A method for distinguishing a high-resistance grounding fault line and a related device

Abstract

The present application discloses a method for distinguishing a high-resistance grounding fault line and a related device, the method comprising: obtaining the zero-sequence voltage at the busbar, and when the zero-sequence voltage is less than a preset threshold, obtaining the zero-sequence current of each line; extracting the characteristic frequency band signal of the zero-sequence current of each line through S transformation; establishing a directional energy formula according to the amplitude sequence and phase angle sequence of the characteristic frequency band signal, and transforming the directional energy formula to obtain a directional energy matrix; calculating the directional energy proportion of each line based on the directional energy matrix, and judging whether the line is a fault line according to the directional energy proportion. Compared with the prior art, the high-resistance grounding fault line distinguishing method of the present application expands the traditional S transformation energy criterion, and also makes up for the shortcomings of insufficient applicability of the single line selection method, and can be applied to the single-phase grounding fault distinguishing of the resonant grounding system under different fault conditions, especially in the high-resistance grounding fault distinguishing, it has a good effect and strong applicability.

Description

Technical Field

[0001] The present application relates to the technical field of line selection and detection of high-resistance grounding faults in distribution networks, and in particular to a method for distinguishing high-resistance grounding fault lines and related devices. Background Art

[0002] When a single-phase grounding fault occurs due to resonant grounding, the fault current in the system is very weak due to the compensation effect of the arc suppression coil. Therefore, many scholars have cited signal feature extraction methods to solve such problems.

[0003] For example, the energy proportion method based on S transform or wavelet packet mainly determines the fault line by calculating the energy proportion of the characteristic frequency band signal of each line, where the line with large energy is the fault line. However, this method only uses the energy judgment of the characteristic frequency band signal, the judgment is single, and there is a situation where the judgment margin is not high when judging the high-resistance grounding fault. The correlation coefficient rule based on wavelet packet transform uses the waveform difference of the characteristic frequency band signal of each line to select the fault line. In essence, it still uses the principle of signal polarity to judge the fault line. This method, like the above, only uses the direction judgment in the characteristic frequency band signal, the judgment is single, and there is also a situation where the judgment margin is not high when judging the high-resistance grounding fault.

[0004] The discrimination rule based on information fusion uses multi-source information for fault discrimination. However, this method requires a large amount of historical data as support, and there will be overlapping features between multi-source signals, which does not have much effect on improving the judgment margin and defining the fault boundary. Summary of the invention

[0005] The present application provides a high-resistance grounding fault line identification method and related devices, which are used to solve the technical problems of the prior art that the judgment criterion is single and the judgment margin is not high.

[0006] In view of this, the first aspect of the present application provides a method for identifying a high-resistance grounding fault line, the method comprising:

[0007] Obtaining the zero-sequence voltage at the busbar, and when the zero-sequence voltage is less than a preset threshold, obtaining the zero-sequence current of each line;

[0008] Extract the characteristic frequency band signal of zero-sequence current of each line through S transformation;

[0009] According to the amplitude sequence and phase angle sequence of the characteristic frequency band signal, a directional energy formula is established, and the directional energy formula is transformed to obtain a directional energy matrix;

[0010] The directional energy proportion of each line is calculated based on the directional energy matrix, and whether the line is a faulty line is determined according to the directional energy proportion.

[0011] Optionally, establishing a directional energy formula according to the amplitude sequence and the phase angle sequence of the characteristic frequency band signal, and transforming the directional energy formula to obtain a directional energy matrix specifically includes:

[0012] According to the amplitude sequence and phase angle sequence of the characteristic frequency band signal, a directional energy formula is established, and the directional energy formula is transformed to obtain a directional energy matrix A;

[0013] Wherein, the directional energy formula is:

[0014]

[0015] In the formula, θ(i,j) xy is the sampling point S of the characteristic frequency band signal of the zero-sequence current of line x x (i, j) and the sampling point S of the characteristic frequency band signal of the zero-sequence current of line y y The phase angle difference of (i,j), a xy is the directional energy of line x relative to line y, that is, the square sum of the amplitude of each sampling point of line x minus the amplitude of the corresponding sampling point of line y and the cosine product of the phase angle difference between the two signals, real(S x (i,j))、angle(S x (i,j)) represent the amplitude and phase angle of the sampling point S(i,j) in the complex matrix respectively;

[0016] The directional energy matrix A is:

[0017]

[0018] Where q is the number of outgoing lines in the system, and the xth row can be expressed as the directional energy vector A of line x: x , where all the elements on the main diagonal are 0.

