Distributed acquisition terminal device for low-voltage power distribution network

Abstract

The utility model relates to the technical field of low-voltage power distribution networks, and provides a distributed acquisition terminal device for a low-voltage power distribution network, which comprises an integrated acquisition unit, a network topology identification unit, a communication unit, a power supply unit and a data processing unit, the power supply unit is respectively connected with the network topology identification unit, the communication unit and the data processing unit; one end of the network topology identification unit and one end of the integrated acquisition unit are respectively connected with the low-voltage power distribution network, and the other end of the integrated acquisition unit and the other end of the network topology identification unit are respectively connected with the data processing unit; the data processing unit is also connected with the communication unit; the distributed acquisition terminal device can effectively identify the network topology of the power distribution network.

Description

Technical Field

[0001] This utility model relates to the technical field of low-voltage distribution networks, and more specifically, to a distributed acquisition terminal device for low-voltage distribution networks. Background Technology

[0002] A distribution network is a power grid that receives electrical energy from the transmission network or regional power plants and distributes it locally through distribution facilities or through several branch lines according to voltage to various types of users. Distribution networks are usually equipped with a master station, which is used to monitor and analyze the power quality of distribution network equipment in real time.

[0003] With the rapid development of the social economy, the electricity demand from all sectors is constantly increasing, posing a huge challenge to power grid companies. For a long time, there have been limited methods for identifying fault types in distribution rooms and low-voltage transformer areas. When a fault occurs, it is usually simply handled by tripping, followed by on-site investigation by maintenance technicians. At the same time, due to the unclear connection relationship between the "customer-line-transformer," especially in older transformer areas, some topologies cannot be directly obtained, requiring manual investigation, which is a huge workload and a waste of human and material resources. The "transformer" in "customer-line-transformer" refers to the transformer in the transformer area, which converts high-voltage electrical energy into low-voltage electrical energy suitable for users. Each transformer area has one or more transformers responsible for supplying power to the users in that area; "line" refers to the distribution line; and "customer" refers to the user consuming electricity.

[0004] Furthermore, the lack of real-time data on low-voltage lines results in a lack of voltage quality monitoring in low-voltage distribution areas, making it impossible to analyze the causes and provide early warnings for problems such as three-phase imbalance and low voltage. The power distribution room lacks advanced monitoring and early warning functions for low-voltage distribution area phase loss and grounding faults, making it impossible to achieve real-time monitoring and trend early warning of power outages caused by low-voltage distribution area faults.

[0005] In summary, existing technologies lack effective means to monitor faults on low-voltage distribution lines, making it impossible to identify fault types such as grounding faults and phase loss faults. The "household-line-transformer" connection relationship (network topology of the low-voltage distribution network) in low-voltage distribution areas is unclear, requiring extensive manual investigation. Furthermore, faults on lines cannot be located. When faults occur on complex transmission lines in urban villages, maintenance personnel find it difficult to reach the correct fault location in a short time. There is also a lack of effective means to monitor the voltage quality of low-voltage distribution lines, making it impossible to identify frequent power outages, low voltage, and their causes. Utility Model Content

[0006] To overcome the shortcomings of the prior art, which is unable to effectively identify the topology of the distribution network, thus failing to identify and locate faults, this utility model provides a distributed acquisition terminal device for low-voltage distribution networks that can effectively identify the topology of the distribution network.

[0007] To solve the above-mentioned technical problems, the technical solution of this utility model is as follows:

[0008] A distributed data acquisition terminal device for low-voltage distribution networks includes: an integrated data acquisition unit, a network topology identification unit, a communication unit, a power supply unit, and a data processing unit.

[0009] The power supply unit is connected to the network topology identification unit, the communication unit, and the data processing unit, respectively.

[0010] One end of the network topology identification unit and one end of the integrated acquisition unit are respectively connected to the low-voltage distribution network, and the other end of the integrated acquisition unit and the other end of the network topology identification unit are respectively connected to the data processing unit;

[0011] The data processing unit is also connected to the communication unit.

