Fault ride-through method and system for wind power delivery system of flexible DC power grid

Abstract

The invention provides a fault ride-through method and system for a wind power delivery system of a flexible DC power grid. The method includes the following steps: when a flexible DC power grid malfunctions, a flexible DC converter station locks a fault level on the basis of a detected voltage fault type and sends an active control demand to a wind electric field, and the wind electric field enables active power of a wind turbine generator to be locked urgently on the basis of the control demand of the active power; when faults of the flexible DC power grid are removed, the flexible DC converter station restarts the fault level and controls tripping of the wind turbine generator on the basis of conveying capabilities of the flexible DC power grid after the faults occur, active power output of the wind turbine generator that stays in a grid-connected operating condition and stays in a power locked state is restored, and thus fault ride-through is completed. The fault level converter station is locked after the DC power grid malfunctions, and the wind turbine generator unlocks converters after the faults are removed, thereby ensuring that the flexible DC power grid will not run overload. Moreover, it can be judged that part of the wind turbine generator needs to be cut off, active power output of the grid-connected wind turbine generator is restored, and then fault ride-throughis completed.

Description

technical field [0001] The invention relates to the field of electrical technology, in particular to a fault ride-through method and system for a wind power transmission system of a flexible direct current grid. Background technique [0002] Long-distance transmission without synchronous power support when large-scale wind power islands are connected to the grid will become one of the main ways of wind power consumption in the future. As a power source based on power electronics technology, wind turbines are limited by the lack of inertia of power electronic equipment, weak overload capacity, and poor ability to resist grid disturbances. state response characteristics. [0003] Wind power has the characteristics of randomness and intermittentness. Without the support of sufficient synchronous power sources, traditional power transmission methods are difficult to meet the requirements of long-distance transmission of large-scale wind power. However, flexible DC transmission ...

AI Technical Summary

Problems solved by technology

When the power transmission capacity of the converter station decreases due to a fault in the flexible DC grid, if the converter station does not change the control strategy, it is difficult for the wind turbine to sense the fault in time and still generate active power according to normal operation. Due to the response time of the flexible DC grid At the ms level, under the premise that the protection is too late to act, the converter station of the flexible DC grid is overloaded

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