Field-circuit coupling-based direct current magnetic bias calculation method for soil model adopting three-dimensional asymmetric structure

Abstract

The invention discloses a field-circuit coupling-based direct current magnetic bias calculation method for a soil model adopting a three-dimensional asymmetric structure. The method comprises the steps of determining the size of the soil model through a direct current magnetic bias influence range needed to be considered, and discretizing the model into small cubes with side lengths of 2m; throughactual measurement point data, determining block division of the model; mapping inverted three-dimensional resistivity to blocks, and mapping non three-dimensional resistivity data after conversion;determining stream injection point coordinates through stream injection test data, applying stimulation, determining a boundary condition, dividing grids, and performing surface potential calculation;determining an observation path, performing comparison with a stream injection test result, and correcting the soil model; obtaining a peripheral power system wiring diagram of an earth electrode andparameters such as coordinates and the like, and building a direct current circuit model; and inputting node potentials to perform direct current magnetic bias calculation. Starting from an initial model, the direct current magnetic bias calculation precision is improved; the possibility of protection mal-operation or refusal operation is reduced after operation of a direct current project; and the stability of power system operation is improved.

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...

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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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