Challenges in wave-velocity based cable temperature monitoring for widespread implementation in medium-voltage networks

Knowledge on the temperature of the mediumvoltage network is essential for optimising its utilisation. This is even more imperative now many networks are facing increasing congestion restrictions due to the energy transition. Real-time temperature monitoring can reduce the uncertainties from model predictions based on standards, e.g., because of inaccurately known thermal soil parameters and surrounding elements influencing the cable’s thermal state. Information on the insulation temperature in power cables can be extracted from the wave velocity, owing to the temperature dependent relative permittivity. This principle can be implemented in existing monitoring systems for locating partial discharges or cable faults based on the wave velocity. This paper addresses the challenges when employing wave-velocity based temperature monitoring in a network containing different cable types and branched cable connections. A benchmark cable system is adopted to emulate complications from multiple signal reflections in identifying the temperature of individual cable parts within a larger network. When reflection patterns in a waveform can be identified and attributed to a certain cable network location, their shift with varying temperature informs on the temperature of the individual cable segments.