CF_3I/N_2混合气体在不同电场下的工频击穿特性试验研究

Experimental Research of CF_3I/N_2 Gas Mixtures on Power Frequency Breakdown Performances Under Different Electric Field

CF_3I及其混合气体作为SF_6应用于电气设备的潜在替代物被广泛关注,该文从不同电场下工频击穿性能的角度探讨CF_3I/N_2替代SF_6气体的可行性。通过工频击穿试验探究气压、混合比、电场利用系数3种因素对CF_3I/N_2工频击穿电压的影响,并与相同条件下的SF_6及SF_6/N_2进行对比分析,使用协同效应指数C值判定混合气体协同效应类型并定量分析协同效应强弱。结果表明,CF_3I/N_2在不同电场、不同混合比下的工频击穿电压随气压均呈线性增长,随着电场利用系数的增加,其工频击穿电压随气压增长的线性增长率逐渐提高;纯CF_3I对电场的敏感度尤其高。N_2的加入,改善了CF_3I对电场的敏感度;极不均匀电场下,CF_3I/N_2混合气体在0.15MPa及以上气压呈正协同效应,协同效应明显程度整体优于SF_6/N_2混合气体。稍不均匀电场和准均匀电场下,CF_3I/N_2呈现协同效应,气压越高,协同效应越明显;混合比为30%,气压为0.3MPa的CF_3I/N_2可以替代纯SF_6应用于气体绝缘输电线路和气体绝缘开关柜等电气设备中。

As a potential substitute of SF_6 applied in electric equipment, CF_3I and its gas mixtures have been widely noted. The paper was about the possibility of CF_3I/N_2 substituting SF_6 gas from breakdown performances under different electric fields. The effects of pressure, mixture ratio and electric field utilization coefficient on CF_3I/N_2 breakdown voltage were investigated through power frequency breakdown tests. The results were compared with SF6 and SF6/N2 in the same condition. Synergy index C was used to define synergistic effect type of gas mixtures and analyze strength of synergistic effect quantitatively. The results show that power frequency breakdown voltage of CF3I/N2 increases linearly with pressure under different electric fields and mixture ratios. With the growth of electric field utilization coefficient, its power frequency breakdown voltage increases gradually with pressure＇s linear growth rate. Pure CF3 I is extremely sensitive to electric field. Adding N2 contributes to improving sensibility of CF3 I towards electric field; under extremely nonuniform electric field, CF3I/N2 gas mixtures have positive synergistic effect which is better than SF6/N2 gas mixtures when the pressure is equal or higher than 0.15 MPa. Under slightly nonuniform and quasi-uniform electric fields, CF3I/N2 has synergistic effect. The higher the pressure is, the more obvious the synergistic effect is; When the mixture ratio is 30%, CF3I/N2 of 0.3MPa can be used in gas insulation line（GIL）, cubicle gas insulation switchgear（C-GIS） and other electric equipment to substitute SF_6.