The cables are more likely to deteriorate after several years of service in Shanghai,a city with a humid climate and abundant rainfall.Before assessing the aging status of those cables,it is critical to present effect...The cables are more likely to deteriorate after several years of service in Shanghai,a city with a humid climate and abundant rainfall.Before assessing the aging status of those cables,it is critical to present effective test parameters which are sensitive to the aging process under special field conditions.Therefore,we have performed water tree investigation,tensile test,and differential scanning calorimetry(DSC)test on hundreds of cable samples removed from service.A large number of typical bowtie water trees were found in cable insulation and the water tree content was proposed to characterize the degree of water treeing.Based on Arrhenius Equation and equivalent thermal history parameters estimated from DSC profiles,we also proposed a new parameter ln(t/τθ)to characterize the aging status of cable insulation,Where,t is treated duration andτθis the thermal life under treated temperature.The applicabilities of water tree content,tensile strength,and ln(t/τθ)are tested using the analysis of variance(ANOVA).Then we investigated the relationship between the tensile strength and the water tree content using regression analysis,and analyzed the relationship between ln(t/τθ)and the tensile strength.The results indicated that each of these parameters performs differently with cables which experienced different degrees of age related degradation,and can be used to identify the aging status of field aged cables.The tensile strength can reflect the water treeing condition of field aged cables very well as a commonly used functional parameter.Since ln(t/τθ)is strongly related to the tensile strength,it is an effective parameter to characterize the aging status of field aged cable insulation.Using this newly proposed parameter is more time saving because of the convenience in sampling.展开更多
交联聚乙烯电力电缆在长期的使用过程中不可避免会出现的一个问题就是电树枝化,在很大程度上影响了交联聚乙烯电力电缆的使用寿命。为了有效解决电树枝化的问题,需要对交联聚乙烯电力电缆在使用过程中的电树枝化规律进行探讨,对局部放...交联聚乙烯电力电缆在长期的使用过程中不可避免会出现的一个问题就是电树枝化,在很大程度上影响了交联聚乙烯电力电缆的使用寿命。为了有效解决电树枝化的问题,需要对交联聚乙烯电力电缆在使用过程中的电树枝化规律进行探讨,对局部放电特征进行分析。文章试验用的电缆型号为XLPE,在常温下进行工作频率在12~21 k V、温度在50~90℃下的电树枝化试验,对电树枝的形成过程和局部放电特征进行了探讨和分析。展开更多
基金Project supported by Special Fund of the National Priority Basic Research of China(2014CB239503)National Natural Science Foundation of China(51277117)Shanghai Science and Technology Commission(11DZ2283000)
文摘The cables are more likely to deteriorate after several years of service in Shanghai,a city with a humid climate and abundant rainfall.Before assessing the aging status of those cables,it is critical to present effective test parameters which are sensitive to the aging process under special field conditions.Therefore,we have performed water tree investigation,tensile test,and differential scanning calorimetry(DSC)test on hundreds of cable samples removed from service.A large number of typical bowtie water trees were found in cable insulation and the water tree content was proposed to characterize the degree of water treeing.Based on Arrhenius Equation and equivalent thermal history parameters estimated from DSC profiles,we also proposed a new parameter ln(t/τθ)to characterize the aging status of cable insulation,Where,t is treated duration andτθis the thermal life under treated temperature.The applicabilities of water tree content,tensile strength,and ln(t/τθ)are tested using the analysis of variance(ANOVA).Then we investigated the relationship between the tensile strength and the water tree content using regression analysis,and analyzed the relationship between ln(t/τθ)and the tensile strength.The results indicated that each of these parameters performs differently with cables which experienced different degrees of age related degradation,and can be used to identify the aging status of field aged cables.The tensile strength can reflect the water treeing condition of field aged cables very well as a commonly used functional parameter.Since ln(t/τθ)is strongly related to the tensile strength,it is an effective parameter to characterize the aging status of field aged cable insulation.Using this newly proposed parameter is more time saving because of the convenience in sampling.
文摘交联聚乙烯电力电缆在长期的使用过程中不可避免会出现的一个问题就是电树枝化,在很大程度上影响了交联聚乙烯电力电缆的使用寿命。为了有效解决电树枝化的问题,需要对交联聚乙烯电力电缆在使用过程中的电树枝化规律进行探讨,对局部放电特征进行分析。文章试验用的电缆型号为XLPE,在常温下进行工作频率在12~21 k V、温度在50~90℃下的电树枝化试验,对电树枝的形成过程和局部放电特征进行了探讨和分析。
