Areva HVX -F, Installation Operation & Maintenance

Page: 27 / 32

8.7 Maximum admissible number of breaking operations of the vacuum chambers
I
r
[A]
I
SC
[kA]
31,5 40 50
1250 – –
2500 – –
3150
n
30 000
10 000
1000
100
10
I
a
50
500
5000
I
SC
Bemessungs-Betriebsstrom I 1250 A, 2500 A, 3150 A
Ausschaltstrom
log
Ausschaltzahl
I
r
r
I
r
= Rated (normal) current [A]
I
sc
= Short-circuit breaking current [kA]
The diagram defines exclusively the
maximum admissible numbers of
breaking operations of the circuit-
breaker as a function of the rated
normal current
I
r
and of the short-cir-
cuit breaking current I
sc
. It indicates
when the vacuum interrupter cham-
bers need to be replaced.
The possible combinations depend
on the rated normal voltage:
For the data regarding the rated nor-
mal current
I
r
and the short-circuit
breaking current I
sc
, please refer to
the nameplate (Fig. 8.5).
1
2
Fig. 8.5
Data for rated normal current
I
r
(1) and short-circuit breaking current
I
sc
(2) on the na-
meplate
27
Number of breaking operations
n
Breaking current
log
I
a
Rated (normal) current I
r
1250 A, 2500 A, 3150 A