Current trend feature-based ct wire breakage identification method and device, and electronic equipment

Abstract

The application discloses a kind of based on current trend feature's fast CT broken line identification method, including the following steps: the branch current used by differential protection is collected, and the amplitude of each sampling point is calculated;According to the amplitude of each sampling point, its current following value is calculated and compared, to judge current change trend;When differential protection starts, by judging current change trend, if there is branch current drop, and no other branch current appears rise, then the branch of branch drop is judged as broken line branch, and differential protection is locked out.The application adopts tracking current change trend to quickly identify current change, can effectively realize the fast and accurate identification of CT broken line under the condition that system load change is more frequent, prevent differential protection misoperation caused by CT broken line.

Description

Technical Field

[0001] This application belongs to the field of power system relay protection, and specifically relates to a fast CT disconnection identification method, device and electronic equipment based on current trend characteristics. Background Technology

[0002] In the field of relay protection, when a current transformer (CT) in a branch that is included in the differential current calculation experiences a CT disconnection, a differential current will be generated, which may lead to malfunction of the differential protection function. Therefore, a fast CT disconnection identification method is needed to identify the CT disconnection before the differential protection function malfunctions and to lock out the differential protection.

[0003] Detecting rapid CT disconnection requires determining whether the current in each phase decreases from a large value. A straightforward approach is to subtract the current from the current at a previous moment; if the difference is negative and its absolute value exceeds a set fixed threshold, the current is considered to have decreased. However, this method suffers from the limitation that the pre-set fixed threshold cannot accommodate the changing characteristics of branches with varying current magnitudes when a disconnection occurs. Furthermore, existing technologies compare current changes with amplitudes from several cycles ago. For example, CN105467264B, "A Rapid Identification Method for CT Disconnection Based on Three-Half Connection Busbar Protection," uses current from four cycles ago; and CN107069673B, "A Method for Rapidly Identifying Branch CT Disconnection and Blocking Bus Differential Protection," uses current from the first two cycles. These methods employ relatively long current time windows, which cannot accurately reflect instantaneous current changes under conditions of frequent system load variations, thus affecting the accuracy of rapid CT disconnection detection.

[0004] Based on the above analysis, it is necessary to consider a method that can track changes in current trends and quickly identify CT disconnections through calculation of real-time sampled data, thereby improving the adaptability of rapid CT disconnection identification to various operating conditions of the power system. Summary of the Invention

[0005] This application aims to provide a fast CT disconnection identification method based on current trend characteristics. By calculating the current follow-up value by the current amplitude and comparing it, the method tracks the current change trend, which can effectively realize the fast and accurate identification of CT disconnection under the condition of frequent system load changes, and prevent the differential protection function from malfunctioning.

[0006] According to one aspect of this application, a fast CT line breakage identification method based on current trend characteristics is provided, comprising:

[0007] Step 1: Collect the current of each branch used by the differential protection, and calculate the current amplitude x at each sampling point of each branch. n_ph_LWhere n is the nth sampling point, ph is the current phase, including three phases A, B, and C; and L is the Lth branch.

[0008] Step 2: Based on the current amplitude x at the sampling point n_ph_L Calculate the corresponding current follower value x n_ph_L_follow ;

[0009] Step 3: Compare the current amplitude at the sampling point with its corresponding current tracking value to determine the current change trend at the sampling point;

[0010] Step 4: After the differential protection is activated, the current change trend of each branch's M consecutive sampling points is judged. If the current change trend of a branch's M consecutive sampling points all increase, the current of that branch is determined to be increasing. If the current change trend of a branch's M consecutive sampling points all decrease, the current of that branch is determined to be decreasing. If no branch current shows an increasing trend, the branch with decreasing current is judged to be a CT disconnection branch, and the differential protection is blocked. If a branch current shows an increasing trend, it is judged that no CT disconnection has occurred, and the differential protection is not blocked.

[0011] According to some embodiments, the method for calculating the current amplitude in step 1 is as follows:

[0012]

[0013] Where ph represents the current phase, including three phases A, B, and C; L represents the Lth branch; x n_ph_L x represents the current amplitude of phase ph in branch L at time n; n_ph_L_sample Let N be the current sample value of phase ph at sampling point n in branch L; N is the number of sampling points per cycle.

