Generation of DC High Voltage Pulse for Hipot Testing using PFN based Marx Generator

Abstract

The Hi-pot test is carried out on transmission line cables for checking insulation condition. In this paper, the design and simulation of circuit for hipot testing of cables is reported. The circuit essentially comprises of Pulse Forming Network (PFN) based Marx Generator. Marx Generator basically generates a high voltage pulse from a low voltage DC supply. The Pulse Forming Network (PFN) is used to store the exact amount voltage required for hipot testing. The pulse parameters in PFN circuit can be varied and controlled by altering the PFN and the load connected to the PFN. For simulation purpose P-Spice software is being used. Simulation results are obtained for 20 kV charging voltage, 30kV max pulse voltage with 5µs pulse-width. Single stage and multi stage of PFN based Marx generator required for Hi-pot testing are simulated and discussed. Hardware implementation of scaled down circuit is done and satisfactory results are obtained.