AC voltage transforming circuits in power systems

The paper deals with AC voltage transforming circuits applied in power systems. It includes a general description of AC power systems, single and three-phase AC converters, especially PWM AC line choppers and a description of their implementation in AC transmission or distribution systems. This includes a description of the topologies, the operation and test results of the voltage sag/swell compensators, quadrature phase shifters, power flow controllers, static VAr compensators and interfaces of renewable energy sources.