Active distribution network adaptive protection method and system based on fault traveling wave

Abstract

The present invention relates to the field of distribution network protection technology, and provides an active distribution network adaptive protection method and system based on fault traveling waves, wherein the method comprises: a distribution terminal collects three-phase current signals of a distribution line in real time, and decouples the three-phase current signals into analog current signals; the effective value of the analog current signal is calculated in each cycle, and if the effective value of the analog current signal exceeds the set limit, it is determined that a fault occurs in the distribution network and the time of exceeding the limit is recorded; the wavelet transform modulus maximum value of the over-limited analog current signal in the cycle before the over-limit moment is calculated, and the position of the traveling wave head is determined by searching for the modulus maximum point; the analog current signal near the traveling wave head position is subjected to high-pass filtering to obtain a high-frequency traveling wave head signal, and the maximum rise rate of the wave head is calculated, and then the minimum rise time is calculated; each distribution terminal dynamically and adaptively adjusts the protection action time based on the minimum rise time calculated by each terminal to complete fault isolation. The present invention can effectively improve the reliability and stability of the distribution network.

Description

Technical Field

[0001] The present invention relates to the technical field of distribution network protection, and in particular to an active distribution network adaptive protection method and system based on fault traveling waves. Background Art

[0002] Distributed photovoltaic and small hydropower projects are constantly advancing, and a large number of distributed power sources are connected to the distribution network, which has transformed the distribution network from the traditional single-end power supply mode to a multi-end power supply network. In particular, long-span overhead lines with a large power supply radius have the characteristics of multiple sections and long branch lines. As overhead lines are exposed to the natural environment for a long time, the probability of failure is greatly increased.

[0003] When a short-circuit fault occurs in the active distribution network, due to the presence of distributed power sources, the short-circuit current is provided by the two-terminal power supply after the fault. Therefore, when a short-circuit fault occurs in the adjacent feeder or the upstream line of the distributed power source grid connection point, the distributed power source will provide short-circuit current to the fault point. This will cause the traditional three-stage current protection used in the single-power radial distribution network to malfunction. In addition, the access and low voltage ride-through capability of the distributed power source increase the voltage at the grid connection point, which has an external draw or boost effect on the short-circuit current, thereby reducing the sensitivity of the three-stage current protection, and may also cause refusal or malfunction. Summary of the invention

[0004] The purpose of the present invention is to solve at least one technical problem in the background technology and to provide an active distribution network adaptive protection method and system based on fault traveling waves.

[0005] To achieve the above object, the present invention provides an active distribution network adaptive protection method based on fault traveling waves, comprising:

[0006] The distribution terminals in the active distribution network collect the three-phase current signals of the distribution lines in real time, and decouple the three-phase current signals into analog current signals through phase-to-analog conversion;

[0007] The effective value of the analog current signal is calculated every cycle. If the effective value of the analog current signal exceeds the set limit, it is considered that the distribution network has a fault and the time of exceeding the limit is recorded;

[0008] Calculate the wavelet transform modulus maximum of the over-limit modulus current signal in a cycle before the over-limit moment, and determine the position of the traveling wave head by searching for the modulus maximum point;

[0009] Perform high-pass filtering on the mode current signal near the traveling wave head position to obtain the high-frequency traveling wave head signal, calculate the maximum rise rate of the wave head, and then calculate the minimum rise time;

[0010] Each distribution terminal dynamically and adaptively adjusts the protection action time based on its own calculated minimum rise time to complete fault isolation.

[0011] According to one aspect of the present invention, decoupling the three-phase current signal into the analog current signal is: converting the three-phase current into the analog current by matrix multiplication:

[0012] [ i 0 i 1 i 2 ] = [ 1 1 1 1 − 1 0 1 0 − 1 ] [ i a i b i c ]

[0013] where i a 、i b 、i c is the three-phase current sampling value, i 0 、i 1 、i 2 is the mode current after decoupling, i 1 、i 2 is the line mode current, i 0 is zero mode current.

