交直流复合电压下纳米Al_(2)O_(3)改性绝缘纸板介电与电荷特性研究  

Study on Dielectric and Charge Properties of Nano-Al2O3 Modified Paperboard Under AC-DC Composite Voltage

作　　者：黄峻峰 秋向飞 刘志华[2] 李斯盟 HUANG Junfeng;QIU Xiangfei;LIU Zhihua;LI Simeng(State Grid Shaanxi Electric Power Co.,Ltd.,Xi’an 710048,China;College of Electrical Engineering,Xi’an Jiaotong University,Xi’an 710049,China)

机构地区：[1]国网陕西省电力有限公司,西安710048 [2]西安交通大学电气工程学院,西安710049

出　　处：《高压电器》2022年第12期138-146,共9页High Voltage Apparatus

基　　金：国家自然科学基金(52007148)。

摘　　要：换流变压器油纸绝缘系统长期工作于复杂的电应力下,容易出现绝缘问题。通过纳米改性改变纸板的介电与电荷特性,进而提高纸板在复合电压下的绝缘性能是一种可行的方法。针对上述问题,研究了不同掺杂浓度下纳米Al_(2)O_(3)改性绝缘纸板的介电常数、介质损耗、体积电阻率与击穿场强,随后对改性纸板在交直流复合电压下的空间电荷特性进行了探究与分析。研究表明,纳米Al_(2)O_(3)的掺杂可有效降低绝缘纸板的介电常数和介电损耗,并且提高绝缘纸板的电阻率。在交流、直流、交直流复合电压下,3%掺杂浓度改性纸板的击穿场强最高。纳米改性抑制了电荷的注入与积聚,从而改善纸板电场分布,使得复合电压中直流分量占比越大,纳米颗粒的掺杂对绝缘纸板击穿强度的提高效果越明显。该工作对换流变压器绝缘优化及改性纸板在复杂电场下的应用推广具有重要意义。The oil-paper insulation system of converter transformer works under complex electrical stress for a long time,which is prone to insulation problems.It is a feasible method to change the dielectric and charge characteristics of paperboard through nano modification so to improve insulation performance of paperboard under composite volt-age.In view of above problems,the relative permittivity,dielectric loss,volume resistivity and breakdown field strength of nano-Al_(2)O_(3) at different doping concentration are studied firstly.Then,the space charge characteristics of the modified paperboard under composite voltage are explored and analyzed.The study shows that the doping of nano-Al_(2)O_(3) can effectively reduce the relative permittivity and dielectric loss of the insulating paperboard,and improve re-sistivity of insulating paperboard.Under the AC,DC and AC-DC composite voltage,the breakdown field strength of paperboard with 3%doping concentration is the highest.Nano modification inhibits the charge injection and accumu-lation so as to improve the electric field distribution of the paperboard.The larger the proportion of DC component in composite voltage,the more obvious the effect of nano particle doping on the improvement of breakdown strength of the insulating paperboard.This work is of great significance to the insulation optimization of converter transformer and the application and promotion of modified paperboard under complex electric fields.

关 键 词：油纸绝缘 纳米改性 交直流复合电压 空间电荷 

分 类 号：TM721.1[电气工程—电力系统及自动化] TM41