On the Identification of the Synchronous Machine Parameters Using Standstill DC Decay Test

Usually, the characteristic values of a synchronous machine are obtained from a short-circuit test at no-load. This test requires substantial equipment and is therefore expensive, it implies risks and it can not be always carried out for levels of voltage higher than 50% to 60% of nominal voltage. This DC decay test is an interesting alternative since only light equipment is needed. It delivers the characteristic values of synchronous machine for the two axes in function of the saturation state of the leakage paths. In general, the DC decay test is done for the two extreme positions of the rotor, dand qaxes. This contribution proposes a solution for a DC decay test extended for a random position of the rotor. This extension is important because, at standstill, it is almost impossible to fix the rotor of a large synchronous machine in a particular position.