scholarly journals Wind turbine impact on operational weather radar I/Q data: characterisation and filtering

2017 ◽  
Vol 10 (5) ◽  
pp. 1739-1753 ◽  
Author(s):  
Lars Norin
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Negative Impact ◽  
Weather Radar ◽  
Rapid Expansion ◽  
Weather Radars ◽  
Radar Systems ◽  
Increasing Demand ◽  
Yaw Angle ◽  
The Impact

Abstract. For the past 2 decades wind turbines have been growing in number all over the world as a response to the increasing demand for renewable energy. However, the rapid expansion of wind turbines presents a problem for many radar systems, including weather radars. Wind turbines in the line of sight of a weather radar can have a negative impact on the radar's measurements. As weather radars are important instruments for meteorological offices, finding a way for wind turbines and weather radars to co-exist would be of great societal value.Doppler weather radars base their measurements on in-phase and quadrature phase (I/Q) data. In this work a month's worth of recordings of high-resolution I/Q data from an operational Swedish C-band weather radar are presented. The impact of point targets, such as masts and wind turbines, on the I/Q data is analysed and characterised. It is shown that the impact of point targets on single radar pulses, when normalised by amplitude, is manifested as a distinct and highly repeatable signature. The shape of this signature is found to be independent of the size, shape and yaw angle of the wind turbine. It is further demonstrated how the robustness of the point target signature can be used to identify and filter out the impact of wind turbines in the radar's signal processor.

scholarly journals Wind turbine impact on operational weather radar I/Q data: characterisation and filtering

2017 ◽  
Author(s):  
Lars Norin
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Negative Impact ◽  
Weather Radar ◽  
Rapid Expansion ◽  
Weather Radars ◽  
Radar Systems ◽  
Increasing Demand ◽  
Yaw Angle ◽  
The Impact

Abstract. For the past two decades wind turbines have been growing in number all over the world as a response to the increasing demand for renewable energy. However, the rapid expansion of wind turbines presents a problem for many radar systems, including weather radars. Wind turbines in line-of-sight of a weather radar can have a negative impact on the radar's measurements. As weather radars are important instruments for meteorological offices, finding a way for wind turbines and weather radars to co-exist would be of great societal value. Doppler weather radars base their measurements on in-phase and quadrature phase (I/Q) data. In this work a month worth of recordings of high resolution I/Q data from an operational Swedish C-band weather radar are presented. The impact of point targets, such as masts and wind turbines, on the I/Q data is analysed and characterised. It is shown that the impact of point targets on single radar pulses is manifested as a distinct and highly repeatable signature. The shape of this signature is found to be independent of the size, shape, and yaw angle of the wind turbine. It is further demonstrated how the robustness of the point target signature can be used to identify and filter out the impact of wind turbines in the radar's signal processor.

scholarly journals A quantitative analysis of the impact of wind turbines on operational Doppler weather radar data

2015 ◽  
Vol 8 (2) ◽  
pp. 593-609 ◽  
Author(s):  
L. Norin
Keyword(s):  
Quantitative Analysis ◽  
Wind Turbines ◽  
Wind Farm ◽  
Negative Impact ◽  
Weather Radar ◽  
Radar Data ◽  
Doppler Weather Radar ◽  
Spectral Moments ◽  
Using Data ◽  
The Impact

Abstract. In many countries wind turbines are rapidly growing in numbers as the demand for energy from renewable sources increases. The continued deployment of wind turbines can, however, be problematic for many radar systems, which are easily disturbed by turbines located in the radar line of sight. Wind turbines situated in the vicinity of Doppler weather radars can lead to erroneous precipitation estimates as well as to inaccurate wind and turbulence measurements. This paper presents a quantitative analysis of the impact of a wind farm, located in southeastern Sweden, on measurements from a nearby Doppler weather radar. The analysis is based on 6 years of operational radar data. In order to evaluate the impact of the wind farm, average values of all three spectral moments (the radar reflectivity factor, absolute radial velocity, and spectrum width) of the nearby Doppler weather radar were calculated, using data before and after the construction of the wind farm. It is shown that all spectral moments, from a large area at and downrange from the wind farm, were impacted by the wind turbines. It was also found that data from radar cells far above the wind farm (near 3 km altitude) were affected by the wind farm. It is shown that this in part can be explained by detection by the radar sidelobes and by scattering off increased levels of dust and turbulence. In a detailed analysis, using data from a single radar cell, frequency distributions of all spectral moments were used to study the competition between the weather signal and wind turbine clutter. It is shown that, when weather echoes give rise to higher reflectivity values than those of the wind farm, the negative impact of the wind turbines is greatly reduced for all spectral moments.

