4.10
SEL-734 Meter
Instruction Manual
Date Code 20090730
Metering
Demand Metering
If the calculation value is above the PREDAL (predictive demand alarm
threshold) setting, the meter asserts the PREDAL Meter Word. When the
value drops below the PREDAL level, the meter deasserts the PREDAL Meter
Word.
shows the logic used for the PREDAL alarm.
The SEL-734 requires three one-second calculations to be above the PREDAL
threshold or below the threshold in order to assert or deassert the PREDAL
Meter Word bit. This requirement minimizes the number of nuisance alarms
from starting of large loads.
Figure 4.5
PREDAL Logic
Demand Meter
Settings
Execution: every second
Set
Output
executions
Reset
PREDALD
(PREDAL Setting –1) = dropout threshold
(PREDAL Setting) = pickup threshold
PREDALP
Meter
Word
Bit
PREDAL
Group Settings
PRED
k
= value
executions
Enables
EPRED=Y
enable
calculation
EDEM=BLOK
EDEM=ROL
Group Settings
EPRED = Y
3.00
0.00
3.00
0.00
Table 4.6
Demand Meter Settings and Settings Range
Setting
Definition
Range
EDEM
Demand meter type
THM = thermal
BLOK = block
ROL = rolling
DMTC
Demand meter time constant
1, 5, 10, 15, 30, or 60 minutes
DMSI
Demand meter sub-interval
See
PDEMP
Phase demand current pickup
OFF, 0.10–3.20 Amps, secondary
NDEMP
Neutral ground
demand current pickup
OFF, 0.10–3.20 Amps, secondary
GDEMP
Residual ground
demand current pickup
OFF, 0.10–3.20 Amps, secondary
QDEMP
Negative-sequence
demand current pickup
OFF, 0.10–3.20 Amps, secondary
DBLOCK
Demand block time
OFF, 1–300 minutes
EOIPT
End of interval pulse timer
OFF, 1–5 seconds
EPRED
Predictive demand
Y, N
(hidden if EDEM
≠
ROL or BLOK)
PRED
Predicted Peak demand quantity
Any marked demand metering
quantity from
(hidden if EPRED = N or is hidden)
PREDAL
Peak demand alarm level
0–999999.99 (hidden if EPRED = N
or is hidden)
Содержание SEL-734
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