Cable generated kVAr's in ETAP

[lz5pl]

I try modelling 20 kV grid of windfarm using ETAP. One of known problems is that when all generators are off grid generates back to National Grid reactive power which must be compensated.
My model consists of about 24 km 20 kV cables, 3x185 sq.mm. Rule of thumb is that such cable generates about 1 A per km. But when I switch off all generators and start Load Flow I cannot see any currents back to National Grid. NG is set in "swing" mode. Probably I miss something, but I am still not very experienced in ETAP . Any suggestions will be wellcomed.
(Actually I can easily calculate this reactive power and necessary compensation by hand, but I am curious if I have a mistake or the program simply doesn't consider these reactive currents).

------------------------
It may be like this in theory and practice, but in real life it is completely different.
The favourite sentence of my army sergeant

 

[exciting]

Are you sure the model of your cable includes shunt capacity? I know SKM Powertools default MV cable models don't include them, though I can't speak for ETAP.

If you cannot modify it yourself, maybe add a pi impedance with the (hand calculated) values.

 

[dpc]

I'm not sure what ETAP's cable model looks like. I'd suggest constructing a very simple system with one long cable and one source. If you don't see any kVAR flow when running a power flow, the cable model may not be accounting for the shunt capacitance.

You should be able to look at the data and see if there are any capacitance terms.

As suggested, you may have to add some capacitors to the model along the way.

David Castor

http://www.cvoes.com

 

[lz5pl]

Thank you all for suggestions.
We here have a saying: Morning is clever than the evening. Now I checked again "Impedance" window and found that in the library parameter Y for this cable is set to "0". I calculated and entered suceptance and now everything is OK.

------------------------
It may be like this in theory and practice, but in real life it is completely different.
The favourite sentence of my army sergeant