even harmonics
even harmonics
(OP)
Trying to design a PFC bank for medium voltage application, 10kV system voltage and measuring the system harmonics, I found out that the even number harmonics are really big: 4,65% the second order current harmonic, 2% the 4-th and 1.25% 6-th harmonic. Also pretty big was the third and triplen harmonics (third harmonic level 3.7%)As the desired sollution was to implement a passive filter with three branches for 5-th, 7-th and 11-th harmonics - which are the biggest), the existence of the 4-th and 6-th harmonics rises difficult problems regarding the amplification of these harmonics in the presence of the filter. Can anyone explain which is the possible cause of these un-characteristic harmonics ? The plant is packed with power SCR converters(6 and 12 pulses) and VFD drives, supplied on low voltage.
Thank you!
Pafi
Thank you!
Pafi






RE: even harmonics
Some firing schemes for reducing apparant power during phase control also give rise to even harmonics.
RE: even harmonics
The half-wave rectifier is causing even harmonics. This is in agreement with the above posting.
It is good to refresh the Fourier Series or Fourier Transform Analysis for the elementary issues of harmonics.
RE: even harmonics
RE: even harmonics
concentrate on nature of load alos.
RE: even harmonics
RE: even harmonics
http://ercap.org/licencing/connectioncode.htm
http://www.nrel.gov/docs/fy03osti/32864.pdf
for total even harmonic distortion TED