Based on this new model, steady state DC analysis and small signal AC analysis can be used to analyse all kinds of converters.

In this paper, starting from the conversion of Z parameters and Y parameters of two-port parameters, we deduce the formulas of wye-delta network transformation in sinusoidal steady-state.

The fault phase selectors, including the phase current difference suddenly-change and the sequence current, may misoperate in some cross country faults and conversion faults.