Distribution network traveling wave ranging device, distribution terminal, fault monitoring system and method

Abstract

This application provides a traveling wave ranging device, distribution terminal, fault monitoring system, and method for distribution networks, relating to the field of distribution network fault monitoring technology. The device includes: a current transformer for acquiring voltage / current traveling wave signals at corresponding detection points; a data processing unit, including: a phase-mode transformation module for performing phase-mode transformation on the voltage / current traveling wave signals to extract the line-mode components of each voltage / current traveling wave signal; a wavelet analysis module for decomposing the extracted line-mode components based on wavelet transform to obtain corresponding wavelet transform coefficients, performing modulus maxima search on all obtained wavelet transform coefficients, and generating a first detection signal representing the detection of the target modulus maxima if a target modulus maxima representing a line fault is determined; and a ranging calculation unit for determining the first fault location information based on the first detection signal. This application enables high-speed sampling and processing of traveling wave data, effectively improving the accuracy of distribution network fault location.

Description

Technical Field

[0001] This application relates to the field of power distribution network fault monitoring technology, specifically to a power distribution network traveling wave ranging device, a power distribution terminal, a power distribution network fault monitoring system, a power distribution network fault monitoring method, a power distribution network fault monitoring device, a machine-readable storage medium, and a terminal equipment. Background Technology

[0002] Currently, existing fault location methods in distribution networks typically rely on distribution automation systems and fault indicators, resulting in low fault location accuracy and requiring significant post-fault line patrols, failing to meet the demand for precise fault location. To achieve accurate fault location, the traveling wave method is commonly used. Its basic principle is to employ distributed monitoring to break down the complex distribution network lines into simpler ones, enabling high-precision and rapid fault location. The traveling wave method is further divided into single-end ranging and double-end ranging methods. The single-end method calculates the fault distance by detecting the time difference between the arrival of the initial traveling wave and the first reflected wave at the fault point; the double-end method locates the fault by detecting the time difference between the arrival of the traveling wave generated at the fault point at both ends of the line.

[0003] However, since power distribution lines often include overhead lines, cable lines, and branch lines, traveling waves undergo complex refraction and reflection during their movement. Identifying these different reflected traveling wave surges at one end of the line is very difficult. Therefore, it is difficult to accurately determine the location of the fault point using only the single-end traveling wave fault location principle. Double-end traveling wave fault location only needs to accurately detect the time when the initial traveling wave front of the fault arrives at the detection point, without considering the refraction and reflection of subsequent waves. However, since there are many branches in the power distribution network, applying double-end traveling wave location devices to all branches would result in high costs and difficult maintenance in the later stages. Summary of the Invention

[0004] The purpose of this application is to provide a traveling wave ranging device, distribution terminal, fault monitoring system and method for power distribution networks to solve the above problems.

[0005] To achieve the above objectives, the first aspect of this application provides a traveling wave ranging device for a distribution network, comprising:

[0006] The current transformer installed on the corresponding pole-mounted switch pole is used to collect the voltage / current traveling wave signal at the corresponding detection point;

[0007] The data processing unit includes:

[0008] A phase-mode conversion module is used to perform phase-mode conversion on the voltage / current traveling wave signals to extract the line-mode components of each voltage / current traveling wave signal;

[0009] The wavelet analysis module is used to extract fault feature information from the extracted line mode components;

[0010] Among these steps, fault feature information is extracted from the extracted line mode components, including:

[0011] The extracted line mode components are decomposed based on wavelet transform to obtain the corresponding wavelet transform coefficients. A preset modulus maxima search algorithm is called to search for modulus maxima of all obtained wavelet transform coefficients. If the modulus maxima search algorithm determines that there is a target modulus maxima representing a line fault, a first detection signal representing the detection of the target modulus maxima is generated. The first detection signal represents the detection of the target modulus maxima.

[0012] The ranging calculation unit is used to receive the first detection signal generated by the wavelet analysis module and determine the first fault location information based on the received first detection signal.

[0013] Optionally, the power distribution network traveling wave ranging device further includes:

[0014] The signal conversion unit is used to perform analog-to-digital conversion on the acquired voltage / current traveling wave signal, wherein the voltage / current traveling wave signal after analog-to-digital conversion is a serial differential signal;

[0015] The data processing unit further includes a data buffer module, which is used to buffer the voltage / current traveling wave signal after analog-to-digital conversion into at least two designated buffer areas after serial-to-parallel conversion, and to perform alternating read and write control on the voltage / current traveling wave signal buffered in at least two designated buffer areas, so that when new data is written to one buffer area, the other buffer area can be read.

[0016] Optionally, the power distribution network traveling wave ranging device further includes:

[0017] The signal conditioning unit is used to preprocess the voltage / current traveling wave signal acquired by the transformer, and to send the preprocessed voltage / current traveling wave signal to the signal conversion unit.

[0018] The preprocessing includes at least amplification and filtering of the voltage / current traveling wave signals acquired by the transformer.

[0019] Optionally, the data processing unit includes:

[0020] The high-speed acquisition module is used to send control signals and clock signals to the signal conversion unit to acquire data from the voltage / current traveling wave signal from the signal conversion unit, and to convert the serial differential signal from the signal conversion unit into parallel multi-bit data.

[0021] Optionally, the data caching module includes:

[0022] An input asynchronous buffer, an output asynchronous buffer, a first random access memory, a second random access memory, and a buffer controller;

[0023] The input asynchronous buffer is used to buffer the voltage / current traveling wave signal from the high-speed acquisition module;

[0024] The buffer controller is configured to sequentially read voltage / current traveling wave signals from the input asynchronous buffer and alternately store the read voltage / current traveling wave signals into the first random access memory and the second random access memory, and alternately read voltage / current traveling wave signals from the first random access memory and the second random access memory and sequentially store the read voltage / current traveling wave signals into the output asynchronous buffer.

[0025] Optionally, the read voltage / current traveling wave signals are alternately stored in the first random access memory and the second random access memory, including:

[0026] Determine the number of the voltage / current traveling wave signal read;

[0027] If the current voltage / current traveling wave signal number is odd, store the current voltage / current traveling wave signal in the first random access memory; if the current voltage / current traveling wave signal number is even, store the current voltage / current traveling wave signal in the second random access memory.

[0028] Optionally, alternatingly reading voltage / current traveling wave signals from the first random access memory and the second random access memory includes:

[0029] When a voltage / current traveling wave signal is written to the first random access memory, a voltage / current traveling wave signal is read from the second random access memory; or

[0030] When a voltage / current traveling wave signal is written to the second random access memory, a voltage / current traveling wave signal is read from the first random access memory.

[0031] Optionally, the phase mode transformation module is used to perform phase mode transformation on the voltage / current traveling wave signals read from the output asynchronous buffer sequentially based on the Kelvin transform matrix to extract the line mode components of each voltage / current traveling wave signal.

[0032] Optionally, the data processing unit further includes:

[0033] The fault analysis module is used to compare the extracted line mode components for each voltage / current traveling wave signal for which fault feature information has been extracted, and to determine the fault detection result based on the comparison results of each line mode component.

[0034] Optionally, the modulus maximum search algorithm includes:

[0035] S1. Determine the wavelet coefficient threshold and the initial modulus maxima;

[0036] S2. Obtain wavelet transform coefficients, compare the current wavelet transform coefficients with the wavelet coefficient threshold, if the absolute value of the current wavelet transform coefficients is greater than the wavelet coefficient threshold, proceed to step S3; otherwise, proceed to step S2.

[0037] S3. Compare the current wavelet transform coefficients with the initial modulus maxima. If the current wavelet transform coefficients are greater than the initial modulus maxima, update the current initial modulus maxima with the absolute value of the current wavelet coefficients and proceed to step S4. Otherwise, proceed to step S5.

[0038] S4. Set the modulus maximum value flag to the first flag and determine whether the current search count is greater than the preset search count threshold. If it is greater, proceed to step S6; otherwise, proceed to step S2.

[0039] S5. Determine whether the current maximum value flag has been set to the first flag. If yes, determine whether the current search count is greater than the search count threshold. If it is greater, execute step S6; otherwise, execute step S2.

[0040] S6. Using the current initial modulus maximum as the target modulus maximum, generate a first detection signal representing the detection of the target modulus maximum.

[0041] Optionally, after updating the current initial modulus maxima with the absolute values ​​of the current wavelet coefficients, the modulus maxima search algorithm further includes:

[0042] Determine whether the current wavelet transform coefficient values ​​are greater than zero;

[0043] If the current wavelet transform coefficient value is greater than zero, the polarity of the current wavelet coefficient is determined to be positive; if the current wavelet transform coefficient value is less than or equal to zero, the polarity of the current wavelet coefficient is determined to be negative.

[0044] Optionally, after generating a first detection signal representing the detection of a target modulus maxima, the wavelet analysis module is further configured to:

[0045] A second detection signal is generated to characterize whether the target modulus maxima is positive or negative, and the generated second detection signal is sent to the ranging calculation unit.

[0046] Optionally, generating a second detection signal characterizing whether the target modulus maxima is positive or negative includes:

[0047] If the polarity of the target modulus maximum is determined to be positive, a first-level signal for multiple consecutive cycles is output.

[0048] If the polarity of the target modulus maximum is determined to be negative, a second-level signal with multiple consecutive cycles is output.

[0049] Optionally, the first detection signal includes:

[0050] The first level signal for multiple consecutive cycles.

[0051] Optionally, the line mode components of each voltage / current traveling wave signal include:

[0052] The first linear mode component corresponding to the A-phase voltage / current of the voltage / current traveling wave signal, the second linear mode component corresponding to the B-phase voltage / current of the voltage / current traveling wave signal, and the third linear mode component corresponding to the C-phase voltage / current of the voltage / current traveling wave signal;

[0053] The fault detection results are determined based on the comparison results of each linear modulus component, including:

[0054] If the absolute values ​​of any two of the extracted first line mode component, second line mode component, and third line mode component are equal, and the value of the other one is zero, the fault detection result is determined to be a single-phase ground fault.

[0055] If the absolute value of any one of the extracted first line mode component, second line mode component, and third line mode component is greater than the absolute values ​​of the other two, the fault detection result is determined to be a two-phase ground short circuit fault.

[0056] If the absolute value of any one of the extracted first linear mode component, second linear mode component, and third linear mode component is equal to twice the absolute value of the other two, the fault detection result is determined to be a two-phase short circuit fault.

[0057] If the absolute values ​​of the extracted first, second, and third line-mode components are all greater than zero, and the absolute values ​​of the extracted first, second, and third line-mode components are all different, the fault detection result is determined to be a three-phase ground fault.

