North Hoyle Windfarm Report
6 MCA Radar trials 6.13 Mobile radar at higher location The mobile radar was then taken close to the BHP Billiton radar site at Gwaenysgor. At this site it was approximately 200 metres above sea level and 5.2 nm from the wind farm. In Figure 6-24 it can be seen that the detection of small targets was not greatly improved but the discrimination of the western meteorology mast from turbine 26 and the service vessel immediately south of turbine 6 was apparent. Figure 6-24: Mobile radar at Gwaenysgor The radar recording unit was then transferred to the BHP Billiton Raytheon radar unit, close by. The position of this radar relative to the wind farm is shown in Figure 6-25. The displayed sizes of the North Hoyle WTGs from Gwaenysgor appear significantly greater than theoretical calculated size, the across range echo size being around 610 metres at a range of 5.2 nm and the down range depth being around 200 metres. For ARPA or VTS / Port radar tracking systems the effects may be that tracking vessels within or close to wind farms may be problematic . This was found to be the case with the "Norbay" ARPA systems and with the BHP Billiton tracking system at Gwaenysgor. The raw radar image with high persistence level is shown in Figure 6-26. Using a high persistence level the recorded data would, when filtered, detect targets if not directly behind turbines. This is illustrated in Figure 6-27. When target vessel to the North of the wind farm was clear by approximately 1500 metres, its response was increased noticeably, as is shown in Figure 6-28. Figure 6-25: Relative Position of BHP Billiton Raytheon radar head at Gwaenysgor Figure 6-26: Raw radar with high persistence level Figure 6-27: Filtered display - high persistence Figure 6-28: Target lifeboats clear of the wind farm
|
