空间电荷对油纸绝缘击穿和沿面闪络的影响  

Effects of Space Charge on Breakdown and Creeping Discharge of Oil-Paper Insulation

作　　者：周远翔[1] 孙清华[1] 李光范[2] 王云杉[1] 姜鑫鑫[1] 仇宇舟[2] 李金忠[2] 王宁华[2] 

机构地区：[1]清华大学电机系电力系统国家重点实验室,北京100084 [2]中国电力科学研究院,北京100192

出　　处：《电工技术学报》2011年第2期27-33,共7页Transactions of China Electrotechnical Society

基　　金：教育部新世纪优秀人才支持计划(NCET-04-0095);教育部博士点基金(200800030040)资助项目;国家自然科学基金(50438070)

摘　　要：换流变压器是直流输电工程的核心设备之一,其结构和工作状况比传统交流变压器更为复杂,需要对其绝缘系统进行更深入的研究。本文针对换流变压器的特点,设计了相应的试验装置,对油纸绝缘中的体击穿和沿面闪络进行了试验研究。本文实现了变压器油纸绝缘空间电荷的测量,根据空间电荷的实测结果对油纸绝缘系统中极性反转现象进行了探讨,对直流电压下油纸绝缘中积聚的空间电荷畸变电场导致油纸绝缘的直流击穿特性发生的变化规律进行了研究。对油纸绝缘进行的沿面闪络试验表明,空间电荷的存在同样会影响油纸绝缘的沿面闪络。根据对上述试验结果进行讨论,本文认为传统交流变压器的设计理论、经验已不能满足换流变压器的要求,在换流变压器设计和制造中应给与空间电荷问题足够的关注,尤其是在空间电荷的消散特性方面有必要进一步开展深入的研究,为解决直流输电系统的换流变压器等相关设备在极性反转过程中存在的极性效应带来的绝缘问题提供试验和理论依据。As one of the most important apparatus used in high voltage direct current（HVDC） transmission system,converter transformer has complex structures and operates in a cruel environment.Therefore,more knowledge of the behavior of insulating systems is required.In this paper,experiments are designed according to the operating state of converter transformers,based on which the progress of breakdown and creeping discharge of oil-paper insulation are experimentally studied.Space charge accumulated in oil-paper insulation system is successfully measured.Polarity reversal effects in oil-paper insulation systems are demonstrated by the space charge testing results.In other words,space charge accumulated under the dc electrical stress showed influences on the breakdown of oil-paper insulation are experimentally confirmed.Moreover,the experiments show that space charge could also affect the creeping discharge of oil-paper insulation significantly.Based on these results,it is put forward that traditional transformer design rules may not be suitable for converter transformers.More attentions should be paid on space charge effects in the design and manufacture of converter transformers.Among these effects,the dispersing processes of space charge in oil-paper insulation are stressed to solve the insulation problem induced by polarity reversal in HVDC equipment.

关 键 词：换流变压器 油纸绝缘 体击穿 沿面闪络 空间电荷 

分 类 号：TM21[一般工业技术—材料科学与工程]