高电场下ZnS:Cu 复合涂层的电致发光机理

Electroluminescence Mechanism of ZnS:Cu Composite Coatings Under High-electric-field

输变电设备安装运行过程中不可避免产生各种绝缘缺陷,将电致发光材料引入绝缘系统,能够直观显示高电场区,进而实现绝缘缺陷的自检测。该文针对ZnS:Cu复合涂层在高电场下的电致发光机制进行研究,利用棒–板结构电极在变压器油与空气中的不同特点,通过发光分布、放电电流与表面电荷等特性的观测,分别考察在无放电和有放电情况下的电致发光特征。结果表明,ZnS:Cu复合涂层的电致发光来源于无放电时的电荷极化发光与高电场下的气体放电诱导发光,其中电荷极化发光分布与电场强度密切相关;放电起始后,气体放电沉积在涂层表面的正负电荷向ZnS:Cu迁移形成激子,进而以辐射跃迁的方式产生发光。实验获得了ZnS:Cu复合涂层的基本发光机制,对在电场分布定性表征与绝缘缺陷自诊断中的应用具有指导意义。

Various kinds of insulation defects are inevitably generated during the assembling and operation of electric transmission and transformation equipment.electroluminescence materials could be introduced into insulation systems to visually display the high-electric-field regions,which realizes the self-detection of insulation defects.In this work,the electroluminescence mechanism of ZnS:Cu composite coatings under high-electric-field is investigated.By measuring the luminance distribution,discharge current and surface charge distribution of rod-plane electrode in transformer oil and air,the electroluminescence properties without and with discharges are explored,respectively.The results indicate that the electroluminescence of ZnS:Cu composite coating comes from charge polarization luminescence without discharge and gas discharge induced luminescence under high-electric-field.The distribution of charge polarization luminescence is closely correlated to the electric field.When the discharge is initiated,the generated positive and negative charges are deposited on the coatings and migrate to ZnS:Cu particles,which form the excitons and thereby produce luminescence by the radiative transition.The basic electroluminescence mechanism of ZnS:Cu composite coatings is derived by experimental results,which could guide its application in qualitative characterization of electric filed and self-diagnosis of insulation defects.