Fault Characteristics Analysis on 56-Bus Distribution System with Penetration of Utility-Scale PV Generation

With the dramatic transition in distribution power systems from centralized fossil-based power plants to distributed energy resources (DERs), the system fault characteristics, especially the fault current profile, is likely to undergo some considerable changes, which may impose a negative effect on the dependable operation of system protective relays and complicate the design and configuration of protection schemes. This paper has studied the impacts of a high penetration level of inverter-based photovoltaic (PV) generations on a 56-bus distribution feeder under short-circuit faults, with the PV inverter control scheme in compliance with the IEEE Standard 1547–2018. The power system fault responses under both the PV inverter grid-following control mode and the grid-forming control mode were discussed. The fault current profile was analyzed under various different fault scenarios, including both three-phase and single-phase faults, under different fault severity and at different DER relative locations. The potential issues in distribution system overcurrent relay caused by the fault current contribution from utility-scale DERs are also stated.