GE 745 Instruction Manual page 193

CHAPTER 5: SETPOINTS
5.6.17 Tap Changer Failure
 TAP CHANGR
FAILURE
745 TRANSFORMER PROTECTION SYSTEM – INSTRUCTION MANUAL
FIGURE 5–45: Transformer overload scheme logic
PATH: SETPOINTS S4 ELEMENTS

[] TAP CHANGER FAILURE
FUNCTION: Disabled
TAP CHANGER FAILURE
MESSAGE
RLYS (1-8): --------
TAP CHANGER FAILURE
MESSAGE
TARGET: Self-Reset
TAP CHANGER FAILURE
MESSAGE
DELAY: 5.00 s
TAP CHANGER FAILURE
MESSAGE
BLOCK: Disabled
The tap changer failure element monitors the resistance seen by the tap changer
monitoring circuit. The element produces an output signal when the tap changer position
exceeds the maximum number of taps (set by the
two. This signal can be used as an alarm or as a signal to change the setpoint group. A
change in the setpoint group would be programmed through the FlexLogic™. This
approach would be useful if very sensitive settings had been used in the normal in-service
setpoint group for the harmonic restrained differential element, assuming that the tap
changer position was used to compensate the input current magnitude.
TAP CHANGR FAILURE

Range:
Range:
Range:
Range:
Range:
NUMBER OF TAP POSITIONS
S4 ELEMENTS
Enabled, Disabled
1 to 8
Self-Reset, Latched, None
0.00 to 600.00 s in steps of 0.01
Logc Inpt 1 to 16, Virt Inpt 1 to
16, Output Rly 2 to 8, SelfTest
Rly, Vir Outpt 1 to 5, Disabled
setpoint) by
5–97