摘要
垂直型直流接地极可以有效解决极址选择困难问题,但也将带来土壤温升过高,接地极散流不均匀等难题。为了对接地极运行时的暂态温升进行有效计算,建立了暂态温度场计算模型,并通过试验进行验证。计算首先基于场路耦合法,在考虑接地极自阻的情况下对接地极电流场进行计算,然后将电流场计算结果作为温度场的计算条件,依据Gurtin变分原理构造时空有限元模型,对接地极进行暂态温升计算。试验选取长9m、直径为30mm的圆钢作为接地极,加载113h的直流电流,分别采用热电偶传感器和霍尔电流传感器采集并记录接地极的温升规律以及散流特性。对比分析表明,计算结果与试验结果具有较高的吻合度,验证了算法的有效性,能为实际工程设计提供参考。
DC vertical ground electrode can overcome the location problem. However, it also causes other practical difficulties, such as non-uniform current divergence and high temperature rise. Simulation method and test method were adopted to calculate transient temperature rise of the ground electrode effectively. Considering ground electrode＇s self-resistance, its current field was calculated based on coupling method of electric field and circuit at first. Then, simulated results of the current field were considered to be the boundary condition to calculate the temperature field of the electrode. Based on the Gurtin variational principle, the formula of space-time finite element method was built to calculate its transient temperature rise. A 9 m long round steel with cross diameter as 30mm was used as the ground electrode in practical tests. And DC current through the ground electrode lasts for 113 hours continuously. Thermocouple and hall current sensors were applied to capture temperature rise and current divergence of the ground electrode. And these results were recorded respectively. Comparative analysis indicates that the simulated calculation results are in good agreement with the experimental results, which confirms the effectiveness of the algorithmic. And it provides reference for practical engineering design.
出处
《中国电机工程学报》
EI
CSCD
北大核心
2013年第10期184-190,2,共7页
Proceedings of the CSEE
基金
国家重点基础研究发展计划项目(973项目)(2009CB724500)~~
关键词
垂直型直流接地极
暂态温升
电流场
温度场
时空有限元
试验
DC vertical ground electrode
transient temperature rise
current field
temperature field
space-time finite element method
test
