交流电压下C4F7N/CO2混合气体中线性金属微粒放电特性研究

为了研究环保型气体C4F7N的绝缘性能,本文开展了绝缘子表面线性金属微粒在C4F7N/CO2混合气体下的放电特性实验并结合仿真和理论对实验结果进行了分析。研究结果表明,在0.1MPa气压条件下,C4F7N/CO2混合气体中,绝缘子表面附有金属微粒时,闪络电压会随金属微粒和接地电极之间距离的增加而先增大后减小。分析上述原因,线性金属微粒端部电晕放电产生的空间电荷削弱了空间电场的畸变程度；同时,C4F7N/CO2混合气体分解产生的CF3CN分子是一种高电气强度的物质,也会促使闪络电压升高。绝缘子倾角的变化对C4F7N/CO2混合气体闪络电压的影响要大于对SF6气体闪络电压的影响。绝缘子倾角为90度条件下,C4F7N/CO2混合气体下的闪络为SF6气体下闪络电压的0.96倍,两种气体绝缘性能相当。但C4F7N/CO2混合气体对不均匀电场的敏感性要高于SF6气体,电场不均匀系数由1变化到1.84时,C4F7N/CO2混合气体条件下闪络电压降低约26%。

Study on Discharge Characteristics of a Linear Metal Particle inC4F7N/CO2 Gas Mixture under AC Voltage

In order to study the insulation performance of environment-friendly gas , this paper studied the discharge characteristics of a linear metal particle on the insulator surface in the mixtures of C4F7N/CO2. The experiment results were analyzed by simulation and theory. The research show that the flashover voltage increases first and then decreases with the increase of the distance between the metal particle and the ground electrode, in the mixture of C4F7N/CO2 gas at 0.1 MPa. By analyzing the above reasons, the space charge generated by corona discharge at the end of linear metal particle weakens the distortion of space electric field. At the same time, the CF3CN molecule produced by the decomposition of C4F7N/CO2 mixture gas is a kind of material with high electrical strength, which can also increase the flashover voltage. The influence of insulator inclination on the flashover voltage of C4F7N/CO2 mixture gas is greater than that of SF6 gas. When the inclination angle of insulator is 90 degrees, the flashover voltage of C4F7N/CO2 gas mixture is 0.96 times of SF6 gas, the electric strength of the two gases is the same. However, the sensitivity of C4F7N/CO2 gas mixture to inhomogeneous electric field is higher than SF6 gas. When the inhomogeneity coefficient of electric field changes from 1 to 1.84, the flashover voltage of C4F7N/CO2 gas mixture decreases by about 26%.