distribution transformer

Likely depends on the style of pole called for. Most I've seen do at least a 1/3 twist every five or ten towers. The difference likely isn't significant.

You'd have to ask "they that don't", as opposed to "they that do".

Most places seem to use the straight crossbar rather than the "rotated-Y" crossbar. The latter might be a bit more expensive due to the more material involved. I may be down in that part of WV this fall and will try to get over to the counties involved and see if anything like that still exists (and this time armed with a digital camera).

At low voltages such a continous transposition may be practical, but, even there, it isn't necessary to do it continuously. Easiest when it is practical to have the conductors in an equilateral triangle. At higher voltages transposition gets much more awkward and expensive as it is necessary to maintain spacing between phases at midspan, allowing for swing.

yes it is very clear and best described, actually neutral is grounded at several points of power sytem e.g. most importantly near source (generator), primary substations, secondary substations, and distribution transformer, for rapid fault detection & clearing and prevention of arcing grounds, it allows for unbalancing in distribution system etc.

ali azhar saudi arabia

D>----------------------------

yes it is very clear and best described, infact the 3phase ac neutral is grounded at several points of the power system. for example At near the source (generation), primary transformation, secondary transformation, sub secondary transformation and distribution transformation, for rapid ground- fault detection and clearing, prevention of arcing grounds, and compensation for unbalancing of load (distribution system) etc

ashiq ali eng>----------------------------