Effects of the Incorporation of Electric Vehicles on Protection Coordination in Microgrids

Abstract

Amid growing concerns about climate change, electricity-powered transportation systems stand out as an opportunity to help in reducing fuel consumption. Electric vehicles (EVs) would connect to the grid using clean, renewable electricity; however, the interconnection between EVs and the grid brings about new challenges for traditional power systems. Plug-in hybrid EVs and plug-in EVs have started to become more prevalent in the system; therefore, their impacts and benefits are also of concern. Among these concerns is the detailed analysis of the impact that EVs may have on short-circuit levels in microgrid protection schemes. In this context, the main contribution of this paper is a detailed evaluation of the impact of EVs on the short-circuit levels and protection coordination schemes in microgrids. For this purpose, a methodology was proposed to measure the impact of EVs on the protection coordination schemes in microgrids using different evaluation indices. The proposed approach was validated on a benchmark IEC microgrid considering different operative scenarios that envisage several levels of EVs penetration. The results evidenced the applicability of the proposed approach and allows to conclude that the incorporation of EVs in microgids impacts the performance of the protection schemes, specifically with respect to short-circuit levels.

Keywords

• electric vehicles
• microgrids
• overcurrent relays
• protection systems