接地网腐蚀故障诊断可测性分析

Testability Analysis of Corrosion Diagnosis for Grounding Grids

接地网支路电阻的可测性是由网络的拓扑结构和可及节点分布决定的,与支路的电阻值无关。由此提出了一种适用于接地网腐蚀诊断的可测性分析方法,利用网络变换先消去不可及节点,然后反向推导,逐步确定各条支路的可测性。在此基础上提出了诊断可信度指标,指示各条支路诊断结果的可信程度,并构造了可信度计算公式。诊断结果验证了这个方法的有效性,并且可信度指标能够较好地反映诊断结果的误差情况。可测性分析和可信度指标可以给工程人员的实际诊断工作提供有价值的信息。

Testability of grounding grids is decided by network topology and reachable nodes’ location rather than resistance. In order to research the testability, a new method which applied to corrosion diagnosis is presented. In this method, unreachable nodes are eliminated by network transformation, and then the testability is confirmed gradually in reverse direction. Creditability index is firstly proposed to indicate the credibility of diagnosis result, and the calculating formula is also established. Simulation results show the validity of this approach, and the creditability index can well reflect the errors of diagnosis results. Testability results and creditability index provide valuable information for the actual diagnosis work.