Preparing The Connection To The Test Equipment; Connecting The Test Equipment To The Ied - ABB RET650 2.1 IEC Commissioning Manual

Section 9
Testing IED operation
9.3
9.4
56

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withdrawn, since latches on the handle secure it in the half withdrawn position.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released, the handle can be completely withdrawn from the test switch, restoring the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.
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.

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 10.
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
1MRK 504 160-UEN -
Transformer protection RET650 2.1 IEC
Commissioning manual