SF_(6)气体密度继电器缺陷分析

Defect Analysis on a SF_(6) Gas Density Relay

某500 kV变电站500 kV断路器在本体三相不一致保护回路优化完成后,采用电位测试法验证是否存在寄生回路时发现存在异常电压,检查发现SF_(6)气体密度继电器内部接点之间绝缘电阻降低导致两套直流发生互窜现象。为避免SF_(6)气体密度继电器绝缘电阻降低导致直流接地故障,提出了相应的防范措施。

After the optimization of the three-phase inconsistency protection circuit of a 500 kV circuit breaker in a 500 kV substation,the potential test method is used to verify whether an abnormal voltage exists,during which a voltage anomaly is detected.The inspection reveals that the insulation resistance between the internal contacts of the SF_(6) gas density relays decreases,which causes the occurrence of interchange in the two sets of DC circuits.In order to avoid a DC grounding fault caused by the reduction of insulation resistance of the SF_(6) gas density relay,corresponding preventive measures are proposed.