Insulation monitoring system for XLPE cable containing water sensor and optical fiber

An all-purpose insulation monitoring system for XLPE (cross-linked polyethylene) cables in hot line has been developed. The system measures the dielectric dissipation factor and DC component of charging current, i.e., the two factors which are attracting much attention for evaluation of cable insulation in hot line, and detects water penetration and longitudinal temperature distribution in the cable. Water penetration and longitudinal temperature distribution in the cable are detected by a water-penetration sensor and an optical fiber, respectively, both built into the XLPE cable. The monitoring system has been installed in an actual circuit having a test cable, and a proof test is being conducted on the circuit