How to size an Active Harmonic Filter (AHF)

Active Harmonic filters (AHFs) play a vital role in reducing harmonics and enhancing power quality in electrical systems. Choosing the right size for an AHF is important for effective harmonic mitigation. This helps prevent both oversizing and undersizing of the equipment.

How to calculate the Active Power Filter size for a real project? Intone Power has gathered some references for you. We based these on our many years of experience in power quality solutions.

You usually need the following information:

• A one-line diagram of the system is essential.
• Indicate the locations and sizes of VFDs (Variable Frequency Drives) and Power Factor Correction Capacitors.
• A detailed equipment list is also helpful, particularly when combined with the one-line diagram.

VFD Information:

• Provide the horsepower or current rating for each VFD.
• Is each VFD using line reactors? If yes, please specify the impedance.

Active Harmonic Filter (AHF) Operation:

• Will the active filters operate when connected to a generator?

Additional Considerations:

• Are there any large soft-start loads downstream of the AHF?
• Please describe any local environmental conditions that may affect system performance.

Calculation Process for Sizing an Active Harmonic Filter (AHF)

Harmonic Analyzing

Begin by conducting a detailed harmonic analysis of the electrical system. This step involves identifying the dominant harmonic frequencies and their magnitudes. The results of this analysis provide essential data for determining the appropriate size of the AHF.

Load Assessment

Assess the total harmonic current distortion (THID) or total harmonic distortion (THD) of the load. THID/THD represents the percentage of harmonic currents relative to the fundamental current. This information is critical for estimating the required size of the AHF to effectively mitigate the harmonics.

Harmonic Current Compensation

Calculate the amount of harmonic current that needs to be compensated by the AHF. You can achieve this by multiplying the THID/THD by the rated load current. The result will give you the magnitude of harmonic currents that the AHF must offset.

AHF Sizing

Select an AHF with a current rating that can handle the calculated harmonic currents. Make sure to think about the AHF’s current capacity, voltage rating, and harmonic compensation abilities. This will help ensure it meets your system's specific needs.

Intone Power's AHF Solutions

Intone Power offers a wide range of Active Harmonic Filter (AHF) products designed to address various harmonic mitigation needs. AHF modules (rack and wall-mounted) range in size from 15A to 200A. You can customize the Cabinet solution from 50A to 750A. This makes them suitable for many different applications and load sizes.

Intone Power has the right AHF solution for you. You can use it to reduce harmonics in both small industrial setups and large commercial facilities.

Contact us for expert guidance:

Intone Power’s AHF solutions can help you reduce harmonics and ensure your electrical system operates reliably.

For more information on how our Active Harmonic Filter and Static Var Generator can help compensate reactive power and improve power quality: sales@intonepower.com