Design and Implementation of a Human Machine Interface for Online Cable Condition Monitoring

Cable integrity in nuclear power plants (NPPs) has increasingly become an area of major focus, especially after decades of operation. Many NPPs are going through extensive refurbishment to extend their service life for another thirty years, among which cable condition monitoring is an important area of focus. Spread-Spectrum Time-Domain Reflectometry (SSTDR) enables online fault monitoring of cables without requiring disconnection from the sensor, allowing defect detection to be performed while the cable remains in service. Experimental and simulation findings reported in the literature demonstrate that SSTDR, combined with enhanced processing algorithms, is an effective approach for online cable defect detection and locating. In a typical NPP, several thousand cables remain in continuous operation for decades, while a representative cable-monitoring laboratory may age 100 to 150 cable samples simultaneously to characterize failure profiles. However, existing SSTDR implementations are typically operated through Python-based scripts, which adds complexity to routine use. To address this limitation, a Human–Machine Interface (HMI) was designed and implemented to enable practical, user-friendly online cable condition monitoring, thereby eliminating the need for direct interaction with Python-based scripts. The designed HMI plays a pivotal role in translating raw SSTDR responses into actionable diagnostic information: It displays essential parameters and test settings while restricting access according to user privilege levels, ensuring secure and role-appropriate data handling. The experimental setup consisted of a 5 m cable section housed within a heating chamber to represent the thermally stressed portion of the cable under investigation. Reflected and processed responses at Bits 10 and 11, corresponding to equivalent cable lengths of 1.68 m and 3.36 m, respectively, provided spatially resolved indicators of signal variations along the cable under thermal loading. By presenting these results through an intuitive and accessible interface, the HMI not only ensures user-specific accessibility of SSTDR responses but also highlights cable failure risk in real time, thereby enabling proactive, informed maintenance decisions by cable testing, and maintenance operators. This underscores the HMI’s significance as a critical bridge between advanced SSTDR diagnostics and practical, field-level decision-making in nuclear power plant cable integrity management.