Online condition monitoring of turbines at wind farm

In May 2012, FOR installed five FAG WiPro s condition monitoring systems from Schaeffler on five wind turbines at the Crystal Rig wind farm in Scotland. These systems continuously monitor the condition of the main rotor bearings, gearbox and generators, with Schaeffler UK also providing remote monitoring services on a 24/7 basis.

Crystal Rig wind farm is located on the Lammermuir Hills, approximately 40km east of Edinburgh in the Scottish Borders. When Crystal Rig wind farm commenced operations in October 2003, it was the largest onshore wind farm in Scotland, with a rated output of 50MW. The hub heights of the Phase 1 wind turbines are 60m with a rotor diameter of 80m.

In phase 2, a further five wind turbines were installed at Crystal Rig, bringing the total number of turbines to 25, generating a total capacity of 62.5MW from May 2007.

Stuart Naylor, Operations Manager at Fred.Olsen Renewables UK comments: "We are delighted with the condition monitoring systems and remote monitoring services provided by Schaeffler and we look forward to continuing and further developing this working relationship in the future. Back in September 2011, when we were looking for a suitable UK-based supplier, we found Schaeffler to be extremely professional and competitive, as well as demonstrating confidence that their system could provide us with the most suitable condition monitoring system. Additionally, Schaeffler offered flexible training, remote monitoring and reporting services to meet our requirement."

Schaeffler's FAG WiPro s is an online condition monitoring system that is suitable for the permanent monitoring of wind turbines. The system is very compact, with the monitoring unit and multiplexer integrated in a single unit, which offers a high degree of flexibility for end users.

The system combines all control modules into a single compact housing, which measures just 260 × 150 × 90mm, enabling easy installation in control cabinets. The integrated multiplexer enables the recording of signals from up to eight different sensors.

FAG WiPro s monitors vibration conditions which, if left undetected, can cause costly unplanned shutdowns of wind turbines. These conditions include damage to bearings and gears, as well as shaft misalignments. If a specified threshold value or alarm limit is exceeded, the system triggers an alarm. The vibration monitoring data can be analysed directly on site at the central control station, or this data can be retrieved via a TCP/IP communications link and analysed by either the end user or by Schaeffler. Integration of oil quality (particles) as part of the monitoring is also possible.

24/7 vibration data

Dr Steve Lacey, Engineering Manager at Schaeffler UK, says: "On each of the five wind turbines being monitored at Crystal Rig wind farm, we've installed six vibration acceleration sensors. One of these sensors is a special low-frequency vibration sensor that monitors the main rotor bearing, and there is also a low-frequency vibration sensor on the input shaft to the gearbox. Two additional standard vibration acceleration sensors are installed on the power train gearbox, with a further two vibration sensors on the generators. These sensors provide us with 24/7 vibration data - including both time-based and frequency-based vibration data - which enables us to look for faults or to detect problems early.

"Since the condition monitoring systems were installed in May, we've picked up a couple of faults in the generator bearings and identified early problems with some gears on a planetary gearbox. These faults were confirmed by Fred.Olsen by using fibre optic cameras [endoscopes] to look inside the gearbox," he added.

For more information on Schaeffler's condition monitoring systems for wind turbines, please email [email protected], or visit the website at www.schaeffler.co.uk.