Online energy taking device, system and method for direct current overhead transmission line

Abstract

The invention relates to the technical field of high voltage, in particular to an on-line energy taking device, system and method of a direct current overhead transmission line, ground wires of the direct current overhead transmission line are grounded one by one, the device comprises an energy taking module and a power management module, the energy taking module is installed on any ground wire of the direct current overhead transmission line, and the power management module is installed on any ground wire of the direct current overhead transmission line. The energy taking module performs on-line energy taking by using the ground wire harmonic current of the direct current overhead transmission line; and the power supply management module is connected with the energy taking module, stores the energy taken by the energy taking module on line, and supplies energy to the on-line monitoring terminal of the direct-current overhead transmission line by using the energy. Therefore, the problems of large installation difficulty, too low energy-taking power and difficult maintenance of the energy-taking device of an online energy-taking scheme in the related technology are solved.

Description

Technical Field

[0001] The present application relates to the technical field of high voltage, and particularly to an on-line energy taking device, system and method for a DC overhead transmission line. Background Art

[0002] Due to the wide coverage of transmission lines, the complex and changeable terrain along the way, the frequent occurrence of extreme weather along the overhead transmission lines, and the unpredictable human factors, etc., transmission line faults have become the main cause of power grid faults. The traditional maintenance method requires manual inspection of each tower along the line. However, since the areas crossed by the line are often inconvenient in transportation, the manual inspection workload is extremely large and the efficiency is low; moreover, the factors causing faults appear for a short time and are random, and some faults are difficult to detect with the naked eye, making the troubleshooting inconvenient; the cost of helicopter line inspection is relatively high, and helicopters cannot be dispatched in bad weather; unmanned aerial vehicle (UAV) line inspection has been widely used in recent years, but the nest for charging the UAV needs to be separately installed with commercial power for power supply, and its application is also restricted by weather factors. For the above reasons, the on-line monitoring technology for overhead transmission lines has received extensive attention and development in recent years, and various on-line monitoring devices have been installed on the overhead line ground wires and towers.

[0003] The on-line monitoring device requires a stable and reliable power supply to ensure its normal operation, while the traditional power supply methods have many defects. The scheme of combining photovoltaic panels and batteries for power supply is difficult to ensure stable power supply in areas with perennial rain or snow-covered areas, and the life of the battery will be greatly reduced in extreme weather, requiring frequent manual maintenance; energy can be obtained by installing a CT (Current Transformer) on the wire, but because it is installed on the wire, the installation and maintenance are both inconvenient, and since the energy taking device is at the high voltage end, it cannot directly supply power to the device installed on the tower at ground potential, and when the CT device installed on the wire is damaged, there is a risk of causing transmission line faults and affecting the normal transmission of electric energy.

[0004] On AC overhead transmission lines, the technology of taking energy by using the induced electromotive force generated by the alternating current of the wire on the ground wire has been widely studied and developed and is currently relatively mature. However, on DC overhead transmission lines, there is no relatively mature on-line energy taking scheme. Summary of the Invention

[0005] The present application provides a device, system and method for on-line energy taking for a DC overhead transmission line in the technical field of high voltage, so as to solve the problems of difficult installation of the related technology on-line energy taking scheme, too low energy taking power, and difficult maintenance of the energy taking device.

[0006] An embodiment of the first aspect of the present application provides an on-line energy-taking device for a DC overhead transmission line. The ground wires of the DC overhead transmission line are grounded at each tower. The on-line energy-taking device includes an energy-taking module and a power management module. The energy-taking module is installed on any ground wire of the DC overhead transmission line. The energy-taking module uses the harmonic current of the ground wire of the DC overhead transmission line to take energy on-line. The power management module is connected to the energy-taking module, stores the energy taken on-line by the energy-taking module, and uses the energy to supply power to the on-line monitoring terminal of the DC overhead transmission line.

[0007] Optionally, the energy-taking module is a current transformer. An alternating harmonic current of the ground wire generates an alternating magnetic field in the space around the wire, and then an induced electromotive force is generated in the ground wire loop of the transmission line. The induced electromotive force generates a current in the ground wire loop. When the current on the ground wire flows through the current transformer, a voltage is generated at the secondary winding port of the current transformer.

