The 500kV power grid is the most important high-power AC power system in China. The 500kV transformer is responsible for the regular uploading and sending tasks. It is important electrical primary equipment that connects two or even three different voltage levels. Taking a new 500kV transformer in Chongqing as an example, this paper discusses the influencing factors of 500kV transformer inrush current when connected to the grid through PSCAD/EMTDC software, and puts forward feasible measures to suppress the inrush current.

When the converter transformer is closed at no load state, the transient voltage is too large, which may cause the transformer core to saturate; meanwhile, the capacitance of the cable line to the ground is much larger than that of the overhead line, which may cause ferromagnetic resonance phenomenon. Taking the parameters of typical transmission line and 500kV converter transformer as an example, the simulation results of Matlab are used to analyze the possible effects of no-load closing of converter transformer under different cable-forming rates and different outlet modes, and put forward targeted measures, which have certain reference value for the future design of the converter station outline.

No abstract