A method and system for low-voltage coordinated state sensing in power distribution networks

Abstract

This invention discloses a method and system for low-voltage coordinated status sensing in a distribution network. Within each analysis cycle, it acquires electrical quantity information of the medium- and low-voltage sides of the distribution network within a preset frequency range; it determines whether harmonic quantities fluctuate in adjacent analysis cycles; if fluctuations occur, it determines that the electrical quantity information of the medium-voltage side and / or low-voltage side is abnormal; it sends characteristic power line carrier sensing signals to the medium-voltage side and / or low-voltage side with abnormal electrical quantity information; when it receives the characteristic power line carrier sensing signals reflected back from the power line, it performs feature extraction and parameter analysis on the transmitted and received characteristic power line carrier sensing signals, and sends the analysis results to the coordinated monitoring software functional module. The coordinated monitoring software functional module compares the analysis results with preset signal features in the equipment status feature database; when the analysis results are abnormal, it locates the medium- and low-voltage coordinated sensing terminal based on its address.

Description

[0001] This application claims priority to the earlier application filed on June 21, 2021, with application number 2021106829386, entitled "A Low-Voltage Cooperative Status Sensing Method and Device in a Distribution Network", the entire contents of which are set forth in this application. Technical Field

[0002] This invention relates to the field of power systems and their automation technology, specifically to a low-voltage collaborative state sensing method and system in a distribution network. Background Technology

[0003] Medium and low voltage distribution network equipment includes distribution transformers, distribution switches, and distribution cables. These components are numerous and widely distributed, resulting in a large workload for operation and maintenance, and a relatively low level of lean management. Currently, condition monitoring of medium and low voltage distribution network equipment is not widely applied due to the high cost of condition sensing. Equipment maintenance is mainly based on fault diagnosis, meaning that when a fault causes a power outage, the electricity user notifies the power company, which then organizes the search and handling of the fault after receiving the outage information. This passive repair mode is inefficient and has a long fault recovery time. There is an urgent need to combine intelligent sensing and power Internet of Things (IoT) technologies to promote a shift in distribution network operation and maintenance from passive repair to proactive maintenance.

[0004] To address fault monitoring issues, power companies typically deploy distribution automation systems, which primarily monitor low-frequency (generally less than 2kHz) electrical quantities (voltage and current). Over the years, monitoring of non-electrical quantities (temperature, humidity, water immersion, door sensors, etc.) in distribution equipment and facilities has been gradually implemented to achieve awareness of the distribution status. Overall, current solutions still have some limitations in providing deep awareness of the status of online equipment.

[0005] 1. Lack of wideband electrical quantity (voltage coverage at least DC-20kHz, current coverage at least DC-1MHz) information collection;

[0006] 2. Without combining active injection signal feature analysis, the reliability of broadband electrical quantity anomaly identification is low;

[0007] 3. In the current solution, the distribution transformer monitoring terminal generally only collects electrical quantity signals on the low-voltage side and cannot collect electrical quantity signals on the medium-voltage side, thus failing to support the coordinated monitoring of medium and low voltage.

[0008] 4. The application of non-electrical quantity sensors in power distribution networks is costly and difficult to promote. Summary of the Invention

[0009] Therefore, the technical problem to be solved by the present invention is to overcome the defect that the existing distribution transformer monitoring terminal cannot support the coordinated monitoring of medium and low voltage, thereby providing a method and system for sensing the coordinated status of medium and low voltage in the distribution network.

[0010] To achieve the above objectives, the present invention provides the following technical solution:

[0011] In a first aspect, embodiments of the present invention provide a method for low-voltage coordinated state perception in a distribution network, applied to a low-voltage coordinated perception terminal. The method includes: acquiring electrical quantity information of the medium-voltage side and low-voltage side of the distribution network in real time within a preset frequency range during each analysis cycle; determining whether harmonic quantities fluctuate in adjacent analysis cycles; when harmonic quantities fluctuate in the current analysis cycle, determining that the electrical quantity information of the medium-voltage side and / or low-voltage side of the distribution network is abnormal; sending a characteristic power line carrier sensing signal to the medium-voltage side and / or low-voltage side with abnormal electrical quantity information, the characteristic power line carrier sensing signal being coupled to the power line; when the characteristic power line carrier sensing signal reflected back from the power line is received, performing feature extraction and parameter analysis on the sent and received characteristic power line carrier sensing signals, and sending the analysis results to the coordinated monitoring software functional module.