[0008] Optionally, the power management module includes a power management component and a storage battery. The voltage generated at the secondary winding port of the current transformer charges the storage battery.

[0009] Optionally, the on-line energy-taking device of the DC overhead transmission line includes a rectifying and filtering component disposed between the power management component and the current transformer.

[0010] Optionally, the energy-taking module enters a saturation state when the transmission line is struck by lightning.

[0011] Optionally, the power management module is installed on the tower of the DC overhead transmission line.

[0012] An embodiment of the second aspect of the present application provides an on-line monitoring system for a DC overhead transmission line, including an on-line monitoring terminal and the on-line energy-taking device of the DC overhead transmission line in the first aspect. The on-line energy-taking device takes energy on-line from the DC overhead transmission line and supplies power to the on-line monitoring terminal.

[0013] Optionally, the on-line monitoring terminal includes a data acquisition device, a data transmission device, and a network communication device.

[0014] Optionally, the data acquisition device includes at least one of a tension monitoring unit, an inclination monitoring unit, a micro-meteorological monitoring unit, and an image monitoring unit.

[0015] An embodiment of the third aspect of the present application provides an on-line monitoring method for a DC overhead transmission line. The method uses the on-line monitoring system of the DC overhead transmission line in the second aspect to perform on-line monitoring, including the following steps: obtaining the target monitoring duration of the DC overhead transmission line; regularly waking up the on-line energy-taking device based on the target monitoring duration. The on-line energy-taking device supplies power to the on-line monitoring terminal; and performing on-line monitoring of the DC overhead transmission line based on the on-line monitoring terminal.

[0016] Accordingly, the present application has the following beneficial effects:

[0017] In the embodiment of the present application, by installing the energy harvesting module on any ground wire of the DC overhead transmission line, the energy harvesting module utilizes the harmonic current of the ground wire of the DC overhead transmission line for on-line energy harvesting. The power management module is connected to the energy harvesting module to store the energy harvested on-line by the energy harvesting module, and the energy is used to supply power to the on-line monitoring terminal of the DC overhead transmission line. There is no need to be equipped with additional overvoltage protection devices, and the design is simple and reliable. The on-line energy harvesting power exceeding 0.1 W is achieved, and it supports the minute-level real-time monitoring of low-power on-line energy harvesting devices. Accordingly, the problems in the related art that the installation of the on-line energy harvesting scheme is difficult, the energy harvesting power is too low, and the maintenance of the energy harvesting device is difficult are solved.

[0018] Some of the additional aspects and advantages of the present application will be given in the following description, some will become obvious from the following description, or will be understood through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above and / or additional aspects and advantages of the present application will become obvious and easy to understand from the following description of the embodiments in conjunction with the drawings, where:

[0020] Figure 1 Two on-line energy harvesting methods provided for the related art;

[0021] Figure 2 Schematic structural diagram of an on-line energy harvesting device for a DC overhead transmission line according to an embodiment of the present application;

[0022] Figure 3 Schematic diagram of an energy harvesting device installed on a ground wire according to an embodiment of the present application;

[0023] Figure 4 Schematic structural diagram of an on-line energy harvesting device according to an embodiment of the present application;

[0024] Figure 5 Schematic diagram of the physical process of the operation of an on-line energy harvesting device according to an embodiment of the present application;

[0025] Figure 6 Schematic diagram of a line structure according to an embodiment of the present application;

[0026] Figure 7 Schematic diagram of the waveform of the ground wire current according to an embodiment of the present application;

[0027] Figure 8 Schematic diagram of the circuit model of the ground wire energy harvesting according to an embodiment of the present application;

[0028] Figure 9Simplified model diagram of a ground wire energy extraction circuit provided according to an embodiment of the present application;

[0029] Figure 10 Structural schematic diagram of a CT provided according to an embodiment of the present application;

[0030] Figure 11 Ground wire current spectrum diagram provided according to an embodiment of the present application;

[0031] Figure 12 Structural example diagram of an on-line energy extraction system for a DC overhead transmission line provided according to an embodiment of the present application;

[0032] Figure 13 Flow example diagram of an on-line energy extraction method for a DC overhead transmission line provided according to an embodiment of the present application. Detailed implementation manners

[0033] The embodiments of the present application will be described in detail below. The examples of the embodiments are shown in the drawings, where the same or similar reference numerals denote the same or similar elements or elements with the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary and are intended to explain the present application, and should not be construed as a limitation to the present application.

