Research On Corrosion Fault Diagnosis Algorithm Of Grounding Grid For Traction Substation

The grounding grid of traction substation is one of the important facilities which ensuresafe and reliable operation of the traction power supply system. However, grounding grid inthe composition of metal conductor in the process of underground running will inevitablysuffer corrosion even when serious breakage, leading to its security performance is greatlyreduced. Research on the method of corrosion fault diagnosis for grounding grid is helpful tograsp the operation of the grounding grid, find hidden danger timely and take appropriateaction to safeguard personnel life and property safety. The algorithm adopted in solving faultdiagnostic equation is the core step of the corrosion fault diagnosis for grounding grid.Therefore, the corrosion fault diagnosis algorithm of branch conductors of grounding grid fortraction substation is studied in this thesis.By analyzing the operation characteristics and the reasons of the corrosion fault forgrounding grid of traction substation, the corrosion fault diagnostic equations of groundinggrid for traction substation are built based on the corrosion fault diagnostic equations of thegrounding grid for substation, which according to the basic principle of parameteridentification method, the method of node analysis and the sensitivity matrix. Then theobjective function is constructed by applying the lowest energy theory. Moreover, ParticleSwarm Optimization (PSO) algorithm and Chaos Particle Swarm Optimization (CPSO)algorithm are respectively used to solve the equations.The algorithm is verified by simulation of a220kV and24branches grounding grid oftraction substation. Firstly, equivalent circuit of analog grounding grid is built in Matlab.Then fault diagnostic equations are formed by getting measured data through simulation.Secondly, then the equations are respectively solved by PSO algorithm and CPSO algorithmby programming. Finally, the degree of corrosion and breakage for branch conductors can bejudged by the ratio of diagnostic value to normal value of branch conductors.The simulation shows that location and fault degree of corrosion even broken branchesfor grounding grid can be diagnosed and the underdetermined diagnostic equations areeffectively solved by PSO algorithm and CPSO algorithm. CPSO algorithm has better globalsearch ability because of combining with chaos optimization and the characteristics of PSO.The deviation of diagnosis based on CPSO algorithm is less than PSO algorithm, so corrosiondiagnosis accuracy of grounding grid is increased.Based on the method of corrosion fault diagnosis on the basic of CPSO algorithm forgrounding grid is feasible after being verified, the program of intelligent corrosion faultdiagnosis system for grounding grid of traction substation is proposed, which include theoverall system and hardware structure. And the workflows of functional sub-models are also designed through the analysis of functional requirements for the system. The project is helpfulto practical research on intelligent corrosion fault diagnosis of grounding grid for tractionsubstation.