Modeling of stalled motor loads for power system short-term voltage stability analysis

Stalled motor loads, particularly stalled residential air-conditioner and refrigeration motor loads, have been determined to be the most important cause of delayed voltage recovery following several major utility system disturbances. The accurate modeling of stalled motor loads has been demonstrated to be critical in identifying potential delayed voltage recovery or voltage instability problems in transmission systems through dynamic simulations. A simple methodology for modeling the effects of stalled motor loads for short-term voltage stability analysis is presented and evaluated using a sample utility system.