Automatic HV capacitor banks up to 36 kV (2–4 steps)
Automatic high-voltage capacitor banks with insulation up to 36 kV and 2–4 steps. A controller switches the steps on and off according to the load and keeps the set power factor in a medium-voltage network. They are used at industrial substations, water treatment and desalination plants, and pumping stations with high-voltage motors.
- Steps
- usually 2–4, from 50 kVAr per step
- Insulation voltage
- up to 36 kV
- Switching
- vacuum or SF6 contactor, SF6 circuit breaker
- Pause between switch-ons
- 600 s; with fast discharge — less than 10 s
Price, availability and lead time on request. We help with analogue selection, customs clearance and delivery.
Description
Automatic banks are used where reactive power consumption in the medium-voltage network varies with time. The bank is divided into several steps, which the controller switches on and off according to the load, keeping the set power factor value. There are usually 2–4 steps, because more frequent switching of capacitors in a high-voltage network causes undesirable phenomena at the connection point. The capacitors are made to European and other international standards. The high-voltage product catalogue treats such banks alongside the compensation of motors and induction generators.
The bank is assembled in a metal cabinet and is fully configured for the project. The manufacturer carries out the design and calculation for a specific site. Step power starts from 50 kVAr, the total power is determined by the customer, and the maximum insulation voltage reaches 36 kV. Depending on the network voltage, single-phase or three-phase capacitors with internal fuses are used, with vacuum or SF6 contactors or SF6 circuit breakers. The APR fuses have a trip indicator, and the reactors limit the inrush current on switching. An MCX-type controller sets the time delays and controls step switching, and the control cabinet houses the reactive power controller, signalling and controls. For the inrush limiting reactors the catalogue gives a rated short-time current of 43 × In for 1 s (other kA per second values to order) and a frequency of 50/60 Hz.
The re-switching time of a step is a separate parameter for high voltage, because a capacitor must discharge before it is connected again. The standard pause between successive switch-ons is 600 s. If fast-discharge voltage transformers are fitted, the pause is reduced to less than 10 s, and the bank follows the load more quickly.
At the desalination plant in Oropesa del Mar (Spain, 2014) an automatic bank is in operation that compensates the no-load current of the transformer and part of the load; it is built on two three-phase capacitors. Typical sites are substations of industrial plants, water treatment and desalination plants, pumping stations with high-voltage motors, and oil refining.
Technical specifications
| Steps | usually 2–4, from 50 kVAr per step |
|---|---|
| Insulation voltage | up to 36 kV |
| Switching | vacuum or SF6 contactor, SF6 circuit breaker |
| Pause between switch-ons | 600 s; with fast discharge — less than 10 s |
| Controller | MCX / reactive power controller with signalling |
| Protection | APR fuses with indicator, inrush limiting reactors |
| Capacitors | single- or three-phase, with internal fuses |
| Enclosure | metal cabinet (example: IP23 for indoor use) |
Request a price and lead time
Automatic HV capacitor banks up to 36 kV (2–4 steps). We reply within one business day.
Or email sales@usk.ua or call 044 339-50-20.
Questions and answers
How many steps does an automatic HV capacitor bank have and what is the step power?
Usually 2–4 steps, to avoid undesirable phenomena from frequent switching in a high-voltage network. Step power starts from 50 kVAr and the total power is determined by the customer.
What pause is needed between repeated switch-ons of a step?
The standard pause between successive switch-ons is 600 s, because the capacitor has to discharge. With fast-discharge voltage transformers it is reduced to less than 10 s.
What is the maximum insulation voltage of the banks?
Up to 36 kV. As an example, 6.6 kV / 1638 kVAr banks for indoor installation with degree of protection IP23 have been supplied.
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