GE B90 - Page 366

5-174 B90 LOW IMPEDANCE BUS DIFFERENTIAL SYSTEM – INSTRUCTION MANUAL
GROUPED ELEMENTS CHAPTER 5: SETTINGS
5
I
2
t curves
The I
2
t curves are derived as follows:
Eq. 5-8
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 5-29: I
2
t curve trip times
Definite time curve
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 0.00 to 600.00 makes this delay adjustable from
instantaneous to 600.00 seconds in steps of 10 ms. The definite time curve shapes are defined as follows:
Eq. 5-9
Eq. 5-10
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: Timed)
5.6.6.3 Instantaneous overcurrent (ANSI 50)
SETTINGS  GROUPED ELEMENTS  SETTING GROUP 1(6)  CURRENT ELEMENTS  INSTANTANEOUS
OVERCURRENT 1(24)
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 0.44 0.25 0.11 0.06 0.04 0.03 0.02 0.02 0.01 0.01
0.10 4.44 2.50 1.11 0.63 0.40 0.28 0.20 0.16 0.12 0.10
1.00 44.44 25.00 11.11 6.25 4.00 2.78 2.04 1.56 1.23 1.00
10.00 444.44 250.00 111.11 62.50 40.00 27.78 20.41 15.63 12.35 10.00
100.00 4444.4 2500.0 1111.1 625.00 400.00 277.78 204.08 156.25 123.46 100.00
600.00 26666.7 15000.0 6666.7 3750.0 2400.0 1666.7 1224.5 937.50 740.74 600.00
 INSTANTANEOUS
 OVERCURRENT 1

IOC1 FUNCTION:
Disabled
Range: Disabled, Enabled

IOC1 CT:
F1
Range: Available current channels

IOC1 PICKUP:
1.200 pu
Range: 0.005 to 30.000 pu in steps of 0.001