Rapid discrimination method and system applied to doubly-fed wind power plant transmission transformer fault

Abstract

The invention relates to the technical field of relay protection of a power system, in particular to a method and a system for quickly judging faults of a double-fed wind power plant sending transformer, which comprises the following steps of: processing measured voltage and current instantaneous values of each side of the double-fed wind power plant sending transformer through a Butterworth filter, and then entering a differential current starting element for judging; comparing the differential current with a differential current starting setting value, if a starting criterion is met, entering a steady-state ratio differential protection judgment element, and judging whether the differential current is located in a steady-state high-value and low-value ratio differential protection action area or not; and according to the position of the differential current, the judgment of an auxiliary judgment element is executed, and the calculation and judgment of waveform amplitude characteristics and waveform distortion characteristics are carried out. The method has the advantages that the problem of transformer differential protection error locking caused by high harmonic content in the output short-circuit current of the double-fed wind power plant can be effectively solved, and it can be ensured that when the double-fed wind power plant breaks down, relevant faults can be rapidly and reliably removed.

Description

Technical Field

[0001] The present invention relates to the technical field of relay protection of electric power systems, and in particular to a method and system for quickly distinguishing faults of transmission transformers in a double-fed wind farm. Background Art

[0002] In the process of achieving the strategic goal of "dual carbon", new energy power generation gradually replaces traditional fossil energy power generation. Wind power generation, as an important part of new energy power generation, plays a vital role in promoting the transformation of the global energy structure and achieving the goals of "carbon peak and carbon neutrality". The booster transformer raises the output voltage of the doubly fed wind farm and then concentrates it into the high-voltage AC power grid. Therefore, in order to ensure the safe and stable operation of the doubly fed wind farm, the booster transformer needs to quickly and reliably cut off the fault when a fault occurs. At present, longitudinal current differential protection is the main protection method for booster transformers in doubly fed wind farms. Based on the principle of magnetic balance, this protection mechanism can theoretically provide absolute selectivity when a fault occurs inside the booster transformer, ensuring rapid and reliable action; in the event of an external fault, it can maintain the reliability of non-action. However, when the doubly-fed wind farm is connected to the AC grid-connected system, a low-resistance fault may occur inside the step-up transformer. At this time, the short-circuit current amplitude provided by the doubly-fed wind farm is limited and contains harmonic components, which will cause the second harmonic content in the differential current to no longer correspond to the core saturation, causing the transformer current transformer (TA) saturation discrimination element to malfunction and the excitation inrush current discrimination element to malfunction, causing the transformer differential protection to be mistakenly locked, which in turn causes the differential protection to have a delayed action problem, causing serious interference to the safe and stable operation of the power system. Summary of the invention

[0003] The purpose of this section is to summarize some aspects of embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot be used to limit the scope of the present invention.

[0004] In view of the above existing problems, the present invention is proposed.

[0005] Therefore, the present invention provides a method and system for quickly distinguishing faults of a transmission transformer in a doubly-fed wind farm, which can solve the problems mentioned in the background technology.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0007] In a first aspect, the present invention provides a method for quickly distinguishing faults of a doubly-fed wind farm transmission transformer, comprising: processing the obtained measured voltage and current instantaneous values ​​on each side of the doubly-fed wind farm transmission transformer through a Butterworth filter and then entering the differential current starting element for distinguishing;

[0008] Compare the differential current with the differential current start setting value. If the start criterion is met, the system enters the steady-state ratio differential protection discrimination element to determine whether the differential current is in the steady-state high-value or low-value ratio differential protection action area.

[0009] According to the differential current position, the auxiliary discrimination element is judged to calculate and judge the waveform amplitude characteristics and waveform distortion characteristics.

[0010] As a preferred solution of the method for quickly distinguishing faults of a transmission transformer in a doubly-fed wind farm according to the present invention, the differential current calculation includes:

[0011] Calculate the three-phase differential current of the output line transformer of the doubly-fed wind farm, including phases A, B, and C;

[0012] Compare the three-phase differential currents to obtain the maximum value, and compare the maximum value of the three-phase differential current with the differential current starting setting value. If the preset conditions are met, the protection is started.

