STATIC SYNCHRONOUS COMPENSATOR (STATCOM)

·         The STATCOM (or SSC) is a shunt-connected reactive-power compensation device that is capable of generating and/ or absorbing reactive power and in which the output can be varied to control the specific parameters of an electric power system.

·         It is in general a solid-state switching converter capable of generating or absorbing independently controllable real and reactive power at its output terminals when it is fed from an energy source or energy-storage device at its input terminals.

·         Specifically, the STATCOM considered is a voltage-source converter that, from a given input of dc voltage, produces a set of 3-phase ac-output voltages, each in phase with and coupled to the corresponding ac system voltage through a relatively small reactance (which is provided by either an interface reactor or the leakage inductance of a coupling    transformer).

·         The dc voltage is provided by an energy-storage capacitor and a STATCOM can improve power-system performance in such areas as the following:

1. The dynamic voltage control in transmission and distribution systems;

2. The power-oscillation damping in power-transmission systems;

3. The transient stability;

4. The voltage flicker control; and 

5. The control of not only reactive power but also (if needed) active power in the connected line, requiring a dc energy source.

Advantages of STATCOM

 1.     It occupies a small footprint, for it replaces passive banks of circuit elements by compact electronic converters;

 2.     It offers modular, factory-built equipment, thereby reducing site work and commissioning time; and

 3.     It uses encapsulated electronic converters, thereby minimizing its environmental impact.