[0034] On AC overhead transmission lines, the technology of extracting energy using the induced electromotive force generated by the alternating current of the conductor on the ground wire has been widely studied and developed. However, on DC overhead transmission lines, there is no relatively mature on-line energy extraction scheme. In the aspect of on-line energy extraction for DC overhead transmission lines, one of the related technologies can use a current transformer installed on the conductor of the DC transmission line to extract energy using the induced electromotive force generated by the harmonic current in the conductor of the DC transmission line, but the implementation difficulty is large, and it cannot supply power to the equipment at ground potential; another related technology proposes two energy extraction schemes based on insulator leakage current and based on space ion flow, as Figure 1 shown, but its device structure is complex, and the energy extraction power is small, making it difficult to apply.

[0035] In view of the defects of the above-mentioned related technologies, the embodiments of the present application propose an on-line energy extraction device, system and method for a DC overhead transmission line, which will be described in detail below.

[0036] The on-line energy acquisition device, system and method for a DC overhead transmission line according to an embodiment of the present application will be described below with reference to the accompanying drawings. In view of the problems in the related art on-line energy acquisition solutions, such as difficult installation, too low energy acquisition power, and difficult maintenance of the energy acquisition device, the present application provides an on-line energy acquisition device for a DC overhead transmission line. In this device, by installing the energy acquisition module on any ground wire of the DC overhead transmission line, the energy acquisition module uses the harmonic current of the ground wire of the DC overhead transmission line for on-line energy acquisition, connects the power management module to the energy acquisition module, stores the energy acquired on-line by the energy acquisition module, and uses the energy to supply power to the on-line monitoring terminal of the DC overhead transmission line. There is no need to equip additional overvoltage protection devices, the design is simple and reliable, the on-line energy acquisition power exceeds 0.1 W, and it supports minute-level real-time monitoring of low-power on-line energy acquisition devices. Thus, the problems in the related art on-line energy acquisition solutions, such as difficult installation, too low energy acquisition power, and difficult maintenance of the energy acquisition device, are solved.

[0037] Specifically, Figure 2 FIG. is a schematic structural diagram of an on-line energy acquisition device for a DC overhead transmission line provided by an embodiment of the present application.

[0038] As Figure 2 shown, the on-line energy acquisition device 10 for the DC overhead transmission line includes: a ground wire 101 of the DC overhead transmission line, an energy acquisition module 102, and a power supply module 103.

[0039] Among them, the ground wire 101 of the DC overhead transmission line is grounded at each pole, the energy acquisition module 102 is installed on any ground wire 101 of the DC overhead transmission line, and the energy acquisition module 102 uses the harmonic current of the ground wire 101 of the DC overhead transmission line for on-line energy acquisition; the power management module 103 is connected to the energy acquisition module 102, stores the energy acquired on-line by the energy acquisition module 102, and uses the energy to supply power to the on-line monitoring terminal of the DC overhead transmission line.

[0040] Among them, the fact that the ground wire 101 of the DC overhead transmission line is grounded at each pole means that each tower of the transmission line directly grounds the ground wire to form a grounding point to protect the transmission line from overvoltage phenomena such as lightning strikes.

[0041] It can be understood that the embodiment of the present application is applicable to a DC overhead transmission line adopting the method of grounding at each pole. The energy acquisition module 102 is installed on the selected ground wire 101 of the DC overhead transmission line, and the alternating magnetic field generated by the harmonic current flowing through the ground wire 101 is used for energy collection. The collected energy is stored and managed by the power management module 103, and the energy is used to supply power to the on-line monitoring terminal of the DC overhead transmission line. This design simplifies the installation process and reduces the maintenance cost at the same time.

[0042] In the embodiment of the present application, the energy harvesting module 102 is a current transformer. Among them, the alternating ground wire harmonic current generates an alternating magnetic field in the space around the wire, and then induces an electromotive force in the ground wire loop of the transmission line. The induced electromotive force generates a current in the ground wire loop. When the current on the ground wire flows through the current transformer, a voltage is generated at the secondary winding port of the current transformer.

