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Delegates are invited to meet and discuss with the poster presenters during the poster presentation sessions between 10:30-11:30 and 16:00-17:00 on Thursday, 19 November 2015.

Lead Session Chair:
Stephan Barth, ForWind - Center for Wind Energy Research, Germany
Shumpei Kameyama Mitsubishi Electric Corporation, Japan
Co-authors:
Nobuki Kotake (1) F Masaharu Imaki (1) Shumpei Kameyama (1)
(1) Mitsubishi Electric Corporation, Kamakura, Japan

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Poster

Poster Download poster (9.03 MB)

Abstract

Demonstration of the high-availability wind lidar system adapting to atmospheric environment for reliable wind resource assessment

Introduction

The efficient wind resource assessment needs (a)cost-effective measurement, (b)many wind information(ex. vertical profiles) (c)stable data obtaining, and so on. Recently, for realizing above needs, the wind lidar is expected to apply to the wind resource assessment. However, conventional wind lidar systems have an issue in the instability of performance, since signal-to-noise ratio (SNR) related to measurable range depends on the atmospheric condition such as the aerosol density, turbulence, and so forth. To overcome this issue, we developed the the wind lidar system with the adapting parameters to various atmospheric conditions, which automatically realize the best performance under the given atmospheric condition for obtaining high data availability. Here, we demonstrate the above mentioned functions, and its advantageous effects of new product.


Approach

In the previous wind lidar system, the constant parameters, for example, (1) laser beam focusing distance and (2) number of accumulation of received signal that can contribute improving the measurable range, are used for each observation. Therefore, the data availablity of lidar is severely influenced by the atmospheric condition, for example, in the case of low aerosol density (low backscatter coefficient). On the other hand, in this new system, the signal processor derives the best parameters of (1),(2) automatically using obtained range profile of SNR user’s request. This improves the performance of lidar, especially for the data avilavility which offers an advantage to the wind resource assessment.

Main body of abstract

We developed the new vertical wind profiling lidar (velocity azimuth display (VAD) lidar) which has the concept of this automatic adapting parameters to atmospheric conditions. To realize this concept, we newly developed (1) the optics of which the laser beam focusing distance can be optimized automatically, and (2) the signal processor which optimizes the measurement time interval by changing the number of accumulation. The lidar is the pulsed type and its nominal measurable height is 250m with a height resolution of 20m. The measurement time interval can be changed from about 1s to longer time. The laser beam focusing distance can be tuned from a few tens of meters to infinity. The signal processor analizes the range (hight) dependence of SNR and automatically tunes these parameters. We performed the evaluation of this lidar in the actual wind sensing, and compared the height dependence of data availavility "before" and "after" the automatic adapting parameters. We confirmed that there was a distinct effect in data availability especially at the high altitude.

Conclusion

We demonstrated a new concept of wind lidar system with automatic adapting parameters. This functions provide the lidar performance which fits best to the user’s needs under various atmospheric conditions. Especially, this function is very powerful to keep high data availability even in severe atmospheric conditions for lidar (for example, low aerosol density conditions). Therefore, It could contribute the stable measurement for wind resource assessment.



Learning objectives
Since our work contributes to the better wind sensing diveices, the wind farm developpers and consultant companies, who need better tool for wind resource assessment, can have benefits for participation in this conference.