Ensures there is no interruption to transmission from electrical failures or structural problems with the offshore platform.

Who supplies them

High voltage electrical contractors: ABB, GE, Schneider Group and Siemens Power Transmission and Distribution.

Offshore contractors: Deutsche Windtechnik, Petrofac.

Key facts

Monitoring and maintenance of the offshore substation primarily consists of non-intrusive inspections of topside switchgear and transformers, sampling of transformer oil, foundation and topside structural inspection and resulting infrequent repair interventions (see B.4 for further information).

The owner carries out paint repairs and secondary steelwork repairs (for example to railings, gratings, gates, stairs, and ladders).

Serious repair operations, such as replacing transformers, require heavy lift vessels.

Rapid turnover parts and consumables are stored in a large warehouse at the onshore base.

Back-up diesel generators require periodic maintenance and refuelling.

Access to the substation may be by vessel or helicopter but since few failures require urgent attention, the weather downtime of vessels may not be as important a consideration as it is for turbines. During planned power outages to support detailed inspection and maintenance operations, careful planning is required to ensure weather windows are used to avoid excessive wind farm downtime if work cannot be completed and assets re-energised.

Onshore substation maintenance comprises non-intrusive inspections of switchgear, transformers, and any reactive power compensation equipment (see B.5 for further information). Infrequent repair in response may be required.

Unlike many of the systems of an offshore wind farm the onshore substation is almost entirely non-offshore wind specific, consisting of standard high-voltage electrical equipment.

What’s in it

Guide to a Floating Offshore Wind Farm