变压器是电网变换电压和传送电能的电气设备，是电网向用户供电的载体，变压器的安全可靠运行情系万家灯火。然而在电网运行中由于诸多原因会产生过电压，而变压器的绝缘水平相对比较薄弱，在变压器损坏的原因中，过电压造成损坏的概率最大。在电网运行中因某种原因产生过电压，必将导致变压器的损坏，其绝缘水平主要由雷电击耐受电压和工频耐受电压来决定。

Transformer is the power converter voltage and the transfer of power electrical equipment, power grid to vector of user power supply transformer, safe and reliable operation of the lamps and candles of a myriad families. However, in the operation of power grid, there will be over-voltage due to a variety of reasons, and the insulation level of the transformer is relatively weak. In the cause of transformer damage, the overvoltage is the most likely to cause damage. In the power grid operation, the overvoltage is caused by some reasons, and the insulation level is mainly determined by the lightning withstand voltage and the withstand voltage of the power frequency.

过电压系指对绝缘有危险的突然电压升高，这种非正常的电压升高，其幅值可达设备额定电压的几倍以上，严重威胁变压器绝缘的安全，若过电压持续时间较长，必将造成变压器的损坏。为确保电网运行中变压器的安全，除选用优质的变压器外，还要对变压器设置合理有效的过电压保护措施。

Overvoltage refers to a sudden rise in dangerous voltage insulation, the abnormal voltage increase, more than a few times the amplitude can reach the rated voltage of the equipment, a serious threat to the safety of transformer insulation, if the voltage continues for a long time, will cause the damage of transformer. In order to ensure the safety of the transformer in the power grid operation, besides the choice of high quality transformers, a reasonable and effective overvoltage protection measure should be set up for the transformer.