Interview with Pascal Mueller, transformer expert at ewz
About ewz ewz is a Swiss utility engaged in the business of distribution and production of electric energy and communications services. It was established 120...
byTransformers Magazine
About ewz
ewz is a Swiss utility engaged in the business of distribution and production of electric energy and communications services. It was established 120 years ago and it is owned by the City of Zurich. As the second biggest distribution utility in Switzerland, it covers 50% of the Canton Grisons, and the City of Zurich. The peak consumption in Zurich is more than 500 MVA. For the grids in Zurich, in the mountains it operates several hydro, wind and sun power plants and cooperates with other companies for further power plants. ewz is focusing on renewable sources of energy.
The utility had a revenue of about CHF 790 million (USD 790 million) in 2014. It has almost 1,200 employees and about 225,000 customers.
ewz operates 29 substations with about 100 power transformers and step-up transformers. It has 16 substations in Zurich of 170 kV to 22 kV or 11 kV and four 220/170 kV. In three of them there are phase-shifting transformers used to regulate the power flow in the City of Zurich and between the main substations.
Grid technology drivers
At the low-voltage level of the grid, there is a general problem with energy production from renewable sources, which can significantly change electric parameters. Today, small transformers can be equipped with tap changers. This is one thing we have not started implementing as yet, but it is something that we have to think about. If we have long lines or a lot of production from alternative energy sources, then we may need such transformers.
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