Localisation of Power Cable Discontinuities Using High Frequency Couplers for Time Domain Reflectometry

H. Edin, R. Papazyan, V. Dubickas and T. Ramanauskas

ime domain reflectometry (TDR) has been successfully used for the localisation of transmission line discontinuities in various applications. However, its practical use for service installed power cables has been limited due to a number of major challenges. One of them is connecting the measuring system to the cable, dealing effectively with the signal distortion from the high voltage (HV) terminations. Another concern is the ability to perform TDR measurements and place the sensors without introducing changes to the cable construction and installation. These issues are addressed with the use of high frequency signal couplers.

The paper describes the measuring system as well as the results from the localisation experiments. The TDR technique is demonstrated for the localisation of cable splices and damaged integrity of the ground screen. Different types of power cable sensors have been constructed and investigated. Calibration of the sensor signals is performed. Furthermore, the sensitivity of the different sensors is investigated in relation to the ability to detect reflected signals from these types of cable discontinuities.

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