Home › Guides

Chinese GB test reports vs IEC 60076: what a buyer should know

Buyers often ask for an "IEC certificate" for a Chinese transformer. Most Chinese factories instead hold test reports issued under the Chinese standard GB/T 1094. It helps to know how the two relate.

GB/T 1094 and IEC 60076

GB/T 1094, the Chinese power transformer standard, is adopted from IEC 60076 and follows the same structure and test methods. A transformer built and tested to GB/T 1094 is tested in the same way as one tested to IEC 60076. The report, however, cites the GB number, not IEC.

Routine tests and type tests

• Routine tests are done on every unit before shipment: winding resistance, ratio and vector group, impedance and load loss, no-load loss and current, applied and induced voltage tests. You should receive these for your own units.
• Type tests are done once on a representative design, usually by an independent laboratory: temperature rise, lightning impulse, and sometimes short-circuit withstand. Factories share the report for the closest design.

Who issued the report

Look for a laboratory accredited by CNAS (China's accreditation body, a signatory of ILAC). Such reports are widely accepted. Check that the model and rating in the type-test report are close to what you are buying, and note whether short-circuit withstand was tested, as many reports do not include it.

When you need more

If your utility or consultant insists on a report that names IEC 60076, or on a short-circuit test, say so before ordering. It can be arranged but adds cost and time. Compact substations and switchgear are tested to IEC 62271; ask for those reports separately.