ZnO避雷器电阻片上电压承担率优化方法

Optimizing method for voltage commitment rate of ZnO surge arrester

氧化锌避雷器是过电压防护的重要电气设备,但非线性电阻片上电压分布不均匀将导致局部电阻片的运行荷电率升高,进而引发电阻片发生热崩溃.为此,通过定义每个氧化锌电阻片上的电压承担率,研究电阻片相对介电常数对电压承担率的影响,并给出一种通过改变上、下节氧化锌电阻片的相对介电常数来改善电阻片电压承担率的方法,采用COMSOL软件对330 kV变电站的氧化锌避雷器进行三维立体建模,研究氧化锌避雷器场强分布情况.结果表明,氧化锌避雷器上节采用大电容(相对介电常数为800),下节采用小电容(相对介电常数为650)时,电压分布不均匀系数得到很大的改善,从而优化了氧化锌避雷器的结构.

Zinc oxide arrester is an important electrical equipment for over-voltage protection,but the non-uniform distribution of voltage on the non-linear varistors will result in the increase of the operating charge rate of partial varistors,which in turn will lead to the thermal collapse of these varistors.For this purpose,by defining the voltage-bearing rate on each Zinc oxide resistor,the effect of the relative dielectric constant of the resistor on the voltage-bearing rate is studied,and a method to improve the voltage-bearing rate on the resistor by changing the relative dielectric constant of the upper and lower sections of the Zinc oxide resistor is proposed,the three-dimensional model of Zinc oxide arrester in330kV substation is built by COMSOL software,and the field intensity distribution of Zinc oxide arresters is studied.The results show that the non-uniform coefficient of voltage distribution is greatly improved when large capacitance(relative dielectric constant800)is used in the upper section and small capacitance(relative dielectric constant650)is used in the lower section.Thus the structure of Zinc oxide arresters is optimized.