Efficiency evaluation of the microgrid for selection of common bus using copula function-based efficiency curves of the converters

Abstract

Due to the increase in load growth, construction of renewable energy-based microgrids (MG) has been seen as the most economical and viable solution in the recent past. It leads to the need for feasibility investigation at the planning and design stage for appropriate selection of common bus (CB) type. One of the critical factors to determine the suitable CB is efficiency analysis. This paper proposes an efficiency evaluation method by using the copula function-based efficiency curves of the converters. The degree of association between percentage loading and efficiency of the converters is defined using best-fitted copula estimation, and a large number of iterations are performed using Monte Carlo simulations to generate the efficiency for each time instant. A variety of scenarios are simulated to determine when and which type of CB is most favourable. The efficiency of the MG is strongly dependent on the converter efficiency, number of converters in the MG, and seasonal variations, both in generation and load demand. The results indicate that DC CB has superior performance with the net efficiency gain ranging from 8.26% to 5.63% in all scenarios considered in this study. Moreover, DC CB is most advantageous in the MG with the DC load only. It will bring greater advantages in the future with the continuous development of renewable energy-based MGs and the increasing penetration of DC loads.