Power distribution network traveling wave distance measurement device, power distribution terminal, fault monitoring system and method

Abstract

The invention provides a power distribution network traveling wave distance measurement device, a power distribution terminal and a fault monitoring system and method, and relates to the technical field of power distribution network fault monitoring. The data processing unit comprises a phase-mode conversion module which is used for performing phase-mode conversion on the voltage / current traveling wave signals so as to extract the line-mode component of each voltage / current traveling wave signal; the wavelet analysis module is used for decomposing the extracted line mode component based on wavelet transform to obtain corresponding wavelet transform coefficients, performing mode maximum search on all the obtained wavelet transform coefficients, and generating a first detection signal representing that a target mode maximum is detected if it is determined that the target mode maximum representing the line fault exists; and the distance measurement calculation unit is used for determining first fault position information according to the first detection signal. According to the invention, high-speed sampling and processing of traveling wave data can be realized, and the fault positioning precision of the power distribution network is effectively improved.

Description

Technical Field

[0001] The present application relates to the technical field of distribution network fault monitoring, and specifically to a distribution network traveling wave ranging device, a distribution terminal, a distribution network fault monitoring system, a distribution network fault monitoring method, a distribution network fault monitoring device, a machine-readable storage medium and a terminal device. Background Art

[0002] At present, the existing distribution network fault location usually relies on distribution automation systems, fault indicators and other means. The fault location accuracy is low, and there is still a large line patrol task after the fault, which cannot meet the needs of accurate fault location. In order to meet the purpose of accurate fault location, the traveling wave method is usually used for positioning. Its basic principle is to use distributed monitoring to deconstruct complex distribution network lines into simple lines to achieve high-precision and fast response fault location. Among them, the traveling wave method is divided into single-end ranging method and double-end ranging method. The single-end method detects the time difference between the initial traveling wave and the first reflected wave at the fault point to calculate the fault distance; the double-end method detects the time difference between the traveling wave generated by the fault point and the arrival of the two ends of the line to achieve positioning.

[0003] However, since distribution lines often have overhead lines, cable mixed lines and branch lines, traveling waves undergo complex refraction and reflection during their movement in the distribution lines. It is very difficult to identify these different reflected traveling wave surges at one end of the line. Therefore, it is difficult to accurately determine the location of the fault point using only the single-ended traveling wave fault ranging principle. The double-ended traveling wave fault ranging only needs to accurately detect the time when the initial traveling wave head of the fault arrives at the detection point, without considering the refraction and reflection of subsequent waves. However, due to the large number of distribution network lines, the large number of branches makes it costly and difficult to maintain the subsequent period if the double-ended traveling wave ranging device is to be used in all of them. Summary of the invention

[0004] The purpose of the embodiments of the present application is to provide a distribution network traveling wave ranging device, a distribution terminal, a fault monitoring system and a method to solve the above-mentioned problems.

[0005] In order to achieve the above-mentioned object, the first aspect of the present application provides a distribution network traveling wave ranging device, comprising:

[0006] A mutual inductor arranged on the switch pole on the corresponding column is used to collect the voltage / current traveling wave signal of the corresponding detection point;

[0007] Data processing unit, including:

[0008] A phase mode conversion module, used for performing phase mode conversion on the voltage / current traveling wave signal to extract the line mode component of each voltage / current traveling wave signal;

[0009] Wavelet analysis module, used to extract fault feature information from the extracted line mode components;

[0010] The fault feature information is extracted from the extracted line mode component, including:

[0011] Decomposing the extracted line modulus component based on wavelet transform to obtain corresponding wavelet transform coefficients, calling a preset modulus maximum search algorithm to perform modulus maximum search on all obtained wavelet transform coefficients, and if the modulus maximum search algorithm determines that there is a target modulus maximum representing a line fault, generating a first detection signal representing that the target modulus maximum is detected, wherein the first detection signal represents that the target modulus maximum is detected;

[0012] The distance measurement calculation unit is used to receive the first detection signal generated by the wavelet analysis module, and determine the first fault location information according to the received first detection signal.

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

[0014] A signal conversion unit, used for performing analog-to-digital conversion on the collected 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 also includes a data cache module, which is used to perform serial-to-parallel conversion on the voltage / current traveling wave signal after analog-to-digital conversion and buffer it into at least two designated cache areas, and perform alternating read and write control on the voltage / current traveling wave signal buffered in the at least two designated cache areas, so that when new data is written to one cache area, the other cache area can be read.

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

[0017] A signal conditioning unit, used for preprocessing the voltage / current traveling wave signal collected by the transformer, and sending the preprocessed voltage / current traveling wave signal to the signal conversion unit;

[0018] The preprocessing at least includes amplifying and filtering the voltage / current traveling wave signal collected by the transformer.

[0019] Optionally, the data processing unit includes:

[0020] The high-speed acquisition module is used to send a control signal and a clock signal to the signal conversion unit to perform data acquisition on 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 cache module includes:

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

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

[0024] The cache controller is used to read the voltage / current traveling wave signals from the input asynchronous cache in sequence, and alternately store the read voltage / current traveling wave signals in the first random access memory and the second random access memory, and alternately read the voltage / current traveling wave signals from the first random access memory and the second random access memory, and store the read voltage / current traveling wave signals in sequence in the output asynchronous cache.

[0025] Optionally, alternately storing the read voltage / current traveling wave signal in the first random access memory and the second random access memory includes:

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

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

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

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

[0030] When a write operation of a voltage / current traveling wave signal is performed on the second random access memory, a read operation of a voltage / current traveling wave signal is performed on 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 in sequence based on the Karenberg transformation 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 from which fault characteristic information is extracted, and determine the fault detection result according to the comparison result of each line mode component.

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

[0035] S1, determine the wavelet coefficient threshold and the initial modulus maximum;

[0036] S2, obtaining a wavelet transform coefficient, comparing the current wavelet transform coefficient with the wavelet coefficient threshold, if the absolute value of the current wavelet transform coefficient is greater than the wavelet coefficient threshold, executing step S3, otherwise, executing step S2;

[0037] S3, compare the current wavelet transform coefficient with the initial modulus maximum value, if the current wavelet transform coefficient is greater than the initial modulus maximum value, update the current initial modulus maximum value with the absolute value of the current wavelet coefficient, and execute step S4, otherwise, execute step S5;

[0038] S4, setting the modulus maximum flag bit to the first flag, and determining whether the current search times are greater than a preset search times threshold, if so, executing step S6, otherwise, executing step S2;

[0039] S5, determining whether the current modulus maximum flag has been set to the first flag, if so, determining whether the current search times are greater than the search times threshold, if so, executing step S6, otherwise, executing step S2, otherwise, executing step S2;

[0040] S6. Taking the current initial modulus maximum value as the target modulus maximum value, a first detection signal is generated to indicate that the target modulus maximum value is detected.

[0041] Optionally, after updating the current initial modulus maximum with the absolute value of the current wavelet coefficient, the modulus maximum search algorithm further includes:

[0042] Determine whether the value of the current wavelet transform coefficient is greater than zero;

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

[0044] Optionally, after generating the first detection signal indicating that the target modulus maximum is detected, the wavelet analysis module is further used to:

[0045] A second detection signal is generated to indicate that the target modulus maximum value is positive or negative, and the generated second detection signal is sent to the distance measurement calculation unit.

[0046] Optionally, generating a second detection signal indicating that the target modulus maximum value is positive or negative includes:

[0047] If it is determined that the polarity of the target modulus maximum value is positive, outputting a first level signal for a plurality of consecutive cycles;

[0048] If it is determined that the polarity of the target modulus maximum value is negative, a second level signal is output for a plurality of consecutive cycles.

[0049] Optionally, the first detection signal includes:

[0050] A first level signal with multiple consecutive cycles.

