Modern wind turbines operate continuously in remote, highly demanding environments. Exceptional reliability is essential as opportunities for maintenance are limited. Turbine rotation velocity is a key operating parameter and manufacturers require robust sensor systems that provide accurate measurement in real-time. Rugged presence-sensing systems withstand harsh exposed conditions, both onshore and offshore, while delivering the required accuracy and reliability.
A manufacturer of wind turbines provides engineering support for systems installed around the globe. The company’s field-service capability is backed by 24-hour remote data monitoring, allowing early detection of potential problems. Given the remote location of most wind farms, monitoring systems must be exceptionally reliable, as site attendance is infrequent.
Turbine rotation velocity is a key operating parameter, and the company requires robust sensor systems that provide accurate data in real-time. Traditional rotary-encoder technology is unsuitable as sensors do not withstand prolonged exposure to outdoor, often salt-laden, environments. In addition, turbine rotation speeds are relatively low, typically requiring more complex mechanical encoders.
The company requires a simple, contact-less system that provides fit-and-forget operation with extended maintenance intervals. Sensors must be mechanically robust and must withstand prolonged exposure to harsh outdoor conditions including seawater. An industry-standard interface is highly desirable to avoid the need for specialized control systems.
Rugged Full Inox inductive sensors from the Contrinex Extreme range are ideal for this application. Highly reliable and rated to IP68 or IP69K, these units provide a cost-effective alternative to tradition rotary-encoder technology. A one-piece M18-diameter AISI 304 (V2A) stainless-steel body and vacuum-encapsulated electronics make this device particularly suitable for the hostile environment, and the sensing distance of 10 mm allows fully contact-less operation.
A single sensor is mounted in each turbine head, immediately adjacent to the main mounting ring for the blade assembly. As the blades rotate, so does the mounting ring, and the sensor detects the presence of each mounting bolt as it passes the sensing face. The angular spacing of the bolts is known. Measuring the time that elapses between successive signals thus allows the rotation velocity of the blades to be calculated.
The sensor is configured with an industry-standard PNP normally-open interface, and connection to the turbine’s control systems is via an integral M12 connector and PUR-sheathed cable. This allows easy removal and replacement during routine maintenance. The sensor is corrosion-resistant and impervious to water ingress. Reliability has been excellent. Contrinex inductive sensors deliver a cost-effective solution that satisfies the customer’s requirements for a simple, fit-and-forget system.