Wanted to post an example of what my home’s utility voltage looks like this time of year with hot weather and a lot of AC use. You’ll see that as soon as things begin to heat up for the day, the voltage begins to sag. Things come back up to the high end of the range in the evening. You can see instantaneous dips throughout the day as my AC starts up.
Locally, I share a 50 or 75 kVA (I forget) distribution transformer with at least 5 other houses, some of which are large 10k+ sf houses. I’m attached to a 12.8kV distribution feeder without any voltage regulators. This feeder and one other locally is supplied by a small substation 1-2 miles away (cable distance) with a single transformer fed from BGE’s 33kV subtransmission network, so there could be a tap changer there, but I don’t see any evidence of one operating on the voltage graph.
The only time I notice any voltage effects is when my AC starts up locally, and I can see a flicker in some of my lights.