Uprating of power transmission lines in Israel Electric Corp

Impelled by an energy consumption growth of about 7% per year, the Israel Electric Corporation began the transmission line uprating project. It was decided to raise the permissible conductor temperature to 100°C on condition that safe clearances will be retained at this temperature. The lines were originally built for keeping the clearances at 60°C. Furthermore, a few years ago the clearance requirements were raised. Thus, the main engineering efforts were directed to line measurement techniques and conductor elevation methods. Novel sag/clearance measuring techniques with appropriate accessories and computer programs were developed, one using a total survey station and second based on an ultrasonic conductor height meter and a laser distance meter. For conductor elevation when needed, several technologies are in use. The simplest ones are additional conductor tension with supplementary vibration protection means or replacement of porcelain insulators by shorter synthetic ones, and the most extensive include a pylon addition, replacement or elevation. An original suspension device was developed providing the conductor suspension point to be elevated to the cross-arm level. A few 161 kV lines have already been uprated, and the project continues