摘要
为了获得性能更为稳定的ZnO压敏电阻,研究了含有Ga掺杂的ZnO压敏电阻的稳定特性,对所获得的实验样品的微观结构和电气特性进行了电子显微镜扫描测试、电压-电流非线性特性测试、电容-电压特性测试、X-射线衍射谱测试、能谱扫描测试、介质损耗测试及交流加速老化测试.实验结果表明,随着Ga掺杂量的进一步增加,Ga离子占据了ZnO晶格上的空位,增加了界面态密度,提高了肖特基势垒高度,一方面降低了ZnO压敏电阻的泄漏电流密度,另一方面抑制了耗尽层中自由电子的迁移,提高了ZnO压敏电阻在高荷电率环境下的稳定特性.Al离子固溶到ZnO晶格当中,产生大量的自由电子,降低了ZnO晶粒的电阻率,从而有效降低了ZnO压敏电阻在通过大电流时的残压比.当Ga的掺杂摩尔分数达到0.6%时,泄漏电流密度为0.84μA/cm^(2),残压比为1.97,非线性系数为66,其肖特基势垒高度为1.81 eV.在115℃环境下,对试验样品施加87%E1 mA,89%E1 mA和91%E1 mA的交流加速老化电压,老化时间为1000 h,老化系数分别为0.394,0.437和0.550.此研究将有助于进一步提高ZnO避雷器的保护水平,实现深度限制电网过电压,提高电力系统的安全稳定性.
The insulation level of power equipment in power system is based on the overvoltage protection level of metal oxide arrester represented by zinc oxide valve blade.Owing to its superior nonlinear voltage current characteristics and surge energy absorption capacity,ZnO varistor is widely used as the core component of power system arrester.The electrical characteristics of ZnO varistors are determined by their complex microstructures and grain boundary characteristics.Therefore,to further improve the insulation level of power grid equipment,doping is required to further improve the grain boundary characteristics of ZnO varistors.In order to obtain more stable ZnO varistors,the stability characteristics of Ga doped ZnO varistors are investigated.The microstructural and electrical characteristics of the obtained experimental samples are tested by scanning electron microscope,voltage current nonlinear characteristics,capacitance voltage characteristics,X-ray diffraction spectrum,energy spectrum scanning,dielectric loss,and AC acceleration aging.The experimental results show that with the further increase of gallium doping,gallium ions occupy the vacancies on the zinc oxide lattice,increasing the interface state density,and improving the Schottky barrier height.On the one hand,the leakage current density of ZnO varistor is reduced,on the other hand,the migration of free electrons in the depletion layer is suppressed,and the stability of ZnO varistor in the high charge rate environment is improved.Aluminum ions are dissolved into the ZnO lattice to generate a large number of free electrons,thereby reducing the resistivity of ZnO grains,which can effectively reduce the residual voltage ratio of ZnO varistor when large current passes through it.When the doping amount of Ga reaches 0.6%,the leakage current is 0.84μA/cm^(2),the residual voltage ratio is 1.97,the nonlinear coefficient is 66,and the Schottky barrier height is 1.81 eV.At 115℃,AC accelerated aging voltages of 87%E_(1) mA,89% E_(1) mA and 91% E_(1) mA are applied to the test sample separately.The aging time is 1000 h,and the aging coefficients are 0.394,0.437 and 0.550 separately.This research will help to further improve the protection level of zinc oxide surge arresters,achieving the deep limitation of grid overvoltage,and improving the security and stability of power systems.
作者
刘冬季
马圆圆
何金柏
王昊
周远翔
孙冠岳
赵洪峰
Liu Dong-Ji;Ma Yuan-Yuan;He Jin-Bai;Wang Hao;Zhou Yuan-Xiang;Sun Guan-Yue;Zhao Hong-Feng(Ningdong Power Supply Company of State Grid,Ningxia Electric Power Co.,Ltd,Lingwu 751400,China;School of Electrical Engineering,Shandong University,Jinan 250061,China;State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment,Department of Electrical Engineering,Tsinghua University,Beijing 100084,China;School of Energy and Mechanical Engineering,Dezhou University,Dezhou 253023,China;Wind and Solar Energy Storage Branch,State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment,School of Electrical Engineering,Xinjiang University,Urumqi 830046,China)
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2023年第6期237-245,共9页
Acta Physica Sinica
基金
国家自然科学基金(批准号:51777162)资助的课题.
作者简介
通信作者:刘冬季,E-mail:liudj19@126.com。
