Flexible AC transmission systems: Theory, control and simulation of the STATCOM and SSSC

Voltage Source Converter based Flexible AC Transmission Systems (VSC-FACTS) is the most recent approach in FACTS technology with the Static Synchronous Compensator (STATCOM) and the Static Synchronous Series Compensator (SSSC) as the key shunt and series compensation devices that open up new opportunities to control the power on transmission systems in order to enhance their utilization, increase power transfer capability, as well as improve voltage and transient stability. In order to perform an in-depth investigation, an exact model of a 24-pulse GTO converter, as the basic building block of VSC-FACTS, is developed which allows full investigation of all aspects of the STATCOM and SSSC operation by digital simulation.; The thesis addresses the development of the full detailed models of the STATCOM and SSSC and a novel control strategy to ensure the stability of the STATCOM under various power system conditions is proposed. The dynamic operation of the SSSC is investigated in great detail and a new control strategy is proposed to enhance the SSSC dynamic performance.