[0012] Compared with the prior art, the beneficial effects of this utility model's technical solution are:

[0013] This application acquires real-time data of low-voltage distribution network branch lines through an integrated acquisition unit, processes the acquired data through a data processing unit, and the data processing unit receives external signals through a communication unit. Based on the received signals and actual needs, the data is distributed to a network topology identification unit, which then identifies the network topology of the low-voltage distribution network. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the first structure of the distributed data acquisition terminal device for low-voltage power distribution networks proposed in Example 1;

[0015] Figure 2 This is a schematic diagram of the second structure of the distributed acquisition terminal device for low-voltage power distribution networks proposed in Example 3;

[0016] Figure 3 The circuit diagram of the 485 circuit proposed in Example 3 is shown below;

[0017] Figure 4 This is a schematic diagram of the phase-to-phase short-circuit current and voltage changes proposed in Example 3. Detailed Implementation

[0018] The accompanying drawings are for illustrative purposes only and should not be construed as limiting the scope of this patent.

[0019] To better illustrate this embodiment, some parts in the accompanying drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions;

[0020] It will be understood by those skilled in the art that certain well-known structures and their descriptions may be omitted in the accompanying drawings.

[0021] The technical solution of this utility model will be further described below with reference to the accompanying drawings and embodiments.

[0022] Example 1

[0023] This embodiment proposes a distributed data acquisition terminal device for low-voltage power distribution networks. Figure 1 This is a schematic diagram of the first structure of the distributed acquisition terminal device for low-voltage power distribution network proposed in this embodiment; Figure 1 In this context, A, B, C, and N represent the A-phase line, B-phase line, C-phase line, and neutral line of a low-voltage distribution network, respectively. Figure 1 The port used to receive external signals is not shown.

[0024] This embodiment proposes a distributed data acquisition terminal device for low-voltage distribution networks, including: an integrated data acquisition unit, a network topology identification unit, a communication unit, a power supply unit, and a data processing unit;

[0025] The power supply unit is connected to the network topology identification unit, the communication unit, and the data processing unit, respectively.

[0026] One end of the network topology identification unit and one end of the integrated acquisition unit are respectively connected to the low-voltage distribution network, and the other end of the integrated acquisition unit and the other end of the network topology identification unit are respectively connected to the data processing unit;

[0027] The data processing unit is also connected to the communication unit.

[0028] As an example, the low-voltage distribution network has a main station and several branch lines. Each branch line is equipped with the distributed acquisition terminal device. The A-phase line, B-phase line, C-phase line and neutral line of the branch line are respectively connected to one end of the network topology identification unit and one end of the integrated acquisition unit. The other end of the integrated acquisition unit and the other end of the network topology identification unit are respectively connected to the data processing unit.

[0029] As an example, the distributed acquisition terminal device on each branch line receives signals from outside the distributed acquisition terminal device where the communication unit is located through the communication unit.

[0030] In this embodiment, the application collects real-time data of low-voltage distribution network branch lines through an integrated acquisition unit, processes the collected data through a data processing unit, and the data processing unit receives external signals through a communication unit. Based on the received signals and actual needs, the data is distributed to a network topology identification unit, which then identifies the network topology of the low-voltage distribution network.

[0031] In one optional embodiment, the integrated acquisition unit includes several voltage sensors, several current sensors, a voltage acquisition circuit, a current acquisition circuit, and a three-phase power metering module;

[0032] One end of the voltage sensor is connected to the input terminal of the voltage acquisition circuit, and the other end of the voltage sensor is connected to the low-voltage distribution network.

[0033] One end of the current sensor is connected to the input terminal of the current acquisition circuit, and the other end of the current sensor is connected to the low-voltage distribution network.

[0034] The output terminals of the voltage acquisition circuit and the current acquisition circuit are respectively connected to the input terminal of the three-phase power metering module, and the output terminal of the three-phase power metering module is connected to the data processing unit.

[0035] As an example, the integrated acquisition unit includes first, second, third, and fourth voltage sensors, first, second, third, and fourth current sensors, a voltage acquisition circuit, a current acquisition circuit, and a three-phase energy metering module. One end of each of the first, second, third, and fourth voltage sensors is connected to the input terminal of the voltage acquisition circuit, and one end of each of the first, second, third, and fourth current sensors is connected to the input terminal of the current acquisition circuit. The other ends of the first voltage sensor and the first current sensor are connected to the A-phase line, the other ends of the second voltage sensor and the second current sensor are connected to the B-phase line, the other ends of the third voltage sensor and the third current sensor are connected to the C-phase line, and the other ends of the fourth voltage sensor and the fourth current sensor are connected to the neutral line. The output terminals of the voltage acquisition circuit and the current acquisition circuit are connected to the input terminal of the three-phase energy metering module, and the output terminal of the three-phase energy metering module is connected to the data processing unit.

