Research On Fault Location And Diagnosis Method Of Grounding Grids Based On Electric Network Theory

With the growth of the national economy and the continuous increase in power demand,the safe and stable operation of the power system has received more and more attention.The grounding grid of the substation is a key facility to ensure the safety of electrical equipment and workers in the power system.The conductors of the grounding grid are generally corroded to different degrees after several years of service,and the lack of branch conductors is often caused by human factors during installation work.These have led to frequent accidents caused by grounding grid failures in recent years.In practice project,the usual method of detecting the faults is to excavate randomly during the power cut.The workload is enormous and inefficient.Based on the theory of fault diagnosis and electric network,this paper establishes the mathematical model for corrosion diagnosis of grounding grids.The model was solved iteratively by least-squares method and the port resistance of grounding down lead.However,the traditional electrical network method is relatively random when selecting points,which leads to a huge workload of on-site diagnosis and poor diagnosis effect.Based on this,this paper uses the ATP-Draw simulation platform to simulate the fault situation,combined with the simulation test results based on the port parameter variation,and adopts the method of partition detection,which greatly reduces the measurement of port data with low contribution to fault diagnosis,thereby effectively improving Diagnostic efficiency.Combining the strategy of multiple follow-up visits and successive approximation,multiple follow-up visits and port supplementary tests on the grounding grid can effectively eliminate false fault branches and realize the location of the grounding grid fault.To verify the feasibility of the improved diagnosis method,a grounding grid simulation circuit model is built using ATP-Draw software,and a variety of fault conditions are simulated and calculated.At the same time,the diagnosis effect of direct selection diagnosis and the method are compared,and the method in this paper has improved accuracy and diagnostic efficiency.In order to verify the feasibility of the improved diagnosis method,a grounding grid simulation circuit model is built using ATP-Draw software,and a variety of fault conditions are simulated and calculated.At the same time,the diagnosis effect of direct selection diagnosis and the method are compared,and the method in this paper has improved accuracy and diagnostic efficiency.In order to verify the practicability of the method,I build an irregular grounding grid of 1.6m×1.6m,conduct the experiment in a sand pit.and successfully located the default location of the missing branch.On-site inspection and diagnosis of part of the switchyard area of a 500 k V substation in Xuzhou has been carried out to verify the engineering application value of the method in this paper.