ABB TPU2000, Technical Manual

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TPU2000/2000R Modbus/Modbus Plus Automation Guide
97
Current Demand Metering
100 A = Ia ( which for this example does not change)
Time Minutes
I
0 5 10 15 20 25 30 35 40 45 50 55 60 70 75
9
0
At Time = 15 min.
Current is integrated logarithmically for the entire window
time selected ( in this case 15 min) such that the reported
value is 90 % of the present value at the end of demand time.
The Demand value register is updated every demand cycle
which in this case is every 15 minutes.
100
INTERVAL 1
TIME
Actual Current
Read by
relay
INTERVAL 2
INTERVAL 3
Interval sample is taken every 32 cycles (533 mS at
60 Hz). The logaritmic function shall report 90% of
the integrated value calculated beneath the demand
curve.
Reported Value
0 Reported Value
90 A Reported Value
98 A
INTERVAL 4
INTERVAL 5
Reported Value
99 A
Reported Value
100 A
EC
Figure 5-35. Demand Current Calculation
Energy Demand Metering
1000 KW ( which for this example does not change)
Time Minutes
KW
0 5 10 15 20 25 30 35 40 45 50 55 60 70 75
At Time window end= 15 min,(selected demand interval),
30 minutes,45 minutes,...the relay updates the demand register
with the calculated energy value.
If the relay is reset prior to the demand window time elapsing,
the time shall reset to 0.
1000
TIME
Actual
Energy
Calculated
by relay.
INTERVAL 1
Interval sample is taken every 1/15 th of
the selected demand interval (in this case every minute).
The logaritmic function shall report 90% of
the integrated value calculated beneath the demand
curve.
Reported Value
0 Reported Value
900 KW Reported Value
900 KW Reported Value
900 KW Reported Value
900 KW
900
INTERVAL 2 INTERVAL 3 INTERVAL 4
EC
Figure 5-36. Energy Demand Calculation
Figures 5-35 and 5-36 illustrate the energy and current calculation methods and data reported when accessed via
the network. To simplify the explanation, the current and energy has been kept constant. This example illustrates
a calculation based upon a window size of 15 minute demand intervals.
Table 5-23. Peak Demand Register Map for the TPU2000R and TPU2000
Register
Address Item Description
40769 Peak Demand Current Phase A Unsigned 32 Bit High Order Word MSW
40770 Peak Demand Current Phase A Unsigned 32 Bit Low Order Word LSW
40771 Peak Demand Current Phase A Year Most Significant Byte 8 Bits
00<= Range <= 99
40771 Peak Demand Current Phase A Month Least Significant Byte 8 Bits
00<= Range <= 12
40772 Peak Demand Current Phase A Day Most Significant Byte 8 Bits
00<= Range<= 31
40772 Peak Demand Current Phase A Hour Most Significant Byte 8 Bits
00<= Range <= 23