There are a series of elements and materials, as in the case of LV equipment, for its HV operation that must accompany our HV capacitors for their correct operation and for that of our installation/network, as well as the rest of the equipment that compose it and that are in parallel operation with the capacitors that we want to put into service for the correction of the power factor (compensation of the consumption of Reactive Energy).
The choice of one type of equipment or another, as well as its configuration, will depend not only on the final cost of the equipment, but will also be marked by the mains voltage, as well as the loading regime of our installation.
There are two types of banks, depending upon the mode of connection. First is 3 phase single star connected, which is suitable, where voltage is preferably low, say up to 6,6 kV. Other is 3 phase double star connected bank assembled with minimum 6 Nos of single phase units, preferably for systems where voltage is higher, say 11 kV and above.
Direct three-phase connection.
They are formed by the connection of 1 to 4 three-phase capacitors in parallel. The internal connection of the three-phase capacitor of all the “elements” of which it is composed is in the form of a star.
The batteries may consist of the following components (depending on the characteristics of the installation):
- Metal enclosure.
- APR protection fuses.
- Switching contactor (opt.).
- Shock ballasts.
- Capacitors.
Logically, the existence of these elements depends on the client’s need and the network topology.
Generally speaking, the use of this type of battery is limited to insulation levels of 12 kV and powers from 50 to 1600 kvar / 2400 kvar, depending on the operating voltage if it is 6.6 kV or 11 kV.
Three-phase connection through a double star.
Formed by single-phase capacitors configured in two stars joined by a common neutral. The purpose of this connection is the possibility of incorporating an unbalance protection for the detection of possible internal defects in the capacitors due to the wear and tear and ageing of the equipment or defects that may occur from the electrical network.
Combined with capacitors with internal fuses, not only high safety, but also greater service continuity is achieved.
The number of capacitors in the double star depends on the mains voltage and the required battery power. In any case it must always be a multiple number of 3 and never less than 6 units.
The batteries may consist of the following components, depending on the characteristics of the installation:
- Metal enclosure.
- Gen. switch Automatic in SF6 of maneuvering (opt).
- Shock ballasts.
- Unbalance current transformer.
- Capacitors.
- Unbalance relay (optional).
Normally used when the configuration up to 12 kV max. voltage is not feasible due to power level (high power of Reactive Energy demanded) or insulation level (insulation voltages higher than 12 kV due to mains voltages of secondary transformers higher than 11 kV).
