Low Voltage Capacitor Bank

The low voltage capacitor bank is an electrical device used for compensating low voltage power grids. It effectively improves the power factor of the power grid, enhances the stability of the power grid quality, and reduces line losses.

The low voltage capacitor bank consists of a control cabinet, capacitor, circuit breaker, fuse, current transformer, temperature protector, overvoltage protector, etc.



Rated Voltage 380V, 400V, 415V, etc.
Rated Frequency 50Hz/60Hz
Rated Capacity 10kvar~1200kvar
Capacitor Voltage 250VAC~690VAC
Capacitor Working Temperature -25℃~+55℃
Control Voltage AC220V, DC110V, etc.
Control Method Manual/automatic control
Overvoltage Protection 255V±5%
Overcurrent Protection Set according to the rated capacity
Short-circuit Protection 100kA
Insulation Resistance ≥100MΩ
Enclosure Protection Level IP30~IP54
Dimensions Customized according to customer requirements


  1. Long service life: The capacitor is made of high-quality materials, which have excellent durability and stability and can ensure stable operation for a long time.
  2. High power factor: The power factor of the capacitor is above 0.99, which can effectively improve the power factor of the power grid and reduce line losses.
  3. Safety and reliability: The capacitor has multiple protections, such as over-current protection, over-temperature protection, and overvoltage protection, which can ensure the safe and reliable operation of the equipment.
  4. Compact structure: The low voltage capacitor bank has a compact structure, a small footprint, and is easy to install and maintain.
  5. Easy to operate: The low-voltage capacitor bank is equipped with a sophisticated control system, which can realize automatic and manual control.

FAQ Guide

With the energy transition, good power quality is becoming increasingly important for utilities, industrial and commercial networks. The growth of renewable energy and the dominance of electronics in the industrial and consumer sectors have made the grid more susceptible and sensitive to harmonics, voltage variations, load imbalances, and low power factor disturbances.

These outages can result in reduced productivity, damage to equipment, financial loss, and penalties from utilities for not following grid codes. This article can help you understand the low-voltage capacitor bank, so let’s get started.

1. What is a low-voltage capacitor bank

Capacitor banks have been a reliable solution for reducing reactive power for decades. Installing capacitor banks for power factor correction is worthwhile if your goal is to increase electrical installation efficiency or reduce costs. Power factor correction increases grid capacity while preventing excessive cable losses and associated costs.

In addition, it reduces CO2  emissions. Not only can this improve your company’s operating profit, but it’s also good for the environment. Low-voltage automatic capacitor banks improve power factors in systems with variable energy demands and non-linear loads. Automatic capacitor banks are equipped with power factor controllers to adjust their automatic operation and monitoring functions, eliminating power factor charges in electricity bills and reducing losses in electrical equipment and wiring.

2. Advantages of low voltage capacitor bank

  • Eliminates charges generated due to low power factor.
  • Reduces losses within the system due to the Joule effect (heating).
  • Better voltage support and regulation.
  • Free up system capacity.
  • Prevents premature failure of equipment due to overheating due to undervoltage operation.
  • Dynamically adjust the power factor according to the load curve.

3. Characteristics of low voltage capacitor bank

  • The voltage range is from 240 to 1000 V.
  • Capacities from 30 to 1200 kvar.
  • Operates in ambient temperatures from -25 °C to 50 °C.
  • Long service life due to high-quality low-loss components and robust design for continuous operation at an operating temperature of 80 °C.
  • Single phase explosion-proof capacitors, 100% recyclable and UL listed (no potting).
  • Complete safety for the operator: the main switch is operated from the outside and a separate discharge resistor prevents unnecessary risks to the operator.
  • Easy installation and minimal maintenance: 100% field serviceable.

Low Voltage Capacitor Bank

4. Classification of capacitor banks

The following are several classifications of capacitor banks:

1) Relay control capacitor bank

Relay-controlled capacitor banks are the most common choice for reducing reactive power. These capacitor banks are suitable for various loads. Reaction times are slow, and there is always under-compensation or overcompensation. However, they are often the most cost-effective solution for small to medium installations.

2) Capacitor bank controlled by a silicon-controlled rectifier (SCR)

An SCR-controlled capacitor bank works the same as a relay-controlled capacitor bank. However, SCR control means reaction times are much better. This is ideal in applications where a large number of rapid load fluctuations occur, such as in installations with welding equipment, or frequently occur with large inductive loads of short duration (<1 minute), such as hydraulic presses. Static VAr generators are an alternative to SCR-controlled capacitor banks.

3) Motor static compensation

In some cases, reactive power is only used by large constant loads, such as electric motors in pumping stations that run 24/7. In these cases, the control of the capacitor bank is not strictly necessary and the capacitors can be connected directly in parallel with the motor.

5. Out of tune, what do you mean?

The impedance of a capacitor decreases with increasing frequency. This means that harmonic currents flow through the capacitor more easily than fundamental currents. This shortens the life of the capacitor. To reduce this effect, the capacitor bank is detuned. Add small coils to reduce high-frequency currents.

As the frequency increases, the coil has a higher impedance. If the capacitor bank is properly detuned, the chance of resonance is also reduced. Tuned capacitor banks are also possible. When adjusted correctly, they have a filtering effect. They are subsequently referred to as passive filters.

6. Is a traditional capacitor bank right for you?

Capacitor banks can only reduce inductive reactive power. If the load is capacitive, the capacitor bank will not do any improvement. Static var generators (SVG) are able to compensate for capacitive reactive power.


Go to Top