The Effect of Power Electronic Loads on Western Interconnection Stability

The prevalence of power electronics in the bulk power system is increasing rapidly in both the generation and consumption of electricity. This work focuses on the effect of changing load composition - specifically the transition from single phase air conditioner motors to power electronics backed air conditioners - on power system stability. Various transmission and generation contingency events for the Western Interconnection were simulated using Positive Sequence Load Flow software and planning models from the Western Electricity Coordinating Council. In general, an increased proportion of power electronic load leads to more instability. For some specific faults resulting in fault-induced delayed voltage recovery, transitioning to higher proportions of power electronic loads helps expedite system recovery. These results demonstrate that load composition should be examined in conjunction with generation composition when evaluating system stability.