HVDC > HVDC Classic > HVDC technology > HVDC with CCC > CCC
The use of capacitor commutated converters has made possible a significant improvement of the traditional HVDC converter circuit.
In ABB's CCC concept, commutation capacitors are connected between the valve bridge and the converter transformers. This location has been found to be advantageous for several reasons. The capacitor stresses are much lower in this position than outside the converter transformer, as both the operating current and overcurrents are controlled by the valve bridge. (Read more about this!)
The CCC main circuit configuration
The capacitor overvoltage protection can thus be handled by a varistor of reasonable size. With a CCC there is no need to switch filter banks or shunt capacitors banks in and out to follow the reactive consumption when the active power is changed. This is the case for a conventional converter where it is normally necessary to subdivide the var supply in several breaker-switched banks.
The reactive power conditions for a typical conventional converter station and for a CCC.
Performance improvements
- Robust and resistant to disturbances
- Dynamic stability improved
- Reduced load rejection overvoltage