ABSTRACT
Electric energy is produced at electric power generating stations and transported over high-voltage transmission lines to utilization points. The trend toward using higher voltages is motivated by the increased line capacity while reducing line losses per unit of power transmitted. The reduction in losses is significant and is an important aspect of energy conservation. Better use of land is a benefit of the larger transmission capacity of the lines. An electric transmission line is modeled using series resistance, series inductance, shunt capacitance, and shunt conductance. The line resistance and inductive reactance are important. Phase conductors in extra high voltage - ultra high voltage transmission systems employ aluminum conductors and aluminum or steel conductors for overhead ground wires. Corona is the direct result of high-voltage gradient at the conductor surface. The gradient can be reduced considerably by using more than one conductor per phase. The capacitance of a transmission line is the result of the potential differences between the conductors themselves.
