Transmission line capacitance (charging) in VAR

[chuckd83]

I am looking at calculating line capacitance / line charging in VAR or VAR/mile for a HV line. Not charging current. I find plenty of sources on what it is, but not how to calculate it. I have the transmission line parameters such as R, X, and Y.

 

[davidbeach]

You need B. It's a geometry problem similar to solving for R. Most Power System Analysis texts should include a section on calculating line capacitance.

 

[chuckd83]

I believe I have that with Y which is the charging susceptance. It is given in siemens. How does this translate to VAR? Is it simply V(L-L)^2 * Y?

 

[wroggent]

Ichg = YVan

Qa = YVan^2

Where G = 0 and Y = j*2*Pi*f*Can

 

[HamburgerHelper]

ATP-EMTP has a calculator for line parameters if you don't want to do it by hand and it is free.

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If you can't explain it to a six year old, you don't understand it yourself.

 

[davidbeach]

Y is the inverse of Z (R + jX). The units may be the same as Y, but G + jB is very different than Y.

 

[cuky2000]

See the graph below from the IEEE Std