某330kV变压器空载充电接地故障继电保护动作分析

Analysis of relay protection action of grounding fault of no-load charging of a 330 kV transformer

针对某330kV启备变压器空载充电时发生继电保护动作的问题,通过分析电量分析仪记录的充电电流波形,指出该继电保护动作是由A相电流互感器接地故障引起,并给出了提高大型变压器充电试验安全可靠性的几点建议:加强对变压器高压侧电流、电压互感器的绝缘检查;适当提高变压器主、后备保护的灵敏度,防止励磁涌流造成继电保护动作;充电过程中应对变压器高压侧三相电压、电流进行录波。

In view of problem that a 330 kV start-up standby transformer took place relay protection action in no-load charging, the paper indicated that the action was caused by grounding fault of A-phase current transformer through analyzing charging current waveform recorded by electric quantity analyzer, and gave several suggestions to improve safety and reliability of charging test of large-scale transformer： strengthen insulation inspection for current and voltage transformers of high-voltage side of transformer; properly increase sensitivity of main and backup protection to prevent relay protection action by inrush current; it should record for three-phase current and voltage of high-voltage side of transformer in charging process.