GE Multilin 745

S4 Elements
745
Transformer Management Relay
Setpoints
http://www.GEindustrial.com/multilin
5–79
GE Multilin
b) Hottest Spot Limit
PATH: SETPOINTS !" S4 ELEMENTS !" INSULATION AGING ! 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 supply to
the relay is interrupted.
• HOTTEST SPOT LIMIT PICKUP: Enter the Hottest-spot temperature required
for operation of the element. This setting should be a few degrees above the
maximum permissible hottest-spot temperature under emergency loading
condition 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 5–39: Hottest-Spot Limit Scheme Logic
! HOTTEST-SPOT [!]
LIMIT
HOTTEST-SPOT LIMIT
FUNCTION: Disabled
Range: Enabled, Disabled
MESSAGE
HOTTEST-SPOT LIMIT
TARGET: Self-Reset
Range: Self-Reset, Latched, None
MESSAGE
HOTTEST-SPOT LIMIT
PICKUP: 150°C
Range: 50 to 300°C in steps of 1
MESSAGE
HOTTEST-SPOT LIMIT
DELAY: 10 min
Range: 0 to 60000 min. in steps of 1
MESSAGE
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