Short circuit current acquisition method for electric power system including impedance matching balance traction transformer

Abstract

The invention discloses a short circuit current acquisition method for an electric power system including an impedance matching balance traction transformer. The short circuit current acquisition method comprises the following steps: finding a node admittance matrix under the symmetric component of the electric power system before the fault; obtaining a node admittance matrix under the symmetric component of the electric power system after the fault by modifying elements related to fault points in the node admittance matrix according to the short circuit position and the type; obtaining a node injection current column vector under the symmetric component of the electric power system after the fault according to a node injection current column vector under the symmetric component of the electric power system before the fault; obtaining the voltage of each node after the fault according to a system network equation after the fault; and obtaining each branch circuit after the fault according to each node voltage and each branch admittance obtained. The method is based on a symmetric component method and the node admittance matrix, thereby solving the technical problems that the multiple short circuit fault analysis cannot be conducted on an asymmetrical electric power system connected with the impedance matching balance traction transformer by the existing method. The method provided by the invention is conveniently integrated to the existing short circuit current acquisition software.

Description

technical field [0001] The invention belongs to the technical field of short-circuit current analysis of an AC power transmission system, and in particular relates to a short-circuit current acquisition method of a power system including an impedance matching balanced traction transformer. Background technique [0002] Short-circuit fault is a serious fault in power system. In many fields of power system operation and design, it is necessary to obtain the short-circuit current of the power system. At present, there is a relatively mature method for obtaining the short-circuit current of the power system. [0003] my country's power system supplies power to the traction power supply system through traction transformers. Impedance matching balanced traction transformers are widely used in my country. Its structure is asymmetrical in three phases. When connected to the power grid, the power grid will become a three-phase asymmetrical system. , so that the traditional short-circu...

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Problems solved by technology

[0004] In view of the above defects, the present invention provides a method for obtaining short-circuit current of a power system with an impedance-matched balanced traction transformer, aiming at solving the problem that the structure of the power system is asymmetric due to the access of the impedance-matched balanced traction transformer, so that the symmetrical component method cannot be used to calculate the short-circuit current of the power system. Technical Issues in Conducting Short Circuit Analysis

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