Direct-current power distribution network fault detection method based on high-frequency voltage on boundary line side of magnetic ring and related device

Abstract

The invention provides a direct-current power distribution network fault detection method based on high-frequency voltage of a magnetic ring boundary line side and a related device. The method comprises the following steps: responding to a fault starting criterion of a direct-current power distribution network system to be detected; if the system is disturbed, judging whether the fault direction is a positive direction fault by using the post-fault transient power polarity, if not, judging the fault direction is a negative direction fault, and if so, calculating a 1-mode voltage fault component according to the positive and negative voltage of the magnetic ring line side; calculating a time-frequency distribution matrix obtained by performing Stockwel transformation on the component; performing synchronous extrusion transformation on the matrix to obtain time-frequency distribution after energy redistribution; and calculating the sum of module values of the high-frequency fault components of the 1-mode voltage and judging internal and external faults, if the sum of the module values is not less than a set value, judging the internal faults as internal faults, otherwise, judging the internal faults as positive external faults. On the basis of the magnetic ring boundary element and the synchronous extrusion Stockwell transformation, an internal and external fault identification criterion is provided, and the cost can be effectively reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of fault detection of a DC distribution network, and in particular relates to a DC distribution network fault detection method and related devices based on high-frequency voltage on the line side of a magnetic ring boundary. Background Art

[0002] As new power systems continue to evolve toward higher efficiency, greater intelligence, and lower carbon emissions, DC distribution networks, as a key link between renewable energy, energy storage systems, and DC loads, have become a core component of the future Energy Internet. Compared to traditional AC distribution networks, they offer significant advantages in reducing line losses and flexibly adjusting power. They play a crucial role in facilitating the integration of intermittent renewable energy sources like photovoltaic and wind power, and in accommodating the clustering of DC loads, such as data centers and electric vehicle charging facilities.

[0003] Lines are the elements with the highest probability of failure in power systems. Line protection methods primarily include dual-terminal / multi-terminal protection and single-terminal protection. Dual-terminal / multi-terminal protection utilizes dual-terminal or multi-terminal information to identify fault locations, such as directional longitudinal protection and current differential protection. However, when applied on a large scale in DC distribution networks, the large number of distribution lines, flexible and changeable topologies, and complex communication channel configurations lead to high costs. Single-terminal protection utilizes only local information for fault identification and is a more cost-effective solution, particularly boundary protection. By combining protection on one side of the line with boundary elements on the other side, it is possible to identify faults across the entire line using a single-terminal electrical quantity. Currently, there are proposals for flexible DC distribution network fault protection methods based on improved current-limiting reactance voltage using empirical wavelet transforms.

[0004] Existing technologies propose low-voltage DC distribution network protection methods based on power electronic transformer fault ride-through strategies. However, these methods are unable to distinguish between end-of-line faults and faults on the next-level line. These methods are only applicable in scenarios where no further outgoing lines are present at the end of the line. For multi-level line scenarios, three-stage current protection is required to identify the fault location. Another existing technology proposes protection criteria for identifying in-zone and out-of-zone faults using a kurtosis algorithm based on the boundary characteristics of current-limiting reactors. However, this method requires current-limiting reactors at both ends of the line. In the case of a DC distribution network with a large number of outgoing converters, configuring current-limiting reactors on both sides of the line is not only costly, but also difficult to implement due to the reactors being directly connected to the line. Summary of the Invention

[0005] In view of this, the present invention provides a DC distribution network fault detection method and related devices based on the high-frequency voltage on the line side of the magnetic ring boundary. The method aims to extract the high-frequency voltage component based on the synchronous squeezed Stockwel transform, and proposes a criterion for identifying in-zone and out-of-zone faults under the action of the magnetic ring boundary element, thereby reducing the cost of the existing method and realizing effective identification of full-line faults based on single-ended electrical quantities.

[0006] In order to achieve the above object, the technical solution provided by the present invention is as follows:

[0007] In a first aspect, the present invention provides a method for detecting faults in a DC distribution network based on high-frequency voltage on the line side of a magnetic ring boundary, comprising the following steps:

[0008] responding to a fault start criterion of the DC distribution network system to be detected; the fault start criterion is used to determine whether a disturbance occurs in the DC distribution network system;

[0009] If the system is disturbed, the transient power polarity after the fault is used to determine whether the fault direction is a forward fault. If not, the system fault is determined to be a reverse fault. If so, proceed to the subsequent steps.