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

[0052] 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;

[0053] The fault detection result is determined based on the comparison results of each line mode component, including:

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

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

[0056] If the absolute value of any one of the extracted first line mode component, the second line mode component and the third line mode component is equal to twice the absolute values ​​of the other two, it is determined that the fault detection result is a two-phase short circuit fault;

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

[0058] Optionally, the distance measurement calculation unit is further used to:

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

[0060] Determining first fault location information according to the received first detection signal includes:

[0061] Acquire a second detection signal corresponding to the first detection signal received for the first time, and acquire a second detection signal corresponding to the first detection signal received again;

[0062] The first fault location information is determined by calling a corresponding single-ended ranging algorithm according to a comparison result of the first received second detection signal and the second received second detection signal.

[0063] Optionally, calling a corresponding single-ended ranging algorithm to determine the first fault location information according to a comparison result of the first received second detection signal and the second received second detection signal includes:

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

[0065]

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

[0067] Optionally, calling a corresponding single-ended ranging algorithm to determine the first fault location information according to a comparison result of the first received second detection signal and the second received second detection signal includes:

[0068] If the polarities represented by the second detection signal received for the first time and the second detection signal received again are different, the first fault location information is determined by the following algorithm:

[0069]

[0070] Among them, D single represents the distance between the fault point and 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 endpoint closest to the current detection point on the distribution line where the current detection point is located, wherein there are multiple detection points set on the 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] In a second aspect of the present application, a power distribution terminal is provided, comprising:

[0072] a control unit; and

[0073] The above-mentioned distribution network travelling wave ranging device;

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

[0075] In a third aspect of the present application, a distribution network fault monitoring system is provided, comprising:

[0076] Master station; and

[0077] A plurality of power distribution terminals as described above;

[0078] The master station is respectively connected to each distribution terminal for receiving the first time, first fault location information and fault detection result sent by each distribution terminal, and determining the second fault location information of the fault point based on the received first time or first fault location information.

[0079] In a fourth aspect of the present application, a distribution network fault monitoring method is provided, which is applied to a master station in the above distribution network fault monitoring system, and the method comprises:

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

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

[0082] If the first time or first fault location information sent by the first adjacent distribution terminal is received within the preset time range, it is determined that the fault point is located between the current distribution terminal and the adjacent distribution terminal, and the two-terminal 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 the current distribution line corresponding to it, and the first fault location information is used as the second fault location information;

[0084] If neither side of the current distribution terminal is an endpoint of the current distribution line, and the first fault location information sent by the first adjacent distribution terminal is received within the preset time range, the two-terminal ranging algorithm is called 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 the endpoint on either side of the current distribution line where it is located, the corresponding side of the current distribution terminal is determined to be the endpoint of the current distribution line; otherwise, it is determined that the corresponding side of the current distribution terminal is not the endpoint of the current distribution line.

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

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

[0089] According to 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 by a preset first distance measurement 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 distribution lines between the current distribution terminal and the first adjacent distribution terminal, second fault location information of the fault point is determined based on the first distance or the second distance.

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

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

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

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

[0095] Second fault location information of the fault point is determined based on the fifth distance or the sixth distance.

[0096] Optionally, the first ranging model includes:

[0097]

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

[0099] Optionally, the second ranging model includes:

[0100]

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

[0102] In a fifth aspect of the present application, a distribution network fault monitoring device is provided, and the distribution network fault monitoring method is applied. The device includes:

[0103] An information receiving module is configured to determine whether any side of the current distribution terminal is an endpoint of the current distribution line in response to the first time or first fault location information sent by any distribution terminal;

[0104] A judgment module is configured to judge whether the first time or first fault location information sent by the first adjacent distribution terminal of the current distribution terminal on the current distribution line is received within a preset time range if any side of the current distribution terminal is an endpoint of the current distribution line;

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

[0106] 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 the current distribution line corresponding to it, and the first fault location information is used as the second fault location information; and

[0107] If neither side of the current distribution terminal is an endpoint of the current distribution line, and the first fault location information sent by the first adjacent distribution terminal is received within the preset time range, the two-terminal ranging algorithm is called 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 the endpoint on either side of the current distribution line where it is located, the corresponding side of the current distribution terminal is determined to be the endpoint of the current distribution line; otherwise, it is determined that the corresponding side of the current distribution terminal is not the endpoint of the current distribution line.

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

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

[0112] According to 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 by a preset first distance measurement 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 distribution lines between the current distribution terminal and the first adjacent distribution terminal, second fault location information of the fault point is determined based on the first distance or the second distance.

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

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

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

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

[0118] Second fault location information of the fault point is determined based on the fifth distance or the sixth distance.

[0119] Optionally, the first ranging model includes:

[0120]

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

[0122] Optionally, the second ranging model includes:

[0123]

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

[0125] In a sixth aspect of the present application, a machine-readable storage medium is provided, on which instructions are stored, and when the instructions are executed by a processor, the processor is configured to execute the distribution network fault monitoring method as described above.

[0126] In a seventh aspect of the present application, a terminal device is provided, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the distribution network fault monitoring method as described above when executing the computer program.

[0127] The distribution network traveling wave ranging device of the present application can be installed in the distribution terminal (FTU), and the traveling wave signal is detected by the mutual inductor set on the pole of the pole switch, and it can communicate with the main station based on the FTU, thereby effectively reducing the investment and construction costs and reducing the difficulty of construction and transformation. At the same time, the device of the present application can realize high-speed sampling and processing of traveling wave data, accurately capture the traveling wave head through phase mode transformation, and effectively improve the accuracy of fault location in the distribution network.

[0128] Other features and advantages of the embodiments of the present application will be described in detail in the subsequent specific implementation section. BRIEF DESCRIPTION OF THE DRAWINGS

[0129] The accompanying drawings are used to provide a further understanding of the embodiments of the present application and constitute a part of the specification. Together with the following specific implementations, they are used to explain the embodiments of the present application, but do not constitute a limitation on the embodiments of the present application. In the accompanying drawings:

[0130] Figure 1 A schematic diagram of the structure of a traveling wave ranging device for a distribution network provided in a preferred embodiment of the present application;

[0131] Figure 2 A schematic diagram of the structure of a data processing unit provided for a preferred embodiment of the present application;

[0132] Figure 3 A schematic diagram of phase mode transformation provided for a preferred embodiment of the present application;

[0133] Figure 4 A flow chart of modulus maximum detection provided for a preferred embodiment of the present application;

[0134] Figure 5 An algorithm flow chart of a modulus maximum value search algorithm provided in a preferred embodiment of the present application;

[0135] Figure 6 A fault detection flow chart provided for a preferred embodiment of the present application;

[0136] Figure 7 A schematic diagram of the structure of a distance measurement calculation unit provided in a preferred embodiment of the present application;

[0137] Figure 8 A strategy determination flow chart provided for a preferred embodiment of the present application;

[0138] Fig. 9A typical wiring diagram of a power distribution network provided for a preferred embodiment of the present application;

[0139] Fig.10 A schematic block diagram of a distribution network fault monitoring device provided in a preferred embodiment of the present application;

[0140] Fig.11 A schematic diagram of a terminal device provided for a preferred embodiment of the present application.

[0141] Description of Reference Numerals

[0142] 10-terminal device, 100-processor, 101-memory, 102-computer program. DETAILED DESCRIPTION

[0143] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. It should be understood that the specific implementation methods described herein are only used to illustrate and explain the embodiments of the present application, and are not used to limit the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0144] It should be noted that the technical solutions between the various embodiments of the present application can be combined with each other, but it must be based on the fact that ordinary technicians in the field can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0145] like Figure 1 As shown, the first aspect of the present application provides a distribution network traveling wave ranging device, including: a mutual inductor arranged on a switch pole on a corresponding pole, for collecting a voltage / current traveling wave signal at a corresponding detection point; a data processing unit, including: a phase mode transformation module, for performing phase mode transformation on the voltage / current traveling wave signal to extract the line mode component of each voltage / current traveling wave signal; a wavelet analysis module, for extracting fault characteristic information from the extracted line mode component; wherein, extracting fault characteristic information from the extracted line mode component includes: decomposing the extracted line mode component based on wavelet transform to obtain corresponding wavelet transform coefficients, calling a preset modulus maximum search algorithm to perform modulus maximum search on all obtained wavelet transform coefficients, and if the modulus maximum search algorithm determines that there is a target modulus maximum value representing a line fault, generating a first detection signal representing the detection of the target modulus maximum value; a ranging calculation unit, for receiving the first detection signal generated by the wavelet analysis module, and determining the first fault location information according to the received first detection signal.

