On-Line Cable Condition Monitoring Using Natural Power Disturbances

Abstract

On-line cable insulation condition monitoring can significantly reduce the outages caused by insulation failure. This paper proposes a new method to achieve this by utilizing the natural power disturbances originating from outside of the cable, such as capacitor switching and fault transients. In this method, the relative permittivity of the cable insulation is used as the indicator to be monitored, which is closely associated with cable tanδ. The relative permittivity is extracted from the power disturbances and their responses, which are of sufficient strength and a wide range of frequencies. This method is beneficial to the on-line monitoring for it does not need the accurate remote synchronized phase angle information. Case studies and sensitivity studies demonstrate the good performance of the proposed method.