Variable speed drives (VSD) and LED lighting are two products that can make a difference to your energy bill. But that’s just the beginning. Eaton’s ANZ commercial marketing manager, Sanjay Kallianpur, explains how to secure even bigger savings.

Three main load types dominate electricity use in commercial facilities. HVAC, lighting and plug loads (office device and computers) combine to represent almost 85% of all electric energy consumed by commercial customers. 

In addition to VSDs, installing Power factor correction (PFC) equipment provides the most common solution that provides real opportunities for savings. While new devices (such as VSDs) contribute great benefits such as optimising production processes, they also lead to higher levels of harmonics.

Harmonics are a concern because they can cause excessive heating in transformers and reduced torque in electric motors; increased heating and voltage stress in capacitors; and maloperation in electronics, switchgear and relays.

This can lead to premature aging of equipment which results in increased costs.  IEEE Std 519-2012 is a useful document for understanding harmonics and applying harmonic limits in power systems.

 One very basic distinction when discussing harmonics is whether the harmonics in question are voltage harmonics or current harmonics. According to IEEE 519, harmonic voltage distortion on power systems 69 kV and below is limited to 5.0% total harmonic distortion (THD) with each individual harmonic limited to 3%.

The goal of applying the harmonic limits specified in IEEE 519 is to prevent one customer from causing harmonic problems for another customer or for the utility.

There are several basic methods for reducing harmonic voltage and current distortion from non-linear distribution loads. One such method is active harmonic filtering.

Active harmonic filters work by monitoring the non-linear currents and electronically generating currents that match and cancel the destructive harmonic currents– so that a single active filter can be used for filtering VSDs of varying sizes. Unlike passive harmonic filters, these filters can provide harmonic mitigation under any load conditions up to their rated capacity.

Eaton have supplied the AFQm series in the Australian market, in wall-mount and rack-style floor-mount cabinets, to 400A harmonic correction capacity.

This latest active filter technology guarantees 5% THDi compliance for a set of non-linear loads and is an ideal solution for installations with a large amount of single-phase and three-phase loads generating harmonics, such as computers, UPS units, lights, lifting equipment and air-conditioning systems with variable speed drives.

The AFQm active harmonic filters are multi-function 3-in-1 units with multilevel technology that allows performing 3 different functions with one single unit, namely harmonic filtering, power factor correction and phase balancing.

With the proliferation of non-linear loads in today’s networks, active harmonic filter technology is key to solving harmonic problems and saving energy.

Sanjay Kallianpur is Eaton’s Commercial Marketing Manager for ANZ. With three decades of experience, Sanjay is a seasoned expert in Drives, Automation and Industrial Control Systems in the Electrical sector. Sanjay holds a degree in Electrical Engineering.

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