Kalman Filter Based Approach for ZIP Load Modeling for Aggregate Loads

Constant impedance, constant current, constant power (ZIP) load modeling has been used in various power system applications. It is of great interest to accurately estimate ZIP parameters. This paper presents the Kalman filtering based technique for estimating load ZIP parameters. In addition, aggregate load modeling is a common practice in utility companies. However, there are certain factors that can affect estimation results. This paper formulates the aggregate ZIP load modeling and provides insights into the effects of load connections and voltage unbalance on ZIP load modeling. The effects of voltage unbalance and load connection type on ZIP load estimation are illustrated through examples. Representative case studies based on the IEEE 34-bus system built in OpenDSS are reported.