Discharge detection and measurement in voids in solid dielectrics

Insulating systems invariably contain some cavities or voids entrained within the insulation or at boundaries between dielectric and conductors. The paper presents experimental results obtained in an investigation of the factors affecting the discharge characteristics in voids in solid dielectrics. An E.R.A. discharge detector was used for detection and measurement of discharge magnitudes. The dependency of the discharge magnitude in voids on; the applied voltage, the void dimensions and the duration of the applied voltage was investigated experimentally. Test results also indicate that the discharge magnitude-applied voltage characteristics exhibit same hysterisis. This hysterisis effect is more pronounced for deeper cavities.