Cable sheath circulating current online monitoring and suppression integrated system

Abstract

The present invention discloses a comprehensive system for online monitoring and suppression of cable sheath circulating current. The comprehensive system for online monitoring and suppression of cable sheath circulating current includes an acquisition module, a main control module, and an automatic switching module; the acquisition module includes a sheath current acquisition unit for detecting sheath circulating current and a load current acquisition unit for detecting load current, and the main control module is used to obtain the sheath circulating current and load current; the automatic switching module includes a current suppression unit and a switch unit, and the main control module is used to control the current suppression unit to be connected between the sheath terminal and the ground when the sheath circulating current is greater than a preset proportion of the load current and the load current is lower than a preset current limit; the main control module is used to control the current suppression unit to be disconnected when the load current is greater than the preset current limit, so that the sheath terminal is not grounded through the current suppression unit. By adopting the above scheme, the safety of the system is improved, monitoring is more convenient, and effective suppression can be carried out in a timely manner when the sheath circulating current exceeds the standard.

Description

Technical Field

[0001] The embodiments of the present invention relate to sheath circulating current monitoring and suppression technology, and in particular to a cable sheath circulating current online monitoring and suppression integrated system. Background Art

[0002] With the rapid development of cities, the demands placed on urban power grids are increasing. Power cables, due to their advantages such as stable power transmission and high power supply reliability, have been widely used in urban power grids. In actual power grids, most cables are single-core structures, such as high-voltage cables. According to the law of electromagnetic induction, when alternating current passes through a cable, an alternating magnetic field is inevitably generated. When this alternating magnetic field intersects with the cable's metal sheath, an induced voltage is generated on the sheath. If a three-phase metal sheath forms a loop with the earth, a ground loop current will form on the sheath. Excessive sheath loop current can cause the cable to overheat, reduce the current carrying capacity of the core, and in severe cases, cause the outer sheath to break down, affecting the safe and stable operation of the cable.

[0003] Although the cross-connected grounding method of the metal sheath can reduce the sheath circulating current to a certain extent, due to the variable cable laying methods and uneven segmentation, it is difficult to avoid the sheath circulating current exceeding the preset proportion of the load current. Therefore, monitoring and suppressing the cable sheath circulating current is of great practical significance.

[0004] Currently, research on sheath circulating current suppression has focused on reducing the circulating current by inserting resistors or inductors in series before grounding the metal sheath. While this has achieved some success, it also carries some negative consequences. When the load current is high or a fault such as a single-phase short circuit occurs, the addition of resistors or inductors reduces the shunt coefficient of the metal sheath, increasing the metal sheath-to-ground potential and potentially generating overvoltage, posing a threat to the cable itself and personnel. For circulating current monitoring, the current method typically requires operators to visit the project site and obtain data using clamp-on ammeters. This is time-consuming and labor-intensive. While there are devices for online monitoring of sheath circulating current, these devices only provide online monitoring and cannot effectively suppress excessive sheath circulating currents. Summary of the Invention

[0005] The present invention provides a cable sheath circulating current online monitoring and suppression integrated system, so as to improve the safety of the system, facilitate monitoring, and effectively suppress the sheath circulating current in a timely manner when the sheath circulating current exceeds the standard.

[0006] The embodiment of the present invention provides a cable sheath circulating current online monitoring and suppression integrated system, the cable sheath circulating current online monitoring and suppression integrated system includes a collection module, a main control module, and an automatic switching module;

[0007] The acquisition module includes a sheath current acquisition unit and a load current acquisition unit. The sheath current acquisition unit is installed on the sheath terminal grounding wire to detect the sheath circulating current; the load current acquisition unit is installed on the cable body to detect the load current.

