Analysis of grounded and ungrounded photovoltaic systems

Grounding has always been a subject of controversy during discussions of electrical systems. Grounding techniques and requirements, like language, vary from region to region and country to country. Optimized grounding for personnel protection does not optimize the fire safety of a system and grounding for fire safety does not optimize personnel safety. Grounding to provide protection for equipment requires a third set of requirements. Photovoltaic (PV) power systems are current sources and require different grounding techniques than conventional voltage sources. Distributed leakage paths, multiple fault paths, and new roles for fuses and circuit breakers are among a few of the new issues that need careful consideration. This paper presents and analyzes the grounding issues associated with PV energy sources. Grounding configurations, faults, personnel safety, fire safety, and surge protection are addressed.