• Can machines also stay young longer?

SHM.Tower – System for vibration monitoring and life cycle prognosis

Intelligent monitoring system for tower vibrations on wind turbines

Windfarm offshore
Windfarm offshore

A careful and economically optimized operation thanks to the individual setting of operating parameters and performance curves for each wind turbine (WT) in your wind farm can only be realized with actually recorded vibration data. The monitoring system SHM.Tower® has been developed to continuously record this vibration stress in your tower. With the integrated evaluation routines, e.g. warnings can be issued when threshold values are exceeded, thus providing a significant added value during operation. WTs under excessive stress can be immediately identified and countermeasures can be taken.

Direct Ioad measurement
The aim is to compile the Ioads recorded during the measurement period in a Ioad spectrum and then extrapolate the Ioad collective for the past and future operating years, and to use it as input values for analytical method. The Ioad measurements are a test procedure for the practical method. A continuous Ioad measurement has the advantage that deviations from the expected operating Ioads are detected at early stage.

The Ioads shall be measured directly at suitable points using suitable methods.

A distinction shall be made between:

  • Load measurements Iasting several weeks to several months, mainly in order to supply input or validation data for the analytical method or assess lifetime extension using statistical extrapolation.

  • Permanent operational load measurement at the WEC in order to extrapolate the Ioad collective for past/future operating years from it using analytical calculations and derive the possible lifetime extension period. lnthis way, future changes in the external impacts on the WEC are also completely included.

Source:
Basic Principles for Performing an Assessment and Verification of the Lifetime Extension of Onshore Wind Energy Converters (BPW)

Lifetime prognosis for assessments regarding further operation as well as in the context of a technical due diligence

Lifetime prognosis per tower segment
Lifetime prognosis per tower segment

During the entire service life, the stored and directly evaluated data provide exact information about the consumed lifetime. With the use of SHM.Tower® in your tower, the evaluation for further operation of your wind turbine is based on the fatigue loads that have actually occurred and not only on mere estimations. For an extension of the operating time, especially the critical extreme conditions are directly recorded.
Sensors and electronic equipment of SHM.Tower are installed in a compact casing for easy installation in the tower head of the wind turbine. In the energy self-sufficient operating mode, SHM.Tower can be integrated during construction and can thus bridge short-term power failures. Furthermore, the system can also be retrofitted on an existing turbine: all fatigue loads are recorded and stored at any time.

Functions

Monitoring function

  • Measurement of vibration stress and output of warnings if threshold values are exceeded (ISO 10816-21/VDI 3834)
  • Frequency distribution of RMS values (e.g. during the year)

 

Lifetime prognosis

  • Lifetime prognosis for each tower segment by based on fatigue strength
  • Classification of loads according to operating conditions
  • Lifetime consumption trend
  • Valid statements for the further operation of your wind turbine
  • Also for retrofitting
Vibration monitoring system SHM.Tower
Vibration monitoring system SHM.Tower

 

Performance

    • Energy self-sufficient monitoring function (recording up to 3 months without energy supply)
    • Connection to the Wölfel monitoring portal MIC.Wind
    • Interface for external sensors (three-channel sensors)
    • Frequency range: 0,1 – 10 Hz
    • Measuring range: ± 2 g

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