Advancements in insulation coordination for improving lightning performance of distribution lines

The paper is motivated by the results obtained in a joint project between the Brazilian electric distribution utility AES Sul, the Federal University of Itajubá and the University of Bologna. It deals with some aspects relevant to the assessment of the lightning performance of medium voltage (MV) overhead power distribution lines and of MV distribution feeders mainly composed by overhead lines. In particular, the paper focuses on the effects of direct strokes to the line conductors and on the representation of both the AC voltage at the utility frequency and the flashovers of the insulators. Results are presented with reference to lines with standard or compact configuration as well as to a feeder with complex topology.