Experimental Study on Cable Joint Temperature Measurement Technology Under Step Current

For a power cable,the temperature of its joint is closely related to its running state,thus measuring the temperature provides the basis for the cable's state maintenance and dynamic capacity enhance.We installed temperature sensors on different parts of a 10 kV cable,including the surface of prefabricated joint,the copper shell,the copper shield of cable body,and the conductor core,and the temperature response curves of these sensors with different step current forms were obtained and comparatively analyzed.The results show that the temperature of the surface of the prefabricated cable joint is less influenced by environmental temperature,and can react faster to the temperature change of conductor core,therefore,it is more suitable to install temperature sensors on the surface of prefabricated cable joint.Then a temperature model of cable joint was established by the software ANSYS with some uncertain parameters calibrated,and the steady state temperature of conductor core was calculated with measured surface temperature as raw data;the maximum error between calculated value and measured value was 3.9%.Moreover,with the measured temperature of the surface of prefabricated cable joint as input,the transient temperature of conductor core was estimated based on the BP neural network algorithm,and the maximum error between the estimated value and the measured value was 3.3°C,meeting requirements of engineering application.