Flashover Voltage and Discharge Mechanism of Mixed Gases

1986 Fiscal Year Final Research Report Summary

• Project/Area Number: 60460111
• Research Category: Grant-in-Aid for General Scientific Research (B)
• Allocation Type: Single-year Grants
• Research Field: 電力工学
• Research Institution: The University of Tokyo
• Principal Investigator: KOUNO Teruya The University of Tokyo, 工学部, 教授 (30010705)
• Co-Investigator(Kenkyū-buntansha): CHIBA Masakuni The University of Tokyo, 工学部, 助手 (20011140)
• Project Period (FY): 1985 – 1986
• Keywords: Mixed gas / Discharge voltage / Flashover voltage / Synergism / Sulphur hexafluoride / electro-negative gas / Freon gas / 六弗化プロピレン

Research Abstract

1. A calculation method of flashover voltage of a mixed gas in uniform field using electron energy distribution given by Boltzmann equation, which we have proposed, was convinced in general cases.
2. The relation between the flashover voltage of a mixed gas and the ones of the component gases were made clear by experimental investigation. Used gases are <SF_6> , <CCl_2> <F_2> , <C_3> <F_8> , <N_2> , <O_2> ,Ar and binary mixtures of them.
3. It was both experimentally and theoretically convinced that the flashover voltages of a mixed gas composed of two electro-negative gases having nearly same flashover voltages show the character of synergism and have the maximum value at a mixing ratio which is larger than each flashover voltage of component gases.
4. Some experiments were made to investigate the discharge mechanism in mixed gas in non-uniform field. In non-uniform field, very little amount of a component gas or impurities such as water vapor has a sensitive effect on discharge phenomena.
5. <C_3> <F_6> gas is known as a rare example in which Paschen's law is not valid. Flashover voltages in the gas were measured with and without irradiation by ultra-violet lamp. The flashover voltages without irradiation was much larger than the one with it even in unform field of DC voltage.