Condition monitoring for wind turbines

The complete condition monitoring solution for wind turbines – with extensive industry experience: The specialists at Brüel & Kjær Vibro offer a tried and tested monitoring concept specifically tailored to wind turbines. Our unique solution was originally developed many years ago in close cooperation with wind turbine manufacturers, operators and service departments. Yet we are independent of machine manufacturers, monitoring many different types of wind turbine generators. Now, our ground-breaking systems for remote monitoring are in use in thousands of wind power facilities.

The crucial quality advantage

  • Unique experience. Our diagnostics experts monitor more than 7,000 wind turbines. Their in-depth expertise is applied to each new condition monitoring project. Variable operating conditions, complex transmission and low rotational speeds – these factors all require a different monitoring approach to conventional rotating machinery.
  • Reliable fault diagnostics. If faults occur, it is essential they are discovered in good time. It is equally important to manage the flood of alarms and properly identify any false alarms. This can lead to considerable cost savings. That is why so many wind turbine operators rely on our condition monitoring system and service – a smart approach to your advantage.
  • Certified quality. Both our condition monitoring systems and our condition monitoring services are certified by Germanischer Lloyd.

Condition monitoring with modular service offerings

With Brüel & Kjær Vibro you will find the flexibility you need. Focused on you, our client, we adapt our service to your requirements.

  • Turnkey condition monitoring solutions
    Your one-stop shop: Together with our partners, we coordinate building, mounting and handing over of the systems as a fully operational solution. You will receive a turnkey system that is absolutely ready to go.
  • Customer-specific solutions. With our VibroSuite software package, your vibration specialists can use all monitoring and diagnostic functions without external support.
  • Combination of both solutions. Would you like to manage the operation and maintenance of your monitoring system and database server yourself? And still have access to diagnostic experts to assess your maintenance needs? Simply select the relevant components from our modular range of services.

Wind turbines are typically subject to high and varying loads, as well as extreme weather conditions. This can accelerate machine component degradation or at least make it unpredictable at best. In such a situation, adequate levels of machine uptime can only be achieved by rapid response times and fast service to correct the problems. Such an approach is difficult to implement, given the remote locations and the need for cranes and other external factors. This is even more critical for offshore wind parks where turbines cannot be reached during adverse weather conditions.

For this reason condition monitoring plays a vital role in a successful operation and maintenance strategy for wind turbines. A condition monitoring solution dedicated to the special requirements of monitoring a wind turbine is needed to take into account the special construction of these machines and their operation:

  • Low rotational speeds
  • Complex gearbox structure
  • Non-rigid foundations
  • Compact construction
  • Continuously changing wind conditions


Such a system not only has to accurately detect a number of developing faults that are unique to wind turbines, but it also has to avoid the flood of alarms that can often occur while monitoring the wind turbines. Some of these alarms can be due to changing operating conditions, and therefore the condition monitoring system requires an effective power class monitoring strategy for reducing these types of false alarms. Often there are many alarms generated for the same, single fault due to the compact construction of the wind turbine drive train, so an intelligent alarm management system is also needed to reduce these types of redundant alarms.

Early fault detection with proper alarm management significantly improves the accuracy and reliability of the condition monitoring strategy, but it is still not enough for many applications. Fault diagnosis expertise is necessary for not only for identifying the type and location of the fault, but also for determining its severity and establishing a lead-time to failure. Such expertise is hard to come by, and many operators do not have it.

These are some of the primary underlying concepts from which the Brüel & Kjær Vibro wind turbine condition monitoring system solution was built upon.

With more than 60 years in the monitoring business, we have gained solid expertise in detecting and diagnosing potential failure modes at an early stage of development for all types of machines and applications, including wind turbines.

As our monitoring strategy is primarily focused on the drive train portion of the wind turbine, most of the potential failure modes are associated with the rolling element bearings, gears and the generator.

Although the fault detection techniques for these components are not new, the means to detect these faults present challenges due to the wind turbine design and operation concept. The widely variable operating conditions coupled with non-rigid foundations, compact construction, complex gearbox and low rotating speed require an entirely different monitoring approach for wind turbines.

