Abstract：A new method for destruction-free lifetime evaluation on cross-linked polyethylene cables is studied in this paper. The third order exponential decay fitting is utilized to process measured isothermal relaxation current (IRC) data. The current I could be calculated by subtracting the steady direct current component from measured current, and then the relationship between I*t and log (t) is obtained. Consequently, the weight of each kind of depolarization current component is obtained and the aging status could be evaluated by means of analysis and comparison on the peak-value location. The aging factor (A) is introduced for the convenience of classifying the aging level of cables. The experiment results show that although there are some errors, this new method can effectively evaluate the aging status of cables. Because of the influence of sampling and the manufacturing technology, to some extent, the factor A calculated from these experiments is bigger than those reported by foreign scholars.
王雅群, 尹毅, 李旭光, 蔡川. 等温松弛电流用于10kV XLPE电缆寿命评估的方法[J]. 电工技术学报, 2009, 24(9): 33-37.
Wang Yaqun Yin Yi Li Xuguang Cai Chuan. The Method of Lifetime Evaluation on 10kV XLPE Cables by Isothermal Relaxation Current
. Transactions of China Electrotechnical Society, 2009, 24(9): 33-37.
[1] 李明华, 董明, 严璋. 一种新的绝缘测试方法——回复电压法[J]. 高电压技术, 2002, 28(8)：43-45. [2] Chen Jiqun W S. Method of estimating the remaining life of the 10kV XLPE cable operated 10 years[C]. The 6th International Conference on Properties and Applications of Dielectric Materials, Xi'an China, 2000: 204-208. [3] Beigert M, Kranz H G. Destruction free ageing diagnosis of power cable insulation using the isothermal relaxation current analysis[C]. Conference Record of the 1994 IEEE International Symposium on Electrical Insulation, Pittsburgh, Pennsylvania, 1994:17-21. [4] Simmons J G, Tam M C. Theory of isothermal current and the direct determination of trap parameters in semiconductors and insulators containing arbitrary trap distributions[J]. Physical Review B, 1973, 7: 3706- 3713. [5] 赵文彬, 张冠军, 严璋. 复合材料的陷阱参数对其在真空中高压脉冲下沿面闪络特性的影响[J]. 中国电机工程学报, 2007, 27(9): 11-17. [6] Kranz H G, Steinbrink D F M. IRC-analysis: A new test procedure for laid XLPE-cables[C]. 10th International Symposium on high Voltage Engineering, Montreal, 1997: 207-210. [7] Oyegoke B S, Foottit F, Birtwhistle D, et al. Condition assessment of XLPE insulated cables using isothermal relaxation current technique[C]. IEEE Power Engineering Society General Meeting, 2006: 18-22. [8] Birkner P. Field experience with a condition-based maintenance program of 20kV XLPE distribution system using IRC-analysis[J]. IEEE Transactions on Power Delivery, 2004, 19(1): 3-8.
2009, Vol. 24 
