Experimental Research on Break Dynamic Insulation Characteristics of C 4 F 7 N/CO 2 Mixed Gas

The insulation strength of high-voltage switchgear opening and closing break is the basis to ensure its safe operation, and it is also one of the important factors affecting its successful closing and breaking. In order to study the break insulation characteristics of the mixed gas of perfluoroisobutyronitrile (C 4 F 7 N) and carbon dioxide (CO 2 ), Build a test and research platform for dynamic insulation characteristics of C 4 F 7 N/CO 2 mixed gas break of the prototype circuit breaker closing-opening process under no-load high DC voltage, Measure the base pressure of 0.7MPa arc extinguishing chamber, the dynamic breakdown voltage of pure SF 6 , 5%C 4 F 7 N/95%CO 2 , 9%C 4 F 7 N/91%CO 2 and 13%C 4 F 7 N/ 87%CO 2 mixed gas, study mixed gas break insulation strength changes. The results show that, compared with pure SF 6 , C 4 F 7 N/CO 2 mixed gas break dynamic breakdown voltage dispersion is greater, the expected penetration time is longer than SF 6 ; increase the content of C 4 F 7 N in the mixed gas, The rate of change of the dielectric strength of the mixed gas break is improved.