Research on the Checking for Anti-short Circuit Ability of 500kV Power Transformer

As the crucial device of the power grid, the power transformer is important to ensure the safe and reliable operation of the electric system, which will cause great economic loss and damage of the power system once short-circuit fault happen. Based on the investigation and analysis of accident happened in recent year, more than a third of the power system fault relate to short-circuit of transformers. Given the 500kV power grid has become the backbone of the high voltage power transmission network system, as well as the auto-transformers make up a high proportion of 500kV transformers, it is imperative and indispensable to check and improve the anti-short circuit ability of 500kV transformer. In order to know the checking for anti-short circuit ability of 500kV power transformer profoundly, the rapid computational method of transformer short-circuit current under three kinds of short circuit conditions are deduced in paper including three-phase symmetric short-circuit faults, single phase short-circuit faults and two-phase short-circuit faults. Combined with the analysis of winding leakage magnetic field and short-circuit force, Comparison Research on short-circuit impact of 500kV power transformer is carried out. According to the result of analysis, it turns out the anti-short circuit ability of example transformer is insufficient, and need to take relevant measures. Besides, some relevant measures are put forward to enhance the anti-short circuit ability of the on-line transformers to provide the reference for daily maintenance of transformer.