ABB RELION REX640, Техническое руководство, Страница: 667 / 1960

• Earthing check of the individual CT secondary circuits to verify that each three-
phase set of main CTs is properly connected to the station earth and only at one
electrical point.
• Insulation resistance check.
• Phase identification of CT shall be made.
CT and VT connectors are pre-coded, and the CT and VT connector
markings are different. For more information, see the installation manual.
De-energize the CT primary side and disconnect the CT secondary
circuits from the protection relay while carrying out the CT core
excitation curve plotting.
If the CT secondary circuit is opened or its earth connection is missing
or removed without the CT primary being de-energized first, dangerous
voltages may be produced. This can be lethal and cause damage to the
insulation. The re-energizing of the CT primary should be prohibited as
long as the CT secondary is open or unearthed.
Checking of the power supply
Check that the auxiliary supply voltage remains within the permissible input voltage
range under all operating conditions. Check that the polarity is correct before
powering the protection relay.
Checking binary I/O circuits
Always check the binary input circuits from the equipment to the protection relay
interface to make sure that all signals are connected correctly. If there is no need
to test a particular input, the corresponding wiring can be disconnected from the
terminal of the protection relay during testing. Check all the connected signals so
that both input voltage level and polarity are in accordance with the protection relay
specifications. However, attention must be paid to the electrical safety instructions.
Always check the binary output circuits from the protection relay to the equipment
interface to make sure that all signals are connected correctly. If a particular
output needs to be tested, the corresponding wiring can be disconnected from
the terminal of the protection relay during testing. Check all the connected
signals so that both load and polarity are in accordance with the protection relay
specifications. However, attention must be paid to the electrical safety instructions.
Checking of optical connections
Check that the Tx and Rx optical connections are correct.
A relay equipped with optical connections requires a minimum depth of
180 mm (7.0866 in) for plastic fiber cables and 275 mm (10.8268 in) for
glass fiber cables. Check the allowed minimum bending radius from the
optical cable manufacturer.
Applying of required settings for the protection relay
Download all calculated settings and measurement transformer parameters in the
protection relay.
1MRS759142 F Protection functions
REX640
Technical Manual
667