接地网接地引下线腐蚀故障的分区诊断方法

为了准确地估计接地引下线的腐蚀状况,基于分层约简模型将接地网分解为若干分区,并提出一种接地引下线电阻分区测试与诊断方法。对于每个分区,首先在该分区之外选择足够多的激励位置并分别进行面向公共节点的测试,根据测试结果确定出该分区内各条本征支路电导的比例系数。然后,将激励源的一端分别与各条非公共节点相连,并分别补充1组面向公共节点的测试,就可以分别诊断出各条非公共节点接地引下线的电阻。证明了公共节点的接地引下线电阻无法通过面向该公共节点的测试诊断得到,并提出了一种换区求解法解决了公共节点的接地引下线诊断问题。在一个60支路的实验接地网上进行的实验验证结果表明:提出的方法是可行的并且具有较高的诊断精度。

Region Separated Approach of Corrosion Diagnosis of Grounding Grid Down Lead Lines

To evaluate the corrosion conditions of down lead lines,a grounding grid is divided into several regions based on the hierarchical simplification model,on the basis of which,a novel approach of diagnosing down lead line resistances in each region,respectively,is established. The down lead line corrosion diagnosis of a large-scale grounding grid is divided into several small-scale region based sub-problems to solve,respectively. In each region,the ratios of the intrinsic branch resistances should be firstly worked out according to the data collected by committing the common node oriented tests under sufficient excitations outside the region,respectively. Secondly,the resistances of the down lead lines connected with the non-common nodes can be determined by shifting one of the two poles of the exciter .to connect with each non-common node and adding a common node oriented test,respectively. It is proved that the down lead line resistance connected with the common node can not be determined by the test orienting the same common node. A common node rearrangement methodology is present to solve above problem and the down lead line resistance connected with the common node can be finally reached. An experimental grounding grid with sixty branches is used as an example. With the proposed approach,the down lead line corrosion diagnosis can be divided into several small-scale region based sub-problems to solve,respectively. The results show that the proposed approach is feasible and with high accuracy.