[0014] According to some embodiments, the current follower value x in step 2 n_ph_L_follow The calculation methods include:

[0015] Step 2.1: Calculate the difference between the current amplitude at sampling point n and the current following value at the previous sampling point n-1 to obtain the first difference value x. n_ph_L_diff =x n_ph_L -x (n-1)_ph_L_follow ;where x (n-1)_ph_L_follow The current following value is the current following value corresponding to sampling point n-1, and the initial current following value is x. 0_ph_L_follow Set to 0;

[0016] Step 2.2: Calculate the first difference x n_ph_L_diff The cumulative sum of amplitude differences is calculated as follows: x n_ph_L_diff_add =x (n-1)_ph_L_diff_add +x n_ph_L_diff , where x n_ph_L_diff_addx is the accumulated value of the amplitude difference corresponding to sampling point n. (n-1)_ph_L_diff_add This is the accumulated amplitude difference value corresponding to the previous sampling point n-1. The initial value of the accumulated amplitude difference value at sampling point 0 is set to 0.

[0017] Step 2.3: If x n_ph_L_diff_add If the value is positive, it indicates that the current is gradually increasing. The sum of the amplitude differences at sampling point n is divided by the first coefficient k1, and then added to the current following value of the previous sampling point n-1. This gives the current following value for sampling point n. The calculation method is as follows:

[0018] If x n_ph_L_diff_add If the value is negative, it indicates that the current is gradually decreasing. The accumulated amplitude difference at sampling point n is divided by the second coefficient k2, and then added to the current following value from the previous sampling point n-1. This gives the current following value for sampling point n. The calculation method is as follows:

[0019] According to some embodiments, step 2.2 further includes:

[0020] If x n_ph_L_diff With x (n-1)_ph_L_diff_add The product of x and y is negative, indicating that the current trend has changed at sampling point n. In this case, x... (n-1)_ph_L_diff_add If we clear the values ​​to zero, then the cumulative difference between the n sample points is: x n_ph_L_diff_add =x (n-1)_ph_L_diff_add +x n_ph_L_diff =x n_ph_L_diff .

[0021] According to some embodiments, step 2.3 further includes the first coefficient k1 and the second coefficient k2 having values ​​ranging from 2 to 10.

[0022] According to some embodiments, step 3 further includes: when the amplitude of the sampling point is less than the corresponding current follower value, it is determined that the current at the sampling point is trending downwards; when the amplitude of the sampling point is greater than the corresponding current follower value, it is determined that the current at the sampling point is trending upwards.

[0023] According to some embodiments, the method for determining the current change trend in step 3 is as follows: if x n_ph_L <x n_ph_L_follow -k3, then it is determined that the current at that sampling point is trending downwards; if x n_ph_L >x n_ph_L_follow If +k4, then the current at that sampling point is determined to be increasing.

[0024] Where k3 and k4 are fixed thresholds, and the values ​​of k3 and k4 range from 0.04 to 0.1I. n I n This is the secondary rated current value.

[0025] According to some embodiments, step 4 further includes: after the differential protection is started, by judging the current change trend of M consecutive sampling points, if there is an increase in a branch, it is judged that no CT disconnection has occurred, and the differential protection is not blocked; wherein, the value range of M is M≥4.

[0026] According to another aspect of this application, a device for rapid CT line breakage identification based on current trend characteristics is provided, comprising:

[0027] The sampling module is used to collect the current of each branch used by the differential protection and to calculate the current amplitude x at each sampling point of each branch. n_ph_L Where n is the nth sampling point, ph is the current phase, including three phases A, B, and C; and L is the Lth branch.

[0028] The current follower value calculation module is used to calculate the current amplitude x based on the sampling point. n_ph_L Calculate the corresponding current follower value x n_ph_L_follow ;

[0029] The comparison module is used to compare the current amplitude of each sampling point with its corresponding current tracking value to determine the current change trend of the sampling point.

