I work as a lineman and had this experience. A contractor that does rural work stated that we still had old wye voltage in town. I was confussed, so I asked him to explain. He went on to tell me he was used to 4 wire delta, and thought wye was outdated. Within the city limits we have some 4 wire delta secondary, but have 10 fold more wye. Does anyone have an idea of the %"s of wye -vs- delta secondary in the US.
Wye -vs- Delta
- Thread starter lineman18
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- San Francisco Bay Area, CA, USA
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- Electrical Engineer
4 wire delta systems were designed for small 3 phase / 1 phase mixed use installations, typically limited to 75kVA or less. So if he lived somewhere were they had a lot of small manufacturing or light commercial users, it's entirely possible that this was his experience. But it would be the exception rather than the norm. I doubt the percentages or 4WD vs 4WY are even 2 digits over the entire US, but you might find pockets where it remains as a legacy with higher percentages. Almost all new installations are going to be Wye now though, it's better for maintaining balance on the utility grid.
I would agree with all coments. One more factor is that as a lineman I'm asked to build a delta rather than wye if we have only two primary phases and a neutral. This way the company can save money by building an open delta whith only two transformers, cutouts, arrestors, and save miles of wire. This is used mostly outside the city limits where 3 phase is not in place.
Graphs of the Y-Δ transform. Each graph connects the nodes N1, N2, N3; the transform is a simple calculation of the flows through the edges of one graph given the flows through the edges of the other graph. The primary application of the transform is in design and analysis of electrical circuits, but it is a theorem of graph theory, meaning that it can also be applied in other fields.
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