[0013] As a preferred solution of the method for quickly distinguishing faults of a doubly-fed wind farm transmission transformer of the present invention, the steady-state ratio differential protection distinguishing comprises:

[0014] Conduct steady-state ratio differential protection identification;

[0015] If the differential current is in the differential quick-break action zone, it is determined to be an internal fault;

[0016] If the differential current is in the steady-state high-value ratio differential action area or the low-value ratio differential action area, it enters the auxiliary discrimination element, otherwise the discrimination ends.

[0017] As a preferred solution of the method for quickly distinguishing faults of a transmission transformer in a doubly-fed wind farm of the present invention, the auxiliary distinguishing element comprises:

[0018] Perform waveform amplitude feature discrimination and waveform distortion feature discrimination;

[0019] If the waveform amplitude characteristic is greater than the set value and the waveform distortion characteristic does not exceed the set interval, the auxiliary discrimination element meets the criteria.

[0020] As a preferred solution of the method for quickly distinguishing faults of a transmission transformer in a doubly-fed wind farm according to the present invention, the auxiliary distinguishing element judgment further includes:

[0021] If the calculated result of the waveform amplitude characteristic is greater than the set value, the flag Dir is set to 1, otherwise Dir is cleared;

[0022] If the calculated result of the waveform distortion characteristic is less than the set value, the flag is set to 1, otherwise the flag is cleared;

[0023] Perform an AND operation on the two flag bits Dir and Flag. If the operation result is 1, the auxiliary discrimination element meets the open condition.

[0024] As a preferred solution of the method for quickly distinguishing faults of a transmission transformer in a double-fed wind farm of the present invention, it further comprises: if the auxiliary criterion is continuous t set If the sampling points meet the requirement, it is determined as an in-zone fault;

[0025] If not satisfied, the inrush current determination element and TA saturation determination element will be used for judgment.

[0026] As a preferred solution of the method for quickly distinguishing faults of a transmission transformer in a doubly-fed wind farm of the present invention, inrush current distinguishing and TA saturation distinguishing include:

[0027] If the differential current is in the steady-state high-value ratio differential protection, the magnetizing inrush current is identified;

[0028] If the differential current is in the steady-state low-value ratio differential protection, the excitation inrush current judgment and TA saturation judgment are performed simultaneously.

[0029] In a second aspect, the present invention provides a rapid identification system for a double-fed wind farm transmission transformer fault, comprising: an acquisition processing module, for processing the acquired measured voltage and current instantaneous values ​​on each side of the double-fed wind farm transmission transformer through a Butterworth filter and then entering the differential current starting element for identification;

[0030] The comparison and judgment module is used to compare the differential current with the differential current starting setting value. If the starting criterion is met, the module enters the steady-state ratio differential protection discrimination element to determine whether the differential current is in the steady-state high-value and low-value ratio differential protection action area.

[0031] The execution calculation module is used to perform auxiliary discrimination element judgment according to the differential current position, and calculate and judge the waveform amplitude characteristics and waveform distortion characteristics.

[0032] In a third aspect, the present invention provides a computer device, including a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of the above method when executing the computer program.

[0033] In a fourth aspect, the present invention provides a computer-readable storage medium having a computer program stored thereon, which implements the steps of the above method when the computer program is executed by a processor.

[0034] Compared with the prior art, the beneficial effects of the present invention are as follows: it can effectively solve the problem of incorrect locking of transformer differential protection caused by high harmonic content in the output short-circuit current of the doubly-fed wind farm, and can ensure that the doubly-fed wind farm can quickly and reliably cut off the relevant faults when a fault occurs, thereby improving the stability and safety of the overall power system. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. Among them:

[0036] Figure 1 The figure is a schematic flow chart of a method for quickly distinguishing faults of a transmission transformer in a doubly-fed wind farm.

[0037] Figure 2 This is a schematic diagram of the structure of a typical new energy station transmission system.

[0038] Figure 3 It is the proportion of the second and third harmonics of the fault phase current flowing through the low-voltage side protection installation when a low-resistance fault occurs in the low-voltage side area of ​​the step-up transformer in the new energy station.

