Design of an automatic synchronisation system for an electrical generator to the grid

Abstract

Generators may be regarded as the workhorse of the power generating industry, supplying most of the real and reactive AC power. In the practical implementation of this project a small generator set has been used. However the performance should be similar to large scale commercial synchronous generators used in electrical power plants. The aim of this thesis is therefore to design an automatic synchronisation system for an electrical generator to the grid. This thesis introduces a new automatic synchroniser based on Space Vector Control theory. The device consists of a microcontroller and an inverter. The microcontroller is assigned to capture the grid and generator three-phase voltages. The frequency, phase and magnitude are calculated results derived from space vector theory. The microcontroller then provides the pulse width modulated signals for the gate drivers of the inverter. The inverter is used to provide outputs for the control of the mechanical input power to the prime mover, the generator field excitation, and instant of synchronism to the grid. Following synchronisation, the control module is further responsible for the control of real and reactive power supplied to the grid. The developed synchronisation unit is reliable, stable, and precise for monitoring, measuring and parallel operation of the synchronous generator.