5.13
Date Code 20130214 Instruction Manual SEL-2414 Transformer Monitor
Metering and Monitoring
Monitoring
When the SEL-2414 is connected in this mode, no power calculations can be
made because each CT is monitoring current on a different winding. See
Table I.1 for a list of which metering quantities are set to 0 when ETHERM = W.
Operating Characteristic
Figure 5.13 shows a block diagram of how the temperature, current, and cooling
system inputs are used to create transformer monitoring information and alarms.
Top-oil temperature is a calculation of the transformer oil temperature at the top
of the tank, while hot-spot temperature is a calculation of the hottest point on the
transformer winding. The thermal element uses hot-spot temperature to calculate
the insulation aging acceleration factor, FAA, daily rate of loss of life, RLOL,
and total loss of life, TLOL. For each of these quantities you can set a threshold
beyond which a Device Word bit will assert (Figure 5.17 and Figure 5.18). The
SEL-2414 thermal element compares top-oil and winding hot-spot temperatures
against thresholds beyond which Device Word bits (TO1, TO2 and HS1, HS2,
respectively) will assert. You can use these bits to alarm for overheating of the
transformer (Figure 5.17 and Figure 5.18).
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