[0014] According to one aspect of the present invention, the distribution network fault includes a phase-to-phase fault and a ground fault, the phase-to-phase fault is monitored by line mode current, and the ground fault is monitored by zero mode current;

[0015] The effective value of the analog current signal is calculated in each cycle. If the effective value of the analog current signal exceeds the set limit, it is determined that a fault occurs in the distribution network and the time of exceeding the limit is recorded as:

[0016]

[0017] where x i ,y i 、z i The mode current i 0 、i 1 、i 2 The sampling values ​​are equally spaced within a cycle, and the number of sampling points is N, I set-l ,I set-z are the fault thresholds of line mode current and zero mode current respectively, || represents logical OR; for each distribution terminal in the active distribution network, I set-l and I set-z The setting value is the same.

[0018] According to one aspect of the present invention, the method for determining the position of the traveling wave head is:

[0019] Select the sampling data of the over-limit mode current signal in the cycle before the over-limit moment, perform wavelet transform on the sampling data and extract the high-frequency coefficients of the wavelet transform, calculate the modulus value of the high-frequency coefficient and find the first modulus maximum point, the original sampling data point corresponding to the first modulus maximum point is the traveling wave head position.

[0020] According to one aspect of the present invention, the minimum rise time is calculated as follows:

[0021] Perform high-pass filtering on the adjacent data on both sides of the determined traveling wave head position to obtain the high-frequency traveling wave head signal h 1 ,h 2 ,h 3 ,…,h N , calculate the slope ki between adjacent high-frequency traveling wave head signals:

[0022] , where h i and h i+1 is the high-frequency traveling wave head signal, i=1, 2, 3…, N;

[0023] Calculate the slope change modulus D i :

[0024]

[0025] Search Make D i Take the maximum value of data point i, denoted as i dp , high-frequency traveling wave head mode maximum M p for:

[0026]

[0027] Calculate the maximum slope k of the sampling data before the maximum position of the high-frequency traveling wave head mode max :

[0028]

[0029] Calculate the minimum rise time t min :

[0030] .

[0031] According to one aspect of the present invention, the adaptive adjustment protection action time t trip The calculation method is:

[0032]

[0033] where k adj For the adjustment coefficient, the default value can be 1.

[0034] To achieve the above object, the present invention also provides an active distribution network adaptive protection system based on fault traveling waves, which is characterized by comprising:

[0035] The analog current signal decoupling module, the distribution terminal in the active distribution network collects the three-phase current signal of the distribution line in real time, and decouples the three-phase current signal into the analog current signal through phase-to-analog conversion;

[0036] The fault identification module calculates the effective value of the analog current signal every cycle. If the effective value of the analog current signal exceeds the set limit, it is determined that a fault has occurred in the distribution network and the time of exceeding the limit is recorded;

[0037] The traveling wave head position determination module calculates the wavelet transform modulus maximum of the over-limit modulus current signal in a cycle before the over-limit moment, and determines the traveling wave head position by searching for the modulus maximum point;

[0038] The minimum rise time calculation module performs high-pass filtering on the mode current signal near the traveling wave head position to obtain the high-frequency traveling wave head signal, calculates the maximum rise rate of the wave head, and then calculates the minimum rise time;

[0039] In the fault isolation module, each distribution terminal dynamically and adaptively adjusts the protection action time based on its own calculated minimum rise time to complete fault isolation.

[0040] To achieve the above-mentioned purpose, the present invention also provides an electronic device, including a processor, a memory, and a computer program stored in the memory and executable on the processor, wherein when the computer program is executed by the processor, the active distribution network adaptive protection method based on fault traveling waves as described above is implemented.

[0041] To achieve the above objectives, the present invention also provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the active distribution network adaptive protection method based on fault traveling waves as described above is implemented.

