Transformer protection starting method and device based on high-sensitivity starting element

Abstract

The invention discloses a transformer protection starting method and device based on a high-sensitivity starting element. The method comprises the following steps: according to the collected current of each side of a transformer, calculating the current sampling value variation of each side of the transformer; determining the starting condition of the starting element on each side according to the current sampling value variation of each side of the transformer and a pre-constructed starting criterion of the starting element on each side; and determining whether the transformer starts protection or not according to the starting condition of the starting element on each side.

Description

Technical Field

[0001] The present invention relates to the technical field of relay protection of power systems, and more specifically, to a transformer protection starting method and device based on a high-sensitivity starting element. Background Art

[0002] In recent years, my country's renewable energy power generation represented by wind power and photovoltaic power has continued to grow rapidly, leading to profound changes in the power supply structure in the power system. The existing AC protection principle is based on the power frequency phase quantity, which requires Fourier transformation to extract the amplitude and phase information of the power frequency component, and requires a data window length of 20ms. On this basis, the fault location and fault type are judged. The starting element is an important part of the line protection. The action performance of the starting element directly affects the action speed of the protection. When the line starting element is activated, the line protection begins to calculate, so the calculation data window of the starting element will affect the action speed of the starting element, and then affect the action time of the line protection. The existing starting element adopts the sudden change starting and zero-sequence current starting algorithms. The former can realize phase starting, but still requires a shorter data window, and the latter does not require a data window, which can quickly identify ground faults, but cannot identify phase-to-phase short circuits. In order to improve the sensitivity and action speed of the starting element, domestic and foreign scholars have proposed a starting element algorithm based on traveling waves and wavelet transforms, but the sampling rate and data processing capabilities are required to be high, which limits its scope of use. Summary of the invention

[0003] In view of the deficiencies in the prior art, the present invention provides a transformer protection starting method and device based on a high-sensitivity starting element.

[0004] According to one aspect of the present invention, a transformer protection starting method based on a high-sensitivity starting element is provided, comprising:

[0005] According to the collected currents on each side of the transformer, the variation of the current sampling values ​​on each side of the transformer is calculated;

[0006] Determine the starting status of the starting elements on each side according to the variation of the current sampling values ​​on each side of the transformer and the pre-constructed starting criteria of the starting elements on each side;

[0007] Determine whether the transformer should start protection based on the starting status of the starting elements on each side.

[0008] Optionally, the calculation formula for the change in the current sampling value is:

[0009]

[0010] In the formula, is the current sampling value of each phase on the high voltage, medium voltage and low voltage sides at the current moment, is the current sampling value before 20ms, N is the number of sampling points corresponding to 20ms, The values ​​are A, B, and C respectively.

[0011] Optionally, the start criteria include:

[0012] High voltage side startup criteria:

[0013] △f H (t)=|f H (t)-f H (tN / 4)|>f H.set

[0014] Among them, f H (t)=[△i Ha (t)-△i Hb (t)] 2 +[△i Hb (t)-△i Hc (t)] 2 +[△i Hc (t)-△i Ha (t)] 2 , f H (tN / 4) is 5ms ago H (t), f H.set is the constant value of the criterion, and f H.set =I H.set +0.5△f Hmax ;f H.set Including fixed part I H.set and floating fixed value △f Hmax , △f Hmax =max(△f H (tN),…,△f H (tN / 2));

[0015] Start-up criteria for medium voltage side:

[0016] △f M (t)=|f M (t)-f M (tN / 4)|>f M.set

[0017] Among them, f M (t)=[△i Ma (t)-△i Mb (t)] 2 +[△i Mb (t)-△i Mc (t)] 2 +[△i Mc (t)-△i Ma (t)]2 , f M (tN / 4) is 5ms ago M (t), f M.set is the constant value of the criterion, and f M.set =I set +0.5△f Mmax ;f M.set Including fixed part I M.set and floating fixed value △f Mmax , △f Mmax =max(△f M (tN),…,△f M (tN / 2));

[0018] Low voltage side startup criteria:

[0019] △f L (t)=|f L (t)-f L (tN / 4)|>f L.set

[0020] Among them, f L (t)=[△i La (t)-△i Lb (t)] 2 +[△i Lb (t)-△i Lc (t)] 2 +[△i Lc (t)-△i La (t)] 2 , f L (tN / 4) is 5ms ago L (t), f 1.set is the constant value of the criterion, and f L.set =I L.set +0.5△f Lmax ;f L.set Including fixed part I L.set and floating fixed value △f Lmax , △f Lmax =max(△f L (tN),…,△f L (tN / 2)).

