ADF Harmonic Filter Selection Considerations


  • Losses

The lower the voltage, the lower the switching losses in an active filter. That is why a 480 Volt filter may be rated at 300 Amp of harmonic mitigation while the same size filter at 690 Volts would only be rated at 240 Amps.


  • Overloaded / Self-Regulating

Our active filters are a parallel device that cannot be overloaded. If, for some reason, the unit was undersized or the ambient thermal conditions were to rise to such a level as to cause potential damage, the controller on our filters would automatically throttle back the unit to maintain a safe operating temperature on the IGBTs.


  • Cooling Method

Our active filters are cooled by either air or water (liquid cooled). The air cooled version does not have a complex liquid to air heat exchanger or an additional air conditioner like some of the competitors. The liquid cooled units require a simple internal blower to pass the ambient air over the internal heat sinks with no air conditioner to fail. The liquid cooled units have their own internal heat exchanger and pump to eliminate the risk of contaminated liquids compromising the heat sink on the IGBTs. The complete liquid pumping system is designed for easy access and maintenance if required.

Liquid cooled Active Filters enable superior cooling of the IGBTs, the most critical component in the Active Filter. The water cooled active filter we utilize provides a 50% increase in current when compared to the same footprint of an air cooled unit. The power density of the installation is also improved as well as a reduced footprint


  • New or Existing installation

Being that our active filters are connected in parallel, they are ideal for retrofitting into existing installations. The existing power leads will not need to be cut and re-pulled which will greatly reduce downtime. If future expansion requires increased harmonic levels, then it is just a simple task to add more filters in parallel to mitigate the increased harmonics.


  • Ambient Conditions

Depending on where the unit(s) are installed, one may have to address the ambient conditions. If the area is too hot and dirty, such as a pipe heat treating facility, one may elect to install the unit(s) in a separate manufactured building or “house”. It may also be desirable, in that situation, to use liquid cooled units to reduce the requirement of cooled clean air.


  • Physical Footprint – How Much Cabinet Space is Required?

We have one of the smallest footprints in the active filter market to date and are looking at increasing the lead even further.


  • Modularity

As mentioned, a modular design of your Active Harmonic Filter enables you to adapt the filter to potential changes in your future power compensation needs. The modular design means that you can easily add additional filters to increase capacity. The largest installation we have to date incorporates nine of the large P300 modules connected in parallel.


  • Commissioning Software

Our web based user interface makes commissioning a breeze. This is a free feature on all of our drives and provides all of the tools to commission and view the operating parameters of the active filter. If you require the assistance of a start-up commissioning engineer for complex systems, we have technicians available nationally and internationally. Another advantage of the built in web based user interface is that it makes communicating information via the internet a breeze.


  • Smart Grid Functionality

Our active filters have a built in power quality meter that displays and transmits the harmonic levels and compensation current. Many facilities make use of this feature and use it to monitor power quality company wide through a web base communication protocol. An operator can then have an overview of the status of all connected filters and log them. This enables the possibility to log events that cause production disturbances, status monitoring of individual filters as well as remote control capability.


  • Voltage

Our standard Active Harmonic Filters are offered in a range of 208 up to 690 Volts. Our medium voltage packages typically range from 1 to 38 kV, though we do have some installations that address power quality issues on high voltage grids.

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