Power line external damage prevention alarm device

Abstract

The application discloses an external damage alarm device for a power line, which comprises at least three voltage transformers connected in a star mode, a high-voltage side of each voltage transformer is connected with a three-phase live wire and a zero line in front of a power distribution line respectively, and a ground wire of the voltage transformer side is connected with the ground through an always-open switch; the device further comprises a rectifier circuit, a single-chip microcomputer, a control circuit and an internet of things module; the single-chip microcomputer receives a rectified direct-current voltage output by each voltage transformer, comprehensively judges whether a power line in the power distribution network has a fault and a corresponding fault type according to the direct-current voltages, and then timely reports the fault through the internet of things module; and the device has the characteristics of simple structure, small size, low cost and good safety.

Description

Technical Field

[0001] This invention relates to the field of low-voltage power distribution line technology in power transmission and distribution lines, and particularly to a power line anti-external damage alarm device. Background Technology

[0002] With the urbanization of Shenzhen, many urban renewal projects have commenced in recent years, leading to a growing problem of power line theft. The relocation of residents in these urban renewal areas leaves houses unoccupied and power unused, making it difficult to detect theft of low-voltage overhead lines immediately. This frequent theft not only causes asset losses for companies but also poses safety hazards, seriously endangering the personal safety and property of the people. Thieves often choose to commit their crimes at night, and the urban area has many blind spots in surveillance. Therefore, theft of overhead lines is characterized by its simplicity, difficulty in detection, tracking, and control, as well as its randomness and suddenness, resulting in significant economic losses to the power grid. Furthermore, the exposed cut lines pose a risk of electric shock, causing adverse social impacts.

[0003] Existing line damage prevention and detection solutions are mainly visual inspection solutions. For example, video surveillance cameras are installed on power line towers, and image recognition technology in the field of artificial intelligence is used to identify potential faults in the line channel. Information is then obtained through wireless 3G / 4G communication, and finally, the early warning information of line faults is uploaded to the mobile app of the inspection personnel through push technology.

[0004] However, the existing solutions have many shortcomings in addressing the problem of wire theft during urban renewal: for example, the investment in hardware facilities is large, the data traffic cost of monitoring equipment is high; the manpower, material resources and costs required for equipment maintenance are high; the imaging results of the equipment are greatly affected by weather factors, and the results are poor in bad weather; and because there is still much room for improvement in AI algorithms, there is currently a high false alarm rate. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a power line anti-external damage alarm device, which has the characteristics of simple structure, small size, low cost and good safety.

[0006] In one aspect, the present invention provides a power line damage prevention alarm device, which includes at least:

[0007] Three voltage transformers are connected in a star configuration. The high-voltage side of each voltage transformer is connected to one of the three-phase live wires and the neutral wire in front of the distribution line meter. The ground wire on the voltage transformer side is grounded through a normally open switch.

[0008] The rectifier circuit is connected to the low-voltage side of the three voltage transformers respectively, and is used to rectify the low-voltage signal output by each voltage transformer to form a DC voltage.

[0009] The microcontroller receives the rectified DC voltage output from each voltage transformer and comprehensively judges whether the power lines in the power distribution network are faulty and the corresponding fault type based on the DC voltage.

[0010] The control circuit is connected between the microcontroller and the normally open switch and each voltage transformer. It is used to control the opening and closing of the normally open switch according to the command of the microcontroller, and to control the opening and closing between the high voltage side of the voltage transformer and the three-phase live wire.

[0011] The Internet of Things (IoT) module is connected to the microcontroller and is used to send out the power line faults and corresponding fault types detected by the microcontroller.

[0012] Preferably, the fault types include: single-phase open circuit fault, two-phase open circuit fault, three-phase open circuit fault, neutral wire open circuit fault, neutral wire open circuit + single-phase open circuit fault, neutral wire open circuit + two-phase open circuit fault, and three-phase open circuit fault.

[0013] Preferably, the microcontroller further determines whether the power line is faulty and the corresponding fault type using the following method:

[0014] When the normally open switch is in the open state, if the high voltage terminal voltage of all three voltage transformers is detected to be zero, the control will close the normally open switch. If the high voltage terminal voltage of all three voltage transformers remains zero at this time, the current fault type is determined to be a three-phase open circuit fault; if the high voltage terminal voltage of one voltage transformer is 220V at this time, the current fault type is determined to be a neutral wire open circuit + two-phase open circuit fault.

[0015] When the normally open switch is in the open state, if the high voltage terminal voltage of both voltage transformers is zero and the high voltage terminal voltage of the other voltage transformer is 220V, the fault type at this time is determined to be a two-phase open circuit fault.

