Stochastic Backward/Forward Sweep Power Flow Analysis for Islanded Microgrids

摘要

Distributed generation-based islanded microgrids lack a constant reference voltage node, making it difficult to compute the power flows in the microgrid using traditional power system analysis tools. In this work, we model the droop equations that allow voltage and frequency regulation among the distributed sources in the backward/forward sweep algorithm. As a result, the system frequency is one of the unknown state variables that has to be computed by power flow analysis. Since the backward/forward sweep algorithm is primarily applied only to radial distribution systems, the algorithm is then modified to extend its applicability to weakly-meshed microgrid topologies. The distributed generation units are modelled as solar generation with their uncertainties defined by Beta distribution while the load uncertainties are modelled using normal distribution. Finally, a stochastic islanded microgrid power flow tool is developed using the polynomial chaos approximation technique.