[0021] Optionally, determining whether to start protection of the transformer according to the starting conditions of the starting elements at each side includes:

[0022] When the starting condition of any starting element on each side is actuated, the transformer protection is started.

[0023] According to another aspect of the present invention, there is provided a transformer protection starting device based on a high-sensitivity starting element, comprising:

[0024] A calculation module, used to calculate the change of the current sampling value on each side of the transformer according to the collected current on each side of the transformer;

[0025] The first determination module is used to determine the start-up status of the start-up elements on each side according to the change amount of the current sampling value on each side of the transformer and the pre-constructed start-up criterion of the start-up elements on each side;

[0026] The second determination module is used to determine whether to start the protection of the transformer according to the starting conditions of the starting elements on each side.

[0027] According to another aspect of the present invention, a computer-readable storage medium is provided, wherein the storage medium stores a computer program, and the computer program is used to execute the method described in any one of the above aspects of the present invention.

[0028] According to another aspect of the present invention, an electronic device is provided, comprising: a processor; a memory for storing instructions executable by the processor; the processor is configured to read the executable instructions from the memory and execute the instructions to implement the method described in any one of the above aspects of the present invention.

[0029] Therefore, the present invention proposes a high-sensitivity starting element for transformer protection using current sampling values. By collecting the current sampling values ​​on each side of the transformer and processing the data, a high-sensitivity starting criterion for identifying transformer faults is established. Under normal circumstances, the three-phase currents are symmetrical and the starting element does not operate; when the transformer fails, the symmetry of the three-phase current is destroyed and the starting element operates quickly, which is suitable for transformer protection of various voltage levels. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] A more complete understanding of exemplary embodiments of the present invention may be obtained by referring to the following drawings:

[0031] Figure 1 It is a flow chart of a transformer protection starting method based on a high-sensitivity starting element provided by an exemplary embodiment of the present invention;

[0032] Figure 2 It is a schematic diagram of an action logic based on a high-sensitivity starting element provided by an exemplary embodiment of the present invention;

[0033] Figure 3 It is a schematic diagram of high voltage side current sampling values ​​before and after a phase A grounding fault in a medium voltage side area provided by an exemplary embodiment of the present invention;

[0034] Figure 4It is a schematic diagram of current sampling values ​​on the medium voltage side before and after a phase A grounding fault in a medium voltage side area provided by an exemplary embodiment of the present invention;

[0035] Figure 5 It is a schematic diagram of low-voltage side current sampling values ​​before and after a phase A grounding fault in a medium-voltage side area provided by an exemplary embodiment of the present invention;

[0036] Figure 6 is a schematic diagram of the high-voltage side startup situation before and after a fault provided by an exemplary embodiment of the present invention;

[0037] Figure 7 is a schematic diagram of the startup of the medium voltage side before and after a fault provided by an exemplary embodiment of the present invention;

[0038] Figure 8 is a schematic diagram of the low-voltage side startup situation before and after a fault provided by an exemplary embodiment of the present invention;

[0039] Fig. 9 It is a structural schematic diagram of a transformer protection starting device based on a high-sensitivity starting element provided by an exemplary embodiment of the present invention;

[0040] Fig.10 This is a structure of an electronic device provided by an exemplary embodiment of the present invention. DETAILED DESCRIPTION

[0041] Below, the exemplary embodiments according to the present invention will be described in detail with reference to the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments of the present invention, and it should be understood that the present invention is not limited to the exemplary embodiments described here.

[0042] It should be noted that the relative arrangement of components and steps, the numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present invention unless specifically stated otherwise.

[0043] Those skilled in the art can understand that the terms "first" and "second" in the embodiments of the present invention are only used to distinguish different steps, devices or modules, etc., and neither represent any specific technical meaning nor indicate the necessary logical order between them.

[0044] It should also be understood that, in the embodiments of the present invention, “plurality” may refer to two or more than two, and “at least one” may refer to one, two or more than two.

