High-resistance fault detection method and system for resonant grounding system

Abstract

The invention discloses a high-resistance fault detection method and system for a resonant grounding system, and the method comprises the steps: dividing a zero-sequence current transient component of each feeder line into a first segment, a second segment and a third segment, selecting a zero-sequence current transient component of a target feeder line with the maximum energy ratio in the first segment, and selecting a zero-sequence current transient component of the target feeder line with the maximum energy ratio in the third segment; calculating the energy ratio of three segments corresponding to the transient component of the zero-sequence current of the target feeder; in the first segment, according to the transient component projection coefficient polarity difference, representing the transient initial polarity and constructing a first criterion, in the second segment, according to the transient average energy, constructing a second criterion, and in the third segment, according to the similarity index, constructing a third criterion; and respectively setting capability ratio thresholds for the first segment, the second segment and the third segment, executing a corresponding first criterion, a second criterion and a third criterion for different working conditions, and outputting a final fault detection result. And fault transient characteristic information of different dimensions is fully utilized, and the reliability and accuracy of a detection result are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of relay protection of power system distribution network, and in particular relates to a high-resistance fault detection method and system for a resonant grounding system. Background Art

[0002] When a single-phase high-impedance fault (HIF) occurs in a resonantly connected local distribution system, detection faces multiple difficulties: the fault current amplitude is small and the signal characteristics are not obvious, making it difficult to be effectively detected by traditional protection devices; HIFs manifest in various forms, such as trees touching the wires, broken wires falling to the ground, insulation damage, etc., and the current characteristics and time-frequency characteristics of various faults vary greatly; HIFs often manifest as intermittent and unstable, and intermittent arc discharges further increase the complexity of fault detection. At the same time, HIFs can threaten personal safety, cause fires, damage equipment, reduce power supply reliability, and lead to a decline in power quality and failure of protection devices. Therefore, it is urgent to study accurate and reliable high-impedance fault detection methods. Summary of the invention

[0003] The present invention provides a high-resistance fault detection method and system for a resonant grounding system, which are used to solve the technical problems in the prior art that the current amplitude after a high-resistance grounding fault is small, the fault characteristics are weak, and the detection is difficult.

[0004] In a first aspect, the present invention provides a high-resistance fault detection method for a resonant grounding system, comprising: Obtaining the transient components of zero-sequence current of each feeder and zero-sequence voltage of the bus within a preset time period; Divide each feeder zero-sequence current transient component into a first segment, a second segment, and a third segment according to a preset window length, select the target feeder zero-sequence current transient component with the largest energy proportion in the first segment, and calculate the energy proportions of the three segments corresponding to the target feeder zero-sequence current transient component; In the first segment, the transient initial polarity is characterized according to the polarity difference of the transient component projection coefficient and a first criterion is constructed; in the second segment, a second criterion is constructed according to the transient average energy; and in the third segment, a third criterion is constructed according to the similarity index; Capacity ratio thresholds are set for the first segment, the second segment, and the third segment respectively, corresponding first criteria, second criteria, and third criteria are executed for different working conditions, and a final fault detection result is output.

[0005] In a second aspect, the present invention provides a high-resistance fault detection system for a resonant grounding system, comprising: An acquisition module configured to acquire transient components of zero-sequence current of each feeder and transient components of zero-sequence voltage of the busbar within a preset time period; A calculation module is configured to divide each feeder zero-sequence current transient component into a first segment, a second segment, and a third segment according to a preset window length, select a target feeder zero-sequence current transient component with the largest energy proportion in the first segment, and calculate energy proportions of three segments corresponding to the target feeder zero-sequence current transient component; A construction module, configured to characterize the transient initial polarity and construct a first criterion according to the polarity difference of the transient component projection coefficient in the first segment, construct a second criterion according to the transient average energy in the second segment, and construct a third criterion according to the similarity index in the third segment; The output module is configured to set capacity ratio thresholds for the first segment, the second segment and the third segment respectively, execute the corresponding first criterion, the second criterion and the third criterion for different working conditions, and output the final fault detection result.

[0006] According to a third aspect, an electronic device is provided, comprising: at least one processor, and a memory communicatively connected to the at least one processor, wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can perform the steps of the high-resistance fault detection method for a resonant grounding system according to any embodiment of the present invention.

