Harris Institute of Technical Training

We have 12Kv 3 wire distribution sys. Engineering wants better PQ on each phase. So here is the question. What is the problem with metering the 3 wire system with 9S meter using 3 CTs & 3 VTs with VT secondaries starred much like a 4 wire system. VTs wired Delta on the primary and Wye on the secondary. Is there a phase shift? If so can it be corrected with reactiformer? Has this ever been done?

If you measure and combine the instantaneous power phasors on the three wires of the three wire system, the result will be zero. Blondel's theorem talks abour n-1 metering elements on a system of n conductors. Another way of phrasing this is, the phasoral sum of the instantaneous powers on n-1 conductors in a system of n conductors is equal to and opposite the power phasor on the remaning conductor.