Fault positioning method of low-voltage power distribution network, intelligent circuit breaker and system

Abstract

The invention discloses a fault positioning method of a low-voltage power distribution network, an intelligent circuit breaker and a system. The fault positioning method comprises the following steps: acquiring an electrical signal on an external line through an electrical quantity transformer of the intelligent circuit breaker; power frequency signals in the electrical signals are filtered out, and high-frequency signals are reserved; amplifying the amplitude of the high-frequency signal to obtain a high-frequency amplitude signal; and judging whether a line fault exists or not based on the high-frequency amplitude signal, and if the line fault exists, carrying out fault positioning based on the high-frequency amplitude signal. According to the invention, tiny electrical signals can be accurately identified, and accurate fault positioning can be realized through the intelligent circuit breaker.

Description

Technical Field

[0001] The present application relates to the field of fault location, and in particular to a fault location method, an intelligent circuit breaker and a system for a low-voltage distribution network. Background Art

[0002] In recent years, with the increasing number of intelligent power distribution equipment, low-voltage intelligent molded case circuit breakers, as key components of low-voltage power distribution networks, bear the important task of fault location.

[0003] At present, low-voltage distribution networks mainly rely on power frequency signals for fault location, but this method can only roughly determine the fault location to the area of ​​the substation, and the accuracy is limited. In addition, low-voltage intelligent molded case circuit breakers will generate large currents during normal operation, which makes it challenging to identify small current changes, thus affecting the accuracy of fault location. Although some practices are to add branch circuit breakers to the branch boxes in the low-voltage substation to achieve more detailed fault location, even so, the fault location can only be narrowed to the line level, and the high-precision requirements for low-voltage line fault location cannot be met. What's more unfavorable is that this approach also adds additional cost investment for branch circuit breakers.

[0004] Application Contents

[0005] The present application provides a fault location method, an intelligent circuit breaker and a system for a low-voltage distribution network to accurately identify tiny electrical signals, thereby achieving accurate fault location through the intelligent circuit breaker.

[0006] In a first aspect, the present application provides a fault location method for a low-voltage distribution network, which is applicable to an intelligent circuit breaker. The fault location method includes:

[0007] Collecting electrical signals on external lines through the electrical quantity transformer of the intelligent circuit breaker;

[0008] filtering out the power frequency signal in the electrical signal and retaining the high frequency signal;

[0009] amplifying the amplitude of the high-frequency signal to obtain a high-frequency amplitude signal;

[0010] Based on the high-frequency amplitude signal, it is determined whether there is a line fault. If there is a line fault, the fault is located based on the high-frequency amplitude signal.

[0011] The embodiment of the present application collects electrical signals on the external line through the electrical quantity transformer of the intelligent circuit breaker, and can accurately identify the tiny electrical signals on the external line, which is convenient for subsequent accurate fault location through the intelligent circuit breaker; by filtering the power frequency signal in the electrical signal, the high-frequency signal containing abnormal discharge characteristics can be accurately retained, which is convenient for subsequent accurate fault location through the intelligent circuit breaker; by amplifying the amplitude of the high-frequency signal, the amplitude in the high-frequency signal can be amplified, which is convenient for subsequent processing and analysis, and helps to accurately locate the fault through the intelligent circuit breaker in the future; based on the high-frequency amplitude signal, it is judged whether there is a line fault, and the line fault judgment can be accurately performed based on the high-frequency amplitude signal. When there is a line fault, the intelligent circuit breaker can accurately locate the fault. Compared with the prior art, the present application can accurately identify tiny electrical signals, thereby realizing accurate fault location through the intelligent circuit breaker.

[0012] Furthermore, before filtering out the power frequency signal in the electrical signal, the method further includes:

[0013] Acquire a time signal corresponding to the electrical signal;

[0014] If the electrical signal is greater than a preset electrical threshold and the time signal exceeds a preset time threshold, a protection action is performed on the low-voltage distribution network based on the intelligent circuit breaker.

[0015] In this way, by performing protective actions on the low-voltage distribution network, the safe and stable operation of the power system can be ensured.

[0016] Furthermore, if there is a line fault, the fault location is performed based on the high-frequency amplitude signal, specifically:

[0017] Converting the high frequency amplitude signal of the line fault into corresponding traveling wave data;

[0018] Obtain the timestamp of the traveling wave data from the fault point to the intelligent circuit breaker, determine the distance from the fault point to the intelligent circuit breakers at both ends based on the timestamp, and determine the fault point location of the low-voltage distribution network based on the distance.

[0019] In this way, by judging whether there is a line fault, the line fault can be accurately judged based on the high-frequency amplitude signal. When a line fault exists, the intelligent circuit breaker can be used to accurately locate the fault.

