Electromagnetic simulation tool helps to optimise generator

An advanced simulator from Vector Fields is aiding the detailed design of an ultra-efficient superconducting power generator. The electromagnetic simulator is helping the members of the Hydrogenie project to engineer a compact hydroelectric power generator offering up to 99 per cent efficiency, by exploiting developments in high-temperature superconducting (HTS) materials.

Led by Converteam, the Hydrogenie partners - EOn Wasserkraft, KEMA, Silesian University of Technology, Stirling Cryogenics and Refrigeration, Trithor and Vector Fields - are developing the technology for a 1.25MW generator that will be field tested at the Hirschaid power plant in Germany. The EUR3.44million project is being part-funded by the EU.

The hydroelectric generator being designed is a complex rotating machine with 28 poles. Electromagnetic simulation technology is being exploited to shorten the design cycle and characterise operating behaviour before construction begins. However, the accurate simulation of such a large dynamic machine in three dimensions would normally require an incredible amount of time and computing power.

Vector Fields has simplified this by producing a version of its Opera electromagnetic simulation tool that exploits the machine's rotational symmetry-and analyses just a segment of the design. Vector Fields is also helping the designers to generate the initial models that are being investigated during the early stages of the detailed design process.

Design optimisation

This approach is bringing the time required for the precision finite element analysis (FEA) simulation of the machine's dynamics down to a day or so on a standard desktop PC, giving Converteam the means to create virtual prototypes quickly and optimise the design. Vector Fields' Opera tool also supports 'multi physics' simulation, which can be used to explore how the generator design concept will perform under the range of mechanical load conditions.

Chris Riley, Hydrogenie Project Manager at Vector Fields, comments: "Vector Fields has pioneered the dynamic electromagnetic simulation of rotating electrical machinery, and this project has allowed us to develop the capability of the software to handle machines with a high number of poles. We are very excited to be part of such an ambitious project, which could play a key role in combating climate change."

Improved efficiency of hydroelectric power generation could lead to major benefits for society and the environment. Hydroelectric power is the largest source of renewable energy and, compared with fossil energy, it protects against harmful emissions including greenhouse gases and sulphur dioxide. In the EU alone, hydropower contributes about one-fifth of electricity production - averting the emission of some 76million tonnes of CO2 a year.

Generators based on HTS technology could increase global energy output by around 7 per cent. This would be equivalent to roughly another 40 conventional power stations - potentially a highly significant contribution to meeting Kyoto Protocol targets. The combination of HTS power generation and hydropower technologies has not been addressed before, despite its potential.

Hydrogenie's HTS hydro power generator has the following target specifications: 1.25MW power output, 214rpm, 99 per cent efficiency under partial load conditions, size and weight savings of 50-70 per cent over conventional technology, and an initial cost that is equivalent to a conventional machine.

The development roles of the Hydrogenie partners are:

• Converteam (formerly Alstom Power Conversion) - overall project management, co-ordinator and HTS generator design, build and test.
• EOn Wasserkraft - power station site selection, overall specification, installation and field testing of generator.
• Trithor - development and manufacture of high-temperature superconductive (HTS) rotor coils.
• Stirling Cryogenics and Refrigeration - cryocooler and cryogenic interfaces.
• KEMA - network integration and onsite installation concept and component testing.
• Silesian University of Technology - instrumentation, test procedures and quality concept for HTS coils.
• Vector Fields - electromagnetic design software.

More information on the project can be found at the Hydrogenie website.