[0058] Optionally, the ranging calculation unit is further configured to:

[0059] When the first detection signal is received for the first time, a first time when the first detection signal is received for the first time is determined, and if the first detection signal is received again within a first interval, a second time when the first detection signal is received again is determined, and the time difference between the first time and the second time is determined.

[0060] The first fault location information is determined based on the received first detection signal, including:

[0061] Obtain the second detection signal corresponding to the first detection signal received for the first time, and obtain the second detection signal corresponding to the first detection signal received again;

[0062] The first fault location information is determined by calling the corresponding single-end ranging algorithm based on the comparison result between the first received second detection signal and the second received second detection signal.

[0063] Optionally, the first fault location information is determined by calling the corresponding single-ended ranging algorithm based on the comparison result between the first received second detection signal and the second detection signal received subsequently, including:

[0064] If the polarity represented by the first received second detection signal is the same as that represented by the second received second detection signal, the first fault location information is determined by the following algorithm:

[0065]

[0066] Among them, D single t1 represents the distance from the fault point to the current detection point, v represents the transmission speed of the voltage / current traveling wave signal, t1 represents the first time, and t2 represents the second time.

[0067] Optionally, the first fault location information is determined by calling the corresponding single-ended ranging algorithm based on the comparison result between the first received second detection signal and the second detection signal received subsequently, including:

[0068] If the polarity represented by the first received second detection signal is different from that represented by the second detected signal received subsequently, the first fault location information is determined using the following algorithm:

[0069]

[0070] Among them, D single The distance from the fault point to the current detection point is represented by v, the transmission speed of the voltage / current traveling wave signal is represented by t1, the first time is represented by t2, the second time is represented by L, and the distance between the current detection point and the nearest endpoint on the power distribution line where the current detection point is located is represented by L. There are multiple detection points on the power distribution line where the current detection point is located, and there are no other detection points between the current detection point and the endpoint.

[0071] A second aspect of this application provides a power distribution terminal, comprising:

[0072] Control unit; and

[0073] The aforementioned traveling wave ranging device for power distribution networks;

[0074] The control unit is communicatively connected to the ranging calculation unit of the power distribution network traveling wave ranging device, and is used to receive the first time, first fault location information and fault detection results sent by the ranging calculation unit.

[0075] A third aspect of this application provides a power distribution network fault monitoring system, comprising:

[0076] Main site; and

[0077] Multiple power distribution terminals as described above;

[0078] The master station is communicatively connected to each power distribution terminal and is used to receive the first time, first fault location information and fault detection results sent by each power distribution terminal, as well as the second fault location information to determine the fault point based on the received first time or first fault location information.

[0079] A fourth aspect of this application provides a method for monitoring faults in a power distribution network, applied to a master station in the aforementioned power distribution network fault monitoring system, the method comprising:

[0080] In response to the first time or first fault location information sent by any power distribution terminal, determine whether any side of the current power distribution terminal is the endpoint of the current power distribution line;

[0081] If any side of the current power distribution terminal is the endpoint of the current power distribution line, determine whether the current power distribution terminal receives the first time or first fault location information sent by the first adjacent power distribution terminal on the current power distribution line within a preset time range;

[0082] If the first time or first fault location information sent by the first adjacent power distribution terminal is received within the preset time range, it is determined that the fault point is located between the current power distribution terminal and the adjacent power distribution terminal, and the dual-end ranging algorithm is called to calculate the second fault location information of the fault point;

[0083] If the first time or first fault location information sent by the first adjacent power distribution terminal is not received within the preset time range, it is determined that the fault point is located between the current power distribution terminal and the endpoint of its corresponding current power distribution line, and the first fault location information is used as the second fault location information.

[0084] If neither side of the current power distribution terminal is an endpoint of the current power distribution line, and the first fault location information sent by the first adjacent power distribution terminal is received within the preset time range, the dual-end ranging algorithm is invoked to calculate the second fault location information of the fault point.

[0085] Optionally, determining whether any side of the current power distribution terminal is an endpoint of the current power distribution line includes:

[0086] If there are no other distribution terminals between the current distribution terminal and any endpoint of the current distribution line it is located on, then the corresponding side of the current distribution terminal is determined to be the endpoint of the current distribution line; otherwise, the corresponding side of the current distribution terminal is determined not to be the endpoint of the current distribution line.

[0087] Optionally, the two-end ranging algorithm includes:

[0088] Obtain the distance between the current power distribution terminal and the first adjacent power distribution terminal, and obtain the transmission speed of the voltage / current traveling wave signal;

[0089] Based on the distance between the current power distribution terminal and the first adjacent power distribution terminal, the transmission speed of the voltage / current traveling wave signal, the first time from the current power distribution terminal and the first time from the first adjacent power distribution terminal, the first distance between the current power distribution terminal and the fault point is calculated through a preset first ranging model, and the second distance between the first adjacent power distribution terminal and the fault point is calculated.

[0090] If there are no other branch power lines between the current power distribution terminal and the first adjacent power distribution terminal, the second fault location information of the fault point is determined based on the first distance or the second distance.

[0091] Optionally, the two-end ranging algorithm further includes:

[0092] If there are other branch distribution lines between the current distribution terminal and the first adjacent distribution terminal, obtain the third distance between the current distribution terminal and the branch connection point of the corresponding branch distribution line on the current distribution line, and obtain the first time sent by the second adjacent distribution terminal closest to the branch connection point on the corresponding branch distribution line, and the fourth distance between the second adjacent distribution terminal and the branch connection point.

[0093] If the first distance is different from the third distance, the second fault location information of the fault point is determined based on the first distance or the second distance;

[0094] If the first distance is the same as the third distance, based on the third distance, the fourth distance, the transmission speed of the voltage / current traveling wave signal, the first time from the current power distribution terminal and the first time from the second adjacent power distribution terminal, the fifth distance between the current power distribution terminal and the fault point, and the sixth distance between the second adjacent power distribution terminal and the fault point are calculated by a preset second ranging model.

[0095] The second fault location information is determined based on the fifth distance or the sixth distance.

[0096] Optionally, the first ranging model includes:

[0097]

[0098] Among them, D AF D represents the first distance between the current power distribution terminal and the fault point. BF The second distance between the first adjacent distribution terminal and the fault point is given by T, where v is the transmission speed of the voltage / current traveling wave signal, and T is the distance between the first adjacent distribution terminal and the fault point. FA For the first time from the current power distribution terminal, T FB For the first time from the first adjacent power distribution terminal, L AB The distance between the current power distribution terminal and the first adjacent power distribution terminal is denoted as .

[0099] Optionally, the second ranging model includes:

[0100]

[0101] Among them, D AF D represents the fifth distance between the current power distribution terminal and the fault point. CF The distance between the second adjacent distribution terminal and the fault point is the sixth distance, v is the transmission speed of the voltage / current traveling wave signal, and T is the distance between the second adjacent distribution terminal and the fault point. FA For the first time from the current power distribution terminal, T FC For the first time from the second adjacent distribution terminal, L AO L is the third distance between the current power distribution terminal and the branch contact point. CO This is the fourth distance between the second adjacent power distribution terminal and the branch connection point.

[0102] A fifth aspect of this application provides a power distribution network fault monitoring device, which applies the above-described power distribution network fault monitoring method, the device comprising:

[0103] The information receiving module is configured to respond to the first time or first fault location information sent by any power distribution terminal and determine whether any side of the current power distribution terminal is the endpoint of the current power distribution line.

[0104] The judgment module is configured to determine whether, within a preset time range, it receives first time or first fault location information sent by the first adjacent power distribution terminal on the current power distribution line if either side of the current power distribution terminal is the endpoint of the current power distribution line.

[0105] The ranging calculation module is configured to, if it receives the first time or first fault location information sent by the first adjacent power distribution terminal within the preset time range, determine that the fault point is located between the current power distribution terminal and the adjacent power distribution terminal, and call the dual-end ranging algorithm to calculate the second fault location information of the fault point;

[0106] If no first time or first fault location information is received from the first adjacent power distribution terminal within the preset time range, it is determined that the fault point is located between the current power distribution terminal and the endpoints of its corresponding current power distribution line, and the first fault location information is used as the second fault location information; and

[0107] If neither side of the current power distribution terminal is an endpoint of the current power distribution line, and the first fault location information sent by the first adjacent power distribution terminal is received within the preset time range, the dual-end ranging algorithm is invoked to calculate the second fault location information of the fault point.

[0108] Optionally, determining whether any side of the current power distribution terminal is an endpoint of the current power distribution line includes:

[0109] If there are no other distribution terminals between the current distribution terminal and any endpoint of the current distribution line it is located on, then the corresponding side of the current distribution terminal is determined to be the endpoint of the current distribution line; otherwise, the corresponding side of the current distribution terminal is determined not to be the endpoint of the current distribution line.

[0110] Optionally, the two-end ranging algorithm includes:

[0111] Obtain the distance between the current power distribution terminal and the first adjacent power distribution terminal, and obtain the transmission speed of the voltage / current traveling wave signal;

[0112] Based on the distance between the current power distribution terminal and the first adjacent power distribution terminal, the transmission speed of the voltage / current traveling wave signal, the first time from the current power distribution terminal and the first time from the first adjacent power distribution terminal, the first distance between the current power distribution terminal and the fault point is calculated through a preset first ranging model, and the second distance between the first adjacent power distribution terminal and the fault point is calculated.

[0113] If there are no other branch power lines between the current power distribution terminal and the first adjacent power distribution terminal, the second fault location information of the fault point is determined based on the first distance or the second distance.

[0114] Optionally, the two-end ranging algorithm further includes:

[0115] If there are other branch distribution lines between the current distribution terminal and the first adjacent distribution terminal, obtain the third distance between the current distribution terminal and the branch connection point of the corresponding branch distribution line on the current distribution line, and obtain the first time sent by the second adjacent distribution terminal closest to the branch connection point on the corresponding branch distribution line, and the fourth distance between the second adjacent distribution terminal and the branch connection point.

[0116] If the first distance is different from the third distance, the second fault location information of the fault point is determined based on the first distance or the second distance;

[0117] If the first distance is the same as the third distance, based on the third distance, the fourth distance, the transmission speed of the voltage / current traveling wave signal, the first time from the current power distribution terminal and the first time from the second adjacent power distribution terminal, the fifth distance between the current power distribution terminal and the fault point, and the sixth distance between the second adjacent power distribution terminal and the fault point are calculated by a preset second ranging model.

[0118] The second fault location information is determined based on the fifth distance or the sixth distance.

[0119] Optionally, the first ranging model includes:

[0120]

[0121] Among them, D AF D represents the first distance between the current power distribution terminal and the fault point. BF The second distance between the first adjacent distribution terminal and the fault point is given by T, where v is the transmission speed of the voltage / current traveling wave signal, and T is the distance between the first adjacent distribution terminal and the fault point. FA For the first time from the current power distribution terminal, T FB For the first time from the first adjacent power distribution terminal, L AB The distance between the current power distribution terminal and the first adjacent power distribution terminal is denoted as .