[0043] Among them, the alternating ground wire harmonic current refers to the non - DC component current generated in the DC transmission line due to various reasons. These currents will generate a changing magnetic field in the space around the wire; the current transformer can obtain energy by inducing the alternating magnetic field in the ground wire and convert it into an available voltage output.

[0044] It can be understood that the energy harvesting module 102 in the embodiment of the present application is a current transformer, which is installed on the ground wire 101 of the DC overhead transmission line. The harmonic current in the DC transmission line generates an alternating magnetic field in the surrounding space. According to the electromagnetic induction principle, the current transformer induces the alternating magnetic field in the ground wire to obtain energy and converts it into an available voltage output at the secondary winding port of the current transformer, making clever use of the characteristics of the transmission line itself to achieve effective power supply for the on - line monitoring terminal.

[0045] In the embodiment of the present application, the power management module 103 includes a power management component and a storage battery. Among them, the voltage generated at the secondary winding port of the current transformer charges the storage battery.

[0046] Among them, the power management component is an electronic component used to regulate, control, and distribute electric power, ensuring the safe and effective charging process of the storage battery and being able to provide a stable power output to the on - line monitoring terminal.

[0047] It can be understood that the power management module 103 in the embodiment of the present application includes a power management component for regulating and controlling electric power and a storage battery. The voltage generated at the secondary winding port of the current transformer is used to charge the storage battery in the power management module 103, and through the power management component for regulating, controlling, and distributing electric power, the power management module 103 can effectively store the obtained energy and provide a stable and reliable power supply for the on - line monitoring terminal installed on the tower.

[0048] In the embodiment of the present application, the on - line energy harvesting device of the DC overhead transmission line further includes: a rectifying and filtering component arranged between the power management component and the current transformer.

[0049] Among them, the rectifying and filtering component is used to convert the AC voltage generated by the secondary winding of the current transformer into a DC voltage and filter out the fluctuations and noises in the voltage, so as to provide a more stable and smooth DC power output.

[0050] It can be understood that the embodiment of the present application further includes a rectifying and filtering element disposed between the power management element and the current transformer. The alternating voltage generated at the secondary winding port of the current transformer will be processed by the rectifying and filtering element and converted into a more stable and smooth direct current voltage. This direct current voltage is used to charge the storage battery in the power management module 103, enabling the entire system to not only effectively obtain energy from the transmission line but also ensure that the power provided to the on-line monitoring device is both stable and reliable.

[0051] In the embodiment of the present application, the energy harvesting module 102 enters a saturation state when the transmission line is struck by lightning.

[0052] Among them, the saturation state means that for the current transformer, when the input current is too large, such as the extreme current during lightning strike, exceeding its rated value, the current transformer will enter the saturation state. In this state, the magnetic core of the current transformer reaches the magnetic saturation point and can no longer effectively convert the current change into a voltage output, thus playing a role in protecting the subsequent circuit.

[0053] It can be understood that in the embodiment of the present application, when the DC overhead transmission line is struck by lightning, due to the extremely high current generated instantaneously flowing through the ground wire 101 of the DC overhead transmission line, the energy harvesting module 102, that is, the current transformer installed on the ground wire, will enter the saturation state. In this case, the magnetic core of the current transformer reaches the magnetic saturation point due to the excessive current, resulting in its inability to continue to work normally and effectively convert the current change into a voltage output. This mechanism actually plays a protective role and prevents the extreme current from damaging the subsequent power management module and the on-line monitoring device connected thereto. Therefore, this design can not only obtain energy from the harmonic current of the ground wire during daily operation but also automatically enter the protection mode when encountering extreme events such as lightning strikes, ensuring the safety and reliability of the entire system.

[0054] In the embodiment of the present application, the power management module 103 is installed on the DC overhead transmission line tower.

[0055] Among them, the tower is a structure that supports the conductors and ground wires of the transmission line, usually made of metal or concrete, and is distributed along the transmission line.

[0056] According to the on-line energy harvesting device for DC overhead transmission lines proposed in the embodiment of the present application, by installing the energy harvesting module on any ground wire of the DC overhead transmission line, the energy harvesting module uses the harmonic current of the ground wire of the DC overhead transmission line for on-line energy harvesting, connects the power management module to the energy harvesting module, stores the energy harvested on-line by the energy harvesting module, and uses the energy to supply power to the on-line monitoring terminal of the DC overhead transmission line. There is no need to equip additional overvoltage protection devices. The design is simple and reliable, has a relatively high on-line energy harvesting power, and supports minute-level real-time monitoring of low-power on-line energy harvesting devices.

