A low voltage distribution network fault monitoring device and method

Abstract

The present invention discloses a low-voltage distribution network fault monitoring device and method. The current acquisition module in the monitoring device includes five current transformers, which respectively collect the current of the A phase, B phase, C phase, N phase and ground line of the low-voltage distribution network. The current acquisition module is connected to the power supply; the current acquisition module is electrically connected to the matching module; the matching module converts the current signal collected by the current transformer into an analog signal; the amplifier module is electrically connected to the matching module to amplify the analog signal; the sampling module is electrically connected to the amplifier module to convert the analog signal into a digital signal; the data processing module is electrically connected to the sampling module to calculate and store the digital signal; the communication module is connected to the data processing module to upload the data to the server module; the display module is electrically connected to the data processing module to display the result of the data processing module. The present invention has the advantages of low cost, high efficiency and real-time monitoring of faults.

Description

Technical Field

[0001] The present invention relates to the field of low-voltage distribution networks, and in particular to a low-voltage distribution network fault monitoring device and method. Background Art

[0002] Low-voltage distribution network refers to a distribution network composed of low-voltage distribution lines and their ancillary electrical equipment that provides electricity to users. The function of the low-voltage distribution network is to use medium-voltage or high-voltage distribution transformers as power sources and directly distribute electricity to customers through low-voltage distribution lines. Due to the large number of line equipment, only a very small number of them are equipped with online monitoring systems. Maintenance personnel do not have a comprehensive understanding of the operation of lines and equipment, and cannot monitor faults in real time. Summary of the invention

[0003] In order to solve one or all of the above technical problems, the present invention provides a low-voltage distribution network monitoring device and method, which can monitor various faults in the low-voltage distribution network.

[0004] The present invention provides a low-voltage distribution network fault monitoring device, comprising a shell, a display module, a server module, and a power supply, a current acquisition module, a matching module, an amplifier module, a sampling module, a data processing module, and a communication module built in the shell; the current acquisition module comprises five current transformers, which respectively collect currents of phase A, phase B, phase C, phase N and a ground line of the low-voltage distribution network; the matching module comprises five matching circuits matched with the current transformers, and the current transformers are used to connect with the lines to convert current signals collected by the current transformers into analog signals; the amplifier module is electrically connected to the matching module to amplify the analog signals; the sampling module is electrically connected to the amplifier module to convert the analog signals into digital signals; the data processing module is electrically connected to the sampling module to calculate and store the digital signals; the communication module is connected to the data processing module to upload the data to the server module; the display module is electrically connected to the data processing module to display the results of the data processing module.

[0005] By adopting the above technical scheme, the current of the low-voltage distribution network is acquired through the current acquisition module, the current signal is converted into an analog signal through the matching module, and the analog signal is amplified through the amplifier module. The sampling module realizes the sampling of the analog signal and converts it into a digital signal, the data processing module is used to calculate and store the data, and the results are displayed on the display module, and the collected or calculated data is uploaded to the server through the communication module. The server module completes data reception, curve display, fault analysis, conclusion formation and alarms the fault information. The technical scheme of the present application realizes real-time monitoring of low-voltage distribution network faults by acquiring the current of the power grid, processing, analyzing and judging the current. In addition, the current acquisition module, matching module and amplifier module of the technical scheme of the present application are integrated inside the monitor, which saves space and is easy to carry.

[0006] Preferably, the sampling module includes a signal processing unit and a digital-to-analog conversion unit, the processing unit is electrically connected to the digital-to-analog conversion unit; the digital-to-analog conversion unit adopts a second-order ∑-△ type digital-to-analog converter; and the signal processing unit adopts a DSP.

[0007] By adopting the above technical solution, the sampling module processes the analog signal amplified by the amplifier module, samples the analog signal through the signal processing unit, and converts the analog signal through the digital-to-analog conversion unit to obtain a digital signal.

[0008] Preferably, the communication module adopts wireless communication.

