A General Framework for the Power Flow Solution in Radial and Meshed AC/DC Microgrids

The advent of AC/DC microgrids generated the need to research and develop power flow algorithms to assist in the planning of these microgrids. The main objective of the research carried out in this paper is to present a general framework for the power flow in AC/DC microgrids with multiple interlinking converters. This framework is based on the superposition principle and the solution of small nonlinear subproblem to determine the angular frequency, power flow through interlinking converters and voltages at the reference nodes. This framework was used to derive two algorithms: one based on the Current Summation Method, for radial microgrids, and another based on the Gauss-Zbus Method, for meshed microgrids. Test results with 45 and 906 nodes microgrids showed that the proposed power flow algorithms have: (i) the same accuracy as the Newton-Raphson Method; (ii) good scalability in terms of computational cost; (iii) robustness against random variations in microgrid parameters (the number of iterations varies only from 4 to 5) and branches contingencies; (iv) computational costs savings of 81% to 98% compared to the Newton-Raphson Method; (v) speed up from 5 to 44 times in relation to the Newton-Raphson Method; (vi) fast convergence characteristic.