A high-resistance fault detection method and system for a resonant grounding system

Abstract

The present invention discloses a high-resistance fault detection method and system for a resonant grounding system. The method includes: dividing the transient components of the zero-sequence current of each feeder into a first segment, a second segment, and a third segment, selecting the target transient component of the zero-sequence current of the feeder with the largest energy proportion in the first segment, and calculating the energy proportions of the three segments corresponding to the target transient component of the zero-sequence current of the feeder; characterizing the transient initial polarity according to the polarity difference of the transient component projection coefficients in the first segment and constructing a first criterion, 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; respectively setting energy proportion thresholds for the first segment, the second segment, and the third segment, executing the corresponding first criterion, second criterion, and third criterion for different working conditions, and outputting the final fault detection result. By fully utilizing the fault transient characteristic information in different dimensions, the reliability and accuracy of the detection result are improved.

Description

Technical Field

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

[0002] When a single-phase high-impedance fault (HIF) occurs in a resonant grounding distribution system, the detection faces multiple difficulties: the fault current amplitude is small, the signal characteristics are not obvious, and it is difficult to be effectively detected by traditional protection devices; the manifestations of HIF are diverse, such as tree touching the line, broken wire falling to the ground, insulation layer damage, etc., and the current characteristics and time-frequency characteristics of various different faults vary greatly; HIF often shows intermittency and instability, and the intermittent arc discharge phenomenon further increases the complexity of fault detection. At the same time, HIF will threaten personal safety, cause fires, damage equipment, reduce power supply reliability, and lead to a decline in power quality and the 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-impedance fault detection method and system for a resonant grounding system, which is used to solve the technical problems in the prior art that the current amplitude is small, the fault characteristics are weak, and the detection is difficult after a high-impedance grounding fault.

[0004] In a first aspect, the present invention provides a high-impedance fault detection method for a resonant grounding system, including:

[0005] Obtaining the transient components of the zero-sequence current of each feeder and the transient component of the zero-sequence voltage of the bus within a preset time period;

[0006] Dividing the transient components of the zero-sequence current of each feeder into a first segment, a second segment, and a third segment according to a preset window length, selecting the transient component of the zero-sequence current of the target feeder with the largest energy ratio in the first segment, and calculating the energy ratios of the three segments corresponding to the transient component of the zero-sequence current of the target feeder;

[0007] Characterizing the transient initial polarity according to the polarity difference of the transient component projection coefficient in the first segment and constructing a first criterion, 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;

[0008] Setting energy ratio thresholds for the first segment, the second segment, and the third segment respectively, executing the corresponding first criterion, second criterion, and third criterion for different working conditions, and outputting the final fault detection result.

[0009] In a second aspect, the present invention provides a high-impedance fault detection system for a resonant grounding system, including:

[0010] An acquisition module, configured to acquire the transient components of the zero-sequence current of each feeder and the transient component of the zero-sequence voltage of the bus within a preset time period;

[0011] A calculation module, configured to divide the transient components of the 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 transient component of the zero-sequence current of the feeder with the largest energy proportion in the first segment, and calculate the energy proportions of the three segments corresponding to the target transient component of the zero-sequence current of the feeder;

[0012] A construction module, configured to characterize the transient initial polarity according to the polarity difference of the transient component projection coefficients in the first segment and construct a first criterion, 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;

[0013] An output module, configured to set energy proportion thresholds for the first segment, the second segment, and the third segment respectively, execute the corresponding first criterion, second criterion, and third criterion for different working conditions, and output the final fault detection result.

[0014] In a third aspect, an electronic device is provided, which includes: 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 execute the steps of the high-resistance fault detection method for a resonant grounding system according to any embodiment of the present invention.

[0015] In a fourth aspect, the present invention further provides a computer-readable storage medium, on which a computer program is stored, and when the program instructions are executed by a processor, the processor is enabled to execute the steps of the high-resistance fault detection method for a resonant grounding system according to any embodiment of the present invention.