[0007] In a fourth aspect, the present invention further provides a computer-readable storage medium having a computer program stored thereon, wherein when the program instructions are executed by a processor, the processor executes the steps of the high-resistance fault detection method for a resonant grounding system of any embodiment of the present invention.

[0008] The high-resistance fault detection method and system for a resonant grounding system of the present application divides the transient components within three cycles after the fault into three segments, and constructs a criterion by comprehensively utilizing three different dimensional indicators, namely, transient initial polarity, transient average energy, and transient similarity. This can make full use of the transient characteristic information of faults in different dimensions to improve the reliability and accuracy of the detection results. Moreover, according to the numerical differences in the energy proportions of different segments, by setting reasonable thresholds and executing different criterion logics, the calculation process of the criterion can be effectively simplified. The robustness and reliability of the method of the present invention have been verified through PSCAD simulation. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0010] Figure 1A flow chart of a high-resistance fault detection method for a resonant grounding system provided by an embodiment of the present invention; Figure 2 A flowchart of the training phase of an embodiment of the present invention is a schematic diagram of a 10kV resonant grounding system simulation model; Figure 3 A schematic diagram of the transient component waveform of zero-sequence current of each feeder within three cycles after the fault is obtained by using various line parameters when 0.5kΩ, 2kΩ, and 5kΩ ground faults occur in the simulation model of an embodiment of the present invention respectively; Figure 4 A schematic diagram of transient component window length division according to an embodiment of the present invention; Figure 5 A schematic diagram of the change range of the transient component energy proportion of each of the three segments when a single-phase grounding fault occurs in a simulation model of an embodiment of the present invention and the value of the transition resistance changes; Figure 6 A structural block diagram of a high-resistance fault detection system for a resonant grounding system provided by an embodiment of the present invention; Figure 7 It is a schematic diagram of the structure of an electronic device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0011] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0012] See also Figure 1 , which shows a flow chart of a high-resistance fault detection method for a resonant grounding system of the present application.

[0013] like Figure 1 As shown, the high-resistance fault detection method for a resonant grounding system specifically includes the following steps: Step S101, obtaining the transient components of zero-sequence current of each feeder and the transient components of zero-sequence voltage of the bus within a preset time period.

[0014] In this step, the expressions of the transient components of zero-sequence current of each feeder and the transient components of zero-sequence voltage of the bus are: , In the formula, is the transient component of zero-sequence current of the jth feeder, is the transient component of bus zero-sequence voltage, is the first to third cycle after the zero-sequence current fault of the jth feeder, is the first to third cycles before the zero-sequence current fault of the jth feeder, is the 11th to 13th cycle after the zero-sequence current fault of the jth feeder, It is the 1st to 3rd cycle after the bus zero-sequence voltage fault. It is the first to third cycle before the bus zero-sequence voltage fault. It is the 11th to 13th cycle after the bus zero-sequence voltage fault.

[0015] Step S102, divide each feeder zero-sequence current transient component into a first segment, a second segment and a third segment according to a preset window length, select the target feeder zero-sequence current transient component with the largest energy proportion in the first segment, and calculate the energy proportions of the three segments corresponding to the target feeder zero-sequence current transient component.

[0016] In this step, the window length ranges from [0, 1 / 2T], [1 / 2T, 3 / 2T], [3 / 2T, 3T], where 0 represents the time when the fault occurs. Indicates a cycle; The expression for calculating the energy ratio is: , In the formula, is the energy proportion of the transient component of the i-th segment, is the total energy of the transient component of the i-th segment; , In the formula, is the total number of sampling points of the discrete signal, is the ith discrete signal.

[0017] Step S103, characterizing the transient initial polarity and constructing a first criterion according to the polarity difference of the transient component projection coefficient in the first segment, constructing a second criterion according to the transient average energy in the second segment, and constructing a third criterion according to the similarity index in the third segment.

