Stray Current DC Corrosion Blind Spots Inherent to Large PV Systems Fault Detection Mechanisms: Elaboration of a Novel Concept

This paper elaborates on a new issue that should progressively receive attention by photovoltaic (PV) installation industry and utility-management entities. It specifically introduces stray current corrosion blind spots that are inherent to PV systems' grounding and associated dc ground fault detection mechanisms. These blind spots arise as the existing thresholds for dc leakage currents have been based on other issues, such as fire or personnel safety. Leakage current may cause accelerated corrosion on PV supporting metallic structures as well as on third-party metallic utilities that may be present in the vicinity of PV installations. The impact of dc stray current corrosion is recognized by the stakeholders across the world in the dc traction community and codes and standards have been developed to provide designers and utility companies with a corrosion-management strategy that defines a level of corrosion risk which is acceptable across infrastructures. This paper outlines the theoretical background that will assist the understanding of stray current corrosion by PV plant developers, designers, and owners and raise awareness with the utility distribution network owners.