江西电网变压器短路电流分析研究

Research on transformer short-circuit current in Jiangxi Power Grid

分析了目前江西电网110kV及以上电压等级变压器的短路电流,得出220kV变压器110kV侧短路时流经绕组的短路电流相对较大,且对于三相三绕组变压器单相短路电流大于三相短路电流;在此基础上针对江西电网220kV变压器短路损坏均由110kV侧短路故障引起的特点,计算了2006及2009年系统最大运行方式下,220kV变压器110kV侧短路时流经变压器绕组的电流,论证了电磁环网解环对降低220kV变压器中压侧短路电流作用不明显。

The short-circuit currents of transformers with 110 kV and higher voltage class in Jiangxi Power Grid are analyzed. According to the analysis, the following conclusions are derived： 1） the short-circuit current through the windings is relatively large when the short-circuit faults occurs at the 110 kV side of 220 kV transformer. 2） the single- phase short-circuit current is larger than the three-phase short-circuit currents for the three-phase and three-winding transformer. Based on the analysis above and the fact that the transformer＇s damages are all caused by the short-circuit faults of the 110 kV side in Jiangxi Power Grid, the short-circuit currents through the windings when the short-circuit faults occurs at the 110 kV sides of 220 kV transformers are calculated under system maximum operation mode. Meanwhile, it is proved that there is less effect for breaking the electromagnetically coupled power loop to reduce the short-circuit current of 220 kV transformers.