[0042] According to the solution of the present invention, the distribution terminals in the active distribution network can adaptively adapt to the access and operation of distributed power sources, adaptively adjust the action time according to different fault locations, and ensure that the switches adjacent to the fault location take priority to isolate the fault, thereby reducing the workload and difficulty of manual adjustment, and eliminating the need for external communication system support, thereby improving the reliability and stability of the distribution network. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 A flowchart schematically showing an active distribution network adaptive protection method based on fault traveling waves according to an embodiment of the present invention;

[0044] Figure 2 A schematic diagram of an active power distribution network fault simulation diagram according to Embodiment 1 of the present invention is shown;

[0045] Figure 3 A diagram schematically showing the corresponding relationship between the wavelet transform modulus maximum and the traveling wave head position according to Embodiment 1 of the present invention;

[0046] Figure 4 The figure schematically shows a high-frequency traveling wave head signal diagram according to the embodiment 1 of the present invention. DETAILED DESCRIPTION

[0047] The present invention will now be discussed with reference to exemplary embodiments. It should be understood that the embodiments discussed are only to enable those skilled in the art to better understand and thus implement the present invention, rather than implying any limitation on the scope of the present invention.

[0048] As used herein, the term “including” and variations thereof are to be interpreted as open-ended terms meaning “including, but not limited to.” The term “based on” is to be interpreted as “based, at least in part, on.” The terms “one embodiment” and “an embodiment” are to be interpreted as “at least one embodiment.”

[0049] Figure 1 The flowchart of the active distribution network adaptive protection method based on fault traveling wave according to one embodiment of the present invention is schematically shown. Figure 1 As shown, in this embodiment, the active distribution network adaptive protection method based on fault traveling wave includes:

[0050] The distribution terminals in the active distribution network collect the three-phase current signals of the distribution lines in real time, and decouple the three-phase current signals into analog current signals through phase-to-analog conversion;

[0051] The effective value of the analog current signal is calculated every cycle. If the effective value of the analog current signal exceeds the set limit, it is considered that the distribution network has a fault and the time of exceeding the limit is recorded;

[0052] Calculate the wavelet transform modulus maximum of the over-limit modulus current signal in a cycle before the over-limit moment, and determine the position of the traveling wave head by searching for the modulus maximum point;

[0053] Perform high-pass filtering on the mode current signal near the traveling wave head position to obtain the high-frequency traveling wave head signal, calculate the maximum rise rate of the wave head, and then calculate the minimum rise time;

[0054] Each distribution terminal dynamically and adaptively adjusts the protection action time based on its own calculated minimum rise time to complete fault isolation.

[0055] Further, according to an embodiment of the present invention, decoupling the three-phase current signal into the analog current signal is as follows: converting the three-phase current into the analog current by matrix multiplication:

[0056] [ i 0 i 1 i 2 ] = [ 1 1 1 1 − 1 0 1 0 − 1 ] [ i a i b i c ]

[0057] where i a 、i b 、i c is the three-phase current sampling value, i 0 、i 1 、i2 is the mode current after decoupling, i 1 、i 2 is the line mode current, i 0 is zero mode current.

[0058] Further, according to an embodiment of the present invention, the distribution network fault includes a phase-to-phase fault and a ground fault, the phase-to-phase fault is monitored by line mode current, and the ground fault is monitored by zero mode current;

[0059] The effective value of the analog current signal is calculated in each cycle. If the effective value of the analog current signal exceeds the set limit, it is determined that a fault occurs in the distribution network and the time of exceeding the limit is recorded as:

[0060]

[0061] where x i ,y i 、z i The mode current i 0 、i 1 、i 2 The sampling values ​​are equally spaced within a cycle, and the number of sampling points is N, I set-l ,I set-z are the fault thresholds of line mode current and zero mode current respectively, || represents logical OR; for each distribution terminal in the active distribution network, I set-l and I set-z The setting value is the same.

