Method and device for calculating short-circuit current in whole low-voltage ride through process of doubly-fed fan

Abstract

The invention discloses a method and a device for calculating short-circuit current in the whole low-voltage ride through process of a doubly-fed fan. The method comprises the following steps: determining a short-circuit current output to a power grid by a doubly-fed fan when the power grid has a short-circuit fault and the doubly-fed fan is in a Crowbar input stage; determining short-circuit current output to the power grid by the doubly-fed fan when the power grid has a short-circuit fault and the doubly-fed fan is in an RSC reactive power control stage; and determining the maximum short-circuit current and the minimum short-circuit current output to the power grid by the doubly-fed fan in the whole low-voltage ride-through process when the power grid has a short-circuit fault, wherein the maximum short-circuit current and the minimum short-circuit current are used for determining setting of related protection constant values in the power grid to which the doubly-fed fan is connected. The method comprehensively and completely considers the whole low-voltage ride-through process of the doubly-fed induction generator when the power grid is short-circuited, the calculated short-circuit current value is accurate and reliable, and the method is well matched with the actual operation process of the doubly-fed induction generator.

Description

technical field [0001] The invention belongs to the technical field of relay protection setting calculation, and in particular relates to a short-circuit current calculation method and device in the whole process of low-voltage ride-through of a double-fed fan. Background technique [0002] my country's wind energy resources are mainly distributed in the "Three Norths" and the southeast coastal areas, far away from the load center. At present, wind power generation has changed from small-scale and decentralized access in the early stage of development to cluster development and centralized grid connection. As a large number of wind farms are connected to the grid in the form of clusters, the impact of large-scale wind power access on the power system cannot be ignored. [0003] Field operation data show that in some areas where wind farm clusters are connected, when a short-circuit fault occurs in the power grid, the wind farm side provides a large short-circuit current to ...

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Problems solved by technology

[0005] In order to overcome the above-mentioned deficiencies in the prior art, the present invention provides a method and device for calculating the short-circuit current in the whole process of low-voltage ride-through of double-fed wind turbines, so as to improve the protection in the power grid caused by the inaccurate modeling of the short-circuit current of double-fed wind turbines in the current power grid protection setting calculation. The problem of insufficient accuracy of the setting value of

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