UK Wind Farm Interference Leads to Radar Replacement
One of the problems with wind farms is the effect of their turbine blades on air traffic control and defense radars. Wind turbine blades have extremely large radar signatures, especially when grouped in a farm, and their movement creates doppler effects. This generates massive amounts of radar “noise”, and a “shadow” region behind the wind turbines. “2D” radars that don’t use multiple vertical beams are especially prone; unfortunately, many air traffic control radars fit that profile.
Britain is especially interested in wind farm power, and this drawback posed a significant problem. They’re beginning to respond by buying new long-range radars from Lockheed Martin, for emplacement near wind farms. These moves follow a 2005 report [PDF] that concluded:
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“Flying over or in close proximity to a wind turbine can significantly hamper the ability of an ATC (Air Traffic Control) operator to maintain the identity of his own aircraft and is also unacceptable in the context of the safe provision of ATS(Air Traffic Sarvices)…”
Some air defense radars were also affected, and until recently, the UK Ministry of Defence had objected to wind farms located near Air Defence Radars. After some research, however, they concluded that Lockheed Martin’s widely-used AN/TPS-77 long-range air defense radar was likely to be “wind farm friendly.” A contract was issued to Serco, who installed a TPS-77 radar near Cromer, on the Norfolk coast. UK MOD Defence Equipment and Support (DE&S), and the Department of Energy and Climate Change were also involved, and following tests, the UK MoD has dropped its objections to 5 proposed wind farms in the area.
With their concept proven, a follow-on agreement was signed with wind farm developers, who will be funding the emplacement of another 2 AN/TPS-77 radars in Northumberland and Yorkshire, as part of their project’s installation cost.
The TPS-77 is a transportable version of the L-Band FPS-117. Like its counterpart, it offers secondary air traffic control capabilities, and can be stationed at fixed sites within radomes. It can also be moved, however, using trucks or even a C-130 Hercules aircraft, if redeployment becomes necessary. The antenna array and electronics shelter are both standard ISO packages. When set up, the TPS-77 works at ranges out to 280 miles and at elevations up to 100,000 feet, providing 360 degree azimuth coverage for 24 hours a day, through weather and clutter, even with no on-site personnel.
