Power Factor correction and detuned reactors

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mpeterson

New member
Hello, first post here at the forum. I tried searching for related threads but nothing came up, so here goes...

I am trouble-shooting the design of an existing power factor correction system. Medium voltage system (11kV) using a capacitors in series with detuned reactors, connected in wye. The reactor has shorted windings.

Calculations make sense on paper. Tuned to the 4.3 harmonic, all components selected to exceed system voltages and current. The problem I see is that the reactor is placed in series downstream of the capacitor. As far as I have researched (Google), every design puts the reactors upstream of the capacitor. With the system inductance and capacitance meeting a resonant frequency of the 4.3 harmonic , I can't see how this would be affected by placing the reactor upstream or downstream of the capacitor. But, with the reactor downstream, you are negating one of the uses of the reactor to limit in-rush current/transient switching voltage spikes.

Am I correct in thinking that the reactor should ALWAYS be placed upstream of the capacitor to limit these transients during switching operations? And, I am not sure if this is a cause of the shorted windings on the reactor, but it seemed to be inconsistent with every white paper I have read.
 

LMAO

Senior Member
Location
Texas
Hello, first post here at the forum. I tried searching for related threads but nothing came up, so here goes...

I am trouble-shooting the design of an existing power factor correction system. Medium voltage system (11kV) using a capacitors in series with detuned reactors, connected in wye. The reactor has shorted windings.

Calculations make sense on paper. Tuned to the 4.3 harmonic, all components selected to exceed system voltages and current. The problem I see is that the reactor is placed in series downstream of the capacitor. As far as I have researched (Google), every design puts the reactors upstream of the capacitor. With the system inductance and capacitance meeting a resonant frequency of the 4.3 harmonic , I can't see how this would be affected by placing the reactor upstream or downstream of the capacitor. But, with the reactor downstream, you are negating one of the uses of the reactor to limit in-rush current/transient switching voltage spikes.

Am I correct in thinking that the reactor should ALWAYS be placed upstream of the capacitor to limit these transients during switching operations? And, I am not sure if this is a cause of the shorted windings on the reactor, but it seemed to be inconsistent with every white paper I have read.

I use parallel LC circuits in my systems as well but for a different purpose (harmonics). You are right, reactors always come in first. I know it makes no difference in resonance frequency but not sure if the order of the two affects fault current.
 

Ingenieur

Senior Member
Location
Earth
4.3 harmonic?

the chokes limit cap-cap equalization currents when switched off-line
they introduce some Z
I just saw some
12" diameter
2" thick
plastic covered, wound flat ribbon conductor
2 mntg lugs
std option by cap mfgr
 
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