[0020] Furthermore, the obtaining of the timestamp of the traveling wave data from the fault point to the intelligent circuit breaker and the determination of the distance from the fault point to the intelligent circuit breakers at both ends based on the timestamp are specifically as follows:

[0021] Determine the first time when the traveling wave head reaches the intelligent circuit breaker from the fault point based on the traveling wave data;

[0022] Receiving a second time when the traveling wave header sent by the intelligent circuit breaker arranged at the other end of the line arrives at the intelligent circuit breaker arranged at the other end of the line from the fault point;

[0023] The distances from the fault point to the intelligent circuit breaker and the distance from the intelligent circuit breaker at the other end are calculated based on the first time and the second time.

[0024] In this way, by judging whether there is a line fault, the line fault can be accurately judged based on the high-frequency amplitude signal. When a line fault exists, the intelligent circuit breaker can be used to accurately locate the fault.

[0025] Furthermore, the calculation formula for respectively calculating the distance from the fault point to the intelligent circuit breaker and the distance from the intelligent circuit breaker at the other end based on the first time and the second time is specifically:

[0026]

[0027] Where, L M and L N The fault point to the intelligent circuit breaker M and the distance between the intelligent circuit breaker N at the other end; L is the distance between the intelligent circuit breaker and the intelligent circuit breaker N at the other end; v is the propagation speed of the traveling wave data; t M For the fault point to the intelligent circuit breaker M The first time; N It is the second time from the fault point to the intelligent circuit breaker N at the other end.

[0028] In a second aspect, the present application provides an intelligent circuit breaker, comprising: an electrical quantity transformer, a high-pass filter module, an amplification module, and a fault processor;

[0029] The electrical quantity transformer is used to collect electrical signals on external lines;

[0030] The high-pass filter module is used to filter out the power frequency signal in the electrical signal and retain the high-frequency signal;

[0031] The amplification module is used to amplify the amplitude of the high-frequency signal to obtain a high-frequency amplitude signal;

[0032] The fault processor is used to determine whether there is a line fault based on the high-frequency amplitude signal, and if there is a line fault, locate the fault based on the high-frequency amplitude signal.

[0033] The embodiment of the present application collects electrical signals on the external line through the electrical quantity transformer of the intelligent circuit breaker, and can accurately identify the tiny electrical signals on the external line, which is convenient for subsequent accurate fault location through the intelligent circuit breaker; by filtering the power frequency signal in the electrical signal, the high-frequency signal containing abnormal discharge characteristics can be accurately retained, which is convenient for subsequent accurate fault location through the intelligent circuit breaker; by amplifying the amplitude of the high-frequency signal, the amplitude in the high-frequency signal can be amplified, which is convenient for subsequent processing and analysis, and helps to accurately locate the fault through the intelligent circuit breaker in the future; based on the high-frequency amplitude signal, it is judged whether there is a line fault, and the line fault judgment can be accurately performed based on the high-frequency amplitude signal. When there is a line fault, the intelligent circuit breaker can accurately locate the fault. Compared with the prior art, the present application can accurately identify tiny electrical signals, thereby realizing accurate fault location through the intelligent circuit breaker.

[0034] Furthermore, the intelligent circuit breaker further comprises: a judgment module, the judgment module comprising: an acquisition unit and a judgment unit;

[0035] The acquisition unit is used to acquire a time signal corresponding to the electrical signal;

[0036] The judgment unit is used to perform a protection action on the low-voltage distribution network based on the intelligent circuit breaker if the electrical signal is greater than a preset electrical threshold and the time signal exceeds a preset time threshold.

[0037] Further, the fault processor includes: a conversion unit and a positioning unit;

[0038] The conversion unit is used to convert the high-frequency amplitude signal with line fault into corresponding traveling wave data;

[0039] The positioning unit is used to obtain the timestamp of the traveling wave data from the fault point to the intelligent circuit breaker, determine the distance from the fault point to the intelligent circuit breakers at both ends based on the timestamp, and determine the fault point position of the low-voltage distribution network based on the distance.

[0040] Further, the positioning unit includes: a determination subunit, a receiving subunit and a calculation subunit;

[0041] The determination subunit is used to determine the first time when the traveling wave head reaches the intelligent circuit breaker from the fault point based on the traveling wave data;

[0042] The receiving subunit is used to receive the second time when the traveling wave header sent by the intelligent circuit breaker arranged at the other end of the line arrives at the intelligent circuit breaker arranged at the other end of the line from the fault point;

[0043] The calculation subunit is used to calculate the distance from the fault point to the intelligent circuit breaker and the distance from the intelligent circuit breaker at the other end based on the first time and the second time.

[0044] In a third aspect, the present application also provides a fault location system for a low-voltage distribution network, comprising at least two intelligent circuit breakers as described in the present application, wherein any two adjacent intelligent circuit breakers are respectively arranged at two ends of a corresponding external line. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 It is a flow chart of an embodiment of a method for locating a fault in a low-voltage distribution network provided by the present application;

[0046] Figure 2 yes Figure 1 Schematic diagram of the process of step S104;

[0047] Figure 3 This is a schematic diagram for calculating the distance from the fault point to the smart circuit breakers at both ends provided by this application;

[0048] Figure 4 It is a structural schematic diagram of an embodiment of the intelligent circuit breaker provided by the present application;

[0049] Figure 5 It is a structural schematic diagram of an embodiment of a fault location system for a low-voltage distribution network provided in the present application. DETAILED DESCRIPTION

[0050] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0051] It should be understood that the step numbers used in this article are only for the convenience of description and are not intended to limit the order in which the steps are executed.

