Noninvasive technique for determining parameter values from the sudden short-circuit test data of brushless alternators

The significant influence of the brushless exciter on the short-circuit response is discussed. A novel, noninvasive technique is proposed, which allows the parameters of the main machine to be deduced from a sudden short-circuit test on an unmodified brushless alternator. This is done by utilizing measurements taken from the stationary exciter field, but the results are processed in such a way that the effects of the exciter on the combined machine are excluded. If required, however, the "effective" parameters of an equivalent slip-ring machine, comprising the combination of the main machine and exciter, can also be extracted. It is suggested that this is a considerable improvement on existing techniques.