A Dynamic Load Model for Analysis on the Power System Voltage Stability

Abstract

During recent years, it has become remarkably important to protect from the voltage instability of power systems according to the tendency of hevily loading and the concentration of air conditioning loads on certain hours. The many studies have advanced elucidations on the problems and the countermeasures are filling up. However, the load representations used in those studies of the phenomena are based on power values, i. e., P and Q, therefore these analytic models are insufficient to express the load responses strictly, and feasible inverstigation regions are limitted.
In this paper, a load model expressing load admittance responses by a first order delay differential equation is introduced and studied to apply this model combining with power network solutions for analyses of the power system voltage stability, then this load model is shown to work reliably and effectively. Using this model, it is possible to investigate more precisely and widely than before the power system voltage stability phenomena such as one on arbitrary characteristic loads, in lower voltage ranges and on propagations of instability through the networks.