Harmonic Filter operating characteristics
Harmonic Filter operating characteristics
(OP)
We have an harmonic filer in our facility that is no longer in service and has not been for a while. All the origonal personel involved with this filter are long gone and there is nobody or no information left behind to explain why the filter was origonally installed.
I am curious about the origonal intent of this filter and what its specific purpose was. Is it possible to tell from just the electrical paramaters of this filter design what the purpose of the filter is? Is it possilbe to tell what frequencies or harmonics it was designed to pass or trap?
The filer is connected on a 4.16kV 3 phase system. The filter on each of the three phases has a 472 uH/phase inductor in parallel with a 3.2 ohm/phase resistor with this parallel combination then being in series with a 92uF/phase capacitor.
Is it possible from this information to come up with the intended filter design paramaters? Is there an equation that can be used?






RE: Harmonic Filter operating characteristics
RE: Harmonic Filter operating characteristics
Would you be so kind as to point me in the right direction for calculating this design operation based off of these paramaters?
RE: Harmonic Filter operating characteristics
Neil
RE: Harmonic Filter operating characteristics
The caps are wye connected
RE: Harmonic Filter operating characteristics
f = 1/2*pi*(sqrt L*C)
RE: Harmonic Filter operating characteristics
Any idea why this resonant frequency of 746Hz would be of particular importance in an industrial facility.
Most of our non-linear loads consist of 6-pulse drives however we do have several power factor caps at our large motors. Would this frequency be an attempt to block or trap the 13th harmonic created from these 6 pulse drives?
RE: Harmonic Filter operating characteristics
Other than that, maybe the 13th is causing some specific interference problem. And this filter is trying to address that.
Neil
RE: Harmonic Filter operating characteristics
This filter is located on a downstream bus in close proximity to our main plant incoming bus. In this located will it filter these frequencies for the entire plant or only for equipment downstream of the bus the filter is located on?
Does the filter simply trap these third harmonic frequncies not allowing them be seen by other equipment.
Will the caps in this filter provide power factor correction for the rest of the plant.
I also assume that the point of the resistors in this filter is to not allow the filter to self resonate when the AC source is removed thus dumping all resonating energy across these resistors?
RE: Harmonic Filter operating characteristics
In your case, it sounds as though the next up stream L is the transformer. so all harmonics from the transformer to all loads are seen by the trap. Perhaps the trap is tuned to interact with down stream reactors and transformers and the net is a different tuning frequency. Find the largest 2 or 3 VFD loads and find out how much L is in fron of them then use that in conjunction with the trap reactor to calculate the new tuning frequency.
Neil
RE: Harmonic Filter operating characteristics
RE: Harmonic Filter operating characteristics
Neil
RE: Harmonic Filter operating characteristics