[0122] Optionally, the second ranging model includes:

[0123]

[0124] Among them, D AF D represents the fifth distance between the current power distribution terminal and the fault point. CF The distance between the second adjacent distribution terminal and the fault point is the sixth distance, v is the transmission speed of the voltage / current traveling wave signal, and T is the distance between the second adjacent distribution terminal and the fault point. FA For the first time from the current power distribution terminal, T FC For the first time from the second adjacent distribution terminal, L AO L is the third distance between the current power distribution terminal and the branch contact point. CO This is the fourth distance between the second adjacent power distribution terminal and the branch connection point.

[0125] In a sixth aspect, this application provides a machine-readable storage medium storing instructions that, when executed by a processor, configure the processor to perform the power distribution network fault monitoring method described above.

[0126] In a seventh aspect, this application provides a terminal device including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the power distribution network fault monitoring method described above.

[0127] The traveling wave ranging device for distribution networks disclosed in this application can be installed in a distribution terminal unit (FTU). It detects traveling wave signals through current transformers mounted on pole-mounted switch poles and enables communication between the FTU and the master station, thereby effectively reducing investment and construction costs and simplifying construction and modification. Furthermore, the device enables high-speed sampling and processing of traveling wave data, accurately capturing the traveling wave front through phase-mode transformation, effectively improving the accuracy of fault location in distribution networks.

[0128] Other features and advantages of the embodiments of this application will be described in detail in the following detailed description section. Attached Figure Description

[0129] The accompanying drawings are provided to further illustrate the embodiments of this application and form part of the specification. They are used together with the following detailed description to explain the embodiments of this application, but do not constitute a limitation on the embodiments of this application. In the drawings:

[0130] Figure 1 This is a schematic diagram of the structure of the power distribution network traveling wave ranging device provided in a preferred embodiment of this application;

[0131] Figure 2 This is a schematic diagram of the data processing unit structure provided in a preferred embodiment of this application;

[0132] Figure 3 This is a schematic diagram of phase mode transformation provided for a preferred embodiment of this application;

[0133] Figure 4 A flowchart for modulus maxima detection provided in a preferred embodiment of this application;

[0134] Figure 5 A flowchart of the modulus maximum search algorithm provided in the preferred embodiment of this application;

[0135] Figure 6 A fault detection flowchart provided for a preferred embodiment of this application;

[0136] Figure 7 This is a schematic diagram of the distance measurement calculation unit provided in a preferred embodiment of this application;

[0137] Figure 8 A flowchart for strategy determination provided in a preferred embodiment of this application;

[0138] Figure 9A typical wiring diagram of a power distribution network provided for a preferred embodiment of this application;

[0139] Figure 10 A schematic block diagram of a power distribution network fault monitoring device provided in a preferred embodiment of this application;

[0140] Figure 11 A schematic diagram of a terminal device provided for a preferred embodiment of this application.

[0141] Explanation of reference numerals in the attached figures

[0142] 10 - Terminal device, 100 - Processor, 101 - Memory, 102 - Computer program. Detailed Implementation

[0143] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only for illustration and explanation of the embodiments of this application and are not intended to limit the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0144] It should be noted that the technical solutions of the various embodiments of this application can be combined with each other, but only if they are based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by this application.

[0145] like Figure 1 As shown, the first aspect of this application provides a traveling wave ranging device for a distribution network, comprising: a current transformer installed on a corresponding pole-mounted switch pole for acquiring voltage / current traveling wave signals at corresponding detection points; a data processing unit, comprising: a phase-mode transformation module for performing phase-mode transformation on the voltage / current traveling wave signals to extract line-mode components of each voltage / current traveling wave signal; a wavelet analysis module for extracting fault feature information from the extracted line-mode components; wherein, extracting fault feature information from the extracted line-mode components includes: decomposing the extracted line-mode components based on wavelet transform to obtain corresponding wavelet transform coefficients, calling a preset modulus maxima search algorithm to perform modulus maxima search on all obtained wavelet transform coefficients, and if the modulus maxima search algorithm determines that there exists a target modulus maxima representing a line fault, generating a first detection signal representing the detection of the target modulus maxima; and a ranging calculation unit for receiving the first detection signal generated by the wavelet analysis module and determining first fault location information based on the received first detection signal.

[0146] Thus, the traveling wave ranging device for distribution networks of this application can be installed in a distribution terminal unit (FTU). It detects traveling wave signals through current transformers mounted on pole-mounted switch poles, enabling communication between the FTU and the master station, thereby effectively reducing investment and construction costs and simplifying construction and modification. Simultaneously, the device of this application can achieve high-speed sampling and processing of traveling wave data, accurately capturing the traveling wave front through phase mode transformation, effectively improving the accuracy of distribution network fault location.

[0147] Understandably, pole-mounted switches are safety switches used on utility poles to ensure electrical safety, primarily for isolating high voltage in circuits. Currently, distribution terminals (FTUs) are installed at critical nodes in the distribution network, such as main line tie switches, necessary sectionalizing switches, and general nodes, such as branch switches. This application integrates or externally places traveling wave transformers into the pole-mounted switch's terminals, using these terminals as detection points to acquire voltage / current traveling wave signals. The traveling wave ranging device of this application can be installed as a standalone device at the corresponding pole-mounted switch, such as on the pole corresponding to the switch, or integrated into the existing FTU.

[0148] The traveling wave fault location device for power distribution networks in this application further includes: a signal conversion unit for performing analog-to-digital conversion on the acquired voltage / current traveling wave signal, wherein the voltage / current traveling wave signal after analog-to-digital conversion is a serial differential signal; and a signal conditioning unit for preprocessing the voltage / current traveling wave signal acquired by the instrument transformer and sending the preprocessed voltage / current traveling wave signal to the signal conversion unit. The preprocessing includes at least amplification and filtering of the voltage / current traveling wave signal acquired by the instrument transformer to adjust the small current and small voltage signals on the secondary side of the instrument transformer to the analog signal input range of the signal conversion unit, and denoising the traveling wave signal to ensure accurate sampling data from the signal conversion unit and to minimize the impact of noise on fault location accuracy. It is understood that the signal conditioning unit can be implemented using existing signal conditioning circuits, and this is not limited here.

[0149] In this application, the signal conversion unit is an AD acquisition circuit, such as an AD converter or an AD sampling chip. The AD converter converts the pre-processed voltage / current traveling wave signal from analog to digital, so that the data processing unit can process the converted voltage / current traveling wave signal. Since the fault transient voltage and current traveling waves on the distribution line are high-frequency signals, their spectrum is mainly distributed in the range of 10kHz to 100kHz. In order to acquire the transient traveling wave signal on the line on the secondary side, the voltage and current signal conversion circuit needs to have high accuracy, good stability, and fast response speed. Therefore, the A / D converter in this application has an acquisition rate of 5MSPS or higher and a data bit width of 12 bits or higher to ensure high positioning accuracy. The input of the traveling wave signal adopts a fully differential method to ensure the signal's anti-interference capability.

[0150] In this application, the data processing unit further includes a data buffer module, used to buffer the voltage / current traveling wave signal after analog-to-digital conversion into at least two designated buffer areas after serial-to-parallel conversion. The module performs alternating read / write control on the voltage / current traveling wave signal buffered in the at least two designated buffer areas, so that when new data is written to one buffer area, the other buffer area can be read. The data buffer module alternately buffers the voltage / current traveling wave signal after analog-to-digital conversion into at least two buffer areas. For example, the received traveling wave signal can be alternately buffered into two different buffer modules. Thus, when data is read from one buffer module, data is written to the other buffer module, and the data reading and writing alternate, ensuring that data reading and writing do not interfere with each other. In this application, the data processing unit is implemented based on an FPGA (Field-Programmable Gate Array), and the buffer module can be SDRAM (Synchronous Dynamic Random Access Memory). The data processing unit reads the fault traveling wave data cached in SDRAM, performs phase mode transformation, and then extracts fault feature information through wavelet mode maxima detection. This extracted fault feature information is then sent to the ranging calculation unit, which can be an MCU. The MCU performs single-ended and / or double-ended ranging calculations, fault detection, and other operations. The clock data required for the MCU's calculations is obtained from the BeiDou module. The MCU can send the calculated time point, fault distance, fault type, and other data to the FTU, which then uploads the data to the master station for policy judgment.

[0151] This application integrates a traveling wave transformer with a pole-mounted switch, and connects the traveling wave signal processing part as a module to the FTU. It relies on the existing FTU and the distribution automation master station for communication. Using this method to locate fault points and identify fault types can effectively reduce construction costs and reduce the difficulty of construction and modification.

[0152] like Figure 2As shown, the data processing unit further includes a high-speed acquisition module, used to send control signals and clock signals to the signal conversion unit to acquire data from the voltage / current traveling wave signals from the signal conversion unit, and to convert the serial differential signals from the signal conversion unit into parallel multi-bit data. The high-speed acquisition module includes an AD controller and a serial-to-parallel converter. The AD controller sends control signals and clock signals to the AD sampling chip to acquire data from each channel of the AD sampling chip. Simultaneously, since the data output format of the AD sampling chip is serial, a serial-to-parallel converter is used to convert the serial data to parallel data to improve the data stream processing speed. This resource-intensive approach achieves a higher data throughput, thereby increasing the data processing speed.

[0153] The data buffer module includes an input asynchronous buffer, an output asynchronous buffer, a first random access memory (RAM), a second random access memory (RAM), and a buffer controller. The input asynchronous buffer is used to buffer voltage / current traveling wave signals from the high-speed acquisition module. The buffer controller is used to sequentially read voltage / current traveling wave signals from the input asynchronous buffer and alternately store the read voltage / current traveling wave signals into the first RAM and the second RAM, and alternately read voltage / current traveling wave signals from the first RAM and the second RAM and sequentially store the read voltage / current traveling wave signals into the output asynchronous buffer.

