The gearbox is an important component of a wind turbine (WT). Once the gearbox is damaged, problems such as long-term maintenance and high maintenance costs will occur. Therefore, it is necessary to carry out on-line condition monitoring (CM) of WTs. Because a large amount of data is accumulated by the supervisory control and data acquisition (SCADA) system, CMs based on data-driven methods have been widely investigated. In this paper, a CM method that is based on the KNN regression method and bagging ensemble strategy is proposed. The proposed method is validated by SCADA data collected from a field WT. The results show that the ensemble model can achieve the desired estimation accuracy and improve the operation efficiency by approximately 30%.
INDEX TERMSWind turbine gearbox, data-driven method, condition monitoring, KNN, bagging.
I. INTRODUCTIONTo cope with global climate change, China has announced that it will achieve peak carbon dioxide emissions by 2030 and carbon neutrality by 2060 [1]. Therefore, clean energy power generation technology has broad development potential. As a kind of clean energy, wind energy has been widely utilized worldwide. According to the Global Wind Energy Council (GWEC)ś report [2], although the global newly installed capacity reached 93 GW in 2020, a large number of wind turbines (WTs) still need to be installed. With an increase in the number of wind turbines in service and the extension of operation times, the possibility of component failure also increases. According to the statistical data [3], due to the harsh operating environment and other conditions, the gearbox is the component of WTs with a high incidence of faults. Once the gearbox is damaged, problems such as high maintenance costs, complex maintenance processes, and long maintenance times due to structural constraints will ensue [4]. Therefore, it is necessary to carry out online condition monitoring (CM) of gearboxes.The CM of gearboxes is divided into vibration signal analysis [5], oil quality analysis [6] and supervisory control and data acquisition (SCADA) system data analysis [7] The associate editor coordinating the review of this manuscript and approving it for publication was Dipankar Deb . according to different signal sources. However, vibration 33 signal analysis requires the installation of professional 34 sensors to collect high-frequency vibration data, resulting 35 in additional expenses. Oil quality analysis is an invasive 36 method that cannot realize online monitoring. Presently, 37 almost all wind turbines are equipped with the SCADA 38 system [8], which can collect a large amount of operational 39 and record fault data. Therefore, WTCM based on SCADA 40 data has been widely employed by scholars. 41 235 a small constant, so the complexity of the conventional KNN 236 algorithm and bagging integrated KNN algorithm has the 237 same order of magnitude. 238 C. THRESHOLD SETTING METHOD 239 The output of condition monitoring is often a continuous 240 value, but we cannot judge whether the gearbox is faulty...