[0012] In one embodiment, the low-voltage collaborative state perception method in the distribution network further includes: sending the signal features obtained by extracting features from the transmitted characteristic power line carrier sensing signal to the collaborative monitoring software functional module.

[0013] In one embodiment, the electrical quantity information includes three-phase voltage and three-phase current.

[0014] In one embodiment, the process of determining whether harmonic quantities fluctuate between adjacent analysis cycles includes: for each analysis cycle, performing spectrum analysis on the three-phase voltage and three-phase current to obtain harmonic voltage and harmonic current; for each analysis cycle, calculating the energy and content of even-order harmonic voltages of a specific order based on the harmonic voltage, and calculating the energy and content of even-order harmonic currents of a specific order based on the harmonic current; subtracting the energy and content of even-order harmonic voltages of a specific order in the current analysis cycle from the energy and content of even-order harmonic voltages of a specific order in the previous analysis cycle to obtain voltage energy difference and voltage content difference; subtracting the energy and content of even-order harmonic currents of a specific order in the current analysis cycle from the energy and content of even-order harmonic currents of a specific order in the previous analysis cycle to obtain current energy difference and current content difference; determining whether the absolute values ​​of voltage energy difference and voltage content difference, and the absolute values ​​of current energy difference and current content difference, respectively, correspond to preset thresholds; when at least one absolute value exceeds the corresponding preset threshold, it is determined that the harmonic quantities of the current analysis cycle fluctuate.

[0015] In one embodiment, the low-voltage coordinated state sensing method in the distribution network further includes: when a characteristic power line carrier sensing signal is received from a low-voltage coordinated sensing terminal that performs the sending function, the signal characteristics of the characteristic power line carrier sensing signal are fed back to the coordinated monitoring software function module.

[0016] Secondly, embodiments of the present invention provide a method for sensing the coordinated status of low-voltage distribution networks, applied to a coordinated monitoring software functional module. The method includes: comparing the analysis results sent by the low-voltage coordinated sensing terminal with preset signal features in the equipment status feature database; when the analysis results are abnormal, locating the low-voltage coordinated sensing terminal based on its address.

[0017] In one embodiment, the low-voltage coordinated status sensing method in the distribution network further includes: comparing the signal characteristics sent by the low-voltage coordinated sensing terminal performing the transmitting function and the signal characteristics sent by the corresponding low-voltage coordinated sensing terminal performing the receiving function with preset signal characteristics in the equipment status characteristic database; when the signal characteristics are abnormal, locating the low-voltage coordinated sensing terminal based on the address of the low-voltage coordinated sensing terminal with the abnormal transmitting signal characteristics.

[0018] Thirdly, embodiments of the present invention provide a low-voltage coordinated state sensing system for a distribution network, comprising: a coordinated monitoring software functional module and a low-voltage coordinated sensing terminal, wherein the low-voltage coordinated sensing terminal is connected across the medium-voltage side and the low-voltage side of a transformer in the distribution network; the low-voltage coordinated sensing terminal is used to execute the low-voltage coordinated state sensing method for a distribution network according to the first aspect; the coordinated monitoring software functional module is connected to the low-voltage coordinated sensing terminal; the coordinated monitoring software functional module is used to execute the low-voltage coordinated state sensing method for a distribution network according to the second aspect.

