Analysis of 220kV Transformer Tripping Accident Caused by Neutral Point Gap Breakdown
Through the neutral point of the main transformer is breakdown gap under the lightning over-voltage, and the main transformer is tripped by the zero-sequence protection, the discharge dispersion of gap is large is indicated; When 220kV neutral point is ungrounded ,the protection must be sharing after arrester parallel gap is proposed. The two-phase or three-phase wave is the main reason of the protection device action are pointed by discussing the wave process in the transformer; The most simple and effective way is placing special transparent insulating over the gap is proposed.
G. Chen et al., "Analysis of 220kV Transformer Tripping Accident Caused by Neutral Point Gap Breakdown", Applied Mechanics and Materials, Vol. 310, pp. 387-390, 2013