[0036] As an example, existing data acquisition and measurement units are distributed and installed indoors or in enclosed rooms such as power distribution rooms and substations, lacking an integrated industrial data acquisition and measurement unit on outdoor lines. This optional embodiment makes up for this deficiency.

[0037] In an optional embodiment, the network topology identification unit is configured with a characteristic current transmitting circuit and a characteristic current identification circuit. The first terminals of the characteristic current transmitting circuit and the characteristic current identification circuit are respectively connected to the data processing unit, the second terminals are respectively connected to the low-voltage distribution network, and the third terminals are respectively connected to the power supply unit.

[0038] As an example, the second terminals of the characteristic current transmitting circuit and the characteristic current identifying circuit are respectively connected to the A-phase line, B-phase line, C-phase line and neutral line of the branch line.

[0039] In one optional embodiment, the power supply unit includes a power supply circuit and a capacitor backup power supply, both of which are connected to the network topology identification unit, the communication unit, and the data processing unit, respectively.

[0040] In an optional embodiment, a fault identification and detection unit is further included, which includes a phase-to-phase short-circuit fault monitoring module, a current imbalance monitoring module, and a ground fault monitoring module.

[0041] One end of each of the phase-to-phase short-circuit fault monitoring module, current imbalance monitoring module, and ground fault monitoring module is connected to the data processing unit, and the other end is connected to the power supply unit.

[0042] Example 2

[0043] This embodiment is an improvement upon the distributed acquisition terminal device for low-voltage power distribution networks proposed in Embodiment 1.

[0044] This embodiment proposes a distributed data acquisition terminal device for low-voltage distribution networks, including: an integrated data acquisition unit, a network topology identification unit, a communication unit, a power supply unit, and a data processing unit;

[0045] The power supply unit is connected to the network topology identification unit, the communication unit, and the data processing unit, respectively.

[0046] One end of the network topology identification unit and one end of the integrated acquisition unit are respectively connected to the low-voltage distribution network, and the other end of the integrated acquisition unit and the other end of the network topology identification unit are respectively connected to the data processing unit;

[0047] The data processing unit is also connected to the communication unit.

[0048] As an example, the low-voltage distribution network has a main station and several branch lines. Each branch line is equipped with the distributed acquisition terminal device. The A-phase line, B-phase line, C-phase line and neutral line of the branch line are respectively connected to one end of the network topology identification unit and one end of the integrated acquisition unit. The other end of the integrated acquisition unit and the other end of the network topology identification unit are respectively connected to the data processing unit.

[0049] As an example, the distributed acquisition terminal device on each branch line receives signals from outside the distributed acquisition terminal device where the communication unit is located through the communication unit.

[0050] In this embodiment, the application collects real-time data of low-voltage distribution network branch lines through an integrated acquisition unit, processes the collected data through a data processing unit, and the data processing unit receives external signals through a communication unit. Based on the received signals and actual needs, the data is distributed to a network topology identification unit, which then identifies the network topology of the low-voltage distribution network.

[0051] In one optional embodiment, the communication unit includes a three-phase carrier module, the first end of which is connected to the data processing unit, the second end of which receives signals from outside the distributed acquisition terminal device, and the third end of which is connected to the power supply unit.

[0052] As an example, the second end of the three-phase carrier module is connected to distributed acquisition terminal devices on other branch lines and the main station of the low-voltage distribution network, wherein the other branch lines are branch lines other than the branch line where the three-phase carrier module is located.

[0053] In an optional embodiment, the communication unit further includes a 485 circuit, the first end of which is connected to the data processing unit, the second end of which receives signals from outside the distributed acquisition terminal device, and the third end of which is connected to the power supply unit.

[0054] As an example, the 485 circuit is generally used for calibration of the three-phase energy metering module, temporary on-site meter reading, etc. When calibrating the data output by the three-phase energy metering module, the data processing unit communicates with the three-phase energy metering module. After processing the data, the data processing unit delivers it through the 485 circuit and an external interrupt. The second end of the 485 circuit is an external data interface, through which signals from external devices can be received from the distributed acquisition terminal device where the 485 circuit is located.

[0055] In an optional embodiment, the communication unit further includes a WIFI module, the first end of which is connected to the data processing unit, the second end of which receives signals from outside the distributed acquisition terminal device, and the third end of which is connected to the power supply unit.

