Measured and Calculated DC Arc-Flash Incident Energy in a Large-Scale Photovoltaic Plant

Abstract

There is a growing amount of high-power dc equipment being deployed, including solar photovoltaic (PV) plants, but very few studies have measured and quantified dc arc-flash risks. Most dc arc-flash literature is based on the theory and, when their theoretical calculations are applied to real-world conditions, can significantly deviate from actual measured values. For PV, the nonlinearity of the power source (i.e., PV modules) creates an additional level of uncertainty for theoretical approaches. This paper quantifies the thermal hazards from arc flash in a real-world 1000-kWdc PV plant by measuring arc current, arc voltage, and incident energy (IE) and then compares results against existing IE models. The study reveals that none of the available models adequately represent real-world hazards. It is also found that a PV source acts as a sustainable constant-current source during an arcflash event. This paper is an important first step toward developing an improved model that more accurately assesses dc arc-flash risk in a PV system.