Preparing The Connection To The Test Equipment; Connecting The Test Equipment To The Ied - ABB RET650 Series Commissioning Manual

1MRK 504 136-UUS B
6.3

Preparing the connection to the test equipment

The IED can be equipped with a test switch of type RTXP8, RTXP18 or RTXP24 or FT. The test
switch and its associated test plug handles are a part of the COMBITEST or FT system of ABB,
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 CT's, 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. When FT switch is used for testing,
care shall be exercised to open the tripping circuit, ahead of manipulating the CT fingers.
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Use COMBITEST test system to prevent unwanted tripping when the handle is withdrawn, since
latches on the handle secure it in the half withdrawn position.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 When the latches are released, the handle can be completely withdrawn from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.
6.4

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
9.
Connect the current and voltage terminals. Pay attention to the current polarity. Make sure that
the connection of input and output current terminals and the connection of the residual current
conductor is correct. 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.
Transformer protection RET650
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 grounded before testing.
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Section 6
Testing IED operation
M11743-2 v7
M11744-2 v7
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