{"schemaVersion":1,"slug":"iec-yd11-transformer-connection-reference","name":"Yd11 transformer connection reference","kind":"symbol","abbreviation":"Yd11","aliases":["Yd11 transformer connection reference symbol","HXF1T25","Yd11 transformer connection reference IEC reference"],"category":"power-distribution","drawingTypes":["SLD","Schematic"],"referenceFamilies":["IEC","Manufacturer"],"summary":"This reference identifies the publisher's Yd11 transformer connection form with star/delta winding topology.","description":["Yd11 combines an HV-side star winding designation with an LV-side delta designation and clock group 11. 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 Yd11 designation across the SLD, transformer schedule and protection references. Two devices with the same winding letters but a different clock number are not the same connection reference. 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."],"readingNotes":["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."],"drawingChecklist":["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."],"distinction":"The clock-group suffix is different from a voltage ratio, power rating or physical terminal number.","facts":[{"label":"Reference scope","value":"Specific public IEC-context family form"},{"label":"Publisher reference token","value":"HXF1T25 (Autodesk token; not a verified IEC database ID)"},{"label":"Information added","value":"Preserve the full group notation and verify the terminal/phase relationship in the selected transformer diagram."},{"label":"Preview","value":"Independent educational concept; consult the publisher and applicable standard for the exact graphic"},{"label":"HV winding topology","value":"star"},{"label":"LV winding topology","value":"delta"},{"label":"Clock-group label","value":"11"}],"references":[{"sourceId":"pub-symbol-three-phase-transformers","relevance":"Official public publisher family name and reference context; vendor identifiers and graphics are distinct from licensed IEC database content."},{"sourceId":"iec-public-vector-interpretation","relevance":"Manufacturer application context explains why winding type and clock number must be kept distinct in transformer protection documentation. No relay settings are prescribed here."}],"related":["power-transformer","voltage-transformer"],"artwork":"edu-iec-yd11-transformer-connection-reference","publishedOn":"2026-10-14","updatedOn":"2026-10-14","provenance":"independent-public-research","symbolVariant":{"convention":"IEC","form":"Yd11 transformer connection reference","reference":"Autodesk IEC-60617 Symbol Preview — Three-phase transformer and vector-group forms; vendor family reference, not certified IEC geometry or database identifier."},"url":"https://eloragrid.ai/symbols/iec-yd11-transformer-connection-reference","illustration":{"url":"https://eloragrid.ai/library/illustrations/iec-yd11-transformer-connection-reference.svg","scope":"Original educational concept; not an official standard graphic or product footprint","license":"https://creativecommons.org/licenses/by/4.0/"},"sources":[{"id":"pub-symbol-three-phase-transformers","title":"AutoCAD Electrical: Three-phase transformer connections","publisher":"Autodesk","url":"https://help.autodesk.com/cloudhelp/2021/ENU/AutoCAD-Electrical/files/GUID-EB13DB13-01EE-4541-BED7-19B9001BE8FC.htm","type":"cad-reference","scope":"Public vendor catalogue naming and functional variants. Vendor block names are not IEC identifiers. Linked for reference; no graphics or CAD files are redistributed.","checkedOn":"2026-10-13","reuse":"link-only","relevance":"Official public publisher family name and reference context; vendor identifiers and graphics are distinct from licensed IEC database content."},{"id":"iec-public-vector-interpretation","title":"Transformer vector-group interpretation in protection application","publisher":"ABB","url":"https://techdoc.relays.protection-control.abb/r/SSC600-and-SSC600-SW-Technical-Manual/1.5/en-US/TR2PTDF-Operation-principle?contentId=_tVeRElk4P5wHpFgF2sYvw","type":"manufacturer","scope":"Public manufacturer technical context distinguishes transformer winding types, clock numbers and measurement compensation. Used for interpretation, not to supply protection settings or a standard database graphic.","checkedOn":"2026-10-14","reuse":"link-only","relevance":"Manufacturer application context explains why winding type and clock number must be kept distinct in transformer protection documentation. No relay settings are prescribed here."}]}