Commutating reactance

[NNG]

Please, I need clear explanation of this term : "commutating reactance". I've walked through some sources but could not fine a good one.
Thanks.

 

[jbartos]

Suggestion: Visit

http://udl.com/library/p5.html

In practice, the harmonic amplitude is affected by the commutating reactance Xc and delay angle _.

http://www.ro.feri.uni-mb.si/projekti/pdf/AC_motor_book.pdf

for: The rate of rise of current in thyristor 3 is limited by the commutating reactance, which is approximately equal to the subtransient reactance of the machine.
etc.

 

[NNG]

Here is my problem;
"The Customer spec calls for Harmonic Analysis of input current for operation at 50%, 75%, 100% output current at 60Hz and 5% commutating reactance".
With the first part of this item is not a problem, but the second part "5% commutating reactance" is odd!
How this term is practical? From my experience it is more theoretical explanation of the principle rectification regarding SCR front-end of the VFD’s than as a practical application.
If you used a value of the commutating reactance in Harmonic Study, please, share with me how.

 

[cuky2000]

There is a possibility to model the the SCR converter with a commutating reactance as a line inductor on the AC side.

Accordingly with manufacturers of commonly use 12-pulse converstion circuits, the expected input current distortion (ITHD) with 5% commutating reactance on the line side could be as follow:

- Voltage source Inverter........8%
- Current source Inverter.......15%

Check if the enclose site could help with ideas to model your circuit.

Good luck.

http://www.ee.uts.edu.au/~venkat/pe_html/ch05s4/ch05s4p1.htm#mathcad

 

[NNG]

Thanks, JBartos and cuky2000, for your references.
It was a good insight about this terminology.

 

[jbartos]

Suggestion: Visit

http://www.energythai.net/cepsi2000/T4006.pdf

for .5 P.U. commutating reactance

http://www.robicon.com/library/acrobat/vdfsurv.pdf

http://www.wempec.org/users/lipo/2000pub/Gautam_PESC'00

http://www.ro.feri.uni-mb.si/projekti/pdf/AC_motor_book.pdf.pdf

for: "The machine side converter normally operates in the inversion mode. Since the polarity of the machine voltage must be instantaneously positive as the current flows into the motor to commutate the bridge thyristors, the synchronous machine must operate at a sufficiently leading power factor to provide the voltseconds necessary to overcome the internal reactance opposing the transfer of
current from phase to phase (commutating reactance)."

 

[ICEMAN]

'Commutating reactance' is the European term for the AC line reactor applied to DC SCR drives.

ICEMAN

 

[jbartos]

Comment on the previous posting: It is good to know. The term is also defined in IEEE Std 100 "Dictionary" under several entries.