Power Converter Characteristics
||F3 - F5 - F7 - F11 - F13 - F18
Power Converter Architecture
A static VAR compensator (var is defined as volt ampere reactive) is a set of electrical devices for providing fast-acting reactive power on high-voltage electricity transmission networks. SVCs are part of the Flexible AC transmission system device family, regulating voltage, power factor, harmonics and stabilising the system. Unlike a synchronous condenser which is a rotating electrical machine, a static VAR compensator has no significant moving parts (other than internal switchgear). Prior to the invention of the SVC, power factor compensation was the preserve of large rotating machines such as synchronous condensers or switched capacitor banks.
SVC is composed of two components.
- TCR (Thyristor Controlled Reactor) :
A TCR is a reactance connected in series with a bidirectional thyristor valve. The thyristor valve is phase-controlled, which allows the value of delivered reactive power to be adjusted to meet varying system conditions. Thyristor-controlled reactors are used for limiting voltage rises and reactive power compensation.
In parallel with series connected reactance and thyristor valve, there may also be a capacitor bank.
- Harmonic Filters :
They are composed of capacitors and coil tune for different harmonics. For LHC, we have 6 filters for harmonics 3, 5, 7, 11, 13 and 18. The LHC filters take 24MVar from network
||-24 to +24 MVAR
2 Motor Pump 1.5kW
Demineralized second circuit water
Second circuit water cooled
Control & Regulation Part
SVC installed in LHC:
Production Contract & Contract History
There are four SVCs which were supplied by GEC Alsthom to support the operation of the LEP Particle Accelerator at CERN.
They are all rated at 24.4 MVAr and are situated at various access points around the LHC ring designated PA2, PA4, PA6 and PA8.
The equipment sited at PA2 and 6 is the oldest and was supplied Circa 1987. The other two at PA4 and 8 are more modern and were supplied Circa 1992.