Reducing PFN marx generator size using nested solid insulation

Current state-of-the-art, high voltage, pulsed power systems above 0.5 GW output power, generally use Marx or Pulse Forming Network (PFN) Marx generator designs. The high voltage insulation of these devices has been traditionally based on either high dielectric strength oil or sulfur hexafluoride (SF6). The dielectric strength of the insulating medium determines the minimum size of the tank enclosure of the system since it determines the maximum voltage standoff between the fully erected Marx output voltage and the tank wall. We have applied our “Nested High Voltage” (NHV) insulation technology to the problem of PFN pulse generator design. This technique uses solid insulation with field grading foils that minimized the distance from the fully erected voltage and the tank wall. This report describes work performed in adapting this technology to building a PFN pulse generator. We believe that this technology will allow size reductions relative to other insulation technologies. The technology also allows integration of the PFN charge power supply into the PFN. Data will be presented on the performance of a 130kV version of this type of device capable of up to 5kA output. We demonstrated that making a “flat” pulse is feasible in this geometry, and we determined that there is an optimal grading technique for this type of design. Both high gradient insulation and pulse generation have been demonstrated and will be described. The systems will be useful in the 50kV - 2 MV range with impedances in the 20 - 200 ohm range.