[0154] The buffer controller is a ping-pong buffer controller. Because the clock frequency of the high-speed acquisition section differs from the clock frequency of the storage and processing sections, the data acquired from each channel must be buffered through an asynchronous FIFO (First Input First Output). In this application, both the input and output asynchronous buffers are FIFO buffers. Since the traveling wave signal data volume for fault location is very large, this application uses two SDRAM chips in a ping-pong buffer configuration to continuously and uninterruptedly acquire the traveling wave signal on the line, avoiding data loss. The traveling wave signal data acquired from the AD sampling chip is buffered from the input FIFO to the storage module SDRAM1 or SDRAM2 through the ping-pong buffer controller, and simultaneously, data is read from the other SDRAM chip and written to the output FIFO. For example, alternately storing the read voltage / current traveling wave signals into a first random access memory (RAM) and a second RAM can include: numbering the acquired traveling wave signals; determining the number of the read voltage / current traveling wave signal during reading; if the current voltage / current traveling wave signal number is odd, storing the current voltage / current traveling wave signal into the first RAM; if the current voltage / current traveling wave signal number is even, storing the current voltage / current traveling wave signal into the second RAM; alternately reading the voltage / current traveling wave signals from the first RAM and the second RAM includes: performing a write operation on the first RAM while simultaneously performing a read operation on the second RAM; or performing a write operation on the second RAM while simultaneously performing a read operation on the first RAM. This continuous alternation ensures that data reading and writing do not interfere with each other, and that the traveling wave signal data enters and exits in the correct order, allowing the traveling wave signal data to be transmitted to subsequent processing modules without interruption. It is understood that the data processing unit of this application also includes an SDRAM controller, such as an SDRAM1 controller and an SDRAM2 controller. The function of the SDRAM controller is to perform operations such as configuration, precharging, refreshing, reading and writing of the SDRAM, which is not limited here.

[0155] In this application, the data processing unit further includes a signal processing module. Specifically, the signal processing module includes: a phase-mode transformation module, used to sequentially perform phase-mode transformation on the voltage / current traveling wave signals read from the output asynchronous buffer based on the Kelvin transform matrix to extract the line-mode components of each voltage / current traveling wave signal; and a wavelet analysis module, used to extract fault feature information from the extracted line-mode components. The function of the phase-mode transformation module is to convert phasor signals into modulus signals using phase-mode transformation, in order to remove the electromagnetic coupling effects between the three phases. Specifically, such as... Figure 3As shown, this application uses a Karrenbauer transformation matrix to implement the phase mode transformation, where X A X B X C X is the phase component of the voltage or current before the transformation. α X β X γ These are the transformed linear modulus components.

[0156] The wavelet analysis module utilizes the ability of wavelet transform to characterize local signal features in both the time and frequency domains, enabling the detection of singular and abrupt signals, and analyzes transient voltages and currents. For example, when a line fault occurs, wavelet coefficients will exhibit modulus maxima. This application can detect the time and location of the abrupt change by detecting these modulus maxima, thereby achieving fault location. This application utilizes a general-purpose FIR filter IP core provided by the FPGA. By importing wavelet coefficients into the FIR filter (Finite Impulse Response Filter), and setting the number of bits and sign of the input signal, the required wavelet filter can be constructed. After the traveling wave signal undergoes wavelet high-pass filtering, the wavelet analysis module further searches and calculates the modulus maxima and determines the polarity of the data to extract fault feature information. The fault analysis module uses a preset fault analysis algorithm to perform fault detection based on the extracted fault feature information, thereby obtaining the fault detection result and generating a corresponding fault detection result signal, fault_code. For example, the fault detection result signal can represent different fault categories using different values.

[0157] In this application, the data processing unit also includes a clock module. The clock module uses a phase-locked loop to multiply the external 50MHz crystal oscillator to the clock required by each module. For example, the clock of the high-speed acquisition module is 50MHz, the clock of the data buffer module is 100MHz, the clock of the signal processing module is 50MHz, and the clock of the fault analysis module is 50MHz.

[0158] In this application, the wavelet analysis module extracts fault feature information from the extracted line mode components, including: decomposing the extracted line mode components based on wavelet transform to obtain the corresponding wavelet transform coefficients; calling a preset modulus maxima search algorithm to search for modulus maxima on all obtained wavelet transform coefficients; if the modulus maxima search algorithm determines that a target modulus maxima representing a line fault exists, a first detection signal representing the detection of the target modulus maxima is generated, and the generated first detection signal is sent to the ranging calculation unit. It is understood that wavelet transform is existing technology, and its transformation process will not be elaborated here.

[0159] Among them, such as Figure 4As shown, the calculation of the modulus maxima is divided into two stages: initial traveling wave detection and reflected wave detection. Each stage defines an initial traveling wave threshold and an initial traveling wave modulus maxima. Then, the modulus maxima search algorithm is called. After the modulus maxima is detected, the modulus maxima, polarity, and channel information are stored. The channel information is used to indicate whether the current detected signal is A-phase current or B-phase voltage, etc.

[0160] like Figure 5 As shown, the modulus maxima search algorithm in the initial traveling wave detection and reflected wave detection stages includes:

[0161] S1. Determine the wavelet coefficient threshold and initial modulus maxima. The wavelet coefficient threshold THRES and initial modulus maxima mod_max can be determined based on actual conditions. Threshold comparison can effectively reduce computational load and the impact of noise. Using wavelet coefficient Xn(i) as input, read the threshold and initial modulus maxima, where X represents the voltage or current signal, n represents channel information (e.g., ia, ib, ic or ua, ub, uc), and i indicates that the current wavelet coefficient is the i-th one.

[0162] S2. Obtain the wavelet transform coefficients. Compare the current wavelet transform coefficients with the wavelet coefficient threshold. If the absolute value of the current wavelet transform coefficients is greater than the wavelet coefficient threshold, proceed to step S3; otherwise, proceed to step S2.

[0163] S3. Compare the current wavelet transform coefficients with the initial modulus maxima. If the current wavelet transform coefficients are greater than the initial modulus maxima, update the current initial modulus maxima with the absolute value of the current wavelet coefficients, that is, let mod_max = |Xn(i)| and execute step S4; otherwise, execute step S5.

[0164] S4. Set the modulus maximum value flag to the first identifier, for example, let the first identifier be flag=1, and determine whether the current search count n is greater than the preset search count threshold N. If it is greater, execute step S6; otherwise, execute step S2.

[0165] S5. Determine whether the current maximum value flag has been set to the first flag. If yes, let the current search count n = n + 1. Determine whether the current search count is greater than the search count threshold. If it is greater, execute step S6. Otherwise, execute step S2.

[0166] S6. Using the current initial modulus maximum as the target modulus maximum, store the searched modulus maximum and generate a first detection signal wave_flag representing the detection of the target modulus maximum. The first detection signal can be a first level signal for M consecutive cycles, such as a high level signal.

[0167] In step S3, after updating the current initial modulus maxima with the absolute value of the current wavelet coefficients, the modulus maxima search algorithm further includes: determining whether the value of the current wavelet transform coefficient is greater than zero; if the value of the current wavelet transform coefficient is greater than zero, determining that the polarity of the current wavelet coefficient is positive, and setting the polarity ploar = 1; if the value of the current wavelet transform coefficient is less than or equal to zero, determining that the polarity of the current wavelet coefficient is negative, and setting the polarity ploar = 0. Then, in step S6, after generating the first detection signal representing the detection of the target modulus maxima, the wavelet analysis module is further used to: generate a second detection signal representing whether the target modulus maxima is positive or negative, and the wavelet analysis module simultaneously sends the generated second detection signal to the ranging calculation unit.

[0168] The generation of a second detection signal characterizing whether the target modulus maximum is positive or negative includes: if the polarity of the target modulus maximum is determined to be positive, outputting a first level signal for multiple consecutive cycles, for example, outputting a high level signal for M cycles; if the polarity of the target modulus maximum is determined to be negative, outputting a second level signal for multiple consecutive cycles, for example, outputting a low level signal for M cycles.

[0169] This application searches for the modulus maxima in a loop. After each search round, the polarity is determined based on the sign of Xn(i). After the entire search process is completed, the value of the modulus maxima register is stored. The wave_flag signal outputs a high level for M consecutive cycles, and the ploar_flag signal determines whether to output a high level for M consecutive cycles based on the value of polar.

[0170] In this application, the fault analysis module performs fault detection based on the extracted fault feature information to obtain fault detection results, including: for each voltage / current traveling wave signal with extracted fault feature information, comparing the extracted line mode components, and determining the fault detection result based on the comparison results of each line mode component. The line mode components of each voltage / current traveling wave signal include: a first line mode component corresponding to the A-phase voltage / current of the voltage / current traveling wave signal, a second line mode component corresponding to the B-phase voltage / current of the voltage / current traveling wave signal, and a third line mode component corresponding to the C-phase voltage / current of the voltage / current traveling wave signal. For example, the first line mode component is represented by α, the second line mode component by β, and the third line mode component by γ.

[0171] Among them, such as Figure 6 As shown, the fault detection results are determined based on the comparison results of each linear modulus component, including:

[0172] S10. If the absolute values ​​of any two of the extracted first, second, and third line-mode components are equal, and the value of the remaining component is zero, the fault detection result is determined to be a single-phase ground fault. For example, taking the current line-mode component as an example, if |Iα|=|Iβ| and Iγ=0, the fault detection result is determined to be a phase A ground fault; if |Iα|=|Iγ| and Iβ=0, the fault detection result is determined to be a phase B ground fault; and if |Iβ|=|Iγ| and Iα=0, the fault detection result is determined to be a phase C ground fault.

[0173] S12. If the absolute value of any one of the extracted first, second, and third line-mode components is greater than the absolute values ​​of the other two, the fault detection result is determined to be a two-phase-to-ground short-circuit fault. For example, if |Iα|>|Iγ| and |Iα|>|Iβ|, the fault detection result is determined to be an AB two-phase-to-ground short-circuit fault; if |Iγ|>|Iα| and |Iγ|>|Iβ|, the fault detection result is determined to be a BC two-phase-to-ground short-circuit fault; if |Iβ|>|Iγ| and |Iβ|>|Iα|, the fault detection result is determined to be an AC two-phase-to-ground short-circuit fault.

[0174] S13. If the absolute value of any one of the extracted first, second, and third linear mode components is equal to twice the absolute value of the other two, the fault detection result is determined to be a two-phase short-circuit fault. For example, if |Iα|=2|Iβ|=2|Iγ|, the fault detection result is determined to be a two-phase short-circuit fault between phases AB; if |Iβ|=2|Iα|=2|Iγ|, the fault detection result is determined to be a two-phase short-circuit fault between phases CA; and if |Iγ|=2|Iα|=2|Iβ|, the fault detection result is determined to be a two-phase short-circuit fault between phases BC.

[0175] S14. If the absolute values ​​of the extracted first, second, and third line-mode components are all greater than zero, and the absolute values ​​of the extracted first, second, and third line-mode components are all different, the fault detection result is determined to be a three-phase ground fault. For example, if |Iα|>0 and |Iβ|>0 and |Iγ|>0, and |Iα|≠|Iβ|≠|Iγ|, the fault detection result is determined to be a three-phase ground fault.

