500kV自耦变中性点串接小电抗对接地短路电流限制效果分析

Analysis of limiting effect of 500kV autotransformer neutral grounding by small reactance on ground short-circuit current

针对华北电网部分220kV母线单相短路电流超过其三相短路电流问题,分析了华北网的网架结构、电网特性和变压器的结构特点,以及220kV单相短路电流急剧增加的原因。根据华北电网2009年冬季大负荷数据,选择在华北电网的安定站、顺义站、滨海站和保北站,运用电力系统分析综合程序软件(PSASP),做主变中性点经小电抗接地的短路电流计算。根据短路电流计算结果,分析了500kV自耦变压器中性点经小电抗接地方式对220kV侧单相短路电流的限制效果,分析了网架结构对小电抗限流作用的影响,给出了小电抗选取的工程指导意见。

Aiming at the issue that part of 220 kV bus single-phase short-circuit current exceeds the three-phase short-current,the network structure,network characteristics and the structural characteristics of transformer in North China Power Grid,and why 220 kV single-phase short-circuit current increases sharply are analyzed.According to the high load data of North China Power Grid in winter of 2009,this paper selects the Anding Station,Shunyi Station,Binhai Station and Baobei Station in the North China Power Grid,and uses the Power System Analysis Software Package（PSASP） to make short-circuit current calculation of main transformer neutral grounding via low resistance.According to short-circuit current calculation,it analyzes the limiting effects of 500 kV autotransformer neutral grounding by small reactance on 220 kV single-phase short-circuit current,the effects of grid structure on limiting the low reactance current,and gives a project guidance about small reactor＇s selection.