Contact | Imprint | Source | FAQ | Deutsch | Search

Failure Rates of Components






Failure rates of system components for different locations

Data source: [WMEP 2006]



The average number of errors per year and plant for each of the major components are shown in the figure above. The individual plants are distinguished according to different location categories. It is striking that especially the wind turbines are affected near the coast and in the highlands of high failure rates. This can be for one certainly explained by the induced due to wind speed and turbulence heavier loads of facilities in these regions. Because of the great distances between the plants, particularly in the highlands, but also the maintenance service can be assumed as a crucial factor. Most of the reported incidents is due to defective or loose components as well as malfunction of the system rules. In less than a quarter of all cases, the disturbances were caused by external influences such as storm, lightning, ice accumulation and power failure. While the cause of power failure is independent of the season and location, the other external conditions, however, show in addition to a seasonal also a significant spatial dependence. Especially in the higher altitudes of the mountains, for the already many times more icing cases reported, the ice-promoting weather conditions can still occur until late in the spring. For upland sites a significantly higher risk for the disorder causes "Storm" and "Power Failure" available.





Failure rates of system components for different system concepts

Data source: [WMEP 2006]



In addition to the location of the plant, the technical equipment of the wind turbines, of course, plays a crucial role in the reliability of the system. In the figure above, the average annual failure rates for the different technical concepts are presented. In most cases, a trend observed toward higher failure rates with increasing complexity of the technical concept. In almost all components of the wind turbines of the variable speed concept have the highest failure rates. With the increasing complexity of the systems thus increases while the efficiency of the plants, but not necessarily the reliability. The only downward trend, the figure below shows, can be observed for the drive train. Due to lower pressures by various regulatory options for stress reduction and support of electronic components, such as the mechanical brake is still the most stress in a stall controlled turbine, which manifests itself in a high failure rate. With the introduction of pitch control, and later by additional protective measures the error rate of this component has been continuously reduced. On the other hand, especially the electrical and electronic sector of the wind power plant has gone through significant deterioration in the course of technical evolution in terms of error rate.

The two figures above are taken from the WMEP claims database. This database was established between 1989 and 2006 with the help of the "Scientific Measurement and Evaluation Programme" (WMEP) as part of the "250 MW Wind" programme. During this period, 193,000 monthly energy supply reports and 64,000 reports on maintenance & repair measures for approx. 1,500 wind turbines were collected and analysed. The aim of WMEP was to collect statistically proven empirical values on the practical use of wind energy on a scale relevant to the energy industry and to evaluate them according to uniform criteria. The results of the project still represent one of the few reliable sources of information regarding the reliability of the turbines and their components.