[0016] When the normally open switch is in the open state, if it is determined that the high voltage terminal voltage of one voltage transformer is zero, and the high voltage terminal voltage of the other two voltage transformers is 220V, the fault type at this time is determined to be a single-phase open circuit fault.

[0017] When the normally open switch is in the open state, when it is determined that the high voltage terminal voltage of a voltage transformer is zero, one of the voltage transformers is controlled to periodically disconnect at a first time interval and continue for a second time interval, and then the voltage transformer is controlled to reconnect; if the sum of the high voltage terminal voltages of the other two voltage transformers is 380V during the first time interval, the fault type at this time is determined to be neutral wire disconnection + single phase disconnection fault.

[0018] When the normally open switch is in the open state, if the high voltage terminal voltage of the three voltage transformers is not zero, one of the voltage transformers is controlled to disconnect periodically at a first time interval and continue for a second time interval, and then the voltage transformer is controlled to connect. If the sum of the voltages of the other two high voltage terminals is 380V during the first time interval, the fault type at this time is determined to be a neutral wire disconnection fault.

[0019] Preferably, the normally open switch is a relay, the first time is 1 minute, and the second time is 3-5 seconds.

[0020] Preferably, the control circuit includes:

[0021] An optocoupler has its first end connected to a 5V level via a first resistor, and its second end connected to the collector of a transistor. The emitter of the transistor is grounded, and the base of the transistor is connected to a microcontroller via a second resistor to receive PWM control information from the microcontroller.

[0022] The third terminal of the optocoupler is connected to the first terminal of the third resistor, and its fourth terminal is connected to the trigger terminal of a bidirectional thyristor.

[0023] A fourth resistor is connected between the trigger terminal and the first terminal of the bidirectional thyristor, and the second terminal of the bidirectional thyristor is connected to the second terminal of the third resistor; a fifth resistor is connected in series with the first capacitor and then in parallel with the second terminal and the first terminal of the bidirectional thyristor, and the output terminal is led out from the two ends of the series-connected fifth resistor and the first capacitor.

[0024] Preferably, the microcontroller further includes:

[0025] The conversion unit is used to convert the DC voltage output by each voltage transformer and the voltage ratio parameters of the voltage transformer to obtain the current phase voltage of the high-voltage side of the voltage transformer.

[0026] Implementing the embodiments of the present invention has the following beneficial effects:

[0027] This invention provides a power line tampering prevention alarm device, solving the problem of theft prevention in existing power distribution network lines. This invention uses a microcontroller in conjunction with voltage transformers and control circuits to comprehensively detect line breaks, quickly identifying the type of fault. It can promptly send alarm SMS messages after the distribution network line is cut by thieves. The logic is simple and the results are reliable.

[0028] Implementing the embodiments of this invention offers advantages such as low cost, compact size, and high reliability. It is particularly well-suited to the characteristics of wiring during urban renewal projects and provides excellent anti-theft protection. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of a structure of an embodiment of a power line external damage prevention alarm device provided by the present invention;

[0031] Figure 2 for Figure 1 Schematic diagram of the connection between the medium voltage transformer and the front wire of the distribution line;

[0032] Figure 3 for Figure 1 A schematic diagram of the control circuit. Detailed Implementation

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0034] It should also be noted that, in order to avoid obscuring the invention with unnecessary details, only the structures and / or processing steps closely related to the solution according to the invention are shown in the accompanying drawings, while other details that are not closely related to the invention are omitted.

[0035] During some urban renewal projects, the relocation of users has resulted in no load at the end of the distribution network, which also makes it difficult to detect theft of lines in a timely manner. At the same time, since 10kV and above lines are equipped with complete external damage alarm devices, the stolen lines are often low-voltage overhead lines with a line voltage of 380V.

[0036] The fault caused by line thieves is a broken wire in the line between the low-voltage side of the distribution transformer and the user's meter box; this section of line is usually referred to as the "before-the-meter line." The voltmeter reading will change accordingly depending on the type of fault caused by the thief. Based on these characteristics, the timing and type of the broken wire fault can be detected.

