FDTD Calculation Model for the Transient Analyses of Grounding Systems

Transient performance of grounding systems is simulated using the finite-difference time-domain (FDTD) method for solving Maxwell´s equations. The derivation of the transient current is first adjusted to obtain accurate impedance. Then, the FDTD calculation model is optimized to predict the grounding system impedance accurately without resulting in huge computational resources. From evaluation, the direction parallel to the connecting line is supposed to integrate the transient voltage. The transient voltage should be integrated 20 m in length and the reference electrode to be 30 m from the grounding system, and these lengths should be further enlarged for a large dimension grounding system. The transient impedance of the five lightning current components is very close to each other except the multiple burst, and the current should be injected close to the ground.