Single-phase earth fault positioning method and system based on zero-sequence current integration

Abstract

The invention discloses a single-phase earth fault positioning method and system based on zero-sequence current integration, and the method comprises the steps: recording fault transient zero-sequence current data within 0.04 s after a fault occurs at each detection point on a line after the single-phase earth occurs on the line; the method comprises the following steps: firstly, filtering fault transient zero-sequence current data acquired by each detection point within a set period to obtain transient data, then calculating an amplitude within a set time period after a fault, and generating a transient zero-sequence current amplitude sequence of each detection point; the main station calculates a transient zero-sequence current amplitude integral coefficient and an amplitude comprehensive difference coefficient of the detection points at the two ends of each section on the fault line by using the uploaded transient zero-sequence current amplitude sequence data; and the master station carries out positioning according to the calculated transient zero-sequence current amplitude integral coefficient and amplitude comprehensive difference coefficient of each section. The system comprises a data acquisition module, a data processing module, a calculation module and a positioning module. The method can judge the fault section according to the amplitude integral coefficient.

Description

Technical Field

[0001] The invention belongs to the technical field of line fault detection, and in particular relates to a single-phase grounding fault locating method based on zero-sequence current integration. Background Art

[0002] At present, most 3~66kV medium-voltage distribution networks are operated in a neutral point ungrounded system or a neutral point grounded through an arc-extinguishing winding. When a single-phase grounding fault occurs, the fault phase voltage will be lower than the normal voltage, and the non-fault phase voltage will increase. However, since the line voltage remains symmetrical and the current at the fault point is weak, the distribution network will continue to operate in an abnormal working state for 1~2 hours. If the fault point cannot be discovered and handled in time, a long period of abnormal operation will lead to further breakdown at the weak point of the line, causing a greater accident. Among the types of grounding faults, more than 80% are single-phase grounding faults, which are characterized by a small amplitude of the grounding current and are not easy to detect when a fault occurs, so it is more difficult to determine the fault point than other faults. Summary of the invention

[0003] The present invention provides a single-phase grounding fault location method and system based on zero-sequence current integration. The zero-sequence current data within two power frequency cycles after the fault occurs on both sides of each section are used to calculate the amplitude in different time periods, and the amplitude integral coefficient is obtained by using an integral algorithm, and finally the fault section is determined according to the amplitude integral coefficient.

[0004] In order to achieve the above object, the present invention adopts the following technical solution: The single-phase grounding fault location method based on zero-sequence current integration includes: After a single-phase ground fault occurs on the line, each detection point on the line records the transient zero-sequence current data within 0.04s after the fault occurs; Each detection point first performs filtering on the fault transient zero-sequence current data collected within the set period to obtain transient data, then calculates the amplitude within the set time period after the fault, generates the transient zero-sequence current amplitude sequence of each detection point, and uploads the transient zero-sequence current amplitude sequence to the master station; The master station uses the uploaded transient zero-sequence current amplitude sequence data to calculate the transient zero-sequence current amplitude integral coefficient and amplitude comprehensive difference coefficient of the detection points at both ends of each section on the fault line; The master station performs positioning based on the calculated transient zero-sequence current amplitude integral coefficient and amplitude comprehensive difference coefficient of each section.

[0005] A further improvement of the present invention is that each detection point first performs filtering processing on the fault transient zero-sequence current data collected within two cycles to obtain transient data.

[0006] A further improvement of the present invention is that the amplitudes in eight time periods after a fault are calculated to generate a transient zero-sequence current amplitude sequence at each detection point.

[0007] A further improvement of the present invention is that the master station performs positioning based on the calculated transient zero-sequence current amplitude integral coefficient and amplitude comprehensive difference coefficient of each section, and the judgment method is: when the transient zero-sequence current amplitude comprehensive difference coefficient δ is less than the set threshold δset, it is judged that a fault has occurred at the end of the line.

[0008] A further improvement of the present invention is that the master station locates the fault section according to the calculated transient zero-sequence current amplitude integral coefficient and the amplitude comprehensive difference coefficient of each section, and the judgment method is: if the transient zero-sequence current amplitude comprehensive difference correlation coefficient is greater than the set threshold δset, the section corresponding to the maximum value of the transient zero-sequence current amplitude integral coefficient is selected as the fault section.

[0009] A further improvement of the present invention is that the master station performs positioning according to the calculated transient zero-sequence current amplitude integral coefficient and amplitude comprehensive difference coefficient of each section, and the judgment method is: setting the threshold δset=0.1, which can be adjusted according to the actual site and the accuracy of the detection equipment.

