An Adaptive Excitation System Controller in a Stochastic Environment

Abstract

Excitation of synchronous generators is utilized to control voltages in an electric power network through the control of reactive power. Excitation also has an important role in the improvement of the stability of synchronous machines in interconnected power systems. With the economic availability of dedicated computers and microprocessors in central power stations, new digital techniques and applications arise for the control of synchronous generators. Although the digital revolution has, perhaps, had the least impact on power engineering, this impact is increasing at an accelerated rate. The reason for this increased use of digital control is principally improvement in reliability of digital, solid-state devices in power system environments. Coupled with advances in digital hardware are advances in digital control theory. As an example, adaptive control theory developed 10-20 years ago for analog technology has been reexamined and reformulated for digital applications. With these facts in view, it is reasonable to conjecture that direct digital control of machines along with adaptive controllers can be implemented in the near future. This paper focuses on the design and performance of and adaptive excitation controller for synchronous generators. The utilization of self-tuning or adaptive controllers has been applied successfully in several industries [1-3]. Adaptive controllers usually require a parameter indentification stage. The self-tuning control problem is usually applied in the context of the problem of controlling a system with either constant or varying, but unknown, parameters. In this kind of regulator, a control law is obtained by combining a parameter estimator and a control strategy.