Variable step integration method on power system transient simulation with multiple switching events

Numerical oscillation problem and multiple switching events in power system electromagnetic transient simulation with power electronic devices are discussed in this paper. And then a variable step integration method considering multiple switching events is proposed, based on backward Euler method. In this method, linear interpolation is to change the switch state, and the variable step backward Euler method is used to the numerical integration. There are several advantages of the proposed algorithm, including effective treatment to multiple switches, significant inhibition to numerical oscillation, and favorable adaptability to step size. The effectiveness and efficiency of the algorithm are studied on typical power electronic rectifier circuit and simplified high voltage direct current transmission system, and the validity is also proved compared with the simulations by PSCAD.