[0010] The single-phase ground fault location system based on zero-sequence current integration includes: The data acquisition module is used to record the transient zero-sequence current data of the fault within 0.04s after the fault occurs at each detection point on the line after the single-phase grounding occurs on the line; The data processing module is used for filtering the transient zero-sequence current data collected within the set period at each detection point to obtain transient data, and then calculating the amplitude within the set time period after the fault, generating the transient zero-sequence current amplitude sequence of each detection point, and uploading the transient zero-sequence current amplitude sequence to the main station; A calculation module is used for the master station to calculate the transient zero-sequence current amplitude integral coefficient and the amplitude comprehensive difference coefficient of the detection points at both ends of each section on the fault line using the uploaded transient zero-sequence current amplitude sequence data; The positioning module is used for the master station to perform positioning according to the calculated transient zero-sequence current amplitude integral coefficient and amplitude comprehensive difference coefficient of each section.

[0011] A further improvement of the present invention is that, in the data processing module, each detection point first performs filtering processing on the fault transient zero-sequence current data collected within two cycles to obtain transient data.

[0012] A further improvement of the present invention is that, in the data processing module, the amplitudes in eight time periods after the fault are calculated to generate a transient zero-sequence current amplitude sequence at each detection point.

[0013] A further improvement of the present invention is that, in the positioning module, the master station performs positioning according to the calculated transient zero-sequence current amplitude integral coefficient and amplitude comprehensive difference coefficient of each section, and the judgment method is: when the transient zero-sequence current amplitude comprehensive difference coefficient δ is less than the set threshold δset, it is judged that a fault has occurred at the end of the line.

[0014] Compared with the prior art, the present invention has at least the following beneficial technical effects: The present invention provides a single-phase grounding fault location method and system based on zero-sequence current integration, which has the advantages of small algorithm calculation and easy signal acquisition; high positioning accuracy for single-phase grounding faults under different grounding resistances, different compensation degrees, and different fault initial phase angles; in addition, it can still be applied to high-resistance grounding, line end grounding, and arc grounding faults. The method calculates the amplitude in parallel in different time periods, the algorithm is simple, and the positioning speed is fast; the integral algorithm is used to obtain the amplitude integral coefficient, and the fault recognition is high; only the zero-sequence current signal on the line is required, and the signal acquisition is convenient, which is also in line with the trend of further development of smart distribution networks. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a schematic diagram of the system equivalent zero-sequence network provided by the present invention.

[0016] Figure 2 This is a schematic diagram of transient zero-sequence current provided by the present invention.

[0017] Figure 3 It is a fault schematic diagram provided by the present invention.

[0018] Figure 4 This is the fault transient zero-sequence current waveform provided by the present invention.

[0019] Figure 5 It is a schematic diagram of the amplitude distribution of the fault transient zero-sequence current in different time periods provided by the present invention.

[0020] Figure 6 This is the fault transient zero-sequence current waveform provided by the present invention.

[0021] Figure 7 It is the time-division amplitude distribution curve of the fault transient zero-sequence current provided by the present invention.

[0022] Figure 8 It is a flow chart of the positioning algorithm provided by the present invention.

[0023] Fig. 9 The structure block diagram of the single-phase grounding fault location system based on zero-sequence current integration of the present invention. DETAILED DESCRIPTION

[0024] In the following, only some exemplary embodiments are briefly described. As those skilled in the art will appreciate, the described embodiments may be modified in various ways without departing from the spirit or scope of the present invention. Therefore, the drawings and descriptions are considered to be exemplary and non-restrictive in nature.

[0025] It should be understood that when used in this specification and the appended claims, the terms "include" and "comprises" indicate the presence of described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0026] It should also be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0027] It should be further understood that the term "and / or" used in the present description and the appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0028] Various structural schematic diagrams of the embodiments disclosed in the present invention are shown in the accompanying drawings. These figures are not drawn to scale, and some details are magnified and some details may be omitted for the purpose of clear expression. The shapes of various regions and layers shown in the figures and the relative sizes and positional relationships therebetween are only exemplary, and may deviate in practice due to manufacturing tolerances or technical limitations, and those skilled in the art may additionally design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0029] The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0030] Example 1 The single-phase grounding fault location method based on zero-sequence current integration provided by the present invention includes: After a single-phase ground fault occurs on the line, each detection point on the line records the transient zero-sequence current data within 0.04s after the fault occurs; Each detection point first filters the fault transient zero-sequence current data collected within two cycles to obtain transient data, then calculates the amplitude within 8 time periods after the fault, generates the transient zero-sequence current amplitude sequence of each detection point, and uploads the transient zero-sequence current amplitude sequence to the master station; The master station uses the uploaded transient zero-sequence current amplitude sequence data to calculate the transient zero-sequence current amplitude integral coefficient and amplitude comprehensive difference coefficient of the detection points at both ends of each section on the fault line; The master station performs positioning based on the calculated transient zero-sequence current amplitude integral coefficient and amplitude comprehensive difference coefficient of each section.

