Rogowski Coil Sensors for Measuring Lightning Strike Currents on Mechanical Aircraft Joints

Abstract

The study of currents flowing through the fuselage of an airplane is of vital importance from the standpoint of electromagnetic compatibility due to their potential for causing severe failures on embedded systems. Direct lightning strikes can produce extremely high currents propagating through the fuselage panels. Such high currents are critical when flowing through mechanical joints, a point of complex analysis due to the existing electrical discontinuities. Consequently, understanding the propagation of these currents is vital for protecting avionics through improved joints not only from a structural standpoint, but also from an electromagnetic perspective. In this article, we propose designing and validating a Rogowski coil sensor to measure the current flux through the mechanical joints that attach different fuselage panels. This sensor is theoretically analyzed, and a circuit model is provided. Then, a printed circuit board (PCB) Rogowski coil is designed and manufactured for measuring high-intensity pulsed currents with a bandwidth of 10 MHz. Subsequently, the probe is characterized through its S-parameters. Next, its equivalent lumped-element circuit is extracted and simulated for validating the sensor’s transient response. Finally, the Rogowski coil sensor is experimentally evaluated in the measurement of a surge current pulse that emulates a real scenario.