In this paper, the results of the experiments performed on electrical breakdown in CO2 and CO2-O2 mixtures in weakly and strongly non-uniform fields generated with impulse (2/160) µs, AC and DC waveforms are presented. In weakly non-uniform fields, the electrical breakdown field approximately follows 11 kV/(cm bar) when stressed with both AC and DC (positive and negative) waveforms. For positive impulse, the breakdown voltage is higher and the time lag to breakdown is scattered, indicating a lack of starting electrons from CO2 gas. Furthermore, the breakdown strength of CO2 - O2 (10-30)% mixtures is investigated. On application of negative polarity impulse, the breakdown strength is significantly higher than positive impulse in the measured pressure range of 0.3-0.7 MPa in strongly non-uniform fields, contrary to that seen during breakdown in weakly non-uniform fields. Breakdown voltage for negative impulse is further enhanced in a mixture of CO2-O2 (80-20)%.
|Number of pages||8|
|Journal||IEEE Transactions on Dielectrics and Electrical Insulation|
|Publication status||Published - 9 Feb 2021|