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SEL-300G Instruction Manual Date Code 20121214

SECTION 12: MAINTAIN AND TROUBLESHOOT RELAY

RELAY MAINTENANCE TESTING

The maintenance testing philosophy for SEL relays is very simple. Our recommendations aresummarized below:

a. Monitor the relay self-test ALARM contact to ensure that relay problems detected by

the relay itself are quickly noticed and corrected.

b. Review relay generated event reports and SER records following each operation to

ensure that relay and connection equipment performance is nominal.

c. Periodically check relay METER data for sensibility.

d. Periodically perform relay I/O operation checks.

SEL relays use extensive self-testing capabilities that detect and indicate relay problems when

they occur. By monitoring the relay ALARM contact, you are immediately notified when the

relay is out of service and can take appropriate steps to diagnose and correct the problem. Relayfunctions such as the dc monitor function and loss-of-potential function should also be used to

alarm for abnormal conditions and failures that can be detrimental to the protection system

performance if not immediately corrected.

SEL relay reporting functions such as event reports and SER records can quickly indicate

problems with the relay and other connected equipment. Using the event report current, voltage,

and relay element data, you can determine that the relay protection elements are operating

properly. Using the event report input and output data, you can determine that the relay is

asserting outputs at the correct instants and that auxiliary equipment is operating properly. We

recommend you review all relay event reports and perform detailed reviews of reports for

operations that are not nominal.

Periodically verify that the relay is making correct and accurate current and voltagemeasurements by comparing the relay METER output to other meter readings on the protected

generator. Often, simple sensibility checks are sufficient to indicate a serious problem. Relay

calibration can be verified by comparing the relay METER readings to the readings of a

calibrated meter in the same circuit. Due to the hardware design of this relay, typically, the relay

accuracy will not drift gradually, but rather will be obviously erroneous if there is a problem with

the relay data acquisition system.

To verify correct operation of relay output contacts, perform the following steps:

Isolate the relay output contacts from their dc circuits.

Using the Access Level B PULSEcommand or the front-panel CNTRL function, close the

relay output contacts individually (see Section 9: Front-Panel Operationand Section10: Serial Port Communications and Commandsfor more detailed information

regarding use of the contact control functions).

Use a continuity tester to verify that the relay contact closes when commanded.

Return the relay contacts to service in their individual circuits. Perform any additional

desired tests to verify the circuit performance.

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To verify correct operation of relay optoisolated inputs, perform the following steps:

1. Isolate the relay optoisolated inputs from their dc circuits.

Using the Access Level 1 TAR command or the front-panel TAR function, monitor the stateof the optoisolated inputs individually while you apply rated dc control voltage to the

rear-panel terminals for each input (see Section 9: Front-Panel Operationand Section

10: Serial Port Communications and Commandsfor more detailed informationregarding use of the contact control functions).

Return the relay optoisolated inputs to service in their individual circuits. Perform any

additional desired tests to verify the circuit performance.

These tests do not need to be performed more frequently than your present protection

maintenance interval. Two- to five-year intervals are acceptable, particularly if relay event

reports are reviewed as suggested above.

RELAY MISOPERATION

In the unlikely event of a relay misoperation, perform the following steps as soon as it is safe andpractical to do so:

1. Do not remove dc power from the relay. If desired, you may isolate the relay contact

outputs.

On a sheet of paper, record the state of the front-panel target LEDs. Also record the contents

of rotating display messages from the front-panel LCD display.

Press the front-panel STATUS pushbutton. If the relay STATUS is OK, continue with Step

4. If STATUS indicates a WARN or FAIL condition, use the Up and Down arrow

pushbuttons and note the failed self-test condition. Contact the factory or your local

Technical Service Center for assistance.

Using a PC, establish Access Level 1 communication with the relay. Using your terminalemulation software text capture facility, open an ASCII text file on your PC disk drive to

record relay data.

With the text file open, execute the relay HISTORYcommand. With the relay response on

the PC screen, note the relay event report numbers associated with the date and time of

the misoperation. If the operation involves optional current differential elements, record

the differential formal event report using EVE DIF n. Use the EVE ncommand to view

and store the event reports of interest. Use the SER command to view and store the relay

sequence of events record for the misoperation. Use the SHO Rcommand to record the

active SER settings. Close the text file. Section 10: Serial Port Communications and

Commandscontains information on establishing serial communications with the relay

and more details on the commands above.

You can view the stored ASCII text file containing the event information using most standard

word processing packages. It is usually helpful to select an 8 or 9 point Courier font to

view or print the event data, as this helps line up the data rows vertically on a page.

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Review the event and SER information to determine the cause of the misoperation. Section

11: Event Reports and SER Functionscontains information and examples to assist with

event and SER report review.

SEL Application Engineers are available to assist with this review, if necessary. You may be

asked to describe, fax, or e-mail the relay information you collected in the steps above as

part of this review.

RELAY TROUBLESHOOTING

Inspection Procedure

Complete the following procedure before disturbing the relay. After you finish the inspection,

proceed to the Troubleshooting Procedure.

1. Measure and record the power supply voltage at the power input terminals.

Check to see that the power is on. Do not turn the relay off.

Measure and record the voltage at all control inputs.

Measure and record the state of all output relays.

Troubleshooting Procedure

Al l Front-Panel LEDs Dark

1. Input power not present or fuse is blown.

Self-test failure.

Cannot See Characters on Relay LCD Screen1. Relay is de-energized. Check to see if the ALARM contact is closed.

LCD contrast is out of adjustment. Use the steps below to adjust the contrast.

a. Remove the relay front panel by removing the six front-panel screws.

b. Press any front-panel button. The relay should turn on the LCD back lighting.

c. Locate the contrast adjust potentiometer adjacent to the serial port connector.

d. Use a small screwdriver to adjust the potentiometer.

e. Replace the relay front panel.

Relay Does Not Respond to Commands From Device Connected to Serial Port

1. Communications device not connected to relay.

Relay or communications device at incorrect baud rate or other communication parameter

incompatibility, including cabling error.

Relay serial port has received an XOFF, halting communications. Type Qto send the

relay an XON and restart communications.

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Relay Does Not Respond to Faults

1. Relay improperly set.

Improper test source settings.

CT or PT input wiring error.

Analog input cable between transformer secondary and main board loose or defective.

Failed relay self-test.

RELAY CAL IBRATION

The SEL-300G Relay is factory-calibrated. If you suspect that the relay is out of calibration,

please contact the factory.

FACTORYASSISTANCE

We appreciate your interest in SEL products and services. If you have questions or comments,please contact us at:

Schweitzer Engineering Laboratories, Inc.

2350 NE Hopkins Court

Pullman, WA 99163-5603 USA

Telephone: +1.509.332.1890

Fax: +1.509.332.7990

Internet: www.selinc.com

Email: info@selinc.com