On Sun, 22 Nov 2009 09:00:36 +0000, Adrian Brentnall wrote:

Well - I know that last night was a bit wild out here (understatement!)
but the mains tripped out three or four times between 7:30 and 9:30 -
varying lengths of time - longest being about 10 mins

I was going to ask if it was related to the weather. Seems as if it
is due to movement of the wires and/or stuff close to the lines. It
might be a failling insulator but once they have a track over them
they tend to stay "failed".

Yes - it would be advantageous. Is that what the serial / usb connection
is all about - the box tells the PC to shut down in a tidy fashion ?

Yes, you have a bit of software on the connected PC that monitors the
UPS and shuts the PC down when given criteria are met. Other PC's
also supported by that UPS should also shutdown but not sure how you
do that in a windoze enviroment.

Speaking to the engineer the other day - he reckoned that there was
'something' that was tripping the circuit - and the data recording stuff
was registering a fault current of 80A (at 11kv!) just before the thing
tripped out.

Only about the same as the load presented by 800 odd homes but makes
a bit of a bang when disipated all on one place. Presumably by "fault
current" he meant 80A going to ground rather than 80A of load.

He commented that bits of tree don;t last all that long in that
situation - but didn't say that he'd found the fault....

They normally don't at least not fresh growth or small twigs say up
to an inch in dia it just explodes. Bigger drier bits may last a lot
longer.

We're on the end of a wire - two of us sharing a poletop transformer -
and I suspect that the mains isn't all that clean, as various bits of
electrickery have failed in the last 3 years...

We have around 1/2 km of single phase 11kv spur to "our" pole
transformer. The three phase 11kv to the spur is about 4km long. Get
a decent UPS and you'll be able to log the supply voltage. That may
well be quite enlightening.

Ah well - we do have a great view ! g

So do we.


--
Cheers
Dave.