An active harmonic filter (AHF) is a device that is used to mitigate harmonics in electrical power systems. Harmonics are unwanted frequencies that are generated by nonlinear loads, such as variable frequency drives (VFDs), electronic ballasts, and arc welders. These harmonics can cause a number of problems, including:

• Increased losses in transformers and other power equipment
• Voltage distortion
• Interference with sensitive electronic equipment
• Reduced power factor

AHFs work by injecting a signal that is equal and opposite to the harmonic current. This cancels out the harmonic current, which improves the power quality of the system. AHFs can be used to mitigate harmonics from a single load or from a group of loads.

There are two main types of AHFs:

   Passive harmonic filters: These filters use capacitors and inductors to cancel out harmonics. Passive harmonic filters are less expensive than active harmonic filters, but they are not as effective at mitigating harmonics.

   Active harmonic filters: These filters use power electronics to cancel out harmonics. Active harmonic filters are more expensive than passive harmonic filters, but they are more effective at mitigating harmonics.

AHFs can provide a number of benefits, including:

Improved power quality
Reduced losses in transformers and other power equipment
Reduced voltage distortion
Increased reliability of sensitive electronic equipment
Improved power factor

If you are experiencing problems with harmonics in your electrical power system, an AHF may be a good solution. However, it is important to consult with a qualified electrical engineer to determine if an AHF is the right solution for your needs.

Here are some of the factors to consider when choosing an AHF:

• The type of harmonics that need to be mitigated
• The size of the load that is generating the harmonics
• The desired level of power quality improvement
• The budget