Active Harmonic Filter

What is Active Harmonic Filter

1. Harmonics come from the nonlinear load. Active Harmonic filters also called harmonic correction unit are power electronic devices connected in parallel with the load to be compensated.
2. They act like a noise cancellation system and inject equal and opposite frequencies to mitigate harmonics.
3. The filters can also provide additional current to correct the power factor.
4. So, what’s left coming from the source flowing back to the utility is only a nice, clean current that is in phase.

Working Principle of AHF

1. Active Harmonic Filter is connected in parallel with non-linear loads, and uses one set of current transformers (CT) to detect the load current.
2. It calculates each order harmonic current, and then generates a compensating current with the same amplitude but opposite phase angles to the detected harmonic current, which cancels out the original load harmonics.
3. The AHF not only eliminates harmonic current from the load side, but it also mitigates harmonic voltage caused by harmonic currents.
4. The AHF system can also improve power factor (PF) and correct load imbalances in the power system

Advantage of using AHF

1. Wide Range of Harmonic Selection: Selec AHFs cancel all the odd harmonics up to 51st order. Further, these harmonics are individually selectable without any limit on the number of harmonics selections at a time.
2. Integrated Best in Class HMI: Selec AHFs have integrated 4.3-inch Touch screen HMI display to visualize/set the AHF and plant parameters. User can observe real time three phase voltages and current waveform.
3. Optimum Design: Light in weight, compact in size, quieter in operation while delivering best in class performance.

Active Harmonic Filter

Features of AHF

 Harmonic Compensation up to 51st harmonic (Individual selectable)
 Capacitive (Leading) & Inductive (Lagging) reactive power mitigation
 Compensates current unbalance created by the load
 Ensures the Total Harmonic Distortion of grid Voltage <3%*
 IGBT parallelling technology

Key Benefits

 Close to pure sinusoidal plant current
 Stay protected from upcoming harmonic penalties by electrical distribution companies
 Reduced plant down times from the nuisance tripping of plant equipment due to harmonics
 Improved plant equipment life with reduced maintenance cost.