The Sandia Lightning Simulator (SLS) allows test objects to be subjected to simulated lightning currents up to severe levels. The SLS can be configured to produce either one or two simulated strokes, with or without continuing current. It can deliver a maximum peak current of 200 kA for a single stroke, 100 kA for a subsequent stroke, and several hundred Amperes of continuing current for hundreds of milliseconds. The simulator output waveform is comparable to natural lightning in terms of the pulse rise and fall times, peak current, and continuing current amplitude and duration.
Test configurations include direct-attachment lightning, (where the simulator is connected to or arcs to the test object), burn-through (which incorporates continuing current), and nearby magnetic fields due to the strokes. The SLS can be used to certify or evaluate hardware or to perform basic or applied research.
The simulated lightning strokes are generated by high-voltage (up to 1.6 MV) Marx banks housed in two large oil tanks that provide high-voltage insulation. The peak current can be varied depending on the charge voltage of the Marx banks. Triggered crowbar switches in each tank are used for pulse shaping and ultraviolet lasers trigger the crowbar switches at a predetermined time. Continuing current, when required, is delivered by a large motor-generator set.
SLS machine diagnostics include current and voltage measurements taken for each shot. Typical test object diagnostics are current viewing resistors and transformers, Rogowski coils for measuring current derivatives, and voltage dividers. Other compatible diagnostics are pressure transducers, temperature sensors, and electric and magnetic field sensors (D-Dot and B-Dot, respectively). To minimize coupling from the electromagnetic noise generated during a shot, test object diagnostics are housed in a shielded instrumentation box, and their signals are fed through a fiber optic system back to the screen room.
Performance Characteristics of the SLS Facility
|Peak Current||≤ 200 kA|
|Current rise time||1 to 5μs|
|Pulse width (@50% level)||50 to 500μs|
|Number of Pulses||1 or 2|
|Interval between pulses||variable|
|Average current||100s A|
|Duration||≤ 1 s|