摘要
该文分析了换流变压器空载合闸时产生空投涌流、对称性涌流、和应涌流机理及其基本特征,分析了星角变压器空载合闸时角侧环流与星侧中性点零序电流的内在关系,定义了由星角变压器和星星变压器构成换流变压器组的复合环流与复合零序电流,推导了一组换流变压器的复合环流与复合零序电流在空载合闸涌流和内部接地故障情况下的关系表达式,提出了基于复合环流与复合零序电流波形相关系数的换流变压器励磁涌流识别新方法以及差动保护方案。理论分析和仿真验证表明,新方法可以有效避免换流变压器差动保护在涌流时误动以及空投于故障时拒动的情况,有效提高了换流变压器运行安全性,保障交直流系统可靠运行。
The mechanism and basic characteristics of the ordinary magnetizing inrush, symmetrical inrush and sympathetic inrush during the no-load switching of the converter transformer were analyzed. The composite circulation and composite zero-sequence current of the converter transformer group with the star-angle transformer and the star-star transformer were defined. By analyzing the intrinsic relationship between the angular circulation of the star-angle transformer and the zero-sequence current of the neutral side of the star side, the composite circulation and composite zero-sequence current of a group of converter transformers were deduced under the condition of no-load closing inrush and internal ground fault. Based on the relational expression, a new method and differential protection scheme were proposed to identify the inrush current of converter transformer based on the correlation coefficient between composite circulation and composite zero-sequence current. Theoretical analysis and simulation results show that the new method can effectively avoid the misoperation of the converter transformer differential protection during the inrush current and the refusal of no-load closing with faults, effectively improve the operational safety of the converter transformer and ensure the reliable operation of AC-DC system.
作者
李斌
彭伍龙
姚斌
范玲
李鹏宇
王兴国
杜镇安
LI Bin;PENG Wulong;YAO Bin;FAN Ling;LI Pengyu;WANG Xingguo;DU Zhen’an(Key Laboratory of Smart Grid of Ministry of Education(Tianjin University),Nankai District,Tianjin 300072,China;China Electric Power Research Institute,Haidian District,Beijing 100192,China;State Grid Hubei Electric Power Research Institute,Wuhan 430000,Hubei Province,China)
出处
《中国电机工程学报》
EI
CSCD
北大核心
2020年第24期8027-8038,共12页
Proceedings of the CSEE
基金
国家电网有限公司科技项目(SGHBDK00DWJS1900067)。
关键词
换流变压器
对称性涌流
和应涌流
复合环流
复合零序电流
波形相关系数
converter transformer
symmetric inrush
sympathetic inrush
composite circulation
composite zero-sequence current
correlation coefficient
