AC ageing characteristics of Co-doped ZnO varistors  

作　　者：TU YouPing WANG Qian HE Jie LI Xiao DING LiJian 

机构地区：[1]Beijing Key Laboratory of High Voltage & EMC(North China Electric Power University) [2]School of Automation and Information Engineering,Xi'an University of Technology [3]China Electric Power Research Institute

出　　处：《Science China(Technological Sciences)》2013年第6期1354-1360,共7页中国科学（技术科学英文版）

基　　金：supported by the National Natural Science Foundation of China (Grant No. 50577021);the Doctoral Program Foundation of Institutions of Higher Education of China (Grant No. 200800790004)

摘　　要：As the key protection device in the power system, the ageing characteristics of ZnO varistor can directly affect the safe operation of power system. In order to study the influence of Co2O3 content on the electrical properties of ZnO varistors, thermally stimulated current (TSC) characteristics test, capacitance-voltage (C-V) characteristics test, scanning electron microscope (SEM) test, voltage-current (V-I) test were carried out on ZnO varistors before and after AC ageing tests. The results show that the mean grain size decreases while the varistor voltage increases as the Co2O3 content increases, the barrier height and the defects of ZnO varistors increase with the increase of Co2O3 content, and the barrier height decreases at a certain degree after AC ageing test. As the Co2+ ion radius is close to that of Zn2+ ion, it is easy for Co2+ ions to enter into ZnO lattice during sintering process, which is account for the increase of zinc interstitial of ZnO varistors. When the Co2O3 content exceeds a certain range, the AC degradation degree of ZnO varistors will become much more serious. From the experimental results, ZnO varistors doped with 1.0 mol% Co2 O3 exhibit a better performance.

关 键 词：ZnO varistors Co2O3 AC ageing thermally stimulated current （TSC） Schottky barrier 

分 类 号：TM54[电气工程—电器]