Merus® A2
Active Harmonic Filter

Merus® A2 is a scalable, versatile, and durable active harmonic filtering solution designed and manufactured in Finland using innovative Merus® Technology.

Customer benefits

  • Scalable and modular structure
  • Efficiency with quiet and economical high technology
  • Compliance with power quality standards and regulations (IEEE 519, G5/4, EN 50160, and others)
  • Energy savings and increased electric network capacity
  • Reliable plant operation and higher productivity at reduced maintenance costs
  • Longer lifetime of electrical and process equipment
  • Easy-to-use and smart HMI without complicated cryptic codes
  • Merus Power’s support and expertise throughout the device’s entire lifetime

Technical benefits

  • Fast response time – No over- or under-compensating
  • 3-level topology
    • Better efficiency and fewer power losses
    • Longer lifetime of power electronics
    • Smaller installation footprint
    • Lower noise levels
  • Modular scalability
    • Merus® A2-Active Harmonic Filters are connected in parallel with the loads to be compensated and you can install as many parallel modules as your system needs, without major technical limitations
    • Both open & closed-loop CT configurations
  • Compact design and ease of integration
    • Easy integration into electrical cabinets, VFDs, and capacitor cubicles
  • Merus® A2 is the backbone of Merus Power’s product portfolio and has been successfully helping customers tackle power quality problems worldwide.
  • Continuous research and development have made Merus® A2 an ultimate power quality solution for various industries and applications.
  • Our dedicated and talented R&D team ensures that Merus® A2 will continuously develop and remain the ultimate power quality solution in the future.


By adding Merus® A2-modules in parallel, higher harmonic compensation capacity can be achieved without any technical limitations. This offers flexibility when more loads are added to an electrical system.


Merus® A2 is one device capable of delivering multiple innovative solutions. Customizable functionality and several built-in operation modes make Merus® A2 an extremely versatile device.


Merus® A2 can operate in different demanding environments, even including harsh and heavy industrial ones without its performance and response time being negatively affected.

What can Merus® A2 do for you?

Active harmonic filtering

Merus® A2 senses the harmonic distortions created by non-linear loads in the network and provides an effective and real-time response to cancel them. Merus® A2 ensures guaranteed compliance with harmonic distortion limits specified in IEEE 519, G5/4, EN 50160, and other power quality standards and regulations. Merus® A2 can be installed to cancel harmonics of an individual large load or group of loads.

Dynamic reactive power compensation

Merus® A2 provides dynamic reactive power compensation, which is used for power factor correction, voltage variation, and flicker mitigation. This improves electrical efficiency in the electrical system and achieves money savings.

Load current balancing

Phase-to-phase connected equipment can burden only two of the three lines and create voltage unbalance between the phases. Merus® A2 offers dynamic load balancing that distributes the burdens more evenly between all three phases, which prevents overloading of the electrical system.

How does Merus® A2 work?

Merus® A2-Active Harmonic Filters operate similarly to noise-canceling headphones.

They measure the distorted current of the non-linear load and inject harmonic frequencies, but with an opposite phase angle. Canceling out harmonic currents reduces voltage harmonics and eliminates distortion at the point of common coupling.

They are connected in parallel with the loads to be compensated and measure the distorted current of the non-linear load then inject harmonic frequencies, but with an opposite phase angle. Canceling out harmonic currents reduces voltage harmonics and eliminates distortion at the point of common coupling. Only the fundamental frequency current component is left to be supplied from the power system.

Which of our solutions fits your needs best?

Merus® A2 MODULE

  • Small installation footprint
  • Standard: IP20 – Upgradable up to IP30
  • Possibility for partner/retailer to add value by cabinet integration
  • Easier logistics, local sourcing
  • Includes: Merus® A2 modules and Merus® HMI


  • Hides busbars, fuses, wiring
  • Standard: IP21 – Upgradable up to IP54
  • Keeps unwanted objects outside
  • Touch protection
  • Includes: Merus® A2 modules HMI integrated into electrical cabinets
  • The customer only needs to take care of the CTs that measure the current from the network or load side (depending on configuration)

Calculate your harmonic and unbalance needs!

We always strive to find new ways to help our clients achieve good power quality. In addition, we provide deep technological and engineering knowledge to provide the best customer experience possible. Good power quality is essential to minimize downtime and service and maximize production capability. Our expert engineers developed not one, but two smart calculators that help customers easily detect power quality issues.

Merus® Harmonic Calculator

Estimates the total harmonic current in any electrical system and calculates the need for active harmonic filtering to reach the desired compensation level.

Merus® Unbalance Calculator

Calculates the effect of load unbalance in your electrical system and estimates your need for active load balancing to reach the desired unbalance level.

Do you have any questions?

Please contact one of our salespeople with questions and inquiries.

Riku Kalliomaa

Head of Sales,
Regions & Channels

Jaakko Poutamo

Sales Manager,
Energy Storage, Europe

Mikko Zavertkin

Sales Manager,
Key Accounts & OEMs

Viktoria Mansikkala

Sales Manager,
Baltics & Eastern and Southern Europe

Juhani Jaatinen

Senior Sales Manager,
DACH, Benelux, France,

Venkatesh Ramachandra

Regional Sales Manager,
Middle East

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