500kV自耦变压器中性点经小电抗接地方式在电力系统中的应用

该是《三峡电站５００ｋＶ主变压器中性点接地方式优化选择》一的续篇。随着电力系统不断扩大,受端系统逐步加强,５００ｋＶ变电站特别是２２０ｋＶ侧单相短路电流大于三相短路电流的现象时有发生,给设备选择带来困难。中研究了５００ｋＶ变电站单相短路电流急剧增长的原因,计算论证了经小电抗接地是限制单相短路电流的有效措施之一,并阐述了５００ｋＶ自耦变压器中性点经小电抗接地后,其等值零序电抗的计算方法,可供工

APPLICATION OF AUTOTRANSFORMER NEUTRAL GROUNDING BY SMALL REACTANCE IN 500 kV POWER SYSTEM

This paper is a continuation of the paper titled "Optimal Selection of 500kV Main Transformer Neutral Grounding in Three Gorges Hydroelectric Power Stations". Along with the extension of power system and the enhancement of receiving end capacity, the phenomena that the single phase short circuit current at the 220kV bus in 500kV substation will be larger than three phase short circuit will often occur and it will cause trouble in choosing related devices such as circuit breakers. In this paper the reason of rapid increase of single phase short circuit current in 500kV substation is analyzed. Through the calculation it is proved that neutral grounding by small reactance is an effective measure to reduce the single phase short circuit current, and the calculation method of the zero sequence reactance after autotransformer neutral grounding by small reactance being applied is expounded.