Reliability analysis for wind turbines

Abstract

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.

A brief status on condition monitoring and fault diagnosis in wind energy conversion systems

“…This is clearly illustrated by Another study, concerning Danish and German wind power plants [10], shows the same tendency. Indeed, principal contributors to the higher German failure rate are the electrical control or system subassemblies (grid or electrical system, yaw system and mechanical or pitch control system) rather than mechanical subassemblies such as the gearbox.…”

“…Real wind turbine failure data quantitative analyses have shown important features of failure rate values and trends [8][9][10][11]. For illustration, Fig.…”

Reliability analysis for wind turbines with incomplete failure data collected from after the date of initial installation

“…Danish data shows a decreasing number of installed turbines, while German wind turbines increase rapidly [9] [10] . Since the population changes, it's necessary to eliminate the population difference by normalizing the wind turbine reliabilities.…”

“…concluded that fewer authors have worked on reliability evaluation of wind turbine systems [8] . Valuable information for wind turbine reliability analysis can be derived from failure data by statistical analysis [9] [10] . Climate change can also be taken into account using statistical data [11] .…”

Wind turbine SCADA alarm pattern recognition

“…Current studies of wind turbines focus on improving reliability [4,9,10] because good wind turbine reliability, together with predictable turbine maintenance schedule, will result in a reduced cost of energy, which will determine the success of a wind farm project. This is even more important for offshore wind farms due to their high initial capital cost and limited accessibility, causing higher operational and maintenance (O&M) cost [11,14] and prolonged capital payback.…”