[0030] The identification module is used to determine the current change trend of each branch's M consecutive sampling points output by the comparison module after the differential protection is activated. If the current change trend of a branch's M consecutive sampling points all increase, the branch current is determined to be increasing; if the current change trend of a branch's M consecutive sampling points all decrease, the branch current is determined to be decreasing. If no branch current shows an increasing trend, the branch with decreasing current is determined to be a CT disconnection branch, and the differential protection is blocked. If a branch current shows an increasing trend, it is determined that no CT disconnection has occurred, and the differential protection is not blocked.

[0031] According to another aspect of this application, an electronic device is provided, comprising:

[0032] A processor; a memory; and a computer program stored in the memory and executable on the processor, wherein the processor, when executing the computer program, implements the method described in any one of the above methods.

[0033] This application provides a fast CT disconnection identification method based on current trend characteristics. It tracks the current change trend by calculating the current follow-up value by the current amplitude and comparing it. This method adapts to frequent changes in system load and shortens the time window required for CT disconnection identification. It can quickly and effectively achieve accurate identification of CT disconnection under operating conditions with frequent changes in system load, and prevent the differential protection function from malfunctioning due to CT disconnection. Attached Figure Description

[0034] Figure 1 A flowchart is shown below illustrating a fast CT disconnection identification method based on current trend characteristics according to an example embodiment of this application;

[0035] Figure 2 A flowchart is shown for yet another fast CT disconnection identification method based on current trend characteristics provided in an example embodiment of this application;

[0036] Figure 3 A flowchart is shown illustrating a method for calculating current follower values ​​according to an example embodiment of this application;

[0037] Figure 4 A block diagram of an apparatus for rapid CT line disconnection identification based on current trend characteristics according to an example embodiment of this application is shown.

[0038] Figure 5 A block diagram of an electronic device according to an exemplary embodiment is shown. Detailed Implementation

[0039] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein; rather, they are provided so that this application will be thorough and complete, and will fully convey the concept of the exemplary embodiments to those skilled in the art. The same reference numerals in the drawings denote the same or similar parts, and therefore repeated descriptions of them will be omitted.

[0040] Furthermore, the described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. Numerous specific details are provided in the following description to give a thorough understanding of embodiments of this application. However, those skilled in the art will recognize that the technical solutions of this application can be practiced without one or more of the specific details, or other methods, components, apparatuses, steps, etc., can be employed. In other instances, well-known methods, apparatuses, implementations, or operations are not shown or described in detail to avoid obscuring various aspects of this application.

[0041] The block diagrams shown in the accompanying drawings are merely functional entities and do not necessarily correspond to physically independent entities. That is, these functional entities can be implemented in software, in one or more hardware modules or integrated circuits, or in different network and / or processor devices and / or microcontroller devices.

[0042] The flowcharts shown in the accompanying drawings are merely illustrative and do not necessarily include all content and operations / steps, nor do they necessarily have to be performed in the described order. For example, some operations / steps can be broken down, while others can be combined or partially combined; therefore, the actual execution order may change depending on the specific circumstances.

[0043] It should be understood that although the terms first, second, third, etc., may be used herein to describe various components, these components should not be limited by these terms. These terms are used to distinguish one component from another. Therefore, the first component discussed below may be referred to as the second component without departing from the teachings of this application. As used herein, the term "and / or" includes all combinations of any one and more of the associated listed items.

[0044] Those skilled in the art will understand that the accompanying drawings are merely schematic diagrams of exemplary embodiments, and the modules or processes in the drawings are not necessarily essential for implementing this application, and therefore cannot be used to limit the scope of protection of this application.

[0045] The technical solutions of this application will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0046] Figure 1 The flowchart illustrates a fast CT disconnection identification method based on current trend characteristics according to an example embodiment of this application. The method includes the following steps:

[0047] S110: Collect the current of each branch used by the differential protection and calculate the current amplitude x at each sampling point of each branch current. n_ph_L Where n is the nth sampling point, ph is the current phase, including three phases A, B, and C; and L is the Lth branch.