[0146] In this way, the distribution network traveling wave ranging device of the present application can be installed in the distribution terminal (FTU), and the traveling wave signal can be detected by the mutual inductor set on the pole of the pole switch, and it can communicate with the main station based on the FTU, thereby effectively reducing the investment and construction costs and reducing the difficulty of construction and transformation. At the same time, the device of the present application can realize high-speed sampling and processing of traveling wave data, accurately capture the traveling wave head through phase mode transformation, and effectively improve the accuracy of fault location in the distribution network.

[0147] It can be understood that a pole switch refers to a type of safety switch used on a utility pole to ensure the safety of electricity use, and its main function is to isolate the high voltage of the circuit. At present, key nodes of the distribution network, such as trunk line connecting switches, necessary section switches and general nodes, such as branch switches, are equipped with distribution terminals (FTU). The present application places the traveling wave mutual inductor inside or outside the pole of the pole switch, and uses the pole of the pole switch as the detection point to collect the voltage / current traveling wave signal. Among them, the traveling wave ranging device of the present application can be set as an independent device at the corresponding pole switch, such as on the pole corresponding to the pole switch, or the traveling wave ranging device of the present application can be integrated into the original FTU.

[0148] The distribution network traveling wave ranging device of the present application also includes: a signal conversion unit, which is used to perform analog-to-digital conversion on the collected voltage / current traveling wave signal, wherein the voltage / current traveling wave signal after analog-to-digital conversion is a serial differential signal; a signal conditioning unit, which is used to pre-process the voltage / current traveling wave signal collected by the transformer, and send the pre-processed voltage / current traveling wave signal to the signal conversion unit, wherein the pre-processing at least includes amplification and filtering of the voltage / current traveling wave signal collected by the transformer, so as to adjust the small current and small voltage signals on the secondary side of the transformer to the analog signal input range of the signal conversion unit, and denoise the traveling wave signal, so that the sampling data of the signal conversion unit is accurate and the influence of noise on the fault ranging accuracy is eliminated as much as possible. It can be understood that the signal conditioning unit can be implemented using an existing signal conditioning circuit, which is not limited here.

[0149] In the present application, the signal conversion unit is an AD acquisition circuit, for example, an AD converter or an AD sampling chip, and the AD converter converts the pre-processed voltage / current traveling wave signal into a digital signal so that the data processing unit processes the converted voltage / current traveling wave signal. Since the fault transient voltage and current traveling waves on the distribution line are both high-frequency signals, their spectrum is mainly distributed within 10kHz to 100kHz. In order to be able to collect 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 enough response speed. Therefore, the acquisition rate of the A / D converter in the present application is above 5MSPS, and the data bit width is above 12 bits to ensure high positioning accuracy. The input of the traveling wave signal adopts a fully differential method to ensure the anti-interference ability of the signal.

[0150] In the present application, the data processing unit also includes a data cache module, which is used to perform serial-to-parallel conversion on the voltage / current traveling wave signal after analog-to-digital conversion and buffer it to at least two designated cache areas, and perform alternate read and write control on the voltage / current traveling wave signal buffered in at least two designated cache areas, so that when one cache area is writing new data, the other cache area can be read. The data cache module alternately caches the voltage / current traveling wave signal after analog-to-digital conversion into at least two cache areas, for example, alternately caches the received traveling wave signal into two different cache modules, so that when data is read from one of the cache modules, data is written to the other cache module, and the reading and writing of data are performed alternately, thereby ensuring that the reading and writing of data do not affect each other. In the present application, the data processing unit is implemented based on FPGA, that is, field programmable gate array, and the cache module can be SDRAM, that is, synchronous dynamic random access memory. After the data processing unit reads the fault traveling wave data cached in the SDRAM and performs phase mode transformation, it extracts the fault feature information through the detection of the wavelet modulus maximum value, and sends the extracted fault feature information to the ranging calculation unit, wherein the ranging calculation unit can be an MCU, and the MCU performs single-end and / or double-end ranging calculation, fault detection and other operations, wherein the clock data required in the MCU calculation process is obtained by the Beidou module. The MCU can send the calculated time point, fault distance, fault type and other data to the FTU, and then upload the data to the master station through the FTU, so that the master station can make strategic judgments.

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

[0152] like Figure 2As shown, the data processing unit also includes: a high-speed acquisition module, which is used to send a control signal and a clock signal to the signal conversion unit to collect data on the voltage / current traveling wave signal from the signal conversion unit, and convert the serial differential signal from the signal conversion unit into parallel multi-bit data. Among them, the high-speed acquisition module includes an AD controller and a serial-to-parallel converter. The AD controller sends a control signal and a clock signal to the AD sampling chip to collect data from each channel of the AD sampling chip. At the same time, since the data output format of the AD sampling chip is serial, in order to improve the processing speed of the data stream, a serial-to-parallel converter is used to convert serial to parallel, and resources are consumed in exchange for a higher data throughput rate, thereby improving the data processing speed.

[0153] The data cache module includes an input asynchronous cache, an output asynchronous cache, a first random access memory, a second random access memory and a cache controller; the input asynchronous cache is used to cache the voltage / current traveling wave signal from the high-speed acquisition module; the cache controller is used to read the voltage / current traveling wave signal from the input asynchronous cache in sequence, and alternately store the read voltage / current traveling wave signal in the first random access memory and the second random access memory, and alternately read the voltage / current traveling wave signal from the first random access memory and the second random access memory, and store the read voltage / current traveling wave signal in sequence in the output asynchronous cache.

[0154] Among them, the cache controller is a ping-pong cache controller. Since the clock frequency of the high-speed acquisition part is different from the clock frequency of storage and processing, the data collected for each channel must be cached through an asynchronous FIFO (First Input First Output). In this application, the input asynchronous buffer and the output asynchronous buffer are FIFO buffers. Since the amount of traveling wave signal data for fault ranging is very large, this application adopts two SDRAM ping-pong caches to continuously and uninterruptedly collect the traveling wave signal on the line to avoid missing data. The traveling wave signal data collected from the AD sampling chip is buffered in the input FIFO to the storage module SDRAM1 or SDRAM2 through the ping-pong cache controller, and the data in the other SDRAM is read to the output FIFO while writing the data. For example, alternately storing the read voltage / current traveling wave signal to the first random memory and the second random memory may include: numbering the collected traveling wave signal, and determining the number of the read voltage / current traveling wave signal when reading the traveling wave signal; if the number of the current voltage / current traveling wave signal is an odd number, storing the current voltage / current traveling wave signal to the first random memory; if the number of the current voltage / current traveling wave signal is an even number, storing the current voltage / current traveling wave signal to the second random memory; alternately reading the voltage / current traveling wave signal from the first random memory and the second random memory, including: when performing a write operation on the voltage / current traveling wave signal to the first random memory, performing a read operation on the voltage / current traveling wave signal in the second random memory; or when performing a write operation on the voltage / current traveling wave signal to the second random memory, performing a read operation on the voltage / current traveling wave signal in the first random memory. Such continuous alternating operations ensure that the reading and writing of data do not affect each other, and the traveling wave signal data can be entered and exited in the correct order, and the traveling wave signal data is sent to the subsequent processing module without pause. It can be understood that the data processing unit of the present application also includes an SDRAM controller, for example, an SDRAM1 controller and an SDRAM2 controller. The function of the SDRAM controller is to configure, precharge, refresh, read and write the SDRAM, which is not limited here.

