Operation & maintenance |
Automated condition monitoring for wind turbines
For around 20 years Nabtesco Corporation of Japan has been involved in the engineering and manufacturing of yaw drive units for wind turbines. Now it has developed a condition monitoring system with fail-safe function (CMFS) that protects the yaw slewing unit against failure, helping to extend the service life of wind turbines and substantially reduce costs. A planned future enhancement of CMFS will see it combined with advanced sensor technology developed by Graz-based eologix
To achieve optimal utilisation of wind energy, the nacelles of modern wind turbines are equipped with yaw slewing units for alignment to the wind direction. High winds and turbulence can cause problems with the yaw slewing units due to excessive force or uneven strain. The result: premature wear; sudden failure; and high repair costs. Nabtesco Corp’s CMFS aims to address such problems. The system monitors the yaw slewing unit, detects abnormal conditions and automatically provides an even load distribution. The result: fail-safe wind turbines; and substantial reduction in repair, maintenance and operating costs. The CMFS consists of four components – bolt strain sensor, signal transducer, controller and power supply unit.
All models, brands and types of wind turbine can be equipped with a CMFS system, says Nabtesco, and the system is also designed for easy retrofitting in existing wind turbines, the company says.
The high-precision strain sensor measures the external forces, which are processed and analysed by the controller. If the values exceed critical parameters, the controller automatically triggers the electromagnetic brake on the respective yaw drive unit to reduce the load. This prevents damage to the yaw slewing unit. The system automatically saves all data to the cloud, so that the user can access real-time information on the load conditions via a PC, smart phone or tablet. The intuitive dashboard lists the operator’s wind turbines as well as each single yaw drive unit displays overloads to ensure constant and continuous monitoring.
The CMFS (Condition Monitoring system with Fail-Safe) from Nabtesco protects yaw slewing units against failure and can extend the service life of wind turbines (photo: Nabtesco Corporation)
One-fourth of all wind turbines are affected by sudden failure and yaw slewing unit problems within the first five years of operation, according to Nabtesco. Later functional impairments are caused primarily by material fatigue. The new CMFS is said to eliminate unplanned downtimes due to damaged yaw slewing units. Overall, Nabtesco says it wants to provide wind turbine manufacturers and wind power operators with products and services that will help them reduce their maintenance costs and increase proceeds from the sales of generated electricity.
Above: eologix sensor on a wind turbine blade
Collaboration with eologix Nabtesco expects further significant development of its CMFS system to be driven by a new collaboration with Austrian start-up eologix, developer of retrofittable smart sensors for wind turbines. The eologix sensors are highly rated in terms of reliability and “technological advantages”, says Nabtesco, and have already been employed on over 700 wind turbines in Europe. Through investment in eologix and business collaboration, Nabtesco says it plans to combine its CMFS technology with eologix status monitoring capabilities to develop “an advanced status monitoring system as well as a system to improve power generation efficiency.”
38 | March 2023|
www.modernpowersystems.com
A special feature of the eologix offering is its wireless and energy-autonomous sensor technology, which measures directly on the wind turbine rotor blade surface, and is capable of detecting very small changes in temperature, ice formation, imbalances, etc. The eologix sensors can be mounted almost anywhere on the rotor blades (and if required also on the tower and nacelle). The sensors monitor the operational status of wind turbines, including detecting icing on wind turbine rotor blades and flagging up blade pitch angle misalignments. Icing and pitch angle misalignments result in imbalance, which accelerates the wear of all components. This can be detected and avoided at an early stage by using eologix sensor systems, the company says. “On a wind turbine equipped with our sensor system, the turbine stops automatically in the event of safety-relevant ice accumulation on the rotor blades, and after an “ice-free” detection, the turbine re-starts automatically. In this way, turbine downtimes are reduced to a minimum – allowing more electricity to be generated from a single turbine,” explains Michael Moser, eologix CTO and co-founder.
As well as Nabtesco, other investors in eologix include Phoenix Contact Innovation Ventures, Emerald Technology Ventures and Orlen VC.
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