[0057] The online energy extraction device for DC overhead transmission lines will be further described below through a specific embodiment.

[0058] The online energy extraction device for DC transmission lines proposed in this embodiment is applicable to DC overhead transmission lines where both ground wires are grounded at each tower. The energy extraction module in the energy extraction device is installed on one of the ground wires, and the power management module is connected to the energy extraction module and installed on the tower to supply power to the line online monitoring device, as Figure 3 shown.

[0059] Among them, the energy extraction module is a current transformer installed on the ground wire of the overhead line, and the power management module is composed of a storage battery and supporting power management devices, and its structure is as Figure 4 shown.

[0060] When the DC overhead transmission line is operating normally, due to the harmonic current in the bipolar DC conductors, the alternating harmonic current will generate an alternating magnetic field in the space around the conductors, and then an induced electromotive force will be generated in the ground wire loop of the transmission line. For the ground wire operation mode where both ground wires are grounded at each tower, the induced electromotive force will further generate a current in the ground wire loop. When the current on the ground wire flows through the current transformer, a voltage will be generated at the secondary winding port of the current transformer, which can be used to charge the supporting storage battery, thereby supplying power to the online monitoring device.

[0061] Specifically, the schematic diagram of the physical process during the operation of the device is as Figure 5 shown: There are harmonic currents of various frequencies in the conductors, there is electromagnetic coupling between the conductors and the ground wires, an induced electromotive force is generated in the ground wire loop of the overhead line, the ground wires grounded at each tower form a loop, there are harmonic currents in the ground wires, the harmonic currents in the ground wires are induced by the current transformer installed on the ground wire to generate an AC voltage, the AC voltage is converted into a stable voltage through the rectification and filtering module to charge the storage battery, and the charge and discharge management module conducts power distribution and management to realize the power supply of the online monitoring device.

[0062] Specifically, using the above online energy extraction device for DC transmission lines, based on the settings of a certain ±500 kV bipolar DC project, the positions of the phase conductors and ground wires are as Figure 6 shown, where the phase conductors are six - split conductors with a sub - conductor spacing of 0.4 m, the grounding method of the ground wires is joint - by - joint grounding at each tower, the tower grounding resistance is 15, and the line span is 400 m.

[0063] The harmonic current of the conductors is set based on the actual operation data of the line. By calculating the mutual inductance coupling between the phase conductors and ground wires, the time - domain waveform of the harmonic current on one of the ground wires is obtained as Figure 7 shown.

[0064] Perform circuit modeling on the energy extraction device as Figure 8As shown, where CT is equivalent to a transformer, and its primary turns are 1 (ground wire).

[0065] Where R m , L m correspond to the exciting inductance and iron loss of CT; R1 and L1 represent the resistance and leakage inductance of the primary side (ground wire side); R2 and L2 represent the resistance and leakage inductance of the secondary side (load side); N1 and N2 represent the turns of the primary and secondary sides of CT respectively, and for the ground wire CT in the energy-taking scenario, N1 = 1. The harmonic power supply and equivalent inductance are used to characterize the port characteristics at the ground wire where CT is installed. Through electromagnetic field simulation calculation, the equivalent inductance of the ground wire can be calculated to be about 0.05 H. For normal operation, for CT in the non-saturated region, the main influencing factor is L m , so Figure 8 can be simplified to obtain Figure 9 .

[0066] In this embodiment, it is considered that CT has a bushing structure, as Figure 10 shown, its inner diameter is D1, outer diameter is D2, and thickness is h, then L m can be calculated according to the following formula:

[0067]

[0068] where k (k≈0.92 - 0.96) is a coefficient related to the magnetic field distribution in the CT core, μ = μ r μ0, is the magnetic permeability when CT is working. Substituting the dimensions of a general CT (in this embodiment, D2 = 70 mm, D1 = 40 mm, μ r ≈1.7×10 4 ), L m ≈1×10 -4 H can be calculated.

