Simulation of transmission line performance under lightining strikes using the FDTD method

Nowadays in the unregulated market the utilities are concerned to avoid unexpected outages. Transmission lines are responsible for interconnecting the generation facilities and load centers and as they run through their right of ways they are subjected to a variety of environmental stresses. One of these stresses is the atmospheric discharge or lightning strokes. It is important to know how the line behaves when subjected to such a stress in order to design its insulation to withstand to them. Numerical simulation is a tool to aid engineers to get a better knowledge on how the transmission system behaves after being hit by a lightning stroke. This paper shows how the Finite Difference Time Domain (FDTD) method can be used to determine the voltage on an insulator string when a lightning strikes the tower or the line.