[0009] Preferably, it also includes an environmental monitoring module, which is electrically connected to the server module and is used to monitor the environmental parameters of the distribution network; it also includes an alarm module, which is electrically connected to the server module and receives the processing results of the server module and issues an alarm; the alarm module uses an audible and visual alarm.

[0010] Preferably, the environmental parameters include: ambient temperature, ambient humidity, GPS location information, battery voltage, and communication signal strength.

[0011] By adopting the above technical solution, the environmental monitoring module detects the surrounding temperature, humidity, GPS location information, battery voltage, and communication signal strength to provide a basis for fault judgment. The alarm module is electrically connected to the server module to remind the inspection personnel to perform maintenance when a fault occurs. The alarm module uses an audible and visual alarm. When a fault occurs, the audible and visual alarm is used, and the inspection personnel quickly locate and handle the fault.

[0012] The present invention also includes a low-voltage distribution network fault monitoring method, comprising the following steps: S1. collecting current information of phase A, phase B, phase C, phase N and ground wire of the low-voltage distribution network; S2. amplifying and converting the current information into analog-to-digital information to obtain digital current information; S3. performing vector superposition calculation on the digital current information; S4. uploading the data in steps S2 and S3 to a server module; S5. The server module completes data reception, analyzes the data, determines the fault type, and issues an alarm.

[0013] By adopting the above technical scheme, the current information of the low-voltage distribution network is collected, and the current information is processed, the digital current information is calculated, and the collected data is uploaded to the server side, and data reception, storage, backup and display are realized on the server side. By analyzing the data, the fault type of the low-voltage distribution network is judged and an alarm is realized, which is convenient for inspection personnel to handle the fault; the fault monitoring method of the present invention realizes the monitoring of multiple faults in the low-voltage distribution network, and the inspection personnel view the data or faults by accessing the server, which is convenient for realizing the rapid handling of faults.

[0014] Preferably, when the fault type in step S5 is a leakage fault, the judgment basis is that when the low-voltage outlet leakage current and the ground line current are greater than a first preset value, it is judged as a leakage fault.

[0015] Using the above technical solution, since the ground wire current is the neutral point grounding current of the distribution network transformer, which is less than 1 ampere under normal circumstances, the low-voltage outgoing line leakage current reflects the leakage current of the monitored low-voltage outgoing line. When the values ​​of the two are greater than the first preset value, it can be determined as a leakage fault.

[0016] Preferably, when the fault type in step S5 is a heavy load fault, the judgment basis is that the digitized current information is greater than or equal to 80% of the full load current and lasts for 5 minutes, and it is judged as a heavy load fault.

[0017] Preferably, when the fault type of step S5 is an overload fault, the judgment basis is that the digitized current information is greater than or equal to 100% of the full load current and lasts for 5 minutes, and it is determined to be an overload fault.

[0018] Preferably, when the fault type of step S5 is a three-phase unbalanced fault, the phase with the largest current and the phase with the smallest current are identified, and the judgment basis is that the digitized current information of the phase with the largest current is greater than or equal to 70% of the full load current, and the digitized current of the phase with the largest current is 1.3 times the digitized current of the phase with the smallest current, and lasts for 5 minutes, and it is judged as a three-phase unbalanced fault.

[0019] By adopting the above technical scheme, the low-voltage distribution network monitoring method of the present invention can detect leakage faults, heavy load faults, overload faults and three-phase unbalanced faults, and realize multi-fault judgment.

[0020] In summary, the low-voltage distribution network fault monitoring method and device of the present invention can realize the identification and judgment of multiple faults in the low-voltage distribution network, which is convenient for inspection personnel to inspect and repair. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a structural block diagram of one embodiment of the present invention;

[0022] Figure 2 is a flow chart of one embodiment of the present invention.

