GE T60 Instruction Manual page 474

GROUPED ELEMENTS
This menu contains the settings for the transformer differential elements and the transformer thermal elements.
The thermal elements include hottest-spot temperature, aging factor and loss of life. The computation of these elements
follows IEEE standards C57.91-1995: "IEEE Guide for Loading Mineral-Oil-Immersed Transformers" and C57.96-1989: "IEEE
Guide for Loading Dry-Type Distribution Transformers". The computations are based on transformer loading conditions,
ambient temperature, and the entered transformer data.
5.7.6.2 Percent differential (ANSI 87T)
SETTINGS  GROUPED ELEMENTS  SETTING GROUP 1(6)  TRANSFORMER  PERCENT DIFFERENTIAL
 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.
5-256
 INSTANTANEOUS

 DIFFERENTIAL
 HOTTEST-SPOT

 TEMPERATURE
 AGING FACTOR


 LOSS OF LIFE


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: 90%
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
See page 5-261
See page 5-261
See page 5-262
See page 5-263
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, 1-out-of-3
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
T60 TRANSFORMER PROTECTION SYSTEM – INSTRUCTION MANUAL
CHAPTER 5: SETTINGS
in steps of 0.1
0
in steps of 0.1
0