[0176] In this application, the ranging calculation unit is further configured to: determine a first time when the first detection signal is first received, and, if the first detection signal is received again within a first interval, determine a second time when the first detection signal is received again, and determine the time difference between the first time and the second time. Specifically, as shown... Figure 7As shown, the MCU running program of the ranging calculation unit of this application includes three parts: a ranging calculation module, a clock processing module, and a communication processing module. The ranging calculation module receives the wave_flag signal and the ploar_flag signal generated by the FPGA. To ensure the real-time performance of the data calculation, the MCU of the ranging calculation unit of this application has a main frequency of 200MHz or higher and uses an external interrupt to detect the wave_flag signal. When the wave_flag is detected for the first time, the time t1 and the polarity ploar1 are recorded. If the wave_flag signal is detected again after a time interval T1, the time t2 and the polarity ploar2 are recorded, and then the single-end ranging calculation is performed, and the current round of calculation ends. If the wave_flag is not detected again after time T2, the current round of calculation ends.

[0177] The process of determining the first fault location information based on the received first detection signal includes: acquiring the second detection signal corresponding to the first detection signal received for the first time, and acquiring the second detection signal corresponding to the first detection signal received again, i.e., acquiring the polarity information of the modulus maxima extracted from the initial traveling wave and the transmitted wave; and calling the corresponding single-end ranging algorithm to determine the first fault location information based on the comparison result between the first received second detection signal and the second received second detection signal, by comparing the polarity of the modulus maxima extracted from the initial traveling wave and the transmitted wave.

[0178] If the polarity represented by the first received second detection signal is the same as that represented by the second received second detection signal, the first fault location information is determined by the following algorithm:

[0179]

[0180] Among them, D single t1 represents the distance from the fault point to the current detection point, v represents the transmission speed of the voltage / current traveling wave signal, t1 represents the first time, and t2 represents the second time.

[0181] If the polarity represented by the first received second detection signal is different from that represented by the second detected signal received subsequently, the first fault location information is determined using the following algorithm:

[0182]

[0183] Among them, D singleThis represents the distance from the fault point to the current detection point; v represents the transmission speed of the voltage / current traveling wave signal; t1 represents the first time; t2 represents the second time; and L represents the distance between the current detection point and the nearest endpoint on the power distribution line where the current detection point is located. This assumes that there are multiple detection points on the power distribution line where the current detection point is located, and there are no other detection points between the current detection point and that endpoint. For example, see... Figure 9 M is the endpoint of the power distribution line where detection point A is located, and L is the distance between A and M. It is understandable that there are multiple pole-mounted switches on the same power distribution line, meaning multiple detection points are typically installed. When one side of the current detection point is the endpoint of the current power distribution line, the location of the fault point can be determined using a single-end ranging algorithm.

[0184] In the ranging calculation unit, the clock processing module provides a stable and accurate clock. The high-precision clock is achieved using the BeiDou time synchronization module. Since BeiDou time synchronization is achieved by aligning at the second, sufficient timekeeping accuracy is required during the second pulse period to achieve a highly stable clock. The clock crystal oscillator is a direct factor affecting timekeeping accuracy. Conventional ranging devices typically use high-stability temperature-compensated crystal oscillators, but these are power-intensive and expensive. This application uses a high-precision temperature-compensated crystal oscillator instead of the existing temperature-compensated crystal oscillator, utilizing the BeiDou module for real-time correction. The ranging deviation introduced by the crystal oscillator error is 20-30 meters, which meets the ranging requirements.

[0185] The clock information consists of two parts: an absolute time scale accurate to the second, including year, month, day, hour, minute, and second; and a microsecond-level clock. The microsecond-level clock is implemented as follows: an internal timer in the MCU counts, and the clock reference is generated by multiplying an external crystal oscillator, for example, to 100MHz. The MCU reads the time from the BeiDou module at regular intervals (e.g., every hour) to eliminate the accumulated error of the second-level clock. The microsecond-level clock value is corrected using the 1PPS signal from the BeiDou module to ensure accuracy. The correction method is as follows: when the 1PPS pulse triggers an external interrupt on the MCU, the timer count is saved and the timer is cleared. The microsecond value at a given moment is then calculated as (current timer count / previous timer count) × 1000000, as shown in the following formula:

[0186]

[0187] Among them, t us Let T be the value in microseconds at a certain moment. now T is the current timer count value. last This is the previous timer count value.

[0188] The communication processing module of the ranging calculation unit is used for data interaction with the master station. This module receives the first traveling wave time (t1) and the single-ended fault distance data (D) calculated by the ranging calculation module. single The system also collects fault codes from the FPGA and uploads these data to the main station for processing.

[0189] A second aspect of this application provides a power distribution terminal, including: a control unit; and the aforementioned power distribution network traveling wave ranging device; wherein the control unit is communicatively connected to the ranging calculation unit of the power distribution network traveling wave ranging device, and is used to receive first time, first fault location information, and fault detection results sent by the ranging calculation unit. It is understood that the power distribution terminal can be based on an existing FTU, with the control unit being the controller of the existing FTU. This application integrates the power distribution network traveling wave ranging device into an existing FTU, which can effectively reduce equipment costs.

[0190] In a third aspect, this application provides a power distribution network fault monitoring system, comprising: a master station; and a plurality of power distribution terminals as described above; wherein the master station is communicatively connected to each power distribution terminal, and is used to receive first time, first fault location information and fault detection results sent by each power distribution terminal, and to determine second fault location information of the fault point based on the received first time or first fault location information.

[0191] like Figure 8 As shown, in a fourth aspect of this application, a method for monitoring faults in a distribution network is provided, applied to the master station of the aforementioned distribution network fault monitoring system. The method includes:

[0192] S100, in response to the first time or first fault location information sent by any power distribution terminal, determine whether any side of the current power distribution terminal is the endpoint of the current power distribution line;

[0193] S210. If any side of the current power distribution terminal is the endpoint of the current power distribution line, determine whether the current power distribution terminal receives the first time or first fault location information sent by the first adjacent power distribution terminal on the current power distribution line within a preset time range.

[0194] S211. If the first time or first fault location information sent by the first adjacent power distribution terminal is received within the preset time range, it is determined that the fault point is located between the current power distribution terminal and the adjacent power distribution terminal, and the dual-end ranging algorithm is called to calculate the second fault location information of the fault point.

[0195] S212. If the first time or first fault location information sent by the first adjacent power distribution terminal is not received within the preset time range, it is determined that the fault point is located between the current power distribution terminal and the endpoint of its corresponding current power distribution line, and the first fault location information is used as the second fault location information.

[0196] S220. If neither side of the current power distribution terminal is an endpoint of the current power distribution line, and the first fault location information sent by the first adjacent power distribution terminal is received within a preset time range, the dual-end ranging algorithm is called to calculate the second fault location information of the fault point.

[0197] In step S100, the master station monitors all ranging devices on the power distribution line. When the master station receives fault data sent by any ranging device within a certain time range T0, that is, when the master station receives the first detection signal of the target modulus maximum value of the traveling wave signal detected by the ranging device, at the first time and / or the first fault location information of the fault point calculated by the ranging device, it determines whether one side of the ranging device is the end point of the power distribution line. It can be understood that in this application, the ranging device is integrated into the power distribution terminal, and judging the ranging device is judging the corresponding power distribution terminal.

[0198] The determination of whether any side of the current distribution terminal is an endpoint of the current distribution line includes: if there are no other distribution terminals between the current distribution terminal and any endpoint of the current distribution line it is located on, then the corresponding side of the current distribution terminal is determined to be an endpoint of the current distribution line; otherwise, the corresponding side of the current distribution terminal is determined not to be an endpoint of the current distribution line. For example, on distribution line A where distribution terminal A is located, the first endpoint of distribution line A is endpoint 1, and the second endpoint of distribution line A is endpoint 2. Then, if there are no other distribution terminals between distribution terminal A and endpoint 1 of distribution line A, then the first side of distribution terminal A is determined to be an endpoint of distribution line A; or, if there are no other distribution terminals between distribution terminal A and endpoint 2 of distribution line A, then the second side of distribution terminal A is determined to be an endpoint of distribution line A.

[0199] In step S210, after determining that the current power distribution terminal, i.e., one side of the current ranging device, is the end point of the power distribution line, it is determined whether fault data of the ranging device adjacent to the current ranging device is detected within a preset time range, such as within the time range T0.

[0200] like Figure 9 As shown, the fault location strategy of this application is illustrated using a typical T-connection of a branch line in a distribution network as an example. See also... Figure 9M, N, and P are the three endpoints of the power distribution line, and A, B, and C represent sectionalizing switches or branch switches. FTUs are installed on A, B, and C. For existing traditional two-end ranging methods, the ranging device needs to be installed at endpoints M, N, and P. This application installs the ranging device at A, B, and C (the switch locations) and integrates or connects it with the FTU, thereby reducing redundant equipment investment and construction difficulty. Combined with the fault location strategy of the master station, accurate fault location can be achieved. The overall topology of the power distribution line and the distance from each endpoint to each switch are predetermined. Since traveling waves undergo refraction and reflection when they reach the connection points of the line, and the traveling wave modulus maximum is filtered using the threshold THRES, it can be considered that fault traveling waves cannot propagate across switches. Therefore, when a line fault occurs, the master station receives fault data sent by FTUs on lines adjacent to the fault point. F1, F2, and F3 are the fault points of three different line fault locations.

[0201] In step S211, if, after receiving fault data from the current ranging device, fault data is received from a ranging device adjacent to the current ranging device within the time range T0, then the fault point is determined to be located between the current ranging device and the adjacent ranging device. For example, if, after receiving fault data from the ranging device at point A, fault data is received from the ranging devices at points B and C within the time range T0, then the fault point can be determined to be between points A and B, or between points A and C. At this time, the dual-end ranging algorithm is invoked to calculate the fault point location information.

[0202] The dual-end ranging algorithm includes: obtaining the distance between the current distribution terminal and the first adjacent distribution terminal, for example, using... Figure 9 If the distribution terminal at point A is the current distribution terminal, then the distance between point A and point B, and the transmission speed of the voltage / current traveling wave signal are obtained. Based on the distance between the current distribution terminal and the first adjacent distribution terminal, the transmission speed of the voltage / current traveling wave signal, the first time from the current distribution terminal, and the first time from the first adjacent distribution terminal, a first distance between the current distribution terminal and the fault point is calculated using a preset first ranging model, and a second distance between the first adjacent distribution terminal and the fault point is also calculated. If there are no other branch distribution lines between the current distribution terminal and the first adjacent distribution terminal, the second fault location information of the fault point is determined based on the first distance or the second distance. Figure 9 For example, if there is no branch line OP between the power distribution lines MN, the location of the fault point can be determined based on the calculated first or second distance.