[0155] In the present application, the data processing unit also includes a signal processing module. Specifically, the signal processing module includes: a phase mode transformation module, which is used to perform phase mode transformation on the voltage / current traveling wave signals read from the output asynchronous buffer based on the Karen Bell transformation matrix in turn to extract the line mode components of each voltage / current traveling wave signal; a wavelet analysis module, which is used to extract fault feature information from the extracted line mode components. The function of the phase mode transformation module is to use phase mode transformation to convert the phasor signal into a modulus signal to remove the electromagnetic coupling effect between the three phases. Specifically, Figure 3As shown, the present application uses the Karrenbauer transformation matrix to implement the phase transformation, where X A , X B , X C is the phase component of the voltage or current before transformation, X α , X β , X γ is the transformed line mode component.

[0156] Among them, the wavelet analysis module uses the wavelet transform to have the ability to characterize the local characteristics of the signal in both the time domain and the frequency domain, and can detect the characteristic of singular signals and mutation signals, and analyze the transient voltage and current. For example, when a line fails, the wavelet coefficient will have a modulus maximum value, and the present application can detect the time and position of the mutation point by detecting the modulus maximum value, thereby realizing fault location. The present application uses the general FIR filter IP core provided by FPGA, and by importing the wavelet coefficient into the FIR filter, i.e., the finite length unit impulse response filter, and setting the number of bits and the sign of the input signal, the required wavelet filter can be formed. After the traveling wave signal is subjected to wavelet high-pass filtering through the wavelet filter, the wavelet analysis module further performs modulus maximum value search calculation and polarity judgment on the data to extract fault feature information. The fault analysis module performs fault detection based on the extracted fault feature information by presetting the fault analysis algorithm, thereby obtaining the fault detection result, and generating the corresponding fault detection result signal fault_code. For example, the fault detection result signal can represent different fault categories through different values.

[0157] In the present application, the data processing unit also includes a clock module, which multiplies the external 50M crystal oscillator into the clock required by each module through a phase-locked loop. For example, the clock of the high-speed acquisition module is 50M, the clock of the data cache module is 100M, the clock of the signal processing module is 50M, and the clock of the fault analysis module is 50M.

[0158] In the present application, the wavelet analysis module extracts fault feature information from the extracted line mode component, including: decomposing the extracted line mode component based on wavelet transform to obtain corresponding wavelet transform coefficients, calling a preset modulus maximum search algorithm to perform modulus maximum search on all obtained wavelet transform coefficients, if the modulus maximum search algorithm determines that there is a target modulus maximum that characterizes the line fault, generating a first detection signal that characterizes the detection of the target modulus maximum, and sending the generated first detection signal to the ranging calculation unit. It can be understood that wavelet transform is a prior art, and its transformation process will not be repeated here.

[0159] Among them, Figure 4As shown in the figure, the calculation of the modulus maximum is divided into two stages, namely initial traveling wave detection and reflected wave detection. Each stage defines the initial traveling wave threshold and the initial traveling wave modulus maximum. Then the modulus maximum search algorithm is called, and after the modulus maximum is detected, the modulus maximum, polarity and channel information are stored, where the channel information is used to indicate that the current detection signal is information such as phase A current or phase B voltage.

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

[0161] S1. Determine the wavelet coefficient threshold and initial modulus maximum value; wherein, the wavelet coefficient threshold THRES and initial modulus maximum value mod_max can be determined according to the actual situation, and the amount of calculation and the influence of noise can be effectively reduced by threshold comparison. Take the wavelet coefficient Xn(i) as input, read the threshold value and initialize the modulus maximum value, wherein X represents the voltage or current signal, n represents the channel information, such as ia, ib, ic or ua, ub, uc, and i represents the current i-th wavelet coefficient.

[0162] S2, obtaining a wavelet transform coefficient, comparing the current wavelet transform coefficient with the wavelet coefficient threshold, if the absolute value of the current wavelet transform coefficient is greater than the wavelet coefficient threshold, executing step S3, otherwise, executing step S2;

[0163] S3, compare the current wavelet transform coefficient with the initial modulus maximum value, if the current wavelet transform coefficient is greater than the initial modulus maximum value, update the current initial modulus maximum value with the absolute value of the current wavelet coefficient, that is, set mod_max = |Xn(i)|, and execute step S4, otherwise, execute step S5;

[0164] S4, setting the modulus maximum flag to the first flag, for example, setting the first flag to flag=1, and determining whether the current search number n is greater than a preset search number threshold N, if so, executing step S6, otherwise, executing step S2;

[0165] S5, determine whether the current modulus maximum flag has been set to the first flag, if so, set the current search number n = n + 1, determine whether the current search number is greater than the search number threshold, if so, execute step S6, otherwise, execute step S2, otherwise, execute step S2;

[0166] S6. Taking the current initial modulus maximum as the target modulus maximum, storing the searched modulus maximum, and generating a first detection signal wave_flag representing the detection of the target modulus maximum, wherein the first detection signal can be a first level signal of M consecutive cycles, such as a high level signal.

[0167] In step S3, after the current initial modulus maximum is updated with the absolute value of the current wavelet coefficient, the modulus maximum search algorithm also 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 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 polarity ploar = 0. Then, in step S6, after generating a first detection signal representing that the target modulus maximum is detected, the wavelet analysis module is also used to: generate a second detection signal representing that the target modulus maximum is positive or negative, and the wavelet analysis module simultaneously sends the generated second detection signal to the ranging calculation unit.

[0168] Among them, a second detection signal characterizing whether the target modulus maximum value is positive or negative is generated, including: if the polarity of the target modulus maximum value is determined to be positive, a first level signal is output for multiple consecutive cycles, for example, a high level signal is output for M cycles; if the polarity of the target modulus maximum value is determined to be negative, a second level signal is output for multiple consecutive cycles, for example, a low level signal is output for M cycles.

[0169] The present application searches for the modulus maximum in a cyclic manner. After each search round, the polarity is determined according to the positive or negative value of Xn(i). After the entire search process is completed, the value of the modulus maximum register is stored, and the wave_flag signal outputs a high level that lasts for M cycles. The ploar_flag signal determines whether to output a high level that lasts for M cycles based on the value of polar.

[0170] In the present application, the fault analysis module performs fault detection based on the extracted fault feature information to obtain a fault detection result, including: for each voltage / current traveling wave signal from which the fault feature information is extracted, the extracted line mode components are compared, and the fault detection result is determined according to the comparison result of each line mode component. Among them, 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 is represented by β, and the third line mode component is represented by γ.

[0171] Among them, Figure 6 As shown, the fault detection result is determined according to the comparison result of each line mode component, including:

[0172] S10. If the absolute values ​​of any two of the extracted first line mode component, the second line mode component, and the 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 short circuit 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 an A-phase ground short circuit fault, if |Iα|=|Iγ| and Iβ=0, the fault detection result is determined to be a B-phase ground short circuit fault, and if |Iβ|=|Iγ| and Iα=0, the fault detection result is determined to be a C-phase ground short circuit fault.

[0173] S12. 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. For example, if |Iα|>|Iγ| and |Iα|>|Iβ|, the fault detection result is determined to be an AB two-phase ground short circuit fault, if |Iγ|>|Iα| and |Iγ|>|Iβ|, the fault detection result is determined to be a BC two-phase ground short circuit fault, if |Iβ|>|Iγ| and |Iβ|>|Iα|, the fault detection result is determined to be an AC two-phase ground short circuit fault.

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

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

[0176] In the present application, the ranging calculation unit is also used to: when the first detection signal is received for the first time, determine the first time when the first detection signal is first received, and if the first detection signal is received again within the first interval time, determine the second time when the first detection signal is received again, and determine the time difference between the first time and the second time. Specifically, Figure 7As shown, the running program of the ranging calculation unit MCU of the present 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. In order to ensure the real-time performance of data calculation, the main frequency of the ranging calculation unit MCU of the present application is above 200M, and the wave_flag signal is detected by an external interrupt. When the wave_flag is detected for the first time, the time t1 is recorded and the polarity ploar1 is recorded; if the wave_flag signal is detected again after an interval of T1, the time t2 is recorded and the polarity ploar2 is recorded, and then the single-ended ranging calculation is performed, and this round of calculation ends; if the wave_flag is not detected again after T2, the current round of calculation ends.

