Power Factor Correction Capacitors

Power factor is known as the measure of how effectively a facility of a piece of equipment produces power to do certain work. Resistive loads like lighting and heating have higher power factors however the inductive loads including the AC induction motors do not use all of their energies or the power supplied to them because of which their power factor tends to be low.

Therefore, power factor correction has the purpose of improving the power factor along with its quality. It achieves this by reducing the load on the electrical distribution system, increasing the efficiency of energy, and minimizing electricity costs. It also helps in reducing the risk of any failure or instability of equipment.

How Do Power Factor Correction Capacitors Work?

As already mentioned, the power factor correction aims at improving the power factor as well as the power quality. Power factor correction can be achieved through the connection of capacitors that produce reactive energy against the energy absorbed by the loads, for example, the motors that are locally near the load. This will help improve the power factor from the point where the reactive sources are connected and also avoid the circulation of current in the network.

Determining the PCF required

For the selection of PCF equipment, it is important to follow these four steps by a person that has suitable skills for it.

Calculation of the Required Reactive Power

In the first step, you need to identify the required reactive power that needs to be installed, which is important for improving the power factor and reducing the apparent power.

Selection of the Compensation Mode

During installation, the location of a load capacitor can either be in the center, by sector, at load level, or it could be a combination of by sector or load level. Thus, we can say that the perfectly needed compensation is applied at a point of consumption and it is at the level that is needed at any point in time. But in practicality, the economic and technical factors affect the choice.

The location can be determined by:

• The overall objective
• The operating mode
• The foreseeable influence that the capacitors have on the network characteristics.
• And last but not least, the cost of installation.

Selection of the Compensation Type

• There are multiple types of compensation that can be adopted depending upon the requirements of performance and complexity of control.
• It can be fixed by a connection provided by a fixed-value capacitor bank.
• It can also be automatically provided by the connection of a different number of steps which allows the reactive energy to be adjusted to the required value.
• Or it could be dynamic that is needed for the compensation of greatly fluctuating loads.

Allowance for Operating Conditions and Harmonics

The life expectancy of capacitors can be determined to a great extent by the operating conditions. Therefore, the following parameters should be taken into consideration:

• Ambient temperature
• Maximum number of switching operations every year
• The required life expectancy
• Expected overcurrent is related to the voltage interferences that also include the maximum sustained overvoltage.
• Advantages of Power Factor correction
• Saves an extensive amount of money on electricity bills
• Reduces the size of installation to a great extent
• Installation of capacitors allows for voltage drops to be decreased upstream of the point where the PFC device is usually connecting hence preventing any sorts of overloads of the networks and decreasing harmonics.
• Increases the available power at the secondary of a transformer.