The function of a power factor correction capacitor in electrical systems is to improve the power factor of the system. The power factor is a measure of how effectively the electrical power is being utilized in an AC circuit. It is the ratio of real power (measured in watts) to apparent power (measured in volt-amperes or VA) and is expressed as a value between 0 and 1 or as a percentage.
A low power factor means that the reactive power (measured in volt-amperes reactive or VAR) is relatively high compared to the real power. Reactive power does not perform any useful work but is necessary to maintain the magnetic fields in inductive loads, such as motors, transformers, and fluorescent lights.
When the power factor is low, it leads to inefficiencies in the electrical system. The utility companies may charge consumers for both real power and reactive power, and a low power factor means that consumers have to pay for the unused reactive power, leading to higher electricity bills. Additionally, low power factor can lead to increased losses in the electrical distribution system, resulting in reduced overall efficiency.
By adding power factor correction capacitors to the system, the capacitors supply reactive power locally, offsetting some of the reactive power drawn from the utility. This reduces the total amount of reactive power needed from the utility, which, in turn, increases the overall power factor of the system. As a result, the system becomes more efficient, and consumers can reduce the amount of apparent power they draw from the utility, potentially leading to cost savings.
Power factor correction capacitors are commonly used in industrial and commercial electrical systems where inductive loads are prevalent. They are strategically installed to balance the reactive power and improve the power factor, thus optimizing the use of electrical power and reducing unnecessary energy losses.