[0039] Figure 4 When an in-region fault or an out-of-region fault occurs on the high-voltage side of the step-up transformer at a new energy station, the auxiliary criterion of the present invention is used to calculate the curve of the waveform amplitude characteristic waveform.

[0040] Figure 5 When an in-region fault or an out-of-region fault occurs on the high-voltage side of the step-up transformer at a new energy station, the auxiliary criterion of the present invention is used to calculate the curve of the waveform distortion characteristic waveform.

[0041] Figure 6 A schematic diagram of the internal structure of a computer device. DETAILED DESCRIPTION

[0042] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings.

[0043] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0044] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0045] Example 1

[0046] Reference Figure 1 to Figure 5 , which is the first embodiment of the present invention, and provides a method for quickly distinguishing a fault of a transmission transformer in a doubly-fed wind farm, which comprises:

[0047] S1. The measured voltage and current instantaneous values ​​on each side of the output transformer of the doubly-fed wind farm are processed by a Butterworth filter and then enter the differential current starting element for identification.

[0048] It should be noted that the Butterworth filter can effectively remove unnecessary high-frequency noise or interference from the signal. The noise may come from environmental interference, electronic noise of the equipment itself, or errors in the measurement process. Furthermore, the parameters of the Butterworth filter are pre-set according to the actual operating frequency and damping characteristics of the doubly-fed wind farm output transformer.

[0049] Preferably, the Butterworth filter can provide a smooth frequency response compared to other types of filters, that is, at the cutoff frequency of the filter, the attenuation of the signal is very gradual without sudden changes, thereby avoiding the introduction of additional distortion in signal processing.

[0050] S2. Compare the differential current with the differential current starting setting value. If the starting criterion is met, enter the steady-state ratio differential protection judgment element to determine whether the differential current is in the steady-state high-value or low-value ratio differential protection action area.

[0051] Furthermore, the differential current calculation includes:

[0052] Calculate the three-phase differential current of the output line transformer of the doubly-fed wind farm, including phases A, B, and C;

[0053] Compare the three-phase differential currents to obtain the maximum value, and compare the maximum value of the three-phase differential current with the differential current starting setting value. If the preset conditions are met, the protection is started.

[0054] It should be noted that using the formula Calculate the three-phase differential current of the transmission line transformer of the doubly fed wind farm, φ is the three phases A, B, and C. Then compare the three-phase differential current to obtain its maximum value |I dφmax |, the maximum value of the three-phase differential current |I dφmax |With differential current starting setting value I cdqd For comparison, if |Idφmax |>I cdqd If satisfied, protection starts. 1φ......mφ are the currents on each side of the transformer, I dφ is the single-phase differential current, |I dφmax | is the maximum value of the three-phase differential current, I cdqd It is the differential current starting setting value.

[0055] Furthermore, the steady-state ratio differential protection discrimination includes:

[0056] Conduct steady-state ratio differential protection identification;

[0057] If the differential current is in the differential quick-break action zone, it is determined to be an internal fault;

[0058] If the differential current is in the steady-state high-value ratio differential action area or the low-value ratio differential action area, it enters the auxiliary discrimination element, otherwise the discrimination ends.

[0059] It should be noted that the formula Perform steady-state ratio differential protection judgment. If the differential current is in the differential quick-break action area, it is judged as an internal fault. If the differential current is in the steady-state high-value ratio differential action area or the low-value ratio differential action area, it enters the auxiliary judgment element, otherwise the judgment ends. Where: I e is the rated current of the transformer, I 1φ......mφ are the currents on each side of the transformer, I dφ is the single-phase differential current, I rφ is the single-phase braking current, φ is the three-phase A, B, and C, I cdqd is the steady-state ratio differential starting setting, K b1 is the ratio braking coefficient setting value (0.2≤K b1 ≤0.75), can be fixed at 0.5.

[0060] S3. According to the differential current position, the auxiliary discrimination element is used to perform the calculation and judgment of the waveform amplitude characteristics and the waveform distortion characteristics.

