基于场路耦合的直流接地极暂态温度场分析

Analysis of transient temperature field in DC grounding electrode based on field-circuit coupling

采用三维有限元法,在考虑地表和空气之间的对流换热情况下,对垂直型直流接地极的暂态温度场进行了计算,得出了垂直型直流接地极暂态温度场的分布规律以及温升曲线.垂直型直流接地极暂态温升值和温升速率与深度正相关,接地极底端温升最高,温升速率最大;垂直型直流接地极的温升速率在初始阶段最大,随着运行时间的增加逐渐减小,直至达到稳态;填充焦炭能有效减小垂直型直流接地极暂态温升值和温升速率.与此同时,还通过大型模拟试验对垂直型直流接地极的温升进行了测量,排除外界因素的干扰,试验值与仿真计算值有较高的吻合程度,这表明了所提出的的仿真计算以及模拟试验都具有较高的准确性.

In this paper,3-D finite element method is applied to calculate the transient temperature field of the vertical DC grounding electrode considering the heat exchange between air and surface;and a distribution law and temperature rise curve are obtained.The positive correlation is observed between the value or increasing speed of temperature rise and depth;the bottom of the grounding electrode gets the highest value and rapid.For the vertical DC grounding electrode,when the grounding-electrode gets heated at first,the temperature rises rapidly;the speed gets lower as time goes and finally it reaches a static temperature rise.Meanwhile,filling in with coke has a great beneficial effect on decreasing the speed and value of the transient temperature rise.At the same time,a simulated experiment on measuring the value of the temperature rise of the vertical DC grounding electrode is carried out.The experiment value and the simulation calculation value are nearly the same,when external factors are neglected,which shows that the simulation calculation and experiment in this dissertation is of high accuracy.