Reliability evaluation of multi-microgrids considering optimal operation of small scale energy zones under load-generation uncertainties

• In this paper considering probabilistic behaviors, the optimal power dispatch problem is solved.
• System reliability is evaluated in two different structures of MGs, namely interconnected and isolated structures.
• The uncertainties are available in load and generated powers by small scale energy resources (SSERs).
• The advantages of interconnected MGs are compared with islanded mode.
• Imperialist competitive algorithm is adapted as optimization algorithm and the Monte Carlo Simulation (MCS) method is used to compare the results.

A Microgrid (MG) is a scaled down version of the centralized power system that generates, distributes, and regulates the flow of electricity and efficiently serves the local demand. It can operate either grid connected or islanded and, if required, can switch between two modes. In this paper the optimal operation of interconnected MGs considering market operation and network reliability based on MGs is discussed. In supposed structure of MGs, each MG is considered as small scale energy zone (SSEZ) and energy sources within MGs play a role of small scale energy resources (SSER). Because of unpredictable behavior of some SSERs and consumption power of MGs, the probabilistic analysis is impossible to ignore. So, the reliability evaluation is done under uncertain behavior of MGs components. Some recently introduced reliability indices in the literature for MGs are used to evaluate the MGs reliability. The reliability in the proposed paper is evaluated in two different structures of MGs. In first structure, the MGs are interconnected and in second structure, all MGs in islanded mode. The imperialist competitive algorithm (ICA) is applied to optimal power dispatch problem and the obtained results are compared by Monte Carlo Simulation (MCS) method.