[0062] Further, according to an embodiment of the present invention, the method for determining the position of the traveling wave head is:

[0063] Select the sampling data of the over-limit mode current signal in the cycle before the over-limit moment, perform wavelet transform on the sampling data and extract the high-frequency coefficients of the wavelet transform, calculate the modulus value of the high-frequency coefficient and find the first modulus maximum point, the original sampling data point corresponding to the first modulus maximum point is the traveling wave head position.

[0064] Further, according to an embodiment of the present invention, the calculation method of the minimum rise time is:

[0065] Perform high-pass filtering on the adjacent data on both sides of the determined traveling wave head position to obtain the high-frequency traveling wave head signal h 1 ,h 2 ,h 3 ,…,h N , calculate the slope ki between adjacent high-frequency traveling wave head signals:

[0066] , where h i and h i+1 is the high-frequency traveling wave head signal, i=1, 2, 3…, N;

[0067] Calculate the slope change modulus D i :

[0068]

[0069] Search Make D i Take the maximum value of data point i, denoted as i dp , high-frequency traveling wave head mode maximum M p for:

[0070]

[0071] Calculate the maximum slope k of the sampling data before the maximum position of the high-frequency traveling wave head mode max :

[0072]

[0073] Calculate the minimum rise time t min :

[0074] .

[0075] Further, according to an embodiment of the present invention, the protection action time t is adaptively adjusted. trip The calculation method is:

[0076]

[0077] where k adj For the adjustment coefficient, the default value can be 1.

[0078] According to the above scheme of the present invention, the distribution terminals in the active distribution network can adaptively adapt to the access and operation of distributed power sources, adaptively adjust the action time according to different fault locations, and ensure that the switches adjacent to the fault location take priority to isolate the fault, thereby reducing the workload and difficulty of manual adjustment, and eliminating the need for external communication system support, thereby improving the reliability and stability of the distribution network.

[0079] Furthermore, in order to achieve the above-mentioned object, the present invention also provides an active distribution network adaptive protection system based on fault traveling waves, comprising:

[0080] The analog current signal decoupling module, the distribution terminal in the active distribution network collects the three-phase current signal of the distribution line in real time, and decouples the three-phase current signal into the analog current signal through phase-to-analog conversion;

[0081] The fault identification module calculates the effective value of the analog current signal every cycle. If the effective value of the analog current signal exceeds the set limit, it is determined that a fault has occurred in the distribution network and the time of exceeding the limit is recorded;

[0082] The traveling wave head position determination module calculates the wavelet transform modulus maximum of the over-limit modulus current signal in a cycle before the over-limit moment, and determines the traveling wave head position by searching for the modulus maximum point;

[0083] The minimum rise time calculation module performs high-pass filtering on the mode current signal near the traveling wave head position to obtain the high-frequency traveling wave head signal, calculates the maximum rise rate of the wave head, and then calculates the minimum rise time;

[0084] In the fault isolation module, each distribution terminal dynamically and adaptively adjusts the protection action time based on its own calculated minimum rise time to complete fault isolation.

[0085] Further, according to an embodiment of the present invention, decoupling the three-phase current signal into the analog current signal is as follows: converting the three-phase current into the analog current by matrix multiplication:

[0086] [ i 0 i 1 i 2 ] = [ 1 1 1 1 − 1 0 1 0 − 1 ] [ i a i b i c ]

[0087] where i a 、i b 、i c is the three-phase current sampling value, i 0 、i 1 、i 2 is the mode current after decoupling, i 1 、i 2 is the line mode current, i 0 is zero mode current.

[0088] Further, according to an embodiment of the present invention, the distribution network fault includes a phase-to-phase fault and a ground fault, the phase-to-phase fault is monitored by line mode current, and the ground fault is monitored by zero mode current;

[0089] The effective value of the analog current signal is calculated in each cycle. If the effective value of the analog current signal exceeds the set limit, it is determined that a fault occurs in the distribution network and the time of exceeding the limit is recorded as:

[0090]

[0091] where x i ,y i 、z i The mode current i 0 、i 1 、i 2 The sampling values ​​are equally spaced within a cycle, and the number of sampling points is N, I set-l ,I set-z are the fault thresholds of line mode current and zero mode current respectively, || represents logical OR; for each distribution terminal in the active distribution network, I set-l and I set-z The setting value is the same.