[0019] In one embodiment, the medium- and low-voltage collaborative sensing terminal includes: a central processing unit module, a remote communication module, an acquisition module, and a signal transceiver module. The acquisition module is used to acquire electrical quantity information of the medium-voltage and low-voltage sides of the distribution network within a preset frequency range in real time during each analysis cycle. The central processing unit module is connected to the acquisition module and the signal transceiver module, and is also connected to the collaborative monitoring software function module via the remote communication module. The central processing unit module is used to determine whether harmonic quantities fluctuate in adjacent analysis cycles. When harmonic quantities fluctuate in the current analysis cycle, it determines that the electrical quantity information of the medium-voltage side and / or low-voltage side of the distribution network is abnormal. It sends characteristic power line carrier sensing signals to the medium-voltage side and / or low-voltage side with abnormal electrical quantity information via the signal transceiver module. It receives the characteristic power line carrier sensing signals reflected back from the power lines via the signal transceiver module, performs feature extraction and parameter analysis on the received characteristic power line carrier sensing signals, and sends the analysis results to the collaborative monitoring software function module.

[0020] The technical solution of this invention has the following advantages:

[0021] The present invention provides a method and system for coordinating the status of medium and low voltage distribution networks. In each analysis cycle, it acquires electrical quantity information of the medium-voltage and low-voltage sides of the distribution network within a preset frequency range in real time. It determines whether harmonic quantities fluctuate in adjacent analysis cycles. When harmonic quantities fluctuate in the current analysis cycle, it determines that the electrical quantity information of the medium-voltage and / or low-voltage sides of the distribution network is abnormal. It sends a characteristic power line carrier sensing signal to the medium-voltage and / or low-voltage sides with abnormal electrical quantity information, and the characteristic power line carrier sensing signal is coupled to the power line. When the characteristic power line carrier sensing signal reflected back from the power line is received, feature extraction and parameter analysis are performed on the transmitted and received characteristic power line carrier sensing signals, and the analysis results are sent to the collaborative monitoring software functional module. The analysis results sent by the medium- and low-voltage collaborative sensing terminal are compared with preset signal features in the equipment status feature database. When the analysis results are abnormal, the medium- and low-voltage collaborative sensing terminal is located based on its address. Attached Figure Description

[0022] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0023] Figure 1 A composition diagram of a specific example of a low-voltage coordinated state sensing system in a power distribution network provided in an embodiment of the present invention;

[0024] Figure 2 This is a flowchart illustrating a specific example of the low-voltage coordinated state sensing method in a distribution network according to an embodiment of the present invention.

[0025] Figure 3 This is a flowchart illustrating another specific example of the low-voltage coordinated state sensing method in a distribution network according to an embodiment of the present invention;

[0026] Figure 4 This is a flowchart illustrating another specific example of the low-voltage coordinated state sensing method in a distribution network according to an embodiment of the present invention;

[0027] Figure 5 This is a flowchart illustrating another specific example of the low-voltage coordinated state sensing method in a distribution network according to an embodiment of the present invention;

[0028] Figure 6A composition diagram of another specific example of a low-voltage coordinated state sensing system in a power distribution network provided in an embodiment of the present invention;

[0029] Figure 7 This is a composition diagram of another specific example of a low-voltage coordinated state sensing system in a power distribution network provided in an embodiment of the present invention. Detailed Implementation

[0030] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0032] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can also refer to the internal connection of two components; and they can refer to a wireless connection or a wired connection. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0033] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0034] Example 1

[0035] This invention provides a low-voltage coordinated status sensing method for distribution networks, which comprises, as follows: Figure 1 The sensing system shown comprises a low-voltage collaborative sensing terminal 1 and a collaborative monitoring software module 2. This embodiment of the invention applies to the low-voltage collaborative sensing terminal, such as... Figure 2 As shown, the method includes:

[0036] Step S11: In each analysis cycle, the electrical quantity information of the medium-voltage side and low-voltage side of the distribution network within the preset frequency range is acquired in real time.

[0037] Specifically, when the low-voltage collaborative sensing terminal receives the start acquisition command from the collaborative monitoring software function module, the low-voltage collaborative sensing terminal starts the acquisition of low-voltage broadband electrical quantity information, and acquires the electrical quantity information of the medium-voltage side and the electrical quantity information of the low-voltage side in parallel. The electrical quantity information includes: three-phase voltage and three-phase current, namely, medium-voltage side voltage and current, and low-voltage side voltage and current.

