# Technological Advances on Fault Diagnosis in Wind Turbines: A Patent Analysis
## 3 Results and Discussion
These organizations make it possible to apply for several international applications through a single application, such as the WIPO Patent Cooperation Treaty (PCT). Most technology manufacturers are looking to secure their inventions through international applications via EPO and WIPO with the aim of reducing costs and simplifying the individual filing process in each country while protecting their technology in several countries. In regard to the technological areas of the prospective inventions (Figure 4), 24 technology classifications were discovered. According to the DWPI database, the number of technologies points to recent innovations and can provide an important overview of the \"state of the market\" and how it is segmented. The number of technology area assignments to patent applications can report a diversified portfolio or a specific technical focus. As it can be noticed, the three leading companies in development in these technological areas are Vestas Wind, State Grid Corp, and Gen Electric, and they count for 41% of all records in the resulting set. In regard to the technological area (a), pink refers to \"wind turbine, rotor blade\". Here, Gen Electric has 47% of their patent applications classified in this area, while Vestas Wind has 38% and State Grid Corp has 28%. From this result, we can observe that practically all the applicants have patents that fit in this technological area. The technological area (b) in blue refers to \"additively, three-dimensional printing, additive, composite, build, thermoplastic\", and (c) purple refers to \"testing, leakage, abnormality, monitoring, sensor, detecting, inspection\". The identified patent applications in these technological areas most often seek improvements in wind turbines, especially in individual turbine parts, such as motors, blades, and gearboxes. In addition, many of the patents describe a new device or even a novel method for fault diagnosis based on non-destructive testing. [PERSON] et al., 2022 [90] described a utility model using an infrared non-destructive device related to a wind turbine blade infrared flaw-detection robot. The robot can realize omni-directional scanning of blades with complex shapes and automatic quantitative identification of internal damage in blades. [PERSON] and colleagues, 2022 [91] showed a wind power generation blade defect-detection system comprised of a working device, where the working device comprises a main bracket, a walking mechanism, and a flaw-detection mechanism. Table 3 shows other patents that have been prospected that are related to the use of different techniques to identify faults in the wind turbine and its components. Figure 4: Analysis of the three main technological areas related to the inventions. Comparisons between the top filing company, Vestas Wind Sys As, and other companies, wherein ((**a**), pink) refers to wind turbine, rotor, and blade; ((**b**), blue) refers to additively, three-dimensional printing, additive, composite, build, and thermoplastic; ((**c**), purple) refers to testing, leakage, abnormality, monitoring, sensor, detecting, and inspection. In the center of the larger donut chart is the number of patent documents of the main applicant for a given technology and, in the smaller donut charts, the percentage of companies involved in the production of inventions related to this technology. The last indicator of the patent search performed: Figure 5 shows the main International Patent Classification (IPC) codes attributed to the patent documents found. The IPC code was declared in 1971 and is based on a hierarchical language of independent symbols for the classification of patents and utility models in accordance with the different areas of technology to which they belong. Of all the documents found, 241 were classified with the code F03D 17/00, which is related to the monitoring or testing of wind motors.