高频谐波电压对冷缩电缆终端的电场及温度影响研究  

Influences of High Frequency Harmonic Voltage on Electric Field and Temperature at Medium Voltage Cable Termination

作　　者：文春雷 刘建军[1] 詹宏[1] 张宇[1] 魏燕[1] 周凯[2] 

机构地区：[1]重庆市电力公司城区供电局,重庆400013 [2]四川大学电气信息学院,成都610065

出　　处：《高压电器》2011年第8期28-32,共5页High Voltage Apparatus

摘　　要：中压冷缩电缆终端可能会遭受到高频谐波电压的持续作用而使其绝缘迅速失效,其失效原因主要和高频电压下的电场和温度有关。笔者研究了高频谐波电压对35 kV电缆终端温度和电场的影响规律及机理,阐明了热点和电场分布之间的联系。通过高频谐波电压的电热老化试验装置,对两种不同类型的冷缩电缆终端(应力均匀型和几何型),施加不同频率的电压。通过红外热成像仪分析了不同的频率、幅值对电缆终端表面温度分布的影响。发现随着频率的增加,应力均匀型终端在局部地方形成明显的热点,随着频率增加,热点温度进一步升高,而几何型终端则温度变化不明显。通过有限元分析发现,应力均匀型终端的热点位置正好和电场的集中点相对应,随着频率增加,电缆阻性发热量增加,而几何型终端的电场较小,阻性发热不明显。该研究对于开发耐高频电压的冷缩终端具有一定的意义。Medium voltage cable terminations may soon lose their insulation because of the continuing action of high frequency harmonic voltage. The insulation breakdown depends on the electric field and temperature under high frequency voltage. In this paper, the effects of high frequency harmonic voltage on temperature and electric field of 35 kV cable terminations are investigated to understand the relationships between hot spot and electric field distribution. A high frequency and high voltage generator is applied to two types of cable terminations （stress grading type and geometric type）. By means of the thermal images, distribution of temperature is analyzed under different voltage frequency and amplitude of voltages. With the increase in voltage frequency and amplitude, temperature of hot spot rises for stress grading termination, whereas the temperature change is not obvious for geometric termination. The location of the hot spot is related to the maximum value of electric field strength for stress grading termination. The research may facilitate the development of new type cable terminations with high frequency resistance.

关 键 词：中压电缆 终端绝缘 高频电压 阻性发热 表面温升 

分 类 号：TM83[电气工程—高电压与绝缘技术]