Table 5-23. Peak Demand Register Map For The Tpu2000R And Tpu2000; Figure 5-35. Demand Current Calculation; Figure 5-36. Energy Demand Calculation - ABB TPU2000 Technical Manual

100
9
0
I
TIME
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.
1000
900
KW
TIME
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.
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
40769 Peak Demand Current Phase A
40770 Peak Demand Current Phase A
40771 Peak Demand Current Phase A Year
40771 Peak Demand Current Phase A Month
40772 Peak Demand Current Phase A Day
40772 Peak Demand Current Phase A Hour
TPU2000/2000R Modbus/Modbus Plus Automation Guide
Current Demand Metering
E C
100 A = Ia ( which for this example does not change)
Reported Value Reported Value
0 90 A
INTERVAL 2
INTERVAL 1
0 5 10 15 20 25

Figure 5-35. Demand Current Calculation

Energy Demand Metering
1000 KW ( which for this example does not change)
E C
Reported Value Reported Value
0 900 KW
INTERVAL 1
INTERVAL 2
0 5 10 15 20 25

Figure 5-36. Energy Demand Calculation

Item
Reported Value
Reported Value Reported Value
99 A
98 A
INTERVAL 4
INTERVAL 3 INTERVAL 5
30 35 40 45 50 55
Time Minutes
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.
Reported Value Reported Value Reported Value
900 KW 900 KW
INTERVAL 3 INTERVAL 4
30 35 40 45 50
Time Minutes
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.
Description
Unsigned 32 Bit High Order Word MSW
Unsigned 32 Bit Low Order Word LSW
Most Significant Byte 8 Bits
00<= Range <= 99
Least Significant Byte 8 Bits
00<= Range <= 12
Most Significant Byte 8 Bits
00<= Range<= 31
Most Significant Byte 8 Bits
00<= Range <= 23
100 A
Actual Current
Read by
relay
60 70 75
900 KW
Actual
Energy
Calculated
by relay.
55 60 70 75
97