5.18
SEL-387-0, -5, -6 Relay
Instruction Manual
Date Code 20050919
Metering and Monitoring
Thermal Monitor (SEL-387-6 Relay)
Rate of Loss of Life
The value displayed is the computed daily rate of loss of life (percent)
accumulated in a 24-hour period. This value is updated at midnight daily.
Total Loss of Life
The value displayed represents the total accumulated loss of life (percent)
since last reset.
Time to Assert TLL
The value displayed represents the estimated time (in hours) to assert the total
loss-of-life alarm (TLL Relay Word bit).
Thermal Event
Report Function
(THE n Command)
Whenever a thermal alarm condition is set (load conditions are Warning 1,
Warning 2, or Warning 3), the SEL-387-6 saves a snapshot of the thermal
status of the transformer(s) in EEPROM. The five most recent thermal events
are saved. If the command for retrieving the nth saved thermal event report is
THE
n
, where
n
is a number from one to five,
THE 1
will display the most
recent event report while
THE 5
will display the oldest thermal event report.
The format and data for the
THE
n
report are the same as for the
THE
report.
Thermal Profile
Data Report Function
(THE H and THE D
Commands)
The SEL-387-6 stores two types of trend data: one set on an hourly basis for
the last 24 hours; a second set on a daily basis for the last 31 days. The format
of the retrieved data report is suitable for display in Microsoft
®
Excel.
Hourly Profile Data Report (THE H Command)
The SEL-387-6 stores the following data on an hourly basis for the last 24
hours. The data are stored at the beginning of each hour.
➤
One-hour average ambient temperature
➤
One-hour average calculated top-oil temperature
➤
One-hour average measured top-oil temperature
➤
One-hour average winding hot-spot temperature
➤
One-hour average per-unit load current
➤
One-hour average insulation aging acceleration factor (FAA)
The format for the
THE H
report is as follows:
NOTE:
When the thermal model is
applied on one three-phase
transformer (XTYPE = 3), the
SEL-387-6 displays only the values for
Transformer 1; when the thermal
model is applied on a set of three
single-phase transformers
(XTYPE = 1), the SEL-387-6 displays
the values for Transformer 1,
Transformer 2, and Transformer 3.
Summary of Contents for SEL-387-0
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