After the turbine caught fire on 4 August, pictures were shared on social media showing its nacelle completely burned out and an investigation was launched into the cause of the fire.
The faulty component was located inside the prototype’s converter module and was "unique to a prototype environment", MHI Vestas said following an inquest by an independent investigator.
The component had a "solid track record" and was only added to the prototype to test the turbine’s future upgrade to 9.5MW, the manufacturer added.
The prototype satisfied the requirements for the 9.5MW type certification prior to the incident, MHI Vestas added, and plans for building a new prototype are being discussed.
Torben Larsen, MHI Vestas’ chief technology officer, said: "The incident on 4 August occurred as a result of testing that was directly related to the turbine’s future upgrade to 9.5 MW.
"While unfortunate, the situation was handled safely and professionally by our technicians on site.
"Since August 4, we have been in frequent communication with our customers and have worked tirelessly to find the root cause and implement the right mitigation actions.
"We are confident that all procedures and processes in relation to this have been thoroughly and properly updated."
MHI Vestas had installed the turbine, which has had power ratings of between 8MW and 9.5MW, at the Danish test site in 2014.
An 8MW version of the turbine was first installed at Ørsted's (formerly Dong Energy) Burbo Bank Extension site in the Irish Sea. An uprated 8.25MW version of the turbine is also featured at Ørsted’s Walney Extension West wind farm, also in the Irish Sea.
Five 8.3MW V164 models are being installed at the Blyth test site off the north east coast of England.
And and the latest 9.5MW version has been named the preferred turbine for the 950MW Moray East site off the east coast of Scotland and Innogy's Triton Knoll project off eastern England.
The V164-9.5 model’s gearbox and main bearings are to be tested at Clemson University’s 15MW test bench in South Carolina, MHI Vestas announced last month.