Important monitoring functionality that enables a wind turbine monitoring system to detect and isolate developing machine faults includes:

  • Process bins (see  Machine Monitoring Strategy)
  • Alarm management (see Machine Monitoring Strategy)

Monitoring strategy

Vibration measurements, process parameters and speed/phase information on the machine components.

  • Gearbox 1st, 2nd & 3rd Stage Failure Modes:
    Gear Defects: Looseness, Gear Wear, Gear Tooth Faults
    Bearing Defects: Lubrication, Misalignment, Looseness, Race and Cage Defects
    Shaft Problems: Unbalance, Misalignment
  • Low Speed Shaft & Main Bearing Failure Modes:
    Rotor, Unbalance, Bent Shaft, Lubrication defects, Bearing Looseness, Bearing Defects
  • Generator DE & NDE Failure Modes:
    Lubrication Defects, Bearing Misalignment, Bearing Looseness, Bearing Defects, Shaft Unbalance and Misalignment, Bent Shaft, Looseness, Coupling Faults, Support Structure Changes, Electrical Faults
  • Structural Failure Modes:
    Support Structure Changes, Gearbox Suspension Defects, Resonances

System for distinguishing a change in vibration due to process changes, such as active power, from that due to developing faults.

The effectiveness of a monitoring system lies in the ability to detect developing faults at an early stage, without generating false alarms, despite speed and load changes. Our wind turbine monitoring system enables the user to identify relevant process classes where the vibration signature is distinct, in order to set up individual alarm limits that correspond to these process classes, as shown in the figure below. This prevents incorrect alarming.

  • False alarms – Caused by vibration changes due to operation changes, not machine faults
  • Absence of alarms – No alarm is generated despite the presence of a developing fault, because the alarm limits were too high
Process bin concept
Picture Of Process Bin Concept

Intelligently reduces the flood of alarms that often occur when monitoring wind turbines, due to variations in operating conditions. 

As there can be 1000+ alarm limits per turbine, one of the greatest challenges of monitoring a wind turbine is dealing with a potentially large number of alarms and determining which alarms are relevant. There are also many transient events during the operation of a wind turbine, such as gusting and yawing. These transient events can actually cause the exceedance of an alarm limit for a shorter period of time even though there is no component fault. Another area of concern is localizing a developing fault. A fault that has been detected by a sensor on a particular bearing, for example, can also be picked up by other nearby sensors. In this case there is only one machine fault but many alarms.

Brüel & Kjær Vibro introduced an intelligent alarm management system that scans this flood of alarms and filters out those that are not relevant. It also filters out alarms due to transient effects. It filters the alarms such that one physical fault has only one alarm.

The alarm information is graduated into five severity levels in order to provide the customer’s service department with a lead-time estimate on a developing fault, as shown below. New alarms are generated only when a new severity level is reached. There are therefore only a maximum of 4 alarms for the “lifetime” of the fault. Severity is first estimated automatically by the Alarm Manager, and then a final assessment is made by a diagnostic expert.

Alarm Class Description
Picture Of Alarm Class Description

Monitoring system & services

Picture of system overview turnkey solution
1. Hosted turnkey solution
Picture of system overview customer-owned solution
2. Customer-owned solution
Picture of monitoring system overview of customer-owned solution with B&K Vibro services
3. Customer-owned solution with B&K Vibro services

1. Hosted Brüel & Kjær Vibro Turnkey Solution
If machine monitoring is not one of your core business functions, you can still benefit from complete monitoring coverage as an external turnkey solution. Our comprehensive service includes all monitoring and diagnostic functions as well as the operation and maintenance of the monitoring hardware, software and servers. We simply deliver maintenance recommendations to your service group with ample lead-time.

2.  Customer-owned solution
With a well functioning condition monitoring and IT group, it will be possible for you to operate and maintain your entire monitoring system and database server on your own, completely independently of Brüel & Kjær Vibro. Our Vibro Suite system allows your vibration specialists to take care of all monitoring and diagnostic functions without outside assistance. No services are needed from Brüel & Kjær Vibro in this situation.

3.  Customer-owned solution with Brüel & Kjær Vibro Services
Maybe you have the means to operate and maintain the monitoring system and database server, but are lacking the diagnostic expertise to make accurate service calls. We can provide services to help you here!

