Recent Lightning Induced Voltage Test Technique Investigations
Abstract
The aircraft under test must have a spaced set of return conductors around the aircraft to maintain a realistic electromagnetic field condition. The aircraft, the return conductors, and the facility where the tests are conducted form sets of short transmission lines. The travelling waves propagate in a transverse electromagnetic (TEM) mode at the speed of light. However, due to reflections and refractions at the junctions of different impedance sections of the aircraft (i.e., wing and tail attachments) the bulk of the wave energy travels distances considerably farther than the nose-to-tail dimension. Consequently, the wave appears to take longer to reach the tail, which had been interpreted as a slower propagation velocity. Travelling electromagnetic waves reflecting and refracting on the aircraft transmission lines control the response of the system during the initial few microseconds of the test. For slowly rising test current waves, (> or = r microsec) the transmission line characteristics of the test circuit can be ignored. At current risetimes of 1-5 microsec, the aircraft can be terminated in a characteristic resistance. At very fast short transmission lines of different impedances. In the limit, the system itself will govern the current risetime which can be injected due to the reflection/refractions and the low pass filter characteristics of the system. With present configurations, current risetimes faster than 100ns do not appear possible.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1983
- Accession Number
- ADP002193
Entities
People
- Keith E. Crouch