Voltage-Based Protection Scheme for Faults Within Utility-Scale Photovoltaic Arrays

Permanent power loss and major catastrophic failures are among the potential consequences of undetected faults within photovoltaic (PV) arrays. This paper proposes a voltage-based protection scheme that detects, classifies, and locates string-to-ground, string-to-string, and open-circuit faults in utility-scale PV arrays. The protection scheme operates based on the magnitude and wave-shape properties of voltage signals. Some salient features of this method include its capability to distinguish between fault and partial shading conditions, and its independence from meteorological data. The performance of the proposed approach is assessed on two utility-scale grounded PV arrays under various conditions. Moreover, the proposed method is tested on an experimental setup of a small grid-connected PV array. Simulation and experimental results verify the scheme's accuracy, high speed, and scalability.