三相组合式过电压保护器预试不合格分析

Analysis on Unqualified Preventive Test of Three-phase Combined Overvoltage Protector

三相组合式过电压保护器用于限制相—相、相—地大气过电压和操作过电压,广泛应用于35 kV及以下电力系统中。某燃机发电厂6 kV厂用系统采用带串联间隙的三相组合式过电压保护器,在运行近7年后出现绝缘明显下降的共性问题。通过对不合格过电压保护器的试验及解体检查,分析其绝缘异常的原因并提出了防范措施。

Three-phase combined overvoltage protector is used to limit phase-phase, phase-ground atmospheric overvoltage and operating overvoltage, widely used in power systems 35 kV and below. The 6 kV plant system of a gas turbine power plant adopts three-phase combined overvoltage protector with series clearance.After nearly 7 years of operation, the common problems of insulation decline and power frequency discharge voltage decrease significantly. Based on the tests and the dismantle checks of unqualified over-voltage protector,the reasons of abnormal insulation are analyzed and the corresponding preventive measures are put forward.