[0037] like Figure 1 The diagram shown illustrates a structural schematic of one embodiment of a power line external damage prevention alarm device provided by the present invention; in conjunction with... Figure 2 and Figure 3As shown, in this embodiment of the invention, the power line external damage alarm device includes at least:

[0038] Three voltage transformers (represented by V1-V3 in the diagram) are connected in a star configuration. The high-voltage side of each voltage transformer is connected to one of the three-phase live wires and the neutral wire of the distribution line. Figure 1 In the circuit, V1 is connected to the A-phase live wire and the neutral wire via a fuse FU, V2 is connected to the C-phase live wire and the neutral wire via a fuse, and V3 is connected to the B-phase live wire and the neutral wire via a fuse. The ground wire on the voltage transformer side is grounded via a normally open switch. In one example of the present invention, the normally open switch may be a controlled relay.

[0039] The rectifier circuit is connected to the low-voltage side of the three voltage transformers respectively, and is used to rectify the low-voltage signal output by each voltage transformer to form a DC voltage.

[0040] The microcontroller receives the rectified DC voltage output from each voltage transformer and comprehensively judges whether the power lines in the power distribution network are faulty and the corresponding fault type based on the DC voltage.

[0041] The control circuit is connected between the microcontroller and the normally open switch and each voltage transformer. It is used to control the opening and closing of the normally open switch according to the command of the microcontroller, and to control the opening and closing between the high voltage side of the voltage transformer and the three-phase live wire.

[0042] The Internet of Things (IoT) module is connected to the microcontroller and is used to send out the power line faults and corresponding fault types detected by the microcontroller.

[0043] More specifically, in embodiments of the present invention, the microcontroller further includes:

[0044] The conversion unit is used to calculate the current phase voltage of the high-voltage side of each voltage transformer based on the DC voltage output of each transformer and the voltage ratio parameters of the transformer. For example, in one case, the ratio of the voltage change parameters of the high-voltage side voltage to the low-voltage side voltage of the voltage transformer is 220 / 4. If the microcontroller reads a voltage value of 3V on the low-voltage side, then the high-voltage side voltage can be calculated as 3 × 220 / 4 = 165V.

[0045] More specifically, in one embodiment of the present invention, the fault types include: single-phase open circuit fault, two-phase open circuit fault, three-phase open circuit fault, neutral wire open circuit fault, neutral wire open circuit + single-phase open circuit fault, neutral wire open circuit + two-phase open circuit fault, and three-phase open circuit fault.

[0046] The microcontroller further determines whether the power line is faulty and the corresponding fault type using the following method:

[0047] When the normally open switch is in the open state, if the high-voltage terminal voltages of all three voltage transformers are detected to be zero, the normally open switch is controlled to close. If the high-voltage terminal voltages of all three voltage transformers remain zero at this time, the current fault type is determined to be a three-phase open circuit fault; if the high-voltage terminal voltage of one voltage transformer is 220V at this time, the current fault type is determined to be a neutral wire open circuit + two-phase open circuit fault. It is understood that in this embodiment of the invention, the normally open switch can only be closed when the high-voltage terminal voltages of all three voltage transformers are detected to be zero. Since this invention is aimed at a distribution network, the line is a 220V line.

[0048] When the normally open switch is in the open state, if the high voltage terminal voltage of the two voltage transformers is zero and the high voltage terminal voltage of the other voltage transformer is 220V, the fault type at this time is determined to be a two-phase open circuit fault.

[0049] When the normally open switch is in the open state, if it is determined that the high voltage terminal voltage of one voltage transformer is zero and the high voltage terminal voltage of the other two voltage transformers is 220V, the fault type at this time is determined to be a single-phase open circuit fault.

[0050] When the normally open switch is in the open state, if it is determined that the high voltage terminal voltage of one voltage transformer is zero, one of the voltage transformers is controlled to periodically disconnect at a first time interval (e.g., 1 minute) and continue for a second time interval (e.g., 3-5 seconds), and then the voltage transformer is controlled to reconnect; if the sum of the high voltage terminal voltages of the other two voltage transformers is 380V during the first time interval, the fault type at this time is determined to be a neutral wire disconnection + single-phase wire disconnection fault.

[0051] When the high-voltage terminal voltages of the three voltage transformers are not zero, one of the voltage transformers is periodically disconnected at a first time interval (e.g., 1 minute) and then connected again at a second time interval (e.g., 3-5 seconds). If the sum of the voltages of the other two high-voltage terminals is 380V during the first time interval, the fault type is determined to be a neutral wire disconnection fault.

[0052] like Figure 2 As shown, the control circuit includes:

[0053] Optocoupler U1 has its first terminal connected to a 5V level through a first resistor R1, and its second terminal connected to the collector of a transistor Q1. The emitter of transistor Q1 is grounded, and the base of transistor Q1 is connected to a microcontroller through a second resistor R2 to receive PWM control information from the microcontroller.