[0092] Further, according to an embodiment of the present invention, the method for determining the position of the traveling wave head is:

[0093] Select the sampling data of the over-limit mode current signal in the cycle before the over-limit moment, perform wavelet transform on the sampling data and extract the high-frequency coefficients of the wavelet transform, calculate the modulus value of the high-frequency coefficient and find the first modulus maximum point, the original sampling data point corresponding to the first modulus maximum point is the traveling wave head position.

[0094] Further, according to an embodiment of the present invention, the minimum rise time is calculated as follows:

[0095] Perform high-pass filtering on the adjacent data on both sides of the determined traveling wave head position to obtain the high-frequency traveling wave head signal h 1 ,h 2 ,h 3 ,…,h N , calculate the slope ki between adjacent high-frequency traveling wave head signals:

[0096] , where h i and h i+1 is the high-frequency traveling wave head signal, i=1, 2, 3…, N;

[0097] Calculate the slope change modulus D i :

[0098]

[0099] Search Make D i Take the maximum value of data point i, denoted as i dp , high-frequency traveling wave head mode maximum M p for:

[0100]

[0101] Calculate the maximum slope k of the sampling data before the maximum position of the high-frequency traveling wave head mode max :

[0102]

[0103] Calculate the minimum rise time t min :

[0104] .

[0105] Further, according to an embodiment of the present invention, the protection action time t is adaptively adjusted. trip The calculation method is:

[0106]

[0107] where k adj For the adjustment coefficient, the default value can be 1.

[0108] According to the above scheme of the present invention, the distribution terminals in the active distribution network can adaptively adapt to the access and operation of distributed power sources, adaptively adjust the action time according to different fault locations, and ensure that the switches adjacent to the fault location take priority to isolate the fault, thereby reducing the workload and difficulty of manual adjustment, and eliminating the need for external communication system support, thereby improving the reliability and stability of the distribution network.

[0109] Furthermore, to achieve the above-mentioned purpose, the present invention also provides an electronic device, including a processor, a memory, and a computer program stored in the memory and executable on the processor, wherein when the computer program is executed by the processor, the active distribution network adaptive protection method based on fault traveling waves as described above is implemented.

[0110] Furthermore, to achieve the above-mentioned purpose, the present invention also provides a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the active distribution network adaptive protection method based on fault traveling waves as described above is implemented.

[0111] Based on the above solution of the present invention, the solution of the present invention is described in detail in the following in combination with the accompanying drawings in the form of a specific embodiment.

[0112] Example 1

[0113] Figure 2 For the overhead line diagram of the distribution network, Figure 2 As shown in the figure, the line between K1 and K2 is 5 km long, the line between K2 and K3 is 4 km long, a small hydropower station is connected between K2 and K3, and the fault occurs 2 km after K3. The fault type is a metallic short circuit fault of AB phases. The line mode current fault threshold value I of the distribution terminal of K1, K2, and K3 switches set-l All are set to 500A (primary value).

[0114] Before the fault, the distribution terminals of K1, K2, and K3 switches collect the three-phase current signals of the distribution line at a sampling rate of 2MHz, decouple the three-phase current signals into analog current signals through phase-to-analog conversion, and calculate the effective value of the analog current signal, where i 1 (K1) =169A, i 1 (K2) = 48A, i 1 (K3) = 145A.

[0115] After the fault occurs, the effective value of the line mode current increases, where i 1 (K1) = 2100A, i 1(K2) = 2083A, i 1 (K3) = 2579A, the effective value of the line mode current signal of each distribution terminal exceeds the set limit I set-l = 500A, trigger the calculation of the wavelet transform modulus maximum of the cycle before the limit crossing moment, and determine the position of the traveling wave head by searching for the modulus maximum point. Taking the K2 switch as an example, the corresponding relationship between the wavelet transform modulus maximum 1 in the wavelet transform modulus data and the traveling wave head position 2 in the original sampling data is as follows: Figure 3 shown.