[0056] In one optional embodiment, the integrated acquisition unit is connected to the low-voltage distribution network via a puncture connection.

[0057] In an optional embodiment, the distributed acquisition terminal device further includes a housing, and the integrated acquisition unit, network topology identification unit, communication unit, power supply unit, and data processing unit are all disposed inside the housing. The outer surface of the housing is provided with a buckle, and the distributed acquisition terminal device is fastened to the line of the low-voltage power distribution network through the buckle.

[0058] As an example, when the distributed acquisition terminal device further includes a fault identification and detection unit, the fault identification and detection unit is also located inside the housing.

[0059] Example 3

[0060] This embodiment proposes a specific implementation example based on the distributed acquisition terminal device for low-voltage distribution networks proposed in Embodiments 1 and 2.

[0061] Figure 2 This is a schematic diagram of the second structure of the distributed data acquisition terminal device for low-voltage distribution networks proposed in this embodiment, as shown below. Figure 2 As shown, in this embodiment, the distributed acquisition terminal device is made into an integrated, movable, and detachable device. The integrated, movable, and detachable device includes: a main control board, a power supply board, and an integrated current transformer. The various boards are electrically connected by plugging and unplugging industrial-grade connectors, which is very convenient for maintenance and debugging. It also has an integrated, movable, and detachable outdoor industrial-grade shell design, which greatly improves operation and maintenance efficiency and reduces operation and maintenance costs.

[0062] The main control board uses an industrial-grade chip as its microprocessor, boasting extremely high performance and reliability. Specifically, the main control board integrates a microprocessor, memory, a hardware watchdog chip, various peripheral interfaces, an RTC and clock battery, WIFI, a 1-channel 485 circuit, and an HPLC (three-phase carrier) module. The main control board enables communication through the WIFI module, the 1-channel 485 circuit, and the HPLC (three-phase carrier) module. Through various peripheral interfaces, it allows the terminal device to receive signals from outside the distributed acquisition terminal device. Furthermore, the main control board, through the combination of the microprocessor, memory, hardware watchdog chip, RTC, and clock battery, enables data processing by the data processing unit, performs logical operations by the network topology identification unit and the fault identification and detection unit, and can send and receive commands through the communication unit, executing corresponding logical operations based on the commands. These logical operations include, but are not limited to, the logical operations of the network topology identification unit and the fault identification and detection unit.

[0063] As an example, the microprocessor is the STM32L151RDT6 from the STM32 series; the memory uses FLASH W25Q16JVSSIQ and ferroelectric FM24CL64-G; the peripheral interfaces include serial port, IIC, SDIO, SPI, etc.; the RTC and clock battery use PCF8563T to provide time information for the terminal; the WIFI uses ESP-12F to facilitate data acquisition and upgrades by on-site maintenance personnel. Figure 3 This is the circuit diagram of the 485 circuit proposed in this embodiment. Figure 3 This illustration demonstrates the specific components and their connections in a 485 circuit that uses a MAX485 transceiver and a high-speed optocoupler chip for isolation, and a TVS diode for protection. As an example, the MAX485 transceiver can be replaced by an SP485 transceiver.

[0064] The power board includes an industrial-grade power module (corresponding to the power circuit and the input power of the power circuit), a supercapacitor backup circuit (corresponding to the capacitor backup circuit), a characteristic current circuit (corresponding to the characteristic current transmitting circuit and the characteristic current identification circuit), and an electrical quantity acquisition circuit (corresponding to the voltage acquisition circuit, the current acquisition circuit, and the three-phase power metering module).

[0065] As an example, the power supply circuit has a single-phase input of 170-500ACV and a single-phase output of 12VDC, which is an industrial-grade power supply. The power supply circuit uses a TPS54202 to generate the required 3.3V and 5V power supplies, and uses a DC-DC module for external isolation. The capacitor backup circuit is equipped with a 1F / 13.5V module and a charge / discharge management circuit. The capacitor backup circuit charges when the terminal device is powered on, and can maintain terminal operation for more than 8 minutes when the external power to the terminal device fails. The characteristic current circuit is based on hardware topology recognition technology, which sends a current of a characteristic frequency downstream of the power distribution line and detects the amplitude of the current of the characteristic frequency upstream. The electrical quantity acquisition circuit uses the HT7132 metering system (corresponding to the three-phase power metering module) to achieve real-time acquisition and correction of low-voltage line panoramic electrical quantities, and simultaneously reports data in seconds.