[0054] The third terminal of the optocoupler U1 is connected to the first terminal of the third resistor R3, and its fourth terminal is connected to the trigger terminal of a bidirectional thyristor Q2.

[0055] A fourth resistor R4 is connected between the trigger terminal and the first terminal of the bidirectional thyristor Q2. The second terminal of the bidirectional thyristor is connected to the second terminal of the third resistor R3. A fifth resistor R5 is connected in series with the first capacitor C1 and then in parallel to the second terminal and the first terminal of the bidirectional thyristor Q1. The output terminal is led out from the two ends of the series-connected fifth resistor R5 and the first capacitor C1.

[0056] It is understood that in this embodiment of the invention, the PWM signal originates from a pin of the microcontroller, and the PWM waveform is output through microcontroller programming. The two output terminals (g1, g2) on the right side of the control circuit are connected in series to the circuit to be controlled, functioning as a normally open switch. When the PWM wave is at 5V, the controlled circuit is in a connected state; when the PWM wave is at 0V, the controlled circuit is in a disconnected state. Therefore, this control circuit can also be used to control the connection between the high-voltage side of the voltage transformer and the meter's front line.

[0057] In an embodiment of the invention, the 220V phase voltage on the high-voltage side of one of the three voltage transformers can be converted into the power supply voltage for the microcontroller and its peripheral circuits. Considering that the microcontroller circuit will lose power in the event of a wire breakage due to theft, a backup battery is required to provide power for the IoT module to transmit fault information.

[0058] In a practical example, the STC8A8K64S4A12 microcontroller can be selected, which can fully meet the requirements of this device. This microcontroller has the following characteristics:

[0059] It uses the 8051 core and supports online simulation;

[0060] Operating voltage: 2.0V-5.5V;

[0061] Flash memory: Supports a maximum of 64KB of flash space, supports user-configurable EEPROM size, 512-byte single-page erase, erase / write cycles of over 100,000, and supports microcontroller emulation;

[0062] Interrupts: Provides 22 terminal sources and 4 interrupt priorities;

[0063] Digital peripherals: 5 16-bit timers, 4 high-speed serial ports, 8 groups of 15-bit enhanced PWM, 4 groups of PCA modules, SPI;

[0064] Analog peripherals: ADC, supporting 12-bit precision 16-channel analog-to-digital conversion;

[0065] GPIO: Up to 59 GPIOs, all of which support the following four modes: quasi-bidirectional port mode, push-pull output mode, open-drain output mode, and high-impedance input mode.

[0066] The IoT module model WH-NB73-CT can be selected, and this IoT module has the following characteristics:

[0067] VCC: 3.1-4.2V, VDD: 5.0-16.0V;

[0068] Speed: 14.4Kbps-57.6Kbps;

[0069] Data bits: 8 bits, Stop bits: 1;

[0070] Maximum transmit power: 23dBm, with a tolerance of ±2dBm;

[0071] Number of ports: TTL*1.

[0072] The working principle of this invention is as follows: First, at least one power line tampering alarm device is installed in the power distribution network of the old city renovation project. The live and neutral wires are led from the user's meter installation point, stepped down by a voltage transformer, and then connected to a microcontroller and its peripheral circuits to supply power. When a thief attempts to steal, the line is cut, and the microcontroller detects a change in the low-voltage side value of the voltage transformer. It then comprehensively judges the fault type and sends a fault-related signal to the IoT module. Upon receiving the signal, the IoT module sends the fault-related information to the cloud backend. The relevant information in the cloud backend is displayed on a mobile app, allowing power grid operation and maintenance personnel to edit the device information via the mobile software. They can also obtain relevant device information by scanning a QR code.

[0073] The solution of this invention solves the problem of theft prevention of distribution network lines. It can trigger an on-site alarm to notify security guards and send text messages to relevant staff the moment the line is stolen, so as to facilitate timely detection of theft and recovery of related losses as soon as possible.

[0074] Implementing the embodiments of the present invention has the following beneficial effects:

[0075] This invention provides a power line tampering prevention alarm device, solving the problem of theft prevention in existing power distribution network lines. This invention uses a microcontroller in conjunction with voltage transformers and control circuits to comprehensively detect line breaks, quickly identifying the type of fault. It can promptly send alarm SMS messages after the distribution network line is cut by thieves. The logic is simple and the results are reliable.

[0076] Implementing the embodiments of this invention offers advantages such as low cost, compact size, and high reliability. It is particularly well-suited to the characteristics of wiring during urban renewal projects and provides excellent anti-theft protection.

