Energy efficiency · Power quality

Harmonic filtering: clean power for modern electronic loads.

Variable speed drives, UPS systems, computers and LED drivers draw current in pulses and distort the supply. We measure the distortion and design filters that bring it back within limits.

Active harmonic filter cabinet with monitoring module

What are harmonics?

Harmonics are currents and voltages at multiples of the 50 Hz supply frequency. They are created by non-linear loads that draw current in short pulses instead of a smooth sine wave. As drives, UPS systems, IT equipment and LED lighting replace older loads, harmonic levels in commercial and industrial buildings rise.

Signs of a harmonics problem

  • Overheating transformers, cables and neutral conductors
  • Nuisance tripping and unexplained equipment faults
  • Failed or bulging power factor correction capacitors
  • Flickering lights and interference with sensitive electronics
  • Higher losses and less usable capacity

Active and passive filters

Passive filters use tuned inductor–capacitor circuits to absorb specific harmonic frequencies. They are robust and economical where the harmonic profile is stable.

Active harmonic filters measure the distortion in real time and inject an equal and opposite current, adapting as loads change and cancelling a wide range of harmonics. Many sites need a combination, coordinated with power factor correction.

Every project starts with a power quality study that measures distortion at the main incomer and key distribution boards. Designs aim to bring distortion within recognised limits such as IEEE 519, and results are checked after installation.

How we deliver

From measurement to verified savings.

Every measure follows the same process, and can be bought outright, leased or delivered under an Energy Savings Performance Contract with no upfront capital.

  1. Feasibility studyAnalysis of the facility's energy consumption, losses and savings potential.
  2. EngineerTechnical design and a bankable business case covering investment, savings and payback.
  3. FinancingSupport in securing financing, including the documentation lenders require.
  4. ImplementProcurement, installation and commissioning by our own engineers.
  5. VerifySavings measured to IPMVP on our EnMIS platform, reported monthly.
  6. MaintainPreventive maintenance for the full contract term, so that savings are sustained.
FAQ

Frequently asked questions

How do I know if my site has a harmonics problem?

Overheating, nuisance tripping, failed capacitors and flickering lights are common signs. A power quality study with a logging analyser at the incomer and key boards gives a definite answer.

Should we use an active or a passive filter?

Passive filters suit stable, predictable harmonic profiles. Active filters adapt to changing loads and cover a wide range of harmonics. The power quality study shows which fits, or whether you need both.

Do harmonics affect power factor correction?

Yes. Capacitors can resonate with the network at harmonic frequencies and fail early. We design power factor correction and harmonic filtering together.

Energy efficiency
Energy auditsWalk-through and investment-grade audits by an EPRA-licensed Category A audit firm. Voltage optimisationStabilise and reduce supply voltage to what equipment actually needs. Power factor correctionCut reactive power charges and free up transformer capacity. Variable frequency drivesMatch pump, fan and compressor speed to real demand. LED lighting retrofitEfficient LED lighting and controls, manufacturer-neutral. AC and refrigeration optimisationSmarter control of air conditioning, cold rooms and chillers.

Unexplained trips, heat or failures?

A power quality study will show whether harmonics are the cause and what it takes to fix them.

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