Several tests according to IEC 60076 Standards were performed in July 2023 on two three-phase oil-immersed autotransformers 400 MVA 400 / 155 kV and 600 MVA 400 / 230 kV at GETRA factory placed in Caserta (Italy) by LCOE technicians.

LCOE measurement equipment, including measuring instrument transformers, power analyser and sound-meter, were displaced to GETRA factory to perform on-site the following tests according to IEC 60076-1 and IEC 60076-10 Standards.

• Measurement of windings resistance at ambient temperature.

• No-load losses measurement at 90%, 100% and 110% of rated voltage.

• Measurement of load losses at rated current for rated tap 155 kV for Transformer 1 and 230 kV for Transformer 2, including the calculation of load losses and the total losses at reference temperature 75 ºC.

• Measurement of the electrical power of the OFAF cooling system for PEI calculation, including all air fans and oil pumps of the units.

• Determination of sound power level at rated voltage according to IEC 60076-10 Standard by using weighted sound pressure method.

The generation system of the factory was used to apply the required test voltages and currents to carry out the tests and the LCOE test results were compared with the measurements of the manufacturer, obtaining very similar results with deviations lower than 2-3 % for the measured losses.

All tests were witnessed by TERNA inspectors, final customer and user of the autotransformers for the Italian high voltage grid, and the presence of LCOE, as an independent entity, was required to verify the rated characteristics of the transformers and compliance with TERNA technical specification.

For additional information:

Tomás García tgarcia@ffii.es & Paula Cid paula.cid@ffii.es