高压直流电缆系统安全裕度试验研究

Thickness experimental on safety margin of HVDC cable system

掌握高压直流电缆系统的安全裕度是保证电缆线路长期安全运行的前提条件。为获取高压直流电缆系统的最高使用电压,文中测试了电缆绝缘和附件绝缘的电导率,得出了电导率对温度和电场强度的依赖关系,并求出了电导率表达式。以±80 kV高压直流电缆系统为研究对象,提出了电缆系统安全裕度试验方法,采用逐级加压的方式测试了电缆系统在最高运行温度90℃下的击穿电压。根据电缆绝缘和附件绝缘的电导率计算了电缆系统击穿时的电场分布,通过对比电缆系统击穿时的电场强度与长期运行所需承受的电场强度,获得了电缆系统的安全裕度。研究表明,文中提出的试验方法能够获得高压直流电缆系统安全裕度,研究结果可为高压直流电缆工程的安全运行提供理论和试验依据。

The safety margin of high voltage direct current(HVDC)cable system is the precondition to ensure the long-term safe operation of cable lines.To obtain the highest service voltage of the HVDC cable system,the conductivity characteristics of insulation of cables and accessories are tested in this paper,and the dependence of conductivity on temperature and electric field intensity and the expression of conductivity are obtained.A safety margin test method is proposed based on±80 kV HVDC cable system,the breakdown voltage of the HVDC cable system at the maximum operating temperature of 90℃is tested by applying voltage step by step.The electric field distribution of cable system breakdown is calculated according to the conductivity of cable insulation and accessory insulation,and the safety margin of the cable system is obtained by comparing the electric field intensity during the breakdown of the cable system with the electric field intensity required for long-term operation.The research shows that the safety margin test method proposed in this paper can obtain the safety margin of HVDC cable system,and the research results provide theoretical and experimental basis for the safe operation of HVDC cable engineering.