Five microphones and associated Syncboards (GPS synched data acquisition units) were placed over a range of 100 to 400 m from Wind Turbine #4 at Flø in Denmark.
In addition to logging turbine noise using GRAS 7 mm microphones, a flare gun was used to demonstrate the synchronization capabilities of the autonomous GPS Synchronized Sync Boards. A total of ten GBytes of data including turbine noise, background noise, and synthetic test signals, were logged by the five boards. In addition separate instrumentation systems logged the turbine and metrological parameters along with standardized acoustic measurements.
In the screen shot below, the upper graph shows 10 minutes of acoustic data with the four flare gun shots in the middle. Each shot consist of two detonations, the actual firing of the flare out of the gun, and then the subsequent explosion of the flare some 50 m up in the air.
The zoomed large middle graph has a 50 s long x axis and shows all four shots. The five plots from bottom to top cover distances from about 100 to 400 m from the turbine. The time offsets are due to the sound propagation delay.
The screen shot below shows the first shot in greater detail with a 2 second x axis on the middle graph.
Finally, a synthetized 4 kHz tone generated by a loudspeaker at the base of the turbine is clearly seen in the FFT Spectrum (50,000 point transform) in the bottom plot in the screen shot below. This is measured at a distance of 400 m from the turbine.
(The vertical scale is uncalibrated).
Looking at the waveform plot above the spectrum the tone is clearly buried in noise, but the high resolution FFT transform is able to dig it out of the noise.
The data obtained in this test on June 19, 2016 clearly demonstrates the capabilities of the stand alone data acquisition units (Sync Boards)
It is our goal, outside the scope of this EUDP sponsored research project, to perform data mining and analysis on these data sets to see if new insights can be obtained.
The nanosync demonstration board has been tested:
- Against existing off-the-shelf precision synchronized systems provided by CIM A/S and has shown excellent absolute time alignment.
- Successfully operated on an operating the Nord Tank 500 test turbine blade at the DTU Department of Wind Energy in Risø, Denmark.
- And validated the synchronization capabilities in practical (potato) field measurements using five microphones as seen above.
The demonstration Syncboard has shown that it opens up a new range of possibilities thanks to its small size (smart phone size), high quality battery-operated instrumentation, which potentially can be produced at low cost compared to existing solutions. It has shown that it can open research opportunities in wind power as well as other energy related industries. In addition, it has a broad range of applications outside wind and energy, and if brought to market as a commercial product sees a significant opportunity for high volume which can help drive down the price.
This experiments marks the conclusion of this EUDP sponsored project. It is our goal to continue to spread the news of the successful implementation after the end of the project since it clearly demonstrates a price performance breakthrough in high performance instrumentation systems, as well as opening new platforms for innovation.
As a demonstration project, it is our hope that our efforts will contribute to finding partners who will carry this concept further to fully commercialized products. Our are welcome to contact DELTA or our other partners to discussion future cooperation in terms of commercialization or additional research projects.
Our thanks to EUDP and the research partners
- DTU Wind Energy
- GRAS A/S
- CIM A/S
- Siemens Wind Power
Carsten Thomsen, Senior Specialist, Project Manager, DELTA
1 July 2016