Nonlinear state space identification of a synchronous generator

A generating unit is a multivariable system and the linear and nonlinear model of the system is well defined in a state space structure. Subspace state space (4SID) identification method is suitable for the identification of such a system. This method is used in this paper to identify the parameters of a synchronous generator using online measurements following a small perturbation of the field voltage. The estimated parameters are then used to simulate a nonlinear state space structure of the system. Simulation results show that the proposed method is capable of estimating the physical parameters accurately. The results also show that the identified nonlinear model is valid at different operating conditions.