[0177] Among them, determining the first fault location information according to the received first detection signal includes: obtaining the second detection signal corresponding to the first detection signal received for the first time, and obtaining the second detection signal corresponding to the first detection signal received again, that is, obtaining the polarity information of the modulus maximum values ​​extracted from the initial traveling wave and the transmission wave; calling the corresponding single-ended ranging algorithm to determine the first fault location information based on the comparison result of the second detection signal received for the first time and the second detection signal received again, and comparing the polarities of the modulus maximum values ​​extracted from the initial traveling wave and the transmission wave.

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

[0179]

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

[0181] If the polarities represented by the second detection signal received for the first time and the second detection signal received again are different, the first fault location information is determined by the following algorithm:

[0182]

[0183] Among them, D singlerepresents the distance between the fault point and 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 endpoint closest to the current detection point on the distribution line where the current detection point is located, wherein the distribution line where the current detection point is located has multiple detection points, and there is no other detection point between the current detection point and the endpoint. For example, see Fig. 9 , M is the endpoint of the distribution line where the detection point A is located, that is, L is the distance between AM. It can be understood that there are multiple pole switches on the same distribution line, that is, multiple detection points are usually arranged. When one side of the current detection point is the endpoint of the current distribution line, the location of the fault point can be determined by the single-ended ranging algorithm.

[0184] In the ranging calculation unit, the clock processing module is used to provide a stable and accurate clock, wherein the high-precision clock is implemented by the Beidou timing module. Since the Beidou timing is aligned at the whole second by means of second pulses, in order to achieve a high-stability clock, the device's timekeeping accuracy is also required to be sufficient during the second pulse, and the clock crystal oscillator is a factor that directly affects the timekeeping accuracy. Conventional ranging devices are usually implemented using a highly stable constant temperature crystal oscillator, but the constant temperature crystal oscillator consumes high power and is expensive. The present application uses a high-precision temperature compensated crystal oscillator to replace the existing constant temperature crystal oscillator, and uses the Beidou module for real-time correction, wherein the ranging deviation introduced by the crystal oscillator error can be 20-30 meters, which can meet the ranging requirements.

[0185] Among them, the clock information includes two parts. One part is the absolute time scale accurate to the second level, including year, month, day, hour, minute, and second; the other part is the microsecond clock. The implementation method of the microsecond clock is: the internal timer of the MCU counts, and the clock reference is an external crystal oscillator for frequency multiplication, such as 100M. The MCU reads the time of the Beidou module at regular intervals (for example, one hour) to eliminate the accumulated error of the second clock. The microsecond clock value is corrected using the 1PPS signal of the Beidou module to ensure accuracy. The correction method is that when the 1PPS second pulse triggers the external interrupt of the MCU, the count value of the timer is saved and the timer is cleared. The microsecond value at a certain moment is (current timer count value / last timer count value) × 1000000, and the calculation formula is as follows:

[0186]

[0187] Among them, t us is the microsecond value at a certain moment, T now is the current timer count value, T last The last timer count value.

[0188] The communication processing module of the distance measurement calculation unit is used to exchange data with the master station. This module receives the first travel wave time t1 and the single-ended fault distance data D calculated by the distance measurement calculation module. single And the fault code fault_code from FPGA, and upload these data to the master station for processing.

[0189] In a second aspect of the present application, a power distribution terminal is provided, comprising: a control unit; and the above-mentioned distribution network traveling wave ranging device; wherein the control unit is in communication connection with the ranging calculation unit of the distribution network traveling wave ranging device, and is used to receive the first time, the first fault location information and the fault detection result sent by the ranging calculation unit. It can be understood that the power distribution terminal can be based on an existing FTU, and the control unit is the controller of the existing FTU. The present application integrates the distribution network traveling wave ranging device into the existing FTU, which can effectively reduce the equipment cost.

[0190] In a third aspect of the present application, a distribution network fault monitoring system is provided, comprising: a master station; and a plurality of distribution terminals as described above; wherein the master station is respectively communicatively connected with each distribution terminal, for receiving a first time, a first fault location information and a fault detection result sent by each distribution terminal, and determining 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 the present application, a distribution network fault monitoring method is provided, which is applied to a master station in the above distribution network fault monitoring system, and the method includes:

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

[0193] S210, if any side of the current distribution terminal is an endpoint of the current distribution line, determine whether the first time or first fault location information sent by the first adjacent distribution terminal of the current distribution terminal on the current distribution line is received within a preset time range;

[0194] S211, if the first time or first fault location information sent by the first adjacent distribution terminal is received within the preset time range, it is determined that the fault point is located between the current distribution terminal and the adjacent distribution terminal, and the two-terminal 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 the current distribution line corresponding to it, and the first fault location information is used as the second fault location information;

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

[0197] In step S100, the master station monitors all the ranging devices on the distribution line. When the master station receives fault data sent by any ranging device within a certain time range T0, that is, the first time when the master station receives the first detection signal of the ranging device detecting the target modulus maximum value of the traveling wave signal 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 endpoint of the distribution line. It can be understood that in the present application, the ranging device is integrated in the distribution terminal, and the determination of the ranging device is the same as the determination of the corresponding distribution terminal.

[0198] Among them, judging whether any side of the current distribution terminal is the endpoint of the current distribution line includes: if there are no other distribution terminals between the current distribution terminal and the endpoint of any side of the current distribution line where it is located, determining that the corresponding side of the current distribution terminal is the endpoint of the current distribution line, otherwise, determining that the corresponding side of the current distribution terminal is not the endpoint of the current distribution line. For example, on the distribution line A where the distribution terminal A is located, the first side endpoint of the distribution line A is endpoint 1, and the second side endpoint of the distribution line A is endpoint 2, then, if there are no other distribution terminals between the distribution terminal A and the endpoint 1 of the distribution line A, then determining that the first side of the distribution terminal A is the endpoint of the distribution line A, or, if there are no other distribution terminals between the distribution terminal A and the endpoint 2 of the distribution line A, then determining that the second side of the distribution terminal A is the endpoint of the distribution line A.

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

[0200] like Fig. 9 As shown, the fault location strategy of this application is described by taking the typical T-shaped connection of the branch line of the distribution network as an example. Fig. 9, M, N, and P are the three endpoints of the distribution line, A, B, and C represent section switches or branch switches, wherein A, B, and C are all equipped with FTUs. For the existing traditional two-end distance measurement method, the distance measurement device needs to be installed at the endpoints M, N, and P, while the present application installs the distance measurement device at A, B, and C, i.e., the switch position, and integrates or connects with the FTU, thereby reducing repeated equipment investment and construction difficulty. Accurate fault location can be achieved in conjunction with the fault location strategy of the master station, wherein the overall topological structure of the distribution line and the distance from each endpoint to each switch are predetermined. Since refraction and reflection occur when the traveling wave propagates to the connection point of the line, and the traveling wave modulus maximum value is filtered by the threshold THRES when it is judged, it can be considered that the fault traveling wave cannot propagate across the switch. Therefore, when a line fault occurs, the master station will receive fault data sent by the FTU on the line adjacent to the fault point, wherein F1, F2, and F3 are the fault points of line faults at three different locations.

[0201] In step S211, if after receiving the fault data sent by the current distance measuring device, the fault data sent by the distance measuring device adjacent to the current distance measuring device is received within the time range of T0, it is determined that the fault point is located between the current distance measuring device and the adjacent distance measuring device. For example, if after receiving the fault data sent by the distance measuring device at point A, the fault data sent by the distance measuring device at point B and the distance measuring device at point C are received within T0, it can be determined that the fault point is between point A and point B, or between point A and point C. At this time, the double-end ranging algorithm is called to calculate the fault point location information.

