[Tagging] [Power] sub_station vs substation

[Ole Nielsen]

On 09/11/2013 19:52, fly wrote:
> On 09.11.2013 18:35, bredy wrote:
>> But is not possible to convert all the old sub_station in substation? The tag
>> is same only correct.
>
> You should add a subtag if transferring.
>
> @François:
> Would you please better explain the values for substation= and maybe add
> some pictures.

+1
We should surely not make an automatic conversion of the tag. Keeping 
the old tag is useful for tracking substations that need reviewing.

Anyway, I (and not Francois) was the proposer of the substation proposal 
and as such responsible for the substation=* key. The main issue at the 
moment is whether we need a special value for the lowest level 
substations, those directly supplying household consumers with low 
voltage. I asked this question in another thread and got one suggestion: 
"local_distribution". I have since tagged a few substations with 
"minor_substation" as 'local' is a somewhat ambiguous term (I admit that 
could also apply to 'minor) but I haven't documented anything so far.

For substations that are not for 'special purpose' (such as converter, 
traction etc) the recommendation is to use the value 'transmission' for 
substations having a highest operation voltage above 100 kV and 
'distribution' for those below that voltage. There may be reasons to 
deviate from this rule but the average mapper having no special 
knowledge about a particular substation should stick to this rule.

Ole