摘要
在高压直流输电系统中,换流变压器是连接交流系统和直流系统的核心设备,它的稳定运行直接影响着直流输电系统的可靠性。变压器在空载合闸时会产生励磁涌流,并在不同的合闸角时,产生不同大小的励磁涌流,最大可达额定电流的8~10倍,同时会使变压器两侧的电流互感器饱和,由于三相电流互感器暂态特性的不一致会出现较大差流,有可能使变压器差动保护误动。文中结合直流输电工程中的事故实例,基于实际的控制保护模型与PSCAD/EMTDC仿真平台,采用实际故障录波分析和仿真分析相结合的手段,系统地分析了换流变压器空载合闸的励磁涌流特性,并提出了有效的励磁涌流的抑制方案。
In the HVDC system,the converter transformer is one of the most important equipment connected to the AC system and DC system,and its the stable operation has direct impacts on the reliability of the HVDC system.When the transformer is closed on no-load,inrush current is generated,and at different closing angles,it could be up to 8~10 times of the rated current,which may saturate CTs at both sides of the transformer.Due to inconsistency of three-phase CTs＇ transient characteristics it could lead to misoperations of the transformer differential protection.Considering the actual accident in the HVDC project and based on the actual control and protection model and PSCAD/EMTDC simulation platform, this paper systematically analyzes the magnetizing inrush current charac-teristics of the converter transformer under no-load using combination of actual fault recording analysis and simulation analysis,and puts forward effective suppression schemes for inrush current.
出处
《电网与清洁能源》
北大核心
2017年第1期64-70,78,共8页
Power System and Clean Energy
基金
国家自然科学基金(51377059)~~
