A diagnostic system for live electrical joints in power transmission systems

✍ Scribed by R.-D. Rogler; H. Löbl; J. Schmidt

• Publisher: John Wiley and Sons
• Year: 2007
• Tongue: English
• Weight: 555 KB
• Volume: 7
• Category: Article
• ISSN: 1430-144X
• DOI: 10.1002/etep.4450070506

✦ Synopsis

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.