[0045] It should also be understood that any component, data or structure mentioned in the embodiments of the present invention can generally be understood as one or more, unless explicitly limited or otherwise indicated in the context.

[0046] In addition, the term "and / or" in the present invention is only a description of the association relationship of the associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in the present invention generally indicates that the associated objects before and after are in an "or" relationship.

[0047] It should also be understood that the description of the various embodiments of the present invention focuses on the differences between the various embodiments, and the same or similar aspects thereof can be referenced to each other, and for the sake of brevity, they will not be described one by one.

[0048] At the same time, it should be understood that for the convenience of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship.

[0049] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses.

[0050] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered part of the specification.

[0051] It should be noted that like reference numerals and letters refer to similar items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0052] Embodiments of the present invention can be applied to electronic devices such as terminal devices, computer systems, servers, etc., which can operate with many other general or special computing system environments or configurations. Examples of well-known terminal devices, computing systems, environments and / or configurations suitable for use with electronic devices such as terminal devices, computer systems, servers, etc. include, but are not limited to: personal computer systems, server computer systems, thin clients, thick clients, handheld or laptop devices, microprocessor-based systems, set-top boxes, programmable consumer electronics, network personal computers, small computer systems, large computer systems, and distributed cloud computing technology environments including any of the above systems, etc.

[0053] Electronic devices such as terminal devices, computer systems, servers, etc. can be described in the general context of computer system executable instructions (such as program modules) executed by computer systems. Generally, program modules can include routines, programs, object programs, components, logic, data structures, etc., which perform specific tasks or implement specific abstract data types. Computer systems / servers can be implemented in a distributed cloud computing environment, where tasks are performed by remote processing devices linked through a communication network. In a distributed cloud computing environment, program modules can be located on local or remote computing system storage media including storage devices.

[0054] Exemplary Methods

[0055] Figure 1 1 is a flow chart of a transformer protection startup method based on a high-sensitivity startup element provided by an exemplary embodiment of the present invention. This embodiment can be applied to electronic devices, such as Figure 1 As shown, the transformer protection starting method 100 based on the high-sensitivity starting element includes the following steps:

[0056] Step 101, calculating the change of the current sampling value on each side of the transformer according to the collected current on each side of the transformer;

[0057] Step 102, determining the start-up status of the start-up elements on each side according to the change in the current sampling value on each side of the transformer and the pre-constructed start-up criteria of the start-up elements on each side;

[0058] Step 103, determining whether the transformer should be protected according to the start-up status of the start-up elements on each side.

[0059] Specifically, the present invention proposes a transformer protection high-sensitivity starting element using current sampling values, and uses the three-phase currents on each side of the transformer at the same time to construct the starting element judgment criteria. Under normal circumstances, the three-phase currents are symmetrical, and the symmetry of the three-phase currents is destroyed when a fault occurs, thereby realizing rapid detection of transformer faults. The method includes the following steps.

[0060] (1) Collect the current on each side of the transformer and calculate the change in the current sampling value of each side.

[0061] The calculation formula for the change of current sampling value △i(t) on each side is:

[0062]

[0063] Where: is the current sampling value of each phase on the high, medium and low voltage sides at the current moment, is the current sampling value before 20ms, N is the number of sampling points corresponding to 20ms, The values ​​are A, B, and C respectively.

[0064] (2) Construct the starting elements on each side. The starting criterion for the high-voltage side is:

[0065] △f H (t)=|f H (t)-f H (tN / 4)|>f H.set (4)

[0066] Among them, f H (t)=[△i Ha (t)-△i Hb (t)] 2 +[△i Hb (t)-△i Hc (t)] 2 +[△i Hc (t)-△i Ha (t)] 2 , f H (tN / 4) is 5ms ago H (t), f H.set is the constant value of the criterion, and f H.set =I H.set +0.5△f Hmax .f H.set Including fixed part I H.set and floating fixed value △f Hmax △f Hmax =max(△f H (tN),…,△f H (tN / 2)).

