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Liu W.,North China Electrical Power University | Liu Y.,North China Electrical Power University | Liu Y.,Dongfang Electronics Information Industry Co. | Wang Y.,Hangzhou Power Supply Bureau | Li J.,Dongfang Electronics Information Industry Co.
Dianli Xitong Zidonghua/Automation of Electric Power Systems | Year: 2013

Common semantic model is the key to solve seamlessly combine IEC 61970 and IEC 61850 standards. However, there are two issues needed to be addressed in application practice: 1) how to improve the model mapping, expression, and automatic maintenance ability; 2) how to enhance its expansion capability for power business modeling. By introducing the ontology defined meta-model (ODM), according to the thought of model driven architecture (MDA), a complete power system modeling framework is developed based on the EPRI common semantic model. This framework covers various aspects of power grid modeling from the construction of visual modeling environment to the final power business modeling. The key technologies are deeply studied combined with specific examples, including meta-model visualization structure, OWL-based business modeling method, mapping engine design as well as the constraint and reasoning mechanism etc. Practice shows that this framework can not only improve the flexible and clear expression ability for power common semantic model, but also can expand ability from a static modeling to specific domain business modeling. © 2013 State Grid Electric Power Research Institute Press.

Wang K.,Chongqing University | Wang K.,China Electric Power Research Institute | Liao R.,Chongqing University | Zheng S.,Hangzhou Power Supply Bureau | And 3 more authors.
Gaodianya Jishu/High Voltage Engineering | Year: 2013

We performed experiments of partial discharge (PD) induced degradation of oil-impregnated paper in laboratory to investigate the electrical degradation process of oil-impregnated paper caused by PD. Using practical winding insulation papers of transformer as the test object, we obtained the average breakdown time by accelerated electrical degradation experiments to fit the inverse-power-law life model of electrical degradation. Then three testing voltages were determined according to the life model. The electrical degradation process was divided into ten stages, and the PD signals were collected by an ultra-high-frequency antenna throughout the stages. By using the chaos theory, the variation laws of several characteristic features of PD amplitude series, such as the largest Lyapunov exponential, correlation dimension, and Komogorov entropy, were analyzed along with the processing electrical degradation of oil-impregnated paper. It is illustrated that the largest Lyapunov exponent increases with degradation, which is obviously correlated to the degradation condition of oil-impregnated paper. In addition, the correlation dimension shows a certain fluctuation, and it decreases sharply at the pre-breakdown stage. Moreover, the PD chaotic characteristic is the strongest at the initial stage of degradation, rapidly falls into its minimum at the middle stage of degradation, and then increases steadily and slow.

Chen Q.-Y.,Hangzhou Power Supply Bureau | Ren H.,Hangzhou Power Supply Bureau | Luo P.,Hangzhou Dianzi University | Wang J.-Q.,Hangzhou Power Supply Bureau
Gaoya Dianqi/High Voltage Apparatus | Year: 2011

To improve the diagnosis accuracy of winding deformation in power transformer, the integration of frequency response analysis (FRA) method, short-circuit impedance and winding capacitance measurement were discussed and used for identification of transformer windings. The accuracy of dynamic integration of three methods is proved through the comparison of the theoretical analysis and calculation with the disassemble results of the fault power transformer.

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