A comparative study of two synchronous Machine modeling techniques for EMTP Simulation

Modeling and simulation of synchronous machines are traditionally based on the dq-axis model. An alternative method that uses direct phase-domain representation has been proposed over the past 30 years. One of the recent contributions , which is published as a letter in the June 2001 edition of Power Engineering Review , claims that the dq-axis model will give erroneous results in some cases, while the phase-domain model does not have such problems. This is a very bold claim. The purpose of this letter is to verify the conclusions of that Letter. Our simulation results indicate that both modeling methods produce very similar results. The letter´s conclusion might have resulted from a misuse of the PSCAD/EMTDC software.