[0019] Optionally, calculating the directional energy proportion of each line based on the directional energy matrix, and judging whether the line is a faulty line according to the directional energy proportion specifically includes:

[0020] Constructing a criterion formula based on the directional energy matrix, calculating the directional energy ratio of the line according to the criterion formula, and judging that the line is a faulty line when the directional energy ratio is greater than a preset threshold;

[0021] Wherein, the criterion formula is:

[0022]

[0023] In the formula, ω x is the directional energy proportion of line x.

[0024] Optionally, extracting the characteristic frequency band signal of the zero-sequence current of each line through S transformation specifically includes:

[0025] The zero-sequence current is transformed by S transformation to obtain a discrete form formula of the zero-sequence current, the discrete form formula is transformed to obtain a complex matrix, and a characteristic frequency band signal of the zero-sequence current is extracted based on the complex matrix;

[0026] Among them, the discrete form formula is:

[0027]

[0028] In the formula, N is the number of sampling points, T is the sampling interval, l is the time parameter, and n is the frequency parameter;

[0029] The complex matrix is:

[0030]

[0031] Where S(i,j) is the jth sampling point at the i-th frequency.

[0032] A second aspect of the present application provides a high-resistance grounding fault line identification system, the system comprising:

[0033] An acquisition unit, used for acquiring a zero-sequence voltage at a busbar, and when the zero-sequence voltage is less than a preset threshold, acquiring a zero-sequence current of each line;

[0034] An extraction unit, used for extracting a characteristic frequency band signal of a zero-sequence current of each line through S transformation;

[0035] A calculation unit, used for establishing a directional energy formula according to the amplitude sequence and phase angle sequence of the characteristic frequency band signal, transforming the directional energy formula to obtain a directional energy matrix;

[0036] The determination unit is used to calculate the directional energy proportion of each line based on the directional energy matrix, and determine whether the line is a faulty line according to the directional energy proportion.

[0037] Optionally, the computing unit is specifically configured to:

[0038] According to the amplitude sequence and phase angle sequence of the characteristic frequency band signal, a directional energy formula is established, and the directional energy formula is transformed to obtain a directional energy matrix A;

[0039] Wherein, the directional energy formula is:

[0040]

[0041] Where θ(i,j) xy is the sampling point S of the characteristic frequency band signal of the zero-sequence current of line xx (i, j) and the sampling point S of the characteristic frequency band signal of the zero-sequence current of line y y The phase angle difference of (i,j), a xy is the directional energy of line x relative to line y, that is, the square sum of the amplitude of each sampling point of line x minus the amplitude of the corresponding sampling point of line y and the cosine product of the phase angle difference between the two signals, real(S x (i,j))、angle(S x (i,j)) represent the amplitude and phase angle of the sampling point S(i,j) in the complex matrix respectively;

[0042] The directional energy matrix A is:

[0043]

[0044] Where q is the number of outgoing lines in the system, and the xth row can be expressed as the directional energy vector A of line x: x , where all the elements on the main diagonal are 0.

[0045] Optionally, the determination unit is specifically used to:

[0046] Constructing a criterion formula based on the directional energy matrix, calculating the directional energy ratio of the line according to the criterion formula, and judging that the line is a faulty line when the directional energy ratio is greater than a preset threshold;

[0047] Wherein, the criterion formula is:

[0048]

[0049] In the formula, ω x is the directional energy proportion of line x.

[0050] Optionally, the extraction unit is specifically used to:

[0051] The zero-sequence current is transformed by S transformation to obtain a discrete form formula of the zero-sequence current, the discrete form formula is transformed to obtain a complex matrix, and a characteristic frequency band signal of the zero-sequence current is extracted based on the complex matrix;

[0052] Among them, the discrete form formula is:

[0053]

[0054] In the formula, N is the number of sampling points, T is the sampling interval, l is the time parameter, and n is the frequency parameter;

[0055] The complex matrix is:

[0056]

[0057] Where S(i,j) is the jth sampling point at the i-th frequency.

[0058] A third aspect of the present application provides a high-resistance grounding fault line identification device, the device comprising a processor and a memory:

[0059] The memory is used to store program code and transmit the program code to the processor;

[0060] The processor is used to execute the steps of the high-resistance grounding fault line identification method as described in the first aspect according to the instructions in the program code.

