Author Topic: Mains overvoltage with domestic feed back to utility  (Read 480 times)

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Offline Sgt_BakerTopic starter

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Mains overvoltage with domestic feed back to utility
« on: April 21, 2022, 08:38:52 pm »
Hi all,

I forget whose solar roof installation was party to this particular problem, however the fundamental point was that their local mains voltage rose significantly beyond nominal - i.e. 260V for 240V nominal - during peak local solar production along the street.  Given that local fat-wires on the utility end can easily accommodate huge currents in the downstream direction, what causes the voltage rise when current should be flowing upstream?

Sorry if this is a Frequently-Asked-Question.  Have just witnessed my politicians arguing about renewable, again, and this particular aspect of modern installations doesn't make sense within own mind.

All the best,

Baker
 

Offline Someone

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Re: Mains overvoltage with domestic feed back to utility
« Reply #1 on: April 21, 2022, 10:13:39 pm »
Most home solar installs are sized far above the steady draw of the house, who actually uses 5-6kW continuously during the peak solar production hours?

One house, no so much a problem. When most houses on a low voltage feed do this at the same time its like a reverse of the "normal" (previously designed for) situation of all the houses drawing 5-6kW at the same time.

So what used to be a normal: 240V high, 220V low fluctuation from no load to 100% load, becomes 260V high (-100% load) or worse.

Double the distribution conductance and cost (halve the resistance) ? yes that would eliminate the problem, but is quite expensive. The grid wasnt engineered for this flow, but slowly slowly it can be upgraded to meet the demands, just as it was slowly updated as people built in higher and higher density. Who should pay for that upgrade is the sticky question.

 

Offline NiHaoMike

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Re: Mains overvoltage with domestic feed back to utility
« Reply #2 on: April 21, 2022, 10:43:19 pm »
Most home solar installs are sized far above the steady draw of the house, who actually uses 5-6kW continuously during the peak solar production hours?
Those who don't have net metering would have a good incentive to use it as it's being generated.
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