Date Code 20081022
Instruction Manual
SEL-787 Relay
Section 10
Testing and Troubleshooting
Instructi on Manual
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-787
Transformer Protection Relay. Because the SEL-787 is equipped with
extensive self-tests, traditional periodic test procedures may be eliminated or
greatly reduced.
Should a problem arise during either commissioning or periodic tests, the
section on
provides a guide to isolating and
correcting 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
command 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
and
Section 8: Front-Panel Operations
The relay generates a 15- or 64-cycle event report in response to faults or
disturbances. Each report contains current and voltage information, relay
element 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
The relay provides a Sequential Events Recorder (SER) event report that time-
tags changes in relay element and input/output contact states. The SER
provides a convenient means to verify the pickup/dropout of any element in
the relay. The
SER
command is available at the serial ports. See
Summary of Contents for SEL-787
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