Mitigating Arc Fault Risk in PV Systems

Southern California Edison’s (SCE) and Eaton’s discussion focuses on arc fault risk and mitigation on solar photovoltaic (PV) projects.  Through its Solar Photovoltaic Program (SPVP), SCE develops utility scale solar photovoltaic (PV) projects on commercial rooftops (along with a small number of ground mounted projects) throughout its service territory.  SCE and Eaton have investigated arc fault detection on these solar arrays, and provide the results to industry participants as part of their commitment to sharing lessons learned.

SCE and Eaton discuss: the risk of arc fault events and the consequences for rooftop PV systems; new National Electric Code (NEC) code requirements (2011 NEC Code 690.11 requires series DC arc fault circuit interrupters); types of arc faults; means of detection; and future opportunities for DC arc fault solutions.  SCE and Eaton have worked together to conduct arc fault event studies including: measurement and detection of simulated series arcing faults in a large commercial PV DC system at both the string and bus feeder level; installation and testing of an Arc Fault Detector (AFD) that will recognize arcing events and logging nuisance events over time; and measurement and capture of waveforms. Results of these studies support increased means of detection and development of solutions to arc faulting.