[0116] Furthermore, the mode current signal near the traveling wave head position is high-pass filtered. Taking the K2 switch as an example, the high-frequency traveling wave head signal after filtering is as follows: Figure 4 As shown. K1, K2, K3 switches each calculate the minimum rise time, t min (K1) = 2.094, t min (K2)=1.761, t min (K3) = 1.401.

[0117] Finally, each distribution terminal calculates the protection action time based on its own calculated minimum rise time, t trip (K1) = 0.321, t trip (K2)=0.246, t trip (K3)= 0.147, the K3 switch adjacent to the fault location takes precedence to isolate the fault.

[0118] Those skilled in the art will appreciate that the modules and algorithm steps described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

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

[0120] In the embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the modules is only a logical function division. There may be other division methods in actual implementation, such as multiple modules or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or modules, which can be electrical, mechanical or other forms.

[0121] The modules described as separate components may or may not be physically separated, and the components shown as modules may or may not be physical modules, that is, they may be located in one place or distributed on multiple network modules. Some or all of the modules may be selected according to actual needs to achieve the purpose of the embodiments of the present invention.

[0122] In addition, each functional module in the embodiment of the present invention may be integrated into one processing module, or each module may exist physically separately, or two or more modules may be integrated into one module.

[0123] If the functions are implemented in the form of software function modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention can be essentially or partly embodied in the form of a software product that contributes to the prior art. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to perform all or part of the steps of the energy-saving signal sending / receiving method of each embodiment of the present invention. The aforementioned storage medium includes: various media that can store program codes, such as USB flash drives, mobile hard disks, ROM, RAM, magnetic disks, or optical disks.

[0124] The above description is only a preferred embodiment of the present application and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the invention involved in the present application is not limited to the technical solution formed by a specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the above features are replaced with the technical features with similar functions disclosed in this application (but not limited to) by each other.

[0125] It should be understood that the size of the serial numbers of each step in the content of the invention and the implementation methods of the present invention does not absolutely mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the implementation methods of the present invention.

Claims

1. An adaptive protection method for active distribution network based on fault traveling waves, characterized in that: include: The distribution terminals in the active distribution network collect the three-phase current signals of the distribution lines in real time, and decouple the three-phase current signals into analog current signals through phase-to-analog conversion; The effective value of the analog current signal is calculated every cycle. If the effective value of the analog current signal exceeds the set limit, it is considered that the distribution network has a fault and the time of exceeding the limit is recorded; Calculate the wavelet transform modulus maximum of the over-limit modulus current signal in a cycle before the over-limit moment, and determine the position of the traveling wave head by searching for the modulus maximum point; Perform high-pass filtering on the mode current signal near the traveling wave head position to obtain the high-frequency traveling wave head signal, calculate the maximum rise rate of the wave head, and then calculate the minimum rise time; Each distribution terminal dynamically and adaptively adjusts the protection action time based on its own calculated minimum rise time to complete fault isolation; The minimum rise time is calculated as follows: The data near both sides of the determined traveling wave head position are high-pass filtered to obtain high-frequency traveling wave head signals h1, h2, h3, ..., h N , calculate the slope ki between adjacent high-frequency traveling wave head signals: , where h i and h i+1 is the high-frequency traveling wave head signal, i=1, 2, 3…, N; Calculate the slope change modulus D i : ； Search Make D i Take the maximum value of data point i, denoted as i dp , high-frequency traveling wave head mode maximum M p for: ； Calculate the maximum slope k of the sampling data before the maximum position of the high-frequency traveling wave head mode max： ； Calculate the minimum rise time t min： ； The adaptive adjustment protection action time t trip The calculation method is: ； where k adj It is the adjustment coefficient, and the default value is 1.

