交直流复合电压下直流预压诱发老化油纸绝缘沿面闪络现象  

Surface Flashover Phenomenon of Aged Oil-paper Insulation Induced by DC Voltage Preloading Under the Combined AC-DC Voltage

作　　者：金福宝[1] 周远翔[2] JIN Fubao;ZHOU Yuanxiang(School of Energy and Electrical Engineering,Qinghai University,Xining 810016,China;State Key Laboratory of Control and Simulation of Power Systems and Generation Equipments,Department of Electrical Engineering,Tsinghua University,Beijing 100084,China)

机构地区：[1]青海大学能源与电气工程学院,西宁810016 [2]清华大学电机系电力系统及发电设备控制和仿真国家重点实验室,北京100084

出　　处：《高电压技术》2023年第10期4421-4428,共8页High Voltage Engineering

基　　金：国家自然科学基金(51865049)。

摘　　要：长期运行换流变压器中老化油纸绝缘界面处的沿面闪络现象将危及设备和电网的安全。在研究交直流复合电压作用下老化油纸绝缘的闪络特性时,发现老化油纸试样在较高幅值直流电压预压的过程中突然出现沿绝缘纸板表面闪络的现象。为此针对直流电压分量和老化程度对交直流复合电压下油纸绝缘的闪络特性影响进行了研究,并基于电子触发极化松弛理论,结合空间电荷特性、老化油纸绝缘的表面形貌、老化产物对产生该现象的机理进行了探究。研究认为诱发直接闪络的主要是由于在直流电场作用下老化后绝缘纸板中空间电荷总量急剧增加,同时老化绝缘纸板表面形貌畸变电场,弱极性及酸性老化产物等因素的综合影响致使载流子迁移运动加快,进而加剧了对老化油纸绝缘空间电荷平衡状态的扰动和破坏,最终引发直流预压过程中沿绝缘纸板表面的闪络现象。The surface flashover phenomenon at the interface of aged oil-paper insulation in the long-term operation of the converter transformer will endanger the safety of equipment.When studying the surface flashover characteristics of aged oil-paper insulation under the combined AC and DC voltages,it is found that flashover may suddenly appear in the aged oil-paper samples along the surface of insulating paperboard during the preloading process of higher amplitude DC voltage.Therefore,we studied the effects of DC voltage component and aging degree on the flashover characteristics of oil-paper insulation under combined AC and DC voltages.Based on the theory of electron-triggered polarization relaxation,combined with space charge characteristics,surface morphology of aged oil-paper,and aging products,the mechanism of this phenomenon was explored.It is believed that the main reason for the direct flashover is that the total amount of space charge in the insulating paper increases sharply after aging under the DC electric field.At the same time,due to the comprehensive influence of factors such as surface morphology of aged insulating paper distorts electric field,weak polarity and acidic aging products,the migration of carriers is accelerated.This further aggravate the disturbance and destruction of the space charge balance state of the aged oil-paper insulation,and finally lead to the flashover phenomenon along the surface of the insulating paper during the DC preloading process.

关 键 词：油纸绝缘 老化 交直流复合电压 沿面放电 直流预压 

分 类 号：TM855[电气工程—高电压与绝缘技术] TM721.1