[0031] In this embodiment, the master station performs positioning according to the calculated transient zero-sequence current amplitude integral coefficient and amplitude comprehensive difference coefficient of each section, and the judgment method is: When the transient zero-sequence current amplitude comprehensive difference coefficient δ is less than the set threshold δset, it is determined that a fault occurs at the end of the line; If the transient zero-sequence current amplitude comprehensive difference correlation coefficient is greater than the set threshold δset, the section corresponding to the maximum value of the transient zero-sequence current amplitude integral coefficient is selected as the fault section; The threshold δset is set to 0.1, which can be adjusted according to the actual situation on site and the accuracy of the detection equipment.

[0032] Example 2 The single-phase grounding fault location method based on zero-sequence current integration provided by the present invention includes three parts, namely, location principle, signal acquisition, and location process, and each part is specifically described as follows.

[0033] 1. Positioning principle Since the long-term integration numerical mode will cause the accumulation of mode errors, the simulation quantity cannot reflect the real situation truthfully. It is necessary to introduce the zero-sequence current amplitude information into the amplitude integration method. The amplitude integration method is to divide the original time period into several small time intervals. At the end of each time interval, the amplitude integration coefficient is calculated using the fault transient zero-sequence current amplitude distribution sequence of two adjacent detection points. And the shorter the selected time interval, the higher the accuracy will be, and the more ideal the simulation results will be.

[0034] After a single-phase grounding fault occurs in the system, the zero-sequence equivalent network is as follows: Figure 1 . is the fault point, It is the detection point on the line. , is the equivalent resistance and reactance of the arc suppression coil. It is the zero-sequence power supply during fault. C01, C02, C03 are the capacitances of lines L1, L2, L3 to ground. C1, C2, C3, C4 are the capacitances of L4 line MN, NF, FP, PQ sections to ground.

[0035] In a system with an ungrounded neutral point, when a fault occurs, Current flowing out of the point The expression is as follows:

[0036]

[0037] Where: , is the sum of the currents of non-fault lines to ground; for Section ground current; is the current to ground through point Q; It is the ground current of PQ section.

[0038] The total length of the upstream line and the non-fault line at the fault end of the distribution network is much longer than the length of the downstream line. Therefore, the zero-sequence current flowing before the fault point is much larger than the zero-sequence current after the fault point.

[31] ,Right now , the zero-sequence current amplitude and waveform at both ends of the fault point are quite different. The zero-sequence current flowing through the detection points M and N has the following relationship:

[0039] because The distance between the two segments is short, and the capacitive current to ground can be ignored, so The zero-sequence currents detected at the points are approximately equal.

[0040] The zero-sequence current flowing through the detection points P and Q has the following relationship:

[0041] By the same token, the zero-sequence currents detected at points P and Q in the PQ section are also approximately equal.

[0042] In summary, when a single-phase grounding fault occurs in the distribution network, the transient zero-sequence current waveforms flowing through adjacent detection points on the same side before (or after) the fault point are similar, and the calculated amplitude difference is small; while the transient zero-sequence current waveforms flowing through the detection points on both sides of the fault point are greatly different, and the calculated amplitude difference is large. Figure 1 midpoint Take a fault as an example, the transient zero-sequence current waveform diagram of each section of the fault line is as follows: Figure 2 shown.

[0043] Similarly, for a line with 6 detection points, a single-phase grounding fault occurs between detection points 3 and 4. Figure 3 As shown. At this time, the transient zero-sequence current waveform of the fault is as follows Figure 4 The amplitude distribution is shown in Figure 5 shown.

[0044] Combined with the previous analysis, it can be seen that when a single-phase grounding fault occurs in the neutral point grounding system through an arc suppression coil, the transient zero-sequence current waveform difference between the detection points on the opposite sides of the fault point upstream and downstream is large; the transient zero-sequence current waveform difference between the detection points on the same side of the upstream and downstream is small.

