应用500 kV高阻抗主变压器提高220 kV片区供电能力

针对片区220 kV电网的3种典型结构模式研究了片区500 kV站主变压器阻抗选择对片区供电能力的影响。经研究发现:提高500 kV变电站主变阻抗对提高220 kV片区供电能力有显著效果，新建500 kV站应尽可能提高其高 — 中侧阻抗，结合目前工程实践和设备制造厂商的技术水平，其阻抗百分比取20%较为适宜。

Improving Power Supply Capability of 220 kV District Grid Using 500 kV Main Transformer with High Short Circuit Impedance

There are three typical structure modes in 220 kV district grid. The impact of the short circuit impedance of a 500 kV main transformer on the power supply capability of the three types of 220 kV district grids is studied. The results show that the power supply capability of a 220 kV district grid can be effectively improved by increasing the short circuit impedance of the 500 kV main transformer. So it is recommended that a new 500 kV transformer substation should be equipped with transformers with high impedance at its high-and middle-voltage sides. According to the practice and current technical level of the equipment manufacturers, 20% is a feasible impedance percentage.