May 27, 2014 - 11:56 PM
Please use correct data for your load flow studies. I would recommend you to use nominal pi model instead of tranmission lines in your case. Also, please calculate thevenin's equivalent for your sources. Try using Three Phase Voltage Source Model 2 with source impedance type Ideal i.e. (R=0). You would find more accurate data for 3 machine 9 bus system in the book Power System Dynamics and Stability by M.A. Pai and Peter Sauver in chapter 7 i.e. multimachine simulation.
Hope it helps.
Power Systems Simulation Engineer
Nayak Power Systems Pvt. Ltd.