Substation grounding grid corrosion fault online diagnosis method applying multiple excitation sources

Abstract

The invention discloses a substation grounding grid corrosion fault online diagnosis method applying multiple excitation sources, which comprises the steps of (1) determining the position of measuringports, calculating data such as the voltage of each port and the branch current before corrosion, and measuring the voltage of the corresponding ports of a grounding grid after corrosion under the condition of multiple excitation sources; (2) constructing a fault diagnosis equation according to the Tellegen's theorem, and calculating values of corresponding matrixes of the diagnosis equation by using the data in the step (1); (3) solving the fault diagnosis equation based on a piecewise linearization principle, building a linear programming model on each linearization interval, calculating anoptimal solution with the energy loss being the minimum by using a simplex method, and updating the calculation data; and (4) continuously performing iterative computation until a convergence condition is met, and returning a resistance value of each branch after corrosion. The method disclosed by the invention can accurately diagnose the position of a fault branch; and the calculation result canapproach to a true value of the branch resistance after corrosion, and an approximate reference corrosion multiple is provided for the branch resistance after corrosion.

Description

technical field [0001] The invention belongs to the field of electrical engineering, in particular to a method for diagnosing corrosion faults of substation grounding grids. Background technique [0002] The grounding grid provides a common reference ground for various electrical equipment in the power generation and substation, and plays the role of discharge and voltage equalization, which can effectively ensure the safety of staff and electrical equipment. The domestic grounding grid is mainly made of ordinary steel or hot-dip galvanized flat steel, which has poor corrosion resistance and is prone to corrosion failures due to factors such as soil action. The occurrence of corrosion faults will reduce the reliability of the grounding grid, and even damage equipment and cause safety accidents. Therefore, regular diagnosis and evaluation of the corrosion status of the grounding grid is of great significance to ensure the safe operation of power generation and substations. ...

AI Technical Summary

Problems solved by technology

The main shortcomings of the existing grounding grid corrosion fault diagnosis methods are: 1. The non-linearity of the diagnostic equation cannot be effectively dealt with so that the diagnostic equation is only applicable to the case of slight corrosion of the branch conductor; 2. It cannot effectively ensure that the iterative calculation is Directional Approximation of True Value of Branch Resistance

The problem of solving underdetermined equations has been discussed in the theory of fault diagnosis and has not been finally solved. A more feasible method is to use linear programming and the principle of minimum energy to solve the problem, but because of the diagnostic equations The number of independent equations is small, and the measurable grounding downconductor is not fully utilized, which will have a certain impact on the accuracy of the calculation results

For the nonlinear problem of underdetermined equations, only the iterative method cannot effectively ensure that the iterative calculation approaches the true value of the branch resistance

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