Re: Constructing IEEE second benchmark for subsynchronous resonance using matpower

[Carlos E Murillo-Sanchez]

yangyang wrote: Thank you Carlos, I have also found it; the tap should be the ratio of per unit voltages instead of nominal voltages. But after changing the tap to 1, the power flow shows that all buses are 1 pu 0 degree, and it still differs from the load flow results in the Simulink example calculated using load flow block in Simulink's powergui, in which the angle at bus 4 is around -30 degree. I think it is because of the tap ratio and shift; the transformer has some resistance and inductance, and matpower manual says that the ratio has something to do with the impedence of the transformer, but I dont know how to calculate the tap ratio correctly based on the transformer impedence. Best Regards, Yang Yang � The transformer after the generator is most likely a delta-wye connection,� which would explain the generator's voltage lagging by 30 degrees the rest of the system.� Set the tap ratio to 0 or 1.0 (0 means no off-nominal tap ratio), and the angle shift parameter to 30 degrees (SHIFT column) and you'll get what you need. carlos.