2. The method for adaptive protection of active distribution network based on fault traveling wave according to claim 1, characterized in that: The decoupling of the three-phase current signal into the analog current signal is as follows: the three-phase current is converted into the analog current by matrix multiplication: ； where i a 、i b 、i c are the three-phase current sampling values, i0, i1, i2 are the mode currents after decoupling, i1 and i2 are the line mode currents, and i0 is the zero mode current.

3. The method for adaptive protection of active distribution network based on fault traveling wave according to claim 2, characterized in that: Distribution network faults include phase-to-phase faults and ground faults. Phase-to-phase faults are monitored by line-mode current, and ground faults are monitored by zero-mode current. The effective value of the analog current signal is calculated in each cycle. If the effective value of the analog current signal exceeds the set limit, it is determined that a fault occurs in the distribution network and the time of exceeding the limit is recorded as: ； where x i ,y i 、z i are the equally spaced sampling values ​​of the mode currents i0, i1, and i2 in one cycle, and the number of sampling points is N, I set-l ,I set-z are the fault thresholds of line mode current and zero mode current respectively, || represents logical OR; for each distribution terminal in the active distribution network, I set-l and I set-z The setting value is the same.

4. The method for adaptive protection of active distribution network based on fault traveling wave according to claim 1, characterized in that: The method for determining the position of the traveling wave head is: Select the sampling data of the over-limit mode current signal in the cycle before the over-limit moment, perform wavelet transform on the sampling data and extract the high-frequency coefficients of the wavelet transform, calculate the modulus value of the high-frequency coefficient and find the first modulus maximum point, the original sampling data point corresponding to the first modulus maximum point is the traveling wave head position.

5. Active distribution network adaptive protection system based on fault traveling wave, characterized in that: include: The analog current signal decoupling module, the distribution terminal in the active distribution network collects the three-phase current signal of the distribution line in real time, and decouples the three-phase current signal into the analog current signal through phase-to-analog conversion; The fault identification module calculates the effective value of the analog current signal every cycle. If the effective value of the analog current signal exceeds the set limit, it is determined that a fault has occurred in the distribution network and the time of exceeding the limit is recorded; The traveling wave head position determination module calculates the wavelet transform modulus maximum of the over-limit modulus current signal in a cycle before the over-limit moment, and determines the traveling wave head position by searching for the modulus maximum point; The minimum rise time calculation module performs high-pass filtering on the mode current signal near the traveling wave head position to obtain the high-frequency traveling wave head signal, calculates the maximum rise rate of the wave head, and then calculates the minimum rise time; Fault isolation module: each distribution terminal dynamically and adaptively adjusts the protection action time based on its own calculated minimum rise time to complete fault isolation; The calculation method of the minimum rise time is: The data near both sides of the determined traveling wave head position are high-pass filtered to obtain high-frequency traveling wave head signals h1, h2, h3, ..., h N , calculate the slope ki between adjacent high-frequency traveling wave head signals: , where h i and h i+1 is the high-frequency traveling wave head signal, i=1, 2, 3…, N; Calculate the slope change modulus D i： ； Search Make D i Take the maximum value of data point i, denoted as i dp , high-frequency traveling wave head mode maximum M p for: ； Calculate the maximum slope k of the sampling data before the maximum position of the high-frequency traveling wave head mode max： ； Calculate the minimum rise time t min： ； The adaptive adjustment protection action time t trip The calculation method is: ； where k adj It is the adjustment coefficient, and the default value is 1.

6. An electronic device, characterized in that The invention comprises a processor, a memory and a computer program stored in the memory and executable on the processor, wherein when the computer program is executed by the processor, the method for adaptive protection of an active distribution network based on fault traveling waves as described in any one of claims 1 to 4 is implemented.

7. A computer-readable storage medium, characterized in that The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the method for adaptive protection of an active distribution network based on fault traveling waves according to any one of claims 1 to 4 is implemented.

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