Fault ride-through method for offshore wind power flexible direct current sending-out system

Abstract

The invention discloses a fault ride-through method for an offshore wind power flexible direct current sending-out system, and belongs to the technical field of new energy power generation grid connection. According to the method, the difference between a flexible direct-current power transmission system and a traditional power transmission system is considered, and a flexible direct-current power transmission system control strategy suitable for offshore wind power transmission is designed; the working principle of the direct-current energy consumption device is analyzed, and reasons for large design power and long switching time of the direct-current energy consumption device in engineering are pointed out; aiming at the defects of the direct-current energy consumption device in engineering, a fault ride-through control strategy of voltage reduction of the direct-current energy consumption device and a wind field side converter and active load reduction of a wind power plant is provided, and is compared with a method for fault ride-through only by inputting the direct-current energy consumption device. According to the invention, the problems of large rated power and long switching time of a direct-current energy consumption device used in engineering are solved.

Description

technical field [0001] The invention belongs to the technical field of grid-connected new energy power generation, and in particular relates to a fault ride-through method for an offshore wind power flexible direct current transmission system. Background technique [0002] my country's offshore wind power has developed rapidly in recent years and has gradually moved into the deep sea. At the end of 2019, the cumulative grid-connected installed capacity reached 5.93 million kW, of which Jiangsu's grid-connected capacity reached 4.23 million kW, ranking first in the country. Flexible DC transmission technology is considered to be the first choice for large-scale offshore wind power grid integration in deep and open seas due to its advantages of independent adjustment of active power and reactive power and no need for reactive power compensation. When the onshore power grid fails, the active power output by the grid-connected inverter will drop rapidly due to the drop of the AC...

AI Technical Summary

Problems solved by technology

Changing the control strategy mainly realizes the reduction of input power through frequency-up method or step-down method, but with the up-frequency method, it takes a certain time for the wind turbine to detect the frequency change, and the fault ride-through effect is not good; with the step-down method, when a serious fault occurs When the AC voltage is close to 0, the operation of the wind turbine will be affected, so it has not been widely used in engineering

In engineering, DC energy consumption devices are mainly used to realize fault ride-through, but the energy consumption devices have large capacity and long investment time, resulting in high cost

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