Harmonic Filters and Reactors

Harmonic filtering can improve equipment performance and reduce energy costs by eliminating unwanted harmonics in electrical systems created by non-linear loads.

When is harmonic filtering right for you? Are you experiencing…

1. Overheating of transformers and conductors
2. Generator instability
3. Capacitor failure
4. Nuisance tripping of fuses and circuit breakers
5. Damage to or failure of sensitive electronic equipment including drive failure
6. Telephone interference
7. Motors experiencing overheating, audible noise and reduced service life
8. High energy costs
9. Downtime and loss of production due to equipment instability.

How does harmonic filtering work?

Harmonic voltages and currents are caused by non-linear loads such as variable speed drives (VSD), uninterruptible power supplies (UPS), low energy lighting and switched mode power supplies in devices such as personal computers. Non-linear loads generate electrical harmonics by drawing current in abrupt short pulses, rather than in a smooth sinusoidal manner, introducing currents of additional frequencies which are reflected back into the system, distorting the AC waveform.

Harmonics increase the amount of power required by the system due to a reduction in power quality, contributing to a lower power factor and higher energy costs as a result of the reduced efficiency of the system.

Harmonic filtering acts to filter out the electrical harmonics in a system. This can reduce overheating of equipment, reduce nuisance tripping of circuit breakers and fuses and improve power quality contributing to reduced energy costs.

Types of harmonic filtering:

Line and load reactors – Reactors are used to provide current limiting. Reactors oppose rapid changes in current and hence limit spikes as a result of current pulses.

Passive harmonic filtering – Uses a combination of reactors and capacitors to filter out harmonic frequencies.

Active Harmonic Filtering – Provides harmonic compensation by being installed on the line side of the offending load (for example, VSD). They introduce current waveforms which cancel out undesired harmonic components.