Hello, I have a PSS/E model that I would like to solve power flows for with MATPOWER, but it contains a three winding transformer. The PSS/E manual mentions that these devices are represented internally by three two-winding transformers and a fictitious neutral bus. To calculate the r and x for each of the transformers I have been using the equations:
r1 = 0.5 * (r12 + r31 - r23) x1 = 0.5 * (x12 + x31 - x23) r2 = 0.5 * (r12 + r23 - r31) x2 = 0.5 * (x12 + x23 - x31) r3 = 0.5 * (r23 + r31 - r12) x4 = 0.5 * (x23 + x31 - x12) However, this does result in negative values for certain windings. The magnetizing susceptance is given as a single value in the PSS/E file, so I have just been dividing it equally between the three branches. Does anyone have experience modelling three-winding transformers with MATPOWER, who might be able to tell me if I am missing anything or if I am on the right tracks? Regards, Richard
