A diagnostic system for live electrical joints in power transmission systems

Abstract

The resistance of an electrical joint increases depending on load current and environment until the temperature of the joint reaches a critical level, i. e. hot spots occur. To avoid such failures the joints have to be diagnosed and, if necessary, maintained. A widely applied method to inspect electrical joints is to measure the temperature rise and to compare it with empirical limit temperature rises that are assigned to several decisions. Due to unconsidered parameters this method is not sensitive enough to allow a long‐term maintenance concept. To overcome this shortcoming, the resistance of the joint has to be determined from the measured temperature. All the processes of producing, transmitting and storing power are modelled by a thermal network in which the resistance is the only unknown quantity. It can be ascertained by comparing measured and calculated temperatures. The resistance is used to determine the residual life time which depends strongly on this momentary resistance of the joint and the further load current of the line. This method will be described in a following paper.

Increasing the Pressure‐Free Stripping Capacity of the Lithium Metal Anode in Solid‐State‐Batteries by Carbon Nanotubes

“…The shift to higher frequencies observed for pure lithium electrodes may be explained by Joule heating of the few contact spots left, due to current focusing through these. [ 44,45 ] However, the contact spots after stripping Li–Mg alloys are more homogeneously distributed, [ 17 ] which should reduce the effect of Joule heating. Following this explanation, the contact spots after stripping Li–CNT electrodes should also be distributed more homogeneously as for Li–Mg when compared to lithium.…”

“…From that point on, the CNTs act as a contact mediator, maintaining contact to the SE and acting as a 3D distributed anode scaffold. Another effect at play could be the increased ionic conductivity of contact spots due to Joule heating, [ 44 ] which may be one explanation for the improved stripping after the kink.…”

On Smart Geometric Non-Destructive Evaluation: Inspection Methods, Overview, and Challenges

“…The most commonly used tools for temperature measurements are thermal cameras. Thermal cameras have been used to diagnose electrical junctions in power transmission networks [ 33 ], monitor the thermal state of other electrical installations automatically [ 34 ], assess particular qualities in various materials, and to assess the erosion resistance of silicon rubber composites as in [ 35 ]. It has proven to be an effective and economical method for evaluating concrete [ 3 ].…”

RobotEye Technology for Thermal Target Tracking Using Predictive Control

“…After estimating the position of the thermal target with respect to the vision camera, it is calculated with respect to the eye in the azimuth and elevation space using equations (1) and (2). The conversion requires the extrinsic parameters such as and .…”

“…In the last few decades, due to the advancement of the state-of-the-art technology, thermal vision systems find application in many areas [1]. For example, in [2] such systems are used to detect faults in the electrical transmission lines which can save millions of dollars in maintenance of power systems. Nevertheless, such sensors are quite handy in the stress analysis of structures, which is also known as thermoelastic stress analysis.…”