Dump load allocation in islanded microgrid with robust backward\forward sweep and MIDACO

Abstract

Dump load (DL) allocation in droop-controlled islanded microgrid (DCIMG) is vital to consume excess generation at off-peak hours and provide voltage and frequency (𝑽𝑽-𝒇𝒇) support. Furthermore, convergence of load flow (LF) solution is necessary to determine optimal working points of any DCIMG. Proposed in this paper, two LF methods based on the famous backward/forward sweep (BFS): improved special BFS (SBFS-II) and general BFS (GBFS). The former method is based on global voltage variable spread among all distributed generation (DG), while the latter is more general by considering local voltage measurement at each DG. The multi-objective problem of DL allocation in highly penetrated DCIMG to minimize 𝑽𝑽- 𝒇𝒇 deviations and power losses was investigated using the two LF methods combined with mixed-integer distributed ant colony optimization (MIDACO). The problem was applied to the IEEE-33 bus system, while solutions were subjected to various convergence tests. Results show SBFS-II and GBFS efficacy in calculation time and accuracy of the solution, respectively, for DL allocation problem in DCIMG.