主变套管零序TA接线故障分析

Fault Analysis of Zero-Sequence TA Wiring for Main Transformer Bushing

分析了某地区一起110 kV线路故障导致主变高压侧间隙过流保护动作三侧开关跳闸的事故。通过调阅主变高、中压侧故障录波波形以及对系统零序网络分析,发现主变高、中压侧零序套管TA接反导致线路接地故障,主变高压侧间隙过流保护感受到零序电流从而越级动作,并针对该起事故暴露出的问题,提出了具有针对性的整改措施和建议。

This paper analyses a tripping accident of three-side switch caused by a 110 kV line fault in a certain area,which resulted in clearance overcurrent protection action of the high voltage side of the main transformer.Through reading the fault recording waveforms of the high and medium voltage side of the main transformer and analyzing the zero sequence network of the system,it is found that the TA reversed wiring of the zero sequence casing on the high and medium voltage side of the main transformer led to the grounding fault of the line,which makes the gap overcurrent protection of the high voltage side of the main transformer feel the zero sequence current and thus overstep the operation,and puts forward the targeted rectification measures and suggestions in view of the problems exposed in the accident.