Maximum performance for wind turbines

A lack of network capacity, major voltage fluctuations, continuously changing wind conditions, coasting and the intermittent driving of components: Wind turbines are highly susceptible to interference. A high level of gear wear associated with frequent gearbox changes is the result. 1 -2 gearbox replacements per year in wind turbines are not uncommon. The negative consequences are machine downtime, a lower energy balance, high maintenance costs and prolonged energetic duration. Preventive measures against premature gear wear can therefore certainly lead to major costs savings.

The main causes of gearbox failure in wind turbines are damage resulting from friction, such as grey staining, roughness and pitting (link to relevant blog article). Once it is possible to reduce the frictional forces and the associated wear and tear, the number of necessary gear changes is reduced significantly at the same time. An extremely effective approach against wear and tear is so-called surface passivation using enrichment with silicon atoms that form a smooth and wear-proof metal-ceramic layer during the friction process. The surfaces are now much smoother and friction and wear fall drastically, the gearbox of the wind turbine runs more efficiently and with less vibration. At first glance, a rather complicated sounding protective measure, at a closer look, however, quite simple with the use of an innovative oil additive. The oil additive DuraGear^® W100 specially developed for wind turbines (link to landing page) is added to the lubricant of the wind power gearbox during operation and uses this to transport active agents to damaged points - without affecting the lubricant itself in any way.

The company Windkraft Simonsfeld, one of the largest Austrian wind power producers, made a conscious decision to boost the performance of its wind power plant and the maintenance of its gearboxes using DuraGear^® W100 and contacted the Lahnau manufacturer REWITEC^®. The priority objectives of the application were to improve the gearbox condition and prolong the service life. Likewise, the gear flank load capacity was to be optimised and the current state of damage frozen. At an on-site meeting at the wind turbine Vestas V80 in Steinberg Prinzendorf, the wind turbine gearbox was inspected by the engineers from the company REWITEC^® before the DuraGear^® W100 was used. What was observed was running marks on the gear flanks and so-called run-throughs, as well as rust-like discoloration in the base area. The surfaces were rough, an electrical resistance measurement showed a value of up to 20 ohms. For a before / after comparison, highly accurate surface impressions (resolution 0.1 micron accuracy) were taken from a previously selected gear flank and then examined under a microscope. After that, the Hansen gearbox of the wind turbine was treated with the tribological coating concentrate DuraGear^® W100. The results after seven months running with DuraGear^® W100 were remarkable. A detailed examination of the gearbox showed a slight decrease in the rust-like deposits and a reduction in the running marks on the surface, leaving the surfaces feeling significantly smoother. The electrical resistance had increased to up to 200 Ohm. Evaluations by laser scanning microscope (type "Keyence VK8700") demonstrated an improvement of roughness values of Rz 8.899 to Rz 7.036μm and Ra 0.595 to 0.411μm. The bearing surface had increased from 46.402% to 58.702%. CMS analysis showed that the trend in the vibrations measured had significantly reduced after application.

Since the middle of 2010, the company Marxen Bauträger has been using DuraGear^® W100 and has been treating the gearboxes of all 25 wind turbines regularly with the innovative oil additive. Since then, there have been no more gearbox failures. Before the application, there had been an annual average of 1-2 gearbox changes, now the savings over 5 years and 25 wind turbines is € 562,500.

Turbulent regions with high wind speeds generally provide the best wind harvest. However, frequently changing wind conditions and often very unstable network structures tend to have an adverse effect on the maintenance of gearboxes. The intermittent driving of mechanical components means that tribological related wear is significantly higher than in regions with more stable wind conditions. Therefore, many wind farm operators deliberately forego a higher wind harvest in favour of a better network connection and more constant wind conditions. Surface passivation with DuraGear^® W100 decreases the mechanical "loading" acting on the gearbox even in unfavourable conditions, so that operators of wind turbines can operate wind turbines in the future even in windy regions and without increased repair and failure risk.