[0052] It should be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, the singular forms "a", "an" and "the" are intended to include plural forms unless the context clearly indicates otherwise.

[0053] The terms “include” and “comprising” indicate the presence of described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0054] The term "and / or" means and includes any and all possible combinations of one or more of the associated listed items.

[0055] In recent years, with the increase in intelligent power distribution equipment, low-voltage intelligent molded case circuit breakers have become the key to low-voltage power distribution networks and bear the heavy responsibility of fault location. The current low-voltage distribution network mainly relies on power frequency signals for fault location, which has limited accuracy and the fault location is roughly determined to the area. In addition, the circuit breaker has a large working current and it is difficult to identify small current changes, which in turn affects the accuracy of fault location. Although some practices are to add branch circuit breakers to the branch boxes in the low-voltage area to achieve more detailed fault location, even so, the fault location can only be narrowed to the line level, which still cannot meet the high-precision requirements of low-voltage line fault location and increases costs.

[0056] Next, the nouns involved in this application are analyzed:

[0057] Artificial intelligence (AI) is a new technical science that studies and develops theories, methods, technologies and application systems for simulating, extending and expanding human intelligence. AI is a branch of computer science that attempts to understand the essence of intelligence and produce a new type of intelligent machine that can respond in a similar way to human intelligence. Research in this field includes robotics, speech recognition, image recognition, natural language processing and expert systems. AI can simulate the information process of human consciousness and thinking. AI is also a theory, method, technology and application system that uses digital computers or machines controlled by digital computers to simulate, extend and expand human intelligence, perceive the environment, acquire knowledge and use knowledge to obtain the best results.

[0058] Traveling wave ranging is a ranging method based on traveling wave theory. It uses the principle of signal emission and reflection to determine the length data between the target position and the starting and ending points by measuring the time difference between the traveling wave reaching each monitoring point.

[0059] Based on this, the embodiments of the present application provide a fault location method, an intelligent circuit breaker and a system for a low-voltage distribution network, which can accurately identify tiny electrical signals, and thus achieve accurate fault location through the intelligent circuit breaker.

[0060] A fault location method, intelligent circuit breaker and system for a low-voltage distribution network provided in an embodiment of the present application are specifically described through the following embodiments. First, the fault location method for a low-voltage distribution network in an embodiment of the present application is described.

[0061] The fault location method of the low-voltage distribution network provided in the embodiment of the present application relates to the field of fault location. The fault location method of the low-voltage distribution network provided in the embodiment of the present application can be applied to the terminal, can also be applied to the server side, and can also be software running in the terminal or the server side. In some embodiments, the terminal can be a smart phone, a tablet computer, a laptop computer, a desktop computer, etc.; the server side can be configured as an independent physical server, or it can be configured as a server cluster or a distributed system composed of multiple physical servers, and can also be configured as a cloud server that provides basic cloud computing services such as cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communications, middleware services, domain name services, security services, CDN, and big data and artificial intelligence platforms; the software can be an application that implements a fault location method for a low-voltage distribution network, etc., but is not limited to the above forms.

[0062] The present application can also be used in numerous general or special computer system environments or configurations. For example: personal computers, server computers, handheld or portable devices, tablet devices, multiprocessor systems, microprocessor-based systems, set-top boxes, programmable consumer electronics, network PCs, minicomputers, mainframe computers, distributed computing environments including any of the above systems or devices, etc. The present application can be described in the general context of computer executable instructions executed by a computer, such as program modules. Generally, program modules include routines, programs, objects, components, data structures, etc. that perform specific tasks or implement specific abstract data types. The present application can also be practiced in distributed computing environments, in which tasks are performed by remote processing devices connected through a communication network. In a distributed computing environment, program modules can be located in local and remote computer storage media including storage devices.

[0063] Embodiment 1

[0064] Please refer to Figure 1 , Figure 1 This is a flow chart of an embodiment of a fault location method for a low-voltage distribution network provided by the present application, which is applicable to an intelligent circuit breaker. The fault location method includes:

[0065] Step S101, collecting electrical signals on external lines through the electrical quantity transformer of the intelligent circuit breaker;

[0066] In some embodiments, it is necessary to first determine the amplitude range of the external line, the acquisition accuracy requirements, and sampling parameters such as the sampling rate. After the sampling parameters are determined, the electrical signal on the external line is acquired through the electrical quantity transformer according to the preset sampling parameters.

[0067] In some embodiments, the electrical quantity transformer includes a current transformer, a voltage transformer, etc. The current transformer can accurately capture the power frequency voltage signal and the high frequency current signal in the external circuit, and the voltage transformer can accurately capture the power frequency voltage signal and the high frequency voltage signal in the external circuit.