[0010] Calculate the 1-mode voltage fault component based on the positive and negative voltages on the magnetic ring line side;

[0011] Calculate the Stockwel transform of the 1-mode voltage fault component to obtain the time-frequency distribution matrix of the 1-mode voltage fault component;

[0012] Perform synchronous squeezing transformation on the time-frequency distribution matrix to obtain the time-frequency distribution of the 1-mode voltage fault component after energy redistribution;

[0013] Based on the time-frequency distribution of the 1-mode voltage fault component, the sum of the modulus values ​​of the 1-mode voltage high-frequency fault component is calculated;

[0014] The internal and external faults are judged based on the sum of the modulus values ​​of the high-frequency fault components of the 1-mode voltage. If the sum of the modulus values ​​is not less than the set value, the system fault is judged to be an internal fault. If the sum of the modulus values ​​is less than the set value, the system fault is judged to be a positive external fault.

[0015] Furthermore, the fault start criteria are as follows:

[0016]

[0017] Where, and They represent the calculated value of the positive voltage startup criterion and the calculated value of the negative voltage startup criterion respectively. Indicates the setting value of the start criterion;

[0018] The calculation formula for the voltage starting criterion calculation value of the positive and negative electrodes is as follows:

[0019]

[0020] Where, and Indicates the positive and negative voltages on the magnetic ring line side. represents the sampling interval, Indicates the current calculation time index, Indicates the number of sampling points in the data window, Indicates the sampling point index within the data window.

[0021] Furthermore, the fault initiation criterion in response to the DC power distribution network system to be detected includes:

[0022] Collect the voltage on the magnetic ring line side and calculate the voltage start criterion value;

[0023] Based on the voltage start criterion calculation value, it is determined whether the fault start criterion is met. If so, it is determined that a disturbance occurs in the system.

[0024] Furthermore, the 1-mode voltage fault component is calculated based on the positive and negative voltages on the magnetic ring line side, including:

[0025] The voltage of the positive and negative electrodes is used to calculate the 1-mode voltage as follows:

[0026]

[0027] Where, Indicates 1-mode voltage, and Indicates the positive and negative voltages on the line side of the magnetic ring;

[0028] The 1-mode voltage fault component is calculated using the 1-mode voltage as follows:

[0029]

[0030] Where, Indicates the 1-mode voltage fault component, Indicates the 1-mode voltage in the data window before the fault. express The average value of .

[0031] Furthermore, the time-frequency distribution matrix of the 1-mode voltage fault component is calculated as follows:

[0032]

[0033] Where, represents the time-frequency distribution matrix of the 1-mode voltage fault component, Indicates the time point index, represents the sampling interval, Indicates the number of sampling points in the data window, Indicates the sampling point index, represents the frequency index, It represents the 1-mode voltage fault component, and i represents the imaginary unit.

[0034] Furthermore, the time-frequency distribution of the 1-mode voltage fault component after energy redistribution is determined according to the following formula:

[0035]

[0036] Where, represents the time-frequency distribution of the 1-mode voltage fault component after energy redistribution, represents the time variable, represents the frequency variable of the synchronized squeezed S transform, represents discrete frequency values, represents the length of the kth frequency interval, represents the instantaneous frequency matrix, represents the frequency interval, Indicates the frequency Half the frequency interval at Represents the time-frequency distribution matrix of the 1-mode voltage fault component.

[0037] Furthermore, the sum of the modulus values ​​of the high-frequency fault components of the 1-mode voltage is determined according to the following formula:

[0038]

[0039] Where, represents the sum of the modulus values ​​of the high-frequency fault components of the 1-mode voltage, represents the frequency variable of the synchronized squeezed S transform, Indicates the effective frequency band range of the boundary, represents the time variable, Indicates the data window length, It represents the time-frequency distribution of the 1-mode voltage fault component after energy redistribution.

