Capacitive sensors for offshore scour monitoring

Abstract

One of the main challenges in the design and operation of offshore wind turbines arises from the uncertainty about maximum scour depth around their foundations. Scour action can lead to excessive excavation of the surrounding seabed and is being considered as a major risk for offshore wind farm developments. An ability to gather information concerning the evolution of scouring will enable the validation of models derived from laboratory-based studies, the assessment of different engineering designs and the development of improved scour countermeasure techniques. However, real-time scour data are not being collected due to a lack of available instrumentation techniques. This paper proposes a new scour monitoring technology for offshore wind turbine installations. The monitoring system consists of arrays of small capacitive scour probes installed around the foundation structure and linked to a wireless network to enable remote data acquisition. Based on this research, it is concluded that the sensor is capable of exhibiting high sensitivity to scour and sediment deposition processes for common sea floor mediums under different temperature conditions in saline water. The proposed monitoring system has considerable potential for field applications that will contribute to improving the resilience and sustainability of offshore structures

A survey of health monitoring systems for wind turbines

“…Michalis et al [80] proposed a similar solution, but with no moving parts. A probe with sensors distributed along its length is embedded into the seabed.…”

Wireless monitoring of scour and re-deposited sediment evolution at bridge foundations based on soil electromagnetic properties

“…The response of the ADR probe and the calibration curve scaling the electrical signal to Preliminary experiments revealed temperature and salinity effects on the signals of a sensor that was embedded into various sediment types [24,25]. Consequently, another set of 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 The temperature influence on the response of the submerged sensor was also evaluated and …”

Visible Light Communication System for Offshore Wind Turbine Foundation Scour Early Warning Monitoring

“…Furthermore, a study applied 3D computational fluid dynamics (CFD) to develop a numerical model to examine the seabed boundary-layer flow around monopile and hexagonal gravity-based foundations of offshore wind turbines; the flow was examined to determine the formation of horseshoe vortices and flow structures to estimate potential scour for engineering designs. The results showed that the horseshoe vortex size for the hexagonal gravity-based foundation was smaller than that for the monopile foundation [26][27][28][29][30]. Another study also proposed a wireless network monitoring system connected to an array of small capacitive sensor probes installed around a foundation for observing scour and sediment deposition processes; this system is similar to a sonar scanning approach [31].…”