[0068] In some embodiments, the electrical signal includes an industrial frequency signal and a high frequency signal.

[0069] In some embodiments, in order to sample high-frequency signals, the sampling rate of the electrical quantity transformer needs to be greater than 10Mhz. At the same time, the sampling rate can meet the sampling requirements and restore the actual waveform of the external line, meeting the application scenarios of the low-voltage distribution network.

[0070] In some embodiments, the industrial frequency signal is typically a 50 Hz or 60 Hz power line base frequency signal.

[0071] In some embodiments, the high-frequency signal may include transient overvoltage, harmonics, high-frequency components generated by faults, etc., and the frequency range may be from kHz to MHz.

[0072] In some embodiments, before filtering out the power frequency signal in the electrical signal, it also includes: obtaining a time signal corresponding to the electrical signal; if the electrical signal is greater than a preset electrical threshold and the time signal exceeds the preset time threshold, then performing a protective action on the low-voltage distribution network based on the intelligent circuit breaker. Specifically, the specific time point at which the power signal occurs is obtained and the length of time for the occurrence is determined, and then the amplitude of the electrical signal is compared with the preset electrical threshold, and the time length is compared with the preset time length. If the amplitude of the electrical signal is greater than the preset electrical threshold, and the time length also exceeds the preset time threshold, it indicates that the electrical signal continues to be abnormal for a period of time, and it is considered that the system has a potential fault risk, and then the protection action of the intelligent circuit breaker will be automatically triggered.

[0073] In some embodiments, the protection action is divided into overcurrent protection and / or overvoltage protection, and the protection action may be but is not limited to cutting off the power supply of the fault area, sounding an alarm, notifying operation and maintenance personnel, etc.

[0074] It should be noted that the type of protection action will be determined comprehensively based on the nature and severity of the fault.

[0075] In some embodiments, the preset electrical threshold and the preset time threshold are usually reasonably set according to the specific conditions and operating experience of the low-voltage distribution network.

[0076] In this way, by performing protective actions on the low-voltage distribution network, the safe and stable operation of the power system can be ensured.

[0077] Step S102, filtering out the power frequency signal in the electrical signal and retaining the high frequency signal;

[0078] In some embodiments, after acquiring the electrical signal of the external circuit, since there are power frequency signals and high frequency signals in the electrical signal, and most abnormal discharges belong to high frequency signals, the power frequency signals in the electrical signal can be filtered out by a high-pass filter circuit or filter, but not limited to, to obtain a high frequency signal containing abnormal discharge characteristics. By filtering out the power frequency signals in the electrical signal, the problem of inaccurate fault location caused by full frequency domain waveform analysis of all electrical signals as in the prior art can be avoided.

[0079] In this way, by filtering out the industrial frequency signal in the electrical signal, the high frequency signal containing abnormal discharge characteristics can be accurately retained, which facilitates subsequent accurate fault location through the intelligent circuit breaker.

[0080] Step S103, amplifying the amplitude of the high-frequency signal to obtain a high-frequency amplitude signal;

[0081] In some embodiments, since the amplitude of the high-frequency signal is generally small, in order to ensure the strength and integrity of the high-frequency signal, it is necessary to amplify the amplitude of the high-frequency signal through an amplifier, repeater or amplification circuit to the required amplitude value without distortion, thereby obtaining a high-frequency amplitude signal.

[0082] In this way, by amplifying the amplitude of the high-frequency signal, the amplitude in the high-frequency signal can be amplified, which is convenient for subsequent processing and analysis, and helps to accurately locate the fault through the subsequent intelligent circuit breaker.

[0083] Step S104: judging whether there is a line fault based on the high-frequency amplitude signal, and if there is a line fault, locating the fault based on the high-frequency amplitude signal.

[0084] In some embodiments, based on experience or experimental data, one or more characteristic thresholds for determining faults are set, and the preprocessed high-frequency amplitude signal is compared with the set characteristic thresholds. If one or more characteristics of the signal exceed the characteristic thresholds, it is determined that a line fault exists.

[0085] In some embodiments, the characteristic threshold may be, but is not limited to, a specific characteristic of the high-frequency amplitude signal (eg, amplitude, frequency, phase, etc.).

[0086] Please refer to Figure 2 In some embodiments, if there is a line fault, the fault location is performed based on the high-frequency amplitude signal, including steps S201 to S202;

[0087] Step S201, converting the high-frequency amplitude signal of the line fault into corresponding traveling wave data; step S202, obtaining the timestamp of the traveling wave data from the fault point to the intelligent circuit breaker, determining the distance from the fault point to the intelligent circuit breakers at both ends based on the timestamp, and determining the fault point position of the low-voltage distribution network based on the distance.

[0088] In step S201 of some embodiments, after it is determined that there is a line fault, the high-frequency amplitude signal indicating the presence of the line fault is preprocessed, and a traveling wave component is extracted from the preprocessed signal using a signal processing technique to obtain traveling wave data.

