DC for Ev stations

This has been going on for quite some time. What's more important to consider is that electrical separation is often involved - IT system on the DC side, in some of these cases, from the [rectified] output of the transformer onwards.

IT systems are new to the filling station environment, and this is treated in the EV CoP/Blue Book supplement for EV charging at filling stations.

DC ultra-fast chargers have multiple spaces instead of the usual two

Nice idea - certainly useful where you have lots of spaces but only a few vehicles that need a rapid charge at any given time. I can see it struggling where there are lots of vehicles wanting a rapid charge at the same time (e.g. motorway services or supermarket carparks) and can't really see the advantage over multiple relatively simple a.c. charger points where vehicles are likely to be parked for a significant length of time (e.g. overnight at hotels), but certainly useful for some niche situations.

The cabling could well be interesting - presumably it'll have to be quite chunky to satisfy sensible voltage drop requirements at that sort of power, and a lot of it to feed multiple bays.

   - Andy.

AJJewsbury said:

Nice idea - certainly useful where you have lots of spaces but only a few vehicles that need a rapid charge at any given time. I can see it struggling where there are lots of vehicles wanting a rapid charge at the same time (e.g. motorway services or supermarket carparks)

Andy, yes you'd think - the transformers being installed to power "a few charging points" in this way at filling stations or motorway services are in the MVA ratings order of magnitude ... but it is happening, these are being installed, with larger or multiple transformers for motorway services.

And there’s me thinking some of these EV charging stations in service areas have dirty great big diesel gen sets in containers around the back.

A related problem is the transformer losses - in some cases this favours what looks like an inefficient solution, of 2 transformers stepping down from HV either the same size or one large one small, so that one can be totally disconnected when load is low. Other even odder ideas, like battery banks at the charging hubs to smooth the load over 24 hours or longer are also a serious consideration.

It is a new and strange problem, and the best right answers are very much work in progress.

Mike.

Sparkingchip said:

And there’s me thinking some of these EV charging stations in service areas have dirty great big diesel gen sets in containers around the back.

Now I wouldn't joke ... but perhaps not in the UK [hopefully ... ]

Unfortunately it is more common than one would imagine, " out of site and out of mind" so packaged diesel genset away from the charging facilities powering the EVSE until the DNO/IDNO can provide the dedicated supply.

Also it was known and a few newspapers run with the story that during C.O.P.26 last year, many of the V.I.P delegates stayed at the Gleneagles hotel in Perthshire and if you know the general area its quite remote and a overhead distribution network. Of course all these delegates travelling to the Conference venues had to be seen in EV's and not I.C.E vehicles, so a number of EV chargers were temporary installed at the hotel, issue was no spare capacity!! for the load, so yes you guessed it packaged gensets brought in, screened off to provide the power for the EVSE, 

I wont ask the moral question if that was the right thing to do or not.......................

GTB 

Well according to this fact checking piece it was biodiesel so not perhaps quite as bad as the fermented dinosaur the rest of us are burning..

www.politifact.com/.../

However it is amusing and does highlight a very real problem that the HV as well as LV infrastructure is not really man enough for an all electric vehicle fleet in all  parts of the country.

I could foresee a lot of 11kV lines needing to be upped to 33kV to do this easily, or a lot of extra heavy cable needed.

Mike.

Perhaps COP could have been pedal powered

https://www.agreenerfestival.com/wp-content/uploads/pdfs/Power_Behind_Festivals_Guide_2013_V1.2.pdf

Or even for low levels of power - not vehicle charging I think...

https://info.uwe.ac.uk/news/uwenews/news.aspx?id=3882