Detection Of Quickly Evolving Problems; Figure 5.2: Ltcdiff Rate Of Rise Method - Advanced Power technologies TTC-1000 Instruction & Operation Manual

5.2 Detection of Quickly Evolving Problems

Figure 5.2 illustrates the LTCDIFF rate of rise method.
Temperature
LTCDIFF RISE
Time
LTCDIFF RATE
LTCDIFF
LTCDIFF RofR

Figure 5.2: LTCDIFF Rate of Rise Method

The LTCDIFF Rate of Rise method uses two parameters: LTCDIFF RISE and
LTCDIFF RATE. This function is disabled if either of these parameters are set to
zero. This method operates by comparing the measured rise between a start and
stop period defined by parameter LTCDIFF RATE with the programmed
parameter LTCDIFF RISE. If the measured rise is greater than or equal to the
LTCDIFF RISE for a duration equal to or greater than the LTCDIFF RATE timer,
an internal set point LTCDIFF R-R is picked up. If the LTCDIFF temperature
decreases while the LTCDIFF RATE timer is in progress, the timer will reset and
the logic will wait for another LTCDIFF temperature increase before starting the
timer again. The recommended range for setting LTCDIFF Rise is 5 to 20 C.
The LTCDIFF Rate can be set from 1 to 255 minutes.
NOTE: If the Rate of Rise set point has picked up, there is an extremely
serious problem in the tap changer and immediate attention is required.
The rate of rise feature will remain picked up unless the unit is either
powered down or it is manually reset through the front panel.
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