[0203] The first ranging model includes:

[0204]

[0205] Among them, D AF D represents the first distance between the current power distribution terminal and the fault point. BF The second distance between the first adjacent distribution terminal and the fault point is given by T, where v is the transmission speed of the voltage / current traveling wave signal, and T is the distance between the first adjacent distribution terminal and the fault point. FA For the first time from the current power distribution terminal, T FB For the first time from the first adjacent distribution terminal, L AB This is the distance between the current power distribution terminal and the first adjacent power distribution terminal.

[0206] In this application, if there are other branch power lines between the current power distribution terminal and the first adjacent power distribution terminal, the dual-end ranging algorithm further includes: obtaining a third distance between the current power distribution terminal and the corresponding branch power line at the branch connection point on the current power distribution line, for example, using... Figure 9 If the distribution terminal at point A is the current distribution terminal, then obtain the distance from point A to point O, and obtain the second adjacent distribution terminal on the corresponding branch line that is closest to the branch connection point, such as the first time the distribution terminal at point C sends, and the fourth distance between the second adjacent distribution terminal and the branch connection point, such as the distance from point C to point O; if the first distance and the third distance are different, for example, ... Figure 9 In the middle, L AF ≠L AO Then it can be determined that the fault point is between A and B. Based on the first distance or the second distance, the second fault location information of the fault point is determined, and L is solved. AF or L BF The fault point F1 can be located; if the first distance and the third distance are the same, i.e., L AF =L AO Then it can be determined that the fault point is on the branch line with connection point O in AB. Based on the third distance, the fourth distance, the transmission speed of the voltage / current traveling wave signal, the first time from the current power distribution terminal and the first time from the second adjacent power distribution terminal, the fifth distance between the current power distribution terminal and the fault point, and the sixth distance between the second adjacent power distribution terminal and the fault point are calculated through the preset second ranging model. The second fault location information of fault point F3 can be determined based on the fifth distance or the sixth distance.

[0207] Specifically, the second ranging model includes:

[0208]

[0209] Among them, D AF D represents the fifth distance between the current power distribution terminal and the fault point. CF The distance between the second adjacent distribution terminal and the fault point is the sixth distance, v is the transmission speed of the voltage / current traveling wave signal, and T is the distance between the second adjacent distribution terminal and the fault point. FA For the first time from the current power distribution terminal, TFC For the first time from the second adjacent distribution terminal, L AO L represents the third distance between the current distribution terminal and the branch connection point. CO The fourth distance is the distance between the second adjacent distribution terminal and the branch connection point.

[0210] In step S212, if one side of the current power distribution terminal is an endpoint of a power distribution line, for example, Figure 9 If, after receiving fault data sent by the power distribution terminal at point A, no fault data is received from other power distribution terminals within T0, then the fault point can be determined to be between the current power distribution terminal and the endpoint of its corresponding current power distribution line, i.e., fault point F2, located between point A and endpoint M. In this case, the location of the fault point is directly sampled using the single-end ranging algorithm. Since the first fault location information received is calculated by the ranging device using the single-end ranging algorithm, this result can be directly sampled.

[0211] In step S220, if neither side of the current power distribution terminal is an endpoint of the current power distribution line, then the fault point detected by the current power distribution terminal must be located between the current power distribution terminal and the adjacent power distribution terminal. In this case, the dual-end ranging algorithm can be directly called and the calculation can be performed according to the calculation process in step S211.

[0212] Understandably, in this application, voltage and current traveling wave signals can be acquired simultaneously. Since current and voltage traveling waves have the same speed of movement on the same line, the fault distance can be accurately measured by utilizing the current and voltage traveling waves at both ends of the line. Specifically, the signal selection method for fault location in this application includes: for the bus end of the faulty line, where the distribution system typically has many outgoing lines, the initial current traveling wave amplitude at the bus measurement end is large, while the initial voltage traveling wave amplitude is small; therefore, the current traveling wave is used as the location signal. For the end of the line supplying power to users and enterprises, due to the presence of a load transformer, the AC impedance of the high-frequency traveling wave signal is very large, approximating an open circuit state. At this time, the initial current traveling wave at the end of the line is almost zero, while the initial voltage traveling wave is close to twice the incident wave; therefore, the voltage traveling wave is used as the location signal. For the middle section of the line, both current and voltage traveling wave signals are used, and the one with the best signal quality is selected as the location signal.

[0213] like Figure 10 As shown, in a fifth aspect of this application, a power distribution network fault monitoring device is provided, which applies the above-described power distribution network fault monitoring method. The device includes:

[0214] The information receiving module is configured to respond to the first time or first fault location information sent by any power distribution terminal and determine whether any side of the current power distribution terminal is the endpoint of the current power distribution line.

[0215] The judgment module is configured to determine whether, within a preset time range, it receives first time or first fault location information sent by the first adjacent power distribution terminal on the current power distribution line if either side of the current power distribution terminal is the endpoint of the current power distribution line.

[0216] The ranging calculation module is configured to, if it receives first time or first fault location information sent by the first adjacent power distribution terminal within a preset time range, determine that the fault point is located between the current power distribution terminal and the adjacent power distribution terminal, and call the dual-end ranging algorithm to calculate the second fault location information of the fault point;

[0217] If no first time or first fault location information is received from the first adjacent power distribution terminal within a preset time range, it is determined that the fault point is located between the current power distribution terminal and the endpoints of its corresponding current power distribution line, and the first fault location information is used as the second fault location information; and

[0218] If neither side of the current power distribution terminal is an endpoint of the current power distribution line, and the first fault location information sent by the first adjacent power distribution terminal is received within a preset time range, the dual-end ranging algorithm is invoked to calculate the second fault location information of the fault point.

[0219] Optionally, determining whether any side of the current power distribution terminal is an endpoint of the current power distribution line includes:

[0220] If there are no other distribution terminals between the current distribution terminal and any endpoint of the current distribution line it is located on, then the corresponding side of the current distribution terminal is determined to be the endpoint of the current distribution line; otherwise, the corresponding side of the current distribution terminal is determined not to be the endpoint of the current distribution line.

[0221] Optionally, the two-end ranging algorithm includes:

[0222] Obtain the distance between the current power distribution terminal and the first adjacent power distribution terminal, and obtain the transmission speed of the voltage / current traveling wave signal;

[0223] Based on the distance between the current power distribution terminal and the first adjacent power distribution terminal, the transmission speed of the voltage / current traveling wave signal, the first time from the current power distribution terminal and the first time from the first adjacent power distribution terminal, the first distance between the current power distribution terminal and the fault point is calculated through a preset first ranging model, and the second distance between the first adjacent power distribution terminal and the fault point is calculated.

[0224] If there are no other branch power lines between the current power distribution terminal and the first adjacent power distribution terminal, the second fault location information of the fault point is determined based on the first distance or the second distance.

[0225] Optionally, the two-end ranging algorithm also includes:

[0226] If there are other branch distribution lines between the current distribution terminal and the first adjacent distribution terminal, obtain the third distance between the current distribution terminal and the branch connection point of the corresponding branch distribution line on the current distribution line, and obtain the first time sent by the second adjacent distribution terminal closest to the branch connection point on the corresponding branch distribution line, and the fourth distance between the second adjacent distribution terminal and the branch connection point.

[0227] If the first distance and the third distance are different, determine the second fault location information based on the first distance or the second distance;

[0228] If the first distance is the same as the third distance, based on the third distance, the fourth distance, the transmission speed of the voltage / current traveling wave signal, the first time from the current power distribution terminal and the first time from the second adjacent power distribution terminal, the fifth distance between the current power distribution terminal and the fault point, and the sixth distance between the second adjacent power distribution terminal and the fault point are calculated by the preset second ranging model.

[0229] Second fault location information is determined based on the fifth or sixth distance.

[0230] Optionally, the first ranging model includes:

[0231]

[0232] Among them, D AF D represents the first distance between the current power distribution terminal and the fault point. BF The second distance between the first adjacent distribution terminal and the fault point is given by T, where v is the transmission speed of the voltage / current traveling wave signal, and T is the distance between the first adjacent distribution terminal and the fault point. FA For the first time from the current power distribution terminal, T FB For the first time from the first adjacent distribution terminal, L AB This is the distance between the current power distribution terminal and the first adjacent power distribution terminal.

[0233] Optionally, the second ranging model includes:

[0234]

[0235] Among them, D AF D represents the fifth distance between the current power distribution terminal and the fault point. CF The distance between the second adjacent distribution terminal and the fault point is the sixth distance, v is the transmission speed of the voltage / current traveling wave signal, and T is the distance between the second adjacent distribution terminal and the fault point. FA For the first time from the current power distribution terminal, T FC For the first time from the second adjacent distribution terminal, L AO L represents the third distance between the current distribution terminal and the branch connection point. CO The fourth distance is the distance between the second adjacent distribution terminal and the branch connection point.

[0236] It is understood that those skilled in the art will clearly recognize that, for the sake of convenience and brevity, the above-described division of functional units and modules is used as an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the device 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 embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. Furthermore, the specific names of the functional units and modules are only for easy differentiation and are not intended to limit the scope of protection of this application. The specific working process of the units and modules in the above system can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0237] In a sixth aspect, this application provides a machine-readable storage medium storing instructions that, when executed by a processor, configure the processor to perform the power distribution network fault monitoring method described above.

[0238] In a seventh aspect, this application provides a terminal device including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the power distribution network fault monitoring method described above.

[0239] like Figure 11 The diagram shown is a schematic representation of a terminal device provided in an embodiment of this application. Figure 11 As shown, the terminal device 10 of this embodiment includes a processor 100, a memory 101, and a computer program 102 stored in the memory 101 and executable on the processor 100. When the processor 100 executes the computer program 102, it implements the steps in the above method embodiments. Alternatively, when the processor 100 executes the computer program 102, it implements the functions of each module / unit in the above device embodiments.

[0240] For example, computer program 102 may be divided into one or more modules / units, one or more of which are stored in memory 101 and executed by processor 100 to complete this application. One or more modules / units may be a series of computer program instruction segments capable of performing a specific function, which describe the execution process of computer program 102 in terminal device 10.

[0241] Terminal device 10 may be a computing device such as a desktop computer, laptop, handheld computer, or cloud server. Terminal device 10 may include, but is not limited to, a processor 100 and a memory 101. Those skilled in the art will understand that... Figure 11 This is merely an example of terminal device 10 and does not constitute a limitation on terminal device 10. It may include more or fewer components than shown, or combine certain components, or different components. For example, terminal device may also include input / output devices, network access devices, buses, etc.

[0242] The processor 100 can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor or any conventional processor.

