一起110 kV CVT内部故障引起母线电压异常分析及处理

针对某发电厂110 k VⅠ段和Ⅱ段母线电压偏差异常,通过分散控制系统(DCS)数据调阅、带电检查、理论计算和停电试验等方法综合分析,认为母线电容式电压互感器(CVT)内的部分电容单元存在击穿短路是引起该次母线电压显示异常的原因。返厂解体检查验证了前期分析结果,同时查明该批次电容单元介质薄膜存在绝缘薄弱点和浸油性不好等质量缺陷。据此,要求制造商对该型号批次的产品全部进行了更换,并提出了同类设备的预防措施及处理建议。

Analysis and Treatment of Abnormal Bus Voltage Caused by Internal Faultof 110 kV Capacitor Voltage Transformer

According to the abnormal voltage deviation of 110 kV section I and II bus in a power plant,the DCS system data,on-line examination,theoretical calculation and electrical test are comprehensive analyzed in this paper.Thinking that the 110 kV bus voltage anomaly is caused by some internal capacitor unit short circuit in the CVT.Then return the equipment to the factory,the result of the preliminary analysis is verified by the disassembly inspection,at the same time some capacitor unit quality defects are founded out,such as insulation material weakness and bad dipping property.Accordingly,require the manufacturer to replace all the products of this batch,then propose some treatment measures and suggestions for the same type equipment.