[0067] The starting criteria for the medium voltage side are:

[0068] △f M (t)=|f M (t)-f M (tN / 4)|>f M.set (5)

[0069] Among them, f M (t)=[△i Ma (t)-△i Mb (t)] 2 +[△i Mb (t)-△i Mc (t)] 2 +[△i Mc (t)-△i Ma (t)] 2 , f M (tN / 4) is 5ms ago M (t), f M.setis the constant value of the criterion, and f M.set =I set +0.5△f Mmax .f M.set Including fixed part I M.set and floating fixed value △f Mmax △f Mmax =max(△f M (tN),…,△f M (tN / 2)).

[0070] The low-voltage side startup criterion is

[0071] △f L (t)=|f L (t)-f L (tN / 4)|>f L.set (6)

[0072] Among them, f L (t)=[△i La (t)-△i Lb (t)] 2 +[△i Lb (t)-△i Lc (t)] 2 +[△i Lc (t)-△i La (t)] 2 , f L (tN / 4) is 5ms ago L (t), f 1.set is the constant value of the criterion, and f L.set =I L.set +0.5△f Lmax .f L.set Including fixed part I L.set and floating fixed value △f Lmax △f Lmax =max(△f L (tN),…,△f L (tN / 2)).

[0073] (3)Reference Figure 2 As shown, the action logic of the starting element is: the starting element on any side of the high, medium or low voltage side is activated, and the transformer protection is started.

[0074] aNormal operation:

[0075] The three-phase current on each side is symmetrical, f H (t), f M (t), f L (t) are all fixed values, △f H (t), △f M(t), △f L (t) is close to 0 and less than the set value, so the starting element does not work.

[0076] b Transformer failure:

[0077] The symmetry of the three-phase current on each side is destroyed, f H (t), f M (t), f L (t) is a fixed value superimposed with a 100Hz component, △f H (t), △f M (t), △f L (t) changes significantly and is greater than the set value, causing the starting element to operate.

[0078] In one embodiment of the present invention, for a 220kv / 110kv / 35KV transformer,

[0079] (1) Collect the current on each side of the transformer and calculate the change in the current sampling value of each side, such as Figure 3 , Figure 4 , Figure 5 As shown;

[0080] (2) Calculate f H (t), f M (t), f L (t), such as Figure 3 , Figure 4 , Figure 5 As shown;

[0081] (3) Calculation of △f H (t), △f M (t), △f L (t), such as Figure 6 , Figure 7 , Figure 8 As shown;

[0082] (4) During normal operation, the starting elements on each side do not operate, but in the event of a fault, they operate.

[0083] Therefore, the present invention proposes a high-sensitivity starting element for transformer protection using current sampling values. By collecting the current sampling values ​​on each side of the transformer and processing the data, a high-sensitivity starting criterion for identifying transformer faults is established. Under normal circumstances, the three-phase currents are symmetrical and the starting element does not operate; when the transformer fails, the symmetry of the three-phase current is destroyed and the starting element operates quickly, which is suitable for transformer protection of various voltage levels.

[0084] Exemplary Devices

[0085] Fig. 9FIG. 1 is a schematic diagram of a transformer protection starting device based on a high-sensitivity starting element provided by an exemplary embodiment of the present invention. Fig. 9 As shown, the device 900 includes:

[0086] The calculation module 910 is used to calculate the change of the current sampling value of each side of the transformer according to the collected current of each side of the transformer;

[0087] The first determination module 920 is used to determine the start-up status of the start-up elements on each side according to the change of the current sampling value on each side of the transformer and the pre-constructed start-up criterion of the start-up elements on each side;

[0088] The second determination module 930 is used to determine whether to start the protection of the transformer according to the start-up status of the start-up elements at each side.

[0089] Optionally, the calculation formula for the change in the current sampling value is:

[0090]

[0091] In the formula, is the current sampling value of each phase on the high voltage, medium voltage and low voltage sides at the current moment, is the current sampling value before 20ms, N is the number of sampling points corresponding to 20ms, The values ​​are A, B, and C respectively.

