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I live in a small town that is 2400/4160v primary and have not seen the voltage issues that others are experiencing, I show 118V despite being on the same 69kv/4160v substation transformer as the nearby large plastics plant. Neighborhoods are dotted with the old black oval & round side bushing transformers fed with either hard drawn or stranded copper with many of the houses using exposed hard copper drops. I'm a lead at the plastics plant and run the 1000-ton presses, Springfield-1000 takes 1200A/phase at 480V with the extruder heaters taking over half that. The plant 4160 primary is fed by several runs of 5KMCM and secondary is 4 bus runs at 2500A/480Y for the large products area. The electric bill is over $100K/week.
I did measure my outlet voltage over the thanksgiving weekend as the plant was "cold" and it was running 118.9V on my Fluke 8010A
As antiquated as my local local power system is I have to wonder why others are having so many issues with high line voltages, 130V would be the upper limit. The internal power transformer of say a CTC-25 could withstand 150V on the primary but the horizontal output might not as this could introduce a runaway condition possibly arcing over the flyback or pushing the 6JE6 beyond its safe dissipation.
I have a T940 Magnavox with the NORM/HIGH line switch, clearly this was a concern back in the late 60's. Running I find +420V going into the filter choke and about 5.9-6.2V on the heater fuse to ground, normal but a rise to 130+ primary would push this to almost 7V and over 460V on the B+. Clearly makes a good argument for a 500VA Sola transformer as I doubt the utility is going to address anything below 140V calling it an isolated incident.
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