Power grid fault calculation method comprising back-to-back direct current power transmission

Abstract

The present invention discloses a power grid fault calculation method comprising back-to-back (BTB) direct current power transmission. The method comprises the following steps: inputting system parameters and control parameters of a BTB power transmission system; determining a fault side alternating current system constraint equation formed by a fault side network topology structure and a fault boundary condition, determining a non-fault side alternating current system constraint equation formed by a non-fault side network topology structure, and determining a direct current constraint equation between the direct voltage and the direct current at the direct current side formed by direct current control characteristics of two sides; establishing current converter current switch function models of direct current systems of two ends (img file='DDA0001280678930000011.TIF'wi='43'he='67' / ) and a voltage switch function model (img file='DDA0001280678930000012.TIF'wi='56'he='66' / ); combining the fault side alternating current constraint equation, the direct current constraint equation and the current convertor switch function solution fault side power frequency bus voltage (img file='DDA0001280678930000013.TIF'wi='75'he='63' / ); and performing iterative computations, quitting the computations when the variable errors satisfy the computation requirement or the number of iterations exceed the maximum range, and outputting alternating current power grid current conversion bus power frequency voltage computation result of two ends of the BTB system. The power grid fault calculation method comprising back-to-back direct current power transmission is fast in computation speed, high in accuracy and high in applicability, and has high practical engineering values at the aspects of alternating current power grid fault computation comprising the back-to-back direct current transmission and the relay protection setting cooperation thereof.

Description

technical field [0001] The invention relates to the research field of power system fault calculation methods, in particular to a power grid fault calculation method including back-to-back direct current transmission. Background technique [0002] With the commencement of construction of the Luxi back-to-back DC project, which ranks first in the world in terms of voltage level and construction scale compared with similar projects, it marks that the application of back-to-back projects in my country has entered a new stage. As an important way of asynchronous networking between large power grids, back-to-back DC can effectively reduce the mutual influence between the grids connected on both sides; The electrical connection is close, so there is a certain fault interaction between the AC systems on both sides. That is, when one side of the AC power grid fails, the opposite side power grid will be affected to a certain extent through the AC-DC-AC interaction with the back-to-ba...

AI Technical Summary

Problems solved by technology

However, the above studies are all based on the premise that the conventional DC transmission line is long, and when the AC power grid on one side fails, only the converter station on this side is affected, while the converter station on the other side is basically not affected.

Due to the close electrical connection between back-to-back DC rectifiers and inverters, the above analysis method that only considers the converter station on the fault side is not suitable for back-to-back DC transmission systems

At present, the research on back-to-back DC mainly focuses on engineering scheme research, analysis and optimization of control system, performance analysis of AC side protection, and analysis of reasons for back-to-back DC commutation failure. analyze

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