[0045] In order to make full use of the amplitude of the transient zero-sequence current signal of the fault, the amplitude of the transient zero-sequence current data within 0.04s after the fault occurs is calculated in segments to obtain the amplitude distribution sequence. The calculation formula of the transient zero-sequence current amplitude in each period is:

[0046] is the transient zero-sequence current amplitude in the mth time period, n is the number of data sampling points of the transient zero-sequence current in the mth time period, is the transient zero-sequence current, where m=1,2,3,…,8. In order to reflect the amplitude difference between adjacent detection points, such as: I01 ={ I01 (1) I01 (2) I01 (3) I01 (4) I01 (5) , I01 (6) , I01 (7) , I01 (8)}, I02 ={ I02 (1) I02 (2) I02 (3) I02 (4) , I02 (5) , I02 (6) , I02 (7) , I02 (8)}, the calculation formula E of the amplitude integral coefficient is defined as:

[0047] E ( I 1, I 2) is the amplitude integral coefficient, , is the fault transient zero-sequence current amplitude distribution sequence of two adjacent detection points.

[0048] When a single-phase grounding fault occurs, the transient current amplitude distribution of the fault phase at the detection points at both ends of the non-fault section is close, and the amplitude integral coefficient is small. The transient current amplitude flowing through the detection points at both ends of the fault section is significantly different, and the amplitude integral coefficient is large. Therefore, the fault section location criterion is: the section corresponding to the maximum value of the zero-sequence current amplitude integral coefficient on the fault line is the fault section.

[0049] When a ground fault occurs at the end of a primary line, the rated zero-sequence current waveform is as follows: Figure 6 The distribution of the ground fault amplitude at the end of the primary line is shown in Figure 7 As shown. Figure 6 and Figure 7 It can be seen that when a single-phase grounding fault occurs at the end of the line, the zero-sequence current waveforms between adjacent detection points on the entire fault line are similar, and the amplitude integral coefficients obtained in each section are slightly different. For this reason, the amplitude integral difference coefficient is defined to represent the difference between the zero-sequence current amplitude integral coefficients calculated in each section. When the amplitude integral difference coefficient is less than the set threshold, it is determined that a single-phase grounding fault occurs at the end of the line. The calculation formula of the amplitude integral difference coefficient δ is:

[0050] Where δ is the amplitude integral difference coefficient, is the maximum value of the amplitude integral coefficient of each section of the fault line, It is the minimum value of the amplitude integral coefficient of each section of the fault line.

[0051] 2. Signal acquisition Since the positioning method used only uses the transient zero-sequence current of the fault on the line, the signal acquisition only needs to rely on the zero-sequence current transformer on the line or use the three-phase current synthesis method. In actual field practice, most urban distribution networks have been automated and intelligent, so the automatic terminals installed on the line can be used to collect zero-sequence current. Compared with the positioning method using voltage and current signals, this method only needs to use zero-sequence current data, and the signal acquisition is simple, avoiding the cost investment and ferromagnetic resonance caused by the installation of voltage transformers on the line. In addition, the use of zero-sequence current amplitude for calculation can reduce the problem of data acquisition synchronization.

[0052] The fault zero-sequence current can be divided into transient component and steady-state component according to the frequency component. The transient component has a high frequency, up to thousands of hertz, and the steady-state component is 50Hz. In order to obtain the transient zero-sequence current, the fault zero-sequence current must be filtered to remove the DC component and the power frequency component.

[0053] 3. Positioning process Take a photovoltaic power station as an example: Step 1: After a single-phase ground fault occurs on the line, each detection point on the line records the fault zero-sequence current data within 0.04s after the fault occurs; Step 2: Each detection point first performs filtering on the fault transient zero-sequence current data collected within two cycles to obtain transient data, and then calculates the amplitude within 8 time periods after the fault to generate the transient zero-sequence current amplitude sequence of each detection point, and uploads the amplitude sequence to the master station; Step 3: The master station uses the uploaded amplitude sequence data to calculate the transient zero-sequence current amplitude integral coefficient and amplitude comprehensive difference coefficient of the detection points at both ends of each section on the fault line; Step 4: The master station locates the transient zero-sequence current amplitude integral coefficient and amplitude comprehensive difference coefficient of each section according to the calculation. The specific criteria are as follows: 1. When the transient zero-sequence current amplitude comprehensive difference coefficient δ is less than the set threshold δset, it is determined that a fault has occurred at the end of the line; 2. If the transient zero-sequence current amplitude comprehensive difference correlation coefficient is greater than the set threshold δset, the section corresponding to the maximum value of the transient zero-sequence current amplitude integral coefficient is selected as the fault section.

