130804-0822 EDT
Cleveland Apprentice:
First, definitions. In an electrical distribution circuit "upstream" means toward the power source, and "downstream" means away from the power source.
My location is possibly 10 customers downstream from the substation, and there are possibly 20 customers further downstream after me. Somewhere at or between the substation and my location there are parallel circuits. The single downed wire was about 250 ft downstream from my transformer. The distribution to me is like an ungrounded delta, except at the substation this is supplied by a wye transformer. Thus, each of the primary phase wires has the same voltage magnitude to earth, and can not be moved much from that relationship.
The two primary wires to my transformer I shall call A and B. The various customers on this this three phase system will be somewhat uniformly distributed between the three phases. Thus, some are A to B like me, and others are B to C and A to C. This is important to the analysis.
The arcing short to earth was a high impedance compared to the source impedance of the substation transformer, and the wire from the substation to the point of arcing. This is identified by my oberservation that when arcing was present that my voltage did not drop much.
Assume the arcing is from the phase A wire. Downstream from my location there is no customer connection to my wire A because the wire is broken. Upstream there are some customers connected between A and B or C.
When DTE opened wire A upstream from my location, at the substation or some intermediate point (most likely), then I had large voltage flucuations. Some of the 10 or more upstream neighbors, and I are connected to primary wire A with no connection to anything except some of my neighbors and me. What is the cause of the voltage I saw and the large swings in value?
.