Security Evaluation of Voltage Controlled Active Distribution Network at Point of Common Coupling

Voltage control of point of common coupling (PCC) for a combined system with distributed generation (DG) and energy storage (ES) on distribution network side, which can improve the regulation ability of the distribution network to renewable energy and the overall voltage quality. In this paper, extended QV bus type is used to model the power output characteristics of the DG+ES combined system with PCC voltage control. Then, a probabilistic load flow model with QV bus type and an analytical algorithm are proposed to realize the probabilistic modeling of the operation for active distribution network and improve the solving efficiency. Furthermore, the key indicators for the safe operation of distribution network thus as over-limited probability of voltage, confidence range of voltage fluctuation, and the over-limited probability of transmission power are presented to quantify the operation risk. Finally, simulation results are compared and analyzed to demonstrate the rationality and effectiveness of the proposed method and model.