[0066] The integrated instrument transformer integrates four current sensors (A, B, and C phases, and the neutral line) with 0.5% accuracy and four voltage sensors with 0.5% accuracy. It features automatic, fully digital output and all-weather outdoor operation. The integrated instrument transformer adopts an industrial-grade, fully enclosed design, integrating current and voltage acquisition to achieve fully digital output of electrical quantities. Its fully isolated circuit design, combined with industrial-grade puncture-line connection technology, ensures efficient, reliable, stable, and convenient outdoor use. The acquisition unit utilizes digital isolation chips, optocoupler technology, and epoxy resin potting process to integrate current acquisition, voltage acquisition, and line puncture contact into a single unit. Through its industrial-grade housing design, it fills the gap in integrated outdoor instrument transformer acquisition equipment for low-voltage lines.

[0067] In this embodiment, the distributed data acquisition terminal is installed on low-voltage lines (including outdoor overhead lines and indoor lines). The installation adopts a snap-fit ​​structure, which does not damage the original equipment structure and insulation performance. The internal circuit design of the distributed data acquisition terminal adopts a modular design, highly integrating a high-speed data acquisition module, an intelligent microprocessor module, a communication module adapted for mobile Internet, a network topology identification module, a power supply module, an integrated current transformer module, and functional auxiliary modules.

[0068] The distributed data acquisition terminal uses an integrated current transformer to clip onto low-voltage lines for power extraction, eliminating the need for additional wiring and power supply. Once powered on, the terminal can collect line data and monitor load characteristics. Simultaneously, in the event of a power outage, it can be powered by a supercapacitor backup power source, which also saves data and generates alarms. Currently, the power grid lacks monitoring equipment on low-voltage lines; monitoring is almost exclusively done at nodes such as incoming and outgoing lines, switch rooms, and transformers. The data acquisition terminal, suspended above low-voltage lines, directly acquires real-time line information, effectively filling the data gap in low-voltage lines. The most prominent functional feature of this terminal is its ability to identify and diagnose low-voltage line faults and generate network topology.

[0069] The functional logic of the distributed data acquisition terminal device is as follows:

[0070] The integrated current transformer module (corresponding to the integrated acquisition unit) outputs a high-precision digital signal to a high-performance, low-power STM32 processor for real-time processing, thereby obtaining a large amount of real-time data from the low-voltage line.

[0071] The communication unit integrates HPLC and WIFI dual-mode communication, enabling network communication within the distribution area and microsecond-level synchronous sampling of the distribution area clock. The distributed acquisition terminal communicates with the front-end sensing terminal or the master station via HPLC to upload data and fault information, receive various commands, transmit and receive characteristic currents, and support network topology generation.

[0072] Maintenance personnel can use Wi-Fi to acquire on-site data, issue work commands, and adjust parameter settings.

[0073] When the network topology identification unit receives a characteristic current injection command, it sends a current of a characteristic frequency to the downstream nodes of the branch line through the characteristic current transmitting circuit. Upon receiving a characteristic current identification command, it detects the amplitude of the characteristic frequency current upstream of the branch line. This characteristic current is encoded using OOK modulation at the injection end and decoded using FFT analysis at the receiving end to determine the nodes through which this characteristic current flows at the same time. This allows for rapid identification of the hierarchical and sequential relationships of circuit branches, thereby achieving network topology identification. Specifically, the characteristic current transmitting circuit controls a field-effect transistor load to perform constant current load modulation, superimposing a characteristic current with a frequency of 833.3Hz onto the power frequency current. The characteristic current is modulated using on / off switches to achieve "1" and "0" modulation, transmitting the necessary information to the characteristic current identification circuit of the identification unit. When identifying the characteristic current signal, the characteristic current identification circuit acquires the original waveform of the current signal on the line at a sampling rate of 6.4kHz. The original waveform is expanded using Discrete Fourier Transform (DFT) to calculate the amplitude of each harmonic frequency domain and identify whether the peak value is valid in a specific harmonic frequency domain.

