A SVC (Static Var Compensator) is a high voltage system that controls dynamically the network voltage at its coupling point. Its main task is to keep the network voltage constantly at a set reference value.

Some other control features are:

The design and layout of a SVC system is always tailored to the specific project requirements.

 

The picture above shows the principle topology of a SVC coupled to the network via a high voltage transformer. On the secondary side there is an arrangement of usually 2 or more parallel branches. The following 3 principle branch types are available:

TCR : T hyristor C ontrolled R eactor for linear injection of inductive reactive power

TSC : T hyristor S witched C apacitor for stepwise injection of inductive reactive power

Filter: Tuned filter capacitor for fixed capacitive reactive power and harmonic filtering

Number and type of selected branches depend on the specific application and are project tailored. The most simple configuration is a TCR/Filter combination.

The reactive power is changed by switching or controlling these reactive power elements connected to the secondary side of the transformer. Thyristor valves act as extremely fast switches. Each capacitor bank is switched ON and OFF by thyristor valves (TSC). Reactors can be either switched (TSR) or controlled (TCR) by means of thyristor valves.

The system ratings of SVCs are:

Typical voltage levels: approx. 33 < kV < 800

Typical overall ratings: approx. 40 < MVAr < 800

The selected references offer detailed information about Siemens´ activities in interesting projects worldwide from 1993 until today:

Please use the following link for a overview of our references.