[0040] In a second aspect, the present invention provides a DC distribution network fault detection device based on high-frequency voltage on the line side of a magnetic ring boundary, comprising:

[0041] A startup judgment module is used to respond to a fault startup judgment criterion of the DC distribution network system to be detected; the fault startup judgment criterion is used to determine whether a disturbance occurs in the DC distribution network system;

[0042] The first fault judgment module is used to judge whether the fault direction is a forward fault by using the transient power polarity after the fault when the system is disturbed. If not, the system fault is judged to be a reverse fault. If so, proceed to the subsequent steps;

[0043] The first calculation module is used to calculate the 1st mode voltage fault component according to the positive and negative voltages on the magnetic ring line side;

[0044] The second calculation module is used to calculate the Stockwel transform of the 1-mode voltage fault component to obtain the time-frequency distribution matrix of the 1-mode voltage fault component;

[0045] The third calculation module is used to perform synchronous squeezing transformation on the time-frequency distribution matrix to obtain the time-frequency distribution of the 1-mode voltage fault component after energy redistribution;

[0046] A fourth calculation module is used to calculate the sum of the module values ​​of the high-frequency fault component of the 1-mode voltage based on the time-frequency distribution of the 1-mode voltage fault component;

[0047] The second fault judgment module judges the internal and external faults based on the sum of the module values ​​of the high-frequency fault components of the 1st module voltage. If the sum of the module values ​​is not less than the set value, the system fault is judged to be an internal fault. If the sum of the module values ​​is less than the set value, the system fault is judged to be a forward external fault.

[0048] In a third aspect, the present invention provides a computer device, comprising a processor and a memory:

[0049] The memory is used to store computer programs and send instructions of the computer programs to the processor;

[0050] The processor executes the DC distribution network fault detection method based on the high-frequency voltage on the line side of the magnetic ring boundary according to the instructions of the computer program as described in the first aspect.

[0051] In a fourth aspect, the present invention provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, a DC distribution network fault detection method based on high-frequency voltage on the magnetic ring boundary line side as in the first aspect is implemented.

[0052] In summary, the present invention provides a DC distribution network fault detection method and related devices based on the high-frequency voltage on the side of a magnetic ring boundary line, including a fault start-up criterion responsive to a DC distribution network system to be detected; the fault start-up criterion is used to determine whether a disturbance occurs in the DC distribution network system; if a disturbance occurs in the system, the transient power polarity after the fault is used to determine whether the fault direction is a forward fault, if not, the system fault is determined to be a reverse fault, and if so, the subsequent steps are continued; a 1-mode voltage fault component is calculated based on the positive and negative voltages on the magnetic ring line side; a Stockwel transform of the 1-mode voltage fault component is calculated to obtain a time-frequency distribution matrix of the 1-mode voltage fault component; a synchronous squeezing transform is performed on the time-frequency distribution matrix to obtain a time-frequency distribution of the 1-mode voltage fault component after energy redistribution; based on the time-frequency distribution of the 1-mode voltage fault component, the sum of the modulus values ​​of the 1-mode voltage high-frequency fault component is calculated; and internal and external faults are determined based on the sum of the modulus values ​​of the 1-mode voltage high-frequency fault component. If the sum of the modulus values ​​is not less than a set value, the system fault is determined to be an internal fault, and if the sum of the modulus values ​​is less than the set value, the system fault is determined to be a forward external fault. The present invention proposes a criterion for identifying faults inside and outside the zone based on magnetic ring boundary elements and synchronous extrusion Stockwell transformation. This eliminates the need for high-cost and difficult-to-implement current-limiting reactors on both sides, effectively reducing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0054] Figure 1 A flow chart of a DC distribution network fault detection method based on high-frequency voltage on the line side of a magnetic ring boundary provided by an embodiment of the present invention;

[0055] Figure 2 A block diagram of a DC distribution network fault detection device based on high-frequency voltage on the line side of a magnetic ring boundary provided by an embodiment of the present invention;

[0056] Figure 3 A block diagram of a computer device provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0057] In order to make the purposes, features, and advantages of the present invention more obvious and easy to understand, the technical solutions 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 embodiments described below are only 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 making creative work are within the scope of protection of the present invention.

[0058] An embodiment of the present invention provides a method for detecting faults in a DC distribution network based on high-frequency voltage on the line side of a magnetic ring boundary, comprising the following steps:

[0059] S1: responding to a fault start criterion of the DC distribution network system to be detected; the fault start criterion is used to determine whether a disturbance occurs in the DC distribution network system.

[0060] It should be noted that the fault start criterion is a condition used to determine whether a disturbance occurs in the DC distribution network system.

