A new approach of testability evaluation for grounding grid corrosion diagnosis

In order to evaluate the testability under the given touchable nodes, a grounding grid is hierarchically simplified into six levels, such as Normal Grounding Grid, Quasi-Circuit-Block, Circuit-Block, Block-Grid, Touchable Grounding Grid and Intrinsic Grounding Grid. The branches of a grounding grid can be classified into two kinds such as clear-branches and uncertain-branches. Rules to classify the clear branches and uncertain branches are established. A numerical method to evaluate testability of Circuit Blocks is presented. An iteration approach of testability evaluation is suggested. A grounding grid with sixty branches is given as an example showing the correctness and feasibility of the proposed approaches.