A method and system for decoupling section pre-screening applied to AC and DC systems

Abstract

The invention discloses a splitting surface pre-screening method and a splitting surface pre-screening system applied to an alternating-current / direct-current system. The splitting surface pre-screening method includes simulating asymmetrical faults in three-phase voltage of a bus bar i; acquiring three-phase asymmetric indexes of all bus bars; constructing a correlation matrix according to the three-phase asymmetric indexes of all the bus bars; subjecting the correlation matrix to K-core decomposition so as to obtain a K-core value of each bus bar; screening out the bus bar with the maximum degree of influence on the alternating-current / direct-current system according to the K-core value of each bus bar; deleting the bus bar with the maximum degree of influence on the alternating-current / direct-current system from a splitting surface composed of multiple lines, and splitting the alternating-current / direct-current system according to the splitting surface. The splitting surface pre-screening method and the splitting surface pre-screening system applied to the alternating-current / direct-current system have the advantages that on one hand, stability of the alternating-current / direct-current system subjected to splitting control is guaranteed, and on the other hand, the size of a splitting surface search space is decreased, so that operation time is saved and operation efficiency is improved.

Description

technical field [0001] The invention relates to the field of electric power systems, in particular to a method and system for pre-screening split section sections applied to AC and DC systems. Background technique [0002] In recent years, with the gradual increase in the voltage level of the high-voltage direct current transmission (HVDC) transmission line (±800kV has been built, ±1100kV is under construction), the power of its transmission is also gradually increased. As more and more HVDCs are built and put into production, once serious faults such as continuous commutation failure and single- and double-pole locking occur, it will have a great impact on the stable operation of the power system. As the last of the three lines of defense in the power system, decoupling control protects the power system as much as possible and avoids large-scale blackouts by dividing the large power system into several synchronous subsystems, or cutting off the unstable parts of the system....

AI Technical Summary

Problems solved by technology

[0003] The traditional decoupling control method is based on offline control, which cannot cope with various emergencies in the power system

Although the traditional adaptive decoupling control uses online control methods to solve this problem, the traditional adaptive decoupling control only considers the coherence constraints of the unit, the power balance constraints of the subsystems, and the static stability constraints of the system after decoupling. On the one hand, the control method does not consider the influence of decoupling control on the DC line. On the other hand, the feasible solution space in the search process increases exponentially with the increase of the system scale. When it is applied to the online decoupling of large systems, it will face the curse of dimensionality. The problem is that the calculation efficiency is low, and it is impossible to provide an effective decoupling solution in a short time after a large grid instability fault occurs.

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