The installation of a new 380/220 kV transformer in Laufenburg (Aargau) is a further step in the renewal and expansion of the substation in Laufenburg. The project is part of the «Strategic Grid 2025» and plays a key role in the Swiss transmission grid.
In 2017, the outdoor switching substation installed in the 1960s was replaced by a modern gas-insulated indoor switching substation in order to ensure security of supply in the future as well. The existing 380/220 kV transformer installed in 1966 has now also reached the end of its possible operating life and needs to be replaced. The new transformer will increase the transformer output from 600 MVA to 800 MVA so that the Swiss population can be supplied reliably in the future, even if there is an increased demand for electricity.
Innovative design and improved security measures
The new 800 MVA transformer will be installed next to the existing transformer and equipped with new connections to the 220 and 380 kV plants. Concrete walls surround each pole and provide space for the connections of all the poles. Only three of the four poles are ever in operation at the same time. And thanks to the existing connections, the reserve pole can be activated very quickly. There are plans to replace one active pole with the reserve pole every five years. This means the operating life of the transformer can be increased from approx. 45 years to at least 60 years.
As well as the installation of the transformer, the accompanying protective measures are also of a very high standard. In addition to the surrounding fire walls, a sprinkler system has been installed. The water for this system comes from a specially built 800m3 water reservoir located directly in the substation.
Transportation of the leviathans to Laufenburg
The four transformer poles were manufactured by Siemens Austria at its plant in Weiz. The poles were first transported by train to Linz, then by ship along the Danube, the Main and finally on the Rhine to Auhafen in Muttenz near Basel. Despite the low water level, all transformer poles reached Auhafen in Muttenz on time.
A special transport vehicle with twenty axles transported the approx. 200-tonne poles individually from the port to the Laufenburg substation. An entire day was needed to prepare and load the vehicle for each pole. The transportation of all four poles to the substation took about three weeks. During this time, sixteen trucks brought additional material for the installation of the transformer from Austria to Laufenburg. It will be commissioned in mid-2019 and will then replace the existing 600 MVA transformer.