Transformer bias magnet current calculation method based on subway near-area earth and power grid model

Abstract

The invention relates to a transformer bias magnet current calculation method based on a subway near-area earth and power grid model, which comprises the following steps: calculating the magnitude of stray current through a resistance network model, then analyzing the change of surrounding ground potential caused by the stray current based on an earth resistivity model, and finally establishing an urban power grid 220kV transformer network topology model to obtain the relationship that the transformer neutral point current changes along with time. The invention provides a calculation method for quantitatively calculating the magnetic bias current of the 220kV transformer in a power grid near a subway line for researching the correlation between the stray current of the subway and the bias magnetic current of the 220kV transformer of the urban power grid, and the method is beneficial to analyzing the influence of the stray current of the subway on the transformer. The defects of a model and a method for calculating the magnetic bias current of the 220kV transformer of the urban network near the subway line in the prior art are overcome.

Description

technical field [0001] The invention relates to the field of urban power grids and transformers, in particular to a method for calculating the bias current of a 220kV transformer based on the ground and power grid models in the vicinity of subways. Background technique [0002] With the continuous development of urban construction, the scale of urban rail transit has become larger and larger, and it has become the most convenient solution for citizens to travel. However, since most urban subways or light rails use DC traction power supply, the rails are not completely insulated from the ground. During the operation of the subway train, there will be DC current leaking from the subway rails into the ground, which constitutes the so-called subway DC stray current. The DC stray current will flow into the transformer winding through the grounding grid of the urban power grid substation, causing the DC bias magnetic saturation of the transformer, causing the vibration and noise o...

AI Technical Summary

Problems solved by technology

Based on this purpose, there is no lack of research in the prior art to establish a static distribution model of stray current for unilateral power supply and bilateral power supply for calculation or analysis, but it is mainly for proving the impact of subway stray current on underground metal pipelines or other metal facilities. However, there are no research literature reports on the establishment of the ground and power grid model in the vicinity of the subway and the calculation of the bias current of the 220kV transformer in the urban network

The urban network transformer is the grid area most affected by the bias current, and the calculation complexity is higher, which has become a defect that cannot be solved by the existing technology

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