3.3 Commissioning
421
7SA522 Manual
C53000-G1176-C155-3
At least one stage of the earth fault protection must be set to be directional (address
31xx of the earth fault protection). The test current on the line must exceed the pickup
threshold setting of these stages; if necessary the pick-up threshold must be reduced.
The parameters that have been changed, must be noted.
Figure 3-27 Polarity check of I
4
, example with earth current from a power transformer star-point
After switching the test source on and off again, the direction indication must be
checked: In the fault log the messages ´()3LFNXSµ and ´()IRUZDUGµ must at
least be present. If the directional pick-up alarm is missing, a connection error of the
earth current connection I
4
is present. If the wrong direction is indicated, the earth
current connection I
4
has a swapped polarity. In the previous case the connection must
be rectified after the test source has been switched off. The measurements must then
be repeated.
If the pick-up alarm is missing altogether, this may be due to the fact that the test
current is too small.
Note
If parameters were changed for this test, they must be returned to their original state
after completion of the test !
3.3.11 Measuring the Operating Time of the Circuit Breaker
Only for Synchro-
nism Check
If the device is equipped with the function for synchronism and voltage check and it is
applied, it is necessary - under asynchronous system conditions - that the operating
time of the circuit breaker is measured and set correctly when closing. If the synchro-
nism check function is not used or only for closing under synchronous system condi-
tions, this subsection is irrelevant.
For measuring the operating time a setup as shown in Figure 3-28 is recommended.
The timer is set to a range of 1 s and a graduation of 1 ms.
To Next Page
Loading...
Need help?
General
