Reactive compensation. Problems and concepts of static compensator control

The paper is in three parts. In the first part, general control problems are discussed which arise whenever static compensation is used, irrespective of the applications concept chosen, e.g. variation of the closed-loop response, effects of resonances in the network impedance, maintenance of a certain reserve of power in the SVS (static VAR system) to cover faults. In the second part, a comparison is made between systems with fixed capacitor banks and systems with thyristor-switched capacitors. Here the main point is the differences from the point of view of the control techniques applied. The third part contains a summary of the structure and functional units needed for voltage control, and also the various options for VAR regulation and SVS control of switchable compensators