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| The Method of Lifetime Evaluation on 10kV XLPE Cables by Isothermal Relaxation Current
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| Wang Yaqun Yin Yi Li Xuguang Cai Chuan |
| Shanghai Jiaotong University Shanghai 200030 China |
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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.
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Received: 23 June 2008
Published: 17 February 2014
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2009, Vol. 24 
