Continuously increasing demand of microgrids with high penetration of distributed energy generators, mainly renewable energy sources, is modifying the traditional structure of the electric distribution grid. Major power consumer countries are looking for alternative energy sources to avoid the impact of higher fossil fuel consumption. Thus, different policies have been promulgated to promote renewable energy technologies (RETs) and distributed energy resource (DER) deployment and are encouraging technological innovation. These policies aim to reduce greenhouse gas (GHG) emissions and achieve energy security and independence to meet an ever-increasing electricity demand. Many studies have been performed on the successful integration of RET and DER operation and control, protection and stability issues, all simultaneously and satisfactorily implemented during feasible microgrid operation. However, apart from the technical challenges, few microgrid studies exist on effective policies and incentives for microgrid promotion and deployment. This survey investigates the policy, regulatory and financial (economical and commercial) barriers, which hinder the deployment of microgrids in the European Union (EU), United States (USA) and China. In this paper, a clear view on microgrid policy instruments and challenges are investigated to aid future developments.

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In this paper, we investigate transportation problem in which supplies and demands are intuitionistic fuzzy numbers. Intuitionistic fuzzy zero point method is proposed to find the optimal solution in terms of triangular intuitionistic fuzzy numbers. A new relevant numerical example is also included.

Recently, nanofluids are introduced in the power utilities for the dielectric performance enhancement of power transformer oil. The compactness and fault improvement of the power transformers has resulted in the necessity of next-generation insulating fluid with inflated dielectric properties. This paper investigates the dielectric performance of the novel ester oil-based magnetic nanofluids with different nanoparticles under different electric stress conditions. Two biodegradable fluids used as the base liquid for the experiment are synthetic ester oil and natural ester oil while three magnetic nanoparticles used to synthesize nanofluids are iron (II, III) oxide, cobalt (II, III) oxide, and iron phosphide. The concentrations of the nanoparticles are varied to optimize the characteristics of the prepared nanofluids. The dielectric breakdown and relative permittivity of the nanofluids have been experimentally investigated. Further, the breakdown predictions have been performed using Weibull statistical distribution-based regression analysis. The experimental results show the improvement in the characteristics of prepared nanofluids with the change in nanoparticle concentration as compared with the host fluids.