[0018] In this step, the projection coefficient of the zero-sequence current transient component of each feeder in the first segment to the zero-sequence voltage transient component of the bus is calculated, and the expression is: , In the formula, is the projection coefficient of the zero-sequence current transient component of the j-th feeder in the first segment on the zero-sequence voltage transient component of the busbar, is the total number of sampling points in the first segment, is the transient component of zero-sequence current of the jth feeder in the first segment, is the transient component of the zero-sequence voltage of the busbar in the first section; The obtained projection coefficients are normalized and the expression is: , In the formula, is the projection coefficient of the zero-sequence current transient component of the j-th feeder in the first segment on the zero-sequence voltage transient component of the busbar after normalization, It is the value corresponding to the item with the largest absolute value of the projection coefficient; According to the projection coefficient sign of the faulty feeder is positive, and the projection coefficient sign of the sound feeder is negative, select the one with a positive projection coefficient sign, and the corresponding feeder is the faulty feeder; The second criterion constructed according to the transient average energy in the second segment includes: The transient components of zero-sequence current of each feeder are normalized respectively, and the expression is: , In the formula, is the value corresponding to the kth sampling point of the normalized current transient component of the jth feeder, is the value corresponding to the sampling point with the largest absolute value in the transient component of the j-th feeder current; Calculate the transient average energy value corresponding to each feeder in the second segment , the expression is: , In the formula, is the value corresponding to the kth sampling point of the transient component of the bus zero-sequence voltage in the second segment, is the number of sampling points of the second segment; Select the feeder corresponding to the item with transient average energy value greater than 0 and determine it as the faulty feeder; The absolute deviation of each transient average energy value is calculated, and the feeder corresponding to the item with the largest absolute deviation of the transient average energy value is selected as the fault feeder. The expression for calculating the absolute deviation of each transient average energy is: , In the formula, is the absolute deviation of the transient average energy value corresponding to the jth feeder in the second segment, is the number of feeders in the second segment; The constructing of the third criterion according to the similarity index in the third segment includes: Calculate the RMSE value between the normalized zero-sequence current transient components of each feeder in the third segment and construct the root mean square error matrix , the expression is: , In the formula, For the first feeder and the The RMS error between the normalized current transient components of the feeders in the third segment; Calculate the root mean square error matrix The sum of each row of data is the comprehensive RMS error of the feeder corresponding to each row. Finally, the feeder corresponding to the largest item is selected as the faulty feeder.

[0019] Step S104, respectively setting capacity ratio thresholds for the first segment, the second segment and the third segment, executing corresponding first criterion, second criterion and third criterion for different working conditions, and outputting a final fault detection result.

[0020] In this step, when the energy proportion of the transient component of the first segment When the proportion is greater than 2 / 3 of the total energy of the window length, that is, , at this time, the transient component is concentrated in the first segment, and the first criterion is directly executed for fault detection; When the energy proportion of the transient component in the first segment ≤66.7% and the energy proportion of the third segment transient component When comparing the energy proportion of the transient component of the first segment The energy ratio of the transient component in the second segment ; when ≥ When the fault occurs, the first criterion is executed to perform fault detection, otherwise the second criterion is executed to perform fault detection; when and When the fault occurs, the first criterion, the second criterion and the third criterion are comprehensively executed to perform fault detection.

[0021] It should be noted that when and When the fault is detected, the first criterion, the second criterion and the third criterion are comprehensively executed, and it is determined whether the output results of the first criterion, the second criterion and the third criterion are consistent; If they are consistent, the fault feeder is directly output; If they are inconsistent, the results of the first criterion, the second criterion and the third criterion are respectively given modified weights, and the weights of the first criterion, the second criterion and the third criterion are used to perform weighted statistics on the detection results. The total weight of each line is the sum of the weights of the corresponding line results output in the first criterion, the second criterion and the third criterion. Finally, the line with the largest total weight is selected. As the detection result output, the expression is: , In the formula, is the line number, is the weight of the ith criterion, is the output fault line result of the i-th criterion, when hour, , otherwise 0.

[0022] In summary, the method of the present application obtains the transient components of the zero-sequence current of each feeder and the zero-sequence voltage of the bus within three cycles after the fault. Secondly, the window lengths of each transient component obtained are divided into three segments according to [0, 1 / 2T], [1 / 2T, 3 / 2T], and [3 / 2T, 3T]. The feeder with the largest energy proportion in the first segment is selected and the energy proportions of the three segments of the feeder are calculated. Thirdly, for the transient components of the three segments, the first criterion, the second criterion, and the third criterion are constructed in the corresponding segments in turn. Finally, different thresholds are set for the energy proportions of the three segments, different criterion logics are executed, and the energy proportions of each segment are used to assign corrected weights to the criteria of each segment, and the line with the largest total weight is output as the final detection result, thereby realizing high-resistance fault detection.

