Electrical Safety Considerations in Large-Scale Electric Vehicle Charging Stations

Abstract

Several safety regulations, particularly concerning the charging of electric vehicles (EVs) are developed to ensure electric safety and prevent hazardous accidents, in which safety requirements for the EV supply equipment (EVSE) and the EV battery are two main driving factors. At present, quantitative assessment of electrical safety considering the operation conditions of large-scale EV charging stations (EVCSs) has still remained a challenge. Driven by the hierarchy of hazard control mechanisms, this article proposes a holistic approach to evaluate the electrical safety of the large-scale EVCSs when coupled to renewable power generation. Our approach mainly focuses on several topics on the operational safety of EVCS primarily concerning: 1) the facility degradation which could potentially result in a compromised EVSE reliability performance and EVCS protection failure; 2) the cyberattack challenges when the smart charging and the communication between EVCSs and electric utilities are enabled; and 3) the potential mismatch between the renewable output and EVCS demand, which could trigger the system stability challenges during normal operation and inability to supply the critical EV loads during outages. The proposed framework will provide informative guidelines to the EVCS operators for continuous monitoring and effective management of the day-to-day EVCS operation.