Dynamic Parameter Identification Method of Synchronous Machine with Arbitrary Rotor Position Based on three-Phase Connected DC-Decay Tests

The three-phase short-circuit test is a common method for measuring transient parameters of large synchronous machines. The experimental process is complex and carries certain risks. Traditional stationary test methods can enhance the safety of parameter identification experiments; however, the required rotor pre-positioning for these experiments is difficult to implement in large synchronous machines. To address these issues, this paper proposes a synchronous machine parameter identification method based on a three-phase connection of the DC decay test at arbitrary rotor positions, grounded on the principle of signal input experiments. This method equivalently transforms the DC decay test of the three-phase connection at arbitrary positions into independent rotor d- and q-axis pre-positioned DC decay tests. Using the simulated annealing particle swarm optimization algorithm to fit the current response signal, the machine's dynamic parameters are calculated. The validity and accuracy of the proposed parameter identification method were verified through experiments on a 172 MV A synchronous machine. This method requires low testing equipment, involves fewer tests, and has simple data processing, making it safe and reliable.