Dynamic state space power system load model

The load model in power system stability studies has been shown to be a very important factor in determining the stability of a generator or stability transfer limit of a transmission line. Present load models currently in use make it difficult to model the dynamic response of power system loads. The only practical means for estimating the dynamics of power system loads is from actual system measurements. Presented herein is a proposed state space linear load model whose parameters can be estimated easily from system measurements of actual load response. A second order state space load model was developed and adapted for parameter identification. A weighted least squares identification process was programmed to identify model parameters from measurements of load current response due to changes in input voltage. An induction motor model response was used to provide measured input-output load response. The state space load model was implemented in a typical power system stability program. The application of the state space load model in transient stability studies demonstrates it can more accurately reflect actual load response than conventional stability load models. The state space load model is shown to adequately model the dynamics of power system composite bus load or external system equivalents.