Study On Corrosion Diagnosis Method And Evaluation Of Corrosion Effect On The Grounding Grids

Corrosion is one of the most important cause of the grounding performance deterioration. The grounding grid corrosion diagnosis including corrosion breakpoint diagnosis and corrosion degree of the grounding conductor segment diagnosis in two aspects. At present, there were no effective diagnostic methods in two aspects.Acording to the grounding grid corrosion diagnosis breakpoint in the presence of "lead on" problem, a magnetic source diagnosis method of grounding grid corrosion breakpoints is proposed. The method of excitation induced current in grounding conductor surface by two horizontal magnetic dipole, the surface detection of induced current magnetic field for two times to determine whether there is a breakpoint conductor. This method has no restriction and diagnosis of grounding contact, by the advantage of less.According to the connection of diagnosis method of grounding grid corrosion problem, the thesis proposes an improved weak polarization of grounding grid corrosion monitoring scheme based on. According to the same material with the same corrosion condition in the same soil regional laws, to test the corrosion condition of electrode corrosion status reflect the conductor segment by monitoring. In the three electrode system has the advantages of simple structure, easy to install. Experiments show that, this scheme can effectively diagnose each conductor section of the corrosion degree.The grounding grid corrosion and the corrosion degree of breakpoint conductor segment information, evaluate the corrosion state of grounding grid, the grounding grid corrosion severity clearly affect the performance, provide the basis for making the optimal maintenance plan and strategy. At present, no grounding grid corrosion assessment research.The grounding grid corrosion mechanism is not clear, the thesis establishes an improved Freschi model, and based on the performance of grounding grid corrosion mechanism is analyzed.In the clear grounding corrosion mechanism, the proposed grounding grid corrosion condition assessment process. According to the degree of corrosion corrosion and the breakpoint conductor section to determine the improvement of R matrix in Freschi model and G matrix, using the improved Freschi model can calculate the characteristic parameters of grounding grid corrosion in the current state, the characteristic parameters of the comparison of the current value and design value indicators, and quantitative assessment of the severity of the grounding grid corrosion performance.The grounding grid corrosion condition assessment, calculation parameters and the corrosion information needs. For there is no effective method and the corrosion degree of the problem, the proposed grounding conductor section corrosion state information database and the degree of corrosion corrosion conductor segment method based on. The corrosion degree of conductor segment, bulk flow capacity through the retrieval of information obtained in a certain period of base conductor corrosion level, and in response to the improved R matrix Freschi model, so as to achieve the degree of corrosion and.According to the corrosion condition evaluation, substation grounding grid, this thesis based on the analytic hierarchy process, to establish the corrosion state considering multiple parameters evaluation model.