Stability Oriented Chance Constrained Optimal Power Flow in Inverter Dominant Microgrids

The uncertain nature of renewable energy sources (RESs) always brings negative impacts on the system stability especially in inverter dominant microgrids. In this paper, we propose a stability oriented chance constrained optimization model incorporating the uncertainties of RESs outputs. In this model, the upper level aims to minimize the expected generation cost without violating the stability chance constraint; the lower level concerns about the stability index. Then, we assume that the RES output uncertainties follow Gaussian distribution and hence reformulate chance constraints into linear deterministic versions. With linearized constraints in hand, the bi-level model can be solved by Benders decomposition-based approach. Simulation results on the 33-bus microgrid reveal that compared to other benchmarking approaches, the proposed model has the capability of converging in much shorter CPU time with adopting the sensitivity cuts. The proposed model converges 10 times faster with more accurate solutions. And the stability index is dramatically enhanced as well as the benefit for bus voltage security.