Install and maintain hydraulic systems on wind turbines

Business Sectors (Suites): Wind Turbines
Developed by: Energy & Utility Skills
Approved on: 01 Dec 2017


This national occupational standard defines the competence required to install, test and maintain hydraulic systems on wind turbines. It also requires competence in reading and interpreting technical drawings. The standard is for those responsible for installing and maintaining hydraulic systems on wind turbines whether they are situated onshore or offshore and requires knowledge and competence of the use of a variety of mechanical methods.

Performance criteria

You must be able to:


  1. Identify the hydraulic system to be isolated by interpreting system

    plans and using available information.

  2. Select and wear the PPE required to carry out the isolation activity.

  3. Apply isolations and prove for dead in accordance with local isolation


  4. Carry out a site-specific risk assessment of the work area, identifying

    the hazards and implementing the control measures required.

  5. Maintain accurate and up to date records.

  6. Report information and data to the designated person.

    Maintain Hydraulic Systems on Wind Turbines

  7. Use and interpret technical drawings.

  8. Check all aspects of the operation of a hydraulic system and identify


  9. Undertake checks and routine activities as part of a planned

    maintenance programme.

  10. Install a system to comply with manufacturer and company


  11. Commission the hydraulic system and confirm safe and correct


  12. Carry out the operation, troubleshooting and commissioning of PLC

    and Safety Constrollers

  13. Carry out inspection, testing and fault finding on fluid power


  14. Strip a system to component level and repair or replace as required.

  15. Confirm that the completed task meets expected Company


  16. Clean and store equipment safely and securely and leave the work

    area in a safe condition in accordance with Company procedures.

  17. Carry out all work in accordance with industry standards and


    Mechanical Specific

  18. Safely dismantle, assemble and tension:

    a) bolted connections.

    b) hydraulically torque bolted connections.

  19. Inspect and check components and fittings.

  20. Check and confirm that work complies to related specifications,

    methods, process, techniques and company and manufacturers


  21. Carry out drive alignment using hand tools.

Knowledge and Understanding

You need to know and understand:


  1. The principles of health, safety and environmental legislation and

    regulations when maintaining hydraulic systems, including COSHH


  2. The organisation's safety rules, policies and procedures when

    carrying out work on hydraulic systems.

  3. The hazards associated with hydraulic systems, including portable

    systems, and the means by which they are minimised.

  4. How to select, inspect and use PPE when carrying hydraulic system


  5. How to carry out a site specific risk assessment and identify

    workplace hazards.

  6. Assessment of the role and criticality of the hydraulic system in

    relation to site and process.

  7. How to identify different hydraulic motors and controllers.

  8. The symbols that represent fluid power devices in circuit diagrams.

  9. The identification of different types of valves, pipe work, sensors and


  10. The identification of schematic symbols for hydraulic systems.

  11. How Can-bus, Ethernet and Profinet networked systems work and

    interface with the hydraulic pressure pump.

  12. How to respond in the event of an emergency situation in the

    workplace environment.

  13. How to leave the work area in a safe and secure condition,

  14. The company recording and reporting process.

    Maintain Hydraulic Systems on Wind Turbines

  15. the principles of Hydraulic systems, including the construction and

    operation of fluid power devices.

  16. the function of all hydraulic system components, including:

    a) actuators

    b) valves

    c) accumulators

    d) sensors

    e) use of remote diagnostic tools to aid fault finding including HMI

    screens and SCADA systems

  17. the function of different types of pumps and how to check start/stop

    pressure of a pump.

  18. De-pressurisation of a hydraulic system.

  19. How to select and change system fluid, flushing when necessary.

  20. How to select and change system filters.

  21. Removal and replacement of static and dynamic seals.

  22. The sequence to be adopted for the dismantling and reassembling

    of the equipment to both sub assembly and component level.

  23. Methods of checking that components are fit for purpose.

  24. How to change hydraulic hoses, fittings and pipe work.

  25. How to adjust components and assemblies and flows and pressures

    to ensure they function correctly.

  26. The correct means of disposal of contaminated waste from work on

    hydraulic systems.

  27. The sections of current British Standards relevant to your work.

    Mechanical Specific

  28. How to use measurement techniques including:

    a) Vernier gauges

    b) Micrometers

    c) Calipers

  29. The principles and regulations relating to torque and angular


  30. Hand torque bolted connection techniques.

  31. The cause and effect of good and bad drive alignment.

  32. The principles of laser alignment,the laser equipment used for

    alignment and how to correctly use it.

  33. The types of materials available and how to select material

    appropriate for the task.

  34. How to recognise stress relaxation, fatigue and the effects of


  35. The principles of lubrication and types of lubrication and



Scope Performance

Scope Knowledge





Links To Other NOS



External Links

Version Number


Indicative Review Date

01 Jan 2021





Originating Organisation

Energy & utility skills

Original URN


Relevant Occupations

Engineering, Science and Engineering Technicians

SOC Code



Environment; Plant; Utilities; Wind turbines; Engineering; Hydraulic