Research On The Substation Ground Network Corrosion State And Fault Diagnosis Methods

The main responsibility of the substation grounding grid is to ensure the safe operation of the power system and the safety of personnel and electrical equipment. It integrates safety grounding, lightning protection and grounding. Because of the economic and social situation, flat steel is used as grounding body in China, instead of the copper conductor which is widely apllied abroad. As a result of deeply buried underground,corrosion and even fracture occurs, which will change the grounding parameters of the grounding grid, and then change the surface voltage distribution. According to the relevant statistics, substation grounding grid breakdown frequently, the equipment and personal safety is in a huge risk.When grounding fault occurs, choosing traditional excavation method for the detection of the pertinence is not strong, low efficiency, slow speed and poor economic benefit. In this paper, according to the measured voltage value of the measurable node,diagnosis of grounding grid fault and diagnosis algorithm of the branch fault, the staff can correctly find the fault, which can save a lot of human, material and financial resources.Diagnosis model and diagnosis algorithm is the core content of grounding grid fault diagnosis. Based on grounding grid resistance model, this paper has a research of grounding grids measurability and grounding grid diagnostic test scheme.Through the research on grounding grid, a reasonable grounding grid diagnostic testing program can be worked out. Select the optimal parameter based on the length of time and the size of the fault, then test grounding grid by the scheme above. Choose the optimal scheme according to the contrastive analysis.In practice, the test scheme is reasonable and the diagnosis results are relatively accurate. The test results of the scheme are consistent with the actual fault values, which can be obtained from the branches of the measured grounding grids. This paper illustrates that the design of the grounding grid diagnostic test program can be applied to the actual grounding grid in the diagnosis of failure.