Tag:transformer=main

transformer = main
Description
A power transformer that forwards power between different voltage grids inside a substation.
Group: power
Used on these elements
Requires
power=*
Useful combination
operator=* frequency=* phases=* rating=* voltage:primary=* voltage:secondary=*
Status: approved
transformer=main $1% $1% $1% $1% More details at taginfo More details at taginfo
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Main transformers are forwarding power between different parts of a substation.
That kind of transformer are found in substations only.

Most of their capacity is dedicated to power forwarding between different voltages, opposite of auxiliary which feed local substations or premises only.

See power=transformer to get complete guidelines to map them.

Examples

Photo	Location	Tagging	Note
	Germany	power=transformer transformer=main location=outdoor voltage:primary=380000 voltage:secondary=110000 voltage:tertiary=20000 manufacturer=Alstom phases=3 windings=3 frequency=50	Large outdoor main power transformer in a transmission power substation
	France	power=transformer transformer=main location=outdoor voltage:primary=225000 voltage:secondary=63000 voltage:tertiary=10000 windings=3 windings:primary=1 windings:secondary=1 windings:tertiary=1 phases=3 frequency=50 rating=70000000	This transformer has 3 windings operating at 3 different voltages. 225kV side is on the foreground while 63kV is hidden at the back Tertiary winding is dedicated to 10kV, certainly for auxiliary services including transformer cooling system
	France	power=transformer transformer=main location=indoor voltage:primary=225000 voltage:secondary=20000 windings=2 windings:configuration=star windings:primary=1 windings:secondary=1 phases=3 frequency=50 rating=70000000	This plate can be seen on transformer themselves (picture taken with power grid operator acknowledgement) and gives the windings configuration with several other figures. All tags can be defined with it. Upside schema on the left informs us that all windings (A, B, C and a, b, c) are connected to neutral point (N), which match the IEC 421-10-01 of star connection definition. 70 MVA rating is taken from the last column of the left table.
	France	power=transformer transformer=main voltage:primary=63000 voltage:secondary=20000 windings=2 windings:primary=1 windings:secondary=1 phases=3 frequency=50 location=outdoor rating=20000000
	France	power=transformer transformer=main voltage:primary=20000 voltage:secondary=15000 windings=2 windings:primary=1 windings:secondary=1 windings:auto=yes phases=3 frequency=50 location=outdoor	Such transformer are used in France to feed legacy 15kV distribution zones from current 20kV infrastructures. Visible sign show us operational voltages of both sides and that the transformer works as an auto-transformer.
	France	power=transformer transformer=main voltage:primary=225000 voltage:secondary=50000 windings=2 windings:primary=1 windings:secondary=1 phases=2 frequency=50 location=outdoor	High speed rail lines are fed from transmission power grid with such biphase transformers. More information about French 50kV traction system on this chart They are located in a substation=traction substation fenced perimeter.
	France	On one of each transformer inside of the substation power=transformer transformer=main voltage:primary=-25000 voltage:secondary=25000 windings=2 windings:primary=1 windings:secondary=1 windings:auto=yes phases=1 frequency=50 location=outdoor	Due to pretty long distances, high speed rail 25kV contact lines have to be regularly fed by auto-transformers which take power from a -25kV feeder line going along railways. They are located in a substation=traction substation fenced perimeter.
	France	man_made=street_cabinet street_cabinet=power power=substation substation=minor_distribution transformer=main voltage:primary=20000 voltage:secondary=400 operator=Enedis phases=3 frequency=50 location=green	A simple substation (see POSTE meaning substation in French) can contain a single transformer with a very few equipment. This can be mapped in OSM as a node and then use substation=* and transformer=main simultaneously.