Optimal renewable distributed generation planning: an up-to-date state-of-the-art review

Due to its multiple benefits, the integration of renewable-based distributed generation (RDG) into the distribution network (DN) is of great importance. Yet, given the complexity of this network, optimal distributed generation planning (ORDGP) is considered a complex combinatorial problem, which remains a real challenge for investigators, decision-makers, and investors. This issue involves finding the optimal locations, sizes, power factors, and number of RDGs to be incorporated into the DN to improve the network's overall efficiency while meeting a set of voltage, current, and power constraints. Moreover, the incorporation of uncertainties related to this type of source, especially wind turbine or PV system, decreases the ability of classical and analytical methods to solve the ORDGP problem. For this reason, meta-heuristic and hybrid methods have become very promising essentially because of their randomness. In this context, a systematic and comprehensive literature review on the different definitions, classifications, and interests of RDG, as well as on the different optimisation techniques, represents the main objective of this study. Concisely, this paper provides in-depth knowledge and serves as a useful guide for future researchers and investors in the ORDGP.