Multi-terminal DC (Direct Current) power transmission system for combined synchronization of wind power plant and conventional power plant

Abstract

The invention discloses a multi-terminal DC (Direct Current) power transmission system for combined synchronization of a wind power plant and a conventional power plant. The multi-terminal DC power transmission system comprises two rectification stations and an inversion station, wherein the wind power plant is connected to an AC (Alternating Current) bus side of one rectification station, the conventional power plant is connected to an AC bus side of the other rectification station, the inversion station is connected to a load center, DC buses of the two rectification stations, corresponding to the inversion station, are connected together by a DC power transmission line, thus the multi-terminal DC power transmission system is formed. According to the multi-terminal DC power transmission system disclosed by the invention, a matched conventional power plant does not need to be built near the wind power plant, and the multi-terminal DC power transmission system has no any requirements on a geographic position of the conventional power plant combined with the wind power plant; compared with a manner of AC power grid synchronization, the multi-terminal DC power transmission system does not need a local AC power grid near the wind power plant to level the power fluctuation of wind power; and compared with a scheme of synchronization of wind power plant through voltage source type DC power transmission, the multi-terminal DC power transmission system can enable the electricity transmission power of a single-circuit bipolar line to be 6,400MW or more by adopting the traditional mature ultra-high-voltage current conversion technology.

Description

technical field [0001] The invention belongs to the technical field of power system transmission and distribution, and in particular relates to the application technology of wind power generation connected to a grid through large-scale long-distance DC transmission. Background technique [0002] According to the national wind power development plan, seven 10 million-kilowatt wind power bases in Hami, Jiuquan, Hebei, Jilin, Jiangsu Coastal, Mengdong, and Mengxi will be completed in 2020. It is planned to build 58.08 million kilowatts by 2015 and 90.17 million kilowatts in 2020. , accounting for about 78% of the country's total installed wind power capacity. [0003] Due to the huge installed capacity of wind power, each base has been dubbed the title of "Three Gorges on Land". However, what does not match the total installed capacity is that most of the wind power bases are located in Northwest China, the local AC power grid has a low power load, and its own absorption capac...

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Problems solved by technology

The scheme of Chen Xia and others still needs the local AC grid to stabilize the wind power fluctuations, which is essentially the same as wind power generation passing through the local AC grid. Wind farms connected to the AC grid will bring stability problems to the local grid, and disturbances to the local grid, etc. It will also affect the stable operation of the wind farm

When the scheme in US2010091527 is used to transmit wind power, the withstand voltage level of the voltage source converter is required to match the voltage level of the traditional two-terminal DC transmission line. At present, there is no voltage source converter technology that can reach this voltage level.

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