71M6515H Datasheet, PDF (49/57 Pages) Teridian Semiconductor Corporation – Energy Meter IC

71M6515H
Energy Meter IC
DATA SHEET
MARCH 2008
APPLICATION INFORMATION
Meter Circuits
Bits 7 through 5 (EQU) of the CONFIG register allow the selection of the metering equation that is to be implemented by the
71M6515H. The equation to be used depends on the meter configuration.
Figure 16 shows how the 71M6515H is connected for the most common configuration, the three-phase, four-wire WYE. The
neutral wire connects to V3P3A. For this configuration, equation 5 must be selected.
Distribution
transformers
A
B
C
N
CT
CT
CT
LOAD A
LOAD B
LOAD C
ANSI: Form 16S
EQU = 5
P=VA*IA+VB*IB+VC*IC
71M6515H
IA
IB
IC
V3P3A
VA
VB
VC
Figure 16: 4-Wire 3-Phase WYE Connection
In many three-phase three-wire configurations, one phase can be grounded, as shown in Figure 17. Again, the grounded wire
is connected to V3P3A. For this configuration, equation 2 must be selected.
The four-wire three-phase delta configuration is shown in Figure 20. In this case, the center tap of the transformer that
provides the A-C voltage is grounded. the grounded wire is connected to V3P3A. For this configuration, equation 2 must be
selected. For this configuration, equation 3 must be selected, i.e. P = VA*(IA-IB)/2 + VC*IC.
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