Characteristics of Ultrasound Induced by Partial Discharge in Power Cable

When the discharge occurs, charged particles and neutral particles collide. In the process of collision, the interaction between charged and neutral particles in the ionized gas leads to a perturbation of the surrounding air, which generate ultrasound. In the case of voids in the cable insulation, repeated partial discharge is one of the main sources of insulation degradation, which may lead to a complete breakdown of the insulation. Therefore, it is important to monitor the condition of cable insulation through partial discharge measurement. In this paper, a cable simulation model is established in order to study the propagation and attenuation characteristics of ultrasound generated by partial discharge. This cable model has a built-in optical fiber that can be used to monitor partial discharges. The results show that the attenuation of ultrasound from XLPE insulation layer to the fiber core is 58dB-64dB.