# Yy6 transformer connection reference

Canonical URL: https://eloragrid.ai/symbols/iec-yy6-transformer-connection-reference
Publisher: Elora Grid
Updated: 2026-10-14
Lookup label: Yy6
Drawing use: SLD, Schematic
Reference families: IEC, Manufacturer

## Symbol convention

Convention: IEC
Form: Yy6 transformer connection reference
Autodesk IEC-60617 Symbol Preview — Three-phase transformer and vector-group forms; vendor family reference, not certified IEC geometry or database identifier.

This reference identifies the publisher's Yy6 transformer connection form with star/star winding topology.

## What it represents

Yy6 combines an HV-side star winding designation with an LV-side star designation and clock group 6. The letters describe connection topology; the final number identifies the phase relationship recorded with the transformer connection diagram. It is different from the voltage ratio or the number of terminals.
A drafter should preserve the full Yy6 designation across the SLD, transformer schedule and protection references. Even when both windings use star topology, the clock-group information remains a separate part of the connection designation. Check the selected transformer terminal diagram and the protection application documentation; the concept preview does not specify polarity tests, parallel-operation suitability or relay settings.

## How to read it

- Preserve the full group notation and verify the terminal/phase relationship in the selected transformer diagram.
- The clock-group suffix is different from a voltage ratio, power rating or physical terminal number.

## Information to show or reference

- Identify the associated device, circuit or diagram boundary.
- Preserve the full group notation and verify the terminal/phase relationship in the selected transformer diagram.
- Cross-reference the equipment data, terminal mapping or operating-state legend needed to interpret the form.

## Important distinction

The clock-group suffix is different from a voltage ratio, power rating or physical terminal number.

## Facts

- Reference scope: Specific public IEC-context family form
- Publisher reference token: HXF1T24 (Autodesk token; not a verified IEC database ID)
- Information added: Preserve the full group notation and verify the terminal/phase relationship in the selected transformer diagram.
- Preview: Independent educational concept; consult the publisher and applicable standard for the exact graphic
- HV winding topology: star
- LV winding topology: star
- Clock-group label: 6

## Public references

- [AutoCAD Electrical: Three-phase transformer connections](https://help.autodesk.com/cloudhelp/2021/ENU/AutoCAD-Electrical/files/GUID-EB13DB13-01EE-4541-BED7-19B9001BE8FC.htm) — Autodesk. Official public publisher family name and reference context; vendor identifiers and graphics are distinct from licensed IEC database content.
- [Transformer vector-group interpretation in protection application](https://techdoc.relays.protection-control.abb/r/SSC600-and-SSC600-SW-Technical-Manual/1.5/en-US/TR2PTDF-Operation-principle?contentId=_tVeRElk4P5wHpFgF2sYvw) — ABB. Manufacturer application context explains why winding type and clock number must be kept distinct in transformer protection documentation. No relay settings are prescribed here.

## Graphic scope

Independent original educational concept illustration by Elora Grid. Not a certified standards graphic or manufacturer footprint. Unitless; not to scale. Original artwork licence: https://creativecommons.org/licenses/by/4.0/. Publisher material is linked only.