MV design guide - Schneider Electric
MV design guide - Schneider Electric
MV design guide - Schneider Electric
You also want an ePaper? Increase the reach of your titles
YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.
Design rules<br />
Busbar calculation<br />
Mechanical busbar strength<br />
c By making the assumption that the ends of the bars are sealed, they<br />
are subjected to a bending moment whose resultant strain is:<br />
F1• l v<br />
η = •<br />
12 I<br />
with<br />
η : is the resultant strain,<br />
it must be less than the permissible strain<br />
for the bars this is:<br />
copper 1/4 hard: 1 200 daN/cm 2<br />
copper 1/2 hard: 2 300 daN/cm 2<br />
copper 4/4 hard: 3 000 daN/cm 2<br />
tin-plated alu: 1 200 daN/cm 2<br />
F1 : force between conductors daN<br />
l : distance between insulators<br />
in the same phase<br />
cm<br />
I/v : is the modulus of inertia<br />
between a bar or a set of bars cm 3<br />
(choose the value in the table on the following page)<br />
v : distance between the fibre that is neutral<br />
and the fibre with the highest strain (the furthest)<br />
phase 1 phase 2<br />
x<br />
c One bar per phase:<br />
b<br />
v<br />
h<br />
x'<br />
I =<br />
I<br />
v<br />
=<br />
b • h 3<br />
12<br />
b • h 2<br />
6<br />
c Two bars per phase:<br />
phase 1 phase 2<br />
v x<br />
b<br />
d<br />
h<br />
x'<br />
I = 2 ( b • h 3<br />
+ S • d 2 )<br />
12<br />
I<br />
v<br />
b • h<br />
2 ( 3<br />
+ S • d 2 )<br />
=<br />
12<br />
1.5 • h<br />
S : busbar cross section (in cm 2 )<br />
xx': perpendicular to the plane of vibration<br />
Check:<br />
η < η Bars Cu or Al (in daN/cm 2 )<br />
28 Merlin Gerin <strong>MV</strong> <strong>design</strong> <strong>guide</strong> <strong>Schneider</strong> <strong>Electric</strong>