Detailed Observations of Wind Turbine Clutter with Scanning Weather Radars

2009 ◽  
Vol 26 (5) ◽  
pp. 894-910 ◽  
Author(s):  
B. M. Isom ◽  
R. D. Palmer ◽  
G. S. Secrest ◽  
R. D. Rhoton ◽  
D. Saxion ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Time Series Data ◽  
Wind Farms ◽  
Three Dimensions ◽  
Series Data ◽  
Unique Type ◽  
Weather Radars ◽  
Radar Systems ◽  
Spectral Components ◽  
The Impact

Abstract The wind power industry has seen tremendous growth over the past decade and with it has come the need for clutter mitigation techniques for nearby radar systems. Wind turbines can impart upon these radars a unique type of interference that is not removed with conventional clutter-filtering methods. Time series data from Weather Surveillance Radar-1988 Doppler (WSR-88D) stations near wind farms were collected and spectral analysis was used to investigate the detailed characteristics of wind turbine clutter. Techniques to mask wind turbine clutter were developed that utilize multiquadric interpolation in two and three dimensions and can be applied to both the spectral moments and spectral components. In an effort to improve performance, a nowcasting algorithm was incorporated into the interpolation scheme via a least mean squares criterion. The masking techniques described in this paper will be shown to reduce the impact of wind turbine clutter on weather radar systems at the expense of spatial resolution.

scholarly journals Estimating reflectivity values from wind turbines for analyzing the potential impact on weather radar services

2015 ◽  
Vol 8 (2) ◽  
pp. 1477-1509
Author(s):  
I. Angulo ◽  
O. Grande ◽  
D. Jenn ◽  
D. Guerra ◽  
D. de la Vega
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Wind Farm ◽  
Weather Radar ◽  
Radar Signal ◽  
Weather Radars ◽  
Potential Impact ◽  
Processing Techniques ◽  
Signal Processing Techniques ◽  
Do So

Abstract. The World Meteorological Organization (WMO) has repeatedly expressed concern over the increasing number of impact cases of wind turbine farms on weather radars. Since nowadays signal processing techniques to mitigate Wind Turbine Clutter (WTC) are scarce, the most practical approach to this issue is the assessment of the potential interference from a wind farm before it is installed. To do so, and in order to obtain a WTC reflectivity model, it is crucial to estimate the Radar Cross Section (RCS) of the wind turbines to be built, which represents the power percentage of the radar signal that is backscattered to the radar receiver. This paper first characterizes the RCS of wind turbines in the weather radar frequency bands by means of computer simulations based on the Physical Optics theory, and then proposes a simplified model to estimate wind turbine RCS values. This model is of great help in the evaluation of the potential impact of a certain wind farm on the weather radar operation.

scholarly journals A Spectral Model of Grid Frequency for Assessing the Impact of Inertia Response on Wind Turbine Dynamics

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2492
Author(s):  
Feng Guo ◽  
David Schlipf
Keyword(s):  
Renewable Energy ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Negative Impact ◽  
Linear Time ◽  
Notch Filter ◽  
Rate Of Change ◽  
Spectral Model ◽  
The Impact ◽  
Inertia Response

The recent developments in renewable energy have led to a higher proportion of converter-connected power generation sources in the grid. Operating a high renewable energy penetration power system and ensuring the frequency stability could be challenging due to the reduced system inertia, which is usually provided by the conventional synchronous generators. Previous studies have shown the potential of wind turbines to provide an inertia response to the grid based on the measured rate of change of the grid frequency. This is achieved by controlling the kinetic energy extraction from the rotating parts by its converters. In this paper, we derive a spectral-based model of the grid frequency by analyzing historical measurements. The spectral model is then used to generate realistic, generic, and stochastic signals of the grid frequency for typical aero-elastic simulations of wind turbines. The spectral model enables the direct assessment of the additional impact of the inertia response control on wind turbines: the spectra of wind turbine output signals such as generator speed, tower base bending moment, and shaft torsional moment are calculated directly from the developed spectral model of the grid frequency and a commonly used spectral model of the turbulent wind. The calculation of output spectra is verified with non-linear time-domain simulations and spectral estimation. Based on this analysis, a notch filter is designed to significantly alleviate the negative impact on wind turbine’s structural loads due to the inertia response with only a small reduction on the grid support.

