ABB REL 551 2.3 Series Installation And Comissioning Manual page 78




72
Preparing for test
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This section describes how to prepare the terminal in order to verify settings.
The preparation starts with making the connections to the test switch if included. This
means connecting the test equipment according to a valid terminal diagram for the spe-
cific REx 5xx terminal. The terminal can then be set in test mode in order to facilitate
the test of individual functions and prevent unwanted operation from functions other
than the tested. The test switch should then be connected to the terminal. The user could
also verify the connection and that the analog inputs signals are measured correctly by
injecting currents and voltages as required by the specific REx 5xx terminal. The tested
function should then be released. The disturbance report settings could be checked to
ensure that correct indications are given. The user could also identify the function to test
in the technical reference manual to retrieve signals and parameters names etc.
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The REx 5xx terminal can be equipped with a test switch of type RTXP 24. The test
switch and its associated test plug handle (RTXH 24) are a part of the COMBITEST
system which gives a secure and convenient testing of the terminal.
When the test-plug handle is inserted into the test switch, preparations for testing are
automatically carried out in the proper sequence (i.e. blocking of tripping circuits, short
circuiting of CT's, opening of voltage circuits, making relay terminals available for sec-
ondary injection). Terminals 1 and 12 of the test switch are not disconnected as they are
used for dc supply of the protection terminal.
The test-plug handle leads may be connected to any type of test equipment or instru-
ment. When a number of protection terminals of the same type are tested, the test-plug
handle need be moved only from the test switch of one protection terminal to the test
switch of the other, without altering previously made connections.
To prevent unwanted tripping when the handle is withdrawn, latches on the handle se-
cure it in the half withdrawn position. In this position, all voltages and currents are re-
stored to the protection terminal and any reenergizing transients are given a chance to
decay before the trip circuits are restored. When the latches are released, the handle can
be completely withdrawn form the test switch, restoring the trip circuits to the protec-
tion terminal.
If a test switch is not used necessary actions need to be taken according to circuit dia-
gram.
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