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RF-Emissions from Wind Energy Plants An Example

RF-Emissions from Wind Energy Plants An Example. Secondary and Primary Emission. What do you see?. the sun, right the moon, well... ...but: you see the sun, folded by the moon. What do you see?. the moon, well...

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RF-Emissions from Wind Energy Plants An Example

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  1. RF-Emissions from Wind Energy PlantsAn Example Secondary and Primary Emission

  2. What do you see? • the sun, right • the moon, well... ...but: you see the sun, folded by the moon Secondary RF Emissions from Wind Energy Plants Karl Grypstra, MPIfR

  3. What do you see? the moon, well... ... but, you see the sun, folded by the moon, folded by the earth You know, what you see, ... and you see what you know Secondary RF Emissions from Wind Energy Plants Karl Grypstra, MPIfR

  4. The Microwave Case Example: Point – to – Point Microwave Link in C-Band Energy Reflected by Wind Mills Secondary RF Emissions from Wind Energy Plants Karl Grypstra, MPIfR

  5. The undisturbed signal Microwave link in C-Band • spectrum • waterfall plot Secondary RF Emissions from Wind Energy Plants Karl Grypstra, MPIfR

  6. The scene I Microwave link between Airport and remote short wave transmitter station distance: ~ 35 km Secondary RF Emissions from Wind Energy Plants Karl Grypstra, MPIfR

  7. The scene II Transmitter antenna C-Band (~ 4 GHz) 2 m parabolic dish -3 dB beam with of transmitting antenna: 2 x 1.3° =2.6 ° that means, 50% of energy is transmitted inside this cone, but also 50 % outside. Secondary RF Emissions from Wind Energy Plants Karl Grypstra, MPIfR

  8. The scene III • yellow lines: -10 dB beam with (10 % of the transmitted energy ist distributed outside this cone) • yellow circle and picture: wind energy park Secondary RF Emissions from Wind Energy Plants Karl Grypstra, MPIfR

  9. Wind Farm Weilerswist 10 x Enercon E53/800 • diameter: 53 m • Hub height: 74 m • min. speed: 12 rpm (36 blades per Minute) • max. speed: 29 rpm (117 Blades per Minute) • output voltage: 400 volts • max. electrical output power: 800 kW • power control: pitch • supplied population by this windfarm: 7300 habitants Secondary RF Emissions from Wind Energy Plants Karl Grypstra, MPIfR

  10. The Scene IV • Distance between transmitter and wind plant: min. 7,6 km; max. 8,7 km • Distance between wind park and receiving antenna: min. 3,3 km; max. 4,2 km angle between main lobe and wind park: ~ 30 degrees Secondary RF Emissions from Wind Energy Plants Karl Grypstra, MPIfR

  11. The scene V • Wind mills seen from my house • closer view Secondary RF Emissions from Wind Energy Plants Karl Grypstra, MPIfR

  12. C-Band-Receiver • Standard Gain Horn w Waveguide (BP-Filter) • Preamplifier (Gain ~25dB, NF < 3 dB) • Spectrum Analyzer Aaronia HF-60105 (with Software) Secondary RF Emissions from Wind Energy Plants Karl Grypstra, MPIfR

  13. Detection of reflected energyfrom a single wind turbine spectrum analyzer de facto in time domain mode 2,93 s per sweep at virtually zero span 1,2 s beween 2 blades,  3,6 s per turn  17 turns per minute rotational speed is variable, following wind speed Secondary RF Emissions from Wind Energy Plants Karl Grypstra, MPIfR

  14. Example @ virtually no wind • wind calm ( @ 10.01.2010 22:45 hour) sweep time: 23 s/Trace wind speed at the last 24 hours (recorded ~ 2 km away from the wind park) Secondary RF Emissions from Wind Energy Plants Karl Grypstra, MPIfR

  15. 1st Example @ heavy wind • 16.01.2010 10:19-11:19 hour • received RF power varies @ about 10 dB • total RF power plot during the last 24 hr Secondary RF Emissions from Wind Energy Plants Karl Grypstra, MPIfR

  16. 2nd example @ heavy wind • short time fluctuations of RF-Power • long time fluctuations of RF-Power (last 24 hours) • Wind speed, measured by an anemometer approx. 2 km away from wind farm (last 24 hours) Secondary RF Emissions from Wind Energy Plants Karl Grypstra, MPIfR

  17. mutual coupling • Echos from the wind mills with high dynamic and sometimes very distinct time behaviour • mutual coupling between some of the 30 blades and radar crossing section: 5000 square meters (EADS) 35 dBm^2 (Eurocontrol) Secondary RF Emissions from Wind Energy Plants Karl Grypstra, MPIfR

  18. Transmitter is switched off • this frequency is „clean“ since the end of January 2010 24 hour plot Secondary RF Emissions from Wind Energy Plants Karl Grypstra, MPIfR

  19. Trends I Past&Present • Past: Dense Microwave Link Infrastructure • Present: Decline of earthboundcommunication grids in L-, C- and X-Band Secondary RF Emissions from Wind Energy Plants Karl Grypstra, MPIfR

  20. Trends II Present&Future • Feeders in the K- and Q-Band • mobile com antennas (pico- and femtocells) • handsets (UHF, L-, S-, C-Band) with frequency agility MIMO structures • WLAN @ 2,695 and 5,7 GHz • HAPS (high altitude power stations) • Satellite radio stations • LEO´s (low orbiting satellites), partly with beam steering Secondary RF Emissions from Wind Energy Plants Karl Grypstra, MPIfR

  21. Trends III • (LEO´s, MEO´s and) geostationary satellites • sometimes beacons in the X- and K-Band Downstreams in the L-,C-, X-, K- and Ka-Band • seen from „pole position“ by courtesy of Fraunhofer FHR, Wachtberg Secondary RF Emissions from Wind Energy Plants Karl Grypstra, MPIfR

  22. Optical and RF „Picture“ Secondary RF Emissions from Wind Energy Plants Karl Grypstra, MPIfR

  23. Search for primary emission@ Distance ~ 200 m • Frequency range 1,25-1,40 GHz Out of band rejection @ GSM bands: > 100 dB NF 4,1 dB • On-Source / Off-Source-Measurement (Antenna AZM= 90° turned) • Reduction of raw-Data with Program „Audacity“ works as digital oscilloscope, FFT-Analyzer or autocorrelation spectrometer, with high dynamic range Secondary RF Emissions from Wind Energy Plants Karl Grypstra, MPIfR

  24. L-Band Receiver • Helical Antenna LHC n=20 • BP Filter 1,25-1,4 GHz • Amplifier G ~30 dB • BP-Filter 1,25-1,4 GHz • Amplifier G ~20 dB • Back-Diode Detector • Video-Amp. G ~30 dB • MP3-Player as 16 bit D/A-Converter, fSample = 33,2 kHz, Program „Audacity“ Secondary RF Emissions from Wind Energy Plants Karl Grypstra, MPIfR

  25. First results Wind Turbine (on and off source) Electric fence and RADAR Noise from the city Motorcycle Secondary RF Emissions from Wind Energy Plants Karl Grypstra, MPIfR

  26. Conclusion: • Remarkable Secondary Emissions „Pulsar–like“ scattering • Less Primary Emissions detected • Further investigations at different types of wind generators are needed  Emissions critical for radio astronomy Secondary RF Emissions from Wind Energy Plants Karl Grypstra, MPIfR

  27. Thanks for your attention Secondary RF Emissions from Wind Energy Plants Karl Grypstra, MPIfR

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