A preliminary study of the factors which influence the sparkover of insulators in dry air and with dry air SF6 mixtures

All of the data given in this report are the result of hundreds of flashover tests with no resulting physical damage to the test specimens. Each Vd and V value given represents an average of ten or more successive tests. More work is planned to lend further credibility to the reasons mentioned for the Vd/V values obtained. Impulse and non-uniform tests are contemplated together with photo-multiplier techniques to measure the pre-breakdown discharges in the series gap. All of the necessary figures cannot be included here due to space limitation, but will be included in a final published report when the work is completed.