高电压技术2018，Vol.44Issue(5)：1706-1714,9.DOI:10.13336/j.1003-6520.hve.20180430041
全尺寸空间电荷测量在水中老化电缆状态评估中的应用
Application of Full-size Space Charge Measurement in Condition Assessment of Cables Aged in Water
摘要
Abstract
Water tree aging is a serious threat to the operational reliability of cables, so the effective condition assessment technology of cable insulation has important research value. Selecting unaged cables and cables aged in water as research objects, we detected the aging conditions by isothermal relaxation current (IRC) method. And then we applied the full-size space charge measurement to study the space charge distribution of cables. The results show that, after aging in water, the depolarization current curves move up, aging factors become higher, and deep traps increase significantly. During the polarization process, space charge accumulates increasingly and under high electric fields, and homocharge is injected near the anode. During the depolarization process, shallow trap charge gradually disappears, but homocharge in deep traps still resides forming a distinctive positive charge peak. At the same time, after aging in water, the mean volume density of space charge in cables during the depolarization process increases. The analysis indicates that, after water aging treatment, the water intrusion to the cable insulation from the external environment may lead to the formation of outer water trees in outer semi-conductive layer. Homocharge is injected from the tip of water trees initiated from the outer semi-conductive layer, situating in deep traps, and it agrees with the phenomenon that the depolarization current, trap density and aging factor of water-aged cables measured with the IRC method are higher than those in unaged cables. The result proves that the IRC method is effective and that full-size space charge measurement can assess the local insulation state of cables, which can be used for the diagnosis and check of high risk point of failure in cables.关键词
全尺寸/空间电荷/电缆/老化评估/等温松弛电流/水树枝Key words
full-size/space charge/cable/aging assessment/isothermal relaxation current/water tree引用本文复制引用
钱恺羽,张昱,刘德远,吴建东,尹毅..全尺寸空间电荷测量在水中老化电缆状态评估中的应用[J].高电压技术,2018,44(5):1706-1714,9.基金项目
国家自然科学基金(51477095) （51477095）
中国博士后科学基金 (2015M570364).Project supported by National Natural Science Foundation of China (51477095), China Postdoctoral Science Foundation (2015M570364). （2015M570364）
