±535 kV直流电缆绝缘厚度理论设计与验证

Theoretical design and verification of ±535 kV DC cable insulation thickness

为确定张北柔性直流工程直流电缆的绝缘厚度,文中提出了一种直流电缆绝缘厚度设计方法;分析了寿命指数、击穿场强换算系数和Bahder系数3个关键因素对绝缘厚度的影响;通过建立方程组计算了±535kV直流电缆绝缘厚度;采用有限元仿真方法计算了不同电导率温度系数、电导率电场系数和绝缘温差下的电场分布和电场畸变率。研究表明,不同电导率温度系数、电导率电场系数和绝缘温差下,±535kV直流电缆绝缘电场畸变率均符合国家标准的要求,设计方法的合理性得到验证。研究结果为直流电缆绝缘厚度设计和验证提供了理论指导,为张北工程的建设提供技术支撑。

In order to determine insulation thickness of DC cable in Zhangbei HVDC flexible project,a design method of insulation thickness of the DC cable is presented.The influences of life index,breakdown field intensity conversion coefficient and Bahder coefficient on insulation thickness are analyzed.The insulation thickness of ±535 kV DC cable is calculated by establishing equations.The electric field distribution and electric field distortion rate under different conductivity temperature coefficient electric conductivity electric field coefficient and insulation temperature difference are calculated by finite element simulation.The results show that the insulation electric field distortion rate of ±535 kV DC cable meets the requirements of national standards under different conductivity temperature coefficient,conductivity electric field coefficient and insulation temperature difference,and the rationality of the design method is verified.The research results provide theoretical guidance for the insulation thickness design and validation of DC cable and provide technical support for the construction of Zhangbei project.