Diagnostic Study on Medium Voltage Cable Condition Assessment Using Collective Testing

Power cables are extensive capital investments that incur substantial expenses for installation, maintenance, and potential repairs causing financial loss resulting from cable damaged. To mitigate these risks, it is imperative to implement effective monitoring of cable health with early detection of deterioration. This research addresses the challenge of evaluating the health of medium-voltage cables insulated with cross-linked polyethylene (XLPE), a material having its exceptional thermal stability, chemical and environmental resistance. XLPE insulation is susceptible to degradation over time due to ageing, mechanical stress, moisture, and electrical overloading, despite its advantageous features. Very low frequency (VLF) tangent-delta testing was utilized to monitor dielectric loss and examined the insulation's present condition in order to assess the health of in-service XLPE-insulated medium-voltage cables. The evaluation included important variables such as the dielectric loss tangent, dielectric absorption ratio (DAR), and insulation resistance (IR). Cable ageing factor was calculated and analysed using these indicators, which provided a comprehensive overview of the insulation's health. The outcomes of this study demonstrate that VLF tangent-delta testing is an effective method for diagnosing the condition of XLPE-insulated cables. The analysis revealed specific degradation patterns and enabled the estimation of cables' remaining operational life. These insights facilitate proactive maintenance strategies, enabling asset managers to prioritise replacements and improve system reliability. As a result, the risk of unexpected failures is reduced, and maintenance costs are optimised.