Robust Unknown Input Reconstruction Observer for Hierarchical Parameter Estimation of Synchronous Generator and Brushless Excitation System

In this article, we cope with the parameter estimation (PE) of the synchronous generator (SG) and the excitation systems. The field winding signals are not available for accurate measurement in the proposed strategy. To this end, a robust unknown input reconstruction observer is exploited to determine both SG unknown inputs, including the mechanical torque and field voltage, under disturbances influence. Moreover, the gathered data from one of the SG identification tests, such as a power system stabilizer-based method, are deployed for PE of the SG and excitation system hierarchically in the way that the excitation system identification is conducted after reconstructing the field voltage and current. The recommended approach is applied to a 150 MW gas unit, and the comparisons of the simulation and measurement data during validation tests demonstrate the high accuracy of the resultant parameters.