Automatic Voltage Regulator for Synchronous Generator

Abstract

Automatic Voltage Regulator (AVR) is necessary for all power stations producing electricity using synchronous generators (SGs) to ensure constant voltage for the grid connection. This final year report aims to design and implement an AVR based PIcharacteristics using Programmable Logic Controller (PLC) for the laboratory 1.5kVA salient pole Lab-volt SG. Primarily, a mathematical model for the SG is developed. Open circuit, short circuit and three-phase sudden short-circuit tests were realized for several tries in order to accurately identify the different parameters (Xd, X’d, X”d, Xq, T’d and T” , etc.) of the SG. Secondly, static self-excitation system is used where a part of the generated voltage is fedback to the exciter via a semi-controlled rectifier consisting of thyristors and diods. The PLC outputs a control signal to the implemented ramp-comparator strategy firing circuit in order to generate firing pulses to the thyristors. Particle Swarm Optimization (PSO) technique is developed in Matlab to tune the PI-gains. dLastly, the functionality of the AVR is tested for three different cases where small- and high-valued loads are connected at the SG terminals. The complete system response is shown in terms of voltage and current. Results are discussed validating the use of the AVR implemented.