We have investigated the reliability of more than 6000 modern onshore wind turbines and their subassemblies in Germany over 11 years and particularly changes in reliability of generators, gearboxes and converters in a subse Schleswig Holstein, Germany. We first start by considering the average failure rate of turbine populations and th failure rates of wind turbine subassemblies. This analysis yields some surprising results about which subassembl unreliable. Then we proceed to consider the failure intensity function variation with time for wind turbines in on populations, using the Power Law Process, of three subassemblies; generator, gearbox and converter. This analy turbine gearboxes seem to be achieving reliabilities similar to gearboxes outside the wind industry. However, win generators and converters are both achieving reliabilities considerably below that of other industries but the reli subassemblies improves with time. The paper also considers different wind turbine concepts. Then we conclude offshore wind turbines should be subject to more rigorous reliability improvement measures, such as more thor testing, to eliminate early failures. The early focus should be on converters and generators. Reliability of wind turbine subassemblies References (18) Cited By (214) Supplementary material (0) Keywords Related C Article

Modern wind turbines are complex aerodynamic, mechanical and electrical machines incorporating sophisticated control systems. Wind turbines have been erected in increasing numbers in Europe, the USA and elsewhere. In Europe, Germany and Denmark have played a particularly prominent part in developing the technology, and both countries have installed large numbers of turbines. This article is concerned with understanding the historic reliability of modern wind turbines. The prime objective of the work is to extract information from existing data so that the reliability of large wind turbines can be predicted, particularly when installed offshore in the future. The article uses data collected from the Windstats survey to analyse the reliability of wind turbine components from historic German and Danish data. Windstats data have characteristics common to practical reliability surveys; for example, the number of failures is collected for each interval but the number of turbines varies in each interval. In this article, the authors use reliability analysis methods which are not only applicable to wind turbines but relate to any repairable system. Particular care is taken to compare results from the two populations to consider the validity of the data. The main purpose of the article is to discuss the practical methods of predicting large‐wind‐turbine reliability using grouped survey data from Windstats and to show how turbine design, turbine configuration, time, weather and possibly maintenance can affect the extracted results. Copyright © 2006 John Wiley &Sons, Ltd.

Wind turbines have been erected in increasing numbers in Europe, the USA and elsewhere. In Europe Denmark has played a particularly prominent part in developing the technology and has installed a large numbers of turbines. The paper is concerned with the influence of the weather on the reliability of modern wind turbines and in particular the effect of wind speed. The prime objective of the work is to extract information from existing reliability data to draw conclusions about how the wind speed affects turbine reliability and which subassemblies in the turbine it affects the most. The purpose is to make information available to turbine manufacturers and operators so that the reliability of new wind turbine designs can be improved, particularly if they are to be installed offshore, where the weather is more inclement. Data are collected from Windstats for historic, maintained, Danish wind turbines and on-line data collected for the Danish weather. These data are used to analyse the reliability of wind turbines and their subassemblies in varying weather conditions from 1994–2004. The paper describes practical methods of extracting information from wind-turbine reliability data and shows how turbine design, turbine configuration, time and the weather can affect the extracted results.

Electrical Machine/Converter combinations are used in a variety of applications, from powers of Watts to MegaWatts. Some applications, such as propulsion and generation, have high reliability & availability requirements. Modern large wind turbines incorporate variable pitch blades and a variable speed Generator, which feeds the Grid through a Converter and have a need for high reliability & availability. There are a number of configurations of generator and converter intended to provide optimum performance for present and future wind power. This paper describes an investigation into the reliabilities of Generators and Converters in such configurations and is based on failure data collected in Germany and Denmark. The paper draws conclusions about which configurations have the higher reliability and identifies the subassemblies of the turbines which require attention for the future design of high reliability wind turbines.Recommendations are made about how designers and operators of wind turbines can increase their reliability by the choice of Concept and the operating regime

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