Impact Assessment of Wide-Scale Rooftop PV Penetration on Overcurrent Protection of Distribution Networks

The increasing penetration of photovoltaic (PV) generators installed in low voltage networks has raised concerns about the potential impacts of these devices in overcurrent protection. As these generators are installed in a wide-scale and widely dispersed fashion in low voltage networks, they may require new study methods by utility engineers, which traditionally deal with few large synchronous generators connected at medium voltage level. To clarify whether new study methods are in fact needed or not, this paper provides a detailed analysis of the potential impacts of PV generators on the network overcurrent protection. Coordination and selectivity among circuit breaker, recloser, lateral and service transformer fuses are assessed by considering high levels of PV penetration. The full protection scheme, installed in substation, main feeder, feeder lateral, and service transformer is evaluated. Results reveal that, even under high PV penetration scenarios, the contribution of PV generators to short-circuit currents is not large enough to affect the protection scheme of the studied system.