The paper presents a method to identify the location of direct lightning strikes to overhead transmission lines and potential subsequent flashover(s). The method is based on the electromagnetic time reversal theory and relies on the use of a single measurement point to record voltage transient signals originated by a direct lightning strike either on the phase conductors or shielding wires, and possible flashovers. The measurement system is supposed to be installed on the secondary winding of the transformer located at the line feeding substation. The performance of the proposed method, applicable for different power network topologies, is validated by using different numerical simulations applied to various case studies. The paper also discusses the impact of the grounding system model, high-frequency transformer model, presence of surge arresters as well as soil electrical parameters.