配电网三相电压不平衡的成因分析和实践

Cause analysis and practice of the unbalanced three-phase voltage in distribution network

针对配电网正常运行状态下长期存在的一起变电站母线三相电压不平衡问题,通过实际运行数据和三相潮流仿真过程,深入分析了长期存在的母线三相电压不平衡的原因。研究表明,不接地配电网挂接不平衡的电容型电压互感器,其存在的电容值容易造成系统的正常运行状态下的三相不平衡。将该分析流程用于工程实际的电压不平衡的成因分析过程中,通过三相潮流和现场数据能够最大限度地减少分析工作量,提高效率,为后续的不平衡问题治理提供方向。

Aiming at the long-standing three-phase voltage imbalance problem of substation bus in normal operation state of distribution network,through the actual operation data and three-phase power flow simulation process,the reasons for the long-standing three-phase voltage imbalance of bus are analyzed in depth.The research shows that the unbalanced capacitive voltage transformer is connected to the ungrounded distribution network,and its capacitance value is easy to cause the three-phase unbalance under the normal operation state of the system.The analysis process is used to analyze the causes of voltage imbalance in engineering practice.Through three-phase power flow and field data,the analysis workload can be minimized,the efficiency can be improved,and the direction for subsequent imbalance problem management can be provided.