[0061] Furthermore, the auxiliary discrimination element determination includes:

[0062] Perform waveform amplitude feature discrimination and waveform distortion feature discrimination;

[0063] If the waveform amplitude characteristic is greater than the set value and the waveform distortion characteristic does not exceed the set interval, the auxiliary discrimination element meets the criteria.

[0064] It should be noted that using the formula To identify the waveform amplitude characteristics, and use the formula To identify the waveform distortion characteristics, When a fault occurs in the boost transformer area of ​​a doubly-fed wind farm, due to the weak-feed characteristics of the fault current of the doubly-fed wind farm, there is a significant difference in the amplitude characteristics of the current flowing through the high- and low-voltage side protection installations of the transformer. After being processed by the waveform amplitude characteristic discrimination element, the result will be significantly greater than the setting value. At the same time, due to the current-limited characteristics of the new energy power supply, its fault current is difficult to cause the current transformer to enter the saturation area, the interruption angle is small, and the interruption time is short. After being processed by the waveform distortion characteristic discrimination element, the result does not exceed the setting interval. When an out-of-area fault occurs, the short-circuit currents on the high- and low-voltage sides are both provided by traditional power supplies or doubly-fed wind farms. There is no obvious difference between the short-circuit currents on the high- and low-voltage sides. Using the formula for processing, the waveform amplitude characteristics are much smaller than the setting value. When the short-circuit current is provided by a traditional power supply, the short-circuit current is large, which will cause the current transformer (TA) to saturate, the interruption angle is large, and the interruption time is long. Using the formula for processing, the waveform distortion characteristics significantly exceed the setting value. Where: I lφ is the current flowing through the low-voltage side protection installation of the transformer in the short window, I hφ It is the current flowing through the high voltage side protection installation of the transformer in the short window. is the rated current amplitude of the transformer, is the waveform discontinuity angle, t 1 is the duration of waveform interruption.

[0065] Furthermore, the auxiliary discrimination element determination also includes:

[0066] If the calculated result of the waveform amplitude characteristic is greater than the set value, the flag Dir is set to 1, otherwise Dir is cleared;

[0067] If the calculated result of the waveform distortion characteristic is less than the set value, the flag is set to 1, otherwise the flag is cleared;

[0068] Perform an AND operation on the two flag bits Dir and Flag. If the operation result is 1, the auxiliary discrimination element meets the open condition.

[0069] Furthermore, it also includes: if the auxiliary criterion is continuous t set If the sampling points meet the requirement, it is determined as an in-zone fault;

[0070] If not satisfied, the inrush current determination element and TA saturation determination element will be used for judgment.

[0071] It should be noted that the two flags Dir and Flag are ANDed. If the result is 1, the auxiliary discrimination element meets the open condition. set If a sampling point meets the opening condition, it is judged as an in-zone fault; if the result is 0, the auxiliary discrimination element does not meet the opening condition, and the inrush current discrimination element and the TA saturation element are entered.

[0072] Furthermore, the inrush current determination and TA saturation determination include:

[0073] If the differential current is in the steady-state high-value ratio differential protection, the magnetizing inrush current is identified;

[0074] If the differential current is in the steady-state low-value ratio differential protection, the excitation inrush current judgment and TA saturation judgment are performed simultaneously.

[0075] It should be noted that if the auxiliary criterion is not met and the differential current is in the steady-state high-value ratio differential action area, the formula If all three phases satisfy the above equation, the inrush current discrimination element satisfies the open regulation, and the continuous t set If the sampling points meet the open condition, it is judged as an internal fault; if one of the three phases does not meet the above equation, the judgment is terminated. 2nd ,I 3nd are the second harmonic and third harmonic in each phase differential current respectively. 1st k is the fundamental wave of the differential current of the corresponding phase. 2xb , k 3xb They are the setting values ​​of the second harmonic and third harmonic braking coefficients respectively. 2xb Fixed to 0.15, k 3xb Fixed at 0.2.

