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ABB i-bus
EIB
2.3 Calculation of energy
10
EIB Delta-Meter
Electricity Meters
The energy consumption can be read out from the LCD display of the EIB
Delta-Meter and can also be recorded and processed remotely using the EIB
communication interface.
In the case of direct connected EIB Delta-Meters, the energy in the LCD
display is identical to the energy that has been consumed. If current and/or
voltage transformers have been used, the displayed consumption value must
be multiplied by the transformer ratio (CT x VT) in order to determine the
actual, primary energy consumption.
All transformer rated meters display secondary measured values.
The light-emitting diodes next to the meter readout and the LCD display
symbols [A] and [R], flash at a rate [Z
Direct connected meter
Transformer rated meter
The equations in the following example can be used in order to calculate the
LED/LCD flash rate at the given power.
Three-wire polyphase network with current and voltage transformers:
Type of current transformer:
Type of voltage transformer:
Secondary current (I):
Secondary voltage (U):
Power factor (cos ϕ):
Meter constant (LED, LCD) (Z
Transformer ratio of voltage transformer (VT):
Primary voltage (U
VT
=
Secondary voltage (U
Transformer ratio of current transformer (CT):
Primary current (I
CT
=
Secondary current (I
Secondary power (P
):
s
•
•
•
3
U
I
cos
P
=
s
1000
Primary power (P
):
p
•
P
=
P
p
s
LED/LCD flash frequency (B
•
P
Z
s
B
=
f
3600
LED/LCD flash period (B
B
When connected correctly, the LED and the LCD display symbol [A] should
flash approx. every 1.5 seconds in the above example.
] of:
k
1000 Imp/kWh (kvarh)
5000 Imp/kWh (kvarh)
250/5 A/A
600/100 V/V
3 A
100 V
0.9
):
5000 Imp/kWh
k
)
600
P
=
)
100
S
)
250
P
=
)
S
ϕ
•
•
3
100
V
3
A
=
1000
•
•
CT
VT
=
0.47 kWh
50
):
f
•
0.47 kW
5000
Imp/kWh
k
=
3600
):
p
1
1
=
=
=
1.53
p
0.65
Hz
B
f
V
=
6
V
A
=
50
5
A
•
0.9
=
0.47
kW
•
6
=
141
kW
=
0.65
Hz
s
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