[0048] S120: Current amplitude x based on the sampling point n_ph_L Calculate the corresponding current follower value x n_ph_L_follow ;

[0049] S130: Based on the comparison between the current amplitude of the sampling point and its corresponding current tracking value, determine the current change trend of the sampling point;

[0050] S140: After the differential protection is activated, the current change trend of M consecutive sampling points of each branch is judged. If the current change trend of M consecutive sampling points of a certain branch increases, the current of that branch is determined to be increasing. If the current change trend of M consecutive sampling points of a certain branch decreases, the current of that branch is determined to be decreasing. If no branch current shows an increasing trend, the branch with decreasing current is judged to be a CT disconnection branch, and the differential protection is blocked. If there is a branch current showing an increasing trend, it is judged that no CT disconnection has occurred, and the differential protection is not blocked.

[0051] Figure 2 The flowchart illustrates another fast CT disconnection identification method based on current trend characteristics according to an example embodiment of this application. The method includes the following steps:

[0052] S210: Collect the current of each branch used by the differential protection and calculate the amplitude of each sampling point of the current of each branch;

[0053] Preferably, the method for calculating the current amplitude in S210 is as follows:

[0054]

[0055] Where ph represents the current phase, including three phases A, B, and C; L represents the Lth branch; x n_ph_L x represents the current amplitude of phase ph in branch L at time n; n_ph_L_sample Let N be the current sample value of phase ph at sampling point n in branch L; N is the number of sampling points per cycle.

[0056] S220: Calculate the current tracking value x based on the amplitude of the current at each sampling point of each branch. n_ph_L_follow The calculation method for the current follower value is based on Figure 3 Provide a detailed description;

[0057] S230: Compare the amplitude of each sampling point with its corresponding current tracking value to determine the current change. The determination method is as follows: If x n_ph_L <x n_ph_L_follow -k3, then it is determined that the current at that sampling point is trending downwards; if x n_ph_L >x n_ph_L_follow If +k4 is used, the current at the sampling point is determined to be increasing; k3 and k4 are fixed thresholds to prevent misjudgment of the current trend due to normal current fluctuations.

[0058] Among them, the fixed thresholds k3 and k4 are set to 0.04I. n .

[0059] S240: After the differential protection is started, based on the current change trend of each branch participating in the differential protection calculation obtained in steps S210 to S230, the current trend of four consecutive sampling points is judged. If no branch current shows an increasing trend, the branch with decreasing branch current is judged as the CT disconnection branch, and the differential protection is blocked; if there is a branch current showing an increasing trend, it is judged that no CT disconnection has occurred, and the differential protection is not blocked.

[0060] Figure 3 A flowchart is shown below illustrating a method for calculating a current follower value according to an example embodiment of this application. The method includes the following steps:

[0061] S301: When the sampling point is n=1, calculate the difference x between the current amplitude at the current sampling point n and the current following value at the previous sampling point n-1. n_ph_L_diff =x n_ph_L -x (n-1)_ph_L_follow x 0_ph_L_follow =0;

[0062] S302: x n_ph_L_diff As an accumulated value, it is recorded in x n_ph_L_diff_add The calculation method is as follows: x n_ph_L_diff_add =x (n-1)_ph_L_diff_add +x n_ph_L_diff ;

[0063] Where, x 0_ph_L_diff_add The cumulative value of the amplitude difference at the 0 sampling point is set to 0;

[0064] S303: If x n_ph_L_diff_add If the value is positive, it indicates that the current is gradually increasing. The current following value of the current sampling point n is obtained by dividing the cumulative value of the amplitude difference at the current sampling point n by the set coefficient k1 and adding the current following value of the previous sampling point n-1. The calculation method is as follows: If x n_ph_L_diff_add If the value is negative, it indicates that the current is gradually decreasing. The current following value of the current sampling point is obtained by dividing the cumulative value of the amplitude difference at the current sampling point n by the set coefficient k2 and adding the current following value of the previous sampling point n-1. The calculation method is as follows: If x n_ph_L_diff With x (n-1)_ph_L_diff_add The product of x and y is negative, so x is... (n-1)_ph_L_diff_add Reset to zero, then x n_ph_L_diff_add =x n_ph_L_diff ;

[0065] The coefficients k1 and k2 are set to 2.

[0066] S304, the next sampling point n = n + 1, repeat steps S301 to S303.

[0067] The following describes an apparatus embodiment of this application, which can be used to perform the method embodiment of this application. For details not disclosed in the apparatus embodiment of this application, please refer to the method embodiment of this application.

