ABB power transformers and high-voltage products are helping to deliver enough clean, renewable electricity to supply up to 320,000 UK households per year, generated by one of the world`s largest offshore wind power plants about 15 km off the coast of Cumbria UK.
The Walney offshore wind plant in the East Irish Sea has a total generating capacity of 367 MW, consisting of 102 wind turbines with a rated generating capacity of 3.6 MW each. Newly opened in February this year, the installation is part of Britain`s effort to raise total offshore generating capacity from 1.5 GW (gigawatts) now to 18 GW by 2020.
ABB supplied the Walney wind plant with four 120-MVA, 132/33-kV generator step-up transformers (GSUs) for each phase of the project, two each for Walney 1 (51 turbines) and Walney 2 (51 turbines). Other essential ABB products installed in this major project include three 145 kV gas insulated switchgear (GIS) units and the main transformer surge arresters.
GSUs are essential links that connect power stations to transmission networks. They generally operate day and night at full load, and must be built to withstand the extreme heat and accelerated aging caused by constant high electrical currents.
Any breakdowns or interruptions in the electricity supply can be very costly for the plant owner. Walney offshore wind farm is owned by DONG Energy, SSE (Scottish and Southern Energy) and a consortium of investment funds.
In addition to high electrical currents, ABB designers must also consider magnetic fields, high-stress areas, oil flow and heat exchange in every part of the transformer windings to ensure each GSU unit delivers maximum efficiency and reliability.