Minimizing maintenance costs in a skyscraper by mitigating harmonics

Challenges at the customer’s building

The central district cooling plant at the site has a significant amount of variable frequency drive loads. These VFDs are feeding the chillers, compressors, pumps, and other loads. The customer reported several issues which are commonly associated with poor power quality, such as burning of electronic cards, excessive heating of transformers, and replacement of VFDs.

Knowing that VFDs create significant harmonic current distortions, a power quality audit was performed initially on one of the several transformers by Distinguished Resources Company (DRC), Merus Power’s local distribution partner. The power quality audit showed that the Total Current Harmonic Distortion (THDi%) at the site was as high as 23%, clearly higher than allowable limits.

Our Merus® Solution

Based on the measurements, a power-quality solution was sized to bring the high current values below the desired limits. Merus® A2-series Active Harmonic Filter solution built in an IP21 cabinet was shipped from the factory. Merus Power’s local partner Distinguished Resources Company installed the Merus® Active Harmonic Filter parallel to the loads in a closed-loop configuration. Active Harmonic Filtering solution was configured during commissioning selectable harmonic mitigation mode to cancel 5th, 7th, 11th, and 13th harmonic currents.

Results after installation

Post-commissioning measurements proved that Merus® Active Harmonic Filter has brought the Total Harmonic Distortion Current (THDi%) under 5%, thus successfully helping to comply with IEEE-519 2014 power quality standards.

All individual harmonics which were exceeding the limits such as 5th, 7th, 11th, and 13th were also reduced to a minimum. Successful commissioning and compliance ensured that the electronic cards operate under ideal conditions with sinusoidal waveform, transformer losses are minimized, and overall reliability of the electrical equipment is maintained at desired levels.

Segment / Application

Commercial building – office skyscraper with Variable Frequency Drives (VFD)


Middle East

Power quality issue

  • High current harmonic distortion

Merus® Solution

Customer Benefits

  • Longer lifetime of electronic cards
  • Avoiding overheating of the transformer
  • Reduced maintenance costs
  • Longer lifetime of plant equipment
  • Compliance with IEEE519-2014 power quality standards

Do you have any questions?

Please contact one of our salespeople with questions and inquiries.

Markus Ovaskainen


+358 40 539 2145

Riku Kalliomaa

Head of Sales,
Regions & Channels

+358 50 3323 020

Jaakko Poutamo

Sales Manager,
Energy Storage, Europe

+358 50 918 0012

Mikko Zavertkin

Sales Manager,
Key Accounts & OEMs

+358 40 5908 858

Viktoria Mansikkala

Sales Manager,
Baltics & Eastern and Southern Europe

+358 44 9 735 737

Juhani Jaatinen

Senior Sales Manager,
DACH, Benelux, France,

+49 160 762 4909 (DE)

Venkatesh Ramachandra

Regional Sales Manager,
Middle East

+971 50 55 38 465
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