[0061] A fourth aspect of the present application provides a computer-readable storage medium, wherein the computer-readable storage medium is used to store program codes, and the program codes are used to execute the high-resistance grounding fault line identification method described in the first aspect.

[0062] It can be seen from the above technical solutions that this application has the following advantages:

[0063] The present application provides a method for distinguishing a high-resistance grounding fault line, including: obtaining the zero-sequence voltage at the bus, and when the zero-sequence voltage is less than a preset threshold, obtaining the zero-sequence current of each line; extracting the characteristic frequency band signal of the zero-sequence current of each line through S transformation; establishing a directional energy formula based on the amplitude sequence and phase angle sequence of the characteristic frequency band signal, transforming the directional energy formula to obtain a directional energy matrix; calculating the directional energy proportion of each line based on the directional energy matrix, and judging whether the line is a fault line based on the directional energy proportion. Compared with the prior art, the high-resistance grounding fault line distinguishing method of the present application expands the traditional S transformation energy criterion, and also makes up for the shortcomings of the insufficient applicability of the single line selection method. It can be applied to the single-phase grounding fault distinguishing of the resonant grounding system under different fault conditions, especially in the high-resistance grounding fault distinguishing, and has a good effect and strong applicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] Figure 1 A schematic diagram of a flow chart of a method for identifying a high-resistance grounding fault line provided in an embodiment of the present application;

[0065] Figure 2 This is a schematic diagram of the structure of a high-resistance grounding fault line identification system embodiment provided in an embodiment of the present application;

[0066] Figure 3 A simulation model diagram provided in an embodiment of the present application;

[0067] Figure 4 This is a distribution diagram of the frequency bands of each line provided in the embodiments of the present application. DETAILED DESCRIPTION

[0068] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0069] See also Figure 1 , a method for distinguishing a high-resistance grounding fault line provided in an embodiment of the present application includes:

[0070] Step 101, obtaining the zero-sequence voltage at the busbar, and when the zero-sequence voltage is less than a preset threshold, obtaining the zero-sequence current of each line;

[0071] It should be noted that the zero-sequence voltage U at the busbar is first obtained. 0 , if a single-phase grounding fault occurs, the zero-sequence voltage U 0 When it is less than 0.15 times of the system rated voltage Um, the zero-sequence current of each line is extracted.

[0072] Step 102: extracting the characteristic frequency band signal of the zero-sequence current of each line through S transformation;

[0073] It should be noted that S transform is a powerful signal feature extraction method, which can not only extract the amplitude information of the signal, but also the phase angle information.

[0074] If there is an original continuous signal x(t), its discrete form can be obtained by S transform as follows:

[0075]

[0076] Where N is the number of sampling points, T is the sampling interval, l is the time parameter, and n is the frequency parameter.

[0077] Further processing of the above formula will result in a complex matrix as follows:

[0078]

[0079] In the complex matrix, S(i,j) is the jth sampling point at the i-th frequency. If the entire complex matrix is ​​transformed into a triangular matrix, the amplitude sequence information and phase angle sequence information of each frequency can be decomposed.

[0080] Among them, the frequency band with the largest energy in all frequency signals is the characteristic frequency band, from which the characteristic frequency band of zero-sequence current of each line and the corresponding amplitude sequence information and phase angle sequence information can be extracted.

[0081] Step 103: establishing a directional energy formula according to the amplitude sequence and phase angle sequence of the characteristic frequency band signal, transforming the directional energy formula to obtain a directional energy matrix;

[0082] It should be noted that when a single-phase grounding fault occurs in the system, the transient zero-sequence current directions of the faulty line and the healthy line are opposite, and the amplitude of the former is much larger than the latter. The transient zero-sequence current characteristics of each healthy line are roughly the same, and the characteristic frequency band signal extracted after S transform has corresponding properties.

[0083] Assuming the ith frequency is the characteristic frequency band, the amplitude sequence of the line zero-sequence current characteristic frequency band signal can be expressed as {real(S x (i,1)),real(S x (i,2)),…,real(S x (i,N))}, the phase angle sequence of the line zero-sequence current characteristic frequency band signal can be expressed as {angle(S x (i,1)),angle(S x (i,2)),…,angle(S x (i,N))}, where real(S x (i,j))、angle(S x (i,j)) represent the amplitude and phase angle of the sampling point S(i,j) in the complex matrix respectively.

