冷却介质对低密度聚乙烯空间电荷输运特性的影响  

Influence of Cooling Medium on Space Charge Transport Property of LDPE

作　　者：李剑[1] 沈健[1] 杨丽君[1] 章华中[1] 赵玉顺[1] 

机构地区：[1]重庆大学输配电装备及系统安全与新技术国家重点实验室,重庆400030

出　　处：《高电压技术》2010年第11期2629-2633,共5页High Voltage Engineering

基　　金：国家自然科学基金(50807054)~~

摘　　要：低密度聚乙烯是高压电力电缆的主要绝缘材料,空间电荷被认为是影响电力电缆绝缘安全可靠性的关键因素之一。为此,选用冰水、空气和硅油3种不同冷却方式对聚乙烯试品进行淬火处理,采用电声脉冲法测量系统对聚乙烯试品中空间电荷的消散特性进行了测试,并结合阶梯式升压试验测定空间电荷阈值场强,根据空间电荷限制电流理论推导出总电荷量与电荷迁移率,采用差示扫描量热法分析了试样的结晶度和晶粒尺寸均匀性。试验与分析结果表明:硅油冷却聚乙烯电荷视在迁移率大于冰水、空气冷却试样;3种试样中,硅油冷却聚乙烯结晶度较高,晶粒尺寸分布较均匀,阈值场强较高,而冰水冷却聚乙烯结晶度、晶粒分布均匀性与阈值场强较低。The space charge is considered as the key factor restricting the safe running of the power cable.The low density polyethylene（LDPE） samples used for space charge experiments were obtained by cooling in ice water,air,and silicone oil.The dissipation characteristics of space charges were investigated based on the space charge testing system of pulse electro-acoustic approach.The threshold stress was measured using the voltage ramp test.Based on the pushover formula of space charge limited current theories,the total charge and apparent mobility of charge were obtained.Crystallinity and crystal grain size uniformity of LDPE samples were analyzed through differential scanning calorimetry.Experimental and analysis results show that the charge apparent mobility in LDPE sample cooled in silicone oil were higher than those in LDPE samples cooled both in ice water and in air.Among the three types of LDPE samples,the LDPE samples cooled in silicon oil have a greater degree of crystallinity,the size of crystal grains is more uniform,and the threshold stress is higher.The LDPE samples cooled in ice water have a lower degree of crystallinity,the finer uniform size of crystal grains,the lower threshold stress.

关 键 词：低密度聚乙烯(LDPE) 电力电缆 冷却介质 空间电荷 输运特性 结晶状态 

分 类 号：TM211[一般工业技术—材料科学与工程]