Page 8 - Energize January 2022
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COVER STORY



                                                                                  costs, construction contracts, the location
                                                                                  of the project, infrastructure requirements
                                                                                  as well as numerous other factors outside
                                                                                  the scope of this document. For this
                                                                                  analysis the assumption has been made
                                                                                  that a utility-scale wind turbine costs
                                                                                  about R17-million per MW of capacity.
                                                                                    With replacement of the main
                                                                                  gearbox being approximately 10% of the
                                                                                  overall wind turbine cost, replacing a
                                                                                  3MW wind turbine gearbox could easily
                                                                                  exceed R5.1 million with transportation,
                                                                                  crane rental etc. Over the 20-year
        Figure 4: Typical wind turbine gearbox                                    expected life span of the wind turbine the
                                                                                  main gearbox is expected to be replaced
                                                                                  at least twice due to failure.
                                                                                    If the gearbox life could be extended
                                                                                  by even one year, the replacement costs
                                                                                  associated with the wind turbine life cycle
                                                                                  will be reduced by R510 000 per turbine.
                                                                                    Applying this savings to wind farm
                                                                                  with 50, 3 MW turbines equates to a
                                                                                  savings of more than R25-million over
                                                                                  the life cycle of the wind farm. The saving
                                                                                  does not take into consideration the
                                                                                  down time costs associated with loss of
                                                                                  electricity production which would be
        Figure 5: Downtime caused by failure in wind turbine sub-systems          validation for a proactive maintenance
                                                                                  programme of this nature.
        likelihood of failure through much of the wind turbine’s life cycle.        Oil analysis provides a solid
           Therefore, reliability is essential to the success of wind energy systems, and this requires   foundation on which to build an effective
        appropriate condition monitoring of sub-systems like the gearbox. Its is for this reason   condition monitoring programme in many
        that condition monitoring techniques like oil analysis are considered far more effective   applications. In the case of wind turbine
        predictive/proactive tools for achieving optimum gearbox performance as, in the case of oil   gearboxes, oil analysis has the potential
        analysis, the technique can be used to detect the onset of early damage as well as tracking   to reduce unscheduled maintenance,
        the severity of the damage.                                               improve reliability and extend service
           Routine oil analysis is one of the most widely used predictive / proactive maintenance   life. The oil analysis tests performed
        strategies for wind turbines and utilises a test slate that evaluates the condition of the in-  by WearCheck can help wind farm
        service lubricant and helps evaluate the condition of internal mechanical components. In   operators get maximum value from their
        short, routine oil analysis is used as a frontline defence against premature gearbox failures.  oil sampling program. When these tests
           The three main objectives of oil analysis are to monitor the health of the gearbox,   are performed on a routine basis and
        monitor the health of the oil and monitor contaminants. Active monitoring of the above   the results analysed by our experienced
        provides early warning of abnormal operating conditions that can lead to catastrophic   technicians, oil analysis can facilitate the
        failures if not corrected.                                                maintenance of wind turbine gearboxes
           These three objectives can be expanded to six main functions of an oil analysis programme   and ultimately, support this promising
        which are to: detect abnormal wear, detect oil degradation, detect contamination, optimise   form of power generation on the African
        service intervals, avoid loss of production and ultimately, to save money.  continent and beyond. Let WearCheck
           The test slate offered by WearCheck as part of their wind turbine oil analysis programme   help you maintain the assets that protect
        is designed to achieve these six main functions.                          our planet.
           To illustrate the potential savings that could be relalised with a proactive maintenance
        strategy like oil analysis, the below cost benefit analysis was performed.  Contact WearCheck, Phone 031 700-5460,
           The cost involved in installing a commercial-scale wind turbine can vary significantly   support@wearcheck.co.za,
        depending on the manufacturer of the turbine, the number of turbines, finance and legal   www.wearcheck.co.za



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