I'm not sure what an 'outreach bed' is but I'm sure the bed they gave (loaned) my step-daughter earlier this year before she went into the hospice was battery equipped?
It was one of those that constantly inflated and deflated the mattress slightly to prevent bed sores and I know it beeped if you unplugged the main box bit (because we did whilst sorting it all out)?
Cheers, T i m
What's an outreach bed? The ones in the wards have batteries.
True, but I was thinking there could be something in between?
The idea was that you have the basic ballast in the real bilges (presumed fairly flat bottomed on yer average narrow boat) with an allowance for the batteries, potentially an inner tray, sealed from the bilge but still under the floor and vented directly to the outside (you don't typically need much freeboard on the rivers and canals).
According to the handout, 'Ampere' carries a working capacity of 48kW at 48V using 24 x 2V 'traction cells' that are 600mm deep (so may well go quite a way into the bilges as it is)?
Luckily, I don't suppose the 1.6 tonnes of batteries would even be noticed (weight wise anyway) in a 60+' narrow boat. ;-)
Cheers, T i m
Yes I've always thought this was bleedin stupid. It would be a trivial thing to have a set of deep discharge batteries and the inverter under manual control for just such an occasion. It is done in some less developed countries, no doubt a bit heath Robinson, but still. The current kit is really all about to same money and not add functionality. All I will say is that I have a friend who has hot water panels on the roof and although you cannot power the stereo or tv from it you can get hot water. The pump uses very little and can run on a small inverter you can pick up cheaply. Its a strange world we live in. Brian
No its trivial to fix it so that this does not happen in the event of a complete power outage. They either are more stupid than they seem or its just cost cutting. Brian
Isn't that an guesstimated 1/2 GW? As it's embedded in the distribution and not monitored/metered, all they see is a (slight) reduction in demand from their forecast. Probably well within the error bars of that forecast.
I don't think the loss of this embedded capacity is included in the offical figures for how much power the grid lost on that Friday.
It's not in the slightest trivial.
The solar panels are wired in series for about 500Vdc in full sunshine. How are you going to cheaply fix this?
Presumably the loss of embedded capacity would be shown by a matching increase in demand that we can see in some cases... (although not if the whole area has already been dropped)
I'm not asking why it is so, I'm stating that there is no/little resilience in commonly sold systems and I doubt that my neighbours would have had that explained to them.
Most people would not have expected to design a system for an 11.5hr power outage within a reasonably large city boundary.
An hour or two would not have been a problem.
Anyhow Western Power quite quickly hooked up an external generator which of course involved removing the household from the grid.
Thankfully someone realises there is a limit to the subsidies we have to pay.
No. they see an immediate and sudden drop as the frequency goes down. That is they will see a step change in DEMAND, upwards...
It's the size of the total step before load shedding
It's in either the OFCOM report or Kathryn Porter's - cant remember which or both..
Well it is included in it actually
....Three things then occurred almost simultaneously:
The reduction in generation from these events was:
737 MW ? Hornsea 244 MW ? Little Barford c 500 MW ? embedded generationThe cumulative amount of lost generation was 1,481 MW, 48% above the
1,000 MW single loss protection level at which the system was running at the time. (The system is designed so that it can continue to operate if the single largest generation unit trips at any time, which might be a large nuclear plant, or an interconnector.)"So yes it is an estimate, but in this case a pretty close one.
I was thinking under normal conditions. With the embedded stuff only showing up as a reduction in demand for a given area from the grids predictions, assuming said prediction doesn't make allowance for the embedded stuff. Which I expect it does, otherwise the margin will end up too big.
Ah that Lttle Barford figure has changed from what I remember. Must get aroound to reading the proper reports sometime...
I think that sbesequently Barford dropped its OCGT half - IIRC it is
480MW OCGT and 244MW steam...A shade under 2GW in all.
That's a lot of power for a narrow boat, 1 hp (approx 750 W) is all they needed orginally for propulsion. B-) Modern gadgets like electric lights, fridge, ain't going to add much more than 1 kW.
I suspect the common confusion between power (kW) and energy (kWHr). B-)
IIRC a 70' narrow boat has maximum payload of 60+ tons. So 1.6 is bugger all but will affect the trim. One wouldn't shove them all down one side or all at one end...
He is right they were the instantaneous drop-offs that occurred within the first seconds of the strike. In the case of Hornsea about 340ms from the transmission line protection circuit triggering.
The rest of Little Barford soldiered on for about a minute and then another unit tripped out followed by the third one 30s later (by which time load shedding had begun and the frequency was already rising).
The annotated frequency vs time diagram in the report is most enlightening. You want page 13 in this:
I don't think so.
You could have a complete parallel DC system in the house powering lights ?, special DC immersion heater and then an inverter for local 230VAC stuff but not mains connected.
That or a meaty UPS setup of some sort.
This defeats the main purpose of domestic PV panels though which is to milk the subsidies and you need to be on the grid to do that.
I have done this particular thing using a submersible solar powered pump that was intended to run a fountain with about 3m head of water pressure. It was programmed to run two slots of half an hour a day morning and evening to run hoselock drop lines in my greenhouse.
The original came from bankrupt stock as the solar powered fountain was distinctly unimpressive. Nothing wrong with the pump though when connected to a decent supply it packed quite a punch.
Only complication was it needed a stocking fine filter on the inlet otherwise mosquito larvae would jam the jets on the drip lines. Solar power wasn't a design win for it though - it was much easier to lug a charged 12Ah SLA battery up to the greenhouse and swap it as needed.
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