Analysis method and device for cascading fault of transmission section of AC/DC power grid

Abstract

The invention discloses an analysis method and device for a cascading fault of a transmission section of an AC / DC power grid. The method comprises the following steps: selecting an AC transmission section of a power grid, and obtaining the line current data of transmission lines in the AC transmission section; adopting a preset electromechanical electromagnetic simulation model to calculate powerflow transfer coefficients among the transmission lines in the AC transmission section according to the line current data of the transmission lines; calculating the maximum overload rate of the transmission lines in the AC transmission section according to the power flow transfer coefficients among the transmission lines in the AC transmission section; obtaining a line fault tripping sequence of the AC transmission section according to the maximum overload rate of the transmission lines in the AC transmission section; and carrying out simulation calculation by adopting the electromechanical electromagnetic simulation model to obtain a cascading fault tripping sequence of the AC transmission section according to the line fault tripping sequence. Mutual influence between alternating currentand direct current in the cascading fault process can be accurately reflected.

Description

technical field [0001] The invention relates to the technical field of simulation analysis of cascading faults in electric power systems, in particular to an analysis method and device for cascading faults of transmission sections of AC and DC power grids. Background technique [0002] As the power grids in various regions are interconnected through DC or AC to form a larger-scale AC-DC hybrid power grid, grid faults are more likely to spread to a wider range through cascading faults, causing greater harm to the safe operation of the grid. There have been many blackouts caused by cascading faults at home and abroad, which shows that cascading faults have become one of the important factors that threaten the safe operation of power grids. [0003] Scholars at home and abroad have carried out research on cascading failures and achieved a lot of results, but the traditional theories, models and analysis methods of cascading failures in AC power grids are difficult to apply to c...

AI Technical Summary

Problems solved by technology

[0003] Scholars at home and abroad have carried out research on cascading failures and achieved a lot of results, but the traditional theories, models and analysis methods of cascading failures in AC power grids are difficult to apply to cascading failures in AC and DC power grids, and some of them are suitable for cascading faults in AC and DC power grids. , models and analysis methods are relatively simple and cannot accurately reflect the characteristics of cascading faults, especially the mutual influence between AC and DC.

[0004] It is generally believed that the DC system fault will affect the power flow transfer of the AC system and the transmission power of the transmission section, and the AC fault will affect the DC commutation bus voltage and cause commutation failure and blockage. However, there are still problems in how to accurately analyze the above characteristics

If the electromechanical transient simulation is used, the simulation of the commutation failure characteristics of the DC system is inaccurate. If the electromagnetic transient simulation is used, it will be limited by the scale and the power grid needs to be simplified first, making the simulation of the AC system characteristics inaccurate.

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