Field-Circuit Coupled Simulation of Core Grounding Current of a VSC Transformer

The structure and operation conditions of VSC transformer are different from those of power transformer and converter transformer. The core grounding current of VSC transformer is affected by many factors. A method for computing the grounding current of a transformer is proposed. Firstly, a geometric model is established to characterize each metal structure in the transformer. Secondly, a finite element model of electrostatic field is established and the partial capacitance matrix is calculated. Lastly, the circuit simulation model of the transformer can be obtained from the partial capacitance matrix, by which the grounding current can be computed.