Modeling of potential transformers in gas insulated substation for the very fast transient simulation

A high frequency (>10 MHz) circuit model for an inductive potential transformer in GIS is set up. First, the transfer function model for the PT is set up by means of vector fitting based on testing data. Second, the order of the transfer function is reduced according to the practical needs. At last, a special method of RLC synthesis for transfer function is used to set up the circuit model of PT. The proposed method for modeling of high frequency PT is simple, effective and general and can be used to the modeling of any kind of instrument transformer as well.