Combined Mechanical and Thermal Behaviour of Overheat Line Conductors

Transmission lines are the backbone of electrical power girds. In Europe, a widespread intermeshed grid was formed from the local power supplies during the last century. With the change in the operation mode as a result of the liberalisation of the energy market, the operators tend to exploit the existing potentials of transmission systems. One point of interest for an overhead line are the active parts of the current path like conductor, joints and fittings. Especially components, which are under mechanical stress and conducting the load current, are critical parts for the personal and system safety. This combined stress is significant for the condition and behaviour evaluation of the equipment. In this work, the typical Austrian 230kV aluminium conductor steel reinforced (ACSR) overhead line conductor was chosen in respect to evaluate the thermal-mechanical behaviour. With a realistically model of the elongation behaviour, sag calculations, which are the base for safety clearance or thermal rating systems, can be made with more accuracy. As the investigations shows, the irreversible elongation of the conductor affects the thermal behaviour of the sag of overhead lines significant.