Active Harmonic Filter
Ratings Available
AC Power
for Business-Critical Continuity™
30, 60, 100, 150, 300 A
Three phase
State-of-the-Art active filter, that dynamically cleans up Harmonics and improves Power Factor, for all types of electrical installations. It has dynamic control features and has no resonance effects, no reactive power circulation, no passive components.
What Are Harmonics?
Effect of Harmonics:
- Overheating of Generator, motor, transformer.
- Overvoltage conditions on supply system.
- Increased transformer losses (need to over-size)
- Nuisance tripping of circuit breakers
- Improper operation of microprocessor-based equipment
- Overheating and possible resonance with capacitors
- Re-injection of harmonic currents into the utility network.
- Neutral burnout.
- Insulation breakdown.
- Decreasing Distribution Capacity due to hot cables.
Harmonics are periodic, sinusoidal & integer multiples of fundamental frequency (50 or 60Hz), current or voltage components, present in nonsinusoidal waveform.
It distorts pure sinusoidal waveform and turns it to a non-sinusoidal waveform. Harmonics can only be measured by electronic measurement devices
Effect of Harmonics:
Harmonics are the by-products of Modern facilities and Electronic equipment. These are often called non-linear loads.
Examples of such loads are:
- Servers, Computers, PCs, Printers and other IT Equipment (Having Switch Mode Power Supplies)
- Controlled Rectifiers, Battery Chargers, Uninterrupted Power Supply (UPS) systems
- Phase controlled AC voltage regulators
- Compact Fluorescent Lamps, Fan regulators
- Traction Equipment
- Arc Furnaces or Induction Furnaces, Welding Machines
- Adjustable Speed AC and DC Variable speed motor drives
- PLC, DCS and SCADA systems (SMPS)
- Solid State Heater Controls
- HVDC sending and receiving end equipment.
OPERATING PRINCIPLE
Liebert AF3 latest technology to eliminate harmonic injected into the mains supply by non linear loads, as well supplies inductive power demanded by the load, so as to correct input power factor to near unity.
Current harmonic elimination is achieved by sensing load current & extracting harmonic current signal. This and the reactive current signal, together are used to generate a reference for the controlled current source connected at the PCC(point of common connection) of source and load.This results in mains supplying only real power for the load and reactive &harmonics being sourced from the AF3.This is carried out dynamically,so
that any change in the load pattern or its nature is immediately responded without any manual intervention.
In the following example first figure shows the recorded input current waveform of a six pulse thyristorised rectifier.
Bottom figure shows considerable improvement in the waveform due to AF3 connected in shunt.
One is with only harmonic correction and the other is with power factor & harmonic correction.