[0038] Step S12: Determine whether the harmonic quantity fluctuates in adjacent analysis cycles. When the harmonic quantity fluctuates in the current analysis cycle, determine that the electrical quantity information of the medium-voltage side and / or low-voltage side of the distribution network is abnormal.

[0039] Specifically, the medium- and low-voltage collaborative sensing terminal determines in real time whether the harmonic quantity fluctuates in the current analysis cycle. When fluctuation occurs, it directly determines that the electrical quantity information of the medium-voltage side and / or low-voltage side of the distribution network collected in the current analysis cycle is abnormal; otherwise, it returns to step S11 to continue collecting and analyzing. In this embodiment of the invention, the medium- and low-voltage collaborative sensing terminal can analyze the abnormal analysis cycle of medium- and low-voltage broadband electrical quantity information according to two power frequency voltage cycles. Based on the identification of voltage zero crossing points, it analyzes the voltage and current information after differential analysis of the two cycles. Figure 3 As shown, the judgment process is executed from steps S21 to S25, as follows:

[0040] Step S21: For each analysis cycle, perform spectrum analysis on the three-phase voltage and three-phase current to obtain harmonic voltage and harmonic current; the spectrum analysis is not limited to the Fourier transform method and is not restricted here.

[0041] Step S22: For each analysis cycle, based on the harmonic voltage, calculate the energy and content of the even-order harmonic voltage of a specific order, and based on the harmonic current, calculate the energy and content of the even-order harmonic current of a specific order.

[0042] Step S23: Subtract the energy and content of the even-order harmonic voltage of a specific order in the current analysis cycle from the energy and content of the even-order harmonic voltage of a specific order in the previous analysis cycle to obtain the voltage energy difference and voltage content difference; Subtract the energy and content of the even-order harmonic current of a specific order in the current analysis cycle from the energy and content of the even-order harmonic current of a specific order in the previous analysis cycle to obtain the current energy difference and current content difference.

[0043] Specifically, the energy and content of even-order harmonic voltage and current at a specific order in the previous analysis period (k-1 period) and the current analysis period (k period) are calculated separately. The energy and content of the even-order harmonic voltage at a specific order obtained in the k-1 period and the k period are then differentiated to obtain the voltage and current energy difference and the current content difference. For example, calculating the even-order harmonic content from 2 to 400, in a power grid with a fundamental frequency of 50Hz, specifically the harmonic content and energy at 100Hz, 200Hz, ..., 20kHz. The formulas for calculating the harmonic content and energy are shown below:

[0044]

[0045]

[0046] In the formula, RM H For harmonic content, H D Harmonic content, H2, H4, ..., H 400 H1 represents the effective values ​​of the even harmonics from the 2nd to the 400th, and H2 represents the effective value of the fundamental frequency.

[0047] Step S24: Determine whether the absolute values ​​of voltage energy difference and voltage content difference, and the absolute values ​​of current energy difference and current content difference correspond to the preset thresholds respectively;

[0048] Step S25: When at least one absolute value exceeds the corresponding preset threshold, it is determined that the harmonic quantity of the current analysis period fluctuates.

[0049] Specifically, if the absolute value of the voltage energy difference on the medium-voltage side and / or the absolute value of the voltage content difference on the medium-voltage side exceeds a preset threshold, it is determined that the harmonic quantity on the medium-voltage side is fluctuating and the electrical quantity information on the medium-voltage side is abnormal; if the absolute value of the voltage energy difference on the low-voltage side and / or the absolute value of the voltage content difference on the low-voltage side exceeds a preset threshold, it is determined that the harmonic quantity on the low-voltage side is fluctuating and the electrical quantity information on the low-voltage side is abnormal.

