The varistor connected in series to the gas discharge pipe can slightly reduce the value of v1ma without affecting the pressure-sensitive level of the protection. On the one hand, the gas discharge tube can block the leakage current in the varistor during the normal system operation and slow down the deterioration of the performance of the varistor; On the other hand, the advantages of fast pressure-sensitive response, good nonlinearity and large current capacity are used to protect the electrical equipment in time, eliminate the following current problems during the discharge of the gas discharge tube, and effectively damp the sensitivity and difficulty of the lightning wave with high steep wave head. This paper introduces a surge protection scheme for power supply of varistor and GDT:

1,1, application background

1. Global warming and severe rainstorm

2. After the lightning power is damaged, the damage is large

3. The maintenance cost is high after the lightning power is damaged

4. High voltage surge protection device has become an industry trend

2、 Protection scheme and shuokai devices