GE T60 Instruction Manual page 360

5.6 GROUPED ELEMENTS
b) PERCENT DIFFERENTIAL

PATH: SETTINGS GROUPED ELEMENTS
 PERCENT
 DIFFERENTIAL
5
The calculation of differential (I
by the following block diagram, where "Σ" 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
restraint factor defined by the relays settings Slope 1, Slope 2, and a transition area between breakpoint 1 and breakpoint 2
settings.
5-214

SETTING GROUP 1(6)
PERCENT DIFFERENTIAL
FUNCTION: Disabled
PERCENT DIFFERENTIAL
MESSAGE
PICKUP:
PERCENT DIFFERENTIAL
MESSAGE
SLOPE 1:
PERCENT DIFFERENTIAL
MESSAGE
BREAK 1: 2.000 pu
PERCENT DIFFERENTIAL
MESSAGE
BREAK 2: 8.000 pu
PERCENT DIFFERENTIAL
MESSAGE
SLOPE 2: 100%
INRUSH INHIBIT
MESSAGE
FUNCTION: Adapt. 2nd
INRUSH INHIBIT
MESSAGE
MODE: Per phase
INRUSH INHIBIT
MESSAGE
LEVEL: 20.0% fo
OVEREXCITN INHIBIT
MESSAGE
FUNCTION: Disabled
OVEREXCITN INHIBIT
MESSAGE
LEVEL: 10.0% fo
PERCENT DIFF BLOCK:
MESSAGE
Off
PERCENT DIFFERENTIAL
MESSAGE
TARGET: Self-reset
PERCENT DIFFERENTIAL
MESSAGE
EVENTS: Disabled
) and restraint (I ) currents for the purposes of the percent differential element is described
d r
I I I
= +
d 1 2
comp comp
I max I
( ,
=
r 1
comp
> PKP and I / I > K, where PKP represents a percent differential pickup setting and K is a
d d r
T60 Transformer Protection System

TRANSFORMER
Range: Disabled, Enabled
Range: 0.050 to 1.000 pu in steps of 0.001
0.100 pu
Range: 15 to 100% in steps of 1
25%
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
+ + +
3 4 5
comp comp comp
I I I I
)
, , ,
2 3 4 5
comp comp comp comp
5 SETTINGS

PERCENT DIFFERENTIAL
in steps of 0.1
0
in steps of 0.1
0
(EQ 5.27)
(EQ 5.28)
GE Multilin