GE Multilin 850

4–120 850 FEEDER PROTECTION SYSTEM – INSTRUCTION MANUAL
PROTECTION CHAPTER 4: SETPOINTS
I
4
T CURVES
The curves for the I
4
t are derived from the formula:
Where:
T = operate time (in seconds)
TDM = Multiplier setting
I = input current
I
pickup
= Pickup Current setting
T
RESET
= reset time in seconds (assuming energy capacity is 100% and RESET is
“Timed”)
Table 4-34: I
4
T CURVE TRIP TIMES (IN SECONDS)
FLEXCURVES
The custom FlexCurves are described in detail in the FlexCurves section of this chapter.
The curve shapes for the FlexCurves are derived from the formulae:
Where:
T = operate time (in seconds),
TDM = Multiplier setting,
I = input current,
I
pickup
= Pickup Current setting,
T
RESET
= reset time in seconds (assuming energy capacity is 100% and RESET is
“Timed”)
DEFINITE TIME CURVES
The Definite Time curve shape operates as soon as the Pickup level is exceeded for a
specified period of time. The base Definite Time curve delay is in seconds. The curve
multiplier of 0.05 to 600 makes this delay adjustable from 50 to 600000 milliseconds.
Where:
T = operate time (in seconds)
MULTIPLIER
(TDM)
CURRENT (I/I
pickup
)
1.5 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0
0.01 0.1975 0.0625 0.0123 0.0039 0.0016 0.0008 0.0004 0.0002 0.00015 0.0001
0.10 1.9753 0.6250 0.1235 0.0391 0.0160 0.0077 0.0042 0.0024 0.0015 0.0010
1.00 19.753 6.250 1.235 0.391 0.160 0.077 0.042 0.024 0.015 0.010
10.00 197.531 62.500 12.346 3.906 1.600 0.772 0.416 0.244 0.152 0.100
100.00 1975.31 625.00 123.46 39.06 16.00 7.72 4.16 2.44 1.52 1.00
600.00 11851.9 3750.0 740.7 234.4 96.00 46.3 25.0 14.65 9.14 6.00