Load Stability Index for Short-term Voltage Stability Assessment

Short-term voltage stability is closely related to the dynamics and stability of load models. After the identification of the load model parameters, the load stability can be analyzed. In this paper, a load model parameter based load stability index is proposed, with desirable properties of case independency, sufficiency and monotonicity. The composite load model structure together with the identification method is introduced. Then, the dynamics of the load model under voltage disturbance are analyzed and the basic form of the load stability index is proposed. After that, the basic index is modified in order to be more sufficient based on the simulation results in WSCC 9 bus system and then the final form of the index is given. Finally, the index is validated based on the simulation results to show that it can be used to reflect the ability of a load model to maintain the power consumption stable.