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Wind farm meeting 27 April 2010, Goteborg (SE) Measurements of primary radiation at a wind farm close to the Sardinia Radio Telescope R. Ambrosini (IRA),

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Presentation on theme: "Wind farm meeting 27 April 2010, Goteborg (SE) Measurements of primary radiation at a wind farm close to the Sardinia Radio Telescope R. Ambrosini (IRA),"— Presentation transcript:

1 Wind farm meeting 27 April 2010, Goteborg (SE) Measurements of primary radiation at a wind farm close to the Sardinia Radio Telescope R. Ambrosini (IRA), P. Bolli (OAC), C. Bortolotti (IRA), F. Gaudiomonte (OAC), F. Messina (OAC), M. Roma (IRA) Osservatorio Astronomico di CagliariIstituto di Radioastronomia Sezione di Medicina

2 2/21 P. Bolli, Measurements of primary radiation at a wind farm close to SRT Wind farm meeting 27 April 2010, Goteborg (SE) Agenda The Sardinia Radio Telescope; The RFI mobile station at SRT; Characteristics of the wind farm under test; Measurements: Spectrum in P, L and S bands from power station and from each single turbine; Wide and narrow band emission; Dependence of the RFI intensity vs the distance.

3 3/21 P. Bolli, Measurements of primary radiation at a wind farm close to SRT Wind farm meeting 27 April 2010, Goteborg (SE) Fully steerable radio telescope for: Radio astronomy, Geodynamical studies, Deep Space Network, Single dish and VLBI 0.3-100 GHz continuous frequency coverage 64 m diameter primary mirror; 7.9 m diameter secondary mirror Gregorian configuration with Shaped Surfaces Active Surface: Primary mirror with 1116 actuators a) Compensate gravitational and thermal deformations b) Convert Shaped surface of the primary to a Parabolic surface for primary focus operation Six focal positions (up to 20 receivers): Primary, Gregorian, Four Beam Wave Guide Primary surface accuracy: 150 um RMS Pointing accuracy (RMS): 2 ÷ 5 arcsec SRT Technical Specifications

4 4/21 P. Bolli, Measurements of primary radiation at a wind farm close to SRT Wind farm meeting 27 April 2010, Goteborg (SE) Features of SRT site The SRT site is located 35 Km North of Cagliari (700 m asl). Latitude: 39d 29m 50s N Longitude: 9d 14m 40s E 1.The site is well shielded by mountains around the radio telescope. 2.The area is far away from populated centers (small villages at > than 5 Km).

5 5/21 P. Bolli, Measurements of primary radiation at a wind farm close to SRT Wind farm meeting 27 April 2010, Goteborg (SE) Wind farm close to SRT

6 6/21 P. Bolli, Measurements of primary radiation at a wind farm close to SRT Wind farm meeting 27 April 2010, Goteborg (SE) SRT Mobile RFI station

7 7/21 P. Bolli, Measurements of primary radiation at a wind farm close to SRT Wind farm meeting 27 April 2010, Goteborg (SE) FeaturesMobile station of SRT VanMercedes Sprinter 315 CDI Maximum seats2 Max frequency18 GHz (Normal operation); 40 GHz Antennas1 LPDA (0.3 – 0.6 GHz); 1 LPDA (0.1 – 1.3 GHz); 1 dual ridge horn (1 – 18 GHz); 1 dual ridge horn (18 – 40 GHz) Telescope pole height11 m Telescope movementUp/down servo; Azimuth servo or manual; Polarization servo Spectrum analyzerPSA 4446 E (up to 44 GHz) Characteristics BandFrequency bandAntenna gainChain gainNoise figure P290 – 428 MHz9 dBi36.2 dB3.8 dB L1.17 – 1.84 GHz7 dBi29.8 dB4 dB S1.99 – 3.37 GHz7.8 dBi25 dB5.3 dB S / C2.98 – 5.81 GHz12 dBi25 dB5.5 dB C / X5.22 – 9.25 GHz11.5 dBiTBD X / Ku7.76 – 18 GHz12.5 dBiTBD K / Ka18 – 40 GHzTBD

