Hierarchical Generation Rescheduling And Robust Load Shedding Scheme Considering The Uncertainty Of Distributed Generators

摘要

Load shedding is the last resort to prevent power system collapse. When commutation failure occurs in HVDC converter station, the receiving system will meet huge power shortage. To maintain the stability of receiving power system, this paper proposes a load shedding scheme with hierarchical control structure, in which the distribution networks are divided into several control areas. Inappropriate load shedding strategies may lead to consequential DG outage caused by voltage violation. For each area, a two stage robust load shedding optimization model considering voltage constraints is developed, which can capture the uncertainties of load demand and distributed generators output. Since AC load flow with voltage constraints is incorporated in this optimization model, the voltage violations can be eliminated during load shedding. Furthermore, to accurately simulate the impact of external network of each control area, the Thevenin equivalent model is formulated and its parameters are estimated using local measurements. In this two stage model, the first stage generates the optimal control decision and the second stage seeks the worst-case fluctuation scenarios. The model is formulated as a mixed integer linear programming (MILP) and solved by column-and-constraint generation method. Numerical experiments demonstrate the efficiency of the proposed method.