Measures for preventing wear of machinery in wind turbines

In 2030, half of the 146,000 megawatts of wind power installed in Europe will be more than 20 years old, thus exceeding the useful life of two decades that until not so long ago was attributed to these installations. Of all the ones to be found in the continent, the Danish, German and Spanish ones are the oldest, so they will be the first to undergo reforms aimed at achieving the new expected milestone: preventing the wear of machinery in wind turbines, increasing their useful life by ten years and maximising their return.

In Spain, the autonomous communities that have most farms from before 2001 are Galicia and the Canary Islands, with 36 installations each, Navarra, which has 22, then Castilla y León with its 17 and Aragon, which has 15. In view of the lack of incentives in Spain for repowering, that is to say the replacement of old equipment by other more powerful, units, extending the life of the machines is a natural solution for the owners of the wind farms. Logically this aspiration must come about through sound processes that provide a return on investment.

In this context, an analysis of extension of life together with the correct maintenance of the critical elements of the machinery and the replacement of components in wind turbines have become the most viable solutions for reaching the goal.

Supervision of the wind farm maintenance in the guarantee period

After the installation and start up of a wind farm a guarantee period begins during which the maintenance of the different components is normally managed by the manufacturer of the machinery, though this depends on the project.

As in many other sectors, wind power is noted for high competition within a small market, in which a close offer can tip the balance in favour of a contractor. This scenario means that manufacturers seek ways of reducing their costs and can affect the depth or the detail with which it performs the maintenance work to which it is obliged. To avoid disagreeable surprises once the guarantee period has expired it is recommendable for the maintenance work to be supervised from the management of the equipment of the.

Activate a strategy of predictive maintenance

Before the expiry of the guarantee period in which the supplier of machinery assumes the maintenance of the wind farm, it is necessary for the final user to know the condition of the wind turbines in order to attribute liability in the event of possible problems. For this, there is the option of carrying out technical audits or individual inspections of each machine allowing the final managers to have a snapshot of the condition of the wind turbines.

At this point, the approaching expiry of the guarantee, must be taken as to how to continue the maintenance of the installations: to follow the way that has been started and extend the existing contract, or adopt a decided posture and choose to implement a strategy of predictive maintenance for the medium and long term as a way of prolonging the useful life of the wind farm.

Investing strategically to prevent risk failures

The useful life of a wind farm is conditioned by many factors of different kinds, structural, mechanical and electrical, that can interfere in the performance of the wind turbines and lad to failures of various kinds. The monitoring of the different elements that make up the wind turbines would provide a complete X-ray of the condition of the machine, but it would also require a large investment.

In view of these circumstances, in which combining various condition monitoring technologies is not financially viable, it is necessary to evaluate what are the most probable kinds of failure and with the greatest repercussion for directing investment available for in maintenance towards the components that present the greatest risks.

In this regard, one of the elements that weighs most in the cost of mechanical maintenance of a wind turbine is the multiplier, a critical item whose possible failure can lead to long stoppages and high costs for repair. In this field, the technology of oil sensors, sensors that allow real time measurement of the condition of the lubricating oil, makes it possible to detect operational risks that are hard to diagnose, because they are often hidden.

Retrofitting to prolong the life of the turbines

In recent years, retrofitting practices have been gaining ground as a way of prolonging the useful life of the wind turbines. Retrofitting, or the replacement of components and implementation of new technologies in old systems, requires a lower investment than the replacement of the machinery and positively affects the life expectancy and efficiency.

These processes of renovation of components and technologies have led to the development of companies that analyse the operating conditions of the wind turbines and design the modifications that each machine would need to extend its operating time and obtain more energy.

Industry 4.0. Data for improving operation

The fourth industrial revolution has brought with it an interesting breakthrough in the capacities for communication, storage and analysis of information that can help to optimise the operation of critical machinery and notably minimise its possibilities of failure.

The principal added value of the implementation of measurement and sensor systems associated with Industry 4.0 is the interconnectivity of the machines and the centralisation of data. The information and communication technologies the make it possible to install smart sensors and data capture systems in the machines, so that it is possible to obtain information about the state and the operation of the equipment in real time. The interpretation of these data is a great help in taking decisions that will improve the operation of the machines, both individually and all together, and in optimising the processes for the generation of energy.

Moreover, the sensor systems give early visibility to a great variety of problems, many of them hard to detect in other ways, and they make it possible to anticipate possible breakdowns and to take steps to minimise their impact.

Starting from the data capture, it is possible to establish operating models that make it possible to optimise the design of the wind turbines, to plan stoppages for the maintenance and even to do work on the equipment in the most appropriate conditions at any time, which has a positive effect on its useful life.