Sel 2414 - Thermal Alarm Limits

5.25
Date Code 20130214 Instruction Manual SEL-2414 Transformer Monitor
Metering and Monitoring
Monitoring
It is the user’s responsibility to make up an effective external contact from one or
more 52a or 52b contacts (from one or more breakers) indicating that all the
“source” breakers are open. If the user fails to assign a properly configured
digital input to TRDE, then the top-oil and hot-spot temperatures will increase
over the ambient temperature even when the power transformer is de-energized.
Thermal Alarm Limits
Top-Oil Temperature Limit (TOT1, TOT2)
Range: 50°–150°C, in 1°C steps
One of the outputs the thermal element provides is top-oil temperature. TOT1
and TOT2 determine limits for top-oil temperature. If the top-oil temperature
exceeds either limit, the corresponding TO1 or TO2 Device Word bit asserts.
Using SEL
OGIC control equations, you can configure the TOx Device Word bits
to close alarm contacts. When measured temperature inputs are available, the
relay compares the TOT1 and TOT2 settings against the measured value. Should
the measured value not be available (MTOx_OK deasserted), the relay compares
the TOT1 and TOT2 settings against the calculated top-oil value. Once asserted,
the TO1 or TO2 bits will stay asserted until the top-oil temperature drops below
98 percent of the TOT1 or TOT2 setting, respectively.
When ETHERM = 3, top-oil temperatures are measured or calculated for each of
the three single-phase transformers. The TOT1 or TOT2 Device Word bits assert
when any of the three values exceed the limits. The thermal report will show
which transformer exceeded the limits.
Figure 5.17 Top-Oil Temperature Logic
Hot-Spot Temperature Limit (HST1, HST2)
Range: 80°–300°C, in 1°C steps
One of the outputs the thermal element provides is winding hot-spot temperature.
HST1 and HST2 determine limits for hot-spot temperature alarming. If the hot-
spot temperature exceeds one of these limits, the corresponding HS1 or HS2
Device Word bit asserts. Using SEL
OGIC control equations, you can configure
T1_OILM
T1OILC
MTO1_OK
TOT1 (Setting)
TO1_1
T2_OILM
T2OILC
MTO2_OK
TO2_1
T3_OILM
T3OILC
MTO3_OK
TO3_1
TO2_2
Transformer 1
Top-Oil Logic
TOT2 (Setting)
TO1_2
TO3_2
Transformer 2
Top-Oil Logic
Transformer 3
Top-Oil Logic
TO1
TO2
TOT1 (Setting)
TOT2 (Setting)
TOT1 (Setting)
TOT2 (Setting)
TO = Top-Oil
MT = Measured Temperature
OILC = Oil Temperature, Calculated
ENABLED IF ETHERM = 3