摘要
提出了一种基于三序差动电流相近原理的零序电流差动选相元件,利用相量图分析了输电线路接地故障时各相三序差动电流的电气特征。分析表明,单相接地故障时故障相三序差动电流大小相等、方向相同。根据该特征,通过比较三序差动电流识别单相接地故障相,选相判据中选取零序差动电流作为极化量,自适应调整选相判据的动作区,保证两相接地故障时选相判据不动作。利用RTDS进行了仿真验证,仿真结果与理论分析一致,该选相元件灵敏度高,不受负荷电流的影响,能够准确识别单相接地故障相。
A zero-sequence current differential phase selection element based on a three-sequence differential currents similar principle is proposed. The electric characteristics of three-sequence differential currents in different grounding faults of transmission line are analyzed with phasor diagram. For single-phase-to-ground fault, magnitude and direction of three- sequence differential currents of fault phase are the same, and according to this, three-sequence differential currents are compared to identify phase of single-phase-to-ground fault. And zero-sequence differential current in phase selection criterion （PSC） is selected as polarization quantity. Then acting area of PSC is adaptively adjusted, in order to ensure that PSC will not act when two-phase-to-ground fault happens. Real time digital system （RTDS） simulation results show that it is same as theory analysis, and the sensitivity of phase selection element is high. The phase selection element is immune to load current and is able to correctly identify fault phase of single-phase-to-ground.
出处
《电力系统自动化》
EI
CSCD
北大核心
2013年第16期92-95,共4页
Automation of Electric Power Systems
关键词
零序电流差动保护
选相元件
单相接地
灵敏度
安全性
zero-sequence current differential protection
phase selection element
single-phase-to-ground
sensitivity
security
