A Study of Residual Voltage for Diagnosis of Electrical Power Cable Used in Nuclear Power Station

摘要

This paper describes the theoretical equation for residual voltage and the relationship between irradiation dose and residual voltage for electric power cable used in a nuclear power generating station. At first, assuming that the depolarization has a distribution in relaxation time which obey the Cole-Cole equation, we can derive the equation for the residual voltage. From theoretical and experimental investigation it is found that the residual voltage is not influenced by cable length. This is important merit of the residual voltage as the nondestructive diagnosis. When irradiation dose is more than 500 kGy, the residual voltage exhibits a peak. As the dose is increased, the peak moves to the shorter time region. We will discuss the relation between the movement of peak and the resistance of insulating materials.