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Condition Based Maintenance of Vestas Offshore Turbines

European Offshore Wind Conference & Exhibition 2009, StockholmJacob Juhl Christensen, Product Manager

2 | Condition Based Maintenance of Vestas Offshore Turbines, April 19, 2023

Agenda

• Condition Based Maintenance enabled by Condition Monitoring

• Technical and operational challenges in fleet-wide implementation

• Practical implementation of condition based maintenance in service organisation

3 | Condition Based Maintenance of Vestas Offshore Turbines, April 19, 2023

Condition Based Maintenance enabled by Condition Monitoring

• Condition Monitoring: Assessment of the "health" of a machine by analysis of measured signals (vibration, temperature, …)

• Estimation of time of failure optimised planning of maintenance activities

Breakdown(Ad Hoc)

Preventive(Scheduled)

Predictive(Condition based)

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Condition Monitoring

4 | Condition Based Maintenance of Vestas Offshore Turbines, April 19, 2023

Condition Monitoring System

• Measurement system on WTG Drive Train:

5 | Condition Based Maintenance of Vestas Offshore Turbines, April 19, 2023

Condition Monitoring Information Flow

6 | Condition Based Maintenance of Vestas Offshore Turbines, April 19, 2023

Fault detection by historical trending of Fault Symptoms

• Failure modes• Bearing Faults

• Coupling Faults

• Misalignment Faults

• Gear Faults

• Unbalance

• Support Structure Faults

• Examples of trended parameters

• Overall RMS

• High Frequency Bandpass Values

• Tooth Mesh Frequencies

• Bearing Frequencies

• etc.

7 | Condition Based Maintenance of Vestas Offshore Turbines, April 19, 2023

How to achieve cost efficient condition monitoring on a large and geographically dispersed fleet ?

• Technical Challenges• Events in each turbine can

lead to a cascade of alarms• Requirement: only one alarm

per detected fault/severity level

• The severity of all alarms must be assessed

• Need for automated alarm management

• Operational Challenges• Site managers need clear

advice about how to plan service actions according to alarm severity.

8 | Condition Based Maintenance of Vestas Offshore Turbines, April 19, 2023

Automatic Alarm Management – NO Alarm Flooding

• Reliable fault detection requires monitoring of 1000+ alarm limits per turbine.

• Alarm Flooding is avoided by filtering the fine grained alarm information down to one single alarm notice per physical fault.

• The Severity of the potential damage is estimated by the Alarm Manager from the indications in the alarm pattern.

• Final severity assessment performed by a diagnostic expert

9 | Condition Based Maintenance of Vestas Offshore Turbines, April 19, 2023

Severity classification – Actionable information

• Alarms are classified according to severity• New alarms are issued only when a new severity level is reached• A maximum of 4 alarm notices will be issued during the “lifetime” of a

fault• Each severity class specifies a lead time until recommended service

action.

10 | Condition Based Maintenance of Vestas Offshore Turbines, April 19, 2023

Reporting – Clear advice about severity and estimated remaining life time

• Diagnose of detected potential failures are summarized in an Alarm Report

• Fixed report format with clear split between

• Observation• Interpretation• Assessment of maintenance needs

11 | Condition Based Maintenance of Vestas Offshore Turbines, April 19, 2023

Planning of service actions according to alarm severity

• Due to high mobilization costs, unnecessary turbine visits must be avoided.

• Rules for when to perform a turbine inspection as function of the alarm severity class must be defined.

Severity Type Planning of inspection

1 Danger Within 24 hours or remote stop until access possible

2 Alert ASAP (within two weeks)

3 Alert Next scheduled visit

4 Alert Next scheduled visit

5 Good No action

6 System Next scheduled visit

12 | Condition Based Maintenance of Vestas Offshore Turbines, April 19, 2023

Summary

Condition Based Maintenance on offshore turbines requires

• Online Condition Monitoring systems

• Automated Alarm management

• Alarms transformed into actionable information

• Planning of service actions according to alarm severity

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Thank you for your attention

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