DEVELOPMENT OF A DYNAMIC ZIP-MOTOR LOAD MODEL FROM ONLINE FIELD-MEASUREMENTS

We developed, using on-line field measurements, a dynamic ZIP-motor lo ad model which attempts to capture the dynamic behavior of lends, The dynamic ZIP-motor load model consists of two parts: a static part and a dynamic part, where the static load is represented by a combination of constant impedance, constant current and constant power while the d ynamic load is represented by an induction motor model, A procedure fo r building the model structure of the dynamic ZIP-motor load model is developed. An effective solution algorithm for estimating the associat ed model parameters is presented. A notable feature of the algorithm i s that the model parameters are estimated based upon pseudo-gradient i nformation instead of exact gradient calculation. The proposed algorit hm is easy to implement and can be used to identify nonlinearities ass ociated with ZIP-motor models, such as models accounting for magnetizi ng and leakage reactances. The results developed in this paper are tes ted and evaluated using real field measurements from a real power syst em. It is shown numerically in the case study that the developed dynam ic load model can accurately capture the dynamic behaviors of loads. ( C) 1997 Elsevier Science Ltd.