[0089] In some embodiments, the signal processing technology may include, but is not limited to, wavelet transform, Fourier transform, and the like.

[0090] In some embodiments, the traveling wave data is formed when the electromagnetic wave generated by the fault propagates in the power line, and the waveform and characteristics of the traveling wave data can reflect the location and type of the fault.

[0091] In step S202 of some embodiments, the method includes: determining a first time when the wave head of the traveling wave reaches the intelligent circuit breaker from the fault point based on the traveling wave data; receiving a second time when the wave head of the traveling wave reaches the intelligent circuit breaker from the fault point to the intelligent circuit breaker at the other end of the line from the fault point sent by the intelligent circuit breaker at the other end of the line; and calculating the distance from the fault point to the intelligent circuit breaker and the distance from the intelligent circuit breaker at the other end based on the first time and the second time. Specifically, the intelligent circuit breaker M Apply wave head detection algorithms (such as threshold detection, wavelet transform, correlation analysis, etc.) to identify the arrival of the wave head. Once the wave head is detected, the intelligent circuit breaker M Immediately record the current timestamp as the first time t that the traveling wave head arrives M Similarly, the intelligent circuit breaker N will also detect the second time t when the wave head arrives N ; When determining the first time t M and the second time t N Afterwards, since the propagation speed v of the traveling wave data in the power line is known, based on the propagation speed v and the first time t M and the second time t N The fault point can be calculated to reach the intelligent circuit breaker M The distance from the intelligent circuit breaker N is L M and L N , when the distance from the fault point to the two ends of the intelligent circuit breaker (L M and L N), since the sum of the distances from the fault point to both ends is equal to the total length of the line, and the distance from the fault point to one end is equal to the total length of the line minus the distance corresponding to the time difference from that end to the other end where the wave head arrives, the specific location of the fault point can be calculated. The calculation diagram of the distance from the fault point to the intelligent circuit breakers at both ends is shown in the figure below: Figure 3 As shown in the figure, the distance from the fault point to the intelligent circuit breakers at both ends (L M and L N ) is calculated as follows:

[0092]

[0093] Where, L M and L N The fault point to the intelligent circuit breaker M and the distance between the intelligent circuit breaker N at the other end; L is the distance between the intelligent circuit breaker and the intelligent circuit breaker N at the other end; v is the propagation speed of the traveling wave data; t M For the fault point to the intelligent circuit breaker M The first time; N It is the second time from the fault point to the intelligent circuit breaker N at the other end.

[0094] In some embodiments, after the specific location of the fault point is determined, the location needs to be sent to the fault location main station through communication, and the operation and maintenance personnel or robots need to be reminded through text messages, emails, etc.

[0095] The embodiment of the present application collects electrical signals on the external line through the electrical quantity transformer of the intelligent circuit breaker, and can accurately identify the tiny electrical signals on the external line, which is convenient for subsequent accurate fault location through the intelligent circuit breaker; by filtering the power frequency signal in the electrical signal, the high-frequency signal containing abnormal discharge characteristics can be accurately retained, which is convenient for subsequent accurate fault location through the intelligent circuit breaker; by amplifying the amplitude of the high-frequency signal, the amplitude in the high-frequency signal can be amplified, which is convenient for subsequent processing and analysis, and helps to accurately locate the fault through the intelligent circuit breaker in the future; based on the high-frequency amplitude signal, it is judged whether there is a line fault, and the line fault judgment can be accurately performed based on the high-frequency amplitude signal. When there is a line fault, the intelligent circuit breaker can accurately locate the fault. Compared with the prior art, the present application can accurately identify tiny electrical signals, thereby realizing accurate fault location through the intelligent circuit breaker.

[0096] Embodiment 2

[0097] Please refer to Figure 4 , Figure 4It is a structural schematic diagram of an embodiment of the intelligent circuit breaker provided by the present application, comprising: an electrical quantity transformer 100, a high-pass filter module 200, an amplification module 300 and a fault processor 400;

[0098] The electrical quantity transformer 100 is used to collect electrical signals on external lines, wherein the electrical signals include power frequency signals and high frequency signals;

[0099] In some embodiments, it is necessary to first determine the amplitude range of the external line, the acquisition accuracy requirements, and sampling parameters such as the sampling rate. After the sampling parameters are determined, the electrical signal on the external line is acquired through the electrical quantity transformer according to the preset sampling parameters.

[0100] In some embodiments, the electrical quantity transformer includes a current transformer, a voltage transformer, etc. The current transformer can accurately capture the power frequency voltage signal and the high frequency current signal in the external circuit, and the voltage transformer can accurately capture the power frequency voltage signal and the high frequency voltage signal in the external circuit.

[0101] In some embodiments, in order to sample high-frequency signals, the sampling rate of the electrical quantity transformer needs to be greater than 10Mhz. At the same time, the sampling rate can meet the sampling requirements and restore the actual waveform of the external line, meeting the application scenarios of the low-voltage distribution network.

