±500 kV直流电缆负荷循环系统温度控制仿真研究

Simulation Study on Temperature Controlling of ±500 kV HVDC Cable Load Cycle System

直流电缆负荷循环系统是开展全尺寸电缆绝缘材料性能研究的重要设备,核心功能是实现绝缘层温度梯度和导体温度的精确控制。为了研究±500 kV直流电缆负荷循环系统中控温介质的流速对绝缘层温度梯度和导体温度的影响,在COMSOL Multiphysics中建立了水循环回路的有限元模型,对直流电缆、循环水及保温水管开展了热流固耦合仿真。通过改变水的流速,研究了绝缘层温度梯度和导体温度的轴向差异变化情况,并对水温和线芯电流进行了修正。结果表明:增大水的流速有利于降低水温的波动,当流速为0.3 m/s以上时,绝缘层温度梯度和导体温度的轴向差异均低于1℃;给出了迭代计算水温和线芯电流的方法,从而将绝缘层温度梯度和导体温度的误差均控制在±1℃以内,满足系统对控温精度的要求。

HVDC cable load cycle system is a key equipment for the research of the insulation properties in full-sizecable,and its chief function is to control both the conductor temperature and the temperature gradient across the in-sulation precisely.Aiming to study the influence of the flow rate of the temperature-control medium on the conductortemperature and the temperature gradient across the insulation in the±500 k V HVDC cable load cycle system,a fi-nite element model of the water cycle channel was established in COMSOL Multiphysics,and the thermo-fluid-solidcoupling simulations of the HVDC cable,circulating water,and thermal insulation pipe were carried out.The axialdifferences of the conductor temperature and temperature gradient across the insulation were studied by controllingthe flow rate of the water,and the water temperature and the current were also corrected.The results showed that thewater’s temperature fluctuation reduced with the increasing of its flow rate,and when the latter was 0.3 m/s,the axi-al differences of both the conductor temperature and temperature gradient were less than 1℃.The iterative calcula-tion method of the water temperature and current magnitude was proposed,which could limit the errors of the conduc-tor temperature and temperature gradient within±1℃to meet the demand of the temperature control in the cableload cycle system.