Recent power quality studies have been focused on the source-identification of voltage disturbances at distribution network busses. This paper describes a method aimed at correlating indirect-lightning events with power systems relay operations, associated with voltage dips. The proposed method, based on the coordinated use of the Italian lightning location system CESI-SIRF, the Italian monitoring system of protection manoeuvres CESI-SAM, and the availability of an advanced simulation tool for the accurate simulation of lightning-induced voltages on complex power networks, namely the LIOVEMTP code, is applied to the real case of an Italian distribution system. The LIOV-EMTP code is also employed along with a statistical procedure based on the Monte Carlo method to carry out a statistical analysis aimed at assessing the lightning performance of a typical Italian distribution line.