[0054] Set the threshold δset=0.1, which can be adjusted according to the actual situation on site and the accuracy of the detection equipment. The process of fault location is as follows: Figure 8 shown.

[0055] For ease of understanding, the solution in this embodiment is verified and analyzed in detail in combination with simulation data: To line The following three fault conditions are set to simulate and verify the feasibility and accuracy of the positioning algorithm. Fault condition 1: The fault point is located in the [1,2] section; Fault condition 2: The fault point is located in the [3,4] section; Fault condition 3: The fault point is located in the [5,6] section. Different fault initial phase angles and different grounding transition resistances are simulated respectively. The sampling frequency of each measurement module is 20kHz. The data within two power frequency cycles after the fault occurs are selected for calculation. The processing results are shown in Table 1.

[0056] Table 1 General grounding data processing results

[0057] It can be seen from the general grounding data processing results in Table 1 that when single-phase grounding faults occur in sections 1, 3, and 5 (fault sections [1,2], [3,4], and [5,6]), the obtained amplitude comprehensive difference coefficient δ value is greater than δset, and the transient zero-sequence current amplitude integral coefficient value E of the fault section is the largest, which is much larger than the transient zero-sequence current amplitude integral coefficient of the non-fault section, and the positioning result is accurate.

[0058] (2) Analysis of grounding fault at the end of the line In order to verify the adaptability of the positioning algorithm to the ground fault at the end of the line, a line When a single-phase grounding fault occurs at the terminal with different grounding resistances and initial phase angles, the data processing results are shown in Table 2.

[0059]

[0060] From the data processing results of the line end grounding in Table 2, it can be seen that when a single-phase grounding occurs at the end of the line, the amplitude integral coefficients calculated in each section are not much different. At this time, the value of the amplitude comprehensive difference coefficient δ is much smaller than δset=0.1, and it is determined that a fault occurs at the end of the line, and the positioning is accurate.

[0061] (3) Analysis of intermittent ground fault Among the single-phase grounding faults that occur in the distribution network, a large proportion are intermittent grounding faults rather than permanent faults, among which arc grounding faults are the most common. In order to verify the universality of the designed positioning principle and positioning algorithm for arc grounding faults, the Cassie arc model is established and added to the single-phase grounding fault module. The data processing results after simulation are shown in Table 3.

[0062] Table 3 Intermittent grounding data processing results

[0063] It can be seen from the intermittent grounding data in Table 3 that when arc single-phase grounding faults occur in line sections 1, 3, and 5 (fault sections are [1,2], [3,4], and [5,6]), the calculated amplitude comprehensive difference coefficient δ is much larger than δset=0.1, and the transient zero-sequence current amplitude integral coefficient E of the fault section is the largest, much larger than the transient zero-sequence current amplitude integral coefficient of the non-fault section, and the positioning result is also accurate.

[0064] Through the above experiments, it can be known that according to the fault zero-sequence current after the single-phase grounding fault occurs, the zero-sequence current amplitude integral coefficient of each section is calculated by section, and the amplitude integral coefficient is used to locate the fault, where the section corresponding to the maximum value of the amplitude integral coefficient is the fault section. This method has the advantages of small algorithm calculation and easy signal acquisition; it has high positioning accuracy for single-phase grounding faults under different grounding resistances, different compensation degrees, and different fault initial phase angles; in addition, it can still be applied to high-resistance grounding, line end grounding, and arc grounding faults.

[0065] Example 3 like Fig. 9 As shown, the single-phase grounding fault location system based on zero-sequence current integration provided by the present invention includes: The data acquisition module is used to record the transient zero-sequence current data of the fault within 0.04s after the fault occurs at each detection point on the line after the single-phase grounding occurs on the line; The data processing module is used for filtering the transient zero-sequence current data collected within the set period at each detection point to obtain transient data, and then calculating the amplitude within the set time period after the fault, generating the transient zero-sequence current amplitude sequence of each detection point, and uploading the transient zero-sequence current amplitude sequence to the main station; A calculation module is used for the master station to calculate the transient zero-sequence current amplitude integral coefficient and the amplitude comprehensive difference coefficient of the detection points at both ends of each section on the fault line using the uploaded transient zero-sequence current amplitude sequence data; The positioning module is used for the master station to perform positioning according to the calculated transient zero-sequence current amplitude integral coefficient and amplitude comprehensive difference coefficient of each section.