[0050] Step S13: Send a characteristic power line carrier sensing signal to the medium-voltage side and / or low-voltage side where the electrical quantity information is abnormal, and the characteristic power line carrier sensing signal is coupled to the power line;

[0051] Specifically, when the electrical quantity information on the medium-voltage side is abnormal, the medium- and low-voltage collaborative sensing terminal sends a characteristic power line carrier sensing signal to the medium-voltage side; when the electrical quantity information on the low-voltage side is abnormal, the medium- and low-voltage collaborative sensing terminal sends a characteristic power line carrier sensing signal to the low-voltage side. The characteristic power line carrier sensing signal has specific transmission power, phase, amplitude, and the number of orthogonal power line carrier sensing signals. The characteristic power line carrier sensing signal is coupled to the power line, and the signal coupler can be an inductive coupler or a capacitive coupler.

[0052] Specifically, based on actual operating conditions, the frequency band of the characteristic power line carrier sensing signal in this embodiment of the invention covers at least 20kHz to 30MHz, excluding 20kHz, and adopts orthogonal frequency division multiplexing modulation. Furthermore, to avoid the frequency bands currently used for power line carrier communication when transmitting the signal, the frequency bands to be avoided include: firstly, statically configuring to avoid the frequency bands currently used by the power company's automatic meter reading; and secondly, dynamically detecting and identifying the communication signals on the power line before transmitting the signal, and automatically adjusting the frequency of the orthogonal power line carrier sensing signal based on the identification results.

[0053] Step S14: When the characteristic power line carrier sensing signal reflected back from the power line is received, feature extraction and parameter analysis are performed on the transmitted and received characteristic power line carrier sensing signals, and the analysis results are sent to the collaborative monitoring software function module.

[0054] Specifically, when a characteristic power line carrier sensing signal is sent to the medium-voltage side and / or low-voltage side where electrical quantity information is abnormal, the characteristic power line carrier sensing signal is coupled to the power line. The impedance transformation node on the power line will reflect the characteristic power line carrier sensing signal back to the medium- and low-voltage collaborative sensing terminal. The medium- and low-voltage collaborative sensing terminal analyzes the transmitted and received characteristic power line carrier sensing signals in terms of parameters such as time delay, energy attenuation, and phase delay, and the identification results are fed back to the collaborative monitoring software functional module.

[0055] In one specific embodiment, the low-voltage coordinated state sensing method in the distribution network further includes:

[0056] After the medium- and low-voltage collaborative sensing terminal sends the characteristic power line carrier sensing signal, it extracts the signal features from the sent characteristic power line carrier sensing signal and sends them to the collaborative monitoring software function module.

[0057] When a characteristic power line carrier sensing signal is received from a medium- or low-voltage collaborative sensing terminal that performs the corresponding transmission function, the signal characteristics of the characteristic power line carrier sensing signal are fed back to the collaborative monitoring software function module.

[0058] Specifically, when the characteristic power line carrier sensing signal is not reflected back to the medium- and low-voltage collaborative sensing terminal from the power line impedance transformation point, but is instead transmitted from the power line to another medium- and low-voltage collaborative sensing terminal, for example: medium- and low-voltage collaborative sensing terminal #1 transmits the characteristic power line carrier sensing signal, the characteristic power line carrier sensing signal is coupled to the power line, and the characteristic power line carrier sensing signal is transmitted to medium- and low-voltage collaborative sensing terminal #2 through the power line, then medium- and low-voltage collaborative sensing terminal #1 needs to feed back the signal characteristics of the transmitted characteristic power line carrier sensing signal to the collaborative monitoring software function module, and medium- and low-voltage collaborative sensing terminal #2 needs to feed back the signal characteristics of the received characteristic power line carrier sensing signal to the collaborative monitoring software function module.