[0092] Optionally, the start criteria include:

[0093] High voltage side startup criteria:

[0094] △f H (t)=|f H (t)-f H (tN / 4)|>f H.set

[0095] Among them, f H (t)=[△i Ha (t)-△i Hb (t)] 2 +[△i Hb (t)-△i Hc (t)] 2 +[△i Hc (t)-△i Ha (t)] 2 , f H (tN / 4) is 5ms ago H (t), f H.set is the constant value of the criterion, and f H.set =I H.set +0.5△f Hmax ;fH.set Including fixed part I H.set and floating fixed value △f Hmax , △f Hmax =max(△f H (tN),…,△f H (tN / 2));

[0096] Start-up criteria for medium voltage side:

[0097] △f M (t)=|f M (t)-f M (tN / 4)|>f M.set

[0098] Among them, f M (t)=[△i Ma (t)-△i Mb (t)] 2 +[△i Mb (t)-△i Mc (t)] 2 +[△i Mc (t)-△i Ma (t)] 2 , f M (tN / 4) is 5ms ago M (t), f M.set is the constant value of the criterion, and f M.set =I set +0.5△f Mmax ;f M.set Including fixed part I M.set and floating fixed value △f Mmax , △f Mmax =max(△f M (tN),…,△f M (tN / 2));

[0099] Low voltage side startup criteria:

[0100] △f L (t)=|f L (t)-f L (tN / 4)|>f L.set

[0101] Among them, f L (t)=[△i La (t)-△i Lb (t)] 2 +[△i Lb (t)-△i Lc (t)] 2 +[△i Lc(t)-△i La (t)] 2 , f L (tN / 4) is 5ms ago L (t), f 1.set is the constant value of the criterion, and f L.set =I L.set +0.5△f Lmax ;f L.set Including fixed part I L.set and floating fixed value △f Lmax , △f Lmax =max(△f L (tN),…,△f L (tN / 2)).

[0102] Optionally, the second determining module 930 includes:

[0103] The starter module is used to start the transformer protection when the start condition of any starter element on each side is action.

[0104] Exemplary Electronic Devices

[0105] Fig.10 This is a structure of an electronic device provided by an exemplary embodiment of the present invention. Fig.10 As shown, the electronic device 100 includes one or more processors 101 and a memory 102 .

[0106] The processor 101 may be a central processing unit (CPU) or other forms of processing units having data processing capabilities and / or instruction execution capabilities, and may control other components in the electronic device to perform desired functions.

[0107] The memory 102 may include one or more computer program products, and the computer program product may include various forms of computer-readable storage media, such as volatile memory and / or non-volatile memory. The volatile memory may include, for example, random access memory (RAM) and / or cache memory (cache), etc. The non-volatile memory may include, for example, read-only memory (ROM), hard disk, flash memory, etc. One or more computer program instructions may be stored on the computer-readable storage medium, and the processor 101 may run the program instructions to implement the methods of the software programs of the various embodiments of the present invention described above and / or other desired functions. In one example, the electronic device may also include: an input device 103 and an output device 104, which are interconnected via a bus system and / or other forms of connection mechanisms (not shown).

[0108] In addition, the input device 103 may also include, for example, a keyboard, a mouse, and the like.

[0109] The output device 104 can output various information to the outside, and can include, for example, a display, a speaker, a printer, a communication network and a remote output device connected thereto.

[0110] Of course, to simplify, Fig.10 Only some of the components related to the present invention in the electronic device are shown, and components such as a bus, an input / output interface, etc. are omitted. In addition, the electronic device may further include any other appropriate components according to specific application conditions.

[0111] Exemplary computer program products and computer-readable storage media

[0112] In addition to the above-mentioned methods and devices, an embodiment of the present invention may also be a computer program product, which includes computer program instructions, which, when executed by a processor, enable the processor to execute the steps of the method according to various embodiments of the present invention described in the above-mentioned "Exemplary Method" section of this specification.

[0113] The computer program product may be written in any combination of one or more programming languages ​​to write program code for performing the operations of the embodiments of the present invention, including object-oriented programming languages ​​such as Java, C++, etc., and conventional procedural programming languages ​​such as "C" or similar programming languages. The program code may be executed entirely on the user computing device, partially on the user device, as a separate software package, partially on the user computing device and partially on a remote computing device, or entirely on a remote computing device or server.

[0114] In addition, an embodiment of the present invention may also be a computer-readable storage medium having computer program instructions stored thereon, which, when executed by a processor, enable the processor to execute the steps of the method according to various embodiments of the present invention described in the above “Exemplary Method” section of this specification.

