一种新型高压电缆附件优化设计方法

New Optimal Design Scheme for High Voltage Cable Accessory

针对电缆附件使用中的扩张形变对附件运行可靠性的影响,提出了一种新型高压电缆附件设计方法。该方法首先通过弹性力学理论,详细推导了电缆附件在扩张过程中的形变和位移方程,然后利用此形变和位移方程将电场优化后呈扩张态的附件结构进行结构松弛至生产结构,从而确保电缆附件安装后的最优电场分布。同时根据据国产35kV冷缩电缆结构参数,分析和对比了传统附件设计方法和新型附件设计方法对附件电场分布的影响,并通过实际电缆附件的结构扩张和松弛过程验证了附件形变和恢复方法的正确性。仿真和计算结果表明:电缆附件撑开时,绝缘内侧到外侧位移量非线性降低,附件厚度减薄、长度变短,应力锥角度、高压屏蔽管端部形状均偏离附件结构设计尺寸,造成附件界面电场、绝缘内部电场增加,而采用提出的新型电缆附件设计方法,能够有效确保电缆附件扩张后的最优电场分布。

Considering the effects of expansion and deformation after accessory installation on the reliability of cable accessory in service, a new optimal design scheme was proposed for high voltage cable accessory. The deformation and displacement equations of cable accessory during expansion were deduced in detail with the theory of elasticity, then the production structure was obtained via the optimized structure relaxation in an expansive state to ensure the optimum electrical field after accessory installation. According to the structure parameters of the domestic 35 kV cold shrinkage cable, the effects on electrical field distribution of cable accessory were analyzed by comparing the proposed and the traditional design schemes, then the deformation and recovery method were verified. The simulation and calculation show that the displacement nonlinearly decreases from inside to outside of the insulation during cable accessory expansion~ the expanded accessory leads to a thinner main insulation thickness and a shorter length; the angle of stress cone and the end shape of high voltage shielding tube deviate from the design structure, which results in enhanced electric field at the interface and the end of HV shielding tube.