[0084] Since the amplitude of the zero-sequence current characteristic frequency band of the fault line is much larger than that of the sound current, and the directions of the two are roughly opposite, while the direction of the zero-sequence current characteristic frequency band signal of the sound line is the same and the amplitude difference is not large, in order to integrate the direction and amplitude characteristics and improve the fault boundary, the concept of directional energy is proposed. The specific formula is as follows:

[0085] θ(i,j) xy =angle(S x (i,j))-angle(S y (i,j))

[0086] Where θ(i,j) xy is the sampling point S of the zero-sequence current characteristic frequency band of line x x (i, j) and line y zero-sequence current characteristic frequency band sampling point S y The phase angle difference of (i,j), a xy It is the directional energy of line x relative to line y, that is, the sum of the squares of the amplitude of each sampling point on line x minus the amplitude of the corresponding sampling point on line y multiplied by the cosine of the phase difference between the two signals.

[0087] Then the directional energy matrix A can be obtained as follows:

[0088]

[0089] Where q is the number of outgoing lines in the system, and the xth row can be expressed as the directional energy vector A of line x: x , where all the elements on the main diagonal are 0.

[0090] Step 104: Calculate the directional energy proportion of each line based on the directional energy matrix, and determine whether the line is a faulty line according to the directional energy proportion.

[0091] It should be noted that, since the cosine of the phase angle difference between the faulty line and the sound line is close to -1, and the cosine of the phase angle difference between the sound lines is close to 1, it can be seen that the minimum value of the directional energy vector of the faulty line, except for the 0 element, has been improved to a certain extent compared with the traditional energy, while the sound line has decreased compared with the traditional energy, and the former is much greater than the latter. Therefore, the proportion of directional energy can be used to identify the faulty line. The judgment formula is as follows:

[0092]

[0093] Where ω x is the directional energy proportion of line x.

[0094] From the above judgment formula, we can know that the directional energy ratio of the faulty line is close to 1, while the healthy line is close to 0. If a threshold value ω is set set , then when a single-phase grounding fault occurs in the system set <ω x , it can be determined that line x is a faulty line, otherwise it is a sound line, so the fault boundary can be well defined.

[0095] The following is a brief description of the embodiment of the present application using a 10kV distribution network resonant grounding system model as an example:

[0096] There are 5 outgoing lines in total. The types, lengths and line parameters of each outgoing line are shown in Table 1 and Table 2 respectively. The arc suppression coil adopts overcompensation mode with a compensation degree of 8% and a sampling frequency of 10kHz. The specific simulation model is shown in the figure Figure 2 shown.

[0097] Table 1 System model line parameters

[0098] Feeder Type <![CDATA[R 1 / Oh]]> <![CDATA[L 1 / mH]]> <![CDATA[C 1 / uF]]> <![CDATA[R 0 / Oh]]> <![CDATA[L 0 / mH]]> <![CDATA[C 0 / uF]]> Overhead lines 0.175 1.210 0.01 0.23 5.478 0.008 cable 0.270 0.354 0.339 2.70 1.019 0.280

[0099] Table 2 Line length details and load conditions

[0100] Line length <![CDATA[L 1 ]]> <![CDATA[L 2 ]]> <![CDATA[L 3 ]]> <![CDATA[L 4 ]]> <![CDATA[L 5 ]]> Overhead lines (km) 12 5 0 0 20 Cable(km) 0 5 10 15 0

[0101] Now simulate a single-phase ground fault with a ground resistance of 2000Ω and a fault closing angle of 90° at 50% of line 1. By performing S transformation on the zero-sequence current of each line, the amplitude sequence and phase angle sequence of each frequency can be obtained. The energy distribution of each frequency band of line 1 to line 4 is as follows: Figure 4 As shown in the energy distribution diagram, it can be seen that the energy of the second frequency band is the largest, so the second frequency band is used as the characteristic frequency band.

[0102] Now we can use the amplitude sequence and phase angle sequence of each line characteristic frequency band to calculate the directional energy matrix according to the formula as follows:

[0103]

[0104] From the directional energy matrix, we can see that the main diagonal elements are 0, and the minimum value of the directional energy vector of the faulty line, except for the 0 element, is much larger than the minimum value of the directional energy vector of the healthy line, except for the 0 element. Then, the directional energy proportions of each line are calculated by the formula to be [0.858, 0.030, 0.040, 0.042, 0.030], respectively. From the directional energy proportions of each line, we can see that the directional energy proportion of line 1, i.e. the faulty line, is close to 1, while the rest of the lines, i.e. the healthy lines, are all close to 0, thus forming the protection criterion. It can be seen that the criterion proposed in this paper can relatively more clearly define the fault boundary and can well distinguish the faulty line from the healthy line.