[0077] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of the claims of the present invention. Therefore, any equivalent changes or modifications made without departing from the spirit disclosed in the present invention should be included within the scope of the claims of the present invention.

Claims

1. A power line external damage prevention alarm device, characterized in that, At least including: Three voltage transformers are connected in a star configuration. The high-voltage side of each voltage transformer is connected to one of the three-phase live wires and the neutral wire in front of the distribution line meter. The ground wire on the voltage transformer side is grounded through a normally open switch. A rectifier circuit is connected to the low-voltage side of each of the three voltage transformers to rectify the low-voltage signal output by each voltage transformer to form a DC voltage. The microcontroller receives the rectified DC voltage output from each voltage transformer and uses the DC voltage to determine whether the power lines in the distribution network are faulty and the corresponding fault type. The control circuit is connected between the microcontroller and the normally open switch and each voltage transformer. It is used to control the opening and closing of the normally open switch according to the command of the microcontroller, and to control the opening and closing between the high voltage side of the voltage transformer and the three-phase live wire. The Internet of Things (IoT) module is connected to the microcontroller and is used to send out the power line faults and corresponding fault types detected by the microcontroller. The microcontroller further determines whether the power line is faulty and the corresponding fault type using the following method: When the normally open switch is in the open state, if the high voltage terminal voltage of all three voltage transformers is detected to be zero, the control will close the normally open switch. If the high voltage terminal voltage of all three voltage transformers remains zero at this time, the current fault type is determined to be a three-phase open circuit fault. If the high voltage terminal voltage of one voltage transformer is 220V at this time, the current fault type is determined to be a neutral wire open circuit + two-phase open circuit fault. When the normally open switch is in the open state, if the high voltage terminal voltage of the two voltage transformers is zero and the high voltage terminal voltage of the other voltage transformer is 220V, the fault type at this time is determined to be a two-phase open circuit fault. When the normally open switch is in the open state, if it is determined that the high voltage terminal voltage of one voltage transformer is zero, and the high voltage terminal voltage of the other two voltage transformers is 220V, the fault type at this time is determined to be a single-phase open circuit fault. When the normally open switch is in the open state, when it is determined that the high voltage terminal voltage of a voltage transformer is zero, one of the voltage transformers is controlled to periodically disconnect at a first time interval and continue for a second time interval, and then the voltage transformer is controlled to reconnect; if the sum of the high voltage terminal voltages of the other two voltage transformers is 380V during the first time interval, the fault type at this time is determined to be neutral wire disconnection + single phase disconnection fault. When the normally open switch is in the open state, if the high voltage terminal voltage of the three voltage transformers is not zero, one of the voltage transformers is controlled to disconnect periodically at a first time interval and continue for a second time interval, and then the voltage transformer is controlled to connect. If the sum of the voltages of the other two high voltage terminals is 380V during the first time interval, the fault type at this time is determined to be a neutral wire disconnection fault.

2. The apparatus as claimed in claim 1, characterized in that, The fault types include: single-phase open circuit fault, two-phase open circuit fault, three-phase open circuit fault, neutral wire open circuit fault, neutral wire open circuit + single-phase open circuit fault, neutral wire open circuit + two-phase open circuit fault, and three-phase open circuit fault.

3. The apparatus as described in claim 2, characterized in that, The normally open switch is a relay, the first time is 1 minute, and the second time is 3-5 seconds.

4. The apparatus as described in claim 3, characterized in that, The control circuit includes: An optocoupler has its first end connected to a 5V level via a first resistor, and its second end connected to the collector of a transistor. The emitter of the transistor is grounded, and the base of the transistor is connected to a microcontroller via a second resistor to receive PWM control information from the microcontroller. The third terminal of the optocoupler is connected to the first terminal of the third resistor, and its fourth terminal is connected to the trigger terminal of a bidirectional thyristor. A fourth resistor is connected between the trigger terminal and the first terminal of the bidirectional thyristor, and the second terminal of the bidirectional thyristor is connected to the second terminal of the third resistor; a fifth resistor is connected in series with the first capacitor and then in parallel with the second terminal and the first terminal of the bidirectional thyristor, and the output terminal is led out from the two ends of the series-connected fifth resistor and the first capacitor.

5. The apparatus as described in claim 4, characterized in that, The microcontroller further includes: The conversion unit is used to convert the DC voltage output by each voltage transformer and the voltage ratio parameters of the voltage transformer to obtain the current phase voltage of the high-voltage side of the voltage transformer.

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