[0074] The functional logic of the fault intelligent identification and detection module is mainly as follows:

[0075] Phase-to-phase short circuit fault monitoring:

[0076] The distributed acquisition terminal detects the normal current and voltage of the line. After detecting the change in phase-to-phase short-circuit fault current, it reports the fault information to the front-end sensing terminal or the main station. The phase-to-phase short-circuit fault characteristics are as follows: the normal load current is I1. The phase-to-phase short-circuit fault causes the current to suddenly increase from I1 to I2. After time t, the circuit breaker trips, causing the current to drop to 0A. The phase voltage U1 is the voltage under normal line operation. After the circuit breaker trips, the voltage drops suddenly from U1 to 0V. Figure 4This is a schematic diagram of the phase-to-phase short-circuit current and voltage changes proposed in this embodiment. Figure 4 The process of current and voltage changes during a phase-to-phase short-circuit fault is shown.

[0077] Current imbalance monitoring:

[0078] Current imbalance refers to the inconsistent amplitudes of the three-phase currents in a power system, with the amplitude difference exceeding the specified range. This is caused by an imbalance in the load applied to each phase power source and is a fundamental load configuration issue. The occurrence of three-phase imbalance is related to user load characteristics, as well as power system planning and load allocation. Distributed acquisition terminals collect the currents of the three-phase branches and report the current imbalance alarms of the branches to the front-end sensing terminals or branch master stations via communication units.

[0079] Three-phase current imbalance = (MAX phase current) (Three-phase average current) / (Three-phase average current × 100%)

[0080] (1) Alarm occurs

[0081] If the current imbalance rate exceeds the upper limit threshold (default 50%) and persists for a certain period of time (default 15 minutes), a current imbalance alarm will be generated.

[0082] (2) Alarm recovery

[0083] If a current imbalance alarm occurs and the current imbalance rate is less than the lower limit threshold (40% for three-phase four-wire by default) for a certain period of time (15 minutes by default), a current imbalance recovery alarm will be generated.

[0084] Ground fault monitoring:

[0085] The ground fault monitoring and alarm function mainly uses distributed acquisition terminals to collect the residual current and phase voltage of the low-voltage outgoing line of the transformer for judgment and location.

[0086] The specific procedure for residual current detection involves installing a current transformer (CT) on each of the three-phase low-voltage outgoing lines and the neutral line (N). The vector sum of the currents in the three phases and the neutral line (N) is obtained: IA + IB + IC + IN. When the line is normal, this vector sum is zero. When a phase-to-ground fault occurs, the fault current will flow through the protective ground wire, meaning IA + IB + IC + IN ≠ 0. In this case, the value is the ground fault current plus the normal leakage current, which is the residual current. Therefore, when the detected residual current exceeds the alarm threshold (configurable) and the duration exceeds the time threshold (configurable), a ground fault can be identified.

[0087] When a line experiences a ground fault, the voltage drops rapidly to 0. The specific phase line where the ground fault occurred can be located based on the phase voltage collected by the distributed acquisition terminal.

[0088] Ground fault detection: During monitoring, the front-end sensing terminal obtains the current on lines ABCN through current measurement and calculates the vector sum of the four currents. When the amplitude of this vector sum exceeds a set threshold and the duration exceeds a set time, a ground fault is detected.

[0089] Fault location: When a ground fault is detected by the front-end sensing terminal of a certain section, and a ground fault also occurs in the upstream line of that section, while the downstream line is not faulty, it is determined that the fault occurred in that section.

[0090] This distributed data acquisition terminal has characteristic current transmission and identification functions. Through HPLC communication, it coordinates the operation of the injection and identification modules throughout the entire distribution area, collects the dependency relationships of each module, and stitches them together to form a complete topology map. Based on the topology map, the complete "household-line-transformer" relationship network can clearly reflect the load characteristics, voltage quality, fault type, and location of each line at its specific location, greatly facilitating maintenance and repair by operation and maintenance personnel and analysis and early warning by system personnel.

[0091] The low-voltage line electrical quantity front-end acquisition function adopts an integrated acquisition unit, which has advantages over the existing discrete PT (voltage transformer) and CT (current transformer) on the market. It can avoid the problem that large discrete sensors cannot be installed at the same point at the same time, and also solves the problem that acquisition units cannot be installed on outdoor low-voltage lines.

[0092] This distributed data acquisition terminal has the capability to acquire 4 channels of current and 4 channels of voltage signals, with a linearity error of less than 0.5%, active power up to 0.2 seconds and reactive power up to 0.5 seconds. It provides 41st harmonic analysis, supports IEC61000-4-30 power quality analysis, and provides electrical parameters such as power factor, phase angle, line frequency, and voltage angle. The main processor's high-performance computing capabilities provide voltage quality analysis and load characteristic analysis of the line, perform fault analysis and early warning for phase loss, grounding, and three-phase imbalance, and accurately identify the fault point.

