Control Algorithms Of Digital Automatic Voltage Regulators For Synchronous Generators

Abstract

The main concepts of the application of digital controllers to a power system as automatic voltage regulators are presented in this paper. An experimental study using a physical model of a limited size power system has been performed and described. The synchronous generator model in this study was equipped with a microprocessor-based automatic voltage regulator. The control algorithm depends on a real proportional-plus integral-plus derivative scheme which is generally accepted as an efficient and reliable controller. The feedback signals to the controller are obtained as samples of the terminal voltage of the generator (as the main feedback signal) and the shaft speed (as the stabilizing signal). The second method was developed by applying an algorithm which computes on-line the weighting coefficients to the variances of the corresponding output variables. According to this strategy the weights are allowed to vary dynamically over all the range. A third scheme which depends on the same technique but assigns constant offset values to the weighting coefficients has been tested as well. The test results are presented in the paper. The experimental model and technique are also documented in the paper.