Inrush reactor inductance

[anksyete]

Can anyone help me about how to calculate the inductance value of inrush reactor which is used for inrush currents during medium voltage capacitor switching...

 

[magoo2]

You might find the following link to provide some useful results on the effects of different reactor sizing on inrush.

http://www.ece.mtu.edu/faculty/bamork/EE5223/mip99.pdf

 

[Marmite]

Inrush reactors are used to limit inrush currents, but also to detune the capacitor bank so that there is no possibility of resonance with the system. If you have a single capacitor bank, the inductance of the system upstream dominates the inrush current calculation, rather than the link inductance or any additional series inductance.
For a single Capacitor Bank
The inrush current depends on the fault level at the point of connection and the capacitor bank power in MVAr.

The closing peak current is given by:

I inrush= Icapacitor x?2 x ?(Scc/Q)

Scc: short circuit power of the source in
MVA at the connection point
Q: capacitor power rating in MVAr.

Regards
Marmite

 

[rbulsara]

The series reactance values are generally a low percentage of the capacitor reactance (at fundamental frequency), something like 3-5%, it should be able to carry the rated cap bank current in normal conditions without too much of a voltage drop, plus it needs to be checked for resonance.

Contact some cap bank manufacturers' application engineer, if you can. Given the parameters they will size it for you.

Also Google for the topic, you will find a few articles, just to give you an idea.

Rafiq Bulsara

http://www.srengineersct.com

 

[anksyete]

The article attached by magoo2 shows the effect of reactor inductance over inrush current. We are harmonic filter application partner of ABB and we almost use the reactance between 50-150uH. It depens on customer request. We can use 50uH and 150uH for the same system and I want to find how to calculate the exact value.