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10 May 2019

E.On embraces digital transformers across German distribution

E.ON said this week that it plans to install 2500 digital transformer stations in Germany at its four distribution grid operators – Avacon, Bayernwerk, E.DIS and Hansewerk – by the end of 2019. This is just the first slice of its distribution transformation – from now on it will only order digital transformers in Germany.

During the course of 2018 a number of digital transformer designs from companies like ABB and Siemens were launched, offering the primary functions of monitoring the smart grid and responding in real time to power fluctuations. E.ON seems to be taking a first mover status here and will likely integrate control of these functions into its grid management software.

One reason for this change is to maintain a balanced use of the grid, moving from central control of voltages with electricity then purely radiating out, towards more complex topologies where each stage in the journey of electricity can push power in multiple directions at once.

We asked E.On if it had decided yet on its equipment partners for these digital transformers and have not received a reply as yet. Many of the new designs of digital transformers focus purely on introducing control in the downstream part of an electric grid for the first time. Some others we have come across behave more like a router, with power able to be split in multiple directions, to facilitate more sources of energy, more distribution points, and energy trading at a lower level on the grid, complete with transactional reporting.

We came across one UK player the Faraday Grid, which claims to turn transformers into something resembling to a router, and allows electrical energy to flow in either direction, across any particular route to any destination. It is coupled with a blockchain based audit trail and can accommodate a huge amount of renewable energy. This is at the testing stage in the UK.

The key to any of these systems is having centralized access to data about what’s happening on every step of the journey electricity takes from the generation plant to the customer – not matter how complex that route is.

To ensure security of supply, voltage fluctuations must be kept within narrowly defined limits and the current flow must not exceed a specified value and to manage this, digital technology is likely to become essential. But beyond that, systems like eMobility will require accounts to be accessed from multiple points in a network, and for flexible authentication and data channels to support this.

Future digital transformers need to be able to independently control output voltage, input voltage, maintain frequency, maintain target power factor, remove all harmonics and maintain balance between phases. This would make a number of other technologies such as transformers, tap changers, StatComs, harmonic filters and capacitor banks redundant in grid design.