Power Transmission
during energisation. Pre-insertion resistors (PIRs) from Cressall are used as part of the safety control system on most UK and Irish wind farms. “PIR has not normally been associated with wind farm
generation collection systems at 33kV in the past, but is now fairly commonly used since some of our customers have pioneered it,” claims Martin Nicholls, sales director at Cressall Resistors.
transformers and as a consequence the resultant voltage drop at the point of connection with the utility. It is not in constant use all the time but is ready to protect the generating equipment when needed. Nicholls expands: “The turbines normally generate at 690V DC and the collection system on a wind farm goes to the substation through a transformer that raises the voltage to 33kV AC. The collection system terminates at the substation switchgear at which point it connects to the grid through our resistors.” The design of the Cressall PIRs has evolved over the last eight years using oval edge-wound coil elements such those as used in neutral earthing resistors in distribution substations in the UK and throughout the world. They are assembled in three-phase sets in single large stainless steel outdoor cabinets, sealed and equipped with IP54 cable boxes and anti-condensation heaters for the tough climatic conditions inevitably found at many exposed wind-farm sites.
Drivetrain testing
Summer 2013 will see the opening of a £35m 15MW capacity wind turbine drivetrain testing facility at Narec in Blyth, Northumberland. The main test hall will be completed by the end of the year and test rig components will then begin to be assembled onsite. The Energy Technologies Institute (ETI) is investing £25m
in the Narec facility, by providing funding to GE Energy Power Conversion and MTS Systems Corporation for the design, development and commissioning of the test rig. Steve Abbott, corporate affairs manager at Narec, says:
Fig. 3. Schaeffler’s FAG WiPro s condition monitoring system.
The wind farm is energised through the PIR which remains in circuit for a very short period of time. The PIR limits the magnetising inrush current produced by the turbine
Drivetrain commissioning H
GV Class 1 driver Paul Anderson writes: At 60 metres up from the
ground the crane lifts the huge 12 ton gearbox and disk brake assembly into position during construction of the Scout Moor Wind Farm, the largest onshore wind farm in England. It produces electricity from 26
Nordex N80 wind turbines, each with a generating capacity of 2.5MW, producing a total capacity of 65MW - enough power to supply the average needs of 40,000 homes. The engineer inside the nacelle is in contact by radio with the crane operator below. Construction of the wind turbines began
back in November 2007 at Turbine No 16. On 6th April 2008, Turbine No 25 became the very first turbine to begin generating. Early
42
www.engineerlive.com By June 2008 engineers had
constructed 26 wind turbine towers and installed 78 turbine blades 450 metres above sea level on Scout Moor amid adverse weather conditions of thick fog, gale force winds, torrential rain, snow and ice during the winter months of 2008. Commissioning and testing of the
turbines was the last stage, in which the electrical and mechanical systems were set-up, calibrated and fine tuned. The cabling works included the
on Sunday morning technicians from the turbine manufacturer Nordex connected a laptop as part of the commissioning process which monitors more than 300 different parameters like temperature sensors, hydraulic sensors, pitch parameters, wind sensor set and power output.
installation of many kilometres of fibre-optic cable, and linked from each individual turbine to a central supervisory control and data acquisition (SCADA) computer system which collects real time data from each turbine. Data from the turbines is logged and any faults that may occur with the turbines are recorded. ●
“We have already built and are now operating a 3MW test rig for tidal turbines. Our flagship 15MW facility is under construction and the test hall is nearly finished with the rig being assembled inside. We hope to commission the rig in April or May and to have the first test turbine in the summer.”
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