Study on Necessity of Overvoltage Protection for Secondary Winding Neutral-point of Voltage Transformer: Test and Numerical Analysis on Lightning Transmission Overvoltage at Secondary Winding Neutral-point

In view of the multiple protection misoperation accidents caused by incorrect breakdown of discharge gap at the secondary winding neutral-point of voltage transformer in Guangdong power grid in recent years,test and theoretical study are made on the necessity of installing overvoltage protection for the secondary winding neutral-point of voltage transformer.Experiments and numerical simulations are carried out to study the lightning transfer overvoltage in the neutral-point of the secondary winding under the situation of lightning invasion.The overvoltage level of lightning transmission at the neutral-point of the secondary winding is determined,and the necessity of the overvoltage protection for the secondary winding neutral-point of voltage transformer is confirmed.