[0069] In the equivalent circuit, the voltage of the power supply at frequency ω is E, and the value of the ground wire equivalent inductance is L eq . Using the phasor method, the voltage across the load resistance can be calculated as:

[0070]

[0071] According to the above formula, the voltage across the load in the time domain The average power on the load is given by the following formula:

[0072]

[0073] Based on the measured wire current waveforms at different times, the ground wire current frequency spectrum diagrams at different times are obtained through simulation calculation, as Figure 11As shown, the energy extraction power can be calculated, as shown in Table 1. Table 1 is the energy extraction power table for different time periods. In the calculation, the load resistance R L = 20 Ω, and the exciting inductance L of the CT m ≈ 1×10 -4 H, and the CT transformation ratio N = 1.

[0074] Table 1

[0075] Time period Power for energy extraction (W) 1 0.1485 2 0.1381 3 0.1017 4 0.1313 5 0.1128

[0076] Generally speaking, the basic power requirements for on-line monitoring devices of transmission lines are as follows:

[0077] 1) Data acquisition device: < 1 W;

[0078] 2) Data transmission and network communication device: < 2 W;

[0079] 3) Standby static power consumption of the device: < 1 W;

[0080] 4) Power consumption of the whole set of terminal devices for on-line acquisition + data transmission: < 3 W.

[0081] Referring to the above power requirement situation, the actual power consumption when the on-line monitoring device acquires and transmits data is 2.5 W. Considering factors such as transmission loss, the energy extraction power of the energy extraction device is recorded as 0.1 W. Then, with ultra-low power consumption and timed wake-up, state monitoring can be achieved once a minute.

[0082] Since the device is installed on the ground wire of the overhead transmission line and is not directly connected to the ground wire, when the transmission line is struck by lightning, the energy extraction device will enter a saturated state, thus protecting the components at the back end of the energy extraction device from being damaged. Therefore, this energy extraction method has natural advantages in lightning protection.

[0083] Secondly, refer to the accompanying drawings to describe the on-line monitoring system of the DC overhead transmission line according to the embodiments of the present application.

[0084] Figure 12 is a schematic structural diagram of the on-line monitoring system of the DC overhead transmission line according to the embodiments of the present application.

[0085] As Figure 12 shown, the on-line monitoring system 20 of the DC overhead transmission line includes: an on-line monitoring terminal 201 and an on-line energy extraction device 10 of the DC overhead transmission line.

[0086] Among them, the on-line energy extraction device 10 extracts energy from the DC overhead transmission line online to supply energy to the on-line monitoring terminal 201.

[0087] It can be understood that the embodiment of the present application includes two main parts: an on-line monitoring terminal 201 and an on-line power-taking device 10 for a DC overhead transmission line. The on-line power-taking device 10 specifically provides the required power for the on-line monitoring terminal 201, enabling the on-line monitoring terminal 201 to operate without an external power source or battery replacement, greatly improving the autonomy and reliability of the system, and at the same time reducing the maintenance cost.

[0088] In the embodiment of the present application, the on-line monitoring terminal 201 includes a data acquisition device, a data transmission device, and a network communication device.

[0089] Among them, the data acquisition device will be described in detail below and will not be elaborated here; the data transmission device is responsible for preliminarily processing and packaging the information obtained by the data acquisition device and preparing to send it out through a suitable communication method; the network communication device, as a bridge connecting the on-line monitoring terminal and the remote monitoring center, provides the necessary communication means to ensure that the collected data can be transmitted to the monitoring center in a timely and accurate manner. Depending on the actual application scenario, wireless communication such as GPRS (General Packet Radio Service), 3G / 4G, satellite communication, etc. or wired communication methods can be used.

[0090] It can be understood that the on-line monitoring terminal 201 of the embodiment of the present application includes a data acquisition device, a data transmission device, and a network communication device. Through the close cooperation of the three devices, a series of tasks from data acquisition, processing to transmission are jointly completed, providing important technical support for the safe and stable operation of the power system.

[0091] In the embodiment of the present application, the data acquisition device includes at least one of a tension monitoring unit, an inclination monitoring unit, a micro-meteorological monitoring unit, and an image monitoring unit.

