EIT for the condition monitoring of wood poles carrying overhead power lines

Decay caused by the fungus Lentinus Lepideus is a major cause of failure in wood poles carrying overhead lines (Morris and Calver, 1985). The metabolism of the fungus produces ions, changing the impedance properties of the wood. The authors' aim is the development of a low-cost tomographic sensor to predict the loss in pole strength resulting from decay; the strength is defined as the pole's resistance to bending forces and is dependent on both the size and position of areas of decay. A previous low-cost approach to this problem used ultrasound (Tomikawa et al., 1986), but this is highly sensitive to transducer contact quality. Electrical impedance tomography (EIT) is an alternative method that can be used for this application.