scholarly journals A quantitative analysis of the impact of wind turbines on operational Doppler weather radar data

2014 ◽  
Vol 7 (8) ◽  
pp. 8743-8776
Author(s):  
L. Norin
Keyword(s):  
Quantitative Analysis ◽  
Wind Turbines ◽  
Wind Farm ◽  
Negative Impact ◽  
Weather Radar ◽  
Radar Data ◽  
Doppler Weather Radar ◽  
Spectral Moments ◽  
Using Data ◽  
The Impact

Abstract. In many countries wind turbines are rapidly growing in numbers as the demand for energy from renewable sources increases. The continued deployment of wind turbines can, however, be problematic for many radar systems, which are easily disturbed by turbines located in radar line-of-sight. Wind turbines situated in the vicinity of Doppler weather radars can lead to erroneous precipitation estimates as well as to inaccurate wind- and turbulence measurements. This paper presents a quantitative analysis of the impact of a wind farm, located in southeastern Sweden, on measurements from a nearby Doppler weather radar. The analysis is based on six years of operational radar data. In order to evaluate the impact of the wind farm, average values of all three spectral moments (the radar reflectivity factor, absolute radial velocity, and spectrum width) of the nearby Doppler weather radar were calculated, using data before and after the construction of the wind farm. It is shown that all spectral moments, from a large area at and downrange from the wind farm, were impacted by the wind turbines. It was also found that data from radar cells far above the wind farm (near 3 km altitude) were affected by the wind farm. We show that this is partly explained by changes in the atmospheric refractive index, bending the radar beams closer to the ground. In a detailed analysis, using data from a single radar cell, frequency distributions of all spectral moments were used to study the competition between the weather signal and wind turbine clutter. We show that when weather echoes give rise to higher reflectivity values than that of the wind farm, the negative impact of the wind turbines disappears for all spectral moments.

An Operation Data-Based Method for the Diagnosis of Zero-Point Shift of Wind Turbines Yaw Angle

2019 ◽  
Vol 142 (2) ◽  
Author(s):  
Davide Astolfi ◽  
Francesco Castellani ◽  
Ludovico Terzi
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Wind Farm ◽  
Negative Impact ◽  
Zero Point ◽  
Test Case ◽  
Case Discussion ◽  
Angle Shift ◽  
Points Of View ◽  
Yaw Angle

Abstract The alignment of the wind turbine yaw to the wind direction is an important topic for wind turbine technology by several points of view. For example, the negative impact on power production of an undesired non-optimal yaw alignment can be impressive. The diagnosis of zero-point shifting of the yaw angle is commonly performed by adopting supplementary measurement sources, as for example, light detection and ranging (LIDAR) anemometers. The drawback is that these measurement campaigns have a certain cost against an uncertain diagnosis outcome. There is therefore an increasing interest from wind turbine practitioners in the formulation of zero-point yaw angle shift diagnosis techniques through the use of nacelle anemometer data. This work is devoted to this task and is organized as a test case discussion: a wind farm featuring six multi-megawatt wind turbines is considered. The study of the power factor Cp as function of the yaw error (estimated through nacelle anemometer data) is addressed. The proposed method has been validated through the detection of a 8 deg zero-point shift of the yaw angle of one wind turbine in the test case wind farm. After the correction of this offset, the performance of the wind turbine of interest is shown to be comparable with the nominal. The results of this work therefore support that an appropriate analysis of nacelle anemometer and operation data can be effective for the diagnosis of zero-point shift of the yaw angle of wind turbines.

scholarly journals Estimating reflectivity values from wind turbines for analyzing the potential impact on weather radar services

2015 ◽  
Vol 8 (5) ◽  
pp. 2183-2193 ◽  
Author(s):  
I. Angulo ◽  
O. Grande ◽  
D. Jenn ◽  
D. Guerra ◽  
D. de la Vega
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Wind Farm ◽  
Weather Radar ◽  
Radar Signal ◽  
Weather Radars ◽  
Proposed Model ◽  
Potential Impact ◽  
Processing Techniques ◽  
Signal Processing Techniques