[0243] The memory 101 can be an internal storage unit of the terminal device 10, such as a hard disk or RAM of the terminal device 10. The memory 101 can also be an external storage device of the terminal device 10, such as a plug-in hard disk, Smart Media Card (SMC), Secure Digital (SD) card, or Flash Card equipped on the terminal device 10. Furthermore, the memory 101 can include both internal and external storage units of the terminal device 10. The memory 101 is used to store computer programs and other programs and data required by the terminal device 10. The memory 101 can also be used to temporarily store data that has been output or will be output.

[0244] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0245] In summary, traditional two-end traveling wave ranging devices require significant investment and are difficult to install and modify in distribution networks due to the numerous branches. The device described in this application can be directly installed in a distribution terminal unit (FTU), communicating with the master station via the FTU. It simultaneously performs single-end and two-end ranging calculations, and the results from both methods are uploaded to the master station. The master station then uses appropriate strategies to locate the fault point. Compared to traditional two-end ranging methods, this reduces the number of ranging devices required, significantly lowering investment and construction costs while reducing the difficulty of installation and modification. Furthermore, since the FTU is not necessarily located at the end of the line, this application effectively solves the problem of measurement blind spots. In addition, this application… The fault location device is developed based on FPGA, realizing high-speed sampling and processing of traveling wave data. By analyzing the data before and after the fault through wavelet transform, the signal abrupt change point is identified, thereby accurately capturing the traveling wave front. This effectively solves the problems of low location accuracy, missed detection, and incorrect detection that often occur in distribution networks with small power supply radius and weak fault signals. At the same time, this application performs fault type analysis based on the amplitude and polarity characteristics of the fault waveform. The fault location device can achieve rapid fault analysis without increasing additional costs. It can also upload fault codes to the main station, providing a reference basis for the diagnosis of distribution network faults.

[0246] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0247] The above are merely embodiments of this application and are not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A traveling wave ranging device for power distribution networks, characterized in that, include: The current transformer installed on the corresponding pole-mounted switch pole is used to collect the voltage / current traveling wave signal at the corresponding detection point; The data processing unit includes: A phase-mode conversion module is used to perform phase-mode conversion on the voltage / current traveling wave signals to extract the line-mode components of each voltage / current traveling wave signal; The wavelet analysis module is used to decompose the extracted line mode components based on wavelet transform to obtain the corresponding wavelet transform coefficients. It calls a preset modulus maxima search algorithm to search for modulus maxima of all obtained wavelet transform coefficients. If the modulus maxima search algorithm determines that there is a target modulus maxima representing a line fault, a first detection signal is generated. The first detection signal represents that the target modulus maxima has been detected. The fault analysis module is used to compare the extracted line mode components for each voltage / current traveling wave signal for which fault feature information has been extracted, and to determine the fault detection result based on the comparison results of each line mode component. The ranging calculation unit is used to receive the first detection signal generated by the wavelet analysis module and determine the first fault location information based on the received first detection signal. The line mode components of each voltage / current traveling wave signal include: The first linear mode component corresponding to the A-phase voltage / current of the voltage / current traveling wave signal, the second linear mode component corresponding to the B-phase voltage / current of the voltage / current traveling wave signal, and the third linear mode component corresponding to the C-phase voltage / current of the voltage / current traveling wave signal; The fault detection results are determined based on the comparison results of each linear modulus component, including: If the absolute values ​​of any two of the extracted first line mode component, second line mode component, and third line mode component are equal, and the value of the other one is zero, the fault detection result is determined to be a single-phase ground fault. If the absolute value of any one of the extracted first line mode component, second line mode component, and third line mode component is greater than the absolute values ​​of the other two, the fault detection result is determined to be a two-phase ground short circuit fault. If the absolute value of any one of the extracted first linear mode component, second linear mode component, and third linear mode component is equal to twice the absolute value of the other two, the fault detection result is determined to be a two-phase short circuit fault. If the absolute values ​​of the extracted first, second, and third line-mode components are all greater than zero, and the absolute values ​​of the extracted first, second, and third line-mode components are all different, the fault detection result is determined to be a three-phase ground fault.

2. The power distribution network traveling wave ranging device according to claim 1, characterized in that, The power distribution network traveling wave ranging device also includes: The signal conversion unit is used to perform analog-to-digital conversion on the acquired voltage / current traveling wave signal, wherein the voltage / current traveling wave signal after analog-to-digital conversion is a serial differential signal; The data processing unit further includes a data buffer module, which is used to buffer the voltage / current traveling wave signal after analog-to-digital conversion into at least two designated buffer areas after serial-to-parallel conversion, and to perform alternating read and write control on the voltage / current traveling wave signal buffered in at least two designated buffer areas, so that when new data is written to one buffer area, the other buffer area can be read.

3. The power distribution network traveling wave ranging device according to claim 2, characterized in that, The power distribution network traveling wave ranging device also includes: The signal conditioning unit is used to preprocess the voltage / current traveling wave signal acquired by the transformer, and to send the preprocessed voltage / current traveling wave signal to the signal conversion unit. The preprocessing includes at least amplification and filtering of the voltage / current traveling wave signals acquired by the transformer.

4. The power distribution network traveling wave ranging device according to claim 2, characterized in that, The data processing unit further includes: The high-speed acquisition module is used to send control signals and clock signals to the signal conversion unit to acquire data from the voltage / current traveling wave signal from the signal conversion unit, and to convert the serial differential signal from the signal conversion unit into parallel multi-bit data.

5. The power distribution network traveling wave ranging device according to claim 4, characterized in that, The data caching module includes: An input asynchronous buffer, an output asynchronous buffer, a first random access memory, a second random access memory, and a buffer controller; The input asynchronous buffer is used to buffer the voltage / current traveling wave signal from the high-speed acquisition module; The buffer controller is configured to sequentially read voltage / current traveling wave signals from the input asynchronous buffer and alternately store the read voltage / current traveling wave signals into the first random access memory and the second random access memory, and alternately read voltage / current traveling wave signals from the first random access memory and the second random access memory and sequentially store the read voltage / current traveling wave signals into the output asynchronous buffer.

6. The power distribution network traveling wave ranging device according to claim 5, characterized in that, The read voltage / current traveling wave signals are alternately stored in the first random access memory and the second random access memory, including: Determine the number of the voltage / current traveling wave signal read; If the current voltage / current traveling wave signal number is odd, store the current voltage / current traveling wave signal in the first random access memory; if the current voltage / current traveling wave signal number is even, store the current voltage / current traveling wave signal in the second random access memory.

7. The power distribution network traveling wave ranging device according to claim 6, characterized in that, Alternatingly reading voltage / current traveling wave signals from the first random access memory and the second random access memory includes: When a voltage / current traveling wave signal is written to the first random access memory, a voltage / current traveling wave signal is read from the second random access memory; or When a voltage / current traveling wave signal is written to the second random access memory, a voltage / current traveling wave signal is read from the first random access memory.

8. The power distribution network traveling wave ranging device according to claim 5, characterized in that, The phase mode transformation module is used to perform phase mode transformation on the voltage / current traveling wave signals read from the output asynchronous buffer according to the Kelvin transform matrix in sequence, so as to extract the line mode components of each voltage / current traveling wave signal.

9. The power distribution network traveling wave ranging device according to claim 1, characterized in that, The modulus maximum search algorithm includes: S1. Determine the wavelet coefficient threshold and the initial modulus maxima; S2. Obtain wavelet transform coefficients, compare the current wavelet transform coefficients with the wavelet coefficient threshold, if the absolute value of the current wavelet transform coefficients is greater than the wavelet coefficient threshold, proceed to step S3; otherwise, proceed to step S2. S3. Compare the current wavelet transform coefficients with the initial modulus maxima. If the current wavelet transform coefficients are greater than the initial modulus maxima, update the current initial modulus maxima with the absolute value of the current wavelet coefficients and proceed to step S4. Otherwise, proceed to step S5. S4. Set the modulus maximum value flag to the first flag and determine whether the current search count is greater than the preset search count threshold. If it is greater, proceed to step S6; otherwise, proceed to step S2. S5. Determine whether the current maximum value flag has been set to the first flag. If yes, determine whether the current search count is greater than the search count threshold. If it is greater, execute step S6; otherwise, execute step S2. S6. Using the current initial modulus maximum as the target modulus maximum, generate a first detection signal representing the detection of the target modulus maximum.

10. The power distribution network traveling wave ranging device according to claim 9, characterized in that, After updating the current initial modulus maxima with the absolute values ​​of the current wavelet coefficients, the modulus maxima search algorithm further includes: Determine whether the current wavelet transform coefficient values ​​are greater than zero; If the current wavelet transform coefficient value is greater than zero, the polarity of the current wavelet coefficient is determined to be positive; if the current wavelet transform coefficient value is less than or equal to zero, the polarity of the current wavelet coefficient is determined to be negative.

11. The power distribution network traveling wave ranging device according to claim 10, characterized in that, After generating a first detection signal representing the detection of the target modulus maxima, the wavelet analysis module is further used for: A second detection signal is generated to characterize whether the target modulus maxima is positive or negative, and the generated second detection signal is sent to the ranging calculation unit.

12. The power distribution network traveling wave ranging device according to claim 11, characterized in that, Generating a second detection signal characterizing whether the target modulus maxima is positive or negative includes: If the polarity of the target modulus maximum is determined to be positive, a first-level signal for multiple consecutive cycles is output. If the polarity of the target modulus maximum is determined to be negative, a second-level signal with multiple consecutive cycles is output.

13. The power distribution network traveling wave ranging device according to claim 1, characterized in that, The first detection signal includes: The first level signal for multiple consecutive cycles.

14. The power distribution network traveling wave ranging device according to claim 11, characterized in that, The ranging calculation unit is also used for: When the first detection signal is received for the first time, a first time when the first detection signal is received for the first time is determined, and if the first detection signal is received again within a first interval, a second time when the first detection signal is received again is determined, and the time difference between the first time and the second time is determined. The first fault location information is determined based on the received first detection signal, including: Obtain the second detection signal corresponding to the first detection signal received for the first time, and obtain the second detection signal corresponding to the first detection signal received again; The first fault location information is determined by calling the corresponding single-end ranging algorithm based on the comparison result between the first received second detection signal and the second received second detection signal.

15. The power distribution network traveling wave ranging device according to claim 14, characterized in that, Based on the comparison result between the first received second detection signal and the second received signal, the corresponding single-ended ranging algorithm is invoked to determine the first fault location information, including: If the polarity represented by the first received second detection signal is the same as that represented by the second received second detection signal, the first fault location information is determined by the following algorithm: Among them, D single t1 represents the distance from the fault point to the current detection point, v represents the transmission speed of the voltage / current traveling wave signal, t1 represents the first time, and t2 represents the second time.