[0102] In some embodiments, the industrial frequency signal is typically a 50 Hz or 60 Hz power line base frequency signal.

[0103] In some embodiments, the high-frequency signal may include transient overvoltage, harmonics, high-frequency components generated by faults, etc., and the frequency range may be from kHz to MHz.

[0104] In some embodiments, the intelligent circuit breaker further includes: a judgment module, the judgment module includes: an acquisition unit and a judgment unit; the acquisition unit is used to acquire the time signal corresponding to the electrical signal; the judgment unit is used to perform a protective action on the low-voltage distribution network based on the intelligent circuit breaker if the electrical signal is greater than a preset electrical threshold and the time signal exceeds the preset time threshold. Specifically, the specific time point when the power signal occurs is acquired and the length of time when the power signal occurs is determined, and then the amplitude of the electrical signal is compared with the preset electrical threshold, and the time length is compared with the preset time length. If the amplitude of the electrical signal is greater than the preset electrical threshold, and the time length also exceeds the preset time threshold, it indicates that the electrical signal continues to be abnormal for a period of time, and it is considered that the system has a potential fault risk, and then the protection action of the intelligent circuit breaker will be automatically triggered.

[0105] In some embodiments, the protection action is divided into overcurrent protection and / or overvoltage protection, and the protection action may be but is not limited to cutting off the power supply of the fault area, sounding an alarm, notifying operation and maintenance personnel, etc.

[0106] It should be noted that the type of protection action will be determined comprehensively based on the nature and severity of the fault.

[0107] In some embodiments, the preset electrical threshold and the preset time threshold are usually reasonably set according to the specific conditions and operating experience of the low-voltage distribution network.

[0108] In this way, by performing protective actions on the low-voltage distribution network, the safe and stable operation of the power system can be ensured.

[0109] The high-pass filter module 200 is used to filter out the power frequency signal in the electrical signal and retain the high-frequency signal;

[0110] In some embodiments, after acquiring the electrical signal of the external circuit, since there are power frequency signals and high frequency signals in the electrical signal, and most abnormal discharges belong to high frequency signals, the power frequency signals in the electrical signal can be filtered out by a high-pass filter circuit or filter, but not limited to, to obtain a high frequency signal containing abnormal discharge characteristics. By filtering out the power frequency signals in the electrical signal, the problem of inaccurate fault location caused by full frequency domain waveform analysis of all electrical signals as in the prior art can be avoided.

[0111] In this way, by filtering out the industrial frequency signal in the electrical signal, the high frequency signal containing abnormal discharge characteristics can be accurately retained, which facilitates subsequent accurate fault location through the intelligent circuit breaker.

[0112] The amplification module 300 is used to amplify the amplitude of the high-frequency signal to obtain a high-frequency amplitude signal;

[0113] In some embodiments, since the amplitude of the high-frequency signal is generally small, in order to ensure the strength and integrity of the high-frequency signal, it is necessary to amplify the amplitude of the high-frequency signal through an amplifier, repeater or amplification circuit to the required amplitude value without distortion, thereby obtaining a high-frequency amplitude signal.

[0114] In this way, by amplifying the amplitude of the high-frequency signal, the amplitude in the high-frequency signal can be amplified, which is convenient for subsequent processing and analysis, and helps to accurately locate the fault through the subsequent intelligent circuit breaker.

[0115] The fault processor 400 is used to determine whether there is a line fault based on the high-frequency amplitude signal, and if there is a line fault, locate the fault based on the high-frequency amplitude signal.

[0116] In some embodiments, based on experience or experimental data, one or more characteristic thresholds for determining faults are set, and the preprocessed high-frequency amplitude signal is compared with the set characteristic thresholds. If one or more characteristics of the signal exceed the characteristic thresholds, it is determined that a line fault exists.

[0117] In some embodiments, the characteristic threshold may be, but is not limited to, a specific characteristic of the high-frequency amplitude signal (eg, amplitude, frequency, phase, etc.).

[0118] In some embodiments, the fault processor 400 includes: a conversion unit and a positioning unit; the conversion unit is used to convert the high-frequency amplitude signal of the line fault into corresponding traveling wave data; the positioning unit is used to obtain the timestamp of the traveling wave data from the fault point to the intelligent circuit breaker, determine the distance from the fault point to the intelligent circuit breakers at both ends based on the timestamp, and determine the fault point location of the low-voltage distribution network based on the distance. Specifically, after determining that there is a line fault, the high-frequency amplitude signal of the line fault is preprocessed, and the traveling wave component is extracted from the preprocessed signal using signal processing technology to obtain the traveling wave data.

[0119] In some embodiments, the signal processing technology may include, but is not limited to, wavelet transform, Fourier transform, and the like.

[0120] In some embodiments, the traveling wave data is formed when the electromagnetic wave generated by the fault propagates in the power line, and the waveform and characteristics of the traveling wave data can reflect the location and type of the fault.

