In the UK, distribution transformers can be found inside what we would call “Substations”. They are ground mounted (padmount) transformers from 11kv to 400v and inside a small fenced off area, building or cabinet. They are common in urban areas where they are fed by an underground cable. It is incorrect to state that they are “Installed outside of any substation”. https://wiki.openstreetmap.org/wiki/Item:Q7682 The fenced off area can often be found in the Cadastral layer of the editor. The new version of JOSM has just flagged this up in the validation which I believe is incorrect
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Looking at the wiki pages, it seems that the intention there is to only use transformer=distribution for stand-alone transformers, and instead use transformer=main for distribution transformers inside substations. The level of the substation can then be specified with substation=distribution on the substation object.
That seems a bit odd to me, but maybe there are good reasons for doing so. Remember that OSM tags are just strings of letters that may or may not be defined to correspond exactly to the natural English meaning or the precise technical meaning of the words.
See:
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I am prepared to start adding substation=distribution on the new substation objects I create. However, a retrospective addition to the hundreds of distribution substations I have created would be a big task, (with much lower priority than adding new ones).
A distribution transformer transfers power from the distribution system to directly connected electricity consumers, so tagging it with transformer=main is not correct. It would also conflict with my use of a transformer=distribution node on its own, for a ground-based transformer where I am unable to map the fenced off substation area from cadastral or imagery layers.
Hello
An answer has been provided here: Talk:Tag:transformer=distribution - OpenStreetMap Wiki
I fully understand your comments and the disruption this update causes. The challenge we faced a few years ago was to find a consistent ontology for many different cases worldwide. A few tradeoffs were necessary.
We chose to completely send the distribution and traction concepts to the substation level and classify transformers among main, auxiliary, generator, converter and phase_angle_regulator.
It encourages to begin with the existence of a substation or not or to map transformers voltages.
Practically, depending on local contexts and practices, it may still be possible to set transformers as distribution ones with transformer=main + voltage:secondary=400.
I bet substation=minor_distribution is more appropriate for those cases.
I’m interested in this case. Why can’t you use the same node to put power=substation + substation=minor_distribution + transformer=main if you know there is a fenced perimeter or a cabinet without being able to draw its extent?
In the UK, is voltage:secondary=400 always the case, or could it be 240v? I have tended to leave it off in my work mapping the 11kv network based on WPD data.
I don’t practice UK enough to know, @Russ will definitely
I mostly map in Ireland and Northern Ireland. While consumer equipment is very similar to Britain, the generation and networks bits have their nuances. Power networks/Ireland - OpenStreetMap Wiki
I try to mark neighbourhood transformers as voltage:secondary=400;230 although most of the ones that I’ve mapped have been voltage:secondary=400 Adding the “;230” hopefully means that QA won’t moan about the wrong voltage being connected.
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These days, 220 V and 240 V are called 230 V and equipment is expected to be able to tolerate the difference. 380 V and 415 V are called 400 V.
As I understand this, in a normal transformer in an urban area, 230 V is achieved by using two (cables 1 and 2) of the three cables from a 400 V, 3-phases supply. Your neighbours down the road will a different pair (cables 1 and 3) from the three and the next street over will use the last pair (cables 2 and 3). Strictly speaking, the transformer only supplies a 400 V, 3-phases supply, but you get 240 V to your home. These transformers are typically rated at 200-600 kVA, that is you can have 100-300 kettles boiling at the same time. A new medium-sized housing estate or apartment block will get one of these.
In a rural area, pole-mounted transformers are much more common. Typically, these are much smaller and are typically cuboid in shape. I don’t know the ratings, but they tend to serve a cluster of maybe 10 houses or maybe a large farm.
Then at the lowest end of the scale, there are much simpler transformer that takes two medium-voltage wires and changes that to 230 V. These transformers are often, but not always cylindrical - I presume that means they have only a single coil. They tend to serve maybe 1-3 houses or maybe a house and farm.
Certainly in the case of NIE Networks, sometimes individual remote farms and businesses (and possibly houses) are supplied from the 33 kV network, as there might not be a 33 kV network within an economic distance. Look at all the green, 33 kV branches here: Open Infrastructure Map Unfortunately, I haven’t been able to work out how the 33 kV cables route through Rostrevor and Warrenpoint, hence the fragmented network.
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This is a medium-sized substation in Dublin. 38 kV comes in, 10 kV goes out: Way: Newmarket 38kV Substation (350602410) | OpenStreetMap However, this substation is slightly different, in that it also has a pair of 10 kV to 400 V transformers just inside the outer gate. These two transformers likely feed the buildings right next to the substation (the new buildings down the street have their own 10 kV transformers). While all three transformers are currently tagged transformer=distribution, the 38 kV one should probably be transformer=main. The other two should probably remain as transformer=distribution. I don’t recollect seeing a separate auxiliary transformer.
This appears to be a standalone transformer in Belfast. Either 11 kV or 6.6 kV comes in, 400 V goes out: Node: 14096929523 | OpenStreetMap Despite being in a kiosk, it is also on it’s own fenced-off site: Way: 1549913952 | OpenStreetMap I do not recognise it as a substation. The unusual 6.6 kV is likely a hangover from Belfast’s tram system.
Here, in Magheralin, 11 kV comes in, 400 V goes out: Node: 13473729376 | OpenStreetMap we have almost the exact same arrangement as Belfast, except we have a h-frame power=pole inside the fence and it’s an outdoor transformer, not in a kiosk. I do not recognise it as a substation.
Here, near Carrickmore, is an agricultural farm with a single wind turbine. Mostly wind comes in and 11 kV goes out: Way: 1539736207 | OpenStreetMap and here: Way: 1539736208 | OpenStreetMap we have a single, mid-sized wind turbine connected to a ‘box’ (likely contains controls, converter, possibly batteries) and a transformer in a kiosk. We have two fenced off locations. I do not see a power station. I do not see a substation. I see a wind turbine and two boxes.
There are certainly single-phase distribution transformers in the UK, but I suspect these are almost always pole-mount transformers in rural areas. As mentioned, they should technically be tagged as 230 V, not 240 V. If unsure, I’d leave the secondary voltage out. It’s not especially important.