[0092] Among them, the tension monitoring unit is used to monitor the tension change of the transmission conductor. By real-time monitoring of the conductor tension, it can help predict potential risks, such as the impact of strong winds, ice and snow loads, etc. on the transmission line; the inclination monitoring unit is used to measure the inclination angle of the tower or transmission conductor to help judge whether the tower foundation is stable and whether there is an inclination risk; the micro-meteorological monitoring unit is used to monitor the micro-climate environment around the transmission line, including parameters such as temperature, humidity, wind speed, and wind direction, and can be used to warn of the damage that may be caused by bad weather; the image monitoring unit can capture real-time images or videos of the transmission line and its surrounding environment through devices such as cameras.

[0093] It can be understood that the data acquisition device in the embodiments of the present application includes at least one of a tension monitoring unit, an inclination monitoring unit, a micro-meteorological monitoring unit, and an image monitoring unit. These devices provide rich data support for the online monitoring terminal, thereby realizing the full-range monitoring of the operating state of the transmission line, helping to improve the safety and reliability of the power transmission system, and timely discovering and solving potential problems.

[0094] It should be noted that the foregoing explanation of the embodiments of the online monitoring device for DC overhead transmission lines also applies to the online monitoring system for DC overhead transmission lines in this embodiment, and will not be elaborated here.

[0095] According to the online monitoring system for DC overhead transmission lines provided by the embodiments of the present application, the online energy harvesting device specifically provides the required power for the online monitoring terminal, enabling the online monitoring terminal to operate without an external power source or battery replacement, greatly improving the autonomy and reliability of the system, and at the same time reducing the maintenance cost.

[0096] Figure 13 FIG. is a schematic flow chart of the online monitoring method for DC overhead transmission lines provided by the embodiments of the present application. The method uses the above-mentioned online monitoring system for DC overhead transmission lines for online monitoring, including the following steps:

[0097] In step S301, the target monitoring duration of the DC overhead transmission line is obtained.

[0098] Among them, to obtain the target monitoring duration of the DC overhead transmission line, it needs to be specifically set with reference to the power demand situation of the above-mentioned online monitoring terminal, and no specific limitation is made here. For example, when the actual power consumption of the online monitoring device for data collection and transmission is 2.5W, considering factors such as transmission loss, and the energy harvesting power of the energy harvesting device is recorded as 0.1W, then the target monitoring duration is once per minute.

[0099] In step S302, the online energy harvesting device is periodically awakened based on the target monitoring duration, where the online energy harvesting device supplies power to the online monitoring terminal.

[0100] It can be understood that the embodiments of the present application design a mechanism for periodically awakening the online energy harvesting device based on the target monitoring duration. The online energy harvesting device is awakened by the target monitoring duration to supply power to the online monitoring terminal, reasonably arranging the working cycle of the online monitoring terminal to ensure that it can maximize the use of limited energy resources while meeting the monitoring requirements.

[0101] In step S303, the DC overhead transmission line is monitored online based on the online monitoring terminal.

[0102] It can be understood that, in the embodiments of the present application, the online energy-taking device is periodically woken up based on the target monitoring duration to perform online monitoring on the DC overhead transmission line, so as to ensure that the state of the transmission line can be monitored in real time and accurately, realize the all-round monitoring of the operating state of the transmission line, contribute to improving the safety and reliability of the power transmission system, timely discover and solve potential problems, greatly improve the autonomy and reliability of the system, and at the same time reduce the maintenance cost.

[0103] It should be noted that the foregoing explanation of the embodiments of the online monitoring device for the DC overhead transmission line also applies to the online monitoring method for the DC overhead transmission line in this embodiment, and will not be elaborated here.

[0104] According to the online monitoring method for the DC overhead transmission line provided by the embodiments of the present application, by obtaining the target monitoring duration of the DC overhead transmission line, the online energy-taking device is periodically woken up based on the target monitoring duration to supply energy to the online monitoring terminal, and the online monitoring terminal is used to perform online monitoring on the DC overhead transmission line, realizing online energy-taking and sufficient energy-taking power, ensuring that the state of the transmission line can be monitored in real time and accurately, realizing the all-round monitoring of the operating state of the transmission line, contributing to improving the safety and reliability of the power transmission system, timely discovering and solving potential problems, greatly improving the autonomy and reliability of the system, and at the same time reducing the maintenance cost.