[0016] The high-resistance fault detection method and system for a resonant grounding system of the present application divide the transient components within 3 cycles after a fault into 3 segments, and comprehensively utilize three different dimensional indexes, namely transient initial polarity, transient average energy, and transient similarity, to construct criteria in each segment, which can make full use of the fault transient characteristic information of different dimensions, improve the reliability and accuracy of the detection result, and according to the numerical difference of the energy proportions of different segments, by setting reasonable thresholds and executing different criterion logics, the calculation process of the criteria can be effectively simplified, and the robustness and reliability of the method of the present invention are verified by PSCAD simulation. Description of the Drawings

[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0018] Figure 1 It is a flowchart of a high-resistance fault detection method for a resonant grounding system provided by an embodiment of the present invention;

[0019] Figure 2 It is a schematic diagram of a 10kV resonant grounding system simulation model in the training stage flowchart of an embodiment of the present invention;

[0020] Figure 3 It is a schematic diagram of the transient component waveforms of the zero-sequence current of each feeder within 3 cycles after a fault calculated using the parameters of each line when the simulation model of an embodiment of the present invention has grounding faults of 0.5kΩ, 2kΩ, and 5kΩ respectively;

[0021] Figure 4 It is a schematic diagram of the window length division of the transient component in an embodiment of the present invention;

[0022] Figure 5 It is a schematic diagram of the change range of the energy proportion of the transient components of each of the 3 segments when the value of the transition resistance changes during a single-phase grounding fault in the simulation model of an embodiment of the present invention;

[0023] Figure 6 It is a structural block diagram of a high-resistance fault detection system for a resonant grounding system provided by an embodiment of the present invention;

[0024] Figure 7 It is a schematic diagram of the structure of an electronic device provided by an embodiment of the present invention. Specific embodiments

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

[0026] Please refer to Figure 1 , which shows a flowchart of a high-resistance fault detection method for a resonant grounding system of the present application.

[0027] As Figure 1As shown, the high-resistance fault detection method for a resonant grounding system specifically includes the following steps:

[0028] Step S101, obtain the transient components of the zero-sequence current of each feeder and the transient component of the zero-sequence voltage of the bus within a preset time period.

[0029] In this step, the expressions for the transient components of the zero-sequence current of each feeder and the transient component of the zero-sequence voltage of the bus are:

[0030] ,

[0031] In the formula, is the transient component of the zero-sequence current of the j-th feeder, is the transient component of the zero-sequence voltage of the bus, is the first to the third cycles after the fault of the zero-sequence current of the j-th feeder, is the first to the third cycles before the fault of the zero-sequence current of the j-th feeder, is the 11th to the 13th cycles after the fault of the zero-sequence current of the j-th feeder, is the first to the third cycles after the fault of the zero-sequence voltage of the bus, is the first to the third cycles before the fault of the zero-sequence voltage of the bus, is the 11th to the 13th cycles after the fault of the zero-sequence voltage of the bus.

[0032] Step S102, divide the transient components of the 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 transient component of the zero-sequence current of the feeder with the largest energy ratio in the first segment, and calculate the energy ratios of the three segments corresponding to the target transient component of the zero-sequence current of the feeder.

[0033] In this step, the range of the window length is [0, 1 / 2T], [1 / 2T, 3 / 2T], [3 / 2T, 3T], where 0 represents the fault occurrence time, represents the period;

[0034] The expression for calculating the energy ratio is:

[0035] ,

[0036] In the formula, is the energy ratio of the transient component of the i-th segment, is the total energy of the transient component of the i-th segment;

[0037] ,

[0038] In the formula, is the total number of sampling points of the discrete signal, is the i-th discrete signal.

[0039] Step S103: Characterize the transient initial polarity according to the polarity difference of the transient component projection coefficients within the first segment, construct the first criterion; construct the second criterion according to the transient average energy within the second segment; and construct the third criterion according to the similarity index within the third segment.

[0040] In this step, calculate the projection coefficient of the transient component of the zero-sequence current of each feeder in the first segment on the transient component of the zero-sequence voltage of the bus. The expression is:

[0041] ,

[0042] wherein, is the projection coefficient of the transient component of the zero-sequence current of the j-th feeder in the first segment on the transient component of the zero-sequence voltage of the bus, is the total number of sampling points in the first segment, is the transient component of the zero-sequence current of the j-th feeder in the first segment, is the transient component of the zero-sequence voltage of the bus in the first segment;

[0043] Normalize the obtained values of each projection coefficient. The expression is:

[0044] ,

[0045] wherein, is the projection coefficient of the transient component of the zero-sequence current of the j-th feeder in the first segment on the transient component of the zero-sequence voltage of the bus after normalization, is the value corresponding to the item with the largest absolute value of the projection coefficient;