[0061] This step monitors relevant electrical quantities in the DC distribution network in real time. When these quantities meet pre-set fault trigger criteria, it is assumed that a system fault or disturbance has occurred, initiating the subsequent fault detection process. For example, a system disturbance can be determined based on voltage or current mutation exceeding a certain threshold.

[0062] S2: If the system is disturbed, the transient power polarity after the fault is used to determine whether the fault direction is a forward fault. If not, the system fault is determined to be a reverse fault. If so, continue with the subsequent steps.

[0063] It's important to note that transient power refers to the change in power in a circuit during the transient state following a fault. Power polarity refers to the direction of power flow. A forward fault typically occurs when the fault point is located on a specific forward side of the protection installation, while a reverse fault is the opposite.

[0064] After a fault occurs, transient power is generated in the DC distribution network. The polarity of the transient power is calculated using the power calculation formula and the measured voltage and current data. If the transient power polarity matches the characteristics of a forward fault, the fault is considered forward and subsequent detection steps proceed. If not, the fault is considered reverse, and appropriate measures can be taken or portions of the detection process terminated as needed.

[0065] S3: Calculate the 1-mode voltage fault component based on the positive and negative voltages on the magnetic ring line side.

[0066] It should be noted that the 1-mode voltage fault component is a voltage component obtained by performing operations such as phase-mode transformation on the positive and negative voltages on the magnetic ring line side.

[0067] This step uses the phase-mode transformation formula to convert the positive and negative voltages measured on the magnetic ring line side into a modulus form, from which the 1st mode voltage fault component is extracted.

[0068] S4: Calculate the Stockwel transform of the 1-mode voltage fault component to obtain the time-frequency distribution matrix of the 1-mode voltage fault component.

[0069] It should be noted that the Stockwell transform (S transform) is a time-frequency analysis method that combines the advantages of short-time Fourier transform and wavelet transform. It is suitable for analyzing non-stationary signals and can convert time domain signals into time-frequency domain representation to obtain a time-frequency distribution matrix.

[0070] Based on the definition and formula of the Stockwell transform, the 1-mode voltage fault component obtained in step S3 is calculated. By selecting appropriate window functions and parameters, the 1-mode voltage fault component is expanded in both time and frequency dimensions to obtain its energy distribution at different times and frequencies, which is expressed as a time-frequency distribution matrix.

[0071] S5: Perform synchronous squeezing transformation on the time-frequency distribution matrix to obtain the time-frequency distribution of the 1-mode voltage fault component after energy redistribution.

[0072] It should be noted that the synchronous squeezing transform is a method for optimizing the time-frequency distribution. It can redistribute the energy in the time-frequency distribution, make the time-frequency representation more concentrated, and improve the time-frequency resolution.

[0073] This step applies the synchronous squeezing transform algorithm to the time-frequency distribution matrix obtained in step S4. This algorithm repositions and squeezes the frequency components in the time-frequency distribution, concentrating the energy of the same signal component, which was originally dispersed at different frequency points, near its true frequency. This results in a time-frequency distribution of the 1-mode voltage fault component after energy redistribution, more clearly displaying the time-frequency characteristics of the fault signal.

[0074] S6: Based on the time-frequency distribution of the 1-mode voltage fault component, calculate the sum of the modulus values ​​of the 1-mode voltage high-frequency fault component.

[0075] It should be noted that the sum of the moduli refers to the sum of the moduli of the high-frequency fault component of the voltage modulus 1 within a certain frequency range. The high-frequency fault component here refers to the portion corresponding to the high-frequency band in the time-frequency distribution. The range of the high-frequency band can be set according to actual conditions.

[0076] This step determines the range of the high-frequency segment based on the time-frequency distribution after energy redistribution obtained in step S5. The modulus values ​​of the 1-mode voltage fault component within this range are then extracted and summed to obtain the sum of the modulus values ​​of the 1-mode voltage high-frequency fault component. This sum of the modulus values ​​reflects the magnitude of the high-frequency fault energy.

[0077] S7: Determine whether the fault is inside or outside the zone based on the sum of the modulus values ​​of the high-frequency fault component of the 1-mode voltage. If the sum of the modulus values ​​is not less than the set value, the system fault is determined to be an inside-zone fault. If the sum of the modulus values ​​is less than the set value, the system fault is determined to be a forward outside-zone fault.

[0078] It should be noted that the set value is a threshold value that is preset based on specific parameters, operating conditions, and protection requirements of the DC distribution network.