[0105] In order to further verify the applicability of the protection criterion proposed in this paper, especially the discrimination effect in high-resistance grounding, the single-phase high-resistance grounding fault under different fault conditions is analyzed. The specific fault conditions and the corresponding energy proportions of each line direction are shown in Table 3.

[0106] Table 3 Results of energy proportion of each line direction under different fault conditions

[0107]

[0108] From the results of the directional energy proportion of each line in Table 3, it can be seen that no matter under what fault conditions a single-phase grounding fault occurs, the directional energy proportion corresponding to the faulty line is close to 1, and the directional energy proportion of the sound line is close to 0, that is, the directional energy proportion of the faulty line is much greater than the directional energy proportion of the sound line. Therefore, the faulty line can be better identified and is not affected by various fault conditions, which has a good application prospect.

[0109] The above is a high-resistance grounding fault line identification method provided in an embodiment of the present application, and the following is a high-resistance grounding fault line identification system provided in an embodiment of the present application.

[0110] See also Figure 2, a high-resistance grounding fault line identification system provided in an embodiment of the present application includes:

[0111] An acquisition unit 201 is used to acquire the zero-sequence voltage at the busbar, and when the zero-sequence voltage is less than a preset threshold, the zero-sequence current of each line is acquired;

[0112] An extraction unit 202, used to extract a characteristic frequency band signal of a zero-sequence current of each line through S transformation;

[0113] The calculation unit 203 is used to establish a directional energy formula according to the amplitude sequence and phase angle sequence of the characteristic frequency band signal, and transform the directional energy formula to obtain a directional energy matrix;

[0114] The determination unit 204 is used to calculate the directional energy proportion of each line based on the directional energy matrix, and determine whether the line is a faulty line according to the directional energy proportion.

[0115] Furthermore, in an embodiment of the present application, a high-resistance grounding fault line identification device is provided, the device comprising a processor and a memory:

[0116] The memory is used to store program code and transmit the program code to the processor;

[0117] The processor is used to execute the high-resistance grounding fault line identification method described in the above method embodiment according to the instructions in the program code.

[0118] Furthermore, a computer-readable storage medium is provided in an embodiment of the present application. The computer-readable storage medium is used to store program codes, and the program codes are used to execute the high-resistance grounding fault line identification method described in the above method embodiment.

[0119] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0120] The terms "first", "second", "third", "fourth", etc. (if any) in the specification of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein, for example. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0121] It should be understood that in the present application, "at least one (item)" means one or more, and "plurality" means two or more. "And / or" is used to describe the association relationship of associated objects, indicating that three relationships may exist. For example, "A and / or B" can mean: only A exists, only B exists, and A and B exist at the same time, where A and B can be singular or plural. The character " / " generally indicates that the objects associated before and after are in an "or" relationship. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, at least one of a, b or c can mean: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, c can be single or multiple.

[0122] In the several embodiments provided in the present application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or units, which can be electrical, mechanical or other forms.

[0123] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0124] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0125] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application is essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (full name in English: Read-Only Memory, English abbreviation: ROM), random access memory (full name in English: Random Access Memory, English abbreviation: RAM), disk or optical disk and other media that can store program codes.

[0126] As described above, the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for identifying a high-resistance grounding fault line, characterized in that: include: Obtaining the zero-sequence voltage at the busbar, and when the zero-sequence voltage is less than a preset threshold, obtaining the zero-sequence current of each line; Extract the characteristic frequency band signal of zero-sequence current of each line through S transformation; According to the amplitude sequence and phase angle sequence of the characteristic frequency band signal, a directional energy formula is established, and the directional energy formula is transformed to obtain a directional energy matrix; Calculate the directional energy proportion of each line based on the directional energy matrix, and determine whether the line is a faulty line according to the directional energy proportion; The step of establishing a directional energy formula according to the amplitude sequence and phase angle sequence of the characteristic frequency band signal and transforming the directional energy formula to obtain a directional energy matrix specifically includes: According to the amplitude sequence and phase angle sequence of the characteristic frequency band signal, a directional energy formula is established, and the directional energy formula is transformed to obtain a directional energy matrix A; Wherein, the directional energy formula is: ； ； In the formula, is the sampling point of the characteristic frequency band signal of the zero-sequence current of line x The sampling point of the characteristic frequency band signal of the zero-sequence current of line y The phase angle difference, is the directional energy of line x relative to line y, that is, the sum of the squares of the product of the amplitude of each sampling point of line x minus the amplitude of the corresponding sampling point of line y and the cosine of the phase angle difference between the two signals, , Represents the complex matrix Amplitude and phase angle of sampling points; The directional energy matrix A is: ； Where q is the number of outgoing lines in the system, and the xth row can be expressed as the directional energy vector of line x: , where all the main diagonal elements are 0; The extracting of the characteristic frequency band signal of the zero-sequence current of each line by S transformation specifically includes: The zero-sequence current is transformed by S transformation to obtain a discrete form formula of the zero-sequence current, the discrete form formula is transformed to obtain a complex matrix, and a characteristic frequency band signal of the zero-sequence current is extracted based on the complex matrix; Among them, the discrete form formula is: ； Where N is the number of sampling points, T is the sampling interval, is the time parameter, n is the frequency parameter; The complex matrix is: ； In the formula, is the jth sampling point at the ith frequency.

