Harmonic Filter (THDi 5/8%)
RHF-5P and RHF-8P – highly efficient passive harmonic filters
The REVCON® harmonic filter RHF is passive filter, designed to reduce the harmonic distortion of a load fed by a 6-puls rectifier. This kind of load is very common in drive applications.
The REVCON RHF-5P/8P is a passive filter. It is not tuned to individual frequencies like an absorption circuit, but works like a bandstop filter, reducing all low harmonics up to the 200th significantly.
The following table shows the results of a 6-pulse rectifier with and without mitigation:
| Unchoked | Choked | Choked + RHF-8P | Choked + RHF-5P |
| >80% | ~40% | <8% | <5% |
The passive harmonic filter REVCON RHF- 5P and 8P is an effective, inexpensive and very efficient (>98.5%) action to reduce harmonic distortion of a drive system.
ADVANTAGES
- very compact size
- THDi below 5%
- output range 4kW to 630kW
- high efficiency
- user-friendly start-up, as no programming or settings are required
- maintenance free!
|
Application |
RHF-8P <8% THDi |
RHF-5P <5% THDi |
RHF-Hybrid ~1% THDi |
Active <5% THDi |
|
Vaiable Frequency Drives – VFD |
Yes |
Yes |
Yes |
Yes |
|
Water and wastewater treatment |
Yes |
Yes |
Yes |
Yes |
|
HVAC |
Yes |
Yes |
Yes |
Yes |
|
Pumps and Fans (VFD) |
Yes |
Yes |
Yes |
Yes |
|
Industrial/ Factory Process (VFD) |
Yes |
Yes |
Yes |
Yes |
|
DC charger |
Yes* |
Yes* |
Yes |
Yes |
|
Buildings |
Yes |
Yes |
Yes |
Yes |
|
Data Center (power supply) |
No |
No |
Yes |
Yes |
|
IEEE 519-2014 requirement |
Yes* |
Yes |
Yes |
Yes |
|
Marine |
Yes |
Yes |
No |
No |
|
IEEE 519-2014 specified application |
Yes |
Yes |
Yes |
Yes |
|
Electronically comutated / EC Motor |
No |
No |
Yes |
Yes |
|
Non symetrical Load |
No |
No |
No |
Yes |
|
Symetrical load multiple VFD |
Yes |
Yes |
Yes |
Yes |
|
Symetrical load multiple equimpment |
No |
No |
No |
Yes |
|
Displacement factor correction („pf“) |
No |
No |
No |
Yes |
|
Unbalance compensation |
No |
No |
No |
Yes |
Ideally all loads and sources have a pure sinusoidal current waveform. But unfortunately the true waveform of most equipment is very different. Nonlinear loads like for example the diode input bridge of a 6 pulse drive, are causing a distortion of the mains voltage. This distortion typically evaluated by the Total Harmonic distortion THD, evaluates frequencies from the 2nd up to the 40th harmonic. In a 50Hz Network this is the area between 100Hz and 2kHz.
The impact of the voltage distortion is diverse, and the most typical effect is overheat of transformer and PFC applications (Capacitor banks). Underestimated impacts of harmonic distortion is the significantly reduced lifetime expectation of electrical and mechanical equipment.
The Revcon Harmonic Filter (RHF) avoids the harmonic distortion of nonlinear loads and sources. The filter is not tuned to a specific frequency, but works like a bandwidth filter, reducing all frequencies up to the 50th harmonic. The RHF filter reduces the Total Harmonic Distortion of the current (THDi) to a level significantly below 5%. This is necessary to reach various standards, for e.g. IEEE 519-2014, who are getting more and more common.
Harmonic Distortion of Drives Part 1: Issues
Harmonic Distortion of Drives Part 2: Solutions
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