Advanced Polymeric Cable Degradation Diagnostics using Time Domain Reflectometry Technique

Abstract

Power cable is an important medium to transmit electricity from generation to transmission and distributing to end users. Despite taking various preventive measures, there are still numerous reports on power outages due to power cable failure. Power utility companies have been using time domain reflectometry (TDR) technique to locate fault in cable. However, the cable diagnosis often consumes long period of time due to uncertainty of cable fault signatures from the TDR result. Therefore, this study aims to investigate the cable fault signature from the TDR result so that fault in the cable can be identified quickly for replacement work to take place. This study consists of TDR simulation work using MATLAB Simulink and validation of simulation results with TDR experiments. Power cable is first modelled without any joint followed by a cable with two joints. Conditions of every cable section is varied for each cable model to replicate all possibilities of cable degradation along the cable. Simulation results from all cable configurations are then validated with TDR experiments. Both TDR simulation and experimental results have shown consistencies in the TDR reflections with distinct signatures where it can be detected by observing the delay and change in magnitude of cable joint reflections. Greater delay shows higher level of degradation in the cable. Degraded cable with joint can be identified from the cable joint reflection that has a higher magnitude. With these TDR reflection signatures, degraded cable can be identified and sectionalized for cable replacement to take place immediately and thus, minimizes the electricity disruption time.