Siemens stabilizes SSB’s traction power grid with mobile reactive-power compensation – Jul 08, 2013– Nuremberg, Germany  (Techreleased) – In order to ensure their traction power supply in the event of a partial system failure or unforeseeable network operating conditions, Swiss Federal Railways (SBB) has commissioned Siemens’ Smart Grid Division to design and supply mobile 15-MVAr reactive-power compensation systems that can be deployed anywhere within the SBB rail network on demand. The order was placed following a public invitation to bid. The project will result in the first mobile reactive-power compensation systems for a traction power supply in the world. Installed, for example, on rail cars, these systems can be quickly moved anywhere within the SBB traction power-supply network and deployed directly where needed. They will provide reactive-power compensation, improve voltage quality, and increase the stability of the network.

Siemens' Smart Grid Division
Siemens’ Smart Grid Division

The order volume is 9.3 million Swiss francs. The first two units, which will be located on the south side of the Simplon Tunnel, will be commissioned at the end of 2015. A third unit is earmarked for the network area Neuhausen am Rheinfall, Switzerland. Siemens and SBB also agreed on an option for delivery of an additional four mobile reactive-power compensators worth about ten million Swiss francs.

“One of our strengths lies in finding business solutions jointly with our customers. Our contract with SBB to deliver mobile reactive-power compensation containers is a perfect example,” said Mirko Düsel, CEO of the Rail Electrification Business Unit in the Siemens Smart Grid Division. “The mobile containers will give us the flexibility to provide additional reactive-power compensation and stabilize the network wherever that’s needed,” commented Markus Siegenthaler, Project Manager at the Energy, Telecom, and Electrical Systems business sector of SBB Infrastructure.

The first mobile reactive-power compensation containers will be deployed on the south side of the Simplon Tunnel. This 20-kilometer-long tunnel links Switzerland and Italy and is an international transit route for freight and passenger traffic. The compensators, which are installed in 40-foot high-cube containers, will stabilize the traction voltage in the network and improve power quality. The mobile containers are connected to the overhead contact line by cable via a plug-in connection. The containers can be connected to the network control system via a telecontrol interface. Auxiliary services can be powered with either 15 kV/16.7 Hz via the traction power supply or with 400 V/50 Hz via the national grid. Each container contains gas-insulated medium-voltage switchgear, power converter technology, a cooling unit as well as protection and control technology.

The Sitras SVC Plus (static var compensator) reactive-power compensation systems operate on the basis of voltage-sourced converter technology. Similar to the Siemens frequency converter Sitras SFC Plus, the core element of the reactive-power compensators is the modular multilevel direct converter technology. As a result, the voltage waveform generated by the system is virtually sinusoidal. The power converter consists of a large number of series-connected power transistor modules (IGBT) and capacitors – hence the name multilevel voltage-sourced converter. These series-connected modules act like a controllable voltage source that builds up the sine-wave voltage. This enables the low-frequency harmonic filters needed in existing solutions to be eliminated, which considerably reduces the space required for the entire system and allows it to be installed in containers.

Energy-efficient, eco-friendly solutions for setting up intelligent power supply networks (Smart Grids) are is part of Siemens’ Environmental Portfolio. In fiscal 2012, revenue from the Portfolio totaled about 33 billion euros, making Siemens one of the world’s largest suppliers of eco-friendly technologies. In the same period, our products and solutions enabled customers to reduce their carbon dioxide (CO2) emissions by more than 330 million tons, an amount equal to the total annual CO2 emissions of Berlin, Delhi, Hong Kong, Istanbul, London, New York, Singapore and Tokyo.