Corona Losses Between Wires at Extra High Voltages-II

Results of corona loss tests upon three sizes of cables at voltages varying from 100 to 620 kv. and spacings from 18 to 38 feet are reported from the Engineering Experiment Station of Purdue University. These tests results, reduced to the standard 1000 feet of transmission line, are compared with corresponding values calculated from Peek's formula for similar conditions of operation. A description of the tower line and method of measurement of the losses in the high-voltage circuit is included. An empirical equation has been developed which approximates quite closely the relation between corona loss and voltage for different spacings. The variations of the empirical coefficient of this equation are indicated for 2/0 and 4/0 cables. Three methods of attacking the problem of modified transmission line design for the elimination of excessive corona losses between wires at extra high voltages have been outlined for further research and study. I. Calculation of Capacity and Corresponding Radius of Equivalent Coronal Conductor and Its Relation to Voltage between Wires. II. Determination of Corona Losses between One Wire and Ground. III. Photographic Reproduction of Equivalent Electrostatic Field Surrounding Model Conductors with Proportional Spacings between Wires and Ground. The paper should be considered a progress report to be enlarged and analyzed further at a later time.