[0023] Reference numerals:

[0024] 1. Housing, 2. Power supply, 3. Display module, 4. Server module, 5. Current acquisition module, 6. Matching module, 7. Amplifier module, 8. Sampling module, 80. Signal processing unit, 81. Digital-to-analog conversion unit, 9. Data processing module, 10. Communication module, 11. Environmental monitoring module, 12. Alarm module. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0026] The monitoring devices of the existing low-voltage distribution network are often unable to predict and judge faults due to the complexity of the lines and equipment.

[0027] refer to Figure 1 The present invention proposes a low-voltage distribution network fault monitoring device, including a shell 1, a display module 3, a server module 4, and a power supply 2, a current acquisition module 5, a matching module 6, an amplifier module 7, a sampling module 8, a data processing module 9, and a communication module 10 built in the shell; the current acquisition module 5 includes five current transformers, which respectively collect currents of phase A, phase B, phase C, phase N and ground wire of the low-voltage distribution network; the current acquisition module 5 is electrically connected to the matching module 6; the matching module 6 includes five matching circuits matched with the current transformer, and the current transformer is used to connect to the line to convert the current signal collected by the current transformer into an analog signal; the amplifier module 7 is electrically connected to the matching module 7 to amplify the analog signal; the sampling module 8 is electrically connected to the amplifier module 7 to convert the analog signal into a digital signal; the data processing module 9 is electrically connected to the sampling module 8 to calculate and store the digital signal; the communication module 10 is connected to the data processing module 9 to upload the data to the server module 4; the display module 3 is electrically connected to the data processing module 9 to display the result of the data processing module 9.

[0028] By adopting the above technical solution, the current of the low-voltage distribution network is collected in real time through the current acquisition module, and the collected current is converted into an analog voltage signal through the matching module, the analog voltage signal is amplified by the amplifier module, and the signal is sampled and converted into a digital signal through the sampling module. The sampled digital signal is calculated and stored by the data processing module, and the current data is sent and presented on the display module.

[0029] In this embodiment, the power source 2 is powered by batteries, which is convenient for movement and carrying.

[0030] In this embodiment, data reception, storage, backup and display are realized in the server module 4, and the fault type of the low-voltage distribution network is judged and alarmed by analyzing the data. When making an alarm, an accident event alarm list is used to facilitate inspectors to find faults in time and handle them. Especially for low-voltage distribution networks in remote geographical locations, the sound and light alarm combined with GPS information can enable inspectors to quickly locate faults.

[0031] On the basis of the above embodiment, further, the sampling module 8 includes a signal processing unit 80 and a digital-to-analog conversion unit 81, the signal processing unit 80 is electrically connected to the digital-to-analog conversion unit 81; the digital-to-analog conversion unit 81 adopts a second-order ∑-△ type digital-to-analog converter; the signal processing unit 80 adopts a digital signal processor.

[0032] By adopting the above technical solution, the sampling module samples the amplified analog signal, the signal processing unit samples the signal, and the digital-to-analog conversion unit converts the analog signal into a digital signal.

[0033] On the basis of the above embodiment, further, the communication module 10 adopts wireless communication.

[0034] In this embodiment, the communication module 10 uses WIFI communication, Bluetooth communication, 3G / 4G / 5G communication

[0035] On the basis of the above embodiment, it further includes an environment monitoring module 11, which is electrically connected to the data processing module 9 and is used to monitor the environmental parameters of the power distribution network. It also includes an alarm module 12, which is electrically connected to the server module 4, receives the processing results of the server module 4 and issues an alarm; the alarm module 12 uses an audible and visual alarm.

[0036] On the basis of the above embodiment, further, the environmental parameters include: ambient temperature, ambient humidity, GPS location information, battery voltage, and communication signal strength.

[0037] The above technical solution is adopted, and the parameters monitored by the environmental monitoring module are used to detect the faults of the low-voltage distribution network. For example, when a heavy load or overcurrent fault occurs, the temperature will rise; GPS location information can quickly lock the fault; when the ambient humidity is high, there is often a risk of leakage. The alarm module is electrically connected to the server module to remind the inspection personnel to perform maintenance when a fault occurs. The alarm module uses an audible and visual alarm. When a fault occurs, the audible and visual alarm is used, and the inspection personnel can quickly locate and handle the fault.