[0046] Select the item with a positive projection coefficient sign according to the fact that the projection coefficient sign of the faulty feeder is positive and the projection coefficient sign of the healthy feeder is negative. The corresponding feeder is the faulty feeder;

[0047] The construction of the second criterion according to the transient average energy within the second segment includes:

[0048] Normalize the transient components of the zero-sequence current of each feeder respectively. The expression is:

[0049] ,

[0050] wherein, is the value corresponding to the k-th sampling point of the normalized current transient component of the j-th feeder, is the value corresponding to the sampling point with the largest absolute value in the current transient component of the j-th feeder;

[0051] Calculate the transient average energy value corresponding to each feeder within the second segment , and the expression is:

[0052] ,

[0053] wherein, is the value corresponding to the k-th sampling point of the zero-sequence voltage transient component of the busbar in the second subsection, is the number of sampling points in the second subsection;

[0054] Select the feeder corresponding to the item with a transient average energy value greater than 0 and determine it as the faulty feeder;

[0055] Calculate the absolute deviation of each transient average energy value, and select the feeder corresponding to the item with the largest absolute deviation of the transient average energy value as the faulty feeder. Among them, the expression for calculating the absolute deviation of each transient average energy is:

[0056] ,

[0057] wherein, is the absolute deviation of the transient average energy value corresponding to the j-th feeder in the second subsection, is the number of feeders in the second subsection;

[0058] The constructing the third criterion according to the similarity index in the third subsection includes:

[0059] Calculate the RMSE value between the normalized zero-sequence current transient components of each feeder in the third subsection and construct a root mean square error matrix , and the expression is:

[0060] ,

[0061] wherein, is the root mean square error between the normalized current transient components of the first feeder and the -th feeder in the third subsection;

[0062] Calculate the sum of each row of data in the root mean square error matrix to obtain the comprehensive root mean square error of each row corresponding feeder. Finally, select the feeder corresponding to the largest item among them as the faulty feeder.

[0063] Step S104, respectively set the capacity ratio thresholds for the first subsection, the second subsection, and the third subsection, execute the corresponding first criterion, second criterion, and third criterion for different working conditions, and output the final fault detection result.

[0064] In this step, when the energy ratio of the transient component in the first subsection 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 subsection, and directly execute the first criterion for fault detection;

[0065] When the energy ratio of the first segmented transient component ≤66.7% and the energy ratio of the third segmented transient component , compare the energy ratio of the first segmented transient component with the energy ratio of the second segmented transient component ;

[0066] When ≥ , execute the first criterion for fault detection, otherwise execute the second criterion for fault detection;

[0067] When and , comprehensively execute the first criterion, the second criterion and the third criterion for fault detection.

[0068] It should be noted that when and , comprehensively execute the first criterion, the second criterion and the third criterion for fault detection, and determine whether the output results of executing the first criterion, the second criterion and the third criterion are all consistent;

[0069] If they are consistent, directly output the faulty feeder;

[0070] If they are inconsistent, assign correction weights to the results of the first criterion, the second criterion and the third criterion respectively, and perform weighted statistics on the detection results using the weights of the first criterion, the second criterion and the third criterion. The total weight of each line is the sum of the weights of the first criterion, the second criterion and the third criterion that output the results of the corresponding line. Finally, the line with the largest total weight is output as the detection result, and the expression is:

[0071] ,

[0072] In the formula, is the line number, is the weight of the i-th criterion, is the output faulty line result of the i-th criterion. When , , otherwise it is 0.

[0073] In summary, for the method of the present application, the zero-sequence current of each feeder and the transient component of the bus zero-sequence voltage within 3 cycles after a fault are obtained. Secondly, the window lengths of the obtained transient components are divided into 3 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 3 segments of this feeder are calculated. Thirdly, for the transient components of the 3 segments, the first criterion, the second criterion, and the third criterion are sequentially constructed in the corresponding segments. Finally, by setting different thresholds for the energy proportions of the 3 segments, different criterion logics are executed, and the energy proportions of each segment are used to assign correction weights to the criteria of their respective segments, and the line with the largest total weight is output as the final detection result, so as to achieve high-resistance fault detection.

