Laboratory Evaluation of Electromagnetic Pulse (EMP) Hardness Testing Concepts for Electrical Conduit Systems

摘要

Four concepts were evaluated for potential use in testing the electromagnetic shielding integrity of metal conduits: the Hall effect, standing wave coupling, microwave resonant cavity, and diffusion current-leakage current comparison. Existing technology for hardness verification and defect location was reviewed for comparison with the new methods. Because of the phenomena involved, the four concepts are mainly for use with nonburied conduits. In addition, each method has its prospective application limited by one or more drawbacks to implementation: Hall effect devices require direct access to the conduit system and are subject to geometry-dependent variables; with standing wave coupling tests, it may be difficult to maintain a transmission line configuration for the conduit system; the microwave resonant cavity method also requires direct access to the conduit and its greatest potential is for testing of specific conduit components; low frequency phase comparison only verifies hardness, so defects must be located by another test. None of the new methods can be recommended without further development and field evaluation.