Power exchange to become more economical

May 13, 2013
Power exchange to become more economical
Power electronic modules of Siemens multilevel direct converters, being used in Häggvik in the greater Stockholm area in Sweden: The Sitras SFC plus systems use state-of-the-art multilevel power converter technology, which makes it possible for them to convert energy highly efficiently and with almost no system perturbations. In addition, they are quieter than conventional systems and have a smaller footprint. To strengthen the traction power supply networks by establishing additional links to the public power supply grid, Siemens will supply more converters of this type to Sweden and to Switzerland.

Siemens is facilitating the efficient flow of energy between the power network of an electric railway system and the public power grid. The company is delivering 11 gateway power converters to Sweden, Austria and Switzerland. In these countries, and many others, the rail system operates its own power plants and a private electrical grid that is connected to the public grid at certain points. As the amount of renewable energy increases, these connection points are becoming more important. For example, the rail system in Sweden has plans for eight new converters that will provide access to hydroelectric power from the public grid beginning in mid 2015. In Austria, a new converter will allow the rail system to feed excess electricity generated by its own hydroelectric plants to the public power grid more efficiently starting in 2014. The new converter will also connect the planned Tauernmoos hydroelectric plant with the railway system grid. Altogether, including two converters for Switzerland, these contracts are worth a total of €68 million.

Power converters change the frequency and voltage of electricity in one system so that it can be fed into another system. They are necessary because in the countries already mentioned, as well as in Germany, the railway system grid uses a frequency of 16.7 Hz, whereas the public grid operates at a frequency of 50 Hz.

The direct converters, contracted from Siemens, are from the Sitras SFC plus series. These use a modular construction of multiple power transistor components (IGBT) and capacitors connected in series to reach the desired voltage incrementally. This modern, multilevel technology loses less power during conversion compared to the previous standard solution. In addition, these units are clean. In other words they generate harmonic-free power and voltage conversions, so additional filters are not required. Multilevel installations are quieter and more compact then traditional converters and are therefore more suitable for urban areas. In Germany, Sitras SFC converters are already connecting the railway system grid with the Franken 1 power plant in Nuremberg-Gebersdorf. Nationwide, four more units will be installed in the German railway system grid in the next two years.

Siemens is also introducing this efficient multilevel conversion technology to high-voltage direct-current transmission applications. For example, it can be used to connect wind farms to the public . Technologies for the efficient transmission and transformation of electricity are part Siemens' Environmental Portfolio, which earned the company sales of around €33 billion during the last fiscal year.

Explore further: Aged national power grid leaves US vulnerable to outages from spring storms

Related Stories

Power storage buffers fluctuating solar power

May 11, 2012

Siemens has developed an energy-storage system that can act as a buffer in electrical power grids. The aim is to provide a buffer against short-term fluctuations in output from renewable energy sources. Such fluctuations ...

Smart software for self-regulating smart grid

May 24, 2011

Siemens and the utility company Allgauer Uberlandwerk (AUW) in the city of Kempten, Germany, are testing the smart grids of the future. The tests focus on optimized power distribution and the use of a self-organizing energy ...

Grid stability thanks to precise forecasts

June 11, 2012

A self-learning software system from Siemens can stabilize power grids. The program, which is based on neural networks, can forecast the electrical output of renewable energy sources over a 72-hour period with more than 90 ...

A world record in direct current transmission

May 3, 2011

Siemens is building power converter stations for a high-voltage direct current (HVDC) transmission system with a record capacity of 2 x 1,000 megawatts. Beginning in 2013 the new HVDC PLUS technology will transmit 2,000 megawatts ...

Recommended for you

A not-quite-random walk demystifies the algorithm

December 15, 2017

The algorithm is having a cultural moment. Originally a math and computer science term, algorithms are now used to account for everything from military drone strikes and financial market forecasts to Google search results.

US faces moment of truth on 'net neutrality'

December 14, 2017

The acrimonious battle over "net neutrality" in America comes to a head Thursday with a US agency set to vote to roll back rules enacted two years earlier aimed at preventing a "two-speed" internet.

FCC votes along party lines to end 'net neutrality' (Update)

December 14, 2017

The Federal Communications Commission repealed the Obama-era "net neutrality" rules Thursday, giving internet service providers like Verizon, Comcast and AT&T a free hand to slow or block websites and apps as they see fit ...

The wet road to fast and stable batteries

December 14, 2017

An international team of scientists—including several researchers from the U.S. Department of Energy's (DOE) Argonne National Laboratory—has discovered an anode battery material with superfast charging and stable operation ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.