煤矿6(10)kV高压配电装置零序电压取样电路的改进

Improvement of the zero-sequence voltage sampling circuit in coal mine high-voltage distribution device

目前高压电网绝缘监视及选择性漏电保护采用三绕组电压互感器第三辅助绕组组成的零序电压虑序器进行零序电压检测,实质是对电网进行接地的监视和保护,高压绝缘监测器采用直流检测的方法,检测电网绝缘阻值,可以早期发现电网对称和不对称的阻值下降,为此采用绝缘监测器作为电网漏电保护系统的主保护,现行的绝缘监视和选择性保护作为后备保护,对采用零序电压信号进行保护的这些装置,其零序电压由分压式零序电压取样电路供给。

At present,high-voltage power-net insulation monitoring and selective leakage protection are achieved by zero-sequence voltage test with a voltage sequeuce filter which consists of the third split-phase winding of three-winding potential transformer.This monitoring method is in fact a grounded monitoring and protection.High-voltage insulation monitor is able to detect power-net insulation resistance by way of DC testing.Insulation monitor ought to be used as chief protection of power-net leakage protectional system,and insulation monitoring and selective protection as emergency protection.Power-net protectional systems employ zero-sequence voltage,which is provided by capacitance-voltage-division type zero-sequence voltage sampling circuit.