GE 745 Instruction Manual page 188

S4 ELEMENTS
5.6.13.3 Aging factor limit

AGING FACTOR [
LIMIT
5–92
FIGURE 5–40: Hottest-spot limit scheme logic
PATH: SETPOINTS S4 ELEMENTS


] AGING FACTOR LIMIT
FUNCTION: Disabled
AGING FACTOR LIMIT
MESSAGE
RLYS (1-8): --------
AGING FACTOR LIMIT
MESSAGE
TARGET: Self-Reset
AGING FACTOR LIMIT
MESSAGE
PICKUP: 2.0
AGING FACTOR LIMIT
MESSAGE
DELAY: 10 min
AGING FACTOR LIMIT
MESSAGE
BLOCK: Disabled
The aging factor limit element provides a means of detecting when a transformer is aging
faster than would normally be acceptable. The element operates on the computed aging
factor, which in turn is derived from the computed hottest-spot value. The aging factor
value will revert to zero if the power supply to the relay is interrupted. The necessary
settings required for this element to perform correctly are entered under:
• AGING FACTOR LIMIT PICKUP: Enter the aging factor required for operation of the
element. This setting should be above the maximum permissible aging factor under
emergency loading condition and maximum ambient temperature.
INSULATION AGING
 
Range:
Range:
Range:
Range:
Range:
Range:
745 TRANSFORMER PROTECTION SYSTEM – INSTRUCTION MANUAL
CHAPTER 5: SETPOINTS
AGING FACTOR LIMIT
Enabled, Disabled
1 to 8
Self-Reset, Latched, None
1.1 to 10.0 in steps of 0.1
0 to 60000 min. in steps of 1
Logc Inpt 1 to 16, Virt Inpt 1 to
16, Output Rly 2 to 8, SelfTest
Rly, Vir Outpt 1 to 5, Disabled