Closed Loop Identification for Multi-Area AGC Systems with Power Plant Time Delay Dynamics

Abstract

Alone with the automatic generation system (AGC) system modelling, a Subspace Model Identification (SMI) algorithm for the AGC system with power plant time delay dynamics is developed. The novel modelling framework utilizes the delayed time to identify dynamic models. These models are identified under closed-loop conditions and produce a joint representation that includes both the plant and controller models in state space form. Based on a typical transformation matrix T, an analytical separation of the plant model from the identified state space model can be achieved. The identified state space matrices of the simulation example showed negligible differences from the original system matrices up to a similarity transformation. Compared to previous research, this work (i) proposes a new modelling framework for identifying closed-loop systems, (ii) introduces a generic structure to represent the controller and (iii) explains how that the new framework gives rise to a simplified determination of the plant models. In contrast, the use of the conventional model approach renders the separation of the plant model a difficult task. Simulations for a typical two area AGC system with power plant time delay dynamics has shown that the approach is available for engineering application.