Dynamic load models: Where are we?

Despite the lessons learned over years of load research, the power industry for the most part continues to use very simple functional models to represent loads in power system dynamic simulations. Even with some refinements such as the addition of induction motors, it has been demonstrated that in some cases these models are inadequate to properly characterize phenomena that are critical to power system performance, such as motor stalling. A more appropriate load model structure has not been adopted formally due to the increased complexity that it introduces, and the effort involved in assembling the data required in a consistent and verifiable manner. This paper discusses the current load modeling practice in the Western Electricity Coordinating Council (WECC), and describes efforts currently underway to define a more appropriate load model for general use in dynamic simulation.