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Niu R.,Shandong University | Liang J.,Shandong University | Zhang F.,Shandong University | Zhang X.,Shandong University | Yang X.,Binzhou Power Supply Company
Dianli Xitong Baohu yu Kongzhi/Power System Protection and Control | Year: 2014

A single-ended fault location algorithm is proposed, based on the improved distributed-parameter method and variable time windows of traveling wave. According to the online estimation of the opposite terminal source impedance, the improved distributed-parameter method can be built, to enhance the location-error distribution regularity and improve the feasibility of the assembled fault location algorithm. Then based on the study of the location-error distribution of the proposed improved distributed-parameter method, the variable fault distance window can be computed, determining the variable time windows of the reflected waves to be identified. At last, considering the wiring schemes of local and opposite buses combined with the impact of the interference waves from adjacent buses, reflected waves contained in the variable time windows can be identified and the exact fault location can be detected. Simulation results demonstrate the high reliability and accuracy as well as the engineering application value of the proposed algorithm. ©, 2014, Power System Protection and Control Press. All right reserved.

Cong W.,Shandong University | Sun Y.,Shandong University | Liu G.,Binzhou Power Supply Company | Liu X.,Binzhou Power Supply Company | Wang H.,Shandong University
Dianwang Jishu/Power System Technology | Year: 2013

Based on the basic principle of fixed-frequency signal injection and combining with its practical application, three kinds of schemes are proposed to inject fixed-frequency signal at the secondary side of arc suppression coil (ASC), at secondary winding of bus-bar potential transformer and at the neutral of shunt capacitor bank. The working principles of the three proposed injection schemes are analyzed in detail and the fixed-frequency signal injection based expression to calculate equivalent grounding distributed capacitance of distribution network is derived. From the viewpoint of actual application the detection of the injected signal is discussed, and filtering implementation scheme is designed. Results of lab simulation and field measurement show that using the proposed method the equivalent grounding distributed capacitance of distribution network can be calculated accurately, thus the feasibility of implementing fixed-frequency signal injection schemes is validated.

Li X.-W.,Shandong Electric Power Research Institute | Wang Q.-Y.,Shandong Electric Power Research Institute | Mao H.-Q.,Binzhou Power Supply Company | Li X.-G.,Binzhou Power Supply Company
Gaoya Dianqi/High Voltage Apparatus | Year: 2012

An insulation fault of a running GIS is analyzed by inspecting its appearance and inside, and by measuring the related data. It is found that the quality defect in the insulating rod of disconnector results in the fault of GIS. Some suggestions about reliable online monitoring of GIS state and reasonable design of GIS's major connection and operation modes are offered to ensure safe and stable operation of GIS and reduce loss after fault.

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