Assessment of Multirate Method for Power System Dynamics Analysis

As many power electronic converter interfaced technologies have recently been integrated into power systems, it has resulted in substantial computation demands and potential numerical instability issues in power system dynamics studies. Using a proper integration time step is key to solve these issues and multirate methods, which utilize a smaller time step to capture the system behavior associated with fast states and a larger time step for slow states, are an efficient way to represent current power system dynamics. This paper proposes a methodology to evaluate the system dynamic behaviors depending on different integration methods: a single rate method and a multirate method. These methods are compared with the results of rotor angle dynamic simulations using two different sizes of systems. Computational time and performance accuracy of the two methods are also assessed for the comparison.