[0079] This step compares the sum of the moduli of the high-frequency fault component of the 1-mode voltage calculated in step S6 with a pre-set threshold. Because the magnetic ring boundary affects the high-frequency signal differently for in-zone and out-of-zone faults, the high-frequency signal attenuates slightly for in-zone faults, while it significantly attenuates when passing through the boundary for out-of-zone faults. Therefore, if the sum of the moduli is not less than the set value, it indicates that the high-frequency fault energy is high and is determined to be an in-zone fault. If the sum of the moduli is less than the set value, it indicates that the high-frequency fault energy is low and is determined to be a positive out-of-zone fault.

[0080] This embodiment provides a DC distribution network fault detection method based on the high-frequency voltage on the line side of a magnetic ring boundary. This method performs DC distribution network fault detection based on the high-frequency voltage on the line side of a magnetic ring boundary. By utilizing the characteristics of the magnetic ring boundary for high-frequency signals, and through steps such as fault initiation judgment and transient power polarity judgment, combined with time-frequency analysis techniques such as Stockwell transform and synchronous squeeze transform, effective fault characteristics are extracted from the voltage on the line side of the magnetic ring. Compared with traditional methods, this method eliminates the need for complex two-terminal measurement and communication, and relies solely on the voltage information at the single-ended magnetic ring boundary to determine the fault direction and identify faults within and outside the zone. At the same time, through time-frequency analysis and energy redistribution, the high-frequency characteristics of the fault transient process can be more accurately captured, improving the accuracy and reliability of fault detection. This method can effectively solve the problem of rapid fault detection and location in DC distribution networks, and has strong engineering application value.

[0081] See also Figure 1 , Figure 1 The following illustrates an implementation process of a DC distribution network fault detection method based on the high-frequency voltage on the line side of a magnetic ring boundary designed based on the above embodiment. The implementation process is described below in conjunction with some other embodiments of the present invention. The implementation process includes the following steps:

[0082] Step 1: Collect the voltage on the line side of the magnetic ring and calculate the fault start criterion.

[0083] In one embodiment of the present invention, the fault start criterion is as follows:

[0084] (1)

[0085] Where, and Respectively represent the calculated values ​​of the positive and negative voltage starting criteria, and are the positive and negative voltages on the line side of the magnetic ring, Indicates the sampling interval, N s Indicates the number of sampling points in the data window. If the voltage start criteria of the positive and negative poles meet the following formula, the protection starts.

[0086] (2)

[0087] Where, If the above criterion is met, the system is disturbed and the process goes to step 2.

[0088] Step 2: Use the transient power polarity after the fault to determine the fault direction. If it is a positive fault, proceed to step 3.

[0089] Step 3: Calculate the 1-mode voltage fault component.

[0090] In one embodiment of the present invention, first, the voltage of the positive electrode and the negative electrode is used to calculate the 1-mode voltage, as shown in the following formula:

[0091] (3)

[0092] Where, Represents the 1-mode voltage. Based on the 1-mode voltage, the 1-mode voltage fault component is calculated as shown in the following formula:

[0093] (4)

[0094] Where, Indicates the 1-mode voltage in the data window before the fault. express The average value of .

[0095] Step 4: Calculate the Stockwel transform of the 1-mode voltage fault component.

[0096] In one embodiment of the present invention, the time-frequency distribution matrix determined by the Stockwel transform is as follows:

[0097] (5)

[0098] Where, represents the time-frequency distribution matrix of the 1-mode voltage fault component, Indicates the time point index, represents the sampling interval, Indicates the number of sampling points in the data window, Indicates the sampling point index, represents the frequency index, It represents the 1-mode voltage fault component, and i represents the imaginary unit.

[0099] Step 5: Perform a synchronized extrusion transformation.

[0100] In one embodiment of the present invention, first calculate The phase matrix is ​​then derived to obtain the instantaneous frequency matrix, and energy is redistributed according to the calculated instantaneous frequency, as shown in the following formula:

[0101] (6)

[0102] Where, represents the time-frequency distribution of the 1-mode voltage fault component after energy redistribution, represents the time variable, represents the frequency variable of the synchronized squeezed S transform, represents discrete frequency values, represents the length of the kth frequency interval, represents the instantaneous frequency matrix, represents the frequency interval, Indicates the frequency half the frequency interval.

