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1MRK511447-UEN Rev. E
8.3
Preparing the connection to the test equipment
The IED can be equipped with a test switch of type RTXP8, RTXP18 or RTXP24. The test switch and
its associated test plug handle (RTXH8, RTXH18 or RTXH24) are a part of the COMBITEST system,
which provides secure and convenient testing of the IED.
When using the COMBITEST, preparations for testing are automatically carried out in the proper
sequence, that is, for example, blocking of tripping circuits, short circuiting of CTs, opening of voltage
circuits, making IED terminals available for secondary injection. Terminals 1 and 8, 1 and 18 as well
as 1 and 12 of the test switches RTXP8, RTXP18 and RTXP24 respectively are not disconnected as
they supply DC power to the protection IED.
The RTXH test-plug handle leads may be connected to any type of test equipment or instrument.
When a number of protection IEDs of the same type are tested, the test-plug handle only needs to be
moved from the test switch of one protection IED to the test switch of the other, without altering the
previous connections.
Use COMBITEST test system to prevent unwanted tripping when the handle is withdrawn, since
latches on the handle secure it in the half withdrawn position. In this position, all voltages and
currents are restored and any re-energizing transients are given a chance to decay before the trip
circuits are restored. When the latches are released, the handle can be completely withdrawn from
the test switch, restoring the trip circuits to the protection IED.
If a test switch is not used, perform measurement according to the provided circuit diagrams.
8.4
Connecting the test equipment to the IED
Connect the test equipment according to the IED specific connection diagram and the needed input
and output signals for the function under test. An example of a connection is shown in figure 12.
Check that the input and output logical signals in the logic diagram for the function under test are
connected to the corresponding binary inputs and outputs of the IED under test.
Switchgear control unit SAM600-IO
Commissioning manual
Never disconnect the secondary connection of a current transformer circuit without first
short-circuiting the transformer's secondary winding. Operating a current transformer with
the secondary winding open will cause a massive potential build up that may damage the
transformer and cause personal injury.
To ensure correct results, make sure that the IED as well as the test equipment are
properly earthed before testing.
© 2017 - 2023 Hitachi Energy. All rights reserved
Section 8
Testing IED operation
M11743-2 v10
M11744-2 v9
39
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