Robust Lightning Indirect Effect Protection in Avionic Diagnostics: Combining Inductive Blocking Devices With Metal Oxide Varistors

The combination of iron core inductors and metal oxide varistors has been modeled and experimentally characterized to propose a robust protection system for indirect lightning effects in avionic environment. In particular, a numerical procedure to design transient limiters with high current rating, low clamping voltage, and low degradation rate is presented and described in detail. The protection systems are modeled using a circuital approach based on the diffusion equation, which is implemented in a finite difference time domain scheme. Two different modeling approaches to represent the nonlinearity and the hysteretic behavior of an iron core inductor are presented and discussed. Simulation results are verified by pin injection tests following the specific standards for avionic diagnostics.