变电站220 kV侧单相短路电流超标问题分析及解决方案

摘要

Jilantai Substation is an important 500 kV substation in Inner Mongolian Grid. 3 main transformers parallel operate, along with several power plant generators puting in operation, single phase short circuit of Jilantai 220 kV bus is 50.2 kA, exceeding the rated capacity of circuit breakers. This problem will seriously threaten the safty of power system.Be aimed at this problem,several methods was discussed to reduce single phase short circuit of Jilantai 220 kV bus, including reduing ground point, installing small neutral reactor on transformer, and spliting operation 220 kV bus, and building the forth transformer. Meanwhile calculated the short circuit of Jilantai 220 kV bus base of above methods. The decreasing amplitude of 2nd method was 6 kA. Through detail analysis, installing small neutral reactor on transformer was the most available method.%吉兰太变电站是内蒙古电网的一座500 kV枢纽变电站，该变电站3台主变压器并列运行，随着新增电源项目的接入，变电站220 kV侧单相短路电流值将达到50.2 kA，超出开关设备的额定遮断容量（50 kA），影响电网的安全稳定运行。针对该问题，提出减少接地点、在主变压器中性点加装小电抗、将主变压器220 kV母线分裂运行及建设第4台主变压器等解决方案，并对采取各方案后吉兰太变电站220 kV侧单相短路电流进行了计算分析，其中，采用在主变压器中性点装设小电抗方法可将短路电流降低约6 kA，建议采用该方案。