Research On FBG-based Cathodic Protection Detection Technology For Marine Wind Power

Cathodic protection with sacrificial anodes is commonly used for corrosion protection of offshore marine power facilities.The national standard uses the size of the potential between the protected metal and the reference electrode to indicate the effect of cathodic protection,but this method is susceptible to electromagnetic interference in the detection process,the reference electrode requires maintenance and debugging before use,etc.To address the above problems,by exploring the principle of the cathodic protection method of sacrificial anode,determine the detection method by measuring the shape and volume of the sacrificial anode to indicate the effect of cathodic protection,and design a set of positioning and thickness measurement in one offshore wind power cathodic protection detection system,the method effectively avoids electromagnetic interference and dependence on reference electrodes.The main contents of this paper include.First,the basic principles of cathodic protection method of sacrificial anode,swept light positioning,ultrasonic action on grating,amplitude modulation and thickness detection are studied.Secondly,the modules of the offshore wind power cathodic protection detection system based on Fiber Bragg Grating(FBG)are designed to realize the excitation of linear frequency swept light,software closed-loop correction of frequency swept light linearity,determination of frequency swept light range,grating ultrasonic sensing and ultrasonic thickness measurement.Again,a thickness measurement algorithm based on spectral demodulation is investigated,the role of the window function is analyzed,the selection of the window function is explored,and continuous ultrasonic sounding is experimented and compared with the theoretical results.Finally,an ultrasonic thickness measurement system was built to measure the thickness of the sacrificial anode metal using the thickness measurement algorithm,and the relationship between the thickness measurement accuracy of the system and the ultrasonic frequency and linearity of the laser was analyzed,and the shape of the sacrificial anode metal was fitted by multi-point thickness detection of the sacrificial anode metal.