ADE9000 Technical Reference Manual UG-1098
Rev. 0 | Page 45 of 86
NON-BLONDEL COMPLIANT METERS
Blondel’s theorem states that there must be n − 1 measuring
elements in a meter, where n is the number of the wires of the
electric system. In this way, a Blondel compliant 4-wire wye or
4-wire delta measures three voltages and three currents. In a
3-wire delta service, at least two voltages and two currents must
be measured to be Blondel compliant.
IEC meter forms are all Blondel compliant. ANSI has some
meter forms that are not Blondel compliant, meaning that there
are fewer than n − 1 elements, so that in a 4-wire wye or 4-wire
delta, two voltage and three currents are measured. The
ADE9000 has provisions to deal with non-Blondel compliant
meter forms. Use the VCONSEL[2:0] bits in the ACCMODE
register to select what calculation to use for VB based on the VA
and VC signals.
Table 27. Non-Blondel Compliant Meter Forms
Service Type Non-Blondel Compliant ANSI Meter Form VCONSEL[2:0] VB Calculation
4-Wire Wye, 2 Voltages, 3 Currents 6S, 7S, 14S, 29S, 36S, 46S, 76S 010 VB = −VA − VC
4-Wire Delta, 2 Voltages, 3 Currents
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