10.3
Date Code 20080918
Instruction Manual
SEL-749M Relay
Testing and Troubleshooting
Commissioning Tests
Step 7. Locate connector J4 and connect low-level signal connector
(e.g., ribbon cable connector of SEL-RTS Test System).
Step 8. Insert the voltage board back into Slot E.
Refer to the SEL
-
RTS Instruction Manual for additional detail.
When simulating a delta PT connection with the low-level test interface
referenced in
, apply the following signals:
Step 1. Apply low-level test signal VAB to Pin VA.
Step 2. Apply low-level test signal -VBC (equivalent to VCB) to
Pin VC.
Step 3. Do not apply any signal to pin VB.
Commissioning Tests
SEL performs a complete functional check and calibration of each SEL-749M
before it is shipped. This helps to ensure that you receive a relay that operates
correctly and accurately.
Commissioning tests should verify that the relay is properly connected to the
motor and all auxiliary equipment. Verify control signal inputs and outputs.
Use an ac connection check to verify that the relay current and voltage inputs
are of the proper magnitude and phase rotation.
Brief functional tests ensure that the relay settings are correct. It is not
necessary to test every element, timer, and function in these tests.
The following procedure is a guideline to help you enter settings into the
SEL-749M and to verify that it is properly connected. Modify the procedure
as necessary to conform to your standard practices. Use this procedure at
initial relay installation; you should not need to repeat it unless major changes
are made to the relay electrical connections.
Required Equipment
➤
The SEL-749M, installed and connected according to your
protection design.
➤
PC with serial port, terminal emulation software, and serial
communications cable.
➤
with settings appropriate to your
application and protection design.
➤
AC and dc elementary schematics and wiring diagrams for this
relay installation.
➤
Continuity tester.
➤
Protective relay ac test source—three-phase voltage and current
with phase angle control.
Connection Tests
Step 1. Remove control voltage and ac signals from the SEL-749M by
opening the appropriate breaker(s) or removing fuses.
Step 2. Isolate the relay contact assigned to be the
TRIP
output.
Step 3. Verify correct ac and dc connections by performing point-to-
point continuity checks on the associated circuits.
NOTE:
The 14-pin connectors of the
SEL-RTS ribbon cable C734
(preferred) or C750A can be used.
The connectors are not keyed; make
sure Pin 1 is connected to the IA/VA
channel on the CT and voltage board,
respectively.
Summary of Contents for SEL-749M
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