[0059] Example 2

[0060] This invention provides a low-voltage collaborative status sensing method for distribution networks, applied to collaborative monitoring software functional modules, such as... Figure 4 As shown, the method includes:

[0061] Step S31: Compare the analysis results sent by the medium and low voltage collaborative sensing terminal with the preset signal features in the equipment status feature database;

[0062] Specifically, when the power line reflects the characteristic power line carrier sensing signal back to the medium- and low-voltage collaborative sensing terminal, and when the collaborative monitoring software functional module receives the analysis results obtained from steps S11 to S14, it compares the analysis results sent by the medium- and low-voltage collaborative sensing terminal with the preset signal characteristics in the equipment status characteristic database. The analysis results may include parameters such as time delay, energy attenuation, and phase delay between the transmitted and received characteristic power line carrier sensing signals, or the signal characteristics of the transmitted and received characteristic power line carrier sensing signals. The collaborative monitoring software functional module compares the signal characteristics of the transmitted and received signals with the preset signal characteristics in the equipment status characteristic database. If the signal characteristics or parameters do not meet the requirements of the preset signal characteristics, the analysis result is determined to be abnormal.

[0063] Step S32: When the analysis result is abnormal, locate the medium- and low-voltage collaborative sensing terminal based on its address.

[0064] In one specific embodiment, such as Figure 5 As shown, the low-voltage coordinated state sensing method in the distribution network also includes:

[0065] Step S41: Compare the signal characteristics sent by the medium- and low-voltage collaborative sensing terminal performing the sending function and the corresponding signal characteristics sent by the medium- and low-voltage collaborative sensing terminal performing the receiving function with the preset signal characteristics in the device status feature database.

[0066] Step S42: When the signal characteristics are abnormal, locate the medium- and low-voltage collaborative sensing terminal based on the address of the medium- and low-voltage collaborative sensing terminal that transmits abnormal signal characteristics.

[0067] Specifically, when the power line does not reflect the characteristic power line carrier sensing signal back to the low-voltage collaborative sensing terminal, but instead sends it to another low-voltage collaborative sensing terminal—for example, if low-voltage collaborative sensing terminal #1 transmits the characteristic power line carrier sensing signal, the characteristic power line carrier sensing signal is coupled to the power line, and the characteristic power line carrier sensing signal is sent to low-voltage collaborative sensing terminal #2 via the power line—then low-voltage collaborative sensing terminal #1 needs to feed back the signal characteristics of the transmitted characteristic power line carrier sensing signal to the collaborative monitoring software function module, and low-voltage collaborative sensing terminal #2 needs to feed back the signal characteristics of the received characteristic power line carrier sensing signal to the collaborative monitoring software function module. The collaborative monitoring software function module then compares the signal characteristics sent by both low-voltage collaborative sensing terminals #1 and #2 with the preset signal characteristics in the equipment status characteristic database.

[0068] Example 3

[0069] This invention provides a low-voltage coordinated state sensing system for distribution networks, such as... Figure 6 As shown, it includes: a medium- and low-voltage collaborative sensing terminal 1 and a collaborative monitoring software functional module 2, wherein...

[0070] like Figure 1 As shown, the medium- and low-voltage collaborative sensing terminal 1 is connected across the medium-voltage side and the low-voltage side of the transformer in the distribution network; the medium- and low-voltage collaborative sensing terminal 1 is used to execute the distribution network medium- and low-voltage collaborative state sensing method of Embodiment 1, which will not be described in detail here.

[0071] like Figure 1 As shown, the collaborative monitoring software function module 2 is connected to the medium and low voltage collaborative sensing terminal 1; the collaborative monitoring software function module 2 is used to execute the distribution network medium and low voltage collaborative status sensing method of Embodiment 2, which will not be described in detail here.

[0072] In one specific embodiment, such as Figure 7 As shown, the medium- and low-voltage collaborative sensing terminal 1 includes: a central processing unit module 11, a remote communication module 12, an acquisition module 13, and a signal transceiver module 14. The remote communication module 12 adopts the existing communication network of the power company, which may include wireless public network, wireless private network, power line carrier communication, fiber optic communication, etc. The communication protocol supports IEC 104, MQTT, COAP and other protocols.

