Toward a New Understanding of Frequency- and Impedance-Related Failures in Grounding Systems
Abstract: The importance of grounding in protecting structures and electrical systems has been known for over two centuries. However, there are two critical characteristics of damage-causing fault currents which have not been sufficiently explored by engineers in the design and installation of protective grounding strategies: This paper discusses the significant deficiencies in common grounding systems with respect to broadband fault current frequencies (including >60 MHz) and impedance “walls” created by inefficient ground-rod-to-soil interfaces. An examination of the dynamics of high frequencies and impedance mismatches in grounding systems is presented, demonstrating why these systems fail in spite of their adherence to commonly accepted design and testing standards. Broadcast Industry efforts to create a higher degree of damage prevention via grounding, therefore, requires a deeper analysis and understanding of fault current components, characteristics, and events.