Power factor is a way of describing how efficiently electrical power is consumed. It refers to power in an alternating current (AC) electrical circuit, either for a single piece of equipment or all of the electrical equipment at a site. The power that is drawn from the network can be described as consisting of two parts –useful power and reactive power.
Useful power is the power that equipment needs to achieve the task at hand and it is measured in kW.
Reactive power is drawn in addition to useful power by a reactive load and is measured in kVAR. The consumption of reactive power does not contribute to achieving the task.
POOR POWER FACTOR HAS NEGATIVE IMPLICATIONS FOR BUSINESSES BECAUSE IT:
- Draws more current from the network – costing more to achieve the same tasks.
- Can incur a ‘poor power factor penalty’ from them supplier, sometimes called a ‘reactive power charge’.
- Reduces the effective capacity of the electrical supply, – the more reactive power that is carried, the less useful power can be carried.
- Causes losses at transformers and other devices, leading to inefficiency and unwanted heat gains.
- Can cause excessive voltage drops in the supply network.
- Can reduce the life expectancy of electrical equipment in extreme cases.
WHAT IS POWER FACTOR CORRECTION?
Power factor correction (PFC) techniques aim to bring the power factor closer to unity by reducing the effects of reactive power. In the great majority of cases, poor power factor is due to inductive loads which can be compensated by adding electrical devices called capacitors into the circuit.