Proposal talk:Transformers classification refinement

Should we completely replace transformer=distribution with transformer=minor_distribution?

Resolved: No, transformer=distribution isn't required to be replaced thanks to transformer=main

Currently, transformer=distribution is preserved for stand-alone transformers only as to limit the amount of edit to be made in case of approval.
94k features would be impacted by any change on this particular value.

However, this won't prevent to look for transformer=distribution and substation=minor_distribution to find all points feeding individual consumers. It mixes distribution and minor_distribution.

We could then introduce transformer=minor_distribution for stand-alone transformers only feeding individual consumers, which is longer and requires to edit already existing 94k features.
A decision should be made here Fanfouer (talk) 21:05, 9 August 2021 (UTC)

By introducing a new transformer=minor_distribution I think you introduce the same issue and confusion as existed before. Mixing components tagged according technical characteristics with their use or network topology. Allow the existence of transformer=distribution as preserved for for stand-alone transformers only is OK but should discouraged. transformer=main is preferred for future use, where the topology or use is either determined by the mapped network or by adding a substation=*, as the transformer, being even stand-alone is used as a substation, being it for distribution or minor_distribution. The transformer itself is a technically tagged component, just like f.i. a pole. Then introducing transformer=minor_distribution is not necessary. Keep technical and topology tagging schemes clearly separated and co-exist, even on same nodes. Bert Araali (talk) 16:47, 10 August 2021 (UTC)

Given problem is main, auxiliary are valid in substation context. If I say a transformer on top of a pole is a main one, main of what?

Proposed transformer=* doesn't mix topology and roles any more. Values are only roles and among them main, auxiliary, distribution are found. Do you agree with that? Fanfouer (talk) 17:01, 10 August 2021 (UTC)

It's not so much about agreeing or preference with the value, but rather the concept. I know, the transformer=main was introduced in a previous discussion we had and seemed a good choice. Good choice as we refer to it's construction as a "traditional" or "normal" construction, to have a better semantic term as just transformer=yes. This creates however another issue. F.i. auxiliary transformers might even be bigger then some transformer used for distribution, have the same traditional or normal construction. So the split technical and topology focused schemes might not be as strict as we wish or concluded. I would suggest to define a transformer=main as being a transformer of normal or traditional construction serving any kind of purpose outside the substation, or more easily, any transformer serving power outside the substation and not being of any of the specific types of transformers. Different from the substation=main which refers to a substation used to supply the main HV or MV network. To give you an extreme example where this can work: I once had a customer which has an electrolysis plant, consuming about 30% of the power of the main HV line. Essentially, being a consumer, individual, connected directly to the main HV line. How would you tag it's substation and transformer on the supply side ? A power transformer on or near or under a pole would just be transformer=main, with additional pole tags being mostly sufficient as identifying it as a transformer for distribution or minor_distribution services or by adding substation=minor_distribution to be more strict or easier to query seems to me viable. We should avoid any transformer values which existed in the previous version and causing much inconsistencies with the substation key. Thus a transformer tagging technically and technical use focused rather then usage oriented use as in distribution or minor_distribution which are topology concepts. I also think about transformers used solely for power factor compensation, do we consider them as auxiliary transformers or do we need transformer=compensator ? Glad to know your opinion about this. Bert Araali (talk) 18:54, 10 August 2021 (UTC)

transformer=* wasn't defined as transformer construction. Are you suggesting it should? Reply: No, but I have no good definition or suggestion to make clear transformer=* is more aimed at let's say technical use or implementation, substation=* more aimed at topology. Leave it as is unless we have some bright idea ?

Do we agree both main and auxiliary transformers have the same internal construction? Question is to relate to their role in a particular substation. The exact same transformer can be an auxiliary one in a facility and a main one feeding distribution grid in another else. Reply: I agree. transformer=auxiliary is for localised use within a substation, transformer=main (supply) and transformer=phase_angle_regulator (optimisation) for grid purposes, outside the substation.

