Trip Test With The Circuit-Breaker; Figure 6.6 Checking The Earth Current Path - Siemens SIPROTEC 7SD600 System Manual

Numerical line differential protection SIPROTEC 7SD600 V3.0
The current value I1 read out is now about 2.65 times
the current value in the symmetrical test.
If the measured current practically does not change in
relation to the symmetrical test, the earth current
connection on the device has incorrect polarity.
At other values there may be swapped phases:
D Isolate and earth line.
D Correct current transformer connections.
D Repeat test.
Finally, switch off the line again. Correct the current
transformer connection again.
repeat the tests at the other end of the line.
For further checking of the current transformer and
pilot wire connections with both line ends, the main
current transformers of phase L2 are short circuited
and disconnected in both stations, in this case, the
stabilizing current I increases in the operational mea
S
sured values. The differential current I
approximately zero.

Figure 6.6 Checking the earth current path

Siemens AG January 1999
Operating instructions
6.7.4
The pilot wire protection 7SD600 allows simple te
sting of the circuit-breaker.
The block for testing this is located under the ADDI
TIONAL FUNCTIONS in the TESTS block. The TESTS
block is reached as described in section 6.7.1. The
TST I/O block is reached by changing to the next level
with ". From here the circuit-breaker test is reached
by pressing the B key twice.
When operating via a PC and the operating program
DIGSI
git address number. This is indicated in square brak
kets with the explanation text in the following exam
ples.
To test the trip circuits, the circuit-breaker may be
operated by the 7SD600 irrespective of whether an
automatic reclosure ensues or not. This test can also
be performed with an external automatic switch on.
must stay
If the circuit-breaker auxiliary contact sends the posi
D
tion of the switch to the device by a binary input, the
trip test can only be activated if the circuit-breaker is
closed. You should not ignore this added safety factor
if an external automatic switch on is available.
You go to the operating block for the actual circuit-
breaker tripping by changing to the next operating
level with ".
7SD600
L1
L2
Precondition for starting the test is that no protective
L3
function of the device is activated. A code word must
also be entered. The tripping by the circuit-breaker
test TST OFF must be programmed for the command
relay to be tested!
The device shows the respective state of the test
routine in the second display line.
System manual Order no. E50417-G1176-C069-A1

Trip test with the circuit-breaker

R
the test addresses are identified by a four-di
Danger
A successfully started test cycle can
lead to switching on of the circuit-brea
ker if an external automatic switch on is
connected!
6
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