[0121] In some embodiments, the positioning unit includes: a determining subunit, a receiving subunit and a calculating subunit; the determining subunit is used to determine the first time when the traveling wave head reaches the intelligent circuit breaker from the fault point based on the traveling wave data; the receiving subunit is used to receive the second time when the traveling wave head sent by the intelligent circuit breaker at the other end of the line reaches the intelligent circuit breaker at the other end of the line from the fault point; the calculating subunit is used to calculate the distance from the fault point to the intelligent circuit breaker and the distance from the other end to the intelligent circuit breaker based on the first time and the second time. Specifically, the intelligent circuit breaker M Apply wave head detection algorithms (such as threshold detection, wavelet transform, correlation analysis, etc.) to identify the arrival of the wave head. Once the wave head is detected, the intelligent circuit breaker M Immediately record the current timestamp as the first time t that the traveling wave head arrives M Similarly, the intelligent circuit breaker N will also detect the second time t when the wave head arrives N ; When determining the first time t M and the second time t NAfterwards, since the propagation speed v of the traveling wave data in the power line is known, based on the propagation speed v and the first time t M and the second time t N The fault point can be calculated to reach the intelligent circuit breaker M The distance from the intelligent circuit breaker N is L M and L N , when the distance from the fault point to the two ends of the intelligent circuit breaker (L M and L N ), since the sum of the distances from the fault point to both ends is equal to the total length of the line, and the distance from the fault point to one end is equal to the total length of the line minus the distance corresponding to the time difference from that end to the other end where the wave head arrives, the specific location of the fault point can be calculated. The calculation diagram of the distance from the fault point to the intelligent circuit breakers at both ends is shown in the figure below: Figure 3 As shown in the figure, the distance from the fault point to the intelligent circuit breakers at both ends (L M and L N ) is calculated as follows:

[0122]

[0123] Where, L M and L N The fault point to the intelligent circuit breaker M and the distance between the intelligent circuit breaker N at the other end; L is the distance between the intelligent circuit breaker and the intelligent circuit breaker N at the other end; v is the propagation speed of the traveling wave data; t M For the fault point to the intelligent circuit breaker M The first time; N It is the second time from the fault point to the intelligent circuit breaker N at the other end.

[0124] In some embodiments, after the specific location of the fault point is determined, the location needs to be sent to the fault location main station through communication, and the operation and maintenance personnel or robots need to be reminded through text messages, emails, etc.

[0125] The embodiment of the present application collects electrical signals on the external line through the electrical quantity transformer of the intelligent circuit breaker, and can accurately identify the tiny electrical signals on the external line, which is convenient for subsequent accurate fault location through the intelligent circuit breaker; by filtering the power frequency signal in the electrical signal, the high-frequency signal containing abnormal discharge characteristics can be accurately retained, which is convenient for subsequent accurate fault location through the intelligent circuit breaker; by amplifying the amplitude of the high-frequency signal, the amplitude in the high-frequency signal can be amplified, which is convenient for subsequent processing and analysis, and helps to accurately locate the fault through the intelligent circuit breaker in the future; based on the high-frequency amplitude signal, it is judged whether there is a line fault, and the line fault judgment can be accurately performed based on the high-frequency amplitude signal. When there is a line fault, the intelligent circuit breaker can accurately locate the fault. Compared with the prior art, the present application can accurately identify tiny electrical signals, thereby realizing accurate fault location through the intelligent circuit breaker.

[0126] Embodiment 3

[0127] Please refer to Figure 5 , Figure 5 It is a structural schematic diagram of an embodiment of a fault location system for a low-voltage distribution network provided by the present application, wherein the system includes at least two intelligent circuit breakers, wherein any two adjacent intelligent circuit breakers are respectively arranged at the two ends of the corresponding external line, and for any intelligent circuit breaker, it includes: an electrical quantity transformer, a high-pass filtering module, an amplification module and a fault processor.

[0128] The device embodiments described above are merely illustrative, wherein the modules described as separate components may or may not be physically separated, i.e., may be located in one place, or may be distributed to multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the method of this embodiment.

[0129] A person skilled in the art can understand that all or part of the processes in the above-mentioned embodiments can be implemented by instructing the relevant hardware through a computer program, and the program can be stored in a computer-monitorable storage medium, and when the program is executed, it can include the processes of the embodiments of the above-mentioned methods. The storage medium can be a disk, an optical disk, a read-only memory (ROM) or a random access memory (RAM), etc.

[0130] The specific embodiments described above further illustrate the purpose, technical solutions and beneficial effects of the present application in detail. It should be understood that the above description is only a specific embodiment of the present application and is not intended to limit the scope of protection of the present application.

[0131] It is particularly pointed out that for those skilled in the art, any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of this application should be included in the protection scope of this application.

