某主变压器故障跳闸原因分析及改进措施

Cause Analysis and Improvement Measures of a Main Transformer Tripping

针对网内发生的一起主变压器故障,对主变及套管的故障情况及同型号设备的排查情况进行分析,同时对故障变压器进行解体检查,确定故障原因为高压套管头部密封不良导致水分进入主变内部,进而引起调压线圈出头引线绝缘裕度下降放电。为了消除此类设备隐患,结合套管结构研制了改进型的密封结构,并提出了有效的运维措施,以避免类似故障再次发生。

Aimed at a main transformer fault that occurred in the power grid,the fault situation of the main transformer and the bushing and the troubleshooting of the same type of equipment are analyzed and the transformer was disassembled and checked.It is determined that the cause of the fault is the poor sealing of the high-voltage bushing head,which caused moisture to enter the main transformer,and then the moisture caused the decreasing of the insulation margin of the outlet lead of the voltage regulation coil and the discharging of it.In order to eliminate the hidden dangers of such equipment,an improved sealing structure was developed in combination with the bushing structure.Effective operation and maintenance measures are proposed to avoid similar failures from happening again.