Mitigation of Lightning-Induced Overvoltages Using Shield Wires: Application of the Response Surface Method

The power quality of a distribution system is widely affected by some important external factors such as lightning events that can induce dangerous overvoltages. The most widely employed protection measures against lightning overvoltages are the use of shield wires and/or surge arresters and increasing the line insulation level. The shield wire beneficial effect is widely demonstrated in many studies, where it is shown that a significant reduction in the induced voltage magnitudes is achieved. This paper presents an analysis on the main parameters that influence the performance of a shield wire to mitigate lightning-induced overvoltages in MV lines. The proposed analysis is based on a statistical method, the Response Surface Method, which permits to obtain the equation of the surface that best approximates a given model. The proposed methodology is applied to a realistic situation of a rural distribution line.