DC arc are respectively in a negative power function relationship; the voltage of positive surface arc is higher than that of the negative one under the same conditions, while the polar of voltage has little effects on the E-I characteristics of icicle-icicle air gap DC arc; the E-I characteristics of surface DC arc and icicle-icicle air gap DC arc decrease with the decreasing air pressure, and icicle-icicle air gap arc is more remarkably affected by the pressure, compared with surface arc. The results can lay the foundation for the establishment of the DC discharge model of polluted and iced insulator strings under low air pressure. Source

Zhang X.-X.,Chongqing University | Ren J.-B.,Chongqing University | Li Y.,Deyang Electrical Power Bureau | Liao S.-W.,Chongqing University | And 2 more authors.
Gaodianya Jishu/High Voltage Engineering | Year: 2010

SF6 partial discharge can generate stable decomposition components, which can be used to monitor the inner insulation in GIS. We compared the infrared spectrum (IR) by taking the pure SF6 and N2 as background gas and selecting the former for the IR detection background gas, obtained standard spectra and optimum absorption peaks of SOF2, SO2F2, SO2, CO, and calculated the absorption coefficients of the optimum absorption peaks. IR spectra were detected under five different partial discharge magnitudes after calibrating the partial discharge test device. It is found that there is critical partial discharge magnitude, there are different gas production rates with different discharge time and discharge magnitude. SOF2, SO2F2' gas production rates have rules with different discharge magnitude, which can diagnosed partial discharge level in GIS; moreover, the variation of SO2, CO' gas production rates is complex, but the single varying trend can still indicate the inner insulation condition. Source

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