Dielectric Recovery Property Measurements of CO_2 Arcs under Free Recovery Condition using Power Semiconductors

摘要

This paper presents dielectric recovery properties of residual C0_2-gas arcs in a nozzle under free recovery condition, which was realized by the highly temporally resolved operation of insulated gate bi-polar transistors (IGBTs) connected in parallel to arcing electrodes. The recovery properties was measured by adjusting the application timings of the quasi transient recovery voltage (TRV) with a peak value of 8.4 kV peak and a rate of rise of recovery voltage (RRRV) of 2 kV/μs. After a specified delay time t_d from initiation of arc decaying, re-ignition occurred when the post-arc phase did not have a dielectric strength enough to withstand the quasi-TRV. The current and voltage measurements and high speed photography were conducted simultaneously. From these results, we determined the interruption success rates for different delay time t_d. It was found out that 200 L/min of CO_2 gas flow needs t_d = 200 μs to quench the arc enough to withstand the quasi-TRV application; 100 L/min of CO_2 gas flow, t_d = 300 μs. In every case of interruption failure, the thermal interruption failure occurred due to the residual arc channel heating by the post-arc current.