220kV Transformer 10kV Side without Load Surge Arresters Selection Method

Analyzing to operation mode of 10kV side with no load of 220kV main transformer, the shortcoming of the B-phase direct grounding operation type and a arrester parallel connecting with each phase on 10kV side with no load of transformer is the best protecting method are pointed out. Through the demonstration to the generating conditions and calculation of capacitance transfer voltage, the right nominal voltage choosing methods for gapless arrester and the application possibility of gap zinc oxide arrester are presented, and the feasibility and effectiveness are proved by a operation example in this paper.