[0023] In a specific embodiment, in order to intuitively reflect the characteristic difference between the transient components of the faulty feeder and the healthy feeder, PSCAD / EMTDC is used to build the following Figure 2 The simulation model of the 10kV resonant grounding system is shown in Figure 1. The model has 4 feeders, including overhead lines, cable lines and mixed lines. The specific feeder parameters are shown in Table 1. The system adopts overcompensation operation mode, the overcompensation degree is 8%, and the arc suppression coil inductance is 0.8222H.

[0024] , Assuming that 0.5kΩ, 2kΩ and 5kΩ single-phase grounding faults occur respectively, the line parameters are used to calculate Figure 3 The transient component waveforms of zero-sequence current of each feeder within three cycles after the fault are shown.

[0025] Figure 3 In (a), when the transition resistance is 500Ω, the energy proportion of the transient component of the zero-sequence current of the faulty feeder in the first segment reaches 99%, and the first criterion can be constructed in the first segment using the polarity difference to realize fault detection; Figure 3 In (b), when the transition resistance is 2 kΩ, the proportion of transient components in the first and second segments is 60% and 38% respectively, and the sum of the proportions of the two segments reaches 98%. In addition, the energy difference between the faulty feeder and the healthy feeder in the second segment is large. At this time, the energy difference is used to construct the auxiliary second criterion in the second segment, and the two criteria are combined to achieve fault detection. Figure 3 In (c), the transition resistance is 5kΩ, and the transient component accounts for 30%, 43% and 27% in the first, second and third segments respectively. At this time, the polarity characteristics of the fault feeder in the first segment and the energy characteristics in the second segment are compared with the working condition. Figure 3 (a) Figure 3 (b) in the figure gradually approaches the healthy feeder. At this time, the similarity index is continued to be used in the third segment to construct the auxiliary third criterion, and the first criterion, the second criterion, and the third criterion are combined for fault detection, which can further improve the reliability of the detection result.

[0026] When HIF occurs, as the transition resistance changes, for the same topology and the same feeder, the transient component content in the half-cycle window length after the fault within 3 cycles is quite different. However, the transient fault detection method in the prior art mainly uses the half-cycle or shorter signal after the fault to construct the detection criterion, which may not fully utilize the fault transient information, resulting in reduced reliability of the criterion under certain working conditions.

[0027] In this regard, the present invention performs segmented analysis on the transient components of the three cycles after the fault, and divides the transient components of the 1 / 2T, 1 / 2T~3 / 2T and 3 / 2T~3T window lengths after the fault into Figure 4 The three segments shown are calculated by calculating the energy proportion of transient components in different segments and constructing different detection logics for different working conditions with different energy proportions.

[0028] Figure 5 In the figure, when the transition resistance is 0.5kΩ, the energy proportion of the first segment is 99.2%, while the energy proportion of the third segment is almost 0, indicating that the transient component is mainly concentrated in the first 1 / 2 cycle after the fault; and as the transition resistance value increases, the proportion of the first segment gradually decreases to around 20%, while the proportion of the third segment gradually increases to about 42%, and is greater than the energy of the first segment; the energy proportion of the second segment will increase rapidly with the increase of the transition resistance, and gradually stabilize at around 3kΩ, maintaining at around 38%. In summary, by constructing the criterion in a segmented manner, we can make full use of the fault feature information of different dimensions of the transient component and enhance the reliability of the criterion.

[0029] Compared with the prior art, the present invention has the following advantages: 1) The transient components within three cycles after the fault are divided into three sections, and the three different dimensional indicators of transient initial polarity, transient average energy and transient similarity are comprehensively used to construct the judgment criteria, which can make full use of the transient characteristic information of faults in different dimensions and improve the reliability and accuracy of the detection results; 2) According to the numerical differences in the energy proportions of different segments, by setting reasonable thresholds and executing different judgment logics, the calculation process of the judgment can be effectively simplified, and the robustness and reliability of the proposed method are verified through PSCAD simulation.

[0030] See also Figure 6 , which shows a structural block diagram of a high-resistance fault detection system for a resonant grounding system of the present application.

[0031] like Figure 6 As shown, the high-resistance fault detection system 200 includes an acquisition module 210 , a calculation module 220 , a construction module 230 and an output module 240 .

