What to do in a power cut

EricMears

I had a visit from a local electricity board rep yesterday telling me that on a day (yet to be fixed) in a few weeks time they'll be switching off our adjacent 11kV line to allow trimming the trees alongside it.

Unlike former years where they just switched it off for 8 hrs they're proposing to bring in mobile generators to maintain a supply. Our house is served by a transformer that doesn't do any other houses.

I'm really not sure what's going to happen on the SP front !

My best guess is that the generator will allow the panels to generate but as there's no connection anywhere else it will only generate as much as I can manage to use. But I can't completely discount the possibility that us feeding the generator would trip it out. Unlikely (but not impossible) that some damage might be caused to inverter.

Has anyone else been in this situation or have a good idea what will happen ?

Fruit_and_Nut_Case

You still have an "Electricity Board"? How last-century is that.

Seriously, I guess your visitor might have known the answer to your query. Did (s)he not notice the shiny panels on your roof?

EricMears

Fruit_and_Nut_Case wrote: »

You still have an "Electricity Board"? How last-century is that.

Seriously, I guess your visitor might have known the answer to your query. Did (s)he not notice the shiny panels on your roof?

I'm a last century person ! I think he was probably from WPD - but they may well have changed their name again recently (they seem to most months ).

I did point the panels out but he wasn't sure how they'd affect his generator or vice versa.

I've also asked same question of my SP installer - who has several other customers (inc his own dad) who will be affected similarly that day, although most of them have a few neighbours who will be able to take any exports.

EricMears

Just had following response from installer :-


"I’ve just spoken to SMA regarding the power cut, they say it’sbest to shut down the solar to avoid the possibility of any damage. But theyalso said that the DNO will run the generator at around 51 hertz which isoutside the parameters of the inverter and will automatically shut it down anyway. "

Not sure which day it will be yet but Sod's Law predicts it will be the sunniest day this year (just like it was last year when a fault condition shut us down for 8h )

legoman62

EricMears wrote: »

I had a visit from a local electricity board rep yesterday telling me that on a day (yet to be fixed) in a few weeks time they'll be switching off our adjacent 11kV line to allow trimming the trees alongside it.

Any chance of visiting shafeeq's while he's at it:rotfl:

rogerblack

EricMears wrote: »

I had a visit from a local electricity board rep yesterday telling me that on a day (yet to be fixed) in a few weeks time they'll be switching off our adjacent 11kV line to allow trimming the trees alongside it.

Unlike former years where they just switched it off for 8 hrs they're proposing to bring in mobile generators to maintain a supply. Our house is served by a transformer that doesn't do any other houses.

As a general point - do not assume that the generator will actually materialise/be used.
I had some repairs done on my local network, which were scheduled for 9-10 and 5-6 - with a generator in between.
Was off 9-5.
Take usual precautions - put freezer on 'boost' mode the day before, or set the thermostat all the way down if it doesn't have one - if it's mostly empty, add a few bottles of water to freeze.

EricMears

rogerblack wrote: »

As a general point - do not assume that the generator will actually materialise/be used.

Apart from the (now vanished) hope that it might keep the inverter running, I'm not too bothered about the generator. I have one of my own as well as a UPS that ought to cope with base load.

zeupater

EricMears wrote: »

Apart from the (now vanished) hope that it might keep the inverter running, I'm not too bothered about the generator. I have one of my own as well as a UPS that ought to cope with base load.

Hi Eric

Anything other than a very large UPS will probably be no good for the main baseload units such as fridges & freezers unless the compressors are soft-start ... I take it that you can 'island' the house supply and have a suitable connector ready for the generator, or will you simply be plugging the necessary baseload items into the generator feed ??

Z

rogerblack

zeupater wrote: »

Hi Eric

Anything other than a very large UPS will probably be no good for the main baseload units such as fridges & freezers unless the compressors are soft-start ... I take it that you can 'island' the house supply and have a suitable connector ready for the generator, or will you simply be plugging the necessary baseload items into the generator feed ??

As a random point - my APC 750 sine-wave UPS will run my fridge and freezer happily.
(Probably not if they happened to turn on at the same moment)

EricMears

zeupater wrote: »

I take it that you can 'island' the house supply and have a suitable connector ready for the generator, or will you simply be plugging the necessary baseload items into the generator feed ??

Z

Still expecting that WPD will turn up with generator as promised.

If not then UPS already runs this computer & our Sky+ box (also some lights and the central heating system but I'm not expecting to need them). If I have to use our generator then it will probably only be to give the fridges a boost for an hour or so around noon or to start up any appliance we decide we urgently need.

zeupater

rogerblack wrote: »

As a random point - my APC 750 sine-wave UPS will run my fridge and freezer happily.
(Probably not if they happened to turn on at the same moment)

Hi

If it doesn't trip out when the compressor fires up it would likely run from full charge to completely flat in around 10minutes with a single refrigeration unit (Spec: Full load 500W = ~5min with new batteries ?), that's probably something like a single cooling cycle .... unless you have a seriously large external battery array wired up ....

I'd expect that you'd need something like a decent spec datacentre, industrial or emergency lighting unit to run a fridge or freezer for a decent time, especially in this heat ....

HTH
Z