Measurement of dc Arc-flash Incident Energy in Large-Scale Photovoltaic Plants: A Basis for Standardization

The deployment of high-power dc equipment is increasing in solar photovoltaic (PV) plants, but very few studies have quantified dc arc-flash risks. Currently, PV plant owners and operators rely on theoretical, simplified models, such as those in NFPA-70E and other publications for the assessment of risk associated with dc arc-flash. This paper presents an overview of arc-flash risks in a PV system based on a series of field experiments based on IEEE-1584 in two large-scale groundmounted PV plants. The experiments include various high-power dc equipment of a PV plant such as central inverters, combiner boxes, recombiner boxes, string inverters, and multiple configurations of electrodes in a 20-inch calibration cube. The study reveals the none of the available dc arc-flash models are applicable for a PV plant. This work is an important first step towards developing an improved model that more accurately assesses dc arc-flash risk in a PV plant.