[0103] Step 6: Calculate the sum of the modulus values ​​of the high-frequency fault components of the 1-mode voltage.

[0104] In one embodiment of the present invention, the sum of the modulo values ​​is calculated as follows:

[0105] (7)

[0106] Where, Indicates the effective frequency band range of the boundary, Indicates the data window length, Represents the sum of the modulus values ​​of the high-frequency fault components of the 1-mode voltage.

[0107] Step 7: Determine the fault inside and outside the zone, as shown in the following formula:

[0108] (8)

[0109] Where, Indicates the setting value of the fault judgment criteria inside and outside the zone.

[0110] Based on the same inventive concept, embodiments of the present application also provide a DC distribution network fault detection device based on high-frequency voltage at the magnetic ring boundary line side, for implementing the aforementioned DC distribution network fault detection method based on high-frequency voltage at the magnetic ring boundary line side. The solution provided by this device is similar to the solution described in the aforementioned method. Therefore, the specific limitations of the embodiments of the DC distribution network fault detection device based on high-frequency voltage at the magnetic ring boundary line side provided below can be found in the above-mentioned limitations of the DC distribution network fault detection method based on high-frequency voltage at the magnetic ring boundary line side, and will not be repeated here.

[0111] See also Figure 2 The embodiment of the present invention provides a DC distribution network fault detection device based on the high-frequency voltage on the line side of the magnetic ring boundary, comprising:

[0112] A startup judgment module is used to respond to a fault startup judgment criterion of the DC distribution network system to be detected; the fault startup judgment criterion is used to determine whether a disturbance occurs in the DC distribution network system;

[0113] The first fault judgment module is used to judge whether the fault direction is a forward fault by using the transient power polarity after the fault when the system is disturbed. If not, the system fault is judged to be a reverse fault. If so, proceed to the subsequent steps;

[0114] The first calculation module is used to calculate the 1st mode voltage fault component according to the positive and negative voltages on the magnetic ring line side;

[0115] The second calculation module is used to calculate the Stockwel transform of the 1-mode voltage fault component to obtain the time-frequency distribution matrix of the 1-mode voltage fault component;

[0116] The third calculation module is used to perform synchronous squeezing transformation on the time-frequency distribution matrix to obtain the time-frequency distribution of the 1-mode voltage fault component after energy redistribution;

[0117] A fourth calculation module is used to calculate the sum of the module values ​​of the high-frequency fault component of the 1-mode voltage based on the time-frequency distribution of the 1-mode voltage fault component;

[0118] The second fault judgment module judges the internal and external faults based on the sum of the module values ​​of the high-frequency fault components of the 1st module voltage. If the sum of the module values ​​is not less than the set value, the system fault is judged to be an internal fault. If the sum of the module values ​​is less than the set value, the system fault is judged to be a forward external fault.

[0119] Those skilled in the art can clearly understand that, for the convenience and brevity of description, only the division of the above-mentioned functional units and modules is used as an example for illustration. In actual applications, the above-mentioned functions can be distributed and completed by different functional units and modules as needed, that is, the internal structure of the system can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiment can be integrated into one processing unit, or each unit can exist physically alone, or two or more units can be integrated into one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of this application. The specific working process of the units and modules in the above-mentioned system can refer to the corresponding process in the aforementioned method embodiment, and will not be repeated here.

[0120] Reference Figure 3 An embodiment of the present invention further provides a computer device, comprising: a memory and a processor and a computer program stored in the memory. When the computer program is executed on the processor, a DC distribution network fault detection method based on the high-frequency voltage on the magnetic ring boundary line side as described in any one of the above methods is implemented.

[0121] The computer device may be a desktop computer, notebook computer, PDA, cloud server or other computing device. The computer device may include, but is not limited to, a processor and a memory. It will be understood by those skilled in the art that Figure 3 The computer device is merely an example and does not constitute a limitation on the computer device. The computer device may include more or fewer components than shown in the figure, or a combination of certain components, or different components. For example, the computer device may also include input and output devices, network access devices, etc.

[0122] The processor may be a central processing unit (CPU), other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA), other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor.