[0076] It should be further explained that if the auxiliary criterion is not met and the differential current is in the steady-state low-value ratio differential action area, the formulas Conduct magnetizing inrush current identification and formula If the three phases satisfy the above two sets of equations, that is, the inrush current discrimination element and the TA saturation discrimination element meet the open conditions, the continuous t set If the sampling points meet the opening conditions, it is judged as an internal fault. If the three phases do not fully meet the above two sets of equations, that is, the inrush current discrimination element and the TA saturation discrimination element do not fully meet the opening conditions, the discrimination is terminated. 2nd ,I 3nd are the second harmonic and third harmonic in each phase differential current respectively. 1st k is the fundamental wave of the differential current of the corresponding phase. 2xb , k 3xb They are the setting values ​​of the second harmonic and third harmonic braking coefficients respectively. 2xb Fixed to 0.15, k 3xb Fixed to 0.2, I φ2 is the second harmonic in the phase current, I φ3 is the third harmonic in the phase current, I φ1 is the fundamental wave in the phase current, φ is the three phases A, B, and C, k φ2xb and k φ3xb is a certain proportional constant. In this embodiment, k is taken φ2xbis 0.15. In this embodiment, k φ3xb is 0.2. In this embodiment, t set is 10.

[0077] In a specific embodiment, the transformer low-voltage side F3 is set to have an internal fault, and the transformer low-voltage side F4 is set to have an external fault. The direction criterion of the present invention is used, and the curve of the waveform amplitude characteristic calculation result and time is as follows: Figure 4 At this time, the calculated result of the waveform amplitude characteristic outside the zone is much larger than the set value (indicating that the amplitude of the fault current exceeds the expected value during normal operation), and the calculated result of the waveform amplitude characteristic inside the zone is significantly smaller than the set value (indicating that the amplitude of the fault current is actually larger in the case of an out-of-zone fault, but due to the role of the direction criterion, the system can correctly identify that this is an out-of-zone fault).

[0078] In summary, the beneficial effect of the rapid identification method of the transmission transformer fault applied to the doubly fed wind farm of the present invention is that it can effectively solve the problem of incorrect locking of the transformer differential protection caused by the high harmonic content in the output short-circuit current of the doubly fed wind farm, and can ensure that the doubly fed wind farm can quickly and reliably cut off the relevant faults when a fault occurs, thereby improving the stability and safety of the overall power system.

[0079] Example 2

[0080] This embodiment provides a rapid identification system for a double-fed wind farm transmission transformer fault, which includes an acquisition processing module for processing the acquired measured voltage and current instantaneous values ​​on each side of the double-fed wind farm transmission transformer through a Butterworth filter and then entering the differential current starting element for identification;

[0081] The comparison and judgment module is used to compare the differential current with the differential current starting setting value. If the starting criterion is met, the module enters the steady-state ratio differential protection discrimination element to determine whether the differential current is in the steady-state high-value and low-value ratio differential protection action area.

[0082] The execution calculation module is used to perform auxiliary discrimination element judgment according to the differential current position, and calculate and judge the waveform amplitude characteristics and waveform distortion characteristics.

[0083] The above-mentioned unit modules may be embedded in or independent of a processor in a computer device in the form of hardware, or may be stored in a memory in a computer device in the form of software, so that the processor can call and execute operations corresponding to the above-mentioned modules.

[0084] Example 3

[0085] This embodiment provides a computer device, which may be a terminal, and its internal structure diagram may be as follows: Figure 6As shown. The computer device includes a processor, a memory, a communication interface, a display screen and an input device connected through a system bus. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The communication interface of the computer device is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner can be achieved through WIFI, an operator network, NFC (near field communication) or other technologies. When the computer program is executed by the processor, a rapid judgment method for faults of a transmission transformer in a double-fed wind farm is implemented. The display screen of the computer device can be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer device can be a touch layer covered on the display screen, or a key, trackball or touchpad set on the computer device housing, or an external keyboard, touchpad or mouse, etc.

