Simulation modeling method for subway stray current distribution in urban power grid

Abstract

The invention discloses a simulation modeling method for subway stray current distribution in an urban power grid. The method comprises the following steps: establishing an alternating-current power grid ground equivalent model according to a power supply mode and a topological structure of a power system, and solving ground equivalent resistance among grounding substations according to distancesamong the grounding substations, the magnitude of grounding resistance of a grounding grid and ground resistivity, thereby establishing an urban power grid ground equivalent network; connecting an external control current source element to a neutral line of a grounding transformer of a certain grounding transformer substation, and controlling the current source by adopting the actual measurement data of the neutral point direct current of the grounding transformer substation in the early departure period; and finally, simulating and adjusting the size correction model of the initial groundingresistance R of the equivalent power supply until a final simulation model is obtained. According to the method, the distribution rule analysis of the subway stray current in the urban power grid andthe influence factor research of the stray current distribution can be realized, and guidance suggestions are provided for the treatment of the transformer direct-current magnetic bias caused by the stray current.

Description

technical field [0001] The invention relates to the field of power system modeling, in particular to a simulation modeling method for subway stray current distribution in urban power grids. Background technique [0002] With the network of urban rail transit scale, the dynamic change of power supply current and the gradual aging of rail-to-ground insulation, the stray current of subway also shows the trend of network, persistence and superimposed increase. Because the subway uses DC power supply in actual operation, and due to the iron filings, dust and leakage impedance reduction caused by rail friction, the rail and the earth cannot be completely insulated, so part of the power supply current will leak from the rail to the earth. form subway stray currents. The current protection measures against the stray current in the subway still cannot completely collect and control the stray current in the earth, resulting in a part of the stray current not being able to flow back t...

AI Technical Summary

Problems solved by technology

[0004] At present, the distribution law of subway stray current in the urban power grid is not yet clear, and the influence of the electrical parameters of the components of the AC system and the switching of capacitor DC blocking devices on the distribution of stray current in the AC power grid is not yet clear. Therefore, the study of subway stray current The simulation modeling method of the current distribution in the AC system is of great significance to the research and treatment of the DC bias of the transformer caused by the stray current of the subway

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