Method1... Use Locked Rotor Code
Method2... Use Starting / Running Current Factor
If the System Three Phase Short Circuit MVA is Known at the Point of Motor Connection... The Motor Starting Voltage Dip can be Estimated:
Less than 80% starting voltage is generally considered unacceptable. The required torque may be inadequate to reach full speed and the resulting voltage dip could affect other loads connected to the same circuit. An 80% motor terminal voltage will reduce the torque by 36%.
A realistic motor start analyis requires that the motor be modeled at a bus with the nominal voltage = motor nameplate voltage. This requires modeling the step down transformers and impedances.