Method for improving failure recovery characteristics of large-scale wind electricity through direct current outgoing system

Abstract

The invention provides a method for improving failure recovery characteristics of large-scale wind electricity through a direct current outgoing system. The method comprises the following steps of (1) judging whether an alternating current power grid has earth faults, conducting a step (2) on yes judgment, and repeating the step (1) on no judgment; (2) judging whether wind power is reduced or not, conducting a step (3) on yes judgment, and returning to the step (1) on no judgment; (3) changing power instruments of a direct current system and enabling direct current power instructions to change along with changes of the wind power; and (4) increasing direct current power tracking if the wind power continuously increases, or control is stopped. The method for improving the failure recovery characteristics of the large-scale wind electricity through the direct current outgoing system enables the large-scale wind electricity to be connected in a power grid through direct current, changes characteristics of a traditional power grid, improves after-fault power grid voltage recovery capability through a direct current power tracking and controlling method, and improves recovery characteristics of the large-scale wind electricity through the direct current outgoing system.

Description

technical field [0001] The invention belongs to the field of electric power systems, and in particular relates to a method for improving the fault recovery characteristics of a large-scale wind power transmission system via direct current. Background technique [0002] According to the power grid plan, by 2015, the installed capacity of wind power in Gansu (Jiuquan) in Northwest China will reach 12,710MW, and the Jiuquan-Hunan ±800kV DC transmission project will also be completed, with a transmission capacity of 8,000MW, and 3,788MW wind turbines will pass through Qiaowan 750kV The power station is connected to the grid. In the large-scale wind power transmission system via DC, when a short-circuit fault occurs on the AC line, the voltage drops rapidly and the wind turbine enters the low voltage ride-through process. During this period, the double-fed variable-speed wind turbine absorbs a large amount of reactive power, causing a serious voltage drop. . After the fault is ...

AI Technical Summary

Problems solved by technology

According to the existing DC control and protection strategy, after a fault occurs, the DC power quickly recovers to the rated operation after being disturbed, but the wind power has not yet recovered, and the output of the power grid at the sending end decreases, resulting in a decrease in system frequency and grid voltage.

At the same time, the DC system absorbs a large amount of reactive power during the recovery period, which aggravates the drop of the grid voltage

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