避雷器是保护雷电过电压的，避免器件遭受雷击瞬时高压的损坏，这种过电压波形前端很陡，频率很高，但后续电流很小，避雷器可以将雷电波的峰值泄放从而保证其后面的电器安全 。通常避雷器正常情况下是处于断路，在经过雷击高压时导通将其释放到大地上。避雷器不负责引雷，如果雷电击中输电线路，雷电过电压会随着输电线路流向变压器或者流过配电装置时，此时避雷器泄流，防止配电装置被击坏。
The lightning arrester is to protect the lightning overvoltage, and avoid the breakdown of the device being subjected to lightning transient high voltage. The overvoltage waveform is very steep at the front end, and the frequency is very high, but the following current is very small. The lightning arrester can release the peak value of the lightning wave, so as to ensure the electrical safety behind it. Normally, the arrester is in the normal condition of a circuit breaker, which is released to the earth when the lightning strikes high. The lightning arrester is not responsible for the lightning. If the lightning hits the transmission line, the lightning overvoltage will flow along with the transmission line to the transformer or flow through the distribution device, so that the lightning arrester will discharge, so as to prevent the distribution device from being damaged.