ABSTRACT
Power quality problems include voltage sags and swells, high-frequency line-to-line surges, steep wave fronts, or spikes caused by switching of loads, harmonic distortions, and outright interruptions, which may extend over prolonged periods. The concept of flexible AC transmission systems (FACTS) was developed by EPRI and many FACTS operating systems are already implemented. Advances in recent years in power electronics, software, microcomputers, and fiber-optic transmitters that permit signals to be sent to and fro from high-voltage levels make possible the design and use of fast FACTS controllers. The use of electronic devices in processes, industry, and the home has created an entirely new demand for power quality that the energy providers must meet. A solid-state synchronous voltage source (SS) can be described as analogous to a synchronous machine. The gating signals for the GTOs are generated by the internal converter control in response to the demand for reactive power and or real power reference signals.
