Software modelling highlights gearbox cracks

UNITED STATES: Large-scale operators of GE turbines are benefiting from a digital service that shows what is most likely to go wrong with the turbine's gearbox and when, as well as the best ways to prevent it.

Sentient Science uses its digital mapping of turbines and owners data to predict failures

Sentient Science appears to have taken the US wind power industry by storm since entering the sector in 2010. The software firm claims that the owners of 14,000 turbines across America, mostly the ubiquitous 1.5MW GE machine, are using its newly developed service to calculate how long their turbines have left to operate and what can be done to extend their working lives.

Sentient’s DigitalClone models the turbine and, looking specifically at the gearbox and bearing, calculates the earliest point of cracks and problems occuring in components. It then simulates the outcome of different solutions — such as replacing a part, re-rating the turbine through operations, or making an oil change — giving the owner valuable information on which they can they can base their decision.

A small company with a background in materials science, Sentient was pushed into wind’s direction by the US government, when it was commissioned and funded to take apart a Clipper 2.5MW Liberty turbine and simulate a digital model to learn about gearbox and bearing conditions and estimate potential repair needs. Faulty gearboxes in the model had cost Clipper dearly since the turbine’s launch in 2006, leading to concerns about the viability of the company’s warranty — a valid concern as it turned out.

By 2014 Sentient, having realised the value of its offering to the wind business, began to develop a simulation model for the GE 1.5MW turbine. The company offered its service to owners and operators of six to ten-year-old turbines, who were having to make the choice between extending the manufacturer warranty or taking responsibility for maintenance and repairs themselves.

Owners had been advised that their turbines would last 20 years, Sentient’s chief digital officer Edward Wagner told Windpower Monthly. "But now they were being told they would have to change the gearbox at least once, maybe twice, in that time, which changes the whole financial dynamic," he said.

"We came in and said: here are your options — up-tower repair, component replacement, oil change," said Wagner. "Each one has a cost, so simulate it first, try it out in the computers, so that you get the data to show you the right thing to do."

Sentient charges a flat rate of around $500 (€500 in Europe) per megawatt per year to monitor the gearbox and provide information on the turbine’s health and options for extending life. At this stage the service is mainly available for owners that have a fleet of more than 100 turbines. "They have the resources, the infrastructure and assets to make it valuable," said Wagner. But it does have some 

It takes about three months to build a digital clone, and Sentient plans to build up a library of turbine models, bringing its services to Europe. "The Vestas V80 and V82, and the 3.6MW Siemens offshore turbine are the natural ones to take next," he said. Sentient has also been visiting China, talking to developer Longyuan about modelling for some of its turbine gearboxes.

According to Wagner, turbine and gearbox manufacturers are also showing an interest now. "We represent the operator," he says. "We calculate the life of the gearbox using data from the owner operator. Now the OEMs and suppliers are coming to us to present the new work they have done." 

And Adwen, the Areva/Gamesa offshore joint venture, was the first to sign up the firm to assist with the testing of designs for its upcoming 8MW model. "We do testing in software, testing for the best design. So by the time the go to hardware testing, they have the best design possible," he says.