Germany - Siemens Energy presents energy-efficient power supply solutions in Hanover

At this year's Hanover Fair Siemens Energy presented smart, eco-friendly solutions for power generation, transmission and distribution. The highlights included a new 2.3-MW gearless wind turbines for low wind speeds, solutions for the connection of offshore wind farm plants to the grid using high-voltage direct-current transmission technology (HVDC) as well as a charging point, which can charge electric vehicles with a normal lithium ion batteries capacity within an hour. They also featured new gas-insulated switchgear and a prototype of a 72.5-kV circuit-breaker with a vacuum interrupter as the switching element.

For low to moderate wind speeds Siemens Energy has developed a new gearless wind power generator, which the company presented in Hanover. The core feature of the SWT-2.3-113 wind energy generator is an innovative drive concept with a compact permanent magnet generator. This type of generator is characterized by its simple, robust design, requiring no power for excitation and control systems and don't need sliprings. This results in high efficiency even at low loads. With a capacity of 2.3 megawatts (MW) and a rotor diameter of 113 meters the new wind turbine is designed to maximize power production at sites with low to moderate wind speeds. It is fitted with the new Siemens B55 Quantum rotor blades. This new blade design boosts efficiency and optimizes performance. A prototype of the new Siemens wind turbine was installed in the Netherlands in early March.

The Charge CP700A charging point can charge electric vehicles with a normal battery capacity within an hour. The charging power has been doubled to 22 kilowatts (kW) in the new series, which in turn cuts charging time in half. In the fastest operating mode the vehicle is supplied with three-phase AC voltage at a current of 32 amperes (A) and is therefore charged at a power level of 22 kW. Charging is, however also possible both in single- and three-phase mode. The charging point communicates with the vehicle over the charging cable to determine whether the electric car supports charging at maximum current (32 A) or only at a reduced current level (20 A). A standardized IEC 62196-2 Type 2 connector is used for this. The charging point can also be linked to a control center over Ethernet or an integrable GSM/GPRS modem, meaning that it is ready for remote monitoring and maintenance. The charging behavior of the charging point can be remote-controlled to support implementation in a smart grid.

Using the example of the grid connection for the DanTysk offshore wind farm, which will be part of the SylWin wind farm cluster in the North Sea, Siemens showed in Hanover how efficiently such wind farms can be connected to the grid with the aid of offshore substation platforms. DanTysk is being built west of the island of Sylt and will feature 80 Siemens wind turbines with a combined capacity of 288 MW. A Siemens HVDC Plus system will be installed on an offshore substation platform together with the transformers and gas-insulated high-voltage switchgear for energy-efficient transmission of the power generated by the wind farms of the cluster to the mainland. Siemens supplies this Wind Power Offshore Switchgear (WIPOS) technology on a floating, self-lifting platform, which is pulled to its site on the open sea using ocean-going tugs. The alternating current produced by the wind turbines will be converted to direct current on the platform, which will later be located directly adjacent to the wind farm in the North Sea. The direct current will be brought to a transmission voltage of 320 kilovolts (kV). The power will then be transmitted with low losses to the grid feed-in point on the coast, where the electricity will be converted back from direct to alternating current in a converter substation.

Siemens also exhibited a new generation of NXAIR air-insulated switchgear. Experts revised the design of the existing product line with the aim of developing a platform concept for deployment worldwide and bringing it to the marketplace. The result is a factory-assembled, type-tested switchgear unit to IEC 62271-200, with IAC A FLR internal arc classification, LSC 2B category operating availability and cladding class PM (metal-clad). The NXAIR switchgear unit covers the rating range ≤ 17,5 kV, ≤ 40 kA, ≤ 4000 A. By virtue of its platform concept the switchgear can be produced both at Siemens manufacturing plants in Africa and Asia and at plants in the Americas and Europe and are therefore available worldwide.

The newly developed high-voltage switchgear presented by Siemens in Hanover included a new variant from the 8DQ1 product line of gas-insulated switchgear. This switchgear unit is of particularly compact design with a rated voltage of 420 kV, a rated short-circuit current of up to 63 kA and a rated current of up to 4000 A. The switchgear operates with a single-break circuit-breaker with a break time of less than two periods. By virtue of its compact design the newly developed switchgear is suitable for installment at locations where the space available would not be sufficient for a customary gas-insulated high-voltage unit with these ratings – a particular advantage in extensions to urban power networks.

With a prototype version of a vacuum circuit-breaker and a design study on a 145-kV vacuum interrupter Siemens demonstrated in Hanover that vacuum circuit-breaker technology need not stop at 52 kV but is also technically feasible for deployment in high-voltage networks. With 40 years of experience in the production of medium-voltage vacuum interrupters and more than three million units supplied Siemens is now launching the field-proven technology for the high-voltage level. The vacuum circuit-breaker series will fulfill the same quality standards as the Siemens gas-insulated high-voltage circuit-breakers and will also be of modular design. The prototype of the 72.5-kV vacuum circuit-breaker was tested in a complete series of type tests in accordance with the current version of IEC 62271-100. Some of the circuit-breakers of this prototype series have already been installed for tests and studies in European grids. They will be launched after successfully completion of the practical studies.

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