[0038] refer to Figure 2 The present invention also provides a method for monitoring a low-voltage distribution network fault using a low-voltage distribution network fault monitoring device, comprising the following steps: S1. collecting current information of phase A, phase B, phase C, phase N and ground wire of the low-voltage distribution network; S2. amplifying and converting the current information into analog-to-digital information to obtain digital current information; S3. performing vector superposition calculation on the digital current information; S4. uploading the data in steps S2 and S3 to a server module; S5. The server module completes data reception, analyzes the data, determines the fault type, and issues an alarm.

[0039] By adopting the above technical solution, the current information of the low-voltage distribution network is collected, and the digital current information is obtained after processing. The information is calculated and uploaded to the server to obtain the type of distribution network fault, which is convenient for inspection personnel to carry out maintenance.

[0040] On the basis of the above embodiment, further, when the fault type in step S5 is a leakage fault, the judgment basis is that when the low-voltage outlet leakage current and the ground line current are greater than the first preset value, it is judged as a leakage fault.

[0041] With the above technical solution, since the ground current represents the grounding current of the neutral point of the distribution transformer of the low-voltage distribution network, its value is generally less than 1 ampere when no fault occurs; due to the influence of the accuracy of the current transformer, the value of the low-voltage outgoing line leakage current is generally less than 5 amperes; when a leakage fault occurs, the low-voltage outgoing line leakage current and the ground current will change due to changes in the load. When both exceed the first preset value, that is, the transformer neutral point grounding current is greater than or equal to 1 ampere and the low-voltage outgoing line leakage current is greater than or equal to 5 amperes, it can be judged as a leakage fault.

[0042] On the basis of the above embodiment, further, when the fault type in step S5 is a heavy load fault, the judgment basis is that the digitized power information is greater than or equal to 80% of the full load current and lasts for 5 minutes, and it is judged as a heavy load fault.

[0043] By adopting the above technical solution, it is possible to determine whether it is a heavy load fault based on whether the digitized power information is greater than or equal to 80% of the full load current and the duration.

[0044] In this embodiment, the full-load current is manually set according to the current carrying capacity corresponding to the material and wire diameter of the monitored low-voltage distribution network outgoing line. For example, the full-load current of a nominal cross-section of 1 square millimeter using two copper-core steel pipes is 16 amperes; the full-load current of a nominal cross-section of 1 square millimeter using two copper-core plastic pipes is 13 amperes.

[0045] In this embodiment, when the digitized current information is less than 80% of the full load current and lasts for five minutes, it is determined that the heavy load fault is resolved.

[0046] On the basis of the above embodiment, further, when the fault type of step S5 is an overload fault, the judgment basis is that the digitized current information is greater than or equal to 100% of the full load current and lasts for 5 minutes, and it is determined to be an overload fault.

[0047] By adopting the above technical solution, it is possible to determine whether it is an overload fault based on whether the digitized current information is greater than or equal to 100% of the full load current and the duration.

[0048] In this embodiment, when the digitized current information is less than 100% of the full load current and lasts for five minutes, it is determined that the overload fault is resolved.

[0049] On the basis of the above embodiment, further, when the fault type of step S5 is a three-phase unbalanced fault, the phase with the largest current and the phase with the smallest current are identified, and the judgment basis is that the digitized current information of the phase with the largest current is greater than or equal to 70% of the full load current, and the digitized current of the phase with the largest current is 1.3 times the digitized current of the phase with the smallest current, and lasts for 5 minutes, and it is judged as a three-phase unbalanced fault.

[0050] By adopting the above technical solution, by identifying the phase with the largest current and the phase with the smallest current, and judging that the phase with the largest current is greater than or equal to 70% of the full load current, and the phase with the largest current is 1.3 times the phase with the smallest current, it is judged as a three-phase unbalanced fault.

