Active Harmonic Filters

Active Harmonic Filters

An Active Harmonic Filter (AHF) is a specialized power quality device used in electrical systems to mitigate and control harmonic distortion. Harmonics are undesirable electrical disturbances that can occur in power systems, primarily caused by non-linear loads such as variable frequency drives, rectifiers, and other electronic equipment. These harmonics can lead to a range of problems, including voltage distortion, increased losses, and interference with sensitive equipment.

Active Harmonic filter installation principle:

These harmonic filters, when connected in parallel to the mains supply, offers many benefits. Longer service life and reduced wear and tear due to its capacity to minimise temperature variations. Harmonic filter suppliers provide servicing and maintenance and also fulfil all the obligations of a contract with suppliers of energy regarding consumption. The power supply which is free of interference.

Listed below are its advantages:

1. Useful in places like the hospitals, Airports, shopping malls, etc. where the harmonic loads are generated.
2. High frequency of fuse blowing out and breakers tripping
3. Overheating and increased losses in the transformer and other distribution equipment
4. Malfunction of sensitive electronic equipment
5. Multiple instances of harmonic resonance, affecting the stability of the network
6. Production loss due to frequent equipment failure
7. Frequent failures in Power factor correction equipment like capacitors, reactors, and switching devices
8. Poor power factor (lagging or leading) resulting in penalties due to non-compliance and increased unit consumption
9. Abnormal electrical noise in the equipment

Commonly Used

Active Harmonic Filters (AHF) are commonly used in industrial settings, commercial buildings, data centers, and any facility with a high density of non-linear loads. They play a crucial role in maintaining power quality, minimizing energy losses, and preventing damage to sensitive equipment due to harmonic distortion.

Here's how an Active Harmonic Filter works and its key features:

Sensing and Monitoring:

- AHFs continuously monitor the voltage and current waveforms in the electrical system to detect harmonic distortion and its frequency components.

Real-time Control:

- Upon detecting harmonics, the AHF generates a compensating current with the same frequency but opposite phase to cancel out the unwanted harmonic currents. It does this in real-time, ensuring that the harmonic distortion is reduced or eliminated.

Modular Design:

- Many AHFs are designed in a modular fashion, allowing for scalability and flexibility in installation. You can add or remove filter modules as needed to address specific harmonic issues.

Customizable:

- AHFs can be programmed to target specific harmonic frequencies and provide selective harmonic compensation. This ensures that only the harmful harmonics are corrected, while essential harmonic components (e.g., 3rd or 5th harmonics) can be left untouched.

High Efficiency:

- AHFs are designed to be highly efficient, minimizing energy losses during operation. They typically have a power factor close to unity, improving overall system efficiency.

Fast Response:

- These filters have a fast response time, enabling them to adapt quickly to changes in the harmonic distortion levels in the electrical system.

Reduced Flicker:

- In addition to harmonic compensation, some AHFs can also mitigate voltage flicker caused by fluctuating loads like arc furnaces or welding machines.

Improved Power Quality:

- By reducing harmonic distortion, AHFs improve the power quality in the electrical system, reducing voltage distortion and ensuring that sensitive equipment operates reliably.

Compliance with Standards:

- AHFs are designed to meet international standards and guidelines for power quality, ensuring that the electrical system remains in compliance with regulations.