Reduced models and characteristic parameters of the synchronous machine obtained by a multi-time scale simplification

In this paper the authors propose a new way to express the currents and the voltages of a synchronous machine modeled with more than one damper winding on the d and q-axis. They use a model reduction based on the multi-time scale technique to obtain first-order equations which describe the subtransient, the different transients for each damper winding and the steady-state operation of the machine. Analytical expressions of the characteristic parameters (short-circuit or open-circuit time constants and reactances) and reduced operational reactances for each behavior of the machine are also given. The authors compute these expressions for real machines