[0073] Specifically, the acquisition module 13 is used to acquire electrical quantity information of the medium-voltage side and low-voltage side of the distribution network within a preset frequency range in real time during each analysis cycle; the medium-voltage broadband electrical quantity information includes the medium-voltage A, B, and C three-phase currents I MA I MB I MC The current signal acquisition frequency band covers DC-1MHz; the medium voltage A, B, and C three-phase voltages U are acquired. MA U MB U MC The voltage signal acquisition frequency band covers DC-20kHz. The sensors used for current signal acquisition are not limited to one or a combination of electromagnetic current transformers, Rogowski coils, electronic current transformers, and novel magnetoresistive current transformers; low-voltage broadband electrical quantity information includes the acquisition of low-voltage A, B, and C phase currents I... LA I LB I LC The current signal acquisition frequency band covers DC-1MHz; it acquires the low-voltage A, B, and C three-phase voltages U. LA U LB U LC The voltage signal acquisition frequency band covers DC-20kHz. The sensors used for voltage signal acquisition are not limited to one or a combination of electromagnetic voltage transformers and electronic voltage transformers.

[0074] Specifically, the central processing unit module 11 is connected to the acquisition module 13 and the signal transceiver module 14, and the central processing unit module 11 is also connected to the collaborative monitoring software function module 2 through the remote communication module 12;

[0075] The central processing unit module 11 can implement the relevant methods involved in Embodiments 1 and 2. Specifically, it can be used to determine whether the harmonic quantity of adjacent analysis cycles fluctuates. When the harmonic quantity of the current analysis cycle fluctuates, it determines that the electrical quantity information of the medium-voltage side and / or low-voltage side of the distribution network is abnormal. It sends a characteristic power line carrier sensing signal to the medium-voltage side and / or low-voltage side with abnormal electrical quantity information through the signal transceiver module 14. It receives the characteristic power line carrier sensing signal reflected back by the power line through the signal transceiver module 14, performs feature extraction and parameter analysis on the received characteristic power line carrier sensing signal, and sends the analysis results to the collaborative monitoring software function module 2.

[0076] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code. The solutions in the embodiments of this application can be implemented in various computer languages, such as the object-oriented programming language Java and the interpreted scripting language JavaScript.

[0077] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0078] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0079] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0080] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.

[0081] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A method for low-voltage coordinated state sensing in a distribution network, characterized in that, The method, applied to medium- and low-voltage collaborative sensing terminals, includes: Within each analysis cycle, electrical quantity information of the medium-voltage side and low-voltage side of the distribution network within a preset frequency range is acquired in real time. Determine whether the harmonic quantity fluctuates between adjacent analysis cycles. When the harmonic quantity fluctuates in the current analysis cycle, determine that the electrical quantity information of the medium-voltage side and / or low-voltage side of the distribution network is abnormal. A characteristic power line carrier sensing signal is sent to the medium-voltage side and / or low-voltage side where electrical quantity information is abnormal, and the characteristic power line carrier sensing signal is coupled to the power line; When a characteristic power line carrier sensing signal reflected back from a power line is received, feature extraction and parameter analysis are performed on the transmitted and received characteristic power line carrier sensing signals, and the analysis results are sent to the collaborative monitoring software functional module.

2. The low-voltage coordinated state sensing method in a distribution network according to claim 1, characterized in that, Also includes: The signal features obtained by extracting features from the transmitted power line carrier sensing signals are sent to the collaborative monitoring software functional module.

3. The low-voltage coordinated state sensing method in a distribution network according to claim 1, characterized in that, The electrical quantity information includes: three-phase voltage and three-phase current.

