Multi-Objective Optimization for Lightning Protection in Distribution Networks: A Novel Approach Based on Design of Experiments

This paper focuses on the identification of a proper protection strategy against lightning effects on overhead distribution lines. Particularly, a multi-objective optimisation problem is formulated to contemporaneously take into account the flashover rate and the cost of the protection devices. The random nature of lightning events needs to be considered to find optimal protection. Traditional approaches typically use the Monte Carlo method to reproduce large series of lightning events that vary in location, current intensity, and current ramp rate. However, the high computational effort of the Monte Carlo approach makes it difficult to carry out the above analysis, especially when dealing with complex networks. Thus, in this paper, the Design of Experiments is proposed as the statistical tool to characterize lightning events. More specifically, full factorial design and Taguchi arrays are used which allow for significantly reducing the computational effort. Numerical applications on an actual distribution network located in Italy allowed a comparison of these methods to the Monte Carlo approach. The results evidenced the effectiveness of the proposed approach in terms of computational effort and accuracy of the analysis.