Regarding your example electrolysis plant, substation would be tagged substation=industrial (like 147132682 147132682) and transformers with no particular value currently (see 2791896483 2791896483) but would be transformer=main I guess, no matter the substation is private or consumes 30% of HV line energy. Reply: True for the industrial consumer side, not for the supply side I was talking about. The substation at the supply side (located at a nuclear pant by the way) serves about 60% of industrial consumers, both HV and MV, some with dedicated HV lines, others mixed with residential or other LV consumers. Introducing transformer=minor_distribution could introduce some confusion here, so I am not a favourite of it. These mixed cases are quite common in industrialised areas.

It should be said OSM consumers don't decide to add substation=minor_distribution on a particular pole: undergoing proposal currently explains it has to be clearly signed as a substation by the power operator and it mainly depends on country practices. We're not supposed to find poles hosting transformers called substation in the USA for instance. Thus, it's not an option to make things clearer. Reply: I see. I don't see any issue though using transformer=main for these applications. Fits the description of the transformer, as to supply grid sections rather then any local use. Also keeping some variants in mind like switch cabinets and distribution panels nearby the transformer pole, which might be supplied by a separate auxiliary transformer or tertiary winding on the "main transformer". transformer=minor_distribution in my view makes the tagging unnecessary more complex and confusion with the similar tagged substations.

I'm open to enlarge the definition of main as transformers that serve power outside of their premises which would encompass both substations and simpler poles without enforcing the last with substation. Reply: +1

Finally, compensation transformers don't feed substation's internal services (definition of auxiliary). It's a particular role and you may be looking for transformer=phase_angle_regulator, mightn't you? Reply: True, uncommon name in my field. Probably that's why I initially overlooked it in my comment, sorry. Despite roles are consistent with topology, it's not necessarily redundant: they allow consistency checks between topology, voltages and other figures. For instance it's unusual to find transformer=generator with voltage:primary=* > voltage:secondary=* and is the only way to warn about such issues. Fanfouer (talk) 19:58, 10 August 2021 (UTC) Replies by --Bert Araali (talk) 17:08, 11 August 2021 (UTC)

Thank you @Bert Araali: for follow up and sorry for this little delay

Yes transformer=* will remains as a role description.

Regarding your industrial example, there are two possibilities: If there are two distinct substations, operated by different people or at least splited by a fence, you'll be able to use substation=industrial and substation=transmission respectively. If there is one single perimeter, operated by a single company, then substation=transmission prevails on substation=industrial.

The only point remaining in favour of transformer=distribution for standalone transformer is people seeking for distribution infrastructure without substation=distribution. I'm not sure they'll agree to look at voltage:secondary=* to filter transformer=main dedicated to final distribution purpose (while it can be accurate). Additional situation regards HV/MV transformer feeding distribution grid in larger transmission substations. They would be called main, just like HV/HV transformers and the only mean to distinguish them is to look at operator or secondary voltage. We need to take care of that. Fanfouer (talk) 11:20, 8 September 2021 (UTC)

The delays don't disturb me, it's rather supporting to have some new insights and solutions grow @Fanfouer:. The assignment of "use" tag values to substation, as you proposed for the given example is not incorrect, but rather an inaccuracy. I wouldn't restrict the "use" cases of substations to physical barriers like fences. Prevailing substation=transmission the same, not wrong but inaccurate. The alternatives are sparse and not preferred I guess, one could argue using multiple ";" separated values in substation=*.

Determining the "use" of a transformer by evaluating it's secondary voltage or operator may lead to the same issues, even worse wrong conclusions, I think about the ever growing number of micro and mini-grids where the operators are very diverse and transmission lines are on MV and even LV. When you analyse the issue more closely, one can soon come to the conclusion, that any transformer not contained within a substation is with great probability a transformer=distribution. Which, doesn't solve the issue for distribution transformers in a substation. Actually, I have done some reading on the use of OSM power tagging. Our data scheme seems to give quite usable and accurate results for HV. The data used is however the power relations and the lines or cables to determine a georeferenced topology of the grid. The "use" tags of both transformers and substations don't seem to be used at all. This acknowledges my professional experience.

