On simplified handling of state events in time-domain simulation

The power system models typically used in dynamic simulations involve discrete events in addition to the standard differential-algebraic equations. Those events cause the system to jump from one continuous behavior to another. Solvers have to handle those jumps. This paper focuses on simplified time simulation where large steps are used in conjunction with stiff-decay integration methods to obtain approximate solutions in short computing times. In the proposed simulation scheme, the simulation time steps are not synchronized with the system jumps, which are treated a posteriori in a corrective step. In this context, the paper analyzes several simple nonlinear models involving limiters, switches, minimum gates, etc. from which some precautions to be taken at the modelling and solving stages are stressed. The paper also reports on results obtained with a representative power system model.