[0115] The computer readable storage medium can adopt any combination of one or more readable media. The readable medium can be a readable signal medium or a readable storage medium. The readable storage medium can include, for example, but is not limited to, a system, system or device of electricity, magnetism, light, electromagnetic, infrared, or semiconductor, or any combination of the above. More specific examples (non-exhaustive list) of readable storage media include: an electrical connection with one or more wires, a portable disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above.

[0116] The basic principle of the present invention is described above in conjunction with specific embodiments. However, it should be pointed out that the advantages, strengths, effects, etc. mentioned in the present invention are only examples and not limitations, and it cannot be considered that these advantages, strengths, effects, etc. must be possessed by each embodiment of the present invention. In addition, the specific details disclosed above are only for the purpose of illustration and facilitation of understanding, rather than limitation, and the above details do not limit the present invention to being implemented by adopting the above specific details.

[0117] Each embodiment in this specification is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the system embodiment, since it basically corresponds to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

[0118] The block diagrams of the devices, systems, equipment, and systems involved in the present invention are only illustrative examples and are not intended to require or imply that they must be connected, arranged, and configured in the manner shown in the block diagram. As will be appreciated by those skilled in the art, these devices, systems, equipment, and systems can be connected, arranged, and configured in any manner. Words such as "including", "comprising", "having", etc. are open words, referring to "including but not limited to", and can be used interchangeably with them. The words "or" and "and" used here refer to the words "and / or" and can be used interchangeably with them, unless the context clearly indicates otherwise. The word "such as" used here refers to the phrase "such as but not limited to", and can be used interchangeably with it.

[0119] The method and system of the present invention may be implemented in many ways. For example, the method and system of the present invention may be implemented by software, hardware, firmware or any combination of software, hardware, firmware. The above order of steps for the method is only for illustration, and the steps of the method of the present invention are not limited to the order specifically described above, unless otherwise specifically stated. In addition, in some embodiments, the present invention may also be implemented as a program recorded in a recording medium, which includes machine-readable instructions for implementing the method according to the present invention. Thus, the present invention also covers a recording medium storing a program for executing the method according to the present invention.

[0120] It should also be noted that in the system, device and method of the present invention, each component or each step can be decomposed and / or recombined. These decompositions and / or recombinations should be regarded as equivalent schemes of the present invention. The above description of the disclosed aspects is provided to enable any technician in the field to make or use the present invention. Various modifications to these aspects are very obvious to those skilled in the art, and the general principles defined here can be applied to other aspects without departing from the scope of the present invention. Therefore, the present invention is not intended to be limited to the aspects shown here, but in accordance with the widest range consistent with the principles and novel features disclosed here.

[0121] The above description has been given for the purpose of illustration and description. In addition, this description is not intended to limit the embodiments of the present invention to the forms disclosed herein. Although a number of example aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, changes, additions and sub-combinations thereof.

Claims

1. A transformer protection starting method based on a high-sensitivity starting element, characterized in that: include: Calculate the change of the current sampling value on each side of the transformer according to the collected current on each side of the transformer; Determining the starting status of the starting element on each side according to the variation of the current sampling value on each side of the transformer and the pre-constructed starting criteria of the starting element on each side; Whether the transformer starts protection is determined according to the starting conditions of the starting elements on each side.

2. The method according to claim 1, characterized in that The calculation formula of the current sampling value change is: In the formula, is the current sampling value of each phase on the high voltage, medium voltage and low voltage sides at the current moment, is the current sampling value before 20ms, N is the number of sampling points corresponding to 20ms, The values ​​are A, B, and C respectively.