16. The power distribution network traveling wave ranging device according to claim 14, characterized in that, Based on the comparison result between the first received second detection signal and the second received signal, the corresponding single-ended ranging algorithm is invoked to determine the first fault location information, including: If the polarity represented by the first received second detection signal is different from that represented by the second detected signal received subsequently, the first fault location information is determined using the following algorithm: Among them, D single The distance from the fault point to the current detection point is represented by v, the transmission speed of the voltage / current traveling wave signal is represented by t1, the first time is represented by t2, the second time is represented by L, and the distance between the current detection point and the nearest endpoint on the power distribution line where the current detection point is located is represented by L. There are multiple detection points on the power distribution line where the current detection point is located, and there are no other detection points between the current detection point and the endpoint.

17. A power distribution terminal, characterized in that, include: Control unit; as well as The power distribution network traveling wave ranging device according to any one of claims 14-16; The control unit is communicatively connected to the ranging calculation unit of the power distribution network traveling wave ranging device, and is used to receive the first time, first fault location information and fault detection results sent by the ranging calculation unit.

18. A power distribution network fault monitoring system, characterized in that, include: Main site; as well as Multiple power distribution terminals as described in claim 17; The master station is communicatively connected to each power distribution terminal and is used to receive the first time, first fault location information and fault detection results sent by each power distribution terminal, as well as the second fault location information to determine the fault point based on the received first time or first fault location information.

19. A method for monitoring faults in a distribution network, applied to the master station of the distribution network fault monitoring system of claim 18, characterized in that, The method includes: In response to the first time or first fault location information sent by any power distribution terminal, determine whether any side of the current power distribution terminal is the endpoint of the current power distribution line; If any side of the current power distribution terminal is the endpoint of the current power distribution line, determine whether the current power distribution terminal receives the first time or first fault location information sent by the first adjacent power distribution terminal on the current power distribution line within a preset time range; If the first time or first fault location information sent by the first adjacent power distribution terminal is received within the preset time range, it is determined that the fault point is located between the current power distribution terminal and the adjacent power distribution terminal, and the dual-end ranging algorithm is called to calculate the second fault location information of the fault point; If the first time or first fault location information sent by the first adjacent power distribution terminal is not received within the preset time range, it is determined that the fault point is located between the current power distribution terminal and the endpoint of its corresponding current power distribution line, and the first fault location information is used as the second fault location information. If neither side of the current power distribution terminal is an endpoint of the current power distribution line, and the first fault location information sent by the first adjacent power distribution terminal is received within the preset time range, the dual-end ranging algorithm is invoked to calculate the second fault location information of the fault point.

20. A method for monitoring faults in a power distribution network according to claim 19, characterized in that, Determining whether either side of the current power distribution terminal is an endpoint of the current power distribution line includes: If there are no other distribution terminals between the current distribution terminal and any endpoint of the current distribution line it is located on, then the corresponding side of the current distribution terminal is determined to be the endpoint of the current distribution line; otherwise, the corresponding side of the current distribution terminal is determined not to be the endpoint of the current distribution line.

21. A method for monitoring faults in a power distribution network according to claim 19, characterized in that, The dual-end ranging algorithm includes: Obtain the distance between the current power distribution terminal and the first adjacent power distribution terminal, and obtain the transmission speed of the voltage / current traveling wave signal; Based on the distance between the current power distribution terminal and the first adjacent power distribution terminal, the transmission speed of the voltage / current traveling wave signal, the first time from the current power distribution terminal and the first time from the first adjacent power distribution terminal, the first distance between the current power distribution terminal and the fault point is calculated through a preset first ranging model, and the second distance between the first adjacent power distribution terminal and the fault point is calculated. If there are no other branch power lines between the current power distribution terminal and the first adjacent power distribution terminal, the second fault location information of the fault point is determined based on the first distance or the second distance.

22. A method for monitoring faults in a power distribution network according to claim 21, characterized in that, The dual-end ranging algorithm further includes: If there are other branch distribution lines between the current distribution terminal and the first adjacent distribution terminal, obtain the third distance between the current distribution terminal and the branch connection point of the corresponding branch distribution line on the current distribution line, and obtain the first time sent by the second adjacent distribution terminal closest to the branch connection point on the corresponding branch distribution line, and the fourth distance between the second adjacent distribution terminal and the branch connection point. If the first distance is different from the third distance, the second fault location information of the fault point is determined based on the first distance or the second distance; If the first distance is the same as the third distance, based on the third distance, the fourth distance, the transmission speed of the voltage / current traveling wave signal, the first time from the current power distribution terminal and the first time from the second adjacent power distribution terminal, the fifth distance between the current power distribution terminal and the fault point, and the sixth distance between the second adjacent power distribution terminal and the fault point are calculated by a preset second ranging model. The second fault location information is determined based on the fifth distance or the sixth distance.

23. A method for monitoring faults in a power distribution network according to claim 21, characterized in that, The first ranging model includes: Among them, D AF D represents the first distance between the current power distribution terminal and the fault point. BF The second distance between the first adjacent distribution terminal and the fault point is given by T, where v is the transmission speed of the voltage / current traveling wave signal, and T is the distance between the first adjacent distribution terminal and the fault point. FA For the first time from the current power distribution terminal, T FB For the first time from the first adjacent power distribution terminal, L AB This is the distance between the current power distribution terminal and the first adjacent power distribution terminal.

24. A method for monitoring faults in a power distribution network according to claim 22, characterized in that, The second ranging model includes: Among them, D AF D represents the fifth distance between the current power distribution terminal and the fault point. CF The distance between the second adjacent distribution terminal and the fault point is the sixth distance, v is the transmission speed of the voltage / current traveling wave signal, and T is the distance between the second adjacent distribution terminal and the fault point. FA For the first time from the current power distribution terminal, T FC For the first time from the second adjacent distribution terminal, L AO L is the third distance between the current power distribution terminal and the branch contact point. CO This is the fourth distance between the second adjacent power distribution terminal and the branch connection point.

25. A power distribution network fault monitoring device, employing the power distribution network fault monitoring method according to any one of claims 19-24, characterized in that, The device includes: The information receiving module is configured to respond to the first time or first fault location information sent by any power distribution terminal and determine whether any side of the current power distribution terminal is the endpoint of the current power distribution line. The judgment module is configured to determine whether, within a preset time range, it receives first time or first fault location information sent by the first adjacent power distribution terminal on the current power distribution line if either side of the current power distribution terminal is the endpoint of the current power distribution line. The ranging calculation module is configured to, if it receives the first time or first fault location information sent by the first adjacent power distribution terminal within the preset time range, determine that the fault point is located between the current power distribution terminal and the adjacent power distribution terminal, and call the dual-end ranging algorithm to calculate the second fault location information of the fault point; If no first time or first fault location information is received from the first adjacent power distribution terminal within the preset time range, it is determined that the fault point is located between the current power distribution terminal and the endpoints of its corresponding current power distribution line, and the first fault location information is used as the second fault location information; and If neither side of the current power distribution terminal is an endpoint of the current power distribution line, and the first fault location information sent by the first adjacent power distribution terminal is received within the preset time range, the dual-end ranging algorithm is invoked to calculate the second fault location information of the fault point.

26. A power distribution network fault monitoring device according to claim 25, characterized in that, Determining whether either side of the current power distribution terminal is an endpoint of the current power distribution line includes: If there are no other distribution terminals between the current distribution terminal and any endpoint of the current distribution line it is located on, then the corresponding side of the current distribution terminal is determined to be the endpoint of the current distribution line; otherwise, the corresponding side of the current distribution terminal is determined not to be the endpoint of the current distribution line.

27. A power distribution network fault monitoring device according to claim 25, characterized in that, The dual-end ranging algorithm includes: Obtain the distance between the current power distribution terminal and the first adjacent power distribution terminal, and obtain the transmission speed of the voltage / current traveling wave signal; Based on the distance between the current power distribution terminal and the first adjacent power distribution terminal, the transmission speed of the voltage / current traveling wave signal, the first time from the current power distribution terminal and the first time from the first adjacent power distribution terminal, the first distance between the current power distribution terminal and the fault point is calculated through a preset first ranging model, and the second distance between the first adjacent power distribution terminal and the fault point is calculated. If there are no other branch power lines between the current power distribution terminal and the first adjacent power distribution terminal, the second fault location information of the fault point is determined based on the first distance or the second distance.

28. A power distribution network fault monitoring device according to claim 27, characterized in that, The dual-end ranging algorithm further includes: If there are other branch distribution lines between the current distribution terminal and the first adjacent distribution terminal, obtain the third distance between the current distribution terminal and the branch connection point of the corresponding branch distribution line on the current distribution line, and obtain the first time sent by the second adjacent distribution terminal closest to the branch connection point on the corresponding branch distribution line, and the fourth distance between the second adjacent distribution terminal and the branch connection point. If the first distance is different from the third distance, the second fault location information of the fault point is determined based on the first distance or the second distance; If the first distance is the same as the third distance, based on the third distance, the fourth distance, the transmission speed of the voltage / current traveling wave signal, the first time from the current power distribution terminal and the first time from the second adjacent power distribution terminal, the fifth distance between the current power distribution terminal and the fault point, and the sixth distance between the second adjacent power distribution terminal and the fault point are calculated by a preset second ranging model. The second fault location information is determined based on the fifth distance or the sixth distance.

29. A power distribution network fault monitoring device according to claim 27, characterized in that, The first ranging model includes: Among them, D AF D represents the first distance between the current power distribution terminal and the fault point. BF The second distance between the first adjacent distribution terminal and the fault point is given by T, where v is the transmission speed of the voltage / current traveling wave signal, and T is the distance between the first adjacent distribution terminal and the fault point. FA For the first time from the current power distribution terminal, T FB For the first time from the first adjacent power distribution terminal, L AB This is the distance between the current power distribution terminal and the first adjacent power distribution terminal.

30. A power distribution network fault monitoring device according to claim 28, characterized in that, The second ranging model includes: Among them, D AF D represents the fifth distance between the current power distribution terminal and the fault point. CF The distance between the second adjacent distribution terminal and the fault point is the sixth distance, v is the transmission speed of the voltage / current traveling wave signal, and T is the distance between the second adjacent distribution terminal and the fault point. FA For the first time from the current power distribution terminal, T FC For the first time from the second adjacent distribution terminal, L AO L is the third distance between the current power distribution terminal and the branch contact point. CO This is the fourth distance between the second adjacent power distribution terminal and the branch connection point.

31. A machine-readable storage medium storing instructions thereon, characterized in that, When executed by a processor, this instruction causes the processor to be configured to perform the power distribution network fault monitoring method as described in any one of claims 19-24.

32. A terminal device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the power distribution network fault monitoring method as described in any one of claims 19-24.

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