Ensuring reliable operation in a water treatment plant

Challenges in the customer’s water treatment plant

A water treatment plant in Galati, Romania was suffering from harmonic currents due to the use of 6-pulse variable frequency drives (VFDs) to control the plant’s processes. VFDs produce an output that is not fully sinusoidal, which can result in high harmonics. Harmonics caused by VFDs can disrupt or stop the operation of sensitive equipment. Measurements revealed that the 5th and 7th components produced the most significant harmonic distortion in the plant. The plant suffered from poor power quality and had to fulfill the local harmonic distortion level standards and regulations.

Our Merus® Solution

The chosen solution was four Merus® A2 – 200A Active Harmonic Filter modules installed in parallel with the load, which brought the total compensation capacity up to 800 A. The Merus® A2 modules were installed with help of a local integrator. Merus® A2-series Active Harmonic Filters have a response time of fewer than 100 microseconds and they can mitigate harmonics up to 50th order, ensuring reliable operation.

Results after installation

After installing and commissioning Merus® Active Harmonic Filters, harmonics got mitigated to acceptable limits. The lowest THD was achieved by splitting the filtering capacity between the 5th and the 7th harmonic component. THD(i) before commissioning the active harmonic filters was approximately 32.6%. After commissioning it was reduced to 4.8%.

The water treatment plant enjoys reduced downtime, lower maintenance costs, energy savings, and longer lifetime of sensitive plant equipment due to improved power quality.

Segment / Application

Water treatment plant with 6-pulse Variable Frequency Drives (VFD)


Galati, Romania

Power quality issue

  • Harmonic distortion

Merus® Solution

Customer Benefits

  • Reduced maintenance costs
  • Reduced downtime
  • Energy savings
  • Longer lifetime of water treatment plant
  • Longer lifetime of sensitive equipment
  • Mitigated harmonic distortion

Do you have any questions?

Please contact one of our salespeople with questions and inquiries.

Markus Ovaskainen


+358 40 539 2145 markus.ovaskainen@meruspower.com

Riku Kalliomaa

Head of Sales,
Regions & Channels

+358 50 3323 020 riku.kalliomaa@meruspower.com

Jaakko Poutamo

Sales Manager,
Energy Storage, Europe

+358 50 918 0012 jaakko.poutamo@meruspower.com

Mikko Zavertkin

Sales Manager,
Key Accounts & OEMs

+358 40 5908 858 mikko.zavertkin@meruspower.com

Viktoria Mansikkala

Sales Manager,
Baltics & Eastern and Southern Europe

+358 44 9 735 737 viktoria.mansikkala@meruspower.com

Juhani Jaatinen

Senior Sales Manager,
DACH, Benelux, France,

+49 160 762 4909 (DE) juhani.jaatinen@meruspower.com

Venkatesh Ramachandra

Regional Sales Manager,
Middle East

+971 50 55 38 465 venkatesh.ramachandra@meruspower.com
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