Maybe we should be more bold and provide a more accurate scheme, one that also allows us to more accurately tag LV grids, mini grids and the fast changing use cases (local solar and wind generation feeding into the grid, EV charging stations etc...). A most interesting read about this is [[1]]. Maybe we should consider applying "use" or topology tags on individual line and cable tags. Any substation or transformer "use" would then be derived data and redundant, so should be discouraged for it's further use. I would rather see a more accurate technical tagging of transformers, f.i. as different single or three phase configurations as they greatly influence the grid as in stability, power density etc... . It does provide ability to be more accurate and conclusive about their actual, sometimes combined usage and eliminate inaccuracies and complexities which we face currently with the tagging of substation and transformer. As actually tagging "use" on the vertices rather then the nodes in a model (same as we do f.i. for road networks). I still have to find a line or cable (or sections of it) that have "use" cases that cannot be described with an accurate single value. How do you see this, would this be an option you and the broader community are open to ? --Bert Araali (talk) 16:45, 9 September 2021 (UTC)

I mainly got your point and agree with making our model more suitable for micro grids and I disagree about changes it would imply on transmission term's definition. In Europe, market competition drove some laws to be put into action to physically separate perimeters operated by several operators. Some of them even put different gravel color on ground to make the responsabilities clear and that's how we assign transmission and industrial or traction in some places. Can you provide use examples where ;-list for substation=* would be the most preferred solution please?

Power transmission is defined as bulk power transfer, traditionally at high voltage. Even if power plants are connected to a distribution grid, it doesn't make this network an actual transmission one, this is part of many continetal (I know european ones) regulation rules.

Refinement of substations functions has already been proposed but still refused, in particular this chart reflects what was intended.

By the way I currently fail to get from this discussion if we should completely drop transformer=distribution or not. It doesn't prevent us to make a more extensive use of usage=* (already including transmission, distribution...) on power lines but it's a different topic. Fanfouer (talk) 10:40, 10 September 2021 (UTC)

I've completed the substation=* documentation with guidelines on how to determine the OSM role. We can discuss it there if necessary. Fanfouer (talk) 14:54, 11 September 2021 (UTC)

Seek of consensus

@Kovposch: Is that ok for you ? Following comments on Substation nodes proposal.
Currently, no transformer=minor_distribution as to avoid retagging of ~94k features but transformer=distribution will be dedicated for stand alone transformers outside of substations, feeding local consumers, houseolds, wharever Fanfouer (talk) 00:08, 28 November 2021 (UTC)

Should be fine with transformer=main added. ---- Kovposch (talk) 04:13, 3 December 2021 (UTC)

You could have a problem with small service buildings and street cabinets that have a transformer node tagged inside.

Street cabinets and small buildings/cabinets that fit one person between the rows are quite common here in Norway and are 22kV or less with 415V and/or 240V output depending on if its TT, IT(most common) or TN(most new stations).

The inconsistency here is that the substation is "minor_distribution" and the transformer inside is then just "distribution". Gazer75 (talk) 22:54, 10 December 2021 (UTC)

This will be addressed in the further stage in this proposal. The transformer will become transformer=main since in an actual substation Fanfouer (talk) 23:37, 10 December 2021 (UTC)

Makes no sense to me. The transformer have the same task if its mounted out on a pole or inside a small box. The smallest of these cabinets are just large enough to fit the transformer and some cables as they might supply a couple of customers. Gazer75 (talk) 00:24, 11 December 2021 (UTC)

We should make an important distinction here. Both cabinets and poles aren't always an actual substation (a place where electricity is transformed, converted or switched with necessary controlgear) but can be somewhere. As of this proposal, a transformer=distribution is used stand alone outside a substation, with less monitoring and protective equipment than transformer=main inside a substation.

I kept transformer=distribution to prevent too much retagging as approx 70% of existing is used on top of a pole (which is assumed not a substation).

Consistently with main and auxiliary I could have chosen standalone instead of distribution, which leads to retag ~94k features.

If the box you discuss about is not a substation, no problem to use transformer=distribution with it as well, just like on top of poles Fanfouer (talk) 10:50, 11 December 2021 (UTC)

@Gazer75: this proposal may catch your attention Fanfouer (talk) 09:07, 2 December 2021 (UTC)

So are we then to change current distribution transformers to main? As in any that do not do below 1kV. I believe I've tagged transformer that "outputs" between 33 and 1kV as distribution, same as the pole mounted tagging. Gazer75 (talk) 01:51, 9 December 2021 (UTC)

It depends if those transformers are in actual substations or not (if they outputs 33 kV I think so). So yes, I guess Fanfouer (talk) 18:33, 9 December 2021 (UTC)

