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[aprssig] 3' snow emergency (generators)

Robert Bruninga bruninga at usna.edu
Tue Feb 9 17:18:38 UTC 2010


>> Lets see, a house without power is say 
>> about 1 ohm or less (since every thermostat
>>  in the house eventually closes).  Parallel 
>> that with about 100 more houses... and we 
>> are talking about maybe 0.01 ohm.
> 
> What has thermostats got to do with it? 
> Thermostats for house heating are not 
> connected across 110 vac but use low 
> voltage instead. 

The number 1 problem in any power outage is that eventually
everyone's hot water cools, their house cools, (or in the summer
warms) and every single one of those thermostats mechanically
closes.  The result is that bringing the grid back up in any
area has to contend with the worst-possible load all at once.
That is why they ask everyone to turn off everything to help
with this re-powering PEAK load.  And why they have to bring up
small areas one at a time.

That is also why they also pay-you $10 per month if you let them
put a smart disconnect on your hot water heater and heat-pump so
that they can send a radio signal to cause your 8 KW hot water
heater and 10 KW heatpump to NOT come back on instantly, but
wait until they have the load balanced under their control.

That was my reference to thermostats.
Bob, Wb4APR




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