As an authorized user, you get an overview of the condition of the wind turbines in the park via an Internet browser. All wind turbine alarm, vibration and process data can be accessed from the website in order to get an overall status on the condition of the wind turbines as well as viewing detailed alarm information at specific measurement points in a given wind turbine. This homepage function provides transparent access to the condition of the turbines and the diagnostic expertise used.

CMS User Homepage Screenshot 1
CMS User Homepage 1
CMS User Homepage Screenshot 2
WTG Analyser Screenshot 2
Screenshot Of WTG Analyzer

This diagnostic program allows you to view vibration and process data in the Brüel & Kjær Vibro Surveillance Centre database server at every measurement point for each wind turbine in your wind turbine parks. It also allows you to download high-resolution time waveforms so you can do your own post-processing diagnosis and analysis.

WTG Analyzer Screenshot 1
Screenshot Of WTG Analyzer

We now also offer a Condition Monitoring Solution as a Service (CMSaaS) - a complete retrofit condition monitoring solution for wind turbines without the financial burden of upfront capital investment. Read more in our press release or contact us for more information.

The Brüel & Kjær Vibro surveillance centre consists of a team of ISO 18436 certified diagnostic specialists dedicated to monitoring wind turbines. In addition to facilitating and optimising the diagnosis of incipient faults, the centre establishes clear procedures for integrating the information and workflow between the surveillance centre and the operator service departments. Data from all the wind turbines is sent by the data acquisition units in the nacelle of each turbine to the central data acquisition server and database. An advanced alarm management system in the server compares the data to pre-defined limits, intelligently reduces the flood of alarms that normally occurs because of wind gusting, cross-signal transmission, etc. to prioritise and then issue qualified alarms.

In the event of alarm data, time signals are downloaded from the respective wind turbine for post-processing and analysis. The Brüel & Kjær Vibro Surveillance Centre then issues alarm reports to the customer’s service department. When wind turbine components are serviced, feedback is given to the Surveillance Centre so diagnostic techniques, severity assessment and lead-time evaluations can be evaluated and further fine-tuned.

The Surveillance Centre also takes care of the monitoring hardware in the wind turbines.

The Brüel & Kjær Vibro reports are well respected within the industry due to their accuracy, brevity, and the manner in which complex information from the condition monitoring system is synthesized into easy-to-understand and actionable information.

Diagnosis of detected potential failures are summarized in the Alarm Report which contains:

  • a description of what has been observed
  • an interpretation of the observation and
  • an assessment of the related maintenance needs.

References

  • Broken Bow II in Nebraska/USA with the size of 75MW
  • San Marcos in San Marcos de Colón/Honduras with the size of 50 MW
  • Chinchayote in Tegucigalpa/Honduras with the size of 45 MW
  • Cerro de Hula in Departamento Francisco Morazán/ Honduras with the size of 100 to 126 MW
  • Frosolone in Frosolone/Italy with the size of 6.8 MW
  • Caltavuturo in Sicily/Italy with the size of 47.6 MW
  • Sedini in Sardegna/Italy with the size of 31.5 MW
  • Trapani in Sicily/Italy with the size of 8.5 MW
  • Horns Rev 1 in North Sea/Denmark with the size of 160 MW
  • Erie Shores in Ontario/Canada with the size of 99 MW
  • Gamesa G52 0.85 MW
  • Gamesa G87/2000 2 MW
  • GE 1.5 MW
  • GE 1.7 MW
  • GE SL and SLE 1.5 MW
  • Repower MM92 2.05 MW
  • Vestas V80/2000 2 MW

  • Vestas 90 3MW

  • V80-110 1.8 – 2 MW

  • V112 3.3MW

  • S88 2.1MW

Products we use for our condition monitoring solutions

  • Flexible, fast, reliable: Data acquisition platform for more than protection

    Integrates data from any protection system for Condition Monitoring.

    Powerful software package for secure wind turbine monitoring

    Precise acceleration, vibration speed and non-contact displacement sensors

  • Scalable solution beyond machine protection for plant-wide condition monitoring

    The 16-channel system for scalar data reporting and early fault detection

    The allrounders for machine diagnostics, balancing and condition monitoring

    High-quality accessories form the perfect complement to your monitoring solution