So basically any transformer that is not outputting 415/240V (Europe) will be main unless its auxiliary for substation supply. At least make the main value default so we avoid having unnecessary tagging. Gazer75 (talk) 19:59, 9 December 2021 (UTC)

It's okay to make transformer=main default, already in the proposal. We may miss a voltage_regulator (consistent with phase_angle_regulator) value regarding such things on poles as well, mightn't you? Fanfouer (talk) 23:34, 9 December 2021 (UTC)

I believe we can just use the compensator=voltage_regulator just as we use transformer=distribution for pole mounted transformers. Gazer75 (talk) 00:48, 10 December 2021 (UTC)

Nice one, thank you. I didn't remember we had it in power=compensator. Fanfouer (talk) 22:25, 10 December 2021 (UTC)

@M!dgard: @TagaSanPedroAko: This proposal could catch your attention as well Fanfouer (talk) 15:30, 29 January 2022 (UTC)

@Russss: following comment of @Jnicho02:, had you seen announcements about this proposal? Feel free to forward it to interested people Fanfouer (talk) 12:09, 9 February 2022 (UTC)

Looks good to me! I don't really use these tags for analysis at the moment, but minor_distribution always annoyed me a bit, and this seems like a solid improvement. --Russss (talk) 16:21, 10 February 2022 (UTC)

Should we use usage=transmission or usage=distribution on transformer to distinguish them?

Resolved: Yes we can, outside the scope of the proposal

Some transmission substations also have some equipment dedicated to distribution without any clear separating fence between them and the rest of the transmission equipment. Transformers are particularly subject to this, although regulation rules encourage to install supplementary fences to separate spaces operated by different actors.
As it is proposed to introduce transformer=main which doesn't allow such a distinguishing, respective usage of usage=transmission and usage=distribution on corresponding transformers may be useful.
It's not a specific problem of transformers and usage=* is also suitable for other substations equipment. It would finally allow to have a comprehensive view of what is relevant for transmission or distribution in a shared facility (out of the scope of this proposal by the way). Fanfouer (talk) 11:41, 12 September 2021 (UTC)

Auxiliary transformers on poles

Resolved: Added to the proposal

It seems we can actually find auxiliary transformers on poles as to feed remote controlling logic of switches, like on the picture aside.
The transformer is under the switch, connected between two phases of the aerial power line.
As it's low rating transformers, size is really small but voltage different may be wide. Here it's 20kV on primary side and 230V on the secondary.
I think about allowing transformer=auxiliary on poles, opposite of transformer=distribution, dedicated to feeding operator's premises. Fanfouer (talk) 22:39, 10 December 2021 (UTC)

Compensator transformers

Static VAR compensators operate at around 7-8kV and will have a transformer between it and the rest of the grid. These could have its own transfomer=compensator tag as they are dedicated to this. Gazer75 (talk) 23:17, 9 February 2022 (UTC)

That's accurate, thank you. We indeed need kind of transformer=compensator as to not count their power rating in the whole substation capacity.

As the vote goes on, two possible solutions: add this value and necessarily restart the vote from the begining OR wait for a broader proposal on power=compensator with additional items we may need on the topic according to your experience? Fanfouer (talk) 11:32, 10 February 2022 (UTC)

Third solution: document this new value separately, add it to transformer=* possible values with in use status and review it later in a further proposal. transformer=main is already consistent as it covers transformers that forward power, no need to adapt it there Fanfouer (talk) 11:36, 10 February 2022 (UTC)

Auxiliary transformer

There are instances where they use a third winding on the main transformer to feed a smaller one for local use. Like a 420/132/22 where the 22kV goes to a 22/0.4/0.24 for local use. Is that just a main transformer even though the 22kV is for auxiliary use? Unless rating is given for each voltage it will include the 22kV part as well, which would be inaccurate if we want to find total transmission capacity. Gazer75 (talk) 15:52, 10 February 2022 (UTC)

Yes it is a main anyway. Rating of each interface could be given with rating:primary=*, rating:secondary=* and rating:tertiary=* if known. Tertiary interface use to have several magnitude orders lower rating than forward. Fanfouer (talk) 18:01, 10 February 2022 (UTC)