RESEARCH AND DEVELOPMENT
In the field of hydraulic R&D, both contract-oriented developments and basic innovations were carried out successfully.
One focus during the reporting period was the integration of the research and development know-how of the assets acquired from GE Hydro and ANDRITZ HYDRO in the areas of hydraulic and mechanical development as well as dynamic simulation. Former GE Hydro has extensive experience in the area of large Francis turbines, and ANDRITZ HYDRO contributes the results of value analyses for this product.
Hydraulic developments focused on low-pressure Francis turbines. Using Computational Fluid Dynamics (CFD) methods and model tests, a new hydraulic design was developed for the plant in Bemposta (head: 63.3 m, output: 193 MW), Portugal.
In the area of high-pressure Francis turbines, a new hydraulic design was developed for the Karcham Wangtoo project in India (head: 300 m, output: 255 MW). This new design enables complete coating of the blade channels as protection against sand abrasion. Due to the high sand content of the water, uncoated stainless steel runners would be abraded very rapidly. The new coating significantly extends the runner’s useful life.
For pump turbines, development work was successfully continued in the area of high-pressure pumps. Developments included a new runner profile for the rehabilitation of a 300 MW pump turbine in Europe. Flow simulation and subsequent model tests were used to optimize the customized characteristics of the runner.
The new Kaplan turbine hydraulics developed for the Box Canyon, USA rehabilitation project have resulted in a capacity increase of 30%. The very high efficiencies and excellent cavitation behavior were proved in acceptance tests.
Based on the long-term, intensive research activity in the cfd area of the distributor ring for Pelton turbines and Pelton jet, CFD has become the standard for analysis and optimization of the turbine characteristics. Thus, in the hydropower station project Lotru, Romania, CFD and model tests were successfully combined. The current focus of research work is on the Pelton jet.
A focus of the generator development during the year under review was the optimization of vertical generators. Generators with a comparatively low capacity are now beginning to be the subject of a parameterized design system, which would allow carrying out the necessary optimizations.
Also with the goal of optimization, a concept for flexible coupling of the plate stacking to the rotor was developed for a specific generator type. This design solution will result in significant cost savings.
Based on a comprehensive value analysis for turbo generators, a further prototype of the new series was successfully tested in 2008. Extensive real-time recordings of approximately 1,100 measuring points allowed precise calibration of the finite element method and the CFD models applied. The findings of these tests have been practically applied to a further prototype of this new turbo generator series.
Parameterized CFD models were also developed for radial fans, as they had been for axial fans, in the aim to permit comparatively rapid and reliable calculation of the characteristic curves. In-depth CFD analyses for fresh oil feed to bearings have led to efficiency increases. A design for spring-supported bearings for large generators has enlarged the spectrum of potential designs.
The quality of bar manufacturing has been considerably improved with regard to process-related variances of the dielectric features of insulation, resulting in more uniform and better insulation quality.
In the development of bulb generators, the prototype of the new thermomechanically decoupled stator concept installed in Freudenau power station, Austria was extensively tested. The technical requirements of the customer, Verbund-Austrian Hydro Power (AHP), were fully met, resulting in a further order including the new stator concept for the rehabilitation of Melk power station on the Danube.
An essential focus of the research and development work related to automation for hydropower stations. Following optimizations to 250 SCALA (the leading SCADA system for control rooms and operator stations including the smallest displays), an extensive development project was started in 2008 in the high-end range with the goal of achieving an all-around system and safety solution for groups and cascades of power stations. In addition, a hydro-energetic overall optimization of hydropower cascades is performed on the basis of mathematical models. These automation developments have become necessary because of the rising number of widely spread hydropower parks incorporating a large number of single stations. This is a consequence of the liberalization of the energy market and of mergers of energy generation companies.
The research and development work for large pumps focused on the further hydraulic development of existing hydraulic designs for impellers and distributors. This has led to significant improvements in efficiency and cavitation behavior. In addition, a development project for a concrete spiral pump with high specific speed for large flow rates was started and successfully completed. In the area of centrifugal pumps, the focus was on efficiency improvements of the existing product series with the goal of further reducing the energy costs for end users.