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The remote location and position of offshore wind turbine structures severely limits the application of in situ corrosion detection methods such as ultrasonic, acoustic emission, and X-ray. A real-time remote sensing (RTRS) technology can be implemented to provide autonomous detection and monitoring, providing exhaustive and detailed information on the corrosion process. Utilizing the concept of Internet of Things (IoT) through the integration with satellite and terrestrial communication network, iWindCr, a technology development project funded by the Innovate UK, aims to design a wireless sensor network (WSN) of smart miniaturized sensors for corrosion detection and monitoring of the offshore wind turbine structures. This paper discusses the rationale and challenges around the iWindCr WSN design, particularly in the development of a miniaturized system and in relation to the provision of power and power consumption.The later has led to the selection and the integration of the electrochemical analysis techniques, namely open circuit potential (OCP) and zero resistance ammeter (ZRA) on the sensor interface system. The verification of these techniques for the corrosion detection sensor has resulted in a database consisting of the corrosion parameter outputs or threshold values of metals specific to offshore wind turbine structures, in this case tower, foundation, and nacelle (gearbox). The database provides end-users with the benchmark that can be used to detect physical changes during the course of corrosion or passive film damage. These parameters are incorporated in the user interface data analytic software, enabling the quantification of corrosion or film damage.

A Proof-of-Concept (POC) low power-low current wireless sensor network (WSN) for corrosion detection and monitoring of offshore wind turbine (OWT)'s component, entitled iWindCr, has been developed and field trialled in one of the OWTs in the UK south region. This paper reports on the setting up and outcomes of this field trial. The trial has successfully demonstrated the working functionality of the WSN by measuring changes of the Open Circuit Potential (OCP) and Zero Resistance Ammeter (ZRA) electrochemical parameters over a period of time. The state of corrosion and estimated life of an M72 galvanised steel stud, part of the Monopile (MP)transition piece (TP) flanged connection were evaluated using the real-time data from the WSN with reference to the material's corrosion thresholds from the iWindCr database. The paper details the electrochemical analysis processes in relation to the Electrochemical Impedance Spectroscopy (EIS), Potentiodynamic Polarisation Curve (PPC) in addition to the OCP and ZRA techniques. The electrochemical parameters and corrosion threshold values from seawater immersion tests of the steel alloys SS316L and S355, the typical MP-TP materials are presented.