Although the grid situation in Switzerland is stable and the supply security is at no concrete risk, the grid operation in the alpine winter is usually strained and challenging for TSC member Swissgrid, the Swiss transmission system operator (TSO). This was especially true of the severe winter of 2015/16 and is one more reason for Swissgrid to accelerate the grid extension in Switzerland according to “Strategic Grid 2025”, the TSO’s ambitious grid modernisation and expansion plan.
An important part of “Strategic Grid 2025” is the upgrade of the electrical substation Beznau in the Swiss Canton of Aargau including a new 380/220 kV transformer. After the Swiss Federal Inspectorate for Heavy Current Installations (“Eidgenössisches Starkstrominspektorat”, ESTI) had approved Swissgrid’s upgrading plans in July 2016, the preparatory work in Beznau started immediately. In November 2016 and January 2017 the transformer was delivered to Beznau in three segments via heavy-duty transport. After some test runs the new transformer has now been put into operation.
The new device – situated on an island in the middle of the river Aare in Beznau and operated by Axpo Power AG – is not intended for operating constantly but as a backup for critical grid situations. Hence it is designed to be activated by Swissgrid on short notice. The transformer supports import capacity in the northern Swiss border region and improves the supply security in metropolitan area of Zurich.
> See Swissgrid press release (html)