Advanced Load Models in Power System Dynamic Studies: Application Issues

Power system dynamic performance has long been recognized as a function of the types of models used to represent system loads. In general, the impact of load model used on results can range from insignificant to extremely significant depending on the study being done and other assumptions made. Given that bulk transmission study results often drive investments of 10s of millions of dollars, it is common for engineering prudence, competitive pressures, or legal challenges to lead a very close examination of study assumptions, including modeling. The need to "justify" study results often leads to significant engineering time devoted to sensitivity analyses related to study assumptions. Assumptions related to load models have been shown to be particularly important in angular and voltage stability studies, especially when dealing with shorter-term responses where the system disturbance is often greater. This paper is written with the intent of providing a summary of the application issues associated with including advanced load models in dynamic studies so that ongoing work related to load modeling may result in the most usable results possible