[0202] The two-terminal distance measurement algorithm includes: obtaining the distance between the current distribution terminal and the first adjacent distribution terminal, for example, Fig. 9 If the distribution terminal at point A is the current distribution terminal, the distance between point A and point B is obtained, as well as the transmission speed of the voltage / current traveling wave signal; according to 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, the first distance between the current distribution terminal and the fault point is calculated through a preset first distance measurement model, and the second distance between the first adjacent distribution terminal and the fault point is 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, so as to obtain the fault location information of the fault point. Fig. 9 For example, if there is no branch line OP between the distribution lines MN, the location of the fault point can be determined according to the calculated first distance or second distance.

[0203] The first ranging model includes:

[0204]

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

[0206] In the present application, if there are other branch distribution lines between the current distribution terminal and the first adjacent distribution terminal, the two-terminal distance measurement algorithm further includes: obtaining a third distance between the current distribution terminal and the branch connection point of the corresponding branch distribution line on the current distribution line, for example, Fig. 9 The distribution terminal at point A is the current distribution terminal, then the distance from point A to point O is obtained, and the second adjacent distribution terminal closest to the branch connection point on the corresponding branch distribution line is obtained, such as the first time sent by the distribution terminal at point C, 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 is different from the third distance, for example, Fig. 9 In, L AF ≠L AO , it can be determined that the fault point is between AB, and the second fault location information of the fault point is determined based on the first distance or the second distance, and L is solved. AF or L BF The fault point F1 can be located; if the first distance is the same as the third distance, that is, L AF =L AO , it can be determined that the fault point is on the branch line whose connection point is O in AB. According to the third distance, the fourth distance, the transmission speed of the voltage / current traveling wave signal, the first time from the current distribution terminal and the first time from the second adjacent distribution terminal, the fifth distance between the current distribution terminal and the fault point, and the sixth distance between the second adjacent distribution terminal and the fault point are calculated through the preset second ranging model; the second fault location information of the 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 is the fifth distance between the current distribution terminal and the fault point, D CF is the sixth distance between the second adjacent distribution terminal and the fault point, v is the transmission speed of the voltage / current traveling wave signal, T FA is the first time from the current distribution terminal, TFC For the first time from the second adjacent distribution terminal, L AO is the third distance between the current distribution terminal and the branch point, L CO is the fourth 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 end point of a power distribution line, for example, Fig. 9 In the process, if after receiving the fault data sent by the distribution terminal at point A, no fault data sent by other distribution terminals is received within T0, then it can be determined that the fault point is between the current distribution terminal and its corresponding endpoint of the current distribution line, that is, the fault point F2 is located between point A and endpoint M. The single-ended ranging algorithm is directly sampled to locate the fault point. Since the first fault location information received is calculated by the ranging device through the single-ended ranging algorithm, the result can be directly sampled.

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

[0212] It can be understood that in this application, voltage and current traveling wave signals can be collected at the same time. Since current and voltage traveling waves have the same movement speed on the same line, the fault distance can be accurately measured by using the current and voltage traveling waves at both ends of the line. Among them, when performing fault distance measurement in this application, the signal selection method includes: for the bus end of the fault line, there are usually more outgoing lines in the distribution system. At this time, the initial current traveling wave amplitude at the bus measurement end is large, and the initial voltage traveling wave amplitude is small, so the current traveling wave is used as the distance measurement signal; for the end of the line that supplies power to users and enterprises, due to the load transformer, for the high-frequency traveling wave signal, its AC impedance is very large, which is approximately an open circuit state. At this time, the initial current traveling wave at the end of the line is almost zero, and the initial voltage traveling wave is close to twice the incident wave, so the voltage traveling wave is used as the distance measurement signal; for the middle section of the line, the current and voltage traveling wave signals are comprehensively utilized, and the one with the best signal quality is selected as the distance measurement signal.

[0213] like Fig.10 As shown, in a fifth aspect of the present application, a distribution network fault monitoring device is provided, and the distribution network fault monitoring method is applied, and the device includes:

[0214] An information receiving module is configured to determine whether any side of the current distribution terminal is an endpoint of the current distribution line in response to the first time or first fault location information sent by any distribution terminal;

[0215] A judgment module is configured to judge whether the first time or first fault location information sent by the first adjacent distribution terminal of the current distribution terminal on the current distribution line is received within a preset time range if any side of the current distribution terminal is an endpoint of the current distribution line;

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

[0217] 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 the current distribution line corresponding to it, and the first fault location information is used as the second fault location information; and

[0218] If either side of the current distribution terminal is not an endpoint of the current distribution line, and the first fault location information sent by the first adjacent distribution terminal is received within a preset time range, the two-terminal ranging algorithm is called 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 the endpoint on either side of the current distribution line where it is located, the corresponding side of the current distribution terminal is determined to be the endpoint of the current distribution line; otherwise, it is determined that the corresponding side of the current distribution terminal is not the endpoint of the current distribution line.

[0221] Optionally, a two-terminal ranging algorithm includes:

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

[0223] According to 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 by a preset first distance measurement 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 distribution lines between the current distribution terminal and the first adjacent distribution terminal, second fault location information of the fault point is determined based on the first distance or the second distance.

[0225] Optionally, the dual-end ranging algorithm further 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;

[0227] If the first distance is different from the third distance, determining second fault location information of the fault point based on the first distance or the second distance;

[0228] If the first distance is the same as the third distance, the fifth distance between the current distribution terminal and the fault point, and the sixth distance between the second adjacent distribution terminal and the fault point are calculated by a preset second distance measurement model according to the third distance, the fourth distance, the transmission speed of the voltage / current traveling wave signal, the first time from the current distribution terminal, and the first time from the second adjacent distribution terminal;

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

[0230] Optionally, the first ranging model includes:

[0231]

[0232] Among them, D AF is the first distance between the current distribution terminal and the fault point, D BF is the second distance between the first adjacent distribution terminal and the fault point, v is the transmission speed of the voltage / current traveling wave signal, T FA is the first time from the current distribution terminal, T FB For the first time from the first adjacent distribution terminal, L AB 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 is the fifth distance between the current distribution terminal and the fault point, D CF is the sixth distance between the second adjacent distribution terminal and the fault point, v is the transmission speed of the voltage / current traveling wave signal, T FA is the first time from the current distribution terminal, T FC For the first time from the second adjacent distribution terminal, L AO is the third distance between the current distribution terminal and the branch point, L CO is the fourth distance between the second adjacent distribution terminal and the branch connection point.

[0236] It is understandable that the technical personnel in the relevant field can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example. In practical applications, the above-mentioned function allocation can be completed by different functional units and modules as needed, that is, the internal structure of the device is divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiment can be integrated in a processing unit, or each unit can exist physically separately, or two or more units can be integrated in one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of this application. The specific working process of the units and modules in the above-mentioned system can refer to the corresponding process in the aforementioned method embodiment, which will not be repeated here.

[0237] In a sixth aspect of the present application, a machine-readable storage medium is provided, on which instructions are stored, and when the instructions are executed by a processor, the processor is configured to execute the distribution network fault monitoring method as described above.

[0238] In a seventh aspect of the present application, a terminal device is provided, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the distribution network fault monitoring method as described above when executing the computer program.

[0239] like Fig.11 FIG. 1 is a schematic diagram of a terminal device provided in an embodiment of the present application. Fig.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, the steps in the above method embodiment are implemented. Alternatively, when the processor 100 executes the computer program 102, the functions of each module / unit in the above device embodiments are implemented.

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

[0241] The terminal device 10 may be a computing device such as a desktop computer, a notebook, a PDA, or a cloud server. The terminal device 10 may include, but is not limited to, a processor 100 and a memory 101. Those skilled in the art will appreciate that Fig.11 It is only an example of the terminal device 10 and does not constitute a limitation of the terminal device 10. It may include more or fewer components than shown in the figure, or a combination of certain components, or different components. For example, the terminal device may also include input and output devices, network access devices, buses, etc.

