6-8 Metering and Monitoring Date Code 20010731
SEL-352-1, -2 Instruction Manual
Clearing the Breaker Monitor Report
Use the BRE C (breaker clear) command to reset the breaker operations, operations summary,
and breaker alarms after breaker maintenance.
Preloading the Breaker Monitor Report (SEL 352-2 Relay)
Use the BRE W command to preload the number of operations, total current, total energy, and
percent wear fields in the operation summary on a per-pole basis. Use this command when
installing the relay in an existing installation or when a new breaker is installed. BRE W is only
available in the SEL-352-2 Relay.
BREAKER RESISTOR THERMAL MONITOR
The SEL-352 Relay tracks the temperature of the close and open resistor for each of the three
phases. The HEAT (HEA) command displays a report of the calculated heat content of each
resistor (with respect to ambient) normalized to the resistor failure threshold, 26CF or 26TF.
For example, if the B-phase open resistor (ORB) contains 1.0 J of internal heat, and the trip
failure threshold (26TF) setting is 2.0 J, the HEA command displays the ORB resistor heat as
0.50.
The thermal report headings use a simple format. ORA heads the A-phase opening resistor
column, CRA the A-phase closing resistor column, and so on, for B-phase and C-phase.
=>HEA<ENTER>
RESISTOR HEAT IN PER UNIT TRIP VALUE
Example 500 kV Breaker Date: 6/1/96 Time: 10:16:04
ORA CRA ORB CRB ORC CRC
0.00 0.00 0.31 0.11 0.00 0.00
=>
Resetting the Thermal Monitor
The HEA C command clears the thermal models. Use the HEA C command to clear and
quickly reset the resistor heating to zero when testing the thermal elements.
STATUS MONITOR
The relay continuously runs a variety of self-tests. Some tests have warning and failure states;
others only have failure states. Identification of warnings and failures is as follows:
All warnings, represented by a W in the status report, generate an automatic serial port message
and pulse the ALARM output contact for five seconds.
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