The evolution of power transformer

110 years of power transformer technology

ABB built one of the first power transformers in 1893 and remains market leader – in terms of market share, installed base and technological innovation – to this day.

The first of many firsts

ABB built its first three-phase-transformer for the very first commercial power transmission with alternating current (AC) in 1893. The transformer and the three-phase system were crucial innovations in power transmission and they made ABB a natural choice when Sweden and other European countries began to build their electricity and industrial infrastructures in the coming decades.


Transformer are tailor-made solutions.
ABB has more than 100 years experience.

Examples: 1891 - 1941- 2003


























Although there were significant ABB innovations in the first half of the 20th century, such as the world’s first self-cooling transformer in 1932, it was not until the 1950s that transmission technology made large and rapid strides.

Long-haul transmission and higher voltages

In 1952 ABB built the first single-phase transformer for 400 kV transmission, and quickly followed it up in 1954 with the world’s first high voltage direct current (HVDC) transmission. Thanks to these two innovations, the transmission of high voltages over long distances was now possible. Progress was fast. Voltage ratings jumped from 400 to 500 to 800 kV, and three-phase ratings rose tenfold from 100 MVA to more than 1000 MVA. ABB was leading this development and power transformers were a key element in the technology.

R&D muscle

By the 1970s ABB was in a position to build the prototype of what is still the one of the biggest transformers ever constructed. Built on behalf of American Electric Power, the transformer had a rating of 1785 kV and was successfully operated as a prototype at a test facility near Chicago. By comparison, the highest voltages of commercially installed transformers today are 800 kV (with the exception of a 1050 kV line in Russia).

From Itaipú to the Three Gorges

When the Itaipú Dam in Brazil was opened in 1982, it was the biggest hydropower project in the world, with a generating capacity of 12,600 megawatts. It was also the biggest HVDC project ever, designed and engineered by ABB, with a voltage rating of 600 kV, the highest anywhere. Twenty years later Itaipú has been surpassed in size by the Three Gorges project in China which, when completed in 2009, will have a capacity of 18,200 megawatts. ABB is supplying the two HVDC links – the first went online in 2003, the second is scheduled for 2004 – including 14 converter transformers for the converter stations. ABB has won orders worth US$ 1 billion for power transmission products and systems for the Three Gorges.

“Intelligent” transformers

ABB´s latest innovation is Transformer Electronic Control (TEC).
Today every new transformer could be equipped with TEC.
As of 2004 all ABB power transformers will include TEC, a solution that assesses the condition of the transformer system and makes intelligent recommendations based on design and component data. The electronic control system increases availability, reduces maintenance costs and extends transformer life.


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    What is a power transformer?

    • The transformer adjusts the voltage to a suitable level on each leg of power transmission from generation to the enduser. This means stepping up the voltage at generation for long haul transmission with low losses and down to domestic voltage manageable in the power outlet for home and industry.

    The creation of power transformer

    • ABB designs and manufactures some 1300 power transformers a year, for all voltages and applications, at 22 focused factories all over the world.

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