220 kV变压器中性点接地方式对零序电压的影响  

Impact of 220 kV Transformer Neutral Point Grounding Modes on Zero Sequence Voltage

作　　者：李爽[1] 田庆阳[2] 李鹏里 金鑫[1] 

机构地区：[1]国网辽宁省电力有限公司电力科学研究院,辽宁沈阳110006 [2]国网辽宁省电力有限公司,辽宁沈阳110006

出　　处：《东北电力技术》2014年第3期31-33,48,共4页Northeast Electric Power Technology

摘　　要：为分析在变压器高压侧出口发生单相短路条件下变压器运行方式对系统中性点零序电压的影响,利用对称分量法和序网络法建立了系统的三序网络模型,针对2台变压器低压侧并列运行和分列运行两种情况,研究了系统负荷对零序电压的影响,通过实例验证了分析的有效性。研究表明,系统零序电压与变压器运行方式和负荷综合作用有关。To analysis the affection dergree of transfomrer operation modes on zero sequence voltage on condition of single phase short cirucuit at the high viltage terminal of the transformer,a three sequence networks model is established by means of sysmmetrical component method and sequence networks. The impact of load on zero sequence voltage is researched based on operation modes of the two transformers whose low voltage terminals are connected in parallel and independent,the validity is verified through an example. The results demonstrate that the zero sequence voltage is relative to the operation modes of the transformer and load. The zero sequence voltage when operating in parallel is equal to that of operating independent and the sequence networks are equivalent if the two loads are the same,otherwise,zero sequence voltage when operating independent is little higher than that of operating in parallel. Besides that, there is an excellent suppression effect on zero sequence voltage if the neutral point of the transformer is grounded directly,the zero sequence voltage is the highest if neutral point ungrounded which would likely have a damage to the insulation of netural point,the neutral point connected with a small reactance can also restrain the amplitude of the zero sequence voltage.

关 键 词：零序电压 并列运行 分列运行 单相短路 中性点不接地 序网络 

分 类 号：TM862[电气工程—高电压与绝缘技术] TM406