Method for cooperatively controlling multiport flexible DC power transmission system

Abstract

The invention discloses a method for cooperatively controlling a multiport flexible DC power transmission system. The DC power transmission system comprises a dominant convertor station, a wind power plant convertor station, an auxiliary convertor station and an active power control convertor station. The dominant convertor station is used for controlling the DC voltages of the entire system. The wind power plant convertor station is in charge of collecting the active power of a wind power plant group. The auxiliary convertor station is used for assisting to achieve control over the DC voltages of the system. The active power control convertor station is used for transforming constant active power to an AC side power grid. The auxiliary convertor station and the active power control convertor station are both controlled based on the improved DC voltage -active power coastdown adjusting characteristics. The method for cooperatively controlling the multiport flexible DC power transmission system has the advantages of being used for DC voltage control and active power distribution of all convertor stations of the multiport flexible DC power transmission system under any operation stations, and it is guaranteed that the multiport flexible DC power transmission system is in smooth transition between various operation states.

Description

Technical field [0001] The invention relates to the electrical field, in particular to a coordinated control method for a multi-terminal flexible direct current transmission system based on improved down regulation characteristics. Background technique [0002] Under the situation of energy shortage and increasingly severe environmental pollution, countries around the world have continuously expanded their investment in wind and solar power generation. The development of large-scale offshore wind farms has become a major international trend in wind energy utilization. Since offshore wind farms are far away from the coast, the onshore and land grids they are connected to are often weak. The integration of wind power has a greater impact on the stability and power quality of the connected grids. When offshore wind power is developed on a large scale, it is multi-end flexible DC transmission has become the best choice, so its related research has received extensive attention. The D...

AI Technical Summary

Problems solved by technology

This method uses the control mode switching of the standby station to realize the DC voltage control under fault conditions. The defect is that the system fluctuates greatly during the control mode switching process and cannot achieve a smooth transition of the system operating state; at the same time, this method does not give the system Detailed calculation and selection method of parameters

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