Method for processing sparsity of AC (alternating current)/DC (direct current) hybrid grid tide current meter

Abstract

The invention discloses a steady equivalent model of a voltage source converter and a common control mode and provides a tide current computing model of a multi-terminal flexible direct current and alternating current hybrid grid. In order to solve the problem of non-structural symmetry and zero diagonal element of a tide current Jacobian matrix caused by a voltage source converter model, a small number of zero elements are processed into non-zero elements to restore the structural symmetry of the Jacobian matrix, a controlled quantity serves as a constant and is substituted into an equation, variables are preferentially ordered to solve the problem of zero diagonal element, and the difficult problem in tide current calculation of a VSC (Vacuum System Controller)-containing direct current and alternating current hybrid grid is overcome with an extremely low sparsity cost. The correctness of the mentioned model and the effectiveness of sparse matrix treatment are verified through simulation run.

Description

technical field [0001] The invention relates to the field of power systems, in particular to the field of grid power flow calculation, in particular to a sparsity processing method for a current meter of an AC-DC hybrid grid. Background technique [0002] Flexible direct current transmission technology (VSC-HVDC) adopts voltage source converter (VSC), which has bidirectional controllability, commutation does not depend on grid zero crossing, low harmonic level, independent adjustment of reactive power and active power, and can supply power to passive network Its flexible control mode and ideal operating characteristics have great technical advantages in solving problems such as large-scale renewable energy grid integration, large-capacity long-distance power transmission, and shortage of transmission corridors. [0003] With the continuous maturity of the fully-controlled device production technology, its production cost has been significantly reduced, and the device capacit...

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Problems solved by technology

[0005] Although there are many researches on flexible DC transmission technology at home and abroad, they mainly focus on the improvement of converter performance, the optimization of model algorithms, and the control improvement under the condition of new energy grid connection. There are few studies on transmission system control, transmission power distribution, and safe and economical operation. Literature 13 "Active power flow optimization method for AC-DC parallel system with flexible DC transmission [J]" (Deng Jianjun, Wen An, Wei Chengzhi, Xun Bin Bin, Tian Lin, Deng Xu. Power System Protection and Control 2014; (11): 118-123) using fuzzy theory to build a multi-objective model of AC and DC systems, but the model for DC system losses is too simple to fully Relationship Between Reaction Loss and DC State Quantity

Document 14 "Sichuan multi-circuit ±800kV DC transmission system DC active power coordination control [J]" (Huang Zhen, Zheng Chao, Pang Xiaoyan, Li Min, Wu Guangning. Power Grid Technology 2011; (05): 52-58) According to Sichuan A coordinated control method is proposed based on the actual characteristics of the AC-DC grid, but this method is based on the traditional DC line. After the application of the flexible DC system, the characteristics of the DC system have changed greatly, and this method also needs to be modified.

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