A new continuation power flow model for simulating time-domain dynamic load restoration

It is necessary to simulate accurately the voltage response characteristics of load in voltage stability assessment and control of power system. The post-contingency load dynamic restoration is one of the direct reasons of mid-long term voltage instability or voltage collapse. A new continuation power flow (CPF) model for simulating the load time-domain dynamic restoration is proposed in this paper. The restoration process of load is transformed equivalently into the continuous variation of parameters in static load voltage model. The homotopy parameterization methods based on both the ZIP polynomial load model and the exponential load model are given. The sensitivity formulation of the continuation parameter with respect to any control at the critical points is presented. The proposed CPF model can be taken as a new method for identifying the voltage unstable contingencies. The numerical results with IEEE118 bus test system show that the proposed model and method is effective in simulating the load time-domain restoration characteristic, unstable contingency identification and the sensitivities for preventive control.