Abstract. The World Meteorological Organization (WMO) has repeatedly expressed concern over the increasing number of impact cases of wind turbine farms on weather radars. Current signal processing techniques to mitigate wind turbine clutter (WTC) are scarce, so the most practical approach to this issue is the assessment of the potential interference from a wind farm before it is installed. To do so, and in order to obtain a WTC reflectivity model, it is crucial to estimate the radar cross section (RCS) of the wind turbines to be built, which represents the power percentage of the radar signal that is backscattered to the radar receiver. For the proposed model, a representative scenario has been chosen in which both the weather radar and the wind farm are placed on clear areas; i.e., wind turbines are supposed to be illuminated only by the lowest elevation angles of the radar beam. This paper first characterizes the RCS of wind turbines in the weather radar frequency bands by means of computer simulations based on the physical optics theory and then proposes a simplified model to estimate wind turbine RCS values. This model is of great help in the evaluation of the potential impact of a certain wind farm on the weather radar operation.

scholarly journals Tourist Viewshed Externalities and Wind Energy Production

2017 ◽  
Vol 46 (2) ◽  
pp. 224-241 ◽  
Author(s):  
Jacob R. Fooks ◽  
Kent D. Messer ◽  
Joshua M. Duke ◽  
Janet B. Johnson ◽  
Tongzhe Li ◽  
...  
Keyword(s):  
Wind Energy ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Energy Production ◽  
Hotel Room ◽  
Negative Effect ◽  
The Impact ◽  
Large Wind

This study uses an experiment where ferry passengers are sold hotel room “views” to evaluate the impact of wind turbines views on tourists’ vacation experience. Participants purchase a chance for a weekend hotel stay. Information about the hotel rooms was limited to the quality of the hotel and its distance from a large wind turbine, as well as whether or not a particular room would have a view of the turbine. While there was generally a negative effect of turbine views, this did not hold across all participants, and did not seem to be effected by distance or hotel quality.

Microstrip antenna array with an inclined surface and an increased distance between patches

2021 ◽  
Author(s):  
A.R. Bestugin ◽  
M.B. Ryzhikov ◽  
Yu.A. Novikova ◽  
I.A. Kirshina
Keyword(s):  
Antenna Array ◽  
Mutual Influence ◽  
Weather Radar ◽  
Main Beam ◽  
Weather Radars ◽  
Weather Events ◽  
A New Technique ◽  
The Impact ◽  
Inclined Surface ◽  
Inclined Beam

A new technique for designing a path antenna array with an inclined beam is proposed. It boils down to finding a certain combination of parameters that use the secondary main maxima of the diagram as the main beam and at the same time guarantee the greatest distance between the emitters that does not yet lead to the occurrence of secondary main maxima in the antenna radiation pattern. This simplifies the geometric structure of the antenna, reduces its cost, simplifies the microstrip power system, and reduces the mutual influence of individual elements in the antenna array. To combine the possibility of reducing the radio visibility of the antenna by changing the orientation of the antenna opening while maintaining its emissivity in a given viewing plane, it is possible to implement an antenna with a main beam deviated from the normal. The efficiency of reducing backscattering for the radar range due to the tilt of the antenna outside the operating frequency band of the antenna is investigated. Thus, when mechanically scanning the antenna, due to the fact that the main beam of the antenna array is deviated from the normal, it is possible to achieve a significant reduction in the average backscattering pattern of at least 25 dB. It is known that improving the safety of small aircraft at low altitudes, as well as on take-off and landing sites, is directly related to the introduction of a small weather radar, which warns of the presence of dangerous phenomena along the flight path: thunderstorms, turbulence, and wind. When the onboard radar is operating in thunderstorm or turbulence detection modes, the presence of re-reflections from the Earth's surface can lead to the formation of false areas that are dangerous for flight. You can reduce the likelihood of such false zones by spatial filtering of interference from the ground using antennas with a low level of side lobes in the lower hemisphere. The relevance of the problem of reducing the influence of interference from the ground on the correctness of the wind speed estimation in the weather radar is confirmed by publications. They are focused on filtering interference from the earth's surface in the frequency domain for ground-based weather radars or for airborne radars, but by the main beam of the alignment diagram and the rule of its elevation to avoid touching the ground. The second part of the research is devoted to reducing the influence of re-reflections from the earth on the probability of forming false areas of dangerous weather events in the weather radar. To reduce the impact of interference, it is proposed to install an antenna with an upward tilt.

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