SF6断路器弧触头关合侵蚀特性研究

Study on Corrosion Characteristics of Arc Contact of SF6 Circuit Breaker in Switching Operation

SF6断路器关合电容器组过程中会产生高频高幅值的涌流,在预击穿电弧烧蚀和弧后机械磨损的双重作用下,SF6断路器弧触头的关合侵蚀加剧而影响其使用寿命。为此,文中对SF6断路器弧触头关合侵蚀特性进行了深入研究。基于等电荷量法对弧触头进行燃弧实验和关合涌流实验,获得了触头侵蚀形貌、预击穿燃弧时间、接触电阻和质量损失。根据弧触头运行条件建立仿真模型,分析了动、静弧触头的温度场变化及接触碰撞过程。结果表明,弧后机械磨损是弧触头关合侵蚀的重要组成部分,随着涌流峰值的增大,机械磨损所占比例增大,当涌流峰值为15 kA时,由机械磨损产生的质量损失占总质量损失的32.25%。在预击穿电弧的烧蚀下,触头材料性能发生变化,触头表面变得粗糙;弧触头接触后,由于材料物性参数的变化,导致触头的机械磨损加剧;断路器下一次关合时,由于之前的侵蚀作用,使触头间隙更容易击穿,烧蚀时间变长,进而使机械磨损变得更加严重。

High frequency and high amplitude inrush current will be generated in the process of switching capacitor bank of SF6 circuit breaker.Under the effect of both pre⁃breakdown arc ablation and post⁃arc mechanical wear,the switching erosion of the arc contact of SF6 circuit breaker will aggravate and affect its service life.Therefore,the switching erosion characteristics of arc contact of SF6 circuit breaker are studied in depth in this paper.Arcing experi⁃ments and making inrush current experiments are performed based on the equal charge method,and the contact ero⁃sion morphology,pre⁃breakdown arcing time,contact resistance and mass loss are obtained.The simulation model is set up according to the operating conditions of the arc contact,and the temperature field variation and contact colli⁃sion process of the moving and stationary arc contacts are analyzed.The results show that the post⁃arc mechanical wear is an important part of the making erosion of the arc contact.With the increase of the peak value of the inrush current,the proportion of mechanical wear increases.When the inrush current is 15 kA,the mass loss due to mechan⁃ical wear accounts for 32.25%of the total mass loss.Under the ablation of pre⁃breakdown arc,the performance of con⁃tact material changes,and the contact surface becomes rough.After contact of the arcing contact,the mechanical wear of the contact is aggravated due to the change of material physical parameters.In case of next making operation of circuit breaker,the prior erosion makes the contact gap easier to breakdown and the ablation time becomes longer,