[0032] Among them, the acquisition module 210 is configured to obtain the transient components of zero-sequence current of each feeder and the transient components of zero-sequence voltage of the bus within a preset time period; the calculation module 220 is configured to divide the transient components of zero-sequence current of each feeder into a first segment, a second segment and a third segment according to a preset window length, select the target feeder zero-sequence current transient component with the largest energy proportion in the first segment, and calculate the energy proportion of the three segments corresponding to the target feeder zero-sequence current transient component; the construction module 230 is configured to characterize the initial polarity of the transient and construct a first criterion according to the polarity difference of the transient component projection coefficient in the first segment, construct a second criterion according to the transient average energy in the second segment, and construct a third criterion according to the similarity index in the third segment; the output module 240 is configured to set capacity proportion thresholds for the first segment, the second segment and the third segment respectively, execute the corresponding first criterion, the second criterion and the third criterion for different working conditions, and output the final fault detection result.

[0033] It should be understood that Figure 6 Modules and references documented in Figure 1 Therefore, the operations and features described above for the method and the corresponding technical effects are also applicable to Figure 6 The modules in it will not be described in detail here.

[0034] In some other embodiments, the embodiments of the present invention further provide a computer-readable storage medium having a computer program stored thereon, wherein when the program instructions are executed by a processor, the processor is caused to execute the high-resistance fault detection method for a resonant grounding system in any of the above method embodiments; As an implementation mode, the computer-readable storage medium of the present invention stores computer-executable instructions, and the computer-executable instructions are configured as follows: Obtaining the transient components of zero-sequence current of each feeder and zero-sequence voltage of the bus within a preset time period; Divide each feeder zero-sequence current transient component into a first segment, a second segment, and a third segment according to a preset window length, select the target feeder zero-sequence current transient component with the largest energy proportion in the first segment, and calculate the energy proportions of the three segments corresponding to the target feeder zero-sequence current transient component; In the first segment, the transient initial polarity is characterized according to the polarity difference of the transient component projection coefficient and a first criterion is constructed; in the second segment, a second criterion is constructed according to the transient average energy; and in the third segment, a third criterion is constructed according to the similarity index; Capacity ratio thresholds are set for the first segment, the second segment, and the third segment respectively, corresponding first criteria, second criteria, and third criteria are executed for different working conditions, and a final fault detection result is output.

[0035] The computer-readable storage medium may include a program storage area and a data storage area, wherein the program storage area may store an operating system and an application required by at least one function; the data storage area may store data created according to the use of the high-resistance fault detection system for a resonant grounding system, etc. In addition, the computer-readable storage medium may include a high-speed random access memory, and may also include a memory, such as at least one disk storage device, a flash memory device, or other non-volatile solid-state storage device. In some embodiments, the computer-readable storage medium may optionally include a memory remotely arranged relative to the processor, and these remote memories may be connected to the high-resistance fault detection system for a resonant grounding system via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0036] Figure 7 is a schematic diagram of the structure of an electronic device provided by an embodiment of the present invention, such as Figure 7 As shown, the device includes: a processor 310 and a memory 320. The electronic device may also include: an input device 330 and an output device 340. The processor 310, the memory 320, the input device 330 and the output device 340 may be connected via a bus or other means. Figure 7 In the example, the connection through the bus is taken as an example. The memory 320 is the above-mentioned computer-readable storage medium. The processor 310 executes various functional applications and data processing of the server by running the non-volatile software programs, instructions and modules stored in the memory 320, that is, the high-resistance fault detection method for the resonant grounding system of the above-mentioned method embodiment is implemented. The input device 330 can receive input digital or character information, and generate key signal input related to user settings and function control of the high-resistance fault detection system for the resonant grounding system. The output device 340 may include a display device such as a display screen.

[0037] The electronic device can execute the method provided by the embodiment of the present invention, and has the functional modules and beneficial effects corresponding to the execution method. For technical details not described in detail in this embodiment, please refer to the method provided by the embodiment of the present invention.

