Electrical breakdown of short spark gaps with several electrode materials in atmospheric air at AC (50Hz) and ramp voltage (10 kV/µs)

Summary

Within this paper the investigation of electrical breakdown behaviour of short, quasi-homogeneous spark gaps in atmospheric air with several electrode materials (e.g. copper, aluminium, graphite and composite materials) at AC voltage (50Hz) and ramp voltage with a steepness of 10 kV/µs will be presented. Investigations were carried out for breakdown distances in the range of 0.5 mm up to 5 mm. The investigated electrode arrangements are classified by a degree of homogeneity in the range of ? ˜ 1 - 0.85. Initially, the influence of electrode material on the breakdown behaviour for AC – 50 Hz stress by using metallic, non-metallic and composite materials in atmospheric air will be presented. The theoretical background is given by Paschen´s law. The measured breakdown voltages will be compared with the calculated values from Paschen's law. For the evaluation, a comparison between the work function of the studied materials and the measured breakdown voltages will be made. The coefficients of ionization and electron emission ? will be estimated for several materials. Furthermore the electrical breakdown behaviour of selected electrode materials in atmospheric air under stress of AC – 50 Hz will be compared with electrical breakdown behaviour at ramp voltage stress with an approximated steepness of 10 kV/µs. The significant differences relating to the measured breakdown voltages with several electrode materials will be presented and discussed.

Additional informations

Authors

KASDI Ahmed, ZEBBOUDJ Youcef