An experimental method to determine the electrostatic field enhancement factor of a practical conductor surface

Electric fields and electrical insulation

“…In the late 1980s, following a revival of interest in surface roughness effects through an EPRl project, it was realized that the original protrusion studies suggested an indirect method of determining the field enhancement factor for the surface of a practical conductor [70]. The essence of the method can be appreciated from Figure 10, which indicates that as ( p / H J + -, < tends asymptotically to some limiting value, elim.…”

“…The essence of the method can be appreciated from Figure 10, which indicates that as ( p / H J + -, < tends asymptotically to some limiting value, elim. In [70], it is shown theoretically that in fact To obtain an asymptotic limit for <, it is desirable to undertake (io measurements over an extensive pressure range. In reality however, this is not possible.…”

Illusory Paschen curves associated with strongly electronegative gases

“…Although SFs is a non-ideal gas, with respect to the breakdown analysis, this feature may be taken into account by replacing p with the compressibility-corrected gas pressure p z , where p z , is given by Z ( p , T ) is the compressibility factor (< 1) for the gas at pressure p and temperature T. Values for this factor can be derived from the expressions given by Vibholm and Mollerup [17]; see also the Appendix in [18]. In turn the pr substitution leads for SF6 to ( E / J I~)~;~ = 87.9 kV(mm MPa)-l at 20°C [18].…”

On the electrical breakdown of gaseous dielectrics-an engineering approach

“…Although m is generally an unknown constant the value of this factor will normally be of the order of 10 or less, see Loeb [56]. Recently, an experimental technique has been developed [57] which allows the m value of a practical surface to be determined. Results confirm that an upper limit of 10 for such surfaces is a reliable measure.…”