电网技术2011，Vol.35Issue(3)：152-158,7.
110kV变压器中性点过电压的计算及其保护策略
Calculation of Overvoltage on Neutral Point of 110kV Power Transformers and Corresponding Protection Strategy
于化鹏 1陈水明 1余宏桥 1杨鹏程 1印华 2吴高林2
作者信息
- 1. 电力系统及发电设备控制和仿真国家重点实验室(清华大学电机系),北京市,海淀区,100084
- 2. 重庆电力科学试验研究院,重庆市,渝北区,401123
- 折叠
摘要
Abstract
To limit short-circuit current and meet the requirement of setting of relay protection equipments, the partial neutral grounding of power transformers is adopted in 110 kV power systems in China, and this kind of grounding mode will result in overvoltage on the ungrounded neutral of power transformer. The overvoltage on ungrounded neutral of power transformer of an ll0kV system in Chongqing power grid is calculated by PSCAD/EMTDC software. Calculation result shows that the maximum power frequency transientovervoltage on the ungrounded neutral of power transformer will be 125.8kV; the voltage on the neutral of power transformer will came up to phase voltage while single-phase earth fault occurs in ungrounded system; under the condition of open-phase operation the ferro-resonance overvoltage with peak value of 261.2kV may result in the neutral of no-load power transformer and such a peak value seriously threatens the security of power equipments and the insulation of transformer neutral; lightning overvoltage can damage the insulation of transformer neutral, so it should be limited as well.Finally, a protection configuration scheme that is suitable to the neutral of 110kV power reansformer is given, and it is pointed out that when air-gap and arrestor are parallelly adopted, the restriction of arrestor on power frequency transient overvoltage on the neutral of power transformer should be taken into account.关键词
中性点/变压器/避雷器/间隙/工频过电压/雷电过电压Key words
neutral/ power transformer/ arrester/ air-gap/power frequency overvoltage/ lightning overvoltage分类
信息技术与安全科学引用本文复制引用
于化鹏,陈水明,余宏桥,杨鹏程,印华,吴高林..110kV变压器中性点过电压的计算及其保护策略[J].电网技术,2011,35(3):152-158,7.
