Power factor correction: what it is and why your site might need it?

Power factor describes the amount of real power transmitted along a transmission line relative to the total apparent power flowing in the line. In AC circuits, it is the ratio of real power (used to perform work) to apparent power (total power drawn from the source).

A perfect power factor is 1 (or 100%); this means that all power drawn from the grid is being used efficiently. Anything less means wasted energy and potentially higher costs.

If your site suffers from poor power factor, it can cause a range of issues on-site: increased electricity bills due to higher apparent power usage; with an overloaded system, your equipment, like transformers, cables, and switchgear, has to work harder; and you risk the potential of penalty charges from energy suppliers for inefficient power usage. With the overall system capacity reduced, your future equipment upgrades that you set to do could require more infrastructure, taking more time and money.

What is Power Factor Correction?

Accepted universally as one of the first steps recommended to reduce energy costs and improve energy efficiency. It works by "correcting" an inefficient electrical load of supply. Capacitors are automatically switched into the circuit to counteract the effects of an inductive load, which is produced by all machinery that uses motors.

These capacitors are often housed in PFC panels or capacitor banks and are installed in switchboards or distribution boards.

Specialist equipment isn't always needed to know something is wrong with your system. It is important to look out for the following: higher than usual electricity bills with no clear explanation; sites that use large inductive loads (e.g., compressors, motors, and welding gear); the energy supplier reports a low power factor; your equipment frequently trips or overheats.

What are the benefits?

When you add PFC equipment to a site, it helps to bring several long-term benefits: lower energy bills - by reducing wasted power, you are able to save on your energy bills as your system becomes more efficient; removal of "reactive power" charges (penalty for operating an inefficient electrical supply); reduction in kVa "Availability" and "Capacity" charges; reduction in kW/h losses; reduction in CO2 emissions; reduction in circuit currents; and improved utility.

Power factor correction is particularly useful for factories and workshops, commercial buildings, hospitals, larger offices, shopping centres and warehouses. When a site has large motor loads or a significant lighting footprint, it's definitely worth the power factor.

Power factor correction is a behind-the-scenes upgrade that can make a huge difference to a site's performance, efficiency, and bottom line. Whether you're designing a new panel, upgrading an old one, or helping a client reduce their energy bills, PFC should be part of the conversation.