Dynamic Load Models Derived from Date Acquired During System Transients

For several years power system load responses have been recorded during system transients by means of a remote data acquisition system developed by Ontario Hydro. Using these data, models for the loads are developed in the paper and parameters for the models are obtained. Conventional static load models are shown to represent adequately the characteristics of a residential/commercial feeder load. For large rotating industrial loads two models are developed. The first is a transfer function model which relates the small signal power and reactive power outputs to input changes in voltage and frequency. The second is an induction motor model with shunt static load. Recorded voltage is considered as an input to the model and the output real and reactive power are compared with the measured output. The weighted squared error between the measured output and the model output is minimized by obtaining optimum model parameters. Recorded and simulated responses of the paper mill loads are compared.