Abstract:

In order to verify C4-PFN arc extinguishing ability in the 145 kV disconnecting switch and the application prospects,C4-PFN-CO₂ mixed gas is selected as the medium for the current interruption experiments.Before the experiments,the saturated vapor pressure characteristics of C4-PFN gas was studied,and the optimal mixing ratio of C4-PFN-CO₂ mixed gas was obtained under the limit of -25 ℃ liquefaction temperature.The maximum proportion of C4-PFN in the mixed gas is 5.8% at -25 ℃.Through the experiments,it can be found that at 0.6 MPa,the arc voltage of the C4-PFN-CO₂ mixed gas is lower than that of SF₆,and the amount of arc energy injection is also smaller.It shows that the energy dissipation rate of SF₆ is higher and the arc extinguishing ability is better.When the pressure increase to 0.7 MPa,the arc voltage of the C4-PFN-CO₂ mixed gas is very close to SF₆ at 0.6 MPa,and voltage spikes also appear at the start of the arc.It means that the increase of pressure can significantly improve the energy dissipation rate of the mixed gas and the arc extinguishing performance.For arc time dispersion,the increase of pressure also reduces the dispersion,which significantly improves the arc stability during the current interruption process.

Key words: SF₆ alternative gases, C4-PFN-CO₂ mixed gas, disconnecting switch, arc extinguishing performance