5.17
Date Code 20050919
Instruction Manual
SEL-387-0, -5, -6 Relay
Metering and Monitoring
Thermal Monitor (SEL-387-6 Relay)
Load Current
The load current is reported as a per-unit value based on the transformer
rating.
In-Service Cooling Stage
The active cooling system is displayed. The displayed value is 1 for
Cooling Stage 1, 2 for Cooling Stage 2, and 3 for Cooling Stage 3. The
SEL-387-6 selects the cooling stage with the aid of contact inputs or SEL
OGIC
control equation expressions defined in settings. The settings are defined by
SEL
OGIC
control equations, using defined contact inputs or any Relay Word
elements to switch transformer constants based on the cooling stage. Only one
of the cooling stages can be active at a time.
Ambient Temperature
The value displayed (in degrees Celsius) is either the actual ambient
temperature received from the serial port or the value of the default ambient
temperature setting (DTMP), if actual temperatures are not received by the
relay.
Calculated Top-Oil Temperature
The value displayed (in degrees Celsius) is the top-oil temperature of the
transformer computed using the load current. The maximum value displayed
is 3276°C.
Measured Top-Oil Temperature
The value displayed (in degrees Celsius) is the top-oil temperature of the
transformer received from the serial port. If no data (or invalid data) are
received from the serial port, the value displayed is
-0-
.
Winding Hot-Spot Temperature
The value displayed (in degrees Celsius) is the computed value of the winding
hot-spot temperature using the actual ambient and top-oil temperatures or the
load current. The maximum value displayed is 3276°C.
Aging Acceleration Factor
The value displayed is the active insulation aging acceleration factor (FAA).
The maximum value of FAA is clamped at 9999.0.
Table 5.1
Thermal Element Conditions
Value
Description
Normal
TO1, TO2, HS1, HS2, FAA1, FAA2, CSE,
RLL, and TLL Relay Word bits are not asserted.
Warning 1
TO1, HS1, FAA1, RLL, or TLL Relay Word bit is asserted.
Warning 2
TO2, HS2, FAA2 Relay Word bit is asserted.
Warning 3
CSE Relay Word bit is asserted.
Summary of Contents for SEL-387-0
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