Metal-Enclosed Harmonic Filters

TVAr (Standard and Point-on-Wave Switched)

To improve the quality of your power supply, Enspec Power provides harmonic filters that reduce nuisance circuit breaker tripping, stresses on electrical plants, and downtime - saving you time and money.

What are metal-enclosed harmonic filters?
What are metal-enclosed harmonic filters?
What are metal-enclosed harmonic filters?

What are metal-enclosed harmonic filters?

Harmonics are a distortion of the electrical AC supply and are typically generated by non-linear power electronic devices such as variable speed drives and inverters. Excessive harmonic distortion is problematic as it can cause equipment malfunction, leading to costly repairs and, in severe cases, grid connection issues, which results in costly downtime.

Harmonic filters are designed to either reduce troublesome harmonics to within defined parameters or dampen system resonances to prevent harmonic amplification.

harmonic filters

Better by design

Before we design a harmonic filter, we analyse a site’s harmonic profile, using data provided by the customer or obtained through our own precision measurement devices. We then use the extensive modeling experience of our power systems to design and simulate a bespoke harmonic solution. 

Unlike other traditional open-air (stack-rack) filter banks, Enspec harmonic filters protect your equipment and surroundings from environmental and animal impact. They are designed to withstand a variety of temperatures and weather conditions, making them suitable for both indoor and outdoor use.

The Enspec solution

When you factor in all costs - including engineering, integration, site preparation, installation, maintenance, and liability - a metal-enclosed filter bank design makes an ideal choice.

This is why Enspec manufacture a range of passive and/or active harmonic filter solutions:

  •  Passive harmonic filters – employ tuned LC circuits constructed from series-connected inductors and capacitors and offer a cost-effective solution to single lower order harmonic issues.
  • Damped filters – this passive technology incorporates added resistance: a tuned LCR circuit that provides a damped response across a broader range of harmonic frequencies.
  • Active harmonic filters – utilize power electronics to cancel unwanted harmonic frequencies by injecting anti-phase harmonic currents. These versatile real-time devices are programmable to target specific or multiple harmonic orders and may be used for other power quality issues such as voltage support, power factor correction, flicker compensation, and load balancing.
  • Hybrid filters – offer a combination of passive and active technologies where the passive section is used to filter low-order harmonics, and the active filter is targeted at higher-order harmonics only, minimizing the size, and cost of the overall solution.


Whichever of these solutions you choose, you can be sure your contained harmonic filters are designed to increase operational efficiency, improve energy efficiency, and improve equipment reliability - offering significant savings on your utility bill.

Add up the benefits for yourself

  • Free up the power capacity of the facility
  • Arc protection for safety of personnel and operation
  • Simpler engineering, project management installation than open-rack design
  • Improve the voltage profile and power factor
  • Reduce the apparent current and system loses
  • Increases the lifetime of transformers, motors, and others by eliminating harmonic currents
  • Provide reactive energy required by inductive loads
  • Avoid penalties due to poor power factor.
  • Reduces Green House Gas emissions
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For a range of applications

Enspec’s harmonic filters are designed to provide power factor compensation and harmonic mitigation for any environment, from low harmonics requiring fixed compensation to high harmonics that demand highly dynamic compensation.

  • Metal processing
  • Mining extraction and processing
  • Oil and gas extraction pumping and purification
  • Waste and clean water treatment
  • Food and Petrochemical processing
  • Plastic molding and extrusion
  • Cement and aggregate
  • Solar, wind, and hydropower renewables

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