Constant value setting method and system for single-ended transient voltage energy type direct current line protection

Abstract

The invention discloses a fixed value setting method and system for single-ended transient voltage energy type direct-current line protection, and the method comprises the steps: obtaining line parameters of each frequency-dependent direct-current line in a direct-current power transmission system, and obtaining a line mode propagation constant; obtaining mode domain parameters of other elements of the direct-current power transmission system, calculating equivalent impedance of a protected line seen from a line fault point, and obtaining a line mode voltage division coefficient of voltage division caused by transition resistance and a mode domain network by using the equivalent impedance; line mode fault voltage frequency response analysis is realized; obtaining an extraction frequency band of the set transient quantity protection, determining a weakest fault transfer function when a weakest fault occurs in the region, and constructing a voltage step function; and calculating transient energy by using the voltage step function to obtain a setting value of direct current line protection based on single-end voltage transient energy. According to the method, the weakest fault can be accurately positioned, so that the direct-current single-end transient state quantity protection constant value is accurately calculated.

Description

Technical Field

[0001] The present invention relates to the fields of relay protection of direct current transmission systems and new energy grid-connected systems, and in particular to a fixed value setting method and system for single-ended direct current line protection. Background Art

[0002] For long-distance power transmission, high-voltage direct current (HVDC) systems offer advantages such as low losses, minimal footprint, and low cost. However, the overcurrent capacity of power electronic components in HVDC grids (such as MMC-HVDC) is limited. Furthermore, with the advancement of DC transmission technology, the application scenarios of DC grids are becoming increasingly complex. Examples include large-scale, long-distance onshore power transmission, multi-terminal interconnection of asynchronous power grids, island networking, and offshore wind power transmission. This places higher demands on DC line protection in terms of speed, adaptability in various scenarios, and practicality in real-world engineering applications.

[0003] Frequency domain-based transient quantity protection in single-ended quantity protection is a single-ended transient quantity protection technology in DC single-ended quantity protection, that is, it corresponds to DC single-ended transient quantity protection. However, most of the current fixed values ​​of single-ended transient quantity protection criteria require a large number of simulations to obtain, and lack a theoretical basis. When the protection needs to be applied to multiple projects, or when the system operation conditions change, the construction, adjustment and testing of the simulation will consume a lot of time. In addition, some existing fixed value setting methods are only for a specific scenario, and the analysis and location of the weakest fault in the area are not clear enough. Therefore, there is an urgent need for a method that can use the weakest fault in the area to accurately calculate the fixed value of DC single-ended transient quantity protection. Summary of the Invention

[0004] The present invention proposes a method and system for setting the fixed value of single-ended transient voltage energy-type DC line protection. By acquiring and calculating line parameters, the line mode fault voltage frequency response analysis is performed to determine the weakest fault in the area, and the setting value of the DC line protection based on the single-ended voltage transient energy is calculated.

[0005] In a first aspect, the present invention provides a method for setting a fixed value of a single-ended transient voltage energy-type DC line protection, the method comprising:

[0006] Obtaining line parameters of each frequency-dependent DC line in the DC transmission system, obtaining ground mode wave impedance and line mode wave impedance based on the line parameters, and obtaining a line mode propagation constant based on the ground mode wave impedance and the line mode wave impedance;

[0007] Implement line mode fault voltage frequency response analysis:

[0008] i. Obtaining the mode domain parameters of other components in the DC transmission system, and calculating the equivalent impedance of the protected DC line at different fault locations as viewed from the line fault point according to the mode domain parameters of the line;

[0009] ii. Using the equivalent impedance to obtain the line mode voltage divider coefficient of the voltage divider caused by the transition resistor and the mode domain network;

[0010] iii. Based on the obtained line mode propagation constant and the line mode voltage divider coefficient, calculate the line mode fault voltage transfer function with the fault voltage at the fault point as the excitation and the fault voltage at the protection installation as the response;

[0011] Obtaining an extracted frequency band for setting transient protection, determining a weakest fault voltage transfer function within the frequency band, and constructing a voltage step function;

[0012] The voltage step function is used to calculate transient energy, and a setting value of DC line protection based on single-ended voltage transient energy is obtained.

