双层绝缘结构高压直流电缆电场分布仿真

发布时间：2018-10-20 14:08

【摘要】：参照油纸绝缘高压交流(HVAC)电缆的分阶绝缘设计思想,采用不同非线性绝缘材料制造具有双层绝缘结构的高压直流(HVDC)电缆来改善电场分布以及减薄绝缘层厚度是一种可能的解决途径。为了从理论上验证双层绝缘设计理念在HVDC电缆绝缘设计中的可行性,采用多物理场耦合软件仿真研究了不同温度梯度、不同施压方式下分层半径对双层绝缘结构HVDC电缆绝缘稳态和暂态电场分布的影响规律,在此基础上定义了同时考虑稳态、暂态电场和温度梯度多重因素的综合绝缘利用系数,并提出了按绝缘材料的电导率内小外大排列、相对介电常数内大外小排列确定内外层绝缘原则和综合绝缘利用系数最高的分层半径确定原则,最后验证了该双层绝缘设计原则的合理性。电场仿真结果发现:与单层绝缘电缆相比较,双层绝缘结构HVDC电缆在高温度梯度下可显著改善电缆绝缘稳态和暂态电场分布,且温度梯度越高改善效果越显著;雷电冲击过程中绝缘内的暂态电场分布受直流稳态过程形成的界面及空间电荷的影响,而双层绝缘结构HVDC电缆绝缘稳态过程中形成的界面及空间电荷与温度密切相关,因而温度也是影响雷电冲击过程中绝缘暂态电场分布的因素。
[Abstract]:Referring to the idea of step insulation design of oil-paper insulated high-voltage AC (HVAC) cable, It is possible to use different nonlinear insulating materials to fabricate HVDC (HVDC) cables with double-layer insulation structure to improve the electric field distribution and to reduce the thickness of insulation layer. In order to verify theoretically the feasibility of double-layer insulation design concept in HVDC cable insulation design, different temperature gradients are simulated by multi-physical field coupling software. The influence of delamination radius on the steady-state and transient electric field distribution of double-layer insulated HVDC cable under different pressure conditions is discussed. Based on this, the comprehensive insulation utilization coefficient is defined, which considers the multiple factors of steady-state, transient electric field and temperature gradient simultaneously. The principle of internal and external insulation is determined according to the internal and external conductivity of insulating materials, the relative dielectric constant is larger than that of internal and external, and the principle of determining the radius of layered insulation with the highest comprehensive insulation utilization coefficient is proposed. Finally, the rationality of the design principle is verified. The electric field simulation results show that compared with single-layer insulated cable, double-layer insulated HVDC cable can significantly improve the steady state and transient electric field distribution of the cable at high temperature gradient, and the higher the temperature gradient, the better the effect. The transient electric field distribution in the insulation during lightning shock is affected by the interface and space charge formed by the DC steady state process, while the interface and space charge formed during the steady-state insulation of the double-layer insulated HVDC cable are closely related to the temperature. Therefore, temperature is also the influence factor of transient electric field distribution during lightning shock.
【作者单位】：哈尔滨理工大学工程电介质及其应用技术教育部重点实验室;
【基金】：国家重点基础研究发展计划(973计划)(2014CB239504)~~
【分类号】：TM247

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