Online Measurement Based Joint Parameter Estimation of Synchronous Generator and Exciter

Abstract

In this article, an online approach for joint parameter estimation of the exciter and Synchronous Generator (SG) is proposed. It only utilizes the Phasor Measurement Unit (PMU) based measurements, which can be obtained at the SG's terminal and does not require field measurements (as in brushless exciters). Compared to existing joint estimation approaches, the proposed work includes multiple aspects to put forward a pragmatic estimation framework. Firstly, the unobservable erroneous initial states are duly considered by utilizing the proposed Augmented Parameter Vector (APV). It is an essential feature in practical scenarios as an accurate representation of a dynamic system entails knowledge of true initial states and parameters. Secondly, suitable models of SG and exciter necessitate the inclusion of saturation characteristics, which is also considered in present work. Further, the estimation procedure is independent of multiple pre-tuned parameters, as such dependence may lead to tedious implementation and inaccurate estimates. Additionally, Wavelet denoising is used to improve the parameter estimation accuracy by pre-processing the noisy measurements prior to estimation. Real-Time Digital Simulator (RTDS) based simulation results, considering noise and measurement rate analogous to commercial synchrophasors, demonstrate the proposed approach's improved accuracy.