4.9
Date Code 20090730
Instruction Manual
SEL-734 Meter
Metering
Demand Metering
Rolling demand meter response at Time = 10 minutes = 2.0/3 = 0.67 per unit.
Time = 15 Minutes
The three 5-minute intervals in the sliding time-window at Time = 15 minutes
each integrate into the 5-minute totals in
.
Rolling demand meter response at Time = 15 minutes = 3.0/3 = 1.0 per unit.
Block Demand Meter Response (EDEM=BLOK)
The block demand meter calculations are similar to rolling demand except
where the block demand meter integrates the applied signal (e.g., step current)
input over the entire DMTC setting instead of DMSI-minute subintervals.
End of Interval Pulse (EOIP)
The end of each demand interval is represented by the Meter Word bit EOIP.
The EOIP Meter Word bit is pulsed for a given time adjusted by the EOIPT
(End of Interval Pulse Timer) setting. The EOIPT setting has a range of
1–5 seconds, or OFF. If rolling demand (ROL) is enabled, the EOIP Meter
Word bit asserts at the end of every subinterval.
Predictive Demand Meter Response (EPRED=Y and EDEM=ROL or BLOK)
The SEL-734 supports the processing of predictive demand of any peak
demand value. Predictive demand is calculated and updated every second. The
predictive demand calculation is shown in
Equation 4.1
If any of the predictive demand settings are changed, predictive demand is
reset.
1.0 per unit
5 to 10 minutes
2.0 per unit total
Table 4.4
Time = 10 Minutes Intervals
(Sheet 2 of 2)
5-Minute Totals
Corresponding 5-Minute Interval
Table 4.5
Time = 15 Minutes Intervals
5-Minute Totals
Corresponding 5-Minute Interval
1.0 per unit
0 to 5 minutes
1.0 per unit
5 to 10 minutes
1.0 per unit
10 to 15 minutes
3.0 per unit total
where:
Avg = Average of 1-second averages taken already in the
demand interval
T
Elapsed
= Seconds elapsed in the current demand interval
Present = Most recent 1-second average value
T
Remaining
= Seconds remaining in demand interval
DMTC = Demand Metering time constant
PredDemand =
Avg T
Elapsed
onds
sec
(
)
Present T
Remaining
onds
sec
(
)
•
+
•
DMTC
60
•
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Содержание SEL-734
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