Arc flash in large energy storage systems. Hazard calculation and mitigation

This paper deals with the arc flash hazard calculation in large energy storage systems (ESSs), with specific reference to battery energy storage systems (BESSs) and supercapacitor energy storage systems (SESSs). Due to the lack of international harmonized standards and the growing use of large ESSs, the evaluation of arc flash hazard associated with BESS maintenance operation is an interesting subject. In this study, battery circuit models, based on experimental short-circuit tests carried out by TERNA (the Italian transmission system operator) and a simplified supercapacitor circuit model, both coupled with a nonlinear arc resistance model, are used to assess the incident energy related to arc flash in BESSs and SESSs, respectively. Efficient and cost-effective solutions, able to reduce incident energy below the safe value 8 cal/cm2and based on the installation of fast-acting fuses, are then proposed and discussed.