Steady-State Response of Inverter-Interfaced Distributed Generations During Transmission Network Faults

This paper evaluates the impact of the transmission network faults on the steady-state response of inverter-interfaced distributed generations (IIDGs), whose aim is to inject a fast fault current (FFC). Therefore, FFC-Voltage characteristics for the positive- and negative-sequence components are proposed that comply with requirements given by the network codes. A corresponding phasor-based IIDG model was tested in a 20kV network. Extensive numerical simulations of transmission network faults evaluate voltage symmetry and the operation of distance protection. The results show larger FFC injection by IIDGs in a weak transmission network, which is emphasized with a negative-sequence FFC-Voltage characteristic during asymmetrical phase-to-phase faults. Furthermore, IIDGs’ response increases the positive-sequence voltage magnitude during all fault types. Moreover, IIDGs’ response significantly affects distance protection operation at the receiving end of the transmission line; however, only in the cases of resistive faults.