Sel 787 - Advanced Relay Settings; Setting Compensation and Logic Parameters; Global, Front-Panel, and Report Settings; Communications Ports and Protocol Setup

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f. Set the current compensation setting ICOM. When set to Y, this setting enables the individual CT
compensation settings W1CTC and W2CTC.
g. Set the neutral CT ratio CTRN1.
h. Enable and set the differential element settings. Set the differential element pickup, slope, and harmonic
blocking and/or restraint characteristics for the transformer application.
i. Enable and set the optional restricted earth fault (REF) protection elements if the application calls for it.
j. Enable backup overcurrent elements. Select instantaneous and time-overcurrent elements as necessary to
provide backup protection and coordination.
k. Enable and enter RTD settings if RTDs are used for temperature measurements in the transformer tank and
ambient air temperature.
l. If voltage measurements are supported in the relay:
➢ Enable and set over- and undervoltage protection elements.
➢ Enable and set volts/Hz protection elements (overexcitation protection).
➢ Enable and set power elements as the application requires.
➢ Enable and set over- and underfrequency elements necessary for the application.
➢ Enable and set demand and peak demand metering as necessary.
➢ Set the trip/close logic settings using the Relay Word bits of the enabled protection and logic elements
to drive the transformer trip logic and the winding breakers trip logic.
Group 1 Logic Settings
a. Enable and enter SEL
OGIC equations settings according to the needs of the application.
b. Repeat previous steps for Group 2, 3, and 4 settings if necessary for the application.
Global Settings
Review, enable, and enter the Global settings the application requires. Global settings include synchrophasors,
through-fault event monitoring, breaker failure, etc.
Front-Panel Settings
a. Configure relay display points. Use the front-panel display to indicate fault conditions, alarms, and operational
parameters.
b. Configure relay front-panel target indications.
Report Settings
a. Configure relay event reporting (ER) to capture relay trip conditions.
b. Configure and set the SER (sequence-of-events report) settings.
c. Configure and set the LDP (load profile report settings) report, if necessary.
Communications Ports and Protocol Settings
Enable and enter the communications ports and protocol settings as necessary for the application.
Step 4. Save the revised setting file into the database, and then with the settings still open, click the Send Active Settings
icon and then click OK when prompted to upload the revised settings into relay.
Step 5. Perform relay verification and commissioning tests per your requirements. Refer to Section 10 in the SEL-787
manual for details on relay testing.
NOTE: Be sure to evaluate and confirm all relay settings before implementing this application on an actual transformer.
*PLS787-02*
© 2008–2013 Schweitzer Engineering Laboratories, Inc. All rights reserved. Date Code 20130426
Relay Settings