With a bigger need for renewable energy offshore windfarms are increasing rapidly all over the world. Today all the bolt and nut maintenance is made by on-site technician teams going out with equipment either by boat or helicopter. The fickle weather conditions together with high risk procedures make it sometimes difficult for the maintenance teams to reach the windfarms, leaving wind turbines unattended during rough sea.
WASP is an autonomous bolt and nut maintenance solution which is installed together with the wind turbine and will continue to operate throughout the turbine's life cycle. All bolt and nut maintenance is overseen and documented through live-feedback to onshore operators. Independent of weather or time of the day. Without the need for on-site personell WASP is saving both time and money and eliminates the risks.
The project in cooperation with Atlas Copco is about the operation of precision tightening and loosing heavy duty bolts mainly for the oil and wind turbine industry.
The tools used today are for example hydraulic tensioners, torque wrenches and nut runners. Because these tools operate in extreme fields such as oil platforms and wind turbine assemblies with high precision it also demands a lot from the users. This project's goal provide user centred solutions to improve the work experience and also explore the design opportunities in these set fields.
The initial part of the research was composed of visits to different companies working with heavy duty bolt and nut tensioning solutions for various purposes. The idea was to talk directly with the people working with these tools to get a better understanding of how they work and what might be the current limitation of the tools.
During the visit at Atlas Copco in Nacka, Stockholm we had the chance to talk to the engineers behind the tools. We were given presentations of the tools concerning the project with specifications and handling demonstration. We were also given a look into the ergonomics work of Atlas Copco.
kNm Hydraulikk, stationed in Stavanger, Norway is Atlas Copcos supplier of bolt-tightening tools in Norway. At their headquarters we had the opportunity of observing demonstrations of different tools made by an bolt operator working at a variety of oil platforms in Norway.
Wepco, Stavanger, Norway is a service workshop for the Norwegian oil industry and mainly service gas pipe gasket and such. During our visit we had a presentation of which tools they use for their daily work.
While looking into off-shore wind turbine bolt tensioning during the initial research the maintenance work was brought up. Looking further into the work flow of the service technician it became clear that some conditions had to be met for it to possible carry out bolt & nut maintenance. These conditions could also be seen as pain points in the daily routines for the technicians.
- Time; A wind turbines takes 6 operators 12h to inspect & service
Cancelled or delayed maintence due to harsh weather conditions
Maintenace technicans are faced with a dangerous work environment
Technicans must have substantial training to understand all aspects of the technology and safety
To get to off-shore wind turbine parks the team must travel by boat
Working in groups of 6 people per each team only two teams can fit on the boat
All of the factors above is being accounted for during a maintenance operation of a wind turbine. A lot of conditions need to be met for a successful operation. When looking over these condition it became obvious that the common denominator is the operator, the service technician. The simple conclusion of by removing the operator's need to go out to the wind turbine also eliminated many of the earlier mentioned conditions.
Considering a maintenance system without the need of operators two different units took shape. At this early stage none of the units had nothing more that functions. The first unit was a operating unit, which was doing the physical work of maintaining the bolts in the wind turbine tower. The second unit was a communication unit that received and dispatched information between the operation units and a supervisor on-shore. These two types of units would be placed inside the wind turbine at the time of assembly and last the whole wind turbine's life cycle (approximately 20-30 years).
This way the documentation of bolts and nuts would be performed at the same time as the maintenance and sent to a database located on-shore. The system would be immune against rough weather conditions. It would also spare the need for education, safety equipment, transport, long working hours and avoid placing service technicians in potentially hazardous situations.
WASP or Wind Turbine Automatic Service Protocol is a tool that is assembled together with the wind turbine and will last the whole wind turbine's lifecycle. WASP's purpose is to perform maintenance on the bolts and nuts in wind turbine's tower flanges. The tool will mainly replace today's off-shore wind turbine park service teams that go out to the wind turbines by boat.
WASP is mounted on a rail of the wind turbine tower´s inner structure above the flange connecting it with another tower section piece. Slowly and steady working it through all of the 200+ bolts fastened over the flange WASP is using ultrasonic sensor measuring the tension in each bolt and evaluating if it needs re-tightening or not. If needed it uses a hydraulic tensioner to radially stretch the bolt while electric motors tensions the nut to preferred tension. All data collected through the process is sent to on-shore operators, which supervise and manage the data.