Vacuum Insulator Flashover Measurements for Microsecond Pulses
NAVAL RESEARCH LAB WASHINGTON DC PLASMA PHYSICS DIV
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The flashover characteristics of the watervacuum insulator assembly of the Gamble II pulsed power generator at the Naval Research Laboratory NRL were investigated to determine the insulators applicability for use with the recently assembled Hawk generator, which features inductive storeplasma opening switch POS technology. Hawk produces a 1-microsecond voltage pulse with a peak value of 265 kV at the vacuum insulator during the POS conduction time. When the POS opens, a voltage pulse as high as 1.5 MV can be produced at the switch. The Gamble insulator was originally designed for -2 MV, 75 ns voltage pulses. Gamble II was re-configured for a long-pulse mode to produce a 1 MV, 1.5 microsecond, wide output pulse for these tests. Flashover data will be presented for voltage pulses of 556 to 843 kV with the time from the beginning of the pulse to flashover ranging from 0.8 to 2.25 microsecond. It was found that the results did not follow the familiar t-16 relationship for flashover. Nevertheless, the performance was more than adequate for this application and an identical insulator has been used successfully on Hawk for nearly a year.
- Electric Power Production and Distribution
- Plasma Physics and Magnetohydrodynamics