[0242] The processor 100 may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or the processor may be any conventional processor, etc.

[0243] The memory 101 may be an internal storage unit of the terminal device 10, such as a hard disk or memory of the terminal device 10. The memory 101 may also be an external storage device of the terminal device 10, such as a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, etc. equipped on the terminal device 10. Further, the memory 101 may also include both an internal storage unit of the terminal device 10 and an external storage device. The memory 101 is used to store computer programs and other programs and data required by the terminal device 10. The memory 101 may also be used to temporarily store data that has been output or is to be output.

[0244] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include computer-usable program code.

[0245] In summary, if the traditional two-terminal traveling wave ranging device is used in the distribution network, it will require a large investment due to the large number of branches in the distribution network, and the construction and transformation are difficult. The device of the present application can be directly installed in the distribution terminal (FTU), relying on the FTU and the main station for communication, and performing single-ended ranging and double-ended ranging calculations in the device at the same time. The results calculated by the two methods are uploaded to the main station at the same time. The main station locates the fault point through corresponding strategy judgment. Compared with the traditional two-terminal ranging method, the number of ranging devices deployed can be reduced, which can greatly reduce the investment and construction costs while reducing the difficulty of construction and transformation. At the same time, since the location of the FTU deployment is not necessarily the end point of the line, the present application can also effectively solve the problem of measurement blind spots; in addition, the present application The fault ranging device is developed based on FPGA to achieve high-speed sampling and processing of traveling wave data. The data before and after the fault are analyzed by wavelet transform to obtain the mutation point of the signal, thereby accurately capturing the traveling wave head, effectively solving the problems of small power supply radius and weak fault signal of the distribution network, low positioning accuracy, leakage detection and error detection. At the same time, the application analyzes the fault type based on the amplitude and polarity characteristics of the fault waveform. Rapid fault analysis can be achieved based on the fault ranging device without additional cost. At the same time, the fault code can be uploaded to the master station to provide a reference basis for the diagnosis of distribution network faults.

[0246] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0247] The above are only embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included within the scope of the claims of the present application.

Claims

1. A traveling wave ranging device for a distribution network, characterized in that: include: A mutual inductor arranged on the switch pole on the corresponding column is used to collect the voltage / current traveling wave signal of the corresponding detection point; Data processing unit, including: A phase mode conversion module, used for performing phase mode conversion on the voltage / current traveling wave signal to extract the line mode component of each voltage / current traveling wave signal; A wavelet analysis module is used to decompose the extracted line mode components based on wavelet transform to obtain corresponding wavelet transform coefficients, call a preset modulus maximum search algorithm to perform modulus maximum search on all obtained wavelet transform coefficients, and if the modulus maximum search algorithm determines that there is a target modulus maximum representing a line fault, a first detection signal is generated, and the first detection signal represents that the target modulus maximum is detected; The distance measurement calculation unit is used to receive the first detection signal generated by the wavelet analysis module, and determine the first fault location information according to the received first detection signal.

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

3. The distribution network traveling wave ranging device according to claim 2, characterized in that: The distribution network traveling wave ranging device also includes: A signal conditioning unit, used for preprocessing the voltage / current traveling wave signal collected by the transformer, and sending the preprocessed voltage / current traveling wave signal to the signal conversion unit; The preprocessing at least includes amplifying and filtering the voltage / current traveling wave signal collected by the transformer.

4. The 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 a control signal and a clock signal to the signal conversion unit to perform data acquisition on 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 distribution network traveling wave ranging device according to claim 4, characterized in that: The data cache module comprises: An input asynchronous buffer, an output asynchronous buffer, a first random access memory, a second random access memory and a cache controller; The input asynchronous buffer is used to buffer the voltage / current traveling wave signal from the high-speed acquisition module; The cache controller is used to read the voltage / current traveling wave signals from the input asynchronous cache in sequence, and alternately store the read voltage / current traveling wave signals in the first random access memory and the second random access memory, and alternately read the voltage / current traveling wave signals from the first random access memory and the second random access memory, and store the read voltage / current traveling wave signals in sequence in the output asynchronous cache.

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

7. The traveling wave ranging device for distribution network according to claim 6, characterized in that: Alternately reading voltage / current traveling wave signals from the first random access memory and the second random access memory, comprising: When a voltage / current traveling wave signal is written into the first random access memory, a voltage / current traveling wave signal is read from the second random access memory; or When a write operation of a voltage / current traveling wave signal is performed on the second random access memory, a read operation of a voltage / current traveling wave signal is performed on the first random access memory.

8. The traveling wave ranging device for distribution network 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 in sequence based on the Karenberg transformation matrix to extract the line mode components of each voltage / current traveling wave signal.

9. The traveling wave ranging device for distribution network according to claim 8, characterized in that: The data processing unit further includes: The fault analysis module is used to compare the extracted line mode components for each voltage / current traveling wave signal from which fault characteristic information is extracted, and determine the fault detection result according to the comparison result of each line mode component.

10. The traveling wave ranging device for distribution network according to claim 1, characterized in that: The modulus maximum value search algorithm comprises: S1, determine the wavelet coefficient threshold and the initial modulus maximum; S2, obtaining a wavelet transform coefficient, comparing the current wavelet transform coefficient with the wavelet coefficient threshold, if the absolute value of the current wavelet transform coefficient is greater than the wavelet coefficient threshold, executing step S3, otherwise, executing step S2; S3, compare the current wavelet transform coefficient with the initial modulus maximum value, if the current wavelet transform coefficient is greater than the initial modulus maximum value, update the current initial modulus maximum value with the absolute value of the current wavelet coefficient, and execute step S4, otherwise, execute step S5; S4, setting the modulus maximum flag bit to the first flag, and determining whether the current search times are greater than a preset search times threshold, if so, executing step S6, otherwise, executing step S2; S5, determining whether the current modulus maximum flag has been set to the first flag, if so, determining whether the current search times are greater than the search times threshold, if so, executing step S6, otherwise, executing step S2, otherwise, executing step S2; S6. Taking the current initial modulus maximum value as the target modulus maximum value, a first detection signal is generated to indicate that the target modulus maximum value is detected.

11. The traveling wave ranging device for distribution network according to claim 10, characterized in that: After updating the current initial modulus maximum value with the absolute value of the current wavelet coefficient, the modulus maximum value search algorithm further includes: Determine 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, the polarity of the current wavelet coefficient is determined to be positive. If the value of the current wavelet transform coefficient is less than or equal to zero, the polarity of the current wavelet coefficient is determined to be negative.

12. The distribution network traveling wave ranging device according to claim 11, characterized in that: After generating the first detection signal indicating that the target modulus maximum value is detected, the wavelet analysis module is further used to: A second detection signal is generated to indicate that the target modulus maximum value is positive or negative, and the generated second detection signal is sent to the distance measurement calculation unit.

13. The traveling wave ranging device for distribution network according to claim 12, characterized in that: Generating a second detection signal indicating that the target modulus maximum value is positive or negative, comprising: If it is determined that the polarity of the target modulus maximum value is positive, outputting a first level signal for a plurality of consecutive cycles; If it is determined that the polarity of the target modulus maximum value is negative, a second level signal is output for a plurality of consecutive cycles.

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

15. The traveling wave ranging device for distribution network according to claim 9, characterized in that: Line mode components of each voltage / current traveling wave signal, including: 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; The fault detection result is determined based on the comparison results of each line mode component, including: If the absolute values ​​of any two of the extracted first line mode component, the second line mode component and the third line mode component are equal, and the value of the other one is zero, it is determined that the fault detection result is a single-phase ground short circuit fault; If the absolute value of any one of the extracted first line mode component, the second line mode component and the third line mode component is greater than the absolute values ​​of the other two, it is determined that the fault detection result is a two-phase ground short circuit fault; If the absolute value of any one of the extracted first line mode component, the second line mode component and the third line mode component is equal to twice the absolute value of the other two, it is determined that the fault detection result is a two-phase short circuit fault; If the absolute values ​​of the extracted first line mode component, the second line mode component and the third line mode component are all greater than zero, and the absolute values ​​of the extracted first line mode component, the second line mode component and the third line mode component are all different, the fault detection result is determined to be a three-phase ground short circuit fault.

