We woke up to find both the UPS units with fans running and a the display indicating there are in Voltage Boost mode.

The energy monitors shows the line voltage is currently 103 volts per leg. It was a little low last night, but the log says it dropped to 102 volts about 5:00 AM.

I guess they are trying to milk everything they can out of the grid. Going down from 120 to 103 volts will reduce the power used of resistance heating appliances by about 25%.

Some appliances don't take too kindly to lower voltages like that.

All good here.

none here.....yet

None here, Reliant is saying to conserve tomorrow...

Not here - a good solid 121v - my ups has been as quiet as a mouse this whole artic even (it's quite sensitive to any issues).

Do you share a transformer with anyone? Maybe your(s) HV circuit leg has an overly heavy load - or maybe a loose connection at x-former?

Ours returned to 122 volts about 10:00 this morning.

Its not a shared residential transformer issue, The building has overloaded the single phase Oncor line in this area. The are lowering a tap-changer to reduce the current draw on the line.

Voltage squared / resistance = Watts Since this cold weather is creating a mostly resistance heating load, dropping the voltage from 240 to 210 will drop the load on the line by about 25%.

Yesterday morning, before they dropped the voltage, our power was going out every 8 minutes, then coming right back on. The line would overload and the breaker opened momentarily. The power then comes back on and all the HVAC systems start a 5 - 10 minute delayed start timer. When the heaters all get started up again, the line was overloaded again. The process repeated for three hours. This meant your house got only a minute or two of heat before the process started over again. The brownout is a better solution to problem that is ugly either way.