Improved calculation for corona loss on three-phase power transmission lines

This paper presents an improved method to calculate the corona power loss and the ground-level electric field values for three-phase power transmission lines. The charge simulation technique is applied in which the surface charge on the stressed conductors as well as the space charges around each conductor are represented by two discrete sets of unknown infinite line charges. Satisfying properly chosen boundary conditions at the transmission-line conductor surfaces results in a system of linear algebraic equations whose solution evaluates the unknown line charges. The emission of ions from a conductor surface is assumed to take place when the magnitude of the charge simulating its surface charge exceeds an onset value based on a pre-defined corona onset field value for both positive and negative half cycles. The simulation space line charges are displaced back and forth to the conductor by the action of the electric field whose magnitude and direction depends on the simulation charges in the conductor and in the surrounding space. A recombination process takes place whenever charges of opposite polarities meet together. The calculated corona power loss for three-phase power transmission lines agreed satisfactorily with those reported earlier