This project addresses utility concerns related to the fault contribution from renewable generators, most prominently wind and solar generators. Accurate information of these fault contributions is needed for selecting equipment ratings and ensuring that the protective device coordination in power systems functions properly. The fault contribution from renewable generators, in particular inverter-based renewable generators, is fundamentally different from the fault contribution from conventional generators and much uncertainty exists regarding how to account for renewables when sizing equipment and setting relays.
This report provides engineers who conduct protection coordination studies with the needed information regarding fault characteristics of inverter-based technologies. The fault contributions from generators that employ inverter-based technologies are determined based on (1) previous research, (2) a brief survey of inverter manufacturers, and (3) wind turbine generator and PV generator modeled that EnerNex developed in close collaboration with turbine vendors and PV manufacturers. In addition to the literature review, survey, and model development effort, we conducted four case studies that investigated the impact of inverter-based generators on system protection and compared simple current source models often employed in software application tools, which are used for protective coordination studies with sophisticated transient model representations of inverter-based generators.
Keywords: Inverter-based generation, distributed generation, wind energy, solar energy, protection coordination, short-circuit, wind plant, transient models