A decentralized autonomous voltage balance control method among multiple converter units in a converter station of a flexible direct current transmission system

Abstract

The invention discloses a method for decentralized autonomous type voltage balance control of multiple converter units of a converter station of a flexible direct-current transmission system. The method comprises the steps of firstly obtaining the average direct-current voltage of each converter unit according to the total direct-current voltage of the converter station of the flexible direct-current transmission system and the number of converter units in the converter station; obtaining the average active power of each converter unit according to the total active power transmitted by the converter station and the number of the converter units; obtaining the direct current voltage ratio of the corresponding converter unit according to the real measurement and the average direct current voltage of the direct current voltage of each converter unit; then multiplying the obtained direct current voltage ratio by the obtained average active power to obtain a power command value of the corresponding converter unit. The obtained power command value is scattered and introduced into each converter unit, and autonomous regulation of the voltage of the converter unit is achieved. By adoptingthe method, the problem of power unbalance caused by uneven distribution of direct-current voltages of the multiple converter units in the flexible direct-current constant-active power converter station can be solved.

Description

technical field [0001] The invention relates to the technical field of power transmission and distribution, in particular to a decentralized autonomous voltage balance control method among multiple converter units in a converter station of a flexible direct current transmission system. Background technique [0002] Modular multilevel converter (MMC) has attracted extensive attention due to its advantages of modularity, low harmonic content, low loss, and the ability to supply power to passive networks. There are broad application scenarios for wind farm grid connection, grid interconnection, and high-voltage and large-capacity power changes. The main problem in the application of MMC-HVDC in long-distance large-capacity power transmission is that it is limited by the manufacturing level of existing power devices, and its DC voltage and DC current are relatively small. Drawing lessons from the structure of a single 12-pulse converter in series in the UHV scenario of the trad...

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Problems solved by technology

[0004] The purpose of the present invention is to provide a method for decentralized autonomous voltage balance control among multiple converter units in a converter station of a flexible direct current transmission system. Self-regulation of its own voltage, so as to solve the power imbalance problem caused by the uneven distribution of DC voltage caused by multiple converter units in the flexible DC constant active power converter station

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