Power transformers

If we want to get the energy from the power plant to the fusebox into your home, the energy has to travel a long way through the network. Energy is transported above ground via conductors via high-voltage lines. In nature reserves or urban areas, this also happens with underground cables. Energy transport via high voltage offers a high transport capacity and little transport loss. In the national high-voltage network, we have voltage levels that vary from about 50 to 380 kV. To connect electrical networks of different voltage levels and to transport power with little loss, you need transformers and distribution stations. An important property of a transformer is that it has a high efficiency (approx. 99.5%) and therefore there is almost no power loss during transport.

A transformer is an electrical converter that can convert the voltage and current from low to higher (step-up) values ​​or vice versa (step-down) at constant frequency, with the aim of transporting power.

A three-phase power transformer is made up of three-phase high and low voltage windings (so-called short-circuit losses, I2R) that are each galvanically separated from each other and convert the voltage and current through the magnetic gaze package (so-called no-load losses). This whole is also called the active part of the transformer. In order to be able to absorb the voltage fluctuations in the network, the transformer is usually equipped with a control switch that can adjust under load. When the entire active part is ready, it is placed in a drying oven for some time to remove all invisible moisture from the insulation paper and wood. After this process, it is placed in the transformer tray and the tray is filled with transformer oil. This can be inhibited (with additives, antioxidants) or uninhibited (pure mineral oil) transformer oil and functions as an insulating and cooling medium offering excellent resistance to moisture.

Following an investigation by the EU Commission into the environmental and economic aspects of a transformer, regulation No. 548/2014 of the EU Commission of 21 May 2014. “In 2008, the total losses of the transformers in operation in the EU27 were 93.4 TWh. The potential to improve cost-effectiveness through more efficient design is estimated to be around 16.2 TWh per year by 2025, which equates to 3.7Mt of CO2 emissions, ”this regulation says. For this purpose, the maximum permitted no-load and short-circuit losses or the peak efficiency index (PEI) of a transformer has been determined for the medium-sized, and only the PEI has been determined for large power transformers. This regulation took effect on July 1, 2015 for the first phase and in the second phase a reduction of the no-load and short-circuit losses will take place, or an improvement in PEI and will take effect on July 1, 2021. Batenburg Energietechniek has represented Kolektor Etra's power transformers since 2007 on the Dutch market. Kolektor Etra produces transformers up to a capacity of 500MVA and a voltage of 420kV.

Curious about our projects with power transformers? View it on the digital project map of Kolektor Etra.

Or read more about the projects with power transformers from Kolektor Etra for Offshore here:

Power transformers for offshore