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OPERATION EXPERIENCE OF THE POWERFORMER ( Generator without step up transformer)

Dr. Amal Khashab's picture
Expert Independent Consultant ,Electric Power Systems Engineering Free lancer

Summary Full Academic Qualification by obtaining B.Sc. (1971), M.Sc. (1980) and Ph.D. (1991) of Electric Power Engineering. Active continuous education by participating in long periods of...

  • Member since 2019
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  • Dec 6, 2021


( Generator without step up transformer)

- ABB launched in Zurich on 25 February 1998 a breakthrough with what it described as the "world's first high-voltage generator" called the PowerformerTM, It was said to be the first generator able to supply electricity directly to the high voltage network without the need for intervening transformers.

- In the new generator, round high voltage cables, using proven XLPE insulation technology, replace the complex structure of square-section insulated copper conductors that constitute the stator winding of a conventional generator.

- Powerformer can be sized to produce any output voltage. Step-up power transformers, with their associated cooling, are therefore no longer needed. High voltage connections are simplified and the layout can be made more compact (This is very important where space is scarce, for example underground power house).

- A prototype with a rating of 155kV, 75MVA was scheduled to be operating in May/June 1998, at the Porjus hydropower plant on the Lule River in northern Sweden, where it replaced one of the existing generators.

This plant was owned and operated by the Foundation Porjus Hydro Center, which was run jointly by Swedish utility Vattenfall, Kvaerner Turbin and ABB and serves as a development and training facility for hydropower technology.

ABB estimated that the fewer components used in the Powerformer system will improve efficiency by 0.5%, increase availability by 0.6% and reduce maintenance costs by 10% — an overall life cycle cost reduction said to be 30%.

- The first commercial installation and the first application of the Powerformer at a thermal power plant rated at 136kV, 42MVA, was scheduled to enter service at the end of 2000 at a CHP plant in Eskilstuna, central Sweden. The order, valued at about US$ 10 million, was placed by the Swedish utility Eskilstuna Energi & Miljö. Under the terms of the contract, ABB supplied a high-voltage generator, known as a Powerformer, and an associated steam turbine. The plant, fueled mainly by forest and sawmill wastes, had an output of 38 megawatts (MW) of electricity and 71 MW of heat, plus another 15 MW of heat recovered from the flue gases.

-The benefits of eliminating the step-up transformer include:

  • Life cycle cost (LCC) reduction of up to 30 percent: By reducing the size and number of components in the power plant, the Powerformer saves space, service and maintenance costs, reduces losses, and increases plant reliability

  • Environmental benefits: The Powerformer contains no oil, epoxy or other materials found in conventional generators that can create disposal problems.

  • The Powerformer reduces power losses and thereby increases overall energy efficiency.

  • It can also be used to connect small energy sources, like wind or small-scale hydro plants, to larger power grids.

- A comparative study was conducted in India to show how a Powerformer may affect the economy in hydropower project. The aim of the study was to use the existing hydroelectric power plant in India compared with a hypothetical plant with a poweformer. The annual electricity production is 3,200 gigawatt hours.

There are four turbines, four generators and 13 single-phase transformers. Four Powerformers are used to replace the four generators and the 13 single-phase step-up transformers. The total cost savings associated with Powerformers due to lower construction and maintenance costs were estimated at 24% in addition to the increase in power generation of 17 Gwh (0.56%).


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Dr. Amal Khashab's picture
Thank Dr. Amal for the Post!
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