摘要
继电保护的隐性故障对电力系统安全稳定运行具有重要影响。研究了在电压回路中性线断线情况下,零序方向保护将无法正确判断故障方向,从而造成超高压输电线路的零序方向纵联保护发生误动或拒动,可能进一步导致相关连锁故障的发生。针对电压互感器二次回路中的中性线断线的隐性故障,分析了此时电网正常运行时保护装置的测量电压特征,提出了基于零序电压三次谐波的电压回路中性线断线的识别方法。大量仿真实验结果证明了理论分析的正确性。
Hidden failures in a relay play a key role in the process that lead to power system instability. The paper demonstrated that zero-sequence directional protection could not correctly discriminate the fault direction when the neutral line of voltage circuits was broken. Therefore, in case that the neutral line of a voltage transformer （VT） is broken, it will lead to maloperation of the zero-sequence direction pilot protection and corresponding cascading failures. Secondly, In order to solve the problem , the paper analyzed the characteristics of measured voltages from a VT with a broken neutral line, and proposed the method of identifying the broken state of a neutral line based on the third harmonic of zero-sequence voltages. Simulation results proved the correctness of the theoretical analysis.
出处
《中国电机工程学报》
EI
CSCD
北大核心
2013年第13期179-186,共8页
Proceedings of the CSEE
基金
国家电网公司大电网重大专项资助项目课题(SGCC-MPLG028-2012)
国家自然科学基金项目(50977061)~~
关键词
电力系统
继电保护
隐性故障
电压互感器
零序方向纵联保护
三次谐波
power systems
relay protection
hiddenfailure
voltage transformer （VT）
zero-sequence directionalpilot protection
third harmonic
