Double and Single-Break Vacuum Interrupters for High Voltage Application - Experiences on Real High-Voltage Demonstration-Tubes -

SUMMARY High voltage switchgear applications often use the gasblast system normally based on SF6 as an arcextinguishing medium. This paper describes switching and dielectric experiments with vacuum demonstration tubes for the 84 kV voltage level. The investigations were performed with two different tube designs. The difference between these objects is the number of breaker units per tube and slight deviations in the shielding arrangement. The tubes were tested under different switching conditions, especially terminal fault, short-line fault, capacitive and inductive current switching. The switching results of double and single-break units were discussed. In addition to the pure switching experiments, the dielectric strength after these tests was determined. The dielectric experiments show the gain of dielectric strength caused by conditioning effects and were carried out with alternating voltage (AC voltage) and lightning impulse voltage (LIV).