[0051] The above-described embodiments are merely descriptions of preferred implementations of the present invention, and are not intended to limit the concept and scope of the present invention. Without departing from the design concept of the present invention, various modifications and improvements made by ordinary persons in the art to the technical solution of the present invention should fall within the protection scope of the present invention, and the technical contents for which protection is sought in the present invention have been fully recorded in the claims.

Claims

1. A low voltage distribution network fault monitoring device, characterized in that: It includes a housing, a display module, a server module, an environment monitoring module, an alarm module, and a power supply, a current acquisition module, a matching module, an amplifier module, a sampling module, a data processing module, and a communication module built into the housing; The current acquisition module includes five current transformers, which respectively collect the currents of phase A, phase B, phase C, phase N and ground of the low-voltage distribution network, and the current acquisition module is electrically connected to the matching module; The matching module includes five matching circuits matched with the current transformer, the current transformer is used to connect to the line, and convert the current signal collected by the current transformer into an analog signal; The amplifier module is electrically connected to the matching module to amplify the analog signal; The sampling module is electrically connected to the amplifier module to convert the analog signal into a digital signal; The data processing module is electrically connected to the sampling module to calculate and store the digital signal; The communication module is connected to the data processing module to upload the data to the server module; The display module is electrically connected to the data processing module and displays the result of the data processing module; The sampling module includes a signal processing unit and a digital-to-analog conversion unit, wherein the processing unit is electrically connected to the digital-to-analog conversion unit; the analog conversion unit adopts a second-order ∑-△ type digital-to-analog converter; and the signal processing unit adopts a DSP; The environmental monitoring module is electrically connected to the server module and is used to monitor the environmental parameters of the power distribution network; the environmental parameters include ambient temperature, ambient humidity, and GPS location information; the alarm module is electrically connected to the server module, receives the processing results of the server module and issues an alarm; the alarm module uses an audible and visual alarm; The server module is used to analyze the data, determine the fault type, and issue an alarm prompt in the form of an accident event alarm list; when the fault type is a three-phase unbalanced fault, the phase with the largest current and the phase with the smallest current are identified, and the judgment is based on the digitized current information of the phase with the largest current being greater than or equal to 70% of the full load current, and the digitized electrical quantity of the phase with the largest current is 1.3 times the digitized current of the phase with the smallest current, and lasts for 5 minutes, and it is judged as a three-phase unbalanced fault.

2. The low voltage distribution network fault monitoring device according to claim 1, characterized in that: The communication module adopts wireless communication.

3. The low voltage distribution network fault monitoring device according to claim 1, characterized in that: The environmental parameters include: battery voltage and communication signal strength.

4. A low-voltage distribution network fault monitoring method applied to the low-voltage distribution network fault monitoring device according to any one of claims 1 to 3, characterized in that: The following steps are involved: S1. Collect current information of phase A, phase B, phase C, phase N and ground of low voltage distribution network; S2. amplifying and converting the current information into analog-to-digital information to obtain digital current information; S3. Perform vector superposition calculation on the digital current information; S4. Upload the data in steps S2 and S3 to the server module; S5. The server module completes data reception, analyzes the data, determines the fault type, and issues an alarm.

5. The low voltage distribution network fault monitoring method according to claim 4, characterized in that: When the fault type in step S5 is a leakage fault, the judgment basis is that when the low-voltage outlet leakage current and the ground line current are greater than the first preset value, it is judged as a leakage fault.

6. The low voltage distribution network fault monitoring method according to claim 4, characterized in that: When the fault type in step S5 is a heavy load fault, the judgment basis is that the digitized power information is greater than or equal to 80% of the full load current and lasts for 5 minutes, and it is judged as a heavy load fault.

7. The low voltage distribution network fault monitoring method according to claim 4, characterized in that: When the fault type of step S5 is an overload fault, the judgment basis is that the digitized power information is greater than or equal to 100% of the full load current and lasts for 5 minutes, and it is judged as an overload fault.

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