[0038] As an implementation mode, the electronic device is applied to a high-resistance fault detection system and is used for a client, and includes: at least one processor; and a memory connected to the at least one processor in communication; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can: Obtaining the transient components of zero-sequence current of each feeder and zero-sequence voltage of the bus within a preset time period; Divide each feeder zero-sequence current transient component into a first segment, a second segment, and a third segment according to a preset window length, select the target feeder zero-sequence current transient component with the largest energy proportion in the first segment, and calculate the energy proportions of the three segments corresponding to the target feeder zero-sequence current transient component; In the first segment, the transient initial polarity is characterized according to the polarity difference of the transient component projection coefficient and a first criterion is constructed; in the second segment, a second criterion is constructed according to the transient average energy; and in the third segment, a third criterion is constructed according to the similarity index; Capacity ratio thresholds are set for the first segment, the second segment, and the third segment respectively, corresponding first criteria, second criteria, and third criteria are executed for different working conditions, and a final fault detection result is output.

[0039] Through the description of the above implementation modes, those skilled in the art can clearly understand that each implementation mode can be implemented by means of software plus a necessary general hardware platform, or of course by hardware. Based on such an understanding, the above technical solution can essentially or in other words be embodied in the form of a software product that contributes to the prior art. The computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a magnetic disk, an optical disk, etc., and includes a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods of each embodiment or some parts of the embodiment.

[0040] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention 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 invention.

Claims

1. A high-resistance fault detection method for a resonant grounding system, characterized in that: include: Obtaining the transient components of zero-sequence current of each feeder and zero-sequence voltage of the bus within a preset time period; Divide each feeder zero-sequence current transient component into a first segment, a second segment, and a third segment according to a preset window length, select the target feeder zero-sequence current transient component with the largest energy proportion in the first segment, and calculate the energy proportions of the three segments corresponding to the target feeder zero-sequence current transient component; In the first segment, the transient initial polarity is characterized according to the polarity difference of the transient component projection coefficient and a first criterion is constructed; in the second segment, a second criterion is constructed according to the transient average energy; and in the third segment, a third criterion is constructed according to the similarity index; Capacity ratio thresholds are set for the first segment, the second segment, and the third segment respectively, corresponding first criteria, second criteria, and third criteria are executed for different working conditions, and a final fault detection result is output.

2. A high-resistance fault detection method for a resonant grounding system according to claim 1, characterized in that: in, The expressions of the transient components of zero-sequence current of each feeder and the transient components of zero-sequence voltage of the bus are: ， In the formula, is the transient component of zero-sequence current of the jth feeder, is the transient component of bus zero-sequence voltage, is the first to third cycle after the zero-sequence current fault of the jth feeder, is the first to third cycles before the zero-sequence current fault of the jth feeder, is the 11th to 13th cycle after the zero-sequence current fault of the jth feeder, It is the 1st to 3rd cycle after the bus zero-sequence voltage fault. It is the first to third cycle before the bus zero-sequence voltage fault. It is the 11th to 13th cycle after the bus zero-sequence voltage fault.

3. A high-resistance fault detection method for a resonant grounding system according to claim 1, characterized in that: The range of the window length is [0, 1 / 2T], [1 / 2T, 3 / 2T], [3 / 2T, 3T], where 0 represents the time when the fault occurs. Indicates a cycle; The expression for calculating the energy ratio is: ， In the formula, is the energy proportion of the transient component of the i-th segment, is the total energy of the transient component of the i-th segment; ， In the formula, is the total number of sampling points of the discrete signal, is the ith discrete signal.