[0123] In some embodiments, the memory may be an internal storage unit of the computer device, such as a hard drive or memory of the computer device. In other embodiments, the memory may also be an external storage device of the computer device, such as a plug-in hard drive, a Smart Media Card (SMC), a Secure Digital (SD) card, a flash memory card, etc. equipped with the computer device. Furthermore, the memory may include both an internal storage unit of the computer device and an external storage device. The memory is used to store an operating system, application programs, a boot loader, data, and other programs, such as the program code of the computer program. The memory may also be used to temporarily store data that has been output or is about to be output.

[0124] An embodiment of the present invention further provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the method for detecting a fault in a DC distribution network based on the high-frequency voltage on the line side of a magnetic ring boundary as described in any one of the above methods is implemented.

[0125] In this embodiment, if the integrated unit is implemented as a software functional unit and sold or used as a standalone product, it can be stored in a computer-readable storage medium. Based on this understanding, the present application can implement all or part of the process steps in the above-mentioned method embodiments by using a computer program to instruct the relevant hardware. The computer program can be stored in a computer-readable storage medium. When executed by a processor, the computer program can implement the steps of each of the above-mentioned method embodiments. The computer program includes computer program code, which can be in source code form, object code form, executable file, or some intermediate form. The computer-readable medium can include at least: any entity or device capable of carrying computer program code to a camera / terminal device, recording medium, computer memory, read-only memory (ROM), random access memory (RAM), electric carrier signals, telecommunication signals, and software distribution media. Examples include USB flash drives, removable hard drives, magnetic disks, or optical disks. In some jurisdictions, based on legislation and patent practice, computer-readable media cannot be electric carrier signals or telecommunication signals.

[0126] An embodiment of the present invention provides a computer program product, including a computer program. When the computer program is executed by a processor, the computer program implements the DC distribution network fault detection method based on the high-frequency voltage on the line side of the magnetic ring boundary as described in any one of the above methods.

[0127] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant description of other embodiments.

[0128] Those skilled in the art will appreciate that the units and algorithm steps of each example 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 beyond the scope of this application.

[0129] In the embodiments disclosed in the present application, it should be understood that the disclosed devices / terminal equipment and methods can be implemented in other ways. For example, the device / terminal equipment embodiments described above are merely schematic. For example, the division of the modules or units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0130] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. 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 various embodiments of the present invention.

Claims

1. A DC distribution network fault detection method based on high-frequency voltage on the line side of a magnetic ring boundary, characterized in that: The steps include: responding to a fault start criterion of a DC power distribution network system to be detected; the fault start criterion is used to determine whether a disturbance occurs in the DC power distribution network system; If the system is disturbed, the transient power polarity after the fault is used to determine whether the fault direction is a forward fault. If not, the system fault is determined to be a reverse fault. If so, proceed to the subsequent steps. Calculate the 1-mode voltage fault component based on the positive and negative voltages on the magnetic ring line side; Calculating the Stockwel transform of the 1-mode voltage fault component to obtain a time-frequency distribution matrix of the 1-mode voltage fault component; Performing synchronous squeezing transformation on the time-frequency distribution matrix to obtain the time-frequency distribution of the 1-mode voltage fault component after energy redistribution; Calculating the sum of the modulus values ​​of the high-frequency fault component of the 1-mode voltage based on the time-frequency distribution of the 1-mode voltage fault component; The internal and external faults are judged based on the sum of the modulus values ​​of the high-frequency fault components of the 1-mode voltage. If the sum of the modulus values ​​is not less than the set value, the system fault is judged to be an internal fault. If the sum of the modulus values ​​is less than the set value, the system fault is judged to be a positive external fault.

2. The DC distribution network fault detection method based on the high-frequency voltage on the magnetic ring boundary line side according to claim 1 is characterized in that: The fault start criterion is as follows: Where, and They represent the calculated value of the positive voltage startup criterion and the calculated value of the negative voltage startup criterion respectively. Indicates the setting value of the start criterion; The calculation formula for the voltage starting criterion calculation value of the positive and negative electrodes is as follows: Where, and Indicates the positive and negative voltages on the magnetic ring line side. represents the sampling interval, Indicates the current calculation time index, Indicates the number of sampling points in the data window, Indicates the sampling point index within the data window.

3. The DC distribution network fault detection method based on the high-frequency voltage on the magnetic ring boundary line side according to claim 2 is characterized in that: The starting criterion in response to a fault of the DC distribution network system to be detected includes: Collect the voltage on the magnetic ring line side and calculate the voltage start criterion value; Based on the voltage start criterion calculation value, it is determined whether the fault start criterion is satisfied. If so, it is determined that a disturbance occurs in the system.

