A: The assumed flat solution does not enable the simulation of IBR models because this assumption does not agree with the equations governing the response of the IBR models. In addition, the IBR models are highly dependent on the voltage at their terminals, so the prefault conditions can have a significant impact on the IBR fault currents for a given fault. The simulation of IBR models in OneLiner requires prefault voltages to be calculated from a linear network solution or from a power flow solution.