[0013] In some embodiments, obtaining a ground mode wave impedance and a line mode wave impedance according to the line parameters, and obtaining a line mode propagation constant according to the ground mode wave impedance and the line mode wave impedance further includes:

[0014] Calculate the ground mode wave impedance of the frequency-dependent DC line based on the line parameters , line mode wave impedance and line mode propagation constant ;

[0015] The ground mode wave impedance and the line mode wave impedance The calculation formula is:

[0016] ;

[0017] Where, 、 represents the self-impedance and mutual impedance of the line, 、 Indicates the self-admittance and mutual-admittance of the line;

[0018] And obtain the line mode propagation constant The calculation formula is:

[0019] ;

[0020] In some embodiments, calculating the equivalent impedance of the protected frequency-dependent DC line as viewed from the line fault point when faults occur at different locations based on the mode domain parameters of the line and other components further includes:

[0021] Obtain the analog domain parameters of other components in the DC transmission system, including at least the DC voltage during normal operation , converter station equivalent impedance , current limiting reactance Etc., and calculate the equivalent impedance of the protected frequency-dependent DC line at different fault locations as seen from the line fault point ; Equivalent impedance There are three situations: line head end fault, line middle fault and line end fault;

[0022] Ground mode equivalent impedance in three cases and line mode equivalent impedance The calculation formula is:

[0023] ;

[0024] Where, and They represent the system ground mode equivalent impedance on the back side of the line head end and the system ground mode equivalent impedance on the back side of the line end, and They represent the ground mode wave impedance and line mode wave impedance of the protected line respectively, || is the parallel symbol, and They represent the system line mode equivalent impedance at the back side of the line head end and the system line mode equivalent impedance at the back side of the line end respectively;

[0025] Then, the line mode voltage division coefficient is obtained The calculation formula is as follows:

[0026] ;

[0027] Where, is the transition resistor.

[0028] In some embodiments, obtaining a line-mode fault voltage transfer function based on the obtained line-mode propagation constant and the line-mode voltage division coefficient, which takes the fault voltage at the fault point as an excitation and the fault voltage at the protection installation as a response, further includes:

[0029] Get the line mode reflection coefficient at the protection installation The calculation formula is:

[0030] ;

[0031] According to the parameters obtained in the above steps, calculate the line mode fault voltage transfer function with the fault voltage at the fault point as the excitation and the fault voltage at the protection installation as the response The calculation formula is:

[0032] ;

[0033] In some embodiments, obtaining an extraction frequency band for setting transient variable protection, determining the weakest fault voltage transfer function within the frequency band to construct a voltage step function further includes:

[0034] Using transient quantity to protect the lower limit of the extracted frequency band The weakest fault transfer function amplitude at frequency Multiply by the rated voltage Construct a voltage step function.

[0035] The transient energy is calculated by using the voltage step function to obtain the setting value of the DC line protection based on the single-ended voltage transient energy. The method further includes: calculating the transient energy of the voltage step function by using the single-ended voltage transient energy algorithm to obtain the transient energy value at the weakest fault. , the calculation formula for the setting value of DC line protection based on single-ended voltage transient energy is: , is the reliability coefficient.

[0036] In a second aspect, the present invention provides a fixed value setting system for single-ended transient voltage energy type DC line protection, which implements a fixed value setting method for single-ended transient voltage energy type DC line protection. The system comprises a line parameter calculation module, a line mode fault voltage frequency response analysis module, a weakest fault determination module within a zone, and a fixed value setting calculation module; wherein:

[0037] The line parameter calculation module obtains line parameters of each frequency-dependent DC line in the DC transmission system, obtains ground mode wave impedance and line mode wave impedance based on the line parameters, and obtains line mode propagation constant based on the ground mode wave impedance and the line mode wave impedance;

[0038] The line mode fault voltage frequency response analysis module implements line mode fault voltage frequency response analysis:

[0039] i. Obtaining the mode domain parameters of other components in the DC transmission system, and calculating the equivalent impedance of the protected DC line at different fault locations as viewed from the line fault point according to the mode domain parameters of the line;

[0040] ii. Using the equivalent impedance to obtain the line mode voltage divider coefficient of the voltage divider caused by the transition resistor and the mode domain network;

[0041] iii. Based on the obtained line mode propagation constant and the line mode voltage divider coefficient, the fault voltage at the fault point is calculated as an excitation, and the line mode fault voltage transmission function of the protection installation at the fault voltage response is calculated;

[0042] The weakest fault determination module in the area obtains the extracted frequency band of the set transient protection, determines the weakest fault voltage transfer function in the frequency band area, and constructs a voltage step function;

[0043] The setting value calculation module calculates transient energy using the voltage step function to obtain a setting value for DC line protection based on single-ended voltage transient energy.