[0066] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is defined by the attached claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention. Any figure mark in the claims should not be regarded as limiting the claims involved.

[0067] In addition, it should be understood that although this specification is described in accordance with the implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation modes that can be understood by those skilled in the art. The above content is only to illustrate the technical idea of ​​the present invention, and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution according to the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A single-phase ground fault location method based on zero-sequence current integration, characterized in that: include: After a single-phase ground fault occurs on the line, each detection point on the line records the transient zero-sequence current data within 0.04s after the fault occurs; Each detection point first performs filtering on the fault transient zero-sequence current data collected within the set period to obtain transient data, then calculates the amplitude within the set time period after the fault, generates the transient zero-sequence current amplitude sequence of each detection point, and uploads the transient zero-sequence current amplitude sequence to the master station; The master station uses the uploaded transient zero-sequence current amplitude sequence data to calculate the transient zero-sequence current amplitude integral coefficient and amplitude comprehensive difference coefficient of the detection points at both ends of each section on the fault line; The master station performs positioning based on the calculated transient zero-sequence current amplitude integral coefficient and amplitude comprehensive difference coefficient of each section.

2. The single-phase grounding fault location method based on zero-sequence current integration according to claim 1 is characterized in that: Each detection point first performs filtering on the fault transient zero-sequence current data collected within two cycles to obtain transient data.

3. The single-phase grounding fault location method based on zero-sequence current integration according to claim 1 is characterized in that: The amplitudes in the eight time periods after the fault are calculated to generate the transient zero-sequence current amplitude sequence at each detection point.

4. The single-phase grounding fault location method based on zero-sequence current integration according to claim 1 is characterized in that: The master station locates the fault according to the calculated transient zero-sequence current amplitude integral coefficient and amplitude comprehensive difference coefficient of each section. The judgment method is: when the transient zero-sequence current amplitude comprehensive difference coefficient δ is less than the set threshold δset, it is judged that a fault has occurred at the end of the line.

5. The single-phase grounding fault location method based on zero-sequence current integration according to claim 1 is characterized in that: The master station locates the fault according to the calculated transient zero-sequence current amplitude integral coefficient and amplitude comprehensive difference coefficient of each section. The judgment method is: if the transient zero-sequence current amplitude comprehensive difference correlation coefficient is greater than the set threshold δset, the section corresponding to the maximum value of the transient zero-sequence current amplitude integral coefficient is selected as the fault section.

6. The single-phase grounding fault location method based on zero-sequence current integration according to claim 1 is characterized in that: The master station locates according to the calculated transient zero-sequence current amplitude integral coefficient and amplitude comprehensive difference coefficient of each section. The judgment method is: set the threshold δset=0.1, which can be adjusted according to the actual situation on site and the accuracy of the detection equipment.

7. Single-phase ground fault location system based on zero-sequence current integration, characterized in that: include: The data acquisition module is used to record the transient zero-sequence current data of the fault within 0.04s after the fault occurs at each detection point on the line after the single-phase grounding occurs on the line; The data processing module is used for filtering the transient zero-sequence current data collected within the set period at each detection point to obtain transient data, and then calculating the amplitude within the set time period after the fault, generating the transient zero-sequence current amplitude sequence of each detection point, and uploading the transient zero-sequence current amplitude sequence to the main station; A calculation module is used for the master station to calculate the transient zero-sequence current amplitude integral coefficient and the amplitude comprehensive difference coefficient of the detection points at both ends of each section on the fault line using the uploaded transient zero-sequence current amplitude sequence data; The positioning module is used for the master station to perform positioning according to the calculated transient zero-sequence current amplitude integral coefficient and amplitude comprehensive difference coefficient of each section.

8. The single-phase grounding fault location system based on zero-sequence current integration according to claim 7, characterized in that: In the data processing module, each detection point first performs filtering processing on the fault transient zero-sequence current data collected within two cycles to obtain transient data.

9. The single-phase grounding fault location system based on zero-sequence current integration according to claim 7, characterized in that: In the data processing module, the amplitudes in the eight time periods after the fault are calculated to generate the transient zero-sequence current amplitude sequence of each detection point.

10. The single-phase grounding fault location system based on zero-sequence current integration according to claim 7, characterized in that: In the positioning module, the master station performs positioning based on the calculated transient zero-sequence current amplitude integral coefficient and amplitude comprehensive difference coefficient of each section. The judgment method is: when the transient zero-sequence current amplitude comprehensive difference coefficient δ is less than the set threshold δset, it is judged that a fault has occurred at the end of the line.

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