ADE7752 Analog Devices, ADE7752 Datasheet - Page 7

• Manufacturer Part Number: ADE7752
• Description: Three Phase Energy Metering IC with Pulse Output
• Manufacturer: Analog Devices

Meter connections
In three phase service, two main power distribution services
exist: 3-phase 4-wire or 3-phase 3-wire. The additional wire
in the 3-phase 4-wire arrangement is the Neutral wire. The
voltage lines have a phase difference of ±120° (± 2π/3
radians) between each other - See Equation 5.
Where: V
different phases
The current inputs are represented by Equations 6,
Where: I
of each phase and φ
current and voltage channel of each phase.
The instantaneous powers can then be calculated as follows:
Then,
As can be seen from Equation 7, in the ADE7752 the real
power calculation per phase is made when current and voltage
inputs of the one phase are connected to the same channel (A,
B or C). Then, the summation of each individual real power
calculation gives the total Real Power information. P(t) =
P
Figure 14 demonstrates the connections of the analog inputs
of the ADE7752 with the power lines in a 3-phase 3-wire
Delta service.
REV. PrB 08/01
P
P
P
P
P
P
I
I
V
V
C
A
B
C
A
C
A
A
B
(
(
C
A
(
(
(
(t) + P
t
t
(
(
(
(
(
)
)
t
t
t
t
t
t
t
t
=
=
)
)
)
)
)
)
)
)
=
=
=
=
=
=
=
=
V
2
2
V
V
V
V
V
C
B
⋅
⋅
A
2
2
A
B
C
I
I
A
A
C
⋅
A
⋅
⋅
, I
B
(
(
(
I
⋅
⋅
, V
t
I
I
(t) + P
⋅
⋅
t
t
C
V
V
B
A
cos(
cos(
)
)
)
B
A
C
⋅
⋅
⋅
⋅
⋅
⋅
B
cos(
⋅
⋅
I
I
I
cos(
and I
cos(
B
C
ω
ω
A
cos(
cos(
and V
(
(
(
l
l
t
t
t
t
t
)
+
+
)
)
ϕ
ϕ
C
ϕ
ω
ω
C
(t)
ϕ
4
B
A
C
3
l
l
)
A
π
)
A
)
t
t
C
)
−
)
−
, φ
−
represent the RMS value of the current
+
+
V
V
represent the voltage RMS value of the
V
ϕ
4
C
B
3
B
A
C
;
π
)
⋅
⋅
⋅
;
)
and φ
I
I
I
C
B
A
⋅
⋅
⋅
PRELIMINARY TECHNICAL DATA
cos(
cos(
cos(
V
I
B
B
C
(
(
t
2
t
2
)
2
the phase difference of the
)
ω
=
ω
ω
=
l
l
l
t
t
t
2
+
+
+
2
⋅
I
8
ϕ
⋅
4
B
3
3
π
V
π
A
⋅
B
cos(
)
+
+
⋅
cos(
ϕ
ϕ
ω
C
B
l
)
t
)
ω
+
l
2
(7)
t
3
π
+
+
2
3
ϕ
π
B
)
)
(5)
(6)
– 7 –
Figure 14 - 3-phase 3-wire meter connection with ADE7752
Note: Only 2 current inputs and 2 voltage inputs of the
ADE7752 are used in this case. The Real power calculated
by the ADE7752 does not depend on the selected channel.
Figure 15 demonstrates the connections of the analog inputs
of the ADE7752 with the power lines in a 3-phase 4-wire Wye
service.
Source
Figure 15 - 3-phase 4-wire meter connection with ADE7752
Phase A
Source
Phase B
Phase A
Rf
Phase C
Ra *
Ra *
Cf
VR *
VR *
Rb *
Rb *
Ra *
Ra *
VR *
Rb *
VR *
VN
Rb *
Phase B
Cf
Cf
Cf
Cf
Phase C
Rb
CT
CT
Ra *
Rb
Rb
VR *
Rb *
CT
CT
Rb
Cf
Anti-aliasing
Anti-aliasing
Filters
Filters
Anti-aliasing
Anti-aliasing
Filters
Filters
Rf
CT
Rb
Cf
ICP
ICN
VCP
VAP
IAP
IAN
VAP
IAP
IAN
VN
IBP
IBN
VBP
Anti-aliasing
Filters
Load
IBP
IBN
VBP
Load