Listrik Kita is an official Schneider Electric distributor, providing original products with warranty for industrial and commercial electrical needs. One product that helps improve electrical system efficiency is the capacitor bank. This equipment helps correct the power factor by reducing the reactive power required from the electricity supply. To achieve the best results, however, the capacitor bank capacity and type must match the installation's actual conditions.
What Is Power Factor Correction?
Understanding Power Factor
Power factor is the ratio of active power used by electrical equipment to the apparent power supplied by the electrical network. It is commonly expressed as cos φ, with a value between 0 and 1.
In an AC electrical system, active power is measured in kilowatts (kW), reactive power in kilovolt-amperes reactive (kVAr), and apparent power in kilovolt-amperes (kVA). Active power performs useful work, while reactive power supports the magnetic fields required by equipment such as electric motors and transformers.
Why Is Power Factor Correction Important?
A low power factor means the system needs more current to deliver the same amount of active power. This can increase power losses in cables and equipment while reducing the available capacity of the electrical network.
Depending on the applicable electricity tariff and installation conditions, excessive reactive energy consumption may also result in additional charges. Power factor correction is therefore an important step toward improving electrical system efficiency.
What Does a Capacitor Bank Do?
How Does a Capacitor Bank Work?
A capacitor bank supplies reactive power locally, reducing the amount of reactive power drawn from the electrical network. With proper compensation, the installation's power factor can improve without changing the active power required by the equipment.
Benefits of Capacitor Banks for Industrial Applications
Installing a capacitor bank can help improve power factor, reduce current flowing through the network, lower electrical losses, and make better use of transformer and cable capacity. It may also help reduce additional charges related to reactive energy consumption when the compensation system is correctly sized.
The actual benefits depend on the load profile, network conditions, and the selected capacitor bank capacity.
How to Calculate Capacitor Bank Requirements
Calculating Based on Active Power and Power Factor
A common method is to calculate the required reactive power compensation using active power, the initial power factor, and the target power factor.
The formula is:
Qc = P × (tan φ₁ − tan φ₂)
Where:
- Qc = required capacitor bank capacity in kVAr
- P = active power in kW
- φ₁ = initial power factor angle
- φ₂ = target power factor angle
For example, an industrial installation has an active load of 600 kW, an initial power factor of 0.70, and a target power factor of 0.93. Using the formula, the estimated capacitor bank requirement is approximately 375 kVAr. The final capacity should be verified through site measurements and an assessment of the actual installation.
Using Electricity Consumption Data
Electricity bills can also help assess reactive power requirements. Data such as kVArh consumption and operating hours provide an overview of reactive energy usage over a specific period.
For more accurate results, this information should be combined with power factor measurements, load profiles, and actual operating conditions. A simple estimate should not be the only basis for selecting capacitor bank capacity.
Choosing the Right Capacitor Bank Compensation System
Fixed and Automatic Compensation
Fixed compensation uses capacitors with a relatively constant capacity. It is suitable for installations with stable loads and predictable reactive power requirements.
Automatic compensation uses a power factor controller to switch capacitor stages according to changing load conditions. This option is more suitable for industrial facilities where demand fluctuates as different motors and machines operate.
Understanding Harmonics Before Selecting a Capacitor Bank
How Do Harmonics Affect Electrical Systems?
Harmonics can be generated by power electronic equipment such as inverters, UPS systems, and variable speed drives. If they are not properly assessed, harmonics can affect capacitor bank performance and increase the risk of resonance within the electrical network.
Standard Capacitors and Harmonic Filters
Standard capacitors may be suitable for installations with acceptable harmonic levels. However, systems with higher harmonic distortion may require capacitors with appropriate ratings, detuned reactors, or harmonic filters.
The right configuration should be selected based on electrical measurements and technical analysis, rather than estimated harmonic percentages alone.
Tips for Choosing the Right Capacitor Bank
Before purchasing a capacitor bank, assess the active power, current power factor, target power factor, load variations, and harmonic conditions of the installation. Consider the protection system, switching requirements, available installation space, and maintenance needs.
Correct sizing is important to prevent overcompensation, which can cause the system to operate at a leading power factor. Consulting a qualified electrical professional can help ensure the compensation system meets the installation's operating requirements.
Improve your industrial electrical system's efficiency by choosing a capacitor bank that matches your installation requirements. As an official Schneider Electric distributor, Listrik Kita provides original products with warranty to support your business electrical needs. Visit Listrikkita.com to explore Schneider Electric capacitor bank products and consult the Listrik Kita team for help choosing the right solution for your application.
