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Inssomniak
The Glitch
Premium Member
join:2005-04-06
Cayuga, ON

Inssomniak

Premium Member

OT. - grid power weirdness..


So we got a notification Saturday afternoon that one site went offline, power went out.. UPS died. I go out to check it out and plugged in a switching ubnt power supply and it worked, same with an angle grinder I had in the truck. So I though the UPS was malfunctioning. I bypass it and the site comes up. Few seconds later the owner of the leg comes over and confirms the power is off, yet my equipment is powering. I indeed see the hydro meter is off. The site is 3 phase 600 volt with a transformer for 220/110 in the control room of the grain leg.

He figures the voltage was coming from solar panel arrays that are grid tied (they are very plentiful around here) coming down the neutral side. I was under the impression those couldn't operate without grid power. He says there wasn't a lot of power and we proved it by plugging in the angle grinder again and actually tried to cut something and it was relatively easy to stop the grinder but plenty of power to power our radios..

It was 4 pm, if his theory was correct the site would stop working at dusk...

And it did..

Hydro company fixed the power about an hour later. ..
UPS wouldn't work on the crap power..

Just another weird thing we saw in the field...

TomS_
Git-r-done
MVM
join:2002-07-19
London, UK

TomS_

MVM

I think your understanding is correct. It certainly matches mine.

Solar should stop feeding upon loss of grid power. Its the only safe way to operate. If a piece of the grid ever needs to be switched off for maintenance or an emergency, if there are solar panels feeding in you still cant work on it.

So, ironically, solar feeding sites still need an incomming power supply.

davidg
Good Bye My Friend
MVM
join:2002-06-15
00000

davidg to Inssomniak

MVM

to Inssomniak
yeah the solar sites are installed incorrectly and dangerously.

as far as the UPS goes, we had one back on a paging site in the 1990's that at about 3-4AM it would die, then come back on at 6AM sharp. the site was 5 hours away, and after a couple weeks the local store finally told me about it. So I head over after work and sit in the shelter to watch it. at midnight the UPS went to battery mode even though it had 120VAC. looking on the oscope it was a clean 60hz and I could see nothing wrong. even the protected but nonbattery outlets on the UPS still showed clean power! I changed it out to a "dumb" ups and never had a problem again. the "smart" UPS worked fine back at the office for several years too! a few years the local tech changed out the UPS when the batteries went bad and put in a new smart model. it did the exact same thing, switched to battery at midnight! Turns out there was both an AM tower that shut OFF at that time as well as a mid power TV station that went dark then. both kicked back on at 6AM, and for some reason the UPSs did not like the conditions when they were off. Exact opposite of what one would expect, but we never did figure it out.