8 8/21 P. Bolli, Measurements of primary radiation at a wind farm close to SRT Wind farm meeting 27 April 2010, Goteborg (SE) Effects produced by wind farm Primary radiation Secondary radiation Instability of background Microwave link for telemetry and remote control; Emissions from generators and transformers; Sparks and corona from power lines and insulators; Reflection of radio links; Modulation of the near field background signal of the antenna by its periodically varying electrical characteristic

9 9/21 P. Bolli, Measurements of primary radiation at a wind farm close to SRT Wind farm meeting 27 April 2010, Goteborg (SE) Characteristics of the wind farm Modell of turbineVESTAS V-52 Number of turbins26 Electrical power (maximum)22 Mwatt (850 Kwatt each) Operational data50 Hz/60 Hz - 690 V Dimension of each turbineHeight of the metallic mast 55 m, 3 resin blades with radius 26 m Blade rotation velocity14 - 31.4 rpm (average 26 rpm)

10 10/21 P. Bolli, Measurements of primary radiation at a wind farm close to SRT Wind farm meeting 27 April 2010, Goteborg (SE) Electrical scheme

11 11/21 P. Bolli, Measurements of primary radiation at a wind farm close to SRT Wind farm meeting 27 April 2010, Goteborg (SE) RFI campaigns SessionDateWeatherMonitored bandsTarget 119 Jan 2010Sunny dayP and LGeneral overview 220 Jan 2010Rainy dayP and LPower station 311 Feb 2010Sunny dayP, L, and SPower station and single turbine

12 12/21 P. Bolli, Measurements of primary radiation at a wind farm close to SRT Wind farm meeting 27 April 2010, Goteborg (SE) Survey at the wind farm AZC 40° Distance @ 3.5 Km; session #3

13 13/21 P. Bolli, Measurements of primary radiation at a wind farm close to SRT Wind farm meeting 27 April 2010, Goteborg (SE) Pointing measurement Pol. VPol. H AZC 40° yellow AZC 40°+90° blue AZC 40°-90° purple -62.6 dBm

14 14/21 P. Bolli, Measurements of primary radiation at a wind farm close to SRT Wind farm meeting 27 April 2010, Goteborg (SE) Wide-band measurement Max holdSingle view Blue : Pol. V Yellow: Pol. H Distance @ 500 m; session #3

15 15/21 P. Bolli, Measurements of primary radiation at a wind farm close to SRT Wind farm meeting 27 April 2010, Goteborg (SE) Zero-span measurement Distance @ 1 Km; session #3

16 16/21 P. Bolli, Measurements of primary radiation at a wind farm close to SRT Wind farm meeting 27 April 2010, Goteborg (SE) Emission in P-band 20 Jan. (rainy)19 Jan. (sunny) Distance @ 3.5 Km; session #1,2

17 17/21 P. Bolli, Measurements of primary radiation at a wind farm close to SRT Wind farm meeting 27 April 2010, Goteborg (SE) n. 9 @ 7 Km Emission at large distance

18 18/21 P. Bolli, Measurements of primary radiation at a wind farm close to SRT Wind farm meeting 27 April 2010, Goteborg (SE) RFI campaign at a wind farm Power intensity drops in line-of-sight at -100 dBm at 85 Km!

19 19/21 P. Bolli, Measurements of primary radiation at a wind farm close to SRT Wind farm meeting 27 April 2010, Goteborg (SE) Monitoring in L and S bands Below the sensitivity? 21 cm lineS band Distance @ 1 Km; session #3

20 20/21 P. Bolli, Measurements of primary radiation at a wind farm close to SRT Wind farm meeting 27 April 2010, Goteborg (SE) Other notes Narrow band analysis in P and L- band (to monitor intentional control signal) did not show any signals coming from the wind park…. We didnt measure wide-band emission from the single turbine….. …..with the sensitivity of our RF equipment!

21 21/21 P. Bolli, Measurements of primary radiation at a wind farm close to SRT Wind farm meeting 27 April 2010, Goteborg (SE) Conclusions Very high power wide band RFIs coming from power station have been received (especially in P-band, but also in L-band). Those effects are probably due to sparks phenomena which are worst in dry condition. The spectral distribution and the polarization of the RFI emission are variable (depending on the position); More accurate measurements of emission from single turbine and investigations of secondary effects are planned.


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