[0074] In a specific embodiment, to intuitively reflect the characteristic differences between the transient components of the faulty feeder and the healthy feeder, a 10 kV resonant grounding system simulation model as shown in Figure 2 is built using PSCAD / EMTDC. This model has a total of 4 feeders, including overhead lines, cable lines, and hybrid lines. The specific feeder parameters are shown in Table 1. This system adopts an over-compensation operation mode, with an over-compensation degree of 8% and an arc suppression coil inductance of 0.8222 H.

[0075] ,

[0076] Assuming single-phase grounding faults of 0.5 kΩ, 2 kΩ, and 5 kΩ occur respectively, the transient component waveforms of the zero-sequence current of each feeder within 3 cycles after the fault are calculated using the parameters of each line as shown in Figure 3 .

[0077] Figure 3 In (a) of , when the transition resistance is 500 Ω, the energy proportion of the transient component of the zero-sequence current of the faulty feeder in the first segment reaches 99%. The first criterion can be constructed using the polarity difference in the first segment to achieve fault detection; Figure 3 In (b) of , when the transition resistance is 2 kΩ, the proportions of the transient components in the first and second segments are 60% and 38% respectively, and the sum of the proportions of the two segments reaches 98%. Moreover, the energy difference between the faulty feeder and the healthy feeder in the second segment is large. At this time, an auxiliary second criterion is constructed using the energy difference in the second segment, and the fault is detected by combining the two criteria; Figure 3 In (c) of , when the transition resistance is 5 kΩ, the proportions of the transient components in the first, second, and third segments are 30%, 43%, and 27% in sequence. At this time, the polarity of the faulty feeder in the first segment and the energy characteristics in the second segment are compared with the conditions in Figure 3 (a) of , Figure 3 (b) of , and gradually approach the healthy feeder. At this time, an auxiliary third criterion is continued to be constructed using the similarity index in the third segment, and the fault is detected by combining the first criterion, the second criterion, and the third criterion, which can further improve the reliability of the detection result.

[0078] When HIF occurs, with the change of the transition resistance, for the same topology and the same feeder, the content of the transient component in the latter half of a half cycle within 3 cycles after the fault varies greatly within the window length. In the prior art, the transient fault detection method mainly uses the signal in the latter half of a half cycle or a shorter signal after the fault to construct the detection criterion, which may not fully utilize the fault transient information, resulting in a decrease in the reliability of the criterion under certain working conditions.

[0079] In response to this, the present invention conducts a segmented analysis on the transient component within 3 cycles after the fault, and divides the transient components with window lengths of 1 / 2T, 1 / 2T - 3 / 2T, and 3 / 2T - 3T after the fault into Figure 4 the 3 segments shown, and constructs different detection logics by calculating the energy ratio of the transient components in different segments and for different working conditions of the energy ratio.

[0080] Figure 5 In [reference], when the transition resistance is 0.5 kΩ, the energy ratio of the first segment is 99.2%, while the energy ratio of the third segment is almost 0, indicating that the transient component is mainly concentrated in the first half cycle after the fault; as the value of the transition resistance increases, the ratio of the first segment gradually decreases to around 20%, while the ratio of the third segment gradually increases to around 42% and is greater than the energy of the first segment; the energy ratio of the second segment will increase rapidly with the increase of the transition resistance and gradually stabilizes at around 38% when it is around 3 kΩ. In summary, by constructing the criterion through segmentation, the fault feature information of different dimensions of the transient component can be fully utilized, and the reliability of the criterion can be enhanced.

[0081] Compared with the prior art, the present invention has the following advantages:

[0082] 1) The transient component within 3 cycles after the fault is divided into 3 segments, and the criterion is constructed by comprehensively using three different - dimension indexes of the transient initial polarity, the transient average energy, and the transient similarity in segments, which can fully utilize the fault transient feature information of different dimensions and improve the reliability and accuracy of the detection result;

[0083] 2) According to the numerical difference of the energy ratio of different segments, by setting reasonable thresholds and executing different criterion logics, the calculation process of the criterion can be effectively simplified, and the robustness and reliability of the method of the present application are verified by PSCAD simulation.

[0084] Please refer to Figure 6 , which shows a structural block diagram of a high - resistance fault detection system for a resonant grounding system according to the present application.

[0085] As Figure 6 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.

