The nonlinear I-V characteristics of ZnO varistors arise from the grain boundary barrier structure. Modification research has focused on formula optimization

preparation process improvement

and conduction mechanism exploration. With the advancement of "dual-carbon" goals and the construction of new energy projects like ultra-high voltage transmission and offshore wind power

the power system's demands for overvoltage protection levels and equipment lightweighting have significantly increased

presenting new opportunities and challenges for ZnO varistor modification research. Currently

ZnO varistor modification primarily follows two technical routes: one is to optimize the traditional mechanical powder mixing process; however

due to poor additive dispersion and difficulties in regulating grain boundary defects

performance improvements are gradually slowing down. The other is to perform new powder design based on coating technology

which constructs a surface functional layer to significantly improve additive dispersion and interface characteristics

offering a new way to overcome traditional process limitations. This paper systematically reviews the latest research achievements in mechanical powder mixing processes

and summarizes the current key research directions. This paper also reviews the latest exploratory results achieved in enhancing the performance of ZnO varistor through coating technology

and puts forward the future development trend

aiming to provide theoretical support and technical guidance for high-performance ZnO varistors.