GE Multilin
745 Transformer Management Relay
5-81
5 SETPOINTS
5.6 S4 ELEMENTS
5
b) HOTTEST SPOT LIMIT
PATH: SETPOINTS
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S4 ELEMENTS
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INSULATION AGING
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HOTTEST-SPOT LIMIT
The Hottest-Spot Limit element provides a means of detecting an abnormal hot spot inside the transformer. The element
operates on the computed hottest-spot value.
The Hottest-spot temperature will revert to 0°C for 1 minute if the power sup-
ply to the relay is interrupted.
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HOTTEST SPOT LIMIT PICKUP
: Enter the Hottest-spot temperature required for operation of the element. This set-
ting should be a few degrees above the maximum permissible hottest-spot temperature under emergency loading con-
dition and maximum ambient temperature.
•
HOTTEST SPOT LIMIT DELAY
: Enter a time delay above which the hottest-spot temperature must remain before the
element operates.
Figure 5–36: HOTTEST-SPOT LIMIT SCHEME LOGIC
HOTTEST-SPOT LIMIT
[ENTER] for more
HOTTEST-SPOT LIMIT
FUNCTION: Disabled
Range: Enabled, Disabled
HOTTEST-SPOT LIMIT
TARGET: Self-Reset
Range: Self-Reset, Latched, None
HOTTEST-SPOT LIMIT
PICKUP: 150°C
Range: 50 to 300°C in steps of 1
HOTTEST-SPOT LIMIT
DELAY: 10 min.
Range: 0 to 60000 min. in steps of 1
HOTTEST-SPOT LIMIT
BLOCK: Disabled
Range: Logc Inpt 1 to 16, Virt Inpt 1 to 16, Output Rly 2 to
8, SelfTest Rly, Vir Outpt 1 to 5, Disabled
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