[0044] In some embodiments, the transient energy is calculated using the voltage step function to obtain a setting value of the DC line protection based on the single-ended voltage transient energy. This further includes: calculating the transient energy of the voltage step function using a single-ended voltage transient energy algorithm to obtain the transient energy value at the weakest fault. , the calculation formula for the setting value of DC line protection based on single-ended voltage transient energy is: , is the reliability coefficient.

[0045] In a third aspect, the present invention provides an electronic device comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, a method for setting a constant value of a single-ended transient voltage energy-type DC line protection provided in any of the above-mentioned embodiments is implemented.

[0046] In a fourth aspect, the present invention provides a non-transient computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the method for setting a constant value of a single-ended transient voltage energy-type DC line protection provided in any of the above embodiments is implemented.

[0047] Compared with the prior art, the present invention has the following advantages:

[0048] 1) Based on the obtained line-mode propagation constant and the line-mode voltage division coefficient, a line-mode fault voltage transfer function is obtained, which takes the fault voltage at the fault point as the excitation and the fault voltage at the protection installation location as the response, so that the system can achieve fast, accurate, and stable dynamic response. This is a design that balances system speed and stability, realizes the fixed value setting of the single-ended transient voltage energy-type DC line protection, and thus optimizes the control system performance.

[0049] 2) Find the line-mode fault voltage transfer function with the minimum amplitude when faults occur at different distances in the line. Use this function as the weakest fault transfer function when the weakest fault occurs in the area. Determine the setting value of the DC line protection based on single-ended voltage transient energy based on this weakest fault transfer function, and accurately locate the weakest fault.

[0050] 3) constructing a voltage step function based on the weakest fault transfer function, thereby utilizing the voltage step function to shorten the setting calculation time;

[0051] 4) The voltage step function is used to calculate transient energy to obtain the setting value of DC line protection based on single-ended voltage transient energy, which can accurately calculate the setting value of DC single-ended transient quantity protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 This is an overall flow chart of a fixed value setting method for single-ended transient voltage energy type DC line protection of the present invention;

[0053] Figure 2 This is a technical roadmap of a fixed value setting method for single-ended transient voltage energy type DC line protection of the present invention;

[0054] Figure 3 is a schematic diagram of the topological structure of the test system when a failure occurs in an embodiment of the present invention;

[0055] Figure 4 2. This is a schematic diagram of a module domain fault equivalent network when a line fault occurs in a test system according to an embodiment of the present invention;

[0056] Figure 5 Schematic diagram of physical parameters of a DC overhead line of a test system according to an embodiment of the present invention;

[0057] Figure 6 This is a module diagram of a fixed value setting system for single-ended transient voltage energy type DC line protection of the present invention. DETAILED DESCRIPTION

[0058] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0059] Figure 1 The present invention provides a method for setting a fixed value of a single-ended transient voltage energy-type DC line protection. The specific steps are as follows:

[0060] Step 1: Obtain the line parameters of each frequency-dependent DC line in the DC transmission system, obtain the ground mode wave impedance and line mode wave impedance based on the line parameters, and obtain the line mode propagation constant based on the ground mode wave impedance and the line mode wave impedance.

[0061] Step 1.1: Use electromagnetic field theory and Casson's formula to calculate the frequency-dependent DC line parameters of the DC transmission system, including two frequency-dependent parameters, namely the phase domain impedance matrix and phase domain admittance matrix , and, from the phase domain impedance matrix Extracting the self-impedance of the line and mutual impedance , from the phase domain admittance matrix Extracting the line's self-admittance and mutual admittance ;

[0062] Step 1.2: Calculate the ground mode wave impedance of the frequency-dependent DC line based on the calculated line parameters , line mode wave impedance and line mode propagation constant ;

[0063] Specifically, the ground mode wave impedance and the line mode wave impedance The calculation formula is:

[0064] ; (1)

[0065] Specifically, the line mode propagation constant The calculation formula is:

[0066] ; (2)

[0067] Step 2: Obtaining the mode domain parameters of other components of the DC transmission system, calculating the equivalent impedance of each protected line as seen from the fault point when a fault occurs at different locations based on the line mode domain parameters, and using the equivalent impedance to obtain the line mode voltage division coefficient of the voltage division caused by the transition resistance and the mode domain network. Based on the obtained line mode propagation constant and the line mode voltage division coefficient, obtain a line mode fault voltage propagation function using the fault voltage at the fault point as the excitation and the fault voltage at the protection installation as the response, thereby performing line mode fault voltage frequency response analysis.

