A comprehensive analysis for asymmetrical short-circuit fault of electric power system with neutral-point unground

Authors：王丙东; 蔡蕾; 董旭; 李贺桥; 王浩轩; 刘灿; 张好勇; 王龙宇

Source：电力系统保护与控制, 2017, 45(3).

DOI：10.7667/PSPC160115

• neutral-point unground
• distribution system
• short-circuit
• capacitance
• drift

In order to improve reliability about distr-ibuted generation access into power system,this paper provides an intensive analysis for fault characteristics of neutral-point unground based on method of symmetrical components.It presents the variation feature of voltage and current for single phase to earth,phase to phase short circuit and two-phase grounding together with transition impedance.The result is that phase to phase short circuit of neutral-point unground is the same as neutral-point grounding with neutral-point undrift.However,two-phase grounding is the same as phase to phase short circuit of neutral-point grounding with neutral-point drift.The conclusions could be applied in contingency analysis and protection setting in real distribution system within distributed generation.