Transcript Document

Netherlands Institute for Radio Astronomy
Wind turbines and LOFAR
Hans van der Marel
ASTRON
Wind Turbine meeting, Chalmers
ASTRON is part of the Netherlands Organisation for Scientific Research (NWO)
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LOFAR
 Low Frequency Array
 10 - 90 MHz (LBA)
 110 - 250 MHz (HBA)
 Arranged in stations
 Station connected with
fibres
 Station correlation
 Central correlator
(Groningen)
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LOFAR locations
 Core
 Remote
stations
 International
stations
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LOFAR core and environment
 Large receiving
surface
 Short baselines
 Susceptible to
interference
 Radio quiet zone
coordination zone
of ~ 6 km
Wind turbines!
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Wind turbines in Drenthe
 Up to 200 MW in 2020
 At least 3 MW per wind turbine
 Clusters of at least 5 wind turbines
 No wind turbines in LOFAR zone 1 (radio quiet zone)
 Only wind turbines in LOFAR zone 2 (coordination zone) if
they do not impede the LOFAR project
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Windfarm ‘Hondtocht’
 LOFAR monitoring survey in October 2006
 Local authority:
Dronten (Flevoland)
 Wind turbine: Vestas - V66 - 1,75 MW
 Number of wind turbines:
8
 Installed capacity:
14,75 MW
 Rotor axis height:
67 metres
 Rotor diameter:
66 metres
 Measurements by:
Mark Bentum and Harm-Jan Stiepel
 Processing by:
Rob Millenaar and Albert-Jan Boonstra
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Measurement set-up
 R&S ESMB monitoring receiver
(9 kHz - 3 GHz)
 R&S HE010 active antenna
(9 kHz - 80 MHz)
 VULP 9118G passive antenna
(35 - 1500 MHz)
 Miteq 10 - 1000 MHz amplifier
(18 dB)
 Rotors for azimuth and
polarisation
 (R&S FSP spectrum analyzer
(9 kHz - 3 GHz))
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Measurements
 Scatter measurements of FM transmitters
 Spectrum measurements wind turbine ON / OFF
 5 - 80 MHz
 30 - 1000 MHz
 ‘Standard’ LOFAR monitoring measurements
 Spectrum analyzer measurements
 Amplitude
 Emission
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Spectrum Measurements (1)
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Spectrum measurements (2)
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Amplitude measurements on FM
transmitter frequency
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Emission measurements (inside wind
turbine near electronics cabinet)
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Emission measurements (2)
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Emission measurements (3)
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Conclusions
 Electronics is potential source of emission
 Partly shielded by wind turbine structure
 Might be different for other wind turbines
 Amplitude modulation due to variable reflections
 For LOFAR frequencies AM on already distorted channels
due to dispersion
More investigations needed:
 Emission and reflections of bigger wind turbines and other
types
 Dispersion and reflections at higher frequencies
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