[0068] Step 2.1: Obtain the analog domain parameters of other components in the DC transmission system, including at least the DC voltage during normal operation. , converter station equivalent impedance , current limiting reactance Etc., and calculate the equivalent impedance of the protected frequency-dependent DC line at different fault locations as seen from the line fault point . Equivalent impedance There are three situations: line head end fault, line middle fault and line end fault. The ground mode equivalent impedance in the three situations and line mode equivalent impedance The calculation formula is:

[0069] ; (3)

[0070] Where, and They represent the system ground mode equivalent impedance at the back of the line head end and the system ground mode equivalent impedance at the back of the line end, respectively, and || is a parallel symbol; for example Figure 2 For the system topology shown, if protection A is set, then , , m = 0 or 1, indicating the ground mode component or line mode component;

[0071] Step 2.3: Based on the ground mode equivalent impedance from the line fault point obtained in step 3 and line mode equivalent impedance , collectively referred to as equivalent impedance , calculate the transition resistance as Line mode voltage division coefficient C u (1) (f) By Figure 4 The voltage divider coefficient is due to the presence of a transition resistor between the traveling wave source on the DC line at the fault point, which divides part of the fault voltage. For single-pole faults, the ground mode network will also divide part of the voltage. Therefore, according to the different fault poles, C u (1) (f) There are different calculation formulas:

[0072] ; (4)

[0073] Where, is the transition resistance;

[0074] Step 2.4: Calculate the line mode transfer function H of the protected frequency-dependent DC line l (1) (f) and the line mode reflection coefficient k at the transient protection installation location (1) (f); Line mode line transfer function H l (1) The calculation formula for (f) is:

[0075] ; (5)

[0076] Where x is the distance from the fault point to the protection installation location, is the line mode propagation constant;

[0077] Line mode reflection coefficient k at the protection installation location (1) The calculation formula for (f) is:

[0078] ; (6)

[0079] Step 2.5: Based on the parameters obtained in the above steps, calculate the line mode fault voltage transfer function with the fault voltage at the fault point as the excitation and the fault voltage at the protection installation as the response. The calculation formula is:

[0080] ; (7)

[0081] Step 3: Obtain the extracted frequency band of the set transient protection, calculate the amplitude-frequency characteristics of the line-mode fault voltage transfer function within the extracted frequency band, find the line-mode fault voltage transfer function with the smallest amplitude when faults occur at different distances in the line, and use it as the weakest fault transfer function when the weakest fault occurs in the area. Construct a voltage step function based on the weakest fault transfer function.

[0082] Step 3.1: Obtain the lower limit of the extraction frequency band for the set transient protection and extract band caps , calculate the transition resistance required for setting Down, ~ Line mode fault voltage transfer function within the frequency band The amplitude-frequency characteristics of the line mode fault voltage transfer function with the minimum amplitude when faults occur at different distances in the line are found. This is the weakest fault transmission function when the weakest fault occurs in the area. The selection of different fault distances should evenly cover the entire line. 21 fault points, including the line head and line end, can be selected at intervals of 1 / 20 of the line length.

[0083] Step 3.2: The weakest fault transfer function amplitude at frequency Multiply by the rated voltage Construct a voltage step function; where the rated voltage The selection of is related to the fault pole. For single-pole fault, it can be selected as , for a bipolar fault, it is 2 , the voltage step function is expressed as:

[0084] ; (8)

[0085] Where ε(t) is a unit step function. Note that when the fault poles are different, the weakest fault transmission function H u_min (f L ) values ​​are also different;

[0086] Step 4: Calculate the transient energy of the voltage step function using the single-ended voltage transient energy algorithm to obtain the transient energy value at the weakest fault. ,use Divide by the reliability coefficient That is, the setting value of DC line protection based on single-ended voltage transient energy is obtained , the calculation formula is .

