基于磁热力耦合的高压大截面电缆热机械效应研究

Thermal Mechanical Effects Research Based on Magnetic Thermal Mechanical Coupling Fields for High-voltage Cables with Large Section

高压大截面电缆热机械效应所产生的热应力与热应变会挤压和破坏电缆绝缘层结构,是影响电缆运行可靠性的重要原因之一。为实现高压大截面电缆热应力与热应变的定量计算,以两端抱箍固定的高压大截面电缆为研究对象,建立电缆磁热力耦合的有限元计算模型。计算电缆电磁损耗,将其作为载荷施加到有限元模型中,计算高压大截面电缆各层热应力与热应变。ANSYS仿真结果表明:高压大截面电缆热应力主要分布在导体与金属护层中,电缆其他各层热应力较小。通过数据拟合,确定导体与金属护层热应力与负荷电流的二次函数关系式,为高压大截面电缆运行状态监测提供理论参考。

The thermal stress and strain produced by the thermal mechanical effect of high-voltage cable with large section can squeeze and destroy the structure of cable insulation layer,which has become one of the important reasons affecting the reliability of cable operation.In order to realize the quantitative calculation of thermal stress and thermal strain of high-voltage cable with large section,the finite element calculation model of cable’s magnetic thermal mechanical coupling field is established,which takes a high-voltage cable with large section fixed with hoops at both ends as a modeling object.The electromagnetic losses of cable are calculated,which are loaded on the finite element model as the excitation to calculate thermal stress and thermal strain on each layer of high-voltage cable with large section.Simulating results show that thermal stress of high-voltage cable with large section is mainly distributed on the conductor and the metal sheath,but thermal stress of the other layers of cable is smaller.The relationship expression between thermal stress of the conductor and the metal sheath and load current is proposed by the method of data fitting,which provides a theoretical reference for operation condition monitoring of high-voltage cable with large section.