[0093] The same or similar labels correspond to the same or similar parts;

[0094] The terms used to describe positional relationships in the accompanying drawings are for illustrative purposes only and should not be construed as limiting this patent.

[0095] Obviously, the above embodiments of this utility model are merely examples for clearly illustrating this utility model, and are not intended to limit the implementation of this utility model. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the protection scope of the claims of this utility model.

Claims

1. A distributed data acquisition terminal device for low-voltage distribution networks, characterized in that, include: The system includes an integrated acquisition unit, a network topology identification unit, a communication unit, a power supply unit, and a data processing unit. The power supply unit is connected to the network topology identification unit, the communication unit, and the data processing unit, respectively. One end of the network topology identification unit and one end of the integrated acquisition unit are respectively connected to the low-voltage distribution network, and the other end of the integrated acquisition unit and the other end of the network topology identification unit are respectively connected to the data processing unit; The data processing unit is also connected to the communication unit.

2. The distributed data acquisition terminal device for low-voltage distribution networks according to claim 1, characterized in that, The integrated acquisition unit includes several voltage sensors, several current sensors, a voltage acquisition circuit, a current acquisition circuit, and a three-phase power metering module. One end of the voltage sensor is connected to the input terminal of the voltage acquisition circuit, and the other end of the voltage sensor is connected to the low-voltage distribution network. One end of the current sensor is connected to the input terminal of the current acquisition circuit, and the other end of the current sensor is connected to the low-voltage distribution network. The output terminals of the voltage acquisition circuit and the current acquisition circuit are respectively connected to the input terminal of the three-phase power metering module, and the output terminal of the three-phase power metering module is connected to the data processing unit.

3. The distributed data acquisition terminal device for low-voltage distribution networks according to claim 1, characterized in that, The network topology identification unit is equipped with a characteristic current transmitting circuit and a characteristic current identification circuit. The first terminals of the characteristic current transmitting circuit and the characteristic current identification circuit are respectively connected to the data processing unit, the second terminals are respectively connected to the low-voltage distribution network, and the third terminals are respectively connected to the power supply unit.

4. The distributed data acquisition terminal device for low-voltage distribution networks according to claim 1, characterized in that, The power supply unit includes a power supply circuit and a capacitor backup power supply. The power supply circuit and the capacitor backup power supply are respectively connected to the network topology identification unit, the communication unit, and the data processing unit.

5. The distributed data acquisition terminal device for low-voltage distribution networks according to claim 1, characterized in that, It also includes a fault identification and detection unit, which includes a phase-to-phase short-circuit fault monitoring module, a current imbalance monitoring module, and a ground fault monitoring module; One end of each of the phase-to-phase short-circuit fault monitoring module, current imbalance monitoring module, and ground fault monitoring module is connected to the data processing unit, and the other end is connected to the power supply unit.

6. The distributed data acquisition terminal device for low-voltage distribution networks according to claim 1, characterized in that, The communication unit includes a three-phase carrier module. The first end of the three-phase carrier module is connected to the data processing unit, the second end receives signals from outside the distributed acquisition terminal device, and the third end is connected to the power supply unit.

7. The distributed data acquisition terminal device for low-voltage distribution networks according to claim 6, characterized in that, The communication unit also includes a 485 circuit, the first end of which is connected to the data processing unit, the second end of which receives signals from outside the distributed acquisition terminal device, and the third end of which is connected to the power supply unit.

8. The distributed data acquisition terminal device for low-voltage distribution networks according to claim 7, characterized in that, The communication unit also includes a WIFI module. The first end of the WIFI module is connected to the data processing unit, the second end receives signals from outside the distributed acquisition terminal device, and the third end is connected to the power supply unit.

9. The distributed data acquisition terminal device for low-voltage distribution networks according to claim 1, characterized in that, The integrated acquisition unit is connected to the low-voltage power distribution network via a puncture connection.

10. The distributed data acquisition terminal device for low-voltage distribution networks according to any one of claims 1 to 9, characterized in that, The distributed acquisition terminal device also includes a housing, and the integrated acquisition unit, network topology identification unit, communication unit, power supply unit, and data processing unit are all disposed inside the housing. The outer surface of the housing is provided with a buckle, and the distributed acquisition terminal device is connected to the line of the low-voltage distribution network through the buckle.

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