[0087] Taking bipolar fault as an example, after substituting specific parameters, the constructed step function is |2U dcN H u_min (f L)|ε(t) = |2* 848.3 * 0.3318|ε(t) = 562.93ε(t). Apply the single-ended voltage transient energy algorithm to extract the transient energy calculation value. = 96264.5, if the reliability coefficient is = 1.5, then the protection setting value can be calculated as E set = 96264.5 / 1.5 = 64176.3.

[0088] like Figure 5 As shown, the fixed value setting system for a single-ended transient voltage energy-based DC line protection system of the present invention includes a line parameter calculation module, a line-mode fault voltage frequency response analysis module, a weakest fault determination module within a zone, and a fixed value setting calculation module. Each module corresponds to the corresponding process of executing the fixed value setting method for a single-ended transient voltage energy-based DC line protection system of the present invention.

[0089] In summary, the present invention can accurately locate the weakest fault, thereby accurately calculating the DC single-ended transient protection setting.

[0090] In addition, based on similar inventive concepts, an embodiment of the present invention also provides an electronic device, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the above method when executing the computer program.

[0091] In addition, based on similar inventive concepts, an embodiment of the present invention further provides a non-transitory computer-readable storage medium having a computer program stored thereon, and the computer program implements the above method when executed by a processor.

[0092] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Thus, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk drives, CD-ROMs, optical storage devices, etc.) containing computer-usable program code. The solutions in the embodiments of the present invention may be implemented using various computer languages, such as the object-oriented programming language Java and the interpreted scripting language JavaScript.

[0093] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowcharts and / or block diagrams, as well as combinations of processes and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowcharts and / or block diagrams. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0094] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0095] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0096] Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0097] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

[0098] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications made without departing from the principles of the present invention should also be considered to fall within the scope of protection of the present invention.

[0099] The preferred embodiments of the present invention are described in detail above in conjunction with the accompanying drawings and technical solutions. This is only a description of the preferred embodiments of the present invention and does not limit the concept and scope of the present invention. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations. The various specific technical features described in the above specific embodiments may be combined, modified or improved in any appropriate manner without contradiction, and shall fall within the scope of protection of the present invention without departing from the concept of the present invention.

Claims

1. A method for setting a fixed value of a single-ended transient voltage energy type DC line protection, characterized in that: The method includes: Obtaining line parameters of each frequency-dependent DC line in the DC transmission system, obtaining ground mode wave impedance and line mode wave impedance based on the line parameters, and obtaining a line mode propagation constant based on the ground mode wave impedance and the line mode wave impedance; Implement line mode fault voltage frequency response analysis: i. Obtaining the mode domain parameters of other components in the DC transmission system, and calculating the equivalent impedance of the protected DC line at different fault locations as viewed from the line fault point according to the mode domain parameters of the line; ii. Using the equivalent impedance to obtain the line mode voltage divider coefficient of the voltage divider caused by the transition resistor and the mode domain network; iii. Based on the obtained line mode propagation constant and the line mode voltage divider coefficient, calculate the line mode fault voltage transfer function with the fault voltage at the fault point as the excitation and the fault voltage at the protection installation as the response; Obtaining an extracted frequency band for setting transient protection, determining a weakest fault voltage transfer function within the frequency band, and constructing a voltage step function; The voltage step function is used to calculate transient energy, and a setting value of DC line protection based on single-ended voltage transient energy is obtained.

2. The method for setting a fixed value of a single-ended transient voltage energy type DC line protection according to claim 1, characterized in that: The method further comprises: obtaining a ground mode wave impedance and a line mode wave impedance according to the line parameters, and obtaining a line mode propagation constant according to the ground mode wave impedance and the line mode wave impedance. Calculate the ground mode wave impedance of the frequency-dependent DC line based on the line parameters , line mode wave impedance and line mode propagation constant ; The ground mode wave impedance and the line mode wave impedance The calculation formula is: ; Where, 、 represents the self-impedance and mutual impedance of the line, 、 Indicates the self-admittance and mutual-admittance of the line; And obtain the line mode propagation constant The calculation formula is: ; 3. The method for setting a fixed value of a single-ended transient voltage energy type DC line protection according to claim 1, characterized in that: Calculating the equivalent impedance of the protected frequency-dependent DC line viewed from the line fault point when faults occur at different locations based on the mode domain parameters of the line and other components, further comprising: Obtain the analog domain parameters of other components in the DC transmission system, including at least the DC voltage during normal operation , converter station equivalent impedance , current limiting reactance Etc., and calculate the equivalent impedance of the protected frequency-dependent DC line at different fault locations as seen from the line fault point ; Equivalent impedance There are three situations: line head end fault, line middle fault and line end fault; Ground mode equivalent impedance in three cases and line mode equivalent impedance The calculation formula is: ; Where, and They represent the system ground mode equivalent impedance on the back side of the line head end and the system ground mode equivalent impedance on the back side of the line end, and They represent the ground mode wave impedance and line mode wave impedance of the protected line respectively, || is the parallel symbol, and They represent the system line mode equivalent impedance at the back side of the line head end and the system line mode equivalent impedance at the back side of the line end respectively; Then, the line mode voltage division coefficient is obtained The calculation formula is as follows: ; Where, is the transition resistor.