[0105] In the description of this specification, the descriptions referring to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms are not necessarily directed to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or N embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0106] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "N" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0107] Any process or method description depicted in a flowchart or otherwise described herein may be understood to represent a module, segment, or portion of code including one or more executable instructions for implementing a customized logic function or process. The scope of the preferred embodiments of the present application includes additional implementations where functions may be executed in a substantially simultaneous manner or in a reverse order according to the functions involved, rather than in the order shown or discussed. This should be understood by those skilled in the art to which the embodiments of the present application pertain.

[0108] It should be understood that various parts of the present application may be implemented by hardware, software, firmware, or a combination thereof. In the above-described embodiments, the steps or methods may be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, any one or a combination of the following techniques well known in the art may be used: discrete logic circuits having logic gate circuits for implementing logical functions on data signals, application specific integrated circuits having appropriate combinational logic gate circuits, programmable gate arrays, field programmable gate arrays, and the like.

[0109] Those of ordinary skill in the art of this technology can understand that all or part of the steps carried by the methods for implementing the above embodiments can be completed by instructing relevant hardware through a program. The above program can be stored in a computer-readable storage medium. When the program is executed, it includes one or a combination of the steps of the method embodiments.

[0110] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present application. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present application.

Claims

1. An on-line energy extraction device for a DC overhead transmission line, characterized in that, The ground wires of the DC overhead transmission line are grounded at each tower. Among them, the on-line energy acquisition device includes: an energy acquisition module and a power management module. The energy acquisition module is installed on any ground wire of the DC overhead transmission line. Among them, the energy acquisition module uses the harmonic current of the ground wire of the DC overhead transmission line for on-line energy acquisition; the power management module is connected to the energy acquisition module, stores the energy acquired on-line by the energy acquisition module, and uses the energy to supply power to the on-line monitoring terminal of the DC overhead transmission line.

2. The online energy extraction device for a DC overhead transmission line according to claim 1, characterized in that, The energy acquisition module is a current transformer. Among them, the alternating harmonic current of the ground wire generates an alternating magnetic field in the space around the wire, and then generates an induced electromotive force in the ground wire loop of the transmission line. The induced electromotive force generates a current in the ground wire loop. When the current on the ground wire flows through the current transformer, a voltage is generated at the secondary winding port of the current transformer.

3. The online energy-taking device for a DC overhead transmission line according to claim 2, wherein, The power management module includes a power management component and a storage battery. Among them, the voltage generated at the secondary winding port of the current transformer charges the storage battery.

4. The on-line energy extraction device for a DC overhead transmission line according to claim 3, characterized in that, It further includes: a rectifying and filtering component arranged between the power management component and the current transformer.

5. The online energy extraction device for DC overhead transmission lines according to claim 1, characterized in that, The energy acquisition module enters a saturation state when the transmission line is struck by lightning.

6. The online energy-taking device for a DC overhead transmission line according to claim 1, characterized in that, The power management module is installed on the tower of the DC overhead transmission line.

7. An on-line monitoring system for a DC overhead transmission line, characterized in that, It includes: an on-line monitoring terminal; the on-line energy acquisition device of the DC overhead transmission line according to any one of claims 1-6. Among them, the on-line energy acquisition device acquires energy from the DC overhead transmission line on-line and supplies power to the on-line monitoring terminal.

8. The on-line monitoring system for a DC overhead transmission line according to claim 7, characterized in that, The on-line monitoring terminal includes a data acquisition device, a data transmission device, and a network communication device.

9. The on-line monitoring system for a DC overhead transmission line according to claim 8, characterized in that The data acquisition device includes at least one of a tension monitoring unit, an inclination monitoring unit, a micro-meteorological monitoring unit, and an image monitoring unit.

10. An on-line monitoring method for a DC overhead transmission line, characterized in that, The method uses the on-line monitoring system of the DC overhead transmission line according to any one of claims 7-9 for on-line monitoring. Among them, the method includes the following steps: acquire the target monitoring duration of the DC overhead transmission line; timely wake up the on-line energy acquisition device based on the target monitoring duration. Among them, the on-line energy acquisition device supplies power to the on-line monitoring terminal; carry out on-line monitoring of the DC overhead transmission line based on the on-line monitoring terminal.

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