[0086] The present embodiment also provides a computer-readable storage medium on which a computer program is stored. When the computer program is executed by a processor, the following is achieved: the measured voltage and current instantaneous values ​​on each side of the doubly-fed wind farm transmission transformer are obtained and processed by a Butterworth filter before entering the differential current starting element for discrimination; the differential current is compared with the differential current starting setting value, and if the starting criterion is met, the steady-state ratio differential protection discrimination element is entered to determine whether the differential current is located in a steady-state high-value and low-value ratio differential protection action zone; according to the differential current position, the auxiliary discrimination element is executed to calculate and determine the waveform amplitude characteristics and waveform distortion characteristics.

[0087] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A rapid identification method for a transmission transformer fault in a doubly-fed wind farm, characterized in that: include, The measured voltage and current instantaneous values ​​on each side of the output transformer of the double-fed wind farm are processed by the Butterworth filter and then enter the differential current starting element for identification; Compare the differential current with the differential current start setting value. If the start criterion is met, the system enters the steady-state ratio differential protection discrimination element to determine whether the differential current is in the steady-state high-value or low-value ratio differential protection action area. According to the differential current position, the auxiliary discrimination element is judged to calculate and judge the waveform amplitude characteristics and waveform distortion characteristics.

2. The rapid identification method for a double-fed wind farm transmission transformer fault according to claim 1, characterized in that: The differential current calculation includes: Calculate the three-phase differential current of the output line transformer of the doubly-fed wind farm, including phases A, B, and C; Compare the three-phase differential currents to obtain the maximum value, and compare the maximum value of the three-phase differential current with the differential current starting setting value. If the preset conditions are met, the protection is started.

3. The rapid identification method for a double-fed wind farm transmission transformer fault as claimed in claim 2 is characterized in that: The steady-state ratio differential protection discrimination includes: Conduct steady-state ratio differential protection identification; If the differential current is in the differential quick-break action zone, it is determined to be an internal fault; If the differential current is in the steady-state high-value ratio differential action area or the low-value ratio differential action area, it enters the auxiliary discrimination element, otherwise the discrimination ends.

4. The rapid fault identification method for a doubly-fed wind farm transmission transformer according to any one of claims 1 to 3, characterized in that: The auxiliary discrimination element judgment comprises: Perform waveform amplitude feature discrimination and waveform distortion feature discrimination; If the waveform amplitude characteristic is greater than the set value and the waveform distortion characteristic does not exceed the set interval, the auxiliary discrimination element meets the criteria.

5. The rapid identification method for a transmission transformer fault in a double-fed wind farm as claimed in claim 4 is characterized in that: The auxiliary discrimination element judgment also includes: If the calculated result of the waveform amplitude characteristic is greater than the set value, the flag Dir is set to 1, otherwise Dir is cleared; If the calculated result of the waveform distortion characteristic is less than the set value, the flag is set to 1, otherwise the flag is cleared; Perform an AND operation on the two flag bits Dir and Flag. If the operation result is 1, the auxiliary discrimination element meets the open condition.

6. The rapid identification method for a transmission transformer fault in a double-fed wind farm as claimed in claim 5, characterized in that: Also includes: If the auxiliary criterion is continuous t set If the sampling points meet the requirement, it is determined as an in-zone fault; If not satisfied, the inrush current determination element and TA saturation determination element will be used for judgment.

7. The rapid identification method for a transmission transformer fault in a double-fed wind farm as claimed in claim 6, characterized in that: The inrush current determination and TA saturation determination include: If the differential current is in the steady-state high-value ratio differential protection, the magnetizing inrush current is identified; If the differential current is in the steady-state low-value ratio differential protection, the excitation inrush current judgment and TA saturation judgment are performed simultaneously.

8. A rapid fault identification system for a doubly-fed wind farm transmission transformer, characterized in that: include: The acquisition processing module is used to process the acquired measured voltage and current instantaneous values ​​of each side of the double-fed wind farm output transformer through a Butterworth filter and then enter the differential current starting element for identification; The comparison and judgment module is used to compare the differential current with the differential current starting setting value. If the starting criterion is met, the module enters the steady-state ratio differential protection discrimination element to determine whether the differential current is in the steady-state high-value and low-value ratio differential protection action area. The execution calculation module is used to perform auxiliary discrimination element judgment according to the differential current position, and calculate and judge the waveform amplitude characteristics and waveform distortion characteristics.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 7 are implemented.

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