Functions
144
7SS52 V4 Manual
C53000-G1176-C182-1
• Group alarms (selective):
“Id-sup BZ M“ (FNo. 10415/CU),
“Id-sup BZ L1 M“ (FNo. 10416/CU),
“Id-sup BZ L2 M“ (FNo. 10417/CU),
“Id-sup BZ L3 M“ (FNo. 10418/CU),
“Id-sup $03 M” (FNo. 177.1331/CU)
• Group alarms (check zone):
”Id-sup CZ M” (FNo. 10410/CU),
• Single alarms (selective, module ZPS-BSZ2):
”Id-supL1-2 $03” (FNo. 177.1321/CU),
”Id-supL2-2 $03” (FNo. 177.1322/CU),
”Id-supL3-2 $03” (FNo. 177.1323/CU),
• Single alarms (selective, module ZPS-BSZ3):
”Id-supL1-3 $03” (FNo. 177.1326/CU),
”Id-supL2-3 $03” (FNo. 177.1327/CU),
”Id-supL3-3 $03” (FNo. 177.1328/CU),
• Single alarms (check zone):
”Id-sup CZ L1” (FNo. 10411/CU),
”Id-sup CZ L2” (FNo. 10412/CU),
”Id-sup CZ L3” (FNo. 10413/CU),
Linearized current
transformers
Linearized current transformers may have angle errors. The secondary current then
lags behind the primary current. In the event of a short-circuit, the CB interrupts the
primary current near current zero. The secondary current, however, continues to flow
and decays according to an e-function. The angle error and the time constant depend
mainly of the protection burden. The angle error increases and the time constant de-
creases with increasing burden.
Zero current
supervision
When the primary current is interrupted, a current continues to flow in the CT circuit
on the secondary side. The busbar protection cannot distinguish this current from a
differential current. At first, erroneous tripping is prevented by the stabilizing current.
The stabilizing current decays according to an e-function with a time constant of
64 ms. The zero current monitoring prevents spurious tripping after the stabilizing cur-
rent has decayed. If the zero crossings of the current do not recur at the latest after
32 ms (f
N
= 50 Hz) or 27 ms (f
N
= 60 Hz), the measuring system detects a DC current
and issues a selective blocking command to the protection ”Block ZeroCross”
(FNo. 10444/CU). The blocking is maintained until the current drops below the zero
current monitoring threshold again.
The zero current monitoring can be activated and deactivated with the parameter
ZERO CR SUPERV (6312A/CU).
To Next Page
Loading...