[0008] The main control module is electrically connected to the sheath current acquisition unit and the load current acquisition unit, and is used to respectively acquire the sheath circulating current and the load current;

[0009] The automatic switching module includes a current suppression unit and a switch unit, and the main control module is electrically connected to the switch unit. The main control module is used to send an input signal to the switch unit when the sheath circulating current is greater than a preset proportion of the load current and the load current is lower than a preset current limit. The switch unit is used to control the current suppression unit to be connected between the sheath terminal and the ground when receiving the input signal; the main control module is used to send a cut-off signal to the switch unit when the load current is greater than the preset current limit. The switch unit is used to control the current suppression unit to be disconnected when receiving the cut-off signal, so that the sheath terminal is grounded without passing through the current suppression unit.

[0010] In an optional embodiment of the present invention, the automatic switching module includes an external line input terminal and an external line output terminal, the external line input terminal is used to be electrically connected to the sheath terminal, and the external line output terminal is used to be electrically connected to the ground;

[0011] The switch unit includes a bypass switch and an impedance switch;

[0012] The bypass switch is connected in series between the external line inlet and the external line outlet;

[0013] The impedance switch is connected in series with the current suppression unit, and the impedance switch and the current suppression unit are connected in parallel with the bypass switch as a whole;

[0014] The bypass switch is configured to be opened upon receiving the enable signal and closed upon receiving the disable signal, and the impedance switch is configured to be closed upon receiving the enable signal and open upon receiving the disable signal.

[0015] In an optional embodiment of the present invention, the current suppression unit includes a resistor and an inductor connected in series.

[0016] In an optional embodiment of the present invention, the cable sheath circulating current online monitoring and suppression integrated system further includes a current processing circuit, the number of the current processing circuits is two, and the two current processing circuits each include an operational amplifier circuit and an analog-to-digital conversion circuit;

[0017] The output end of the operational amplifier circuit is electrically connected to the input end of the analog-to-digital conversion circuit, and the output end of the analog-to-digital conversion circuit is electrically connected to the main control module;

[0018] An input end of the operational amplifier circuit of one current processing circuit is electrically connected to the sheath current acquisition unit, and an input end of the operational amplifier circuit of another current processing circuit is electrically connected to the load current acquisition unit.

[0019] In an optional embodiment of the present invention, the sheath current acquisition unit and / or the load current acquisition unit includes a measuring current transformer.

[0020] In an optional embodiment of the present invention, the cable sheath circulating current online monitoring and suppression integrated system further includes a power supply module, which is electrically connected to the main control module and is used to supply power to the main control module.

[0021] In an optional embodiment of the present invention, the power supply module includes an inductive power supply module, an output end of the inductive power supply module is electrically connected to the main control module, and the inductive power supply module is used to draw power from the cable body to supply power to the main control module.

[0022] In an optional embodiment of the present invention, the power supply module also includes a battery, the output end of the battery is electrically connected to the main control module, and the main control module is used to switch to the battery for power supply when the output of the inductive power supply module is abnormal, and to switch to the inductive power supply module for power supply when the output of the inductive power supply module is restored.

[0023] In an optional embodiment of the present invention, the inductive power extraction module includes an energy extraction current transformer and a rectifier unit, and the energy extraction current transformer is installed on the cable body and is used to extract the alternating current in the cable body;

[0024] The input end of the rectifier unit is electrically connected to the energy-taking current transformer, and the output end of the rectifier unit is electrically connected to the main control module. The rectifier unit is used to rectify the alternating current taken out by the energy-taking current transformer into direct current to power the main control module.

[0025] In an optional embodiment of the present invention, the cable sheath circulating current online monitoring and suppression integrated system further includes a protection module, the secondary side of the energy-taking current transformer and the rectifier unit both have a positive output terminal and a negative output terminal; the protection module includes at least one of the following:

[0026] a bidirectional TVS diode, one end of the bidirectional TVS diode being electrically connected to the positive output terminal of the secondary side of the energy-taking current transformer, and the other end of the bidirectional TVS diode being electrically connected to the negative output terminal of the secondary side of the energy-taking current transformer;

[0027] A unidirectional TVS diode, one end of which is electrically connected to the positive output end of the rectifier unit, and the other end of which is electrically connected to the negative output end of the rectifier unit.

