Differential protection configuration method and device for sending transformer out of double-feed type wind field

Abstract

The embodiment of the invention provides a differential protection configuration method and device for sending a transformer out of a double-feed type wind field. The method comprises the steps that the line current of the two sides of the transformer and the primary side phase voltage of the transformer are measured; the effective value, the differential current and the braking current of the current on the two sides of the transformer are calculated according to the line current on the two sides of the transformer; the primary side line voltage of the transformer is calculated according to the primary side phase voltage; a differential current sudden change moment T1 and a line voltage sudden change moment T2 are calculated; whether the absolute value of the difference value of the T1 and the T2 is smaller than a preset threshold value or not is judged; when the absolute value of the difference value of the T1 and the T2 is smaller than the preset threshold value, whether a fault is an outer fault or an inner fault is judged according to the positions of the differential current and the braking current of the transformer on a rate differential feature line; if the inner fault occurs, the transformer with the inner fault is removed. By means of the method, whether the reason for occurrence of the differential current of the transformer is magnetizing rush current or the inner fault can be accurately and rapidly distinguished, and the phenomenon that the action of the transformer is delayed due to temporary shutting differential protection of the double-feed type wind field transformer is avoided.

Description

technical field [0001] The invention belongs to the field of electric power systems, relates to the technical field of differential protection for transformers sent out from wind farms, and in particular to a method and device for preventing delayed action of transformers due to the influence of non-power frequency components. Background technique [0002] Since the current doubly-fed wind turbine has been widely used in the field of new energy power generation, it will generate non-power frequency current different from the traditional synchronous power supply during the fault period, which will lead to the current widely used in transformer protection. Misjudgment of the second harmonic braking principle will temporarily block the differential protection, thereby affecting the quick action of the transformer protection. The solution to the above-mentioned problems depends on an inrush current judging element with better performance. Therefore, it is of great theoretical a...

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Problems solved by technology

[0005] In the process of realizing the present invention, the inventor found that there are at least the following problems in the prior art: the solution of the prior art cannot prevent the delay action of the transformer due to the influence of non-power frequency components

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