Active Harmonic Filter overview

Active Harmonic Filter is connected in parallel in power grid, to detect the harmonic wave in power grid in real time, generate the reverse-phase compensation current through the converter, and dynamically filter the harmonic wave in power grid. The operation of AHF is unaffected by power grid structure and load type, and it will not produce harmonic oscillation with the system, thus perfectly realizing harmonic wave control of various loads.

Active Harmonic Filter can also realize dynamic reactive compensation, and control the capacitor switching, to improve the power factor of power grid. Meanwhile, AHF has the function of controlling the 3 phase load current unbalance, thus comprehensively solving various power quality problems with power grid.

Active Harmonic Filter module	Active Harmonic Filterack type APF panel

AHF Specification

Email us hanson@chinazddq.com,or click Active Harmonic Filter Datasheet to download details.

AHF principles

Active Harmoniic Filter(AHF) is connected in parallel with non-linear loads, and uses one set of current transformers (CT) to detect the load current. 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.

Active Harmonic Filter not only eliminates harmonic current from the load side, but it also mitigates harmonic voltage caused by harmonic currents. The AHF system can also improve power factor (PF) and correct load imbalances in the power system.

Active Harmonic FIlter Principle	Active Harmonic Filter Interface

AHF Features

■Multifunctional: Harmonic, reactive power and imbalance compensation

■High harmonic filtering rate: Up to 98%

■Excellent reactive compensation: High speed, Precise (-0.99≤PF≤0.99), Step-less, Bi-directional (capacitive and inductance) compensation

■Excellent imbalance correction: Both negative and zero sequence, mitigates neutral current

■Wide input voltage & frequency range, adapts to tough electrical environments

■Low thermal loss (≤3% of rated AHF A), efficiency ≥ 97%

■High stability: Infinite impedance to grid, avoids harmonic resonance problems

■Flexible application: Modular design, embedded in standard or customized cabinet

■Easy installation and maintenance: Plug-in installation for AHF module replacement and expansion

■Wide capacity range: 50A~600A for a single cabinet, up 10 cabinets in parallel

■Environmental adaptability: -10~50°C temperature, compatible with diesel generator

■Complete protection: Grid Over/Under voltage, AHF over current, over temperature, and more. All faults are recorded in the event log, which is convenient for failure analysis.

Application Fields

■Industrial installations with a set of non-linear loads representing more than 500kVA (variable-speed drives, UPSs, rectifiers, etc.)

■Installations requiring power-factor correction.

■Installations where voltage distortion must be reduced to avoid disturbing sensitive loads

■Installations where current distortion must be reduced to avoid overloads

Following are typical application industries of Active Harmonic Filter.