Mounting and Commissioning
3.3 Commissioning
SIPROTEC, 7SK80, Manual
E50417-G1140-C344-A4, Release date 08.2010
324
Voltage Transformer Miniature Circuit Breaker (VT mcb)
The VT mcb of the feeder (if used) must be opened. The measured voltages in the operational measured
values appear with a value close to zero (small measured voltages are of no consequence).
Check in the spontaneous annunciations that the VT mcb trip was entered (annunciation „>FAIL:FEEDER
VT“ „ON“ in the spontaneous annunciations). Beforehand it has to be assured that the position of the VT mcb
is connected to the device via a binary input.
Close the VT mcb again: The above messages appear under the spontaneous messages as „OFF“, i.e.
„>FAIL:FEEDER VT“ „OFF“.
If one of the events does not appear, the connection and allocation of these signals must be checked.
If the „ON“-state and „OFF“–state are swapped, the contact type (H–active or L–active) must be checked and
remedied.
3.3.8 Testing the Reverse Interlocking Scheme
(only if used)
Testing reverse interlocking is available if at least one of the binary inputs available is configured for this
purpose (e.g. presetting of binary input BI1 „>BLOCK 50-2“ and „>BLOCK 50N-2“ to open circuit system).
Tests can be performed with phase currents or ground current. For ground current the corresponding ground
current settings apply.
Please note that the blocking function can either be configured for the pickup current connected (open circuit
system) or the pickup current missing (closed circuit system). For open circuit system the following tests are to
be proceeded:
The feeder protection relays of all associated feeders must be in operation. At the beginning no auxiliary
voltage is fed to the reverse interlocking system.
A test current higher than the pickup values of 50-2 PICKUP and 50-1 PICKUP or 51 PICKUP is set. As a
result of the missing blocking signal, the protection function trips after (short) time delay 50-2 DELAY.
Caution!
Test with currents above 20 A continuous current
cause an overload of the input circuits.
Perform the test only for a short time (see Technical Data, Section 4.1). Afterwards, the device has to cool off!
The direct voltage for reverse interlocking is now switched on to the line. The precedent test is repeated, the
result will be the same.
Subsequently, at each of the protection devices of the feeders, a pickup is simulated. Meanwhile, another fault
is simulated for the protection function of the infeed, as described before. Tripping is performed within time 50-
1 DELAY (longer time period) (with definite time overcurrent protection) or according to Curve (with inverse
time overcurrent protection).
These tests also check the proper functioning of the wiring for reverse interlocking.
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