4. The method for setting a fixed value of a single-ended transient voltage energy type DC line protection according to claim 1, characterized in that: The method further comprises: obtaining a line mode fault voltage transfer function based on the obtained line mode propagation constant and the line mode voltage division coefficient, which takes the fault voltage at the fault point as an excitation and the fault voltage at the protection installation as a response. Get the line mode reflection coefficient at the protection installation The calculation formula is: ; According to the parameters obtained in the above steps, calculate the line mode fault voltage transfer function with the fault voltage at the fault point as the excitation and the fault voltage at the protection installation as the response The calculation formula is: ; 5. The method for setting a fixed value of a single-ended transient voltage energy type DC line protection according to claim 1, characterized in that: Obtaining an extracted frequency band for setting transient variable protection, determining a weakest fault voltage transfer function within the frequency band to construct a voltage step function, further comprising: Using transient quantity to protect the lower limit of the extracted frequency band The weakest fault transfer function amplitude at frequency Multiply by the rated voltage Construct a voltage step function.

6. The method for setting a fixed value of a single-ended transient voltage energy type DC line protection according to claim 1, characterized in that: The transient energy is calculated by using the voltage step function to obtain the setting value of the DC line protection based on the single-ended voltage transient energy. The method further includes: calculating the transient energy of the voltage step function by using the single-ended voltage transient energy algorithm to obtain the transient energy value at the weakest fault. , the calculation formula for the setting value of DC line protection based on single-ended voltage transient energy is: , is the reliability coefficient.

7. A single-ended transient voltage energy type DC line protection setting value setting system that implements a single-ended transient voltage energy type DC line protection setting value setting method according to any one of claims 1 to 6, characterized in that: The system includes a line parameter calculation module, a line mode fault voltage frequency response analysis module, a weakest fault determination module within the area, and a fixed value setting calculation module; among which: The line parameter calculation module obtains line parameters of each frequency-dependent DC line in the DC transmission system, obtains ground mode wave impedance and line mode wave impedance based on the line parameters, and obtains line mode propagation constant based on the ground mode wave impedance and the line mode wave impedance; The line mode fault voltage frequency response analysis module implements line mode fault voltage frequency response analysis: i. Obtaining the mode domain parameters of other components in the DC transmission system, and calculating the equivalent impedance of the protected DC line at different fault locations as viewed from the line fault point according to the mode domain parameters of the line; ii. Using the equivalent impedance to obtain the line mode voltage divider coefficient of the voltage divider caused by the transition resistor and the mode domain network; iii. Based on the obtained line mode propagation constant and the line mode voltage divider coefficient, the fault voltage at the fault point is calculated as an excitation, and the line mode fault voltage transmission function of the protection installation at the fault voltage response is calculated; The weakest fault determination module in the area obtains the extracted frequency band of the set transient protection, determines the weakest fault voltage transfer function in the frequency band area, and constructs a voltage step function; The setting value calculation module calculates transient energy using the voltage step function to obtain a setting value for DC line protection based on single-ended voltage transient energy.

8. An electronic device comprising: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, a method for setting a fixed value of a single-ended transient voltage energy-type DC line protection according to any one of claims 1 to 6 is implemented.

9. A non-transitory computer-readable storage medium having a computer program stored thereon, wherein when the computer program is executed by a processor, the method for setting a fixed value of a single-ended transient voltage energy-type DC line protection according to any one of claims 1 to 6 is implemented.

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