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GE Multilin 489 Generator Management Relay 4-23
4 SETPOINTS 4.6 S5 CURRENT ELEMENTS
4
e) FLEXCURVE™
The custom FlexCurve™ has setpoints for entering times to trip at the following current levels: 1.03, 1.05, 1.1 to 6.0 in steps
of 0.1 and 6.5 to 20.0 in steps of 0.5. The relay then converts these points to a continuous curve by linear interpolation
between data points. To enter a custom FlexCurve™, read off each individual point from a time overcurrent coordination
drawing and enter it into a table as shown. Then transfer each individual point to the 489 using either the 489PC software
or the front panel keys and display.
f) DEFINITE TIME CURVE
The definite time curve shape causes a trip as soon as the pickup level is exceeded for a specified period of time. The base
definite time curve delay is 100 ms. The curve multiplier of 0.00 to 1000.00 makes this delay adjustable from instantaneous
to 100.00 seconds in steps of 1 ms.
(EQ 4.7)
where: T = Trip Time in seconds
M = Multiplier Setpoint
I = Input Current
I
pickup
= Pickup Current Setpoint
Table 4–5: FLEXCURVE™ TRIP TIMES
PICKUP
(I / I
pickup
)
TRIP TIME
(MS)
PICKUP
(I / I
pickup
)
TRIP TIME
(MS)
PICKUP
(I / I
pickup
)
TRIP TIME
(MS)
PICKUP
(I / I
pickup
)
TRIP TIME
(MS)
1.03 2.9 4.9 10.5
1.05 3.0 5.0 11.0
1.1 3.1 5.1 11.5
1.2 3.2 5.2 12.0
1.3 3.3 5.3 12.5
1.4 3.4 5.4 13.0
1.5 3.5 5.5 13.5
1.6 3.6 5.6 14.0
1.7 3.7 5.7 14.5
1.8 3.8 5.8 15.0
1.9 3.9 5.9 15.5
2.0 4.0 6.0 16.0
2.1 4.1 6.5 16.5
2.2 4.2 7.0 17.0
2.3 4.3 7.5 17.5
2.4 4.4 8.0 18.0
2.5 4.5 8.5 18.5
2.6 4.6 9.0 19.0
2.7 4.7 9.5 19.5
2.8 4.8 10.0 20.0
TM100 ms, when II
pickup
>×=