Power transformers – Efficiency, smart grids and the technical revolution


Power transformers are among the most important components of electrical grids: they transform electrical energy into various voltage levels, so that it may be transferred from power plants to high, medium and low-voltage lines, making it accessible to end users.

Transformers range from small to medium and large. In electricity distribution, medium and large transformers are used (with a capacity ranging from 50kVA to 63 MVA). Thanks to the Ecodesign Directive, these electrical machines (with an average 30 year life span) are headed toward a new era.

This was one of the issues that was discussed at the XIX Edition of CWIEME Berlin, the international exhibition of technologies and electronic, electrotechnical and electromechanical components from different sectors: from automotive to consumer electronics and the aerospace industry.

Enel Distribuzione was asked to participate in one of the event's seminars, with the aim to analyse the technical innovations and the development prospects of Regulation No. 548 / 2014 on power transformers, approved last year by the EU in implementation of the Ecodesign Directive (Directive 2009/125 /EU)

'Enel – explained Enel Distribuzione's Fulvio Mauri – was involved in the event due to two fundamental aspects: firstly, because it is among the most important European companies participating in the Ecodesign directive on a technical level. Secondly, it is involved in the European research project, Speed, whose objective is to develop and test a new concept of power transformers, which is more flexible and suited to the evolution of distribution networks in smart grids.'

Mauri is in fact the coordinator of Working Group 29, Energy performance of large power transformers, within CENELEC TC 14, the European Committee for “Electrotechnical Standardisation”, whose task is to define the industry's technical standards. He is also one of Enel's representatives, along with Angelo De Simone, from the Speed Project, an EU-funded initiative within the Seventh Framework Programme for Research, which involves several global leaders in power and automation technologies, and several European universities.

'The Ecodesign Directive – Mauri declared – is a regulatory framework, which was developed to protect the environment and reduce CO2 emissions and establish a set of technical specifications to increase the efficiency of machinery and/or devices that consume energy – from appliances and light bulbs to transformers. In 2014, the EU adopted a new regulation that specifically identifies minimum efficiency requirements for different types of power transformers that will be put on the market starting July 1, 2015.'

July 1st represents only the first step of the regulation, which will see an even more ambitious second phase in July, 2020. According to a study by the EU Commission, in 2008 the total annual losses suffered by the transformers park in the 27 EU countries amounted to 93.4 TWh. Improving the design of power transformers will save approximately 16.2 TWh per year and reduce 3.7 Mt of CO2emissions by 2025.

'The European project Speed – Mauri added – is developing a new concept of transformers which is no longer based on electromagnetic performance, but on power electronics, through the use high performance silicon carbide (SiC) semiconductors. Enel's role is to define the criteria of the new machines and test them in one of our facilities.' The new generation of transformers will feature a greater flexibility and will adapt to the development of smart grids for electricity distribution. The new transformers will contribute to grid voltage stability and maintain high quality power supply to customers.