A Modified Load Flow Algorithm for Microgrids Operating in Islanded Mode

A modified load flow algorithm for microgrids operating in islanded mode is developed in this paper. The proposed algorithm is able to perform load flow calculations in networks without making use of the slack bus concept, and is suitable for applications to islanded microgrids. The developed algorithm includes the explicit representation of the steady-state characteristics of microsource controllers, making it possible to perform the load sharing between all generating units. Through this approach, the mathematical concept of a slack bus is not anymore necessary, since the load and the network losses are distributed among all generating units according to the steady-state characteristics of their respective controllers. The results obtained by applying the proposed algorithm to a microgrid test-system are validated through comparisons with steady-state values obtained through nonlinear time-domain simulations of the same test-system, performed with the PSCAD/EMTDC software package.