2017/11/23

Phase-angle displacement, optimum distribution and no overload on the grid: Transformers made by Royal SMIT control the voltage ratios within the Bavarian grid belonging to TenneT

For now, the scenario is still a dream of the future: You travel by car to your holiday destination and rely on its autonomous features as usual. However, as soon as you take the southbound motorway, you can already see the traffic jam ahead. You are in doubt about the performance of the autopilot, but then you are surprised to see the traffic jam disperse at precisely the right moment. This is because the networked computers of the cars in front of you have distributed the flow of recreation seeking tourists onto alternative routes, ensuring that each route to the South is optimally utilized, but not overloaded. For private transport, this scenario is still many years ahead, but it is already reality in power distribution. This is demonstrated by the new transformers delivered by the Dutch member of the SGB-SMIT Group to TenneT in their substation at Irsching (Vohburg an der Donau) at the end of August.

These two “direct-coupling transformers with phase-angle displacement” at the Irsching substation connect the 380 kV grid belonging to TenneT to the regional 110 kV grid operated by Bayernwerk. However, these two transformers do not only connect, but also regulate: Designed as phase shifter transformers, they are capable of "directing" the current flow of several lines. Thus it is possible to permanently and reliably avoid overloads in the underlying 110 kV grid. This double function was enabled by innovative circuitry technology: For the first time, Royal SMIT has combined an on-load tap changer with an “Advanced Retard Switch” (ARS) for TenneT. Such an ARS is capable of reversing the control voltage of phase shifter transformers - and this within a wide range. The two transformers for Irsching are 300 MVA transformers, but can easily manage power peaks up to 380 MVA.

Pioneering technology, a new transformer design and the ability to intervene into the power grid with a regulating capacity: these features have made the two transformers flagships for Royal SMIT and the entire SGB-SMIT Group. And being - in the full sense of the word - heavyweight ambassadors for the motto “Your dedicated partner”, they have attracted a lot of attention on their way to the customer ... meaning that each of these transformers has a remarkable weight of 275 t – without oil and attachments which will subsequently add up to a total weight of 438 t for each transformer. They were transported together from Royal SMIT in the Dutch city of Nijmegen by water to Kelheim’s port, where special transporters for road transport were already waiting. The last approx. 40 km to the substation at the Irsching power station were covered separately on two days: each transformer on a truck-trailer combination comprising 44 axles, with a length of over 90 m and a transport weight of 606 tons. It took approx. 5 hours to cover the distance.

Upon connection and commissioning, the two transformers from SGB-SMIT, which are positioned almost precisely in the center of Bavaria, have assumed a key function within the Bavarian power grid: they ensure reliable current transport in a North-South direction, relieve the existing transformer for the 220 kV circuits to Munich and contribute towards securing the energy supply of the metropolitan regions of Munich and Nuremberg. Thus, the SGB-SMIT Group makes a major contribution to grid expansion and modernization of the Bavarian branch of TenneT