[0068] Figure 4 A block diagram of an apparatus for rapid CT line breakage identification based on current trend characteristics according to an example embodiment of this application is shown.

[0069] Figure 4 The device shown can perform the aforementioned method for rapid CT line breakage identification based on current trend characteristics according to the embodiments of this application.

[0070] like Figure 4 As shown, the device for rapid CT line breakage identification based on current trend characteristics may include: a sampling module 410, a current follower value calculation module 420, a comparison module 430, and an identification module 440.

[0071] See Figure 4 And referring to the preceding description,

[0072] The sampling module 410 is used to collect the current of each branch used by the differential protection and to calculate the current amplitude x at each sampling point of each branch current. n_ph_L Where n is the nth sampling point, ph is the current phase, including three phases A, B, and C; and L is the Lth branch.

[0073] The current follower value calculation module 420 is used to calculate the current amplitude x based on the sampling point. n_ph_L Calculate the corresponding current follower value x n_ph_L_follow ;

[0074] The comparison module 430 is used to compare the current amplitude of each sampling point with its corresponding current tracking value to determine the current change trend of the sampling point.

[0075] The identification module 440 is used to determine the current change trend of each branch's M consecutive sampling points output by the comparison module after the differential protection is activated. If the current change trend of a branch's M consecutive sampling points all increase, the branch current is determined to be increasing. If the current change trend of a branch's M consecutive sampling points all decrease, the branch current is determined to be decreasing. If no branch current shows an increasing trend, the branch with decreasing current is determined to be a CT disconnection branch, and the differential protection is blocked. If a branch current shows an increasing trend, it is determined that no CT disconnection has occurred, and the differential protection is not blocked.

[0076] The device performs functions similar to those described above; other functions are described in the preceding descriptions and will not be repeated here.

[0077] Figure 5A block diagram of an electronic device according to an exemplary embodiment is shown.

[0078] The following reference Figure 5 To describe an electronic device 500 according to this embodiment of the present application. Figure 5 The electronic device 500 shown is merely an example and should not impose any limitations on the functionality and scope of use of the embodiments of this application.

[0079] like Figure 5 As shown, the electronic device 500 is presented in the form of a general-purpose computing device. The components of the electronic device 500 may include, but are not limited to: at least one processing unit 510, at least one storage unit 520, a bus 530 connecting different system components (including storage unit 520 and processing unit 510), a display unit 540, etc.

[0080] The storage unit stores program code, which can be executed by the processing unit 510, causing the processing unit 510 to perform the methods described in this specification according to various exemplary embodiments of this application.

[0081] Storage unit 520 may include a readable medium in the form of a volatile storage unit, such as random access memory (RAM) 5201 and / or cache memory 5202, and may further include a read-only memory (ROM) 5203.

[0082] Storage unit 520 may also include a program / utility 5204 having a set (at least one) program module 5205, such program module 5205 including but not limited to: operating system, one or more application programs, other program modules and program data, each or some combination of these examples may include an implementation of a network environment.

[0083] Bus 530 can represent one or more of several types of bus structures, including a memory cell bus or memory cell controller, a peripheral bus, a graphics acceleration port, a processing unit, or a local bus using any of the various bus structures.

[0084] Electronic device 500 can also communicate with one or more external devices 600 (e.g., keyboard, pointing device, Bluetooth device, etc.), and with one or more devices that enable a user to interact with electronic device 500, and / or with any device that enables electronic device 500 to communicate with one or more other computing devices (e.g., router, modem, etc.). This communication can be performed via input / output (I / O) interface 550. Furthermore, electronic device 500 can also communicate with one or more networks (e.g., local area network (LAN), wide area network (WAN), and / or public networks, such as the Internet) via network adapter 560. Network adapter 560 can communicate with other modules of electronic device 500 via bus 530. It should be understood that, although not shown in the figures, other hardware and / or software modules can be used in conjunction with electronic device 500, including but not limited to: microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, tape drives, and data backup storage systems.

[0085] Through the above description of the embodiments, those skilled in the art will readily understand that the exemplary embodiments described herein can be implemented by software or by combining software with necessary hardware. The technical solutions according to the embodiments of this application can be embodied in the form of a software product, which can be stored in a non-volatile storage medium (such as a CD-ROM, USB flash drive, external hard drive, etc.) or on a network, including several instructions to cause a computing device (such as a personal computer, server, or network device, etc.) to execute the methods described above according to the embodiments of this application.

