2012-06-15 - 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.
Platform and turbines (Image courtesy DONG Energy)
The Walney offshore wind plant in the East Irish Sea has a total generating capacity of 367 MW (megawatts), 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 (megavolt ampere), 132/33 kV (kilovolts) 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 kilovolt (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.
Walney generator step-up (GSU) transformer
With an installed base of more than 1,400 units, ABB`s high-quality GSU transformers are working around the world in nuclear, coal, oil, gas, hydro, wind and solar generated power plants.
“GSUs enable wind-generated power to reach transmission networks, so this crucial equipment must be rugged and extremely reliable,” said Markus Heimbach, head of ABB`s global Transformers business, a part of the company`s Power Products division. “ABB has a global reputation for supplying state-of-the-art transformers and switching equipment for many power plant types, and is proud to be a part of this important low-carbon power solution in the UK.”
Walney`s 102 turbines generate electricity at a voltage of 33kV. Offshore substations collect the electricity from the wind turbines, and step up the voltage to 132kV for transmission by power cable to onshore substations and the UK national grid.
The Walney 1 offshore substation is connected to the national grid by a 44km long buried export cable at the substation in Heysham. At Walney 2, the offshore substation is connected to the national grid at Cleveleys near Blackpool, via a 43km long buried export cable.
The UK`s Department of Energy and Climate Change projects that about one fifth of the country`s existing electricity generation infrastructure will close over the next decade due to age, while electricity demand is predicted to nearly double by 2050.
Most of the country`s 90GW base load generating capacity is presently conventional coal, gas and nuclear power plants. Renewables like hydro, pumped storage and wind currently make up only a small portion of total capacity, but to meet its renewable energy and CO2
reduction targets the sector aims at decarbonizing electricity generation significantly in the next couple of decades.
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