Simulation of Short Circuit to Ground of Transformer Winding Based on MTL Model

Internal overvoltage of transformer caused by VFTO can threaten the security of the transformer. When the pulse wave invades the transformer with short-circuit fault to ground, the extremely uneven voltage distribution in the internal windings will not only endanger the safety of windings but also affect the stability of power system. The internal distribution parameters of the transformer winding model is necessary for the analysis of the short-circuit fault to ground based on MTL theory. By establishing a distributed parameter model of the transformer winding model with 16 turns, this paper analyzes the influence of the variation of distribution parameters in case of short-circuit to ground fault, then the modified short-circuit model to ground is applied to a transformer winding model with 180 turns. The results show that the modified model can well simulate the change of short-circuit fault to ground. The voltage waveform distribution between turns is extremely uneven.