Defect Diagnosis of High-Voltage Cables by Leakage Current Analysis of Swept Signal Injection

High-voltage cables are critical components in power grids, essential for ensuring safe and reliable energy transmission. While leakage current monitoring is a key method for diagnosing cable aging, traditional approaches suffer from limitations such as insufficient sensitivity and vulnerability to external electromagnetic interference, which hinder their effectiveness in cable insulation detection. This paper proposes a novel leakage current aging diagnosis technique for high-voltage cables based on the active injection of swept signals. By sequentially injecting equal-power harmonic signals, the technique excites defect locations within the cables and amplifies the corresponding harmonic components of the leakage current, enabling precise, on-line, non-invasive monitoring of cable aging. Simulation results demonstrate that this method significantly enhances the accuracy and reliability of cable insulation monitoring, offering valuable technical support for the operation and maintenance of high-voltage cables.