[0086] Among them, the acquisition module 210 is configured to acquire the transient components of zero-sequence current of each feeder and the transient component 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 transient component of zero-sequence current of the feeder with the largest energy proportion in the first segment, and calculate the energy proportions of the three segments corresponding to the target transient component of zero-sequence current of the feeder; the construction module 230 is configured to characterize the transient initial polarity according to the polarity difference of the transient component projection coefficient in the first segment and construct a first criterion, 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 respectively set energy proportion thresholds for the first segment, the second segment, and the third segment, execute the corresponding first criterion, second criterion, and third criterion for different working conditions, and output the final fault detection result.

[0087] It should be understood that Figure 6 the modules described in Figure 1 correspond to the respective steps in the method described in Figure 6 Thus, the operations, features, and corresponding technical effects described above for the method also apply to

[0088] In some other embodiments, the embodiments of the present invention further provide a computer-readable storage medium, on which a computer program is stored. 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;

[0089] As an implementation manner, the computer-readable storage medium of the present invention stores computer-executable instructions, and the computer-executable instructions are set as:

[0090] Acquire the transient components of zero-sequence current of each feeder and the transient component of zero-sequence voltage of the bus within a preset time period;

[0091] 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 transient component of zero-sequence current of the feeder with the largest energy proportion in the first segment, and calculate the energy proportions of the three segments corresponding to the target transient component of zero-sequence current of the feeder;

[0092] Characterize the transient initial polarity according to the polarity difference of the transient component projection coefficient in the first segment and construct a first criterion, 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;

[0093] Set the ability ratio thresholds for the first segmented part, the second segmented part, and the third segmented part respectively, execute the corresponding first criterion, second criterion, and third criterion for different working conditions, and output the final fault detection result.

[0094] A computer-readable storage medium may include a storage program area and a storage data area. Among them, the storage program area may store an operating system and application programs required for at least one function; the storage data area may store data created according to the use of the high-resistance fault detection system for resonant grounding systems, etc. In addition, the computer-readable storage medium may include high-speed random access memory, and may also include memory, such as at least one magnetic disk storage device, a flash memory device, or other non-volatile solid-state storage devices. In some embodiments, the computer-readable storage medium may optionally include a memory remotely set relative to the processor, and these remote memories may be connected to the high-resistance fault detection system for resonant grounding systems through a network. Examples of the above network include but are not limited to the Internet, an enterprise intranet, a local area network, a mobile communication network, and combinations thereof.

[0095] Figure 7 is a schematic structural diagram of an electronic device provided by an embodiment of the present invention, as Figure 7 shown, the device includes: a processor 310 and a memory 320. The electronic device may further 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 through a bus or other means, Figure 7 taking the connection through the bus 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 non-volatile software programs, instructions, and modules stored in the memory 320, that is, implements the high-resistance fault detection method for resonant grounding systems in the above method embodiments. The input device 330 may receive input digital or character information, and generate key signal inputs related to user settings and function controls of the high-resistance fault detection system for resonant grounding systems. The output device 340 may include a display device such as a display screen.

[0096] The above electronic device can execute the method provided by the embodiment of the present invention, and has the corresponding functional modules and beneficial effects for executing the method. For technical details not described in detail in this embodiment, reference may be made to the method provided by the embodiment of the present invention.

[0097] As an implementation, the above electronic device is applied to a high-resistance fault detection system and is used for a client, including: 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:

[0098] Obtain the transient components of the zero-sequence current of each feeder and the transient component of the zero-sequence voltage of the bus within a preset time period;

[0099] Divide the transient components of the 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 transient component of the zero-sequence current of the feeder with the largest energy proportion in the first segment, and calculate the energy proportions of the three segments corresponding to the target transient component of the zero-sequence current of the feeder;

[0100] Characterize the transient initial polarity according to the polarity difference of the transient component projection coefficient in the first segment and construct a first criterion, 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;

[0101] Set energy proportion thresholds for the first segment, the second segment, and the third segment respectively, execute the corresponding first criterion, second criterion, and third criterion for different working conditions, and output the final fault detection result.

[0102] Through the description of the above embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus a necessary general hardware platform, and of course, it can also be implemented by hardware. Based on such an understanding, the essence of the above technical solution, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions for causing 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 embodiments.

[0103] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate 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 comprises: 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 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.

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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