Date Code 20170927 Instruction Manual SEL-751 Relay
Section 11
Testing and Troubleshooting
Overview
Relay testing is typically divided into two categories:
➤ Tests performed at the time the relay is installed or
commissioned
➤ Tests performed periodically once the relay is in service
This section provides information on both types of testing for the SEL-751
Feeder Protection Relay. Because the SEL-751 is equipped with extensive
self-tests, traditional periodic test procedures can be eliminated or greatly
reduced.
Should a problem arise during either commissioning or periodic tests, the sec-
tion on Troubleshooting on page 11.16 provides a guide to isolating and cor-
recting the problem.
Testing Tools
Serial Port
Commands
The following serial port commands assist you during relay testing.
The METER command shows the ac currents and voltages (magnitude and
phase angle) presented to the relay in primary values. In addition, the com-
mand shows power system frequency. Compare these quantities against other
devices of known accuracy. The METER command is available at the serial
ports and front-panel display. See Section 7: Communications and Section 8:
Front-Panel Operations.
The relay generates a 15, 64, or 180-cycle event report in response to faults or
disturbances. Each report contains current and voltage information, relay ele-
ment states, and input/output contact information. If you question the relay
response or your test method, use the event report for more information. The
EVENT command is available at the serial ports. See Section 10: Analyzing Events.
The relay provides a Sequential Events Recorder (SER) event report that time-
tags changes in relay element and input/output contact states. The SER pro-
vides a convenient means to verify the pickup/dropout of any element in the relay.
The SER command is available at the serial ports. See Section 10: Analyzing Events.
Use the TARGET command to view the state of relay control inputs, relay
outputs, and relay elements individually during a test. The TAR GET com-
mand is available at the serial ports and the front panel. See Section 7: Com-
munications and Section 8: Front-Panel Operations.
To Next Page
Loading...