2. The method for identifying a high-resistance grounding fault line according to claim 1, characterized in that: The calculating the directional energy proportion of each line based on the directional energy matrix, and judging whether the line is a faulty line according to the directional energy proportion specifically includes: Constructing a criterion formula based on the directional energy matrix, calculating the directional energy ratio of the line according to the criterion formula, and judging that the line is a faulty line when the directional energy ratio is greater than a preset threshold; Wherein, the criterion formula is: ； In the formula, is the directional energy proportion of line x.

3. A high-resistance grounding fault line identification system, characterized in that: include: An acquisition unit, used for acquiring a zero-sequence voltage at a busbar, and when the zero-sequence voltage is less than a preset threshold, acquiring a zero-sequence current of each line; An extraction unit, used for extracting a characteristic frequency band signal of a zero-sequence current of each line through S transformation; A calculation unit, used for establishing a directional energy formula according to the amplitude sequence and phase angle sequence of the characteristic frequency band signal, transforming the directional energy formula to obtain a directional energy matrix; A determination unit, configured to calculate a directional energy ratio of each line based on the directional energy matrix, and determine whether the line is a faulty line according to the directional energy ratio; Wherein, the computing unit is specifically used for: According to the amplitude sequence and phase angle sequence of the characteristic frequency band signal, a directional energy formula is established, and the directional energy formula is transformed to obtain a directional energy matrix A; Wherein, the directional energy formula is: ； ； In the formula, is the sampling point of the characteristic frequency band signal of the zero-sequence current of line x The sampling point of the characteristic frequency band signal of the zero-sequence current of line y The phase angle difference, is the directional energy of line x relative to line y, that is, the sum of the squares of the product of the amplitude of each sampling point of line x minus the amplitude of the corresponding sampling point of line y and the cosine of the phase angle difference between the two signals, , Represents the complex matrix Amplitude and phase angle of sampling points; The directional energy matrix A is: ； Where q is the number of outgoing lines in the system, and the xth row can be expressed as the directional energy vector of line x: , where all the main diagonal elements are 0; The extraction unit is specifically used for: The zero-sequence current is transformed by S transformation to obtain a discrete form formula of the zero-sequence current, the discrete form formula is transformed to obtain a complex matrix, and a characteristic frequency band signal of the zero-sequence current is extracted based on the complex matrix; Among them, the discrete form formula is: ； Where N is the number of sampling points, T is the sampling interval, is the time parameter, n is the frequency parameter; The complex matrix is: ； In the formula, is the jth sampling point at the ith frequency.

4. The high-resistance grounding fault line identification system according to claim 3 is characterized in that: The discrimination unit is specifically used for: Constructing a criterion formula based on the directional energy matrix, calculating the directional energy ratio of the line according to the criterion formula, and judging that the line is a faulty line when the directional energy ratio is greater than a preset threshold; Wherein, the criterion formula is: ； In the formula, is the directional energy proportion of line x.

5. A high-resistance grounding fault line identification device, characterized in that: The device comprises a processor and a memory: The memory is used to store program code and transmit the program code to the processor; The processor is used to execute the high-resistance grounding fault line identification method according to any one of claims 1-2 according to the instructions in the program code.

6. A computer-readable storage medium, characterized in that: The computer-readable storage medium is used to store program codes, and the program codes are used to execute the high-resistance grounding fault line identification method according to any one of claims 1-2.

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