Theodor-Heuss-Allee 20, 28215 Bremen


Since 2014




IEC 60870-5-103

wesernetz Bremen GmbH and wesernetz Bremerhaven GmbH are the grid operators for electricity, natural gas and domestic water and heat in the state of Bremen and for the natural gas grid in Stuhr, Weyhe and Thedinghausen. Among the core duties of the company are the construction, management, maintenance, servicing and expansion of the grids.


The power grid in Bremen comprises more than 9,400 km of power lines, around 40 transformer stations and distribution stations, a 110 kV transmission grid and a 10 kV medium voltage grid. “A respected manufacturer has a new technology on the market. So we are keen to run a pilot project to test out that technology. The value for money of the functionality offered promises to be extremely attractive.” That was the statement made by Sören Sturm, service power team leader at wesernetz Bremen GmbH, after the presentation of our SG-50 combination protection unit in his specialist department. And so a test unit was first rigorously tested at the wesernetz Bremen laboratory and even linked up live to the control system in the process. Based on the very positive test results, a deployment opportunity was immediately found for the units in the 10 kV grid. Due to grid modifi cations, three distance relay installations were required at the Huchting transformer station.

When installing the units in the switchgear panels, another fundamental advantage became evident: the size of the protective device is ideal for conversions of this type. Whether installed in the door or – as in this instance – with the support brackets on the rear panel, the modest dimensions of the housing are easily accommodated.

A new feature is the display of the panel and its switch conditions and measured data on a colour screen. Not only the currents, voltages, power data and cos phi can be read off but also the continuously measured R and X levels of the cable. “So it is a fully featured protection and control unit!” confirms Sören Sturm.

Project planning was in the hands of Stefan Diers and his team using the intuitively usable Digicom configuration software. They too were full of praise, especially regarding the modularity of the software. Even in an installed state extra protective functions can be added to the systems. With the Digicom software tools, the system layout could be designed just as easily as the system automation. “The tools are easy to understand, user-friendly and self-explanatory – simply delightful!” enthuses Stefan Diers.
Colleagues Sören Sturm and Stefan Diers deliver their verdict on the pilot project thus:
The SG-50 Kombisave is an easily confi gurable and economical protective device that can be used in the Bremen medium-voltage grid and fully satisfi es the existing requirements.