3. The method according to claim 1, characterized in that The startup criteria include: High-voltage side startup criteria: △f H (t)=|f H (t)-f H (t-N / 4)|>f H.set Among them, f H (t)=[△i Ha (t)-△i Hb (t)] 2 +[△i Hb (t)-△i Hc (t)] 2 +[△i Hc (t)-△i Ha (t)] 2 , f H (tN / 4) is 5ms ago H (t), f H.set is the constant value of the criterion, and f H.set =I H.set +0.5△f Hmax ;f H.set Including fixed part I H.set and floating fixed value △f Hmax , △f Hmax =max(△f H (tN),…,△f H (tN / 2)); Start-up criteria for medium voltage side: △f M (t)=|f M (t)-f M (t-N / 4)|>f M.set Among them, f M (t)=[△i Ma (t)-△i Mb (t)] 2 +[△i Mb (t)-△i Mc (t)] 2 +[△i Mc (t)-△i Ma (t)] 2 , f M (tN / 4) is 5ms ago M (t), f M.set is the constant value of the criterion, and f M.set =I set +0.5△f Mmax ;f M.set Including fixed part I M.set and floating fixed value △f Mmax , △f Mmax =max(△f M (tN),…,△f M (tN / 2)); Low voltage side startup criteria: △f L (t)=|f L (t)-f L (t-N / 4)|>f L.set Among them, f L (t)=[△i La (t)-△i Lb (t)] 2 +[△i Lb (t)-△i Lc (t)] 2 +[△i Lc (t)-△i La (t)] 2 , f L (tN / 4) is 5ms ago L (t), f 1.set is the constant value of the criterion, and f L.set =I L.set +0.5△f Lmax ;f L.set Including fixed part I L.set and floating fixed value △f Lmax , △f Lmax =max(△f L (tN),…,△f L (tN / 2)).

4. The method according to claim 1, characterized in that: Determining whether to start protection of the transformer according to the starting conditions of the starting elements at each side includes: When the starting condition of any one of the starting elements on each side is in action, the transformer protection is started.

5. A transformer protection starting device based on a high-sensitivity starting element, characterized in that: include: A calculation module, used to calculate the change of the current sampling value on each side of the transformer according to the collected current on each side of the transformer; A first determination module, configured to determine the start-up status of the start-up element on each side according to the change in the current sampling value on each side of the transformer and the pre-constructed start-up criterion of the start-up element on each side; The second determination module is used to determine whether to start protection of the transformer according to the starting conditions of the starting elements on each side.

6. The device according to claim 5, characterized in that The calculation formula of the current sampling value change is: In the formula, is the current sampling value of each phase on the high voltage, medium voltage and low voltage sides at the current moment, is the current sampling value before 20ms, N is the number of sampling points corresponding to 20ms, The values ​​are A, B, and C respectively.

7. The device according to claim 5, characterized in that The startup criteria include: High-voltage side startup criteria: △f H (t)=|f H (t)-f H (t-N / 4)|>f H.set Among them, f H (t)=[△i Ha (t)-△i Hb (t)] 2 +[△i Hb (t)-△i Hc (t)] 2 +[△i Hc (t)-△i Ha (t)] 2 , f H (tN / 4) is 5ms ago H (t), f H.set is the constant value of the criterion, and f H.set =I H.set +0.5△f Hmax ;f H.set Including fixed part I H.set and floating fixed value △f Hmax , △f Hmax =max(△f H (tN),…,△f H (tN / 2)); Start-up criteria for medium voltage side: △f M (t)=|f M (t)-f M (t-N / 4)|>f M.set Among them, f M (t)=[△i Ma (t)-△i Mb (t)] 2 +[△i Mb (t)-△i Mc (t)] 2 +[△i Mc (t)-△i Ma (t)] 2 , f M (tN / 4) is 5ms ago M (t), f M.set is the constant value of the criterion, and f M.set =I set +0.5△f Mmax ;f M.set Including fixed part I M.set and floating fixed value △f Mmax , △f Mmax =max(△f M (tN),…,△f M (tN / 2)); Low voltage side startup criteria: △f L (t)=|f L (t)-f L (t-N / 4)|>f L.set Among them, f L (t)=[△i La (t)-△i Lb (t)] 2 +[△i Lb (t)-△i Lc (t)] 2 +[△i Lc (t)-△i La (t)] 2 , f L (tN / 4) is 5ms ago L (t), f 1.set is the constant value of the criterion, and f L.set =I L.set +0.5△f Lmax ;f L.set Including fixed part I L.set and floating fixed value △f Lmax , △f Lmax =max(△f L (tN),…,△f L (tN / 2)).

8. The device according to claim 5, characterized in that The second determination module includes: The starter module is used to start the transformer protection when the start condition of any one of the starter elements on each side is action.

9. A computer-readable storage medium, characterized in that: The storage medium stores a computer program, and the computer program is used to execute the method according to any one of claims 1 to 4.

10. An electronic device, characterized in that: The electronic device comprises: processor; a memory for storing instructions executable by the processor; The processor is used to read the executable instructions from the memory and execute the instructions to implement the method described in any one of claims 1 to 4.

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