GE 845 Instruction Manual page 248

PROTECTION
4–144
Figure 4-58: Differential/Restraint Characteristic
d
Pickup
The above figure shows the differential/restraint characteristic of the main transformer
percent differential protection
Path:
Setpoints > Protection > Group 1 (6) > Transformer > Percent Differential
..\Transformer\Percent Differential 1
Item Name
Function
Pickup
Slope 1
Break 1
Break 2
Slope 2
Pickup Delay
Inrush Inhibit Function
Inrush Inhibit Level
Inrush Inhibit Mode
Overexcitation Inhibit
Overexcitation Level
Block
Percent Output Relays
Instantaneous Diff Function
Inst Diff Pickup
Inst Diff Block
Inst Diff Output Relays
Events
Targets
PcntDiff1
FUNCTION
Range: Disabled, Trip, Configurable
Default: Disabled
The selection of the Trip, or Configurable setting enables the Percent Phase Differential
function. The trip output relays selected to trip each breaker will operate, if the Percent
Differential protection operates and these trip outputs are selected in the Percent
Differential menu as "Operate".
Operate
Slope 2
Slope 1
Value
Disabled
0.20
25
1.50
4.00
95
0.000
Disabled
20.0
Per Phase
Disabled
10.0
Do Not Operate
Disabled
10.00
Off
Do Not Operate
Enabled
Latched
845 TRANSFORMER PROTECTION SYSTEM – INSTRUCTION MANUAL
CHAPTER 4: SETPOINTS
Block
restraining
r
Unit
x CT
%
x CT
x CT
%
s
%
%
x CT