[0028] In an optional embodiment of the present invention, the cable sheath circulating current online monitoring and suppression integrated system further comprises a self-test module, wherein the input end of the self-test module is electrically connected to the automatic switching module, and the output end of the self-test module is electrically connected to the main control module;

[0029] The self-check module is used to detect the operating status of the automatic switching module, and generate an abnormal signal when a fault occurs in the operating status of the automatic switching module, and send the abnormal signal to the main control module.

[0030] In an optional embodiment of the present invention, the first input end of the self-test module is electrically connected to the external line input end, the second input end of the self-test module is electrically connected to the external line output end, the third input end of the self-test module is electrically connected to the sheath current acquisition unit, and the fourth input end of the self-test module is electrically connected to the load current acquisition unit;

[0031] The self-test module is used to detect the voltage between the external input terminal and the external output terminal, and send a switch-disconnected fault signal to the main control module when the voltage between the external input terminal and the external output terminal exceeds a preset voltage range and the difference between the sheath circulating current and the zero point is less than a preset threshold value, and send a switch-closed fault signal to the main control module when the difference between the voltage between the external input terminal and the external output terminal and the zero point is less than a preset threshold value and the sheath circulating current exceeds a preset proportion of the load current.

[0032] In an optional embodiment of the present invention, the cable sheath circulating current online monitoring and suppression integrated system further comprises a communication module and a background client, wherein the main control module is electrically connected to the communication module and is configured to wirelessly communicate with the background client via the communication module;

[0033] And / or, the cable sheath circulating current online monitoring and suppression integrated system further includes a debugging module, and the main control module is electrically connected to the debugging module for debugging via the debugging module.

[0034] In an optional embodiment of the present invention, the measuring current transformer is a split-type current transformer.

[0035] The present invention is capable of respectively collecting the sheath circulating current and the load current by setting up a sheath current acquisition unit and the load current acquisition unit. The main control module compares and analyzes the sheath circulating current and the load current, and sends an input signal to the switch unit when the sheath circulating current is greater than a preset ratio of the load current and the load current is lower than a preset current limit. When the switch unit receives the input signal, it controls the current suppression unit to be connected between the sheath terminal and the ground, thereby effectively reducing the sheath circulating current and effectively suppressing the sheath circulating current to meet the operating requirements. When the load current is greater than the preset current limit, the main control module automatically sends a cut-off signal to the switch unit of the automatic switching module, so that the sheath terminal is not grounded through the current suppression unit, effectively avoiding overvoltage in the sheath that endangers personal safety and cable insulation. Therefore, the safety of the system is improved, monitoring is more convenient, and at the same time, when the sheath circulating current exceeds the standard, it can be effectively suppressed in a timely manner. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 A schematic structural diagram of a cable sheath circulating current online monitoring and suppression integrated system provided by an embodiment of the present invention;

[0037] Figure 2 A schematic diagram of the connection structure of a cable sheath circulating current online monitoring and suppression integrated system, a cable body, and a sheath provided by an embodiment of the present invention;

[0038] Figure 3 This is a schematic diagram of the connection between an automatic switching module and a main control module provided by an embodiment of the present invention;

[0039] Figure 4 1 is a schematic structural diagram of another integrated system for online monitoring and suppression of cable sheath circulating current provided by an embodiment of the present invention;

[0040] Figure 5 This is a connection diagram of an inductive power supply module and a protection module provided by an embodiment of the present invention.

[0041] Among them: 1. Acquisition module; 11. Sheath current acquisition unit; 12. Load current acquisition unit; 2. Main control module; 3. Automatic switching module; 31. Current suppression unit; 311. Resistor; 312. Inductor; 32. Switch unit; 321. Bypass switch; 322. Impedance switch; 33. External input terminal; 34. External output terminal; 4. Current processing circuit; 41. Operational amplifier circuit; 42. Analog-to-digital conversion circuit; 5. Power supply module; 51. Inductive power module; 511. Energy current transformer; 512. Rectifier unit; 52. Battery; 6. Protection module; 61. Bidirectional TVS diