A DC Bias Calculation Method Based on Field-circuit Coupling in 3D Asymmetric Structured Soil Model

Abstract

A DC bias calculation method based on field-circuit coupling under a three-dimensional asymmetric soil model. The size of the soil model is determined by the DC bias influence range that needs to be considered, and the model is discretized into small cubes with a side length of 2m; through the actual Measure point data to determine the block division of the model; map the inverted 3D resistivity to each block, and map the non-3D resistivity data after conversion; determine the coordinates of the injection point through the injection test data, apply excitation, and determine the boundary conditions , divide the grid, and calculate the surface potential; determine the observation path, compare it with the results of the injection test, and correct the soil model; obtain the wiring diagram of the power system around the ground electrode, coordinates and other parameters, and build a DC circuit model; input the potential of each node, and carry out DC bias calculation. Starting from the initial model, the invention improves the calculation accuracy of the DC bias magnetic field, reduces the possibility of protection malfunction or refusal to operate after the DC project is put into operation, and improves the stability of the power system operation.

Description

technical field [0001] The invention belongs to the fields of soil electrical structure modeling and transformer bias current calculation, and in particular relates to a DC bias calculation method based on field-circuit coupling under a three-dimensional asymmetric structure soil model, which is mainly used for DC bias calculation. Background technique [0002] High-voltage direct current transmission has the characteristics of large transmission capacity and high economy, and has developed rapidly under the background of unbalanced distribution of energy and load centers in my country. With the increase of transmission capacity and voltage level, the influence of DC grounding pole on the DC bias magnetic field of the surrounding power system becomes more and more prominent. Therefore, in the site selection and design stage of the DC grounding pole, it is necessary to evaluate the magnetic bias influence of the surrounding power system. The accuracy of the assessment is dir...

AI Technical Summary

Problems solved by technology

Although this method corrects the soil model, the horizontal layered soil model adopted greatly simplifies the real electrical structure, and only considers the change of soil resistivity in the depth direction, which is different from the actual situation. The difference is large, so there is still a large error in the calculation result of the bias current

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