基于故障分量正序、负序和零序综合阻抗的线路纵联保护新原理

提出了故障分量正序综合阻抗、负序综合阻抗和零序综合阻抗的概念。发生区外故障时,故障分量正序综合阻抗等于线路正序容抗,负序综合阻抗等于线路负序容抗,零序综合阻抗等于线路零序容抗,数值较大;被保护线路上发生区内故障时,故障分量正序综合阻抗、负序综合阻抗和零序综合阻抗分别反映系统和线路的正序、负序和零序阻抗,数值较小。根据该特征,可以区分线路上是否发生故障,据此提出了基于故障分量正序综合阻抗、负序综合阻抗和零序综合阻抗的纵联线路保护原理,不需对电容电流进行补偿,灵敏度高,不受过渡电阻的影响,整定原则明确,定值裕度大。

Principle of pilot line protection based on integrated impedance of fault component

The concept of integrated impedance is proposed for the positive,negative and zero sequences of fault component.When the out-zone fault occurs,the fault component positive sequence integrated impedance is equal to the line positive sequence capacitive impedance,the fault component negative sequence integrated impedance is equal to the line negative sequence capacitive impedance,and the fault component zero sequence integrated impedance is equal to the line zero sequence capacitive impedance,the value is larger.When the in-zone fault occurs,the fault component integrated impedances of the positive,negative and zero sequences reflect respectively the system and line impedances of positive,negative and zero sequences,its value is relatively smaller.The principle of line pilot protection based on the fault component integrated impedances is thus proposed,which does not need the capacitive current compensation nor influenced by the transition impedance,and has high sensitivity,clear setting rules and big setting margins.