4. The DC distribution network fault detection method based on the high-frequency voltage on the magnetic ring boundary line side according to claim 1, characterized in that: Calculate the 1-mode voltage fault component based on the positive and negative voltages on the magnetic ring line side, including: The voltage of the positive and negative electrodes is used to calculate the 1-mode voltage as follows: Where, Indicates 1-mode voltage, and Indicates the positive and negative voltages on the line side of the magnetic ring; The 1-mode voltage fault component is calculated using the 1-mode voltage as follows: Where, Indicates the 1-mode voltage fault component, Indicates the 1-mode voltage in the data window before the fault. express The average value of .

5. The DC distribution network fault detection method based on the high-frequency voltage on the magnetic ring boundary line side according to claim 1, characterized in that: The time-frequency distribution matrix of the 1-mode voltage fault component is calculated according to the following formula: Where, represents the time-frequency distribution matrix of the 1-mode voltage fault component, Indicates the time point index, represents the sampling interval, Indicates the number of sampling points in the data window, Indicates the sampling point index, represents the frequency index, It represents the 1-mode voltage fault component, and i represents the imaginary unit.

6. The DC distribution network fault detection method based on the high-frequency voltage on the magnetic ring boundary line side according to claim 1, characterized in that: The time-frequency distribution of the 1-mode voltage fault component after energy redistribution is determined according to the following formula: Where, represents the time-frequency distribution of the 1-mode voltage fault component after energy redistribution, represents the time variable, represents the frequency variable of the synchronized squeezed S transform, represents discrete frequency values, represents the length of the kth frequency interval, represents the instantaneous frequency matrix, represents the frequency interval, Indicates the frequency Half the frequency interval at Represents the time-frequency distribution matrix of the 1-mode voltage fault component.

7. The DC distribution network fault detection method based on the high-frequency voltage on the line side of the magnetic ring boundary according to claim 1 is characterized in that: The sum of the modulus values ​​of the high-frequency fault components of the 1-mode voltage is determined according to the following formula: Where, represents the sum of the modulus values ​​of the high-frequency fault components of the 1-mode voltage, represents the frequency variable of the synchronized squeezed S-transform, Indicates the effective frequency band range of the boundary, represents the time variable, Indicates the data window length, It represents the time-frequency distribution of the 1-mode voltage fault component after energy redistribution.

8. A DC distribution network fault detection device based on high-frequency voltage on the line side of a magnetic ring boundary, characterized in that: include: A startup judgment module, used to respond to the fault startup judgment criteria of the DC distribution network system to be detected; The fault start criterion is used to determine whether a disturbance occurs in the DC distribution network system; The first fault judgment module is used to judge whether the fault direction is a forward fault by using the transient power polarity after the fault when the system is disturbed. If not, the system fault is judged to be a reverse fault. If so, proceed to the subsequent steps; The first calculation module is used to calculate the 1st mode voltage fault component according to the positive and negative voltages on the magnetic ring line side; A second calculation module is used to calculate the Stockwel transform of the 1-mode voltage fault component to obtain the time-frequency distribution matrix of the 1-mode voltage fault component; A third calculation module is used to perform synchronous squeezing transformation on the time-frequency distribution matrix to obtain the time-frequency distribution of the 1-mode voltage fault component after energy redistribution; A fourth calculation module, configured to calculate the sum of the module values ​​of the high-frequency fault component of the first mode voltage based on the time-frequency distribution of the first mode voltage fault component; The second fault judgment module judges the internal and external faults based on the sum of the module values ​​of the high-frequency fault components of the 1-module voltage. If the sum of the module values ​​is not less than the set value, the system fault is judged to be an internal fault. If the sum of the module values ​​is less than the set value, the system fault is judged to be a forward external fault.

9. A computer device, characterized in that: The device includes a processor and a memory: The memory is used to store the computer program and send instructions of the computer program to the processor; The processor executes the DC distribution network fault detection method based on the high-frequency voltage on the line side of the magnetic ring boundary according to any one of claims 1 to 7 according to the instructions of the computer program.

10. 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 the processor, the method for detecting faults in a DC distribution network based on high-frequency voltage on the line side of a magnetic ring boundary according to any one of claims 1 to 7 is implemented.

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