4. The low-voltage coordinated state sensing method in a distribution network according to claim 3, characterized in that, The process of determining whether the harmonic quantities of adjacent analysis periods fluctuate includes: For each analysis cycle, a spectrum analysis is performed on the three-phase voltage and three-phase current to obtain the harmonic voltage and harmonic current; For each analysis cycle, based on the harmonic voltage, the energy and content of the even-order harmonic voltage of a specific number are calculated, and based on the harmonic current, the energy and content of the even-order harmonic current of a specific number are calculated. The energy and content of the even-order harmonic voltage of a specific number in the current analysis period are subtracted from the energy and content of the even-order harmonic voltage of a specific number in the previous analysis period to obtain the voltage energy difference and voltage content difference; the energy and content of the even-order harmonic current of a specific number in the current analysis period are subtracted from the energy and content of the even-order harmonic current of a specific number in the previous analysis period to obtain the current energy difference and current content difference. Determine whether the absolute values ​​of voltage energy difference and voltage content difference, and the absolute values ​​of current energy difference and current content difference correspond to preset thresholds. When at least one absolute value exceeds the corresponding preset threshold, it is determined that the harmonic quantity of the current analysis period is fluctuating.

5. The low-voltage coordinated status sensing method in a distribution network according to claim 1, characterized in that, Also includes: When a characteristic power line carrier sensing signal is received from a medium- or low-voltage collaborative sensing terminal that performs the corresponding transmission function, the signal characteristics of the characteristic power line carrier sensing signal are fed back to the collaborative monitoring software function module.

6. A method for low-voltage coordinated state sensing in a distribution network, characterized in that, Applied to the functional module of collaborative monitoring software, the low-voltage collaborative state sensing method for distribution networks according to any one of claims 1-5, the method includes: The analysis results sent by the medium and low voltage collaborative sensing terminal are compared with the preset signal features in the equipment status feature database; When the analysis results are abnormal, the medium- and low-voltage collaborative sensing terminal is located based on its address. The analysis results include the time delay, energy attenuation, and phase delay between the transmitted and received characteristic power line carrier sensing signals, or the signal characteristics of the transmitted and received characteristic power line carrier sensing signals.

7. The low-voltage coordinated state sensing method in a distribution network according to claim 6, characterized in that, Also includes: The signal characteristics transmitted by the medium- and low-voltage collaborative sensing terminal performing the transmitting function and the corresponding signal characteristics transmitted by the medium- and low-voltage collaborative sensing terminal performing the receiving function are compared with the preset signal characteristics in the device status characteristic database. When signal characteristics are abnormal, the low-voltage collaborative sensing terminal is located based on the address of the low-voltage collaborative sensing terminal that transmits the abnormal signal characteristics.

8. A low-voltage coordinated state sensing system for a power distribution network, characterized in that, include: Collaborative monitoring software functional modules and medium- and low-voltage collaborative sensing terminals, among which, The medium- and low-voltage collaborative sensing terminal is connected across the medium-voltage side and the low-voltage side of the transformer in the distribution network; the medium- and low-voltage collaborative sensing terminal is used to execute the distribution network medium- and low-voltage collaborative status sensing method according to any one of claims 1-5; The collaborative monitoring software module is connected to the medium- and low-voltage collaborative sensing terminal; the collaborative monitoring software module is used to execute the medium- and low-voltage collaborative status sensing method for distribution networks as described in any one of claims 6-7.

9. The low-voltage coordinated status sensing system for distribution networks according to claim 8, characterized in that, The medium- and low-voltage collaborative sensing terminal includes: a central processing unit module, a remote communication module, a data acquisition module, and a signal transceiver module, wherein... The acquisition module is used to acquire electrical quantity information of the medium-voltage side and low-voltage side of the distribution network in real time within a preset frequency range during each analysis cycle. The central processing unit module is connected to the acquisition module and the signal transceiver module, and the central processing unit module is also connected to the collaborative monitoring software function module through the remote communication module; The central processing unit module is used to determine whether the harmonic quantity fluctuates in adjacent analysis cycles. When the harmonic quantity fluctuates in the current analysis cycle, it determines that the electrical quantity information of the medium-voltage side and / or low-voltage side of the distribution network is abnormal. The signal transceiver module sends a characteristic power line carrier sensing signal to the medium-voltage side and / or low-voltage side with abnormal electrical quantity information. The signal transceiver module receives the characteristic power line carrier sensing signal reflected back from the power line, performs feature extraction and parameter analysis on the received characteristic power line carrier sensing signal, and sends the analysis results to the collaborative monitoring software function module.

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