Image source: Hitachi ABB Power Grids

Hitachi ABB Power Grids installs TXpert™ digitalized transformer for Fortum

Sweden, Österdalälven: Fortum’s 120 m tall Trängslet hydropower dam in central Sweden is the country’s tallest hydropower plant.

With a normal annual electricity generation of 651 GWh, there can be no risk of breakdowns or generation stoppages.

The final 1,000 m of the dam’s access route is especially challenging, particularly in winter conditions, plus the electrical equipment is installed underground, via a narrow and steep tunnel.

“First and foremost, it is of course about being able to manufacture a transformer that meets our requirements,” says Mikael Andersson, project manager at Fortum Hydro. “It is difficult in terms of transport to get it here, and then adjustments are required to get it underground. As a manufacturer, you can not only offer a standard product, but you must spend time on design to meet our requirements.”

When one of the plant’s transformers began to show signs of being obsolete, Fortum acted immediately. The original transformer, which was also supplied by Hitachi ABB Power Grids (as ASEA), had been in operation for over 50 years and a one-to-one replacement was needed.

A 140 MVA and 155/16 kV TXpert™ enabled power transformer was selected, designed as a copy of the original unit. Hitachi ABB Power Grids’ TXpert™ transformers are equipped with digital devices to monitor and analyse the health of the transformer, enhancing reliability and performance.

The project included transportation plus on site installation and final assembly in this challenging location.

The one-to-one solution meant the transformer could be installed without costly electrical, mechanical or structural modifications. In fact, the new transformer is smaller than the old one because the modern technology requires less space, there is less oil in it and the losses are lower. Plus, the TXpert™ digital monitoring collects, compiles and analyses critical data to ensure that the transformer continuously delivers optimal performance.

The transformer operation in Trängslet is now secured and handed over to Fortum’s operations centre, remotely monitored and controlled 370 km away in Stockholm.

Fortum is one of the country’s largest hydropower producers, with more than 150 hydropower plants in Sweden and Finland. With a 70 km long reservoir, Trängslet in Österdalälven is one of Sweden’s largest hydropower plants.

Source: Hitachi ABB Power Grids