Power Factor Correction

Power factor correction equipment monitors the power factor of the electrical system. It measures the phase difference between the voltage and current waveforms. A high power factor optimises the electrical system and makes better use of the components.

When the equipment detects a poor power factor, it calculates the level of reactive** power in the system. This power doesn't perform useful work but circulates between the source and the load, causing inefficiency.

**If you're unsure about what this is, we've added a short explanation further along.

If the power factor is lagging (below 1.0) due to an excess of reactive power, PFC equipment introduces capacitors into the system. Capacitors generate reactive power, effectively offsetting the excess power in the system. This process leads to a more balanced and efficient power factor.

As the capacitors release reactive power, the power factor of the system improves and gets closer to unity. This balancing of the power factor optimises the use of electrical power, reducing losses and enhancing efficiency.

The Difference Between Reactive, Apparent And Active Power

Active Power (Real Power):

• Active power (measured in watts, W) is the actual power that performs useful work in an electrical circuit. It is the power that powers devices and appliances.
• It represents the portion of the power that is converted into mechanical work, heat, or other useful forms of energy.
• Active power is the power that you are billed for by your utility company because it is the power that is genuinely consumed in the circuit.

Reactive Power:

• Reactive power (measured in volt-amperes reactive, VAR) is a component of apparent power that doesn't perform useful work but instead circulates between the source and the load.
• It arises due to the phase difference between the voltage and current in an alternating current (AC) circuit. In AC circuits, current and voltage are not always perfectly in phase.
• Reactive power is needed to establish and maintain the electromagnetic field in inductive loads (e.g., motors, transformers) and is returned to the source in capacitive loads.

Apparent Power:

• Apparent power (measured in volt-amperes, VA) is the combination of both active (real) power and reactive power.
• It represents the total power that flows through an electrical circuit and is analogous to the magnitude of the total power in the circuit.
• Apparent power can be thought of as the "hypotenuse" in a right-angled triangle, with active power as one side and reactive power as the other side.

In summary, active power (real power) is the useful power that performs work, while reactive power is the non-working power necessary to establish and maintain electromagnetic fields. Apparent power is the vector sum of active and reactive power and represents the total power flow in the circuit. The relationship between these concepts is described by the power factor, which is the ratio of active power to apparent power, and it quantifies the efficiency of electrical systems.

PFC equipment often operates automatically, continuously monitoring the power factor and adjusting the capacitors as needed to maintain a near-unity power factor.

By improving the power factor of an electrical network, PFC ensures that the electricity is used more efficiently, reducing energy consumption and operational costs for businesses.