GE T35 Instruction Manual page 247

5 SETTINGS
b) PERCENT DIFFERENTIAL

PATH: SETTINGS GROUPED ELEMENTS
 PERCENT
 DIFFERENTIAL
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The calculation of differential (I
by the following block diagram, where "" has as its output the vector sum of inputs, and "max" has as its output the input of
maximum magnitude; these calculations are performed for each phase.
The differential current is calculated as a vector sum of currents from all windings after magnitude and angle compensation.
The restraint current is calculated as a maximum of the same internally compensated currents.
The element operates if I > PKP and I
d
GE Multilin

SETTING GROUP 1(6)
PERCENT DIFFERENTIAL
FUNCTION: Disabled
PERCENT DIFFERENTIAL
PICKUP: 0.100 pu
PERCENT DIFFERENTIAL
SLOPE 1: 25%
PERCENT DIFFERENTIAL
BREAK 1: 2.000 pu
PERCENT DIFFERENTIAL
BREAK 2: 8.000 pu
PERCENT DIFFERENTIAL
SLOPE 2: 100%
INRUSH INHIBIT
FUNCTION: Adapt. 2nd
INRUSH INHIBIT
MODE: Per phase
INRUSH INHIBIT
LEVEL: 20.0% fo
OVEREXCITN INHIBIT
FUNCTION: Disabled
OVEREXCITN INHIBIT
LEVEL: 10.0% fo
PERCENT DIFF BLOCK:
Off
PERCENT DIFFERENTIAL
TARGET: Self-reset
PERCENT DIFFERENTIAL
EVENTS: Disabled
) and restraint (I ) currents for the purposes of the percent differential element is described
d r
I I I I
= + + +
d 1 2 3
comp comp comp

I K max I I I
( ,
= ,
r 1 2 3
comp comp
> I , where PKP represents a differential pickup setting and K is a restraint factor.
d r
T35 Transformer Protection System
 
TRANSFORMER PERCENT DIFFERENTIAL
Range: Disabled, Enabled
Range: 0.050 to 1.000 pu in steps of 0.001
Range: 15 to 100% in steps of 1
Range: 1.000 to 2.000 pu in steps of 0.001
Range: 2.000 to 30.000 pu in steps of 0.001
Range: 50 to 100% in steps of 1
Range: Disabled, Adapt. 2nd, Trad. 2nd
Range: Per phase, 2-out-of-3, Average
Range: 1.0 to 40.0% of f
Range: Disabled, 5th
Range: 1.0 to 40.0% of f
Range: FlexLogic™ operand
Range: Self-reset, Latched, Disabled
Range: Disabled, Enabled
I I I
+ +
4 5 6
comp comp comp
I I I
)
, , ,
4 5 6
comp comp comp comp
5.6 GROUPED ELEMENTS
in steps of 0.1
0
in steps of 0.1
0
(EQ 5.26)
(EQ 5.27)
5-113
5