GB/T 1094.11 and IEC 60076-11: checking a dry-type transformer report

Identify the tested transformer

Request the complete report, including its cover, model schedule and conclusions. Check the laboratory, report holder and page sequence. Record rated power, voltage ratio, tapping range, frequency, insulation level, cooling method, winding material and enclosure condition beside the offered values.

Where values or construction differ, ask the manufacturer for a written explanation with the relevant design rule, calculation or additional test. Identify both the tested model and the offered model in that response.

Check the standard edition

This note refers to GB/T 1094.11-2022 and IEC 60076-11:2018. Confirm the edition used by the laboratory and the edition required by the contract, including applicable amendments, corrections or interpretations. For an older report, ask the supplier to list the differences that affect the offered transformer and identify the supporting documents.

Find the classification and enclosure records

For specified climatic, environmental or fire classes, request the declaration and the relevant classification reports. Temperature-rise and dielectric reports address different characteristics. If a classification is outside the submitted report scope, ask what further substantiation is required before approval.

An enclosure also affects cooling. If the tested unit was open and the offered transformer is enclosed, request the ventilation arrangement, heat-dissipation assessment and design ambient temperature.

Resolve rating and frequency differences

For a 60 Hz project supported by a 50 Hz report, request the assessment of core flux, losses, temperature rise, impedance and sound for the offered design. Apply the same report-to-offer check when power, voltage ratio or winding material changes.

Keep the response in one comparison sheet: tested value, offered value, supporting report or calculation, and any remaining action. Add page references so the project engineer can review each difference.