16. The traveling wave ranging device for distribution network according to claim 12, characterized in that: The distance measurement calculation unit is further used for: When the first detection signal is received for the first time, determining a first time when the first detection signal is first received, and if the first detection signal is received again within the first interval, determining a second time when the first detection signal is received again, and determining a time difference between the first time and the second time; Determining first fault location information according to the received first detection signal includes: Acquire a second detection signal corresponding to the first detection signal received for the first time, and acquire a second detection signal corresponding to the first detection signal received again; The first fault location information is determined by calling a corresponding single-ended ranging algorithm according to a comparison result of the first received second detection signal and the second received second detection signal.

17. The traveling wave ranging device for distribution network according to claim 16, characterized in that: Calling a corresponding single-ended ranging algorithm to determine first fault location information according to a comparison result of the first received second detection signal and the second received second detection signal includes: If the polarity represented by the second detection signal received for the first time is the same as the polarity represented by the second detection signal received again, the first fault location information is determined by the following algorithm: Among them, D single It represents the distance between the fault point and 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.

18. The traveling wave ranging device for distribution network according to claim 16, characterized in that: Calling a corresponding single-ended ranging algorithm to determine first fault location information according to a comparison result of the first received second detection signal and the second received second detection signal includes: If the polarity represented by the second detection signal received for the first time is different from the polarity represented by the second detection signal received again, the first fault location information is determined by the following algorithm: Among them, D single represents the distance between the fault point and 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 endpoint closest to the current detection point on the distribution line where the current detection point is located, wherein there are multiple detection points set on the distribution line where the current detection point is located, and there are no other detection points between the current detection point and the endpoint.

19. A power distribution terminal, characterized in that: include: Control unit; as well as The distribution network traveling wave ranging device as described in any one of claims 16 to 18; The control unit is communicatively connected with the distance measurement calculation unit of the distribution network traveling wave distance measurement device, and is used to receive the first time, the first fault location information and the fault detection result sent by the distance measurement calculation unit.

20. A distribution network fault monitoring system, characterized in that: include: Main station; as well as A plurality of power distribution terminals as claimed in claim 19; The master station is respectively connected to each distribution terminal for receiving the first time, first fault location information and fault detection result sent by each distribution terminal, and determining the second fault location information of the fault point based on the received first time or first fault location information.

21. A distribution network fault monitoring method, applied to a master station in the distribution network fault monitoring system according to claim 20, characterized in that: The method comprises: In response to the first time or first fault location information sent by any power distribution terminal, determining whether any side of the current power distribution terminal is an endpoint of the current power distribution line; If any side of the current power distribution terminal is an endpoint of the current power distribution line, determine whether the first time or first fault location information sent by the first adjacent power distribution terminal of the current power distribution terminal on the current power distribution line is received within a preset time range; If the first time or first fault location information sent by the first adjacent distribution terminal is received within the preset time range, it is determined that the fault point is located between the current distribution terminal and the adjacent distribution terminal, and the two-terminal 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 the current distribution line corresponding to it, and the first fault location information is used as the second fault location information; If neither side of the current distribution terminal is an endpoint of the current distribution line, and the first fault location information sent by the first adjacent distribution terminal is received within the preset time range, the two-terminal ranging algorithm is called to calculate the second fault location information of the fault point.

22. A distribution network fault monitoring method according to claim 21, characterized in that: Determine whether any side of the current power distribution terminal is the endpoint of the current power distribution line, including: If there are no other distribution terminals between the current distribution terminal and the endpoint on either side of the current distribution line where it is located, the corresponding side of the current distribution terminal is determined to be the endpoint of the current distribution line; otherwise, it is determined that the corresponding side of the current distribution terminal is not the endpoint of the current distribution line.

23. A distribution network fault monitoring method according to claim 21, characterized in that: The dual-end ranging algorithm comprises: Obtaining the distance between the current power distribution terminal and the first adjacent power distribution terminal, and obtaining the transmission speed of the voltage / current traveling wave signal; According to 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 by a preset first distance measurement model, and the second distance between the first adjacent power distribution terminal and the fault point is calculated; If there are no other branch distribution lines between the current distribution terminal and the first adjacent distribution terminal, second fault location information of the fault point is determined based on the first distance or the second distance.

24. A distribution network fault monitoring method according to claim 23, 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 a third distance between the current distribution terminal and a branch connection point of the corresponding branch distribution line on the current distribution line, and obtain a first time sent by a second adjacent distribution terminal closest to the branch connection point on the corresponding branch distribution line, and a fourth distance between the second adjacent distribution terminal and the branch connection; If the first distance is different from the third distance, determining second fault location information of the fault point based on the first distance or the second distance; If the first distance is the same as the third distance, the fifth distance between the current distribution terminal and the fault point, and the sixth distance between the second adjacent distribution terminal and the fault point are calculated by a preset second distance measurement model according to the third distance, the fourth distance, the transmission speed of the voltage / current traveling wave signal, the first time from the current distribution terminal, and the first time from the second adjacent distribution terminal; Second fault location information of the fault point is determined based on the fifth distance or the sixth distance.

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

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

27. A distribution network fault monitoring device, using the distribution network fault monitoring method according to any one of claims 21 to 26, characterized in that: The device comprises: An information receiving module is configured to respond to the first time or first fault location information sent by any power distribution terminal to determine whether any side of the current power distribution terminal is an endpoint of the current power distribution line; A judgment module is configured to judge whether the first time or first fault location information sent by the first adjacent distribution terminal of the current distribution terminal on the current distribution line is received within a preset time range if any side of the current distribution terminal is an endpoint of the current distribution line; The distance measurement calculation module is configured to, if the first time or first fault location information sent by the first adjacent distribution terminal is received within the preset time range, determine that the fault point is located between the current distribution terminal and the adjacent distribution terminal, and call the two-terminal distance measurement algorithm 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 the current distribution line corresponding to it, and the first fault location information is used as the second fault location information; and If neither side of the current distribution terminal is an endpoint of the current distribution line, and the first fault location information sent by the first adjacent distribution terminal is received within the preset time range, the two-terminal ranging algorithm is called to calculate the second fault location information of the fault point.

28. A distribution network fault monitoring device according to claim 27, characterized in that: Determine whether any side of the current power distribution terminal is the endpoint of the current power distribution line, including: If there are no other distribution terminals between the current distribution terminal and the endpoint on either side of the current distribution line where it is located, the corresponding side of the current distribution terminal is determined to be the endpoint of the current distribution line; otherwise, it is determined that the corresponding side of the current distribution terminal is not the endpoint of the current distribution line.

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

30. A distribution network fault monitoring device according to claim 29, 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 a third distance between the current distribution terminal and a branch connection point of the corresponding branch distribution line on the current distribution line, and obtain a first time sent by a second adjacent distribution terminal closest to the branch connection point on the corresponding branch distribution line, and a fourth distance between the second adjacent distribution terminal and the branch connection; If the first distance is different from the third distance, determining second fault location information of the fault point based on the first distance or the second distance; If the first distance is the same as the third distance, the fifth distance between the current distribution terminal and the fault point, and the sixth distance between the second adjacent distribution terminal and the fault point are calculated by a preset second distance measurement model according to the third distance, the fourth distance, the transmission speed of the voltage / current traveling wave signal, the first time from the current distribution terminal, and the first time from the second adjacent distribution terminal; Second fault location information of the fault point is determined based on the fifth distance or the sixth distance.

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

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

33. A machine-readable storage medium having instructions stored thereon, characterized in that: When the instruction is executed by a processor, the processor is configured to execute the distribution network fault monitoring method as described in any one of claims 21 to 26.

34. 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, the steps of the distribution network fault monitoring method as described in any one of claims 21 to 26 are implemented.

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