Application Studies of Line Arresters in Partially Shielded 138 kV Transmission Lines

The application of arresters on transmission lines has been one of the most effective alternatives for the reduction of lightning flashover rates. This paper reviews previous methods for evaluating lightning performance of lines with arresters. Improved calculation of line outage rates are developed to include power freuency voltage and arrester failure rate evaluations, based on field experience. The transmission lines are modeled in full detail in the ATP program and the outage rates are calculated with Monte Carlo´s method. Probability energy stresses on arresters are evaluated for strokes on conductors and shield wires as a function of tower footing resistance.