适用于弱馈系统的零序方向元件防误动方法  

A Novel Method Adapted to Weak-Infeed System for Preventing Mal-Operation of the Zero-Sequence Direction Component

作　　者：徐海洋[1] 宋国兵[1] 樊占峰 刘珮瑶 

机构地区：[1]西安交通大学电气工程学院,陕西省西安市710049 [2]许继集团有限公司,河南省许昌市461000

出　　处：《电网技术》2015年第10期2952-2958,共7页Power System Technology

基　　金：国家重点基础研究发展计划(973计划)(2012CB215105);国家电网公司科技项目(SGTYHT/14-JS-188)~~

摘　　要：线间零序互感作用会引起健全线的零序方向元件误动。分析了健全线和故障线的电流突变量特征,得出了健全线的三相电流突变量相等,而故障线的三相电流突变量相差较大的结论。弱馈系统中,故障线弱馈侧的三相电流突变量近似相等,使得仅利用电流突变量特征的健全线识别方法不再适用。针对此问题,具体分析了弱馈方式下健全线和故障线的故障特征,构造了含电流和电压误差系数的综合误差系数判据。PSCAD仿真结果表明,综合判据在弱馈和非弱馈方式下均能可靠进行线路识别,从而可靠闭锁健全线的零序方向元件和开放故障线的零序方向元件。文中提出的防误动方法仅利用本线的单端电气量,且能够自动识别线路所处的电磁环境,具有一定的实用价值。Mutual inductance between lines would cause mal-operation of the zero-sequence direction component. Differences of fault characteristics in three-phase current fault components between healthy lines and the fault line were analyzed and it was found out that three-phase current fault components of healthy lines are equal, while those of the fault line are quite different. In the weak-infeed operation mode, three-phase current fault components are approximately equal on the weak-infeed side of the fault line. Thus, the identification method using only current fault components is not applicative. To solve this problem, a comprehensive criterion consisting of both current and voltage error coefficients was constructed through analyzing differences of fault characteristics in three-phase current and voltage fault components between healthy lines and the fault line thoroughly under weak-infeed operation condition. PSCAD-based simulation results show that the comprehensive criterion is reliable in identifying healthy lines and the fault line in both weak-in feed and not weak-in feed operation modes. Consequently, zero-sequence direction components of healthy lines can be blocked while those of the fault line are not blocked. In the proposed method using both current and voltage error coefficients, only single-loop and single-ended electrical quantities are needed. In addition, the method is capable of automatically identifying electromagnetic situation of the lines. Thus, it is of practical value.

关 键 词：零序方向元件 零序互感 弱电强磁 弱馈 突变量 

分 类 号：TM77[电气工程—电力系统及自动化]