Claims

1. A fault location method for a low voltage distribution network, characterized in that: Applicable to intelligent circuit breakers, the fault location method includes: Collecting electrical signals on external lines through the electrical quantity transformer of the intelligent circuit breaker; filtering out the power frequency signal in the electrical signal and retaining the high frequency signal; amplifying the amplitude of the high-frequency signal to obtain a high-frequency amplitude signal; Based on the high-frequency amplitude signal, it is determined whether there is a line fault. If there is a line fault, the fault is located based on the high-frequency amplitude signal.

2. The fault location method of the low voltage distribution network according to claim 1, characterized in that: Before filtering out the power frequency signal in the electrical signal, the method further includes: Acquire a time signal corresponding to the electrical signal; If the electrical signal is greater than a preset electrical threshold and the time signal exceeds a preset time threshold, a protection action is performed on the low-voltage distribution network based on the intelligent circuit breaker.

3. The fault location method of the low voltage distribution network according to claim 1, characterized in that: If there is a line fault, the fault location is performed based on the high-frequency amplitude signal, specifically: Converting the high frequency amplitude signal of the line fault into corresponding traveling wave data; Obtain the timestamp of the traveling wave data from the fault point to the intelligent circuit breaker, determine the distance from the fault point to the intelligent circuit breakers at both ends based on the timestamp, and determine the fault point location of the low-voltage distribution network based on the distance.

4. The fault location method of the low voltage distribution network according to claim 3, characterized in that: The obtaining of the timestamp of the traveling wave data from the fault point to the intelligent circuit breaker, and determining the distance from the fault point to the intelligent circuit breakers at both ends based on the timestamp, is specifically: Determine the first time when the traveling wave head reaches the intelligent circuit breaker from the fault point based on the traveling wave data; Receiving a second time when the traveling wave header sent by the intelligent circuit breaker arranged at the other end of the line arrives at the intelligent circuit breaker arranged at the other end of the line from the fault point; The distances from the fault point to the intelligent circuit breaker and the distance from the intelligent circuit breaker at the other end are calculated based on the first time and the second time.

5. The fault location method of the low voltage distribution network according to claim 4, characterized in that: The calculation formula for respectively calculating the distance from the fault point to the intelligent circuit breaker and the distance from the intelligent circuit breaker at the other end based on the first time and the second time is specifically: Where, L M and L N The fault point to the intelligent circuit breaker M and the distance between the intelligent circuit breaker N at the other end; L is the distance between the intelligent circuit breaker and the intelligent circuit breaker N at the other end; v is the propagation speed of the traveling wave data; t M For the fault point to the intelligent circuit breaker M The first time; N It is the second time from the fault point to the intelligent circuit breaker N at the other end.

6. An intelligent circuit breaker, characterized in that: include: Electrical quantity transformer, high-pass filter module, amplifier module and fault processor; The electrical quantity transformer is used to collect electrical signals on external lines, wherein the electrical signals include power frequency signals and high frequency signals; The high-pass filter module is used to filter out the power frequency signal in the electrical signal and retain the high-frequency signal; The amplification module is used to amplify the amplitude of the high-frequency signal to obtain a high-frequency amplitude signal; The fault processor is used to determine whether there is a line fault based on the high-frequency amplitude signal, and if there is a line fault, locate the fault based on the high-frequency amplitude signal.

7. The intelligent circuit breaker according to claim 6, characterized in that: Also includes: A judgment module, the judgment module comprising: an acquisition unit and a judgment unit; The acquisition unit is used to acquire a time signal corresponding to the electrical signal; The judgment unit is used to perform a protection action on the low-voltage distribution network based on the intelligent circuit breaker if the electrical signal is greater than a preset electrical threshold and the time signal exceeds a preset time threshold.

8. The intelligent circuit breaker according to claim 6, characterized in that: The fault processor comprises: a conversion unit and a positioning unit; The conversion unit is used to convert the high-frequency amplitude signal with line fault into corresponding traveling wave data; The positioning unit is used to obtain the timestamp of the traveling wave data from the fault point to the intelligent circuit breaker, determine the distance from the fault point to the intelligent circuit breakers at both ends based on the timestamp, and determine the fault point position of the low-voltage distribution network based on the distance.

9. The intelligent circuit breaker according to claim 8, characterized in that: The positioning unit includes: a determination subunit, a receiving subunit and a calculation subunit; The determination subunit is used to determine the first time when the traveling wave head reaches the intelligent circuit breaker from the fault point based on the traveling wave data; The receiving subunit is used to receive the second time when the traveling wave header sent by the intelligent circuit breaker arranged at the other end of the line arrives at the intelligent circuit breaker arranged at the other end of the line from the fault point; The calculation subunit is used to calculate the distance from the fault point to the intelligent circuit breaker and the distance from the intelligent circuit breaker at the other end based on the first time and the second time.

10. A fault location system for a low voltage distribution network, characterized in that: It comprises at least two intelligent circuit breakers as claimed in any one of claims 6 to 9, wherein any two adjacent intelligent circuit breakers are respectively arranged at two ends of the corresponding external lines.

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