4. A high-resistance fault detection method for a resonant grounding system according to claim 1, characterized in that: in, The characterizing the transient initial polarity and constructing the first criterion according to the polarity difference of the transient component projection coefficient in the first segment includes: Calculate the projection coefficient of the zero-sequence current transient component of each feeder in the first segment to the zero-sequence voltage transient component of the busbar. The expression is: ， In the formula, is the projection coefficient of the zero-sequence current transient component of the j-th feeder in the first segment on the zero-sequence voltage transient component of the busbar, is the total number of sampling points in the first segment, is the transient component of zero-sequence current of the jth feeder in the first segment, is the transient component of the zero-sequence voltage of the busbar in the first section; The obtained projection coefficients are normalized and the expression is: ， In the formula, is the projection coefficient of the zero-sequence current transient component of the j-th feeder in the first segment on the zero-sequence voltage transient component of the busbar after normalization, It is the value corresponding to the item with the largest absolute value of the projection coefficient; According to the projection coefficient sign of the faulty feeder is positive, and the projection coefficient sign of the sound feeder is negative, select the one with a positive projection coefficient sign, and the corresponding feeder is the faulty feeder; The second criterion constructed according to the transient average energy in the second segment includes: The transient components of zero-sequence current of each feeder are normalized respectively, and the expression is: ， In the formula, is the value corresponding to the kth sampling point of the normalized current transient component of the jth feeder, is the value corresponding to the sampling point with the largest absolute value in the transient component of the j-th feeder current; Calculate the transient average energy value corresponding to each feeder in the second segment , the expression is: ， In the formula, is the value corresponding to the kth sampling point of the transient component of the bus zero-sequence voltage in the second segment, is the number of sampling points of the second segment; Select the feeder corresponding to the item with transient average energy value greater than 0 and determine it as the faulty feeder; The absolute deviation of each transient average energy value is calculated, and the feeder corresponding to the item with the largest absolute deviation of the transient average energy value is selected as the fault feeder. The expression for calculating the absolute deviation of each transient average energy is: ， In the formula, is the absolute deviation of the transient average energy value corresponding to the jth feeder in the second segment, is the number of feeders in the second segment; The constructing of the third criterion according to the similarity index in the third segment includes: Calculate the RMSE value between the normalized zero-sequence current transient components of each feeder in the third segment and construct the root mean square error matrix , the expression is: ， In the formula, For the first feeder and the The RMS error between the normalized current transient components of the feeders in the third segment; Calculate the root mean square error matrix The sum of each row of data is the comprehensive RMS error of the feeder corresponding to each row. Finally, the feeder corresponding to the largest item is selected as the faulty feeder.

5. A high-resistance fault detection method for a resonant grounding system according to claim 1, characterized in that: The executing of the corresponding first criterion, the second criterion and the third criterion according to different working conditions and outputting the final fault detection result includes: When the energy proportion of the transient component in the first segment When the proportion is greater than 2 / 3 of the total energy of the window length, that is, , at this time, the transient component is concentrated in the first segment, and the first criterion is directly executed for fault detection; When the energy proportion of the transient component in the first segment ≤66.7% and the energy proportion of the third segment transient component When comparing the energy proportion of the transient component of the first segment The energy ratio of the second segment transient component ; when ≥ When the fault occurs, the first criterion is executed to perform fault detection, otherwise the second criterion is executed to perform fault detection; when and When the fault occurs, the first criterion, the second criterion and the third criterion are comprehensively executed to perform fault detection.

6. A high-resistance fault detection method for a resonant grounding system according to claim 5, characterized in that: When and When the first criterion, the second criterion and the third criterion are comprehensively executed to perform fault detection, including: when and When the fault is detected, the first criterion, the second criterion and the third criterion are comprehensively executed, and it is determined whether the output results of the first criterion, the second criterion and the third criterion are consistent; If they are consistent, the fault feeder is directly output; If they are inconsistent, the results of the first criterion, the second criterion and the third criterion are respectively given modified weights, and the weights of the first criterion, the second criterion and the third criterion are used to perform weighted statistics on the detection results. The total weight of each line is the sum of the weights of the corresponding line results output in the first criterion, the second criterion and the third criterion. Finally, the line with the largest total weight is selected. As the detection result output, the expression is: ， In the formula, is the line number, is the weight of the ith criterion, is the output fault line result of the i-th criterion, when hour, , otherwise 0.

7. A high-resistance fault detection system for a resonant grounding system, characterized in that: include: An acquisition module configured to acquire transient components of zero-sequence current of each feeder and transient components of zero-sequence voltage of the busbar within a preset time period; A calculation module is configured to divide each feeder zero-sequence current transient component into a first segment, a second segment, and a third segment according to a preset window length, select a target feeder zero-sequence current transient component with the largest energy proportion in the first segment, and calculate energy proportions of three segments corresponding to the target feeder zero-sequence current transient component; A construction module, configured to characterize the transient initial polarity and construct a first criterion according to the polarity difference of the transient component projection coefficient in the first segment, construct a second criterion according to the transient average energy in the second segment, and construct a third criterion according to the similarity index in the third segment; The output module is configured to set capacity ratio thresholds for the first segment, the second segment and the third segment respectively, execute the corresponding first criterion, the second criterion and the third criterion for different working conditions, and output the final fault detection result.

8. An electronic device, characterized in that: include: At least one processor, and a memory communicatively connected to the at least one processor, wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to perform the method described in any one of claims 1 to 6.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the method according to any one of claims 1 to 6 is implemented.

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