一起大型发电机中性点电流互感器故障诊断与分析

Diagnosis and Analysis on a Fault of Neutral Point Current Transformer for Large Generator

通过对某大型水力发电厂一起保护装置报警故障的诊断及分析,明确了由中性点电流互感器损坏导致故障的原因。依据该厂运行经验,提出了对发电机通风系统进行风道测试并进行相应的技术改造,以降低发电机风洞环境温度;在铭牌上按国标要求标注电流互感器的绝缘耐热等级;大型发电机应选用绝缘耐热等级为F级及以上的电流互感器;相邻相间电流互感器应有足够的抗干扰距离等改进措施。

Through the diagnosis and analysis on a failure alarm of protection device in a large hydropower plant, it is clear thai the fault is caused by the damage of neutral point current transformer. According to operation experiences, some improvement measures are proposed, such as conducting air passage test and technical reform of generator＇s ventilation system to reduce wind tunnel ambient temperature of generator, marking the thermal class of current transformer on the label according to national standards, using the current transformer with a thermal Class F or above for large generators, and arranging current transformers of adjacent phase with sufficient anti-interference distance.