I.6.2 Commissioning

Function

Final commissioning is a set of mechanical and electrical checks and tests on the installed offshore wind turbine. It results in all systems having been put to work in a safe manner prior to handover of the installed floating offshore wind turbine to the client.

What it costs*

These costs are included in the wind turbine / substation supply contract.

Who supplies them

Final commissioning is expected to be split between the EPCI contractor for the array cable installation and hook-up, and the wind turbine supplier for the wind turbine.

Key facts

As much pre-commissioning as possible is performed on the various subsystems prior to offshore installation, to minimise the time and cost of final commissioning offshore.

The key steps in commissioning the offshore substation and cabling include visual inspection, mechanical testing, protection testing, electrical insulation testing, pre-energisation checks, trip tests and load checks.

Assuming grid connection to the turbine is complete, key steps in turbine commissioning include:

• Check of installation activity and documentation
• Mechanical and electrical completion
• Check of communication systems (SCADA, VHF radio)
• Energisation of all subsystems
• Testing of each link in safety and emergency system chains
• Exercising of all safety-critical and auxiliary systems
• Slow rotation of the rotor to confirm balance and smooth operation of the drive train
• Overspeed sensor and other safety-critical checks
• First rotation then first generation and checks on normal operation of all systems, and
• Checks on critical components and connections after a period of attended operation, then after a longer period of unattended operation.

If the installed offshore wind turbine has not been connected to the grid then final commissioning of the turbine can be carried out using a generator and a load bank, or power from a service operation vessel (SOV).

Even after first generation, it is routine to have several punch lists for each turbine and substation containing outstanding issues that need to be addressed before handover to the customer and operation, maintenance and service (OMS) teams. Handover will also normally require demonstration of performance and reliability over an agreed length of time.