Hi. As part of my research work, I am investigating the synchronous machine stability at low speeds. I connected the SI fundamental simulink blockset machine with exciter and speed input to a load. Before I simulating I have tried to carry out a load flow to get steady state using the powergui with no success! I keep getting the error, Undefined function or variable "xa" in the matlab window. Unfortunately I cant get past this error and its delaying my research considerably. Can anyone give me direction on this please…..Thanks.