GE Feeder Management Relay 750 Instruction Manual page 149

5 SETPOINTS
d) ANALOG INPUT RATE OF CHANGE
PATH: SETPOINTS S6 MONITORING
A/I RATE 1
[ENTER] for more
The relay has fast and slow analog input rates of change. The fast rate of change measures over the last one minute inter-
val and detects a rapid increase or decrease in the input quantity. The slow rate of change measures over the last one hour
interval and detects the long term trend of the input quantity. A positive rate indicates an increasing analog input and a neg-
ative rate indicates a decreasing analog input.
The fast (slow) analog input rate of change is calculated as follows. Every second (minute) the present analog input reading
is captured and a new rate of change calculated for the previous minute (hour). The rate is calculated using the previous
sixty analog input readings and the 'Least Squares Approximation' method that generates an equation for the best line
through the sample points as shown below. The rate of change is equal to the slope of this line which is a stable quantity
not unduly affected by noise or fluctuations from the input.
GE Multilin
Courtesy of NationalSwitchgear.com
Figure 5–45: ANALOG INPUT THRESHOLD LOGIC
A/I A/I RATE 1(2)
ð
A/I RATE 1
ENTER
ESCAPE
FUNCTION: Disabled
A/I RATE 1
ESCAPE
MESSAGE RELAYS (3-7): -----
A/I RATE 1 PICKUP:
ESCAPE
μ
MESSAGE 10.0 A /hour
A/I RATE 1
ESCAPE
MESSAGE DELAY: 0 s
750/760 Feeder Management Relay
5.7 S6 MONITORING
Range: Disabled, Alarm, Latched Alarm, Control
Range: Any combination of the 3 to 7 Auxiliary Relays.
See 5.6.1: Overview on page 5–32 for details.
Range: 0 to 65535 units in steps of 1. Units reflect the
UNITS setpoint value.
Range: 0 to 60000 s in steps of 1
5
A/I
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