[0086] Software products may employ any combination of one or more readable media. A readable medium may be a readable signal medium or a readable storage medium. A readable storage medium may be, for example,, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples of readable storage media (a non-exhaustive list) include: electrical connections with one or more wires, portable disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof.

[0087] Computer-readable storage media may include data signals propagated in baseband or as part of a carrier wave, carrying readable program code. Such propagated data signals may take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. A readable storage medium may also be any readable medium other than a readable storage medium that can transmit, propagate, or transfer a program for use by or in connection with an instruction execution system, apparatus, or device. The program code contained on the readable storage medium may be transmitted using any suitable medium, including but not limited to wireless, wired, optical fiber, RF, etc., or any suitable combination thereof.

[0088] Program code for performing the operations of this application can be written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Java and C++, and conventional procedural programming languages ​​such as C or similar languages. The program code can execute entirely on the user's computing device, partially on the user's computing device, as a standalone software package, partially on the user's computing device and partially on a remote computing device, or entirely on a remote computing device or server. In cases involving remote computing devices, the remote computing device can be connected to the user's computing device via any type of network, including a local area network (LAN) or a wide area network (WAN), or it can be connected to an external computing device (e.g., via the Internet using an Internet service provider).

[0089] Those skilled in the art will understand that the above modules can be distributed in the device as described in the embodiments, or they can be modified accordingly and placed in one or more devices that are unique to this embodiment. The modules in the above embodiments can be combined into one module, or they can be further divided into multiple sub-modules.

[0090] Exemplary embodiments of this application have been specifically shown and described above. It should be understood that this application is not limited to the detailed structures, arrangements, or implementation methods described herein; rather, this application is intended to cover various modifications and equivalent arrangements contained within the spirit and scope of the appended claims.

Claims

1. A rapid CT line breakage identification method based on current trend characteristics, characterized in that, The method includes the following steps: Step 1: Collect the current of each branch used by the differential protection and calculate the current amplitude at each sampling point of each branch. ,in, n For the first n One sampling point, ph The current phases are defined, including three phases: A, B, and C; L is the Lth branch. Step 2: Based on the current amplitude at the sampling point Calculate the corresponding current follower value The current following value The specific calculation methods include: Step 2.1: Calculate the difference between the current amplitude at sampling point n and the current following value at the previous sampling point n-1 to obtain the first difference value. ;in, The current following value corresponding to sampling point n-1, the initial current following value. Set to 0; Step 2.2: Calculate the first difference. The accumulated value of the amplitude difference is calculated as follows: ,in This is the accumulated value of the amplitude difference corresponding to sampling point n. This is the accumulated amplitude difference value corresponding to the previous sampling point n-1. The initial value of the accumulated amplitude difference value at sampling point 0 is set to 0. Step 2.3: If A positive value indicates that the current is gradually increasing, and the sampling point will be adjusted accordingly. The sum of amplitude differences divided by the first coefficient k 1 In addition to the previous sampling point n The current follower value of -1 is the sampling point. n The current follower value is calculated as follows: ; like A negative value indicates that the current is gradually decreasing, and the sampling point should be adjusted accordingly. n The sum of amplitude differences divided by the second coefficient k 2 In addition to the previous sampling point n The current follower value of -1 is the sampling point. n The current follower value is calculated as follows: ; Step 3: Compare the current amplitude at the sampling point with its corresponding current tracking value to determine the current change trend at the sampling point; Step 4: After the differential protection is activated, determine the continuity of each branch. M The current change trend at each sampling point, if a certain branch is continuous M If the current change trend at each sampling point is increasing, then the current in that branch is determined to be increasing. If a branch is continuously increasing... M If the current change trend at each sampling point is decreasing, the branch current is determined to be decreasing; if no branch current shows an increasing trend, the branch with decreasing current is judged to be a CT disconnection branch, and differential protection is blocked; if there is a branch current showing an increasing trend, it is judged that no CT disconnection has occurred, and differential protection is not blocked.

2. The rapid CT line breakage identification method based on current trend characteristics according to claim 1, characterized in that, The method for calculating the current amplitude in step 1 is as follows: in, ph The current phases are defined, including three phases: A, B, and C; L is the Lth branch. For branch L n Sampling point time ph Phase current amplitude; For branch L n Sampling points ph The current sample value of the phase; N is the number of sampling points per cycle.

3. The rapid CT line breakage identification method based on current trend characteristics according to claim 1, characterized in that, Step 2.2 also includes: like and The product of is negative, indicating that n The current trend changed at the sampling point, at which point... Reset to zero, then n The cumulative difference of the sampling points is then: .

4. The rapid CT line breakage identification method based on current trend characteristics according to claim 1, characterized in that, In step 2.3, the first coefficient k 1 Second coefficient k 2 The value range is 2 to 10.

5. The rapid CT line breakage identification method based on current trend characteristics according to claim 1, characterized in that, In step 3, when the amplitude of the sampling point is less than the corresponding current following value, it is determined that the current at the sampling point is trending downwards; when the amplitude of the sampling point is greater than the corresponding current following value, it is determined that the current at the sampling point is trending upwards.

6. The rapid CT line breakage identification method based on current trend characteristics according to claim 5, characterized in that, The method for determining the trend of current change at the sampling point in step 3 is as follows: If If the current at that sampling point is trending downwards, then it is determined that the current is decreasing. If so, it can be determined that the current at that sampling point is trending upwards; in, k 3 , k 4 For a fixed threshold, k 3 , k 4 The value range is 0.04 to 0.

1. I n , I n This is the secondary rated current value.

7. The rapid CT line breakage identification method based on current trend characteristics according to claim 1, characterized in that, In step 4, the continuity is determined. M The current variation trend at each sampling point, among which... M The range of values ​​is M ≥4.

8. A device for rapid CT line breakage identification based on current trend characteristics, characterized in that, include: The sampling module is used to collect the current of each branch used by the differential protection and to calculate the current amplitude at each sampling point of each branch. ,in, n For the first n One sampling point, ph The current phases are defined, including three phases: A, B, and C; L is the Lth branch. The current follower value calculation module is used to calculate the current amplitude based on the sampling point. Calculate the corresponding current follower value The current following value The specific calculation methods include: The first difference is obtained by calculating the difference between the current amplitude at sampling point n and the current following value at the previous sampling point n-1. ;in, The current following value corresponding to sampling point n-1, the initial current following value. Set to 0; The first difference The accumulated value of the amplitude difference is calculated as follows: ,in This is the accumulated value of the amplitude difference corresponding to sampling point n. This is the accumulated amplitude difference value corresponding to the previous sampling point n-1. The initial value of the accumulated amplitude difference value at sampling point 0 is set to 0. like A positive value indicates that the current is gradually increasing, and the sampling point will be adjusted accordingly. n The sum of amplitude differences divided by the first coefficient k 1 In addition to the previous sampling point n The current follower value of -1 is the sampling point. n The current follower value is calculated as follows: ; like A negative value indicates that the current is gradually decreasing, and the sampling point should be adjusted accordingly. n The sum of amplitude differences divided by the second coefficient k 2 In addition to the previous sampling point n The current follower value of -1 is the sampling point. n The current follower value is calculated as follows: ; The comparison module is used to compare the current amplitude of each sampling point with its corresponding current tracking value to determine the current change trend of the sampling point. The identification module is used to determine the continuity of each branch after the differential protection is activated. M The trend of current change at the sampling points output by the comparison module, if a certain branch is continuous M If the current change trend at each sampling point is increasing, then the current in that branch is determined to be increasing. If a branch is continuously increasing... M If the current change trend at each sampling point is decreasing, the branch current is determined to be decreasing; if no branch current shows an increasing trend, the branch with decreasing current is judged to be a CT disconnection branch, and differential protection is blocked; if there is a branch current showing an increasing trend, it is judged that no CT disconnection has occurred, and differential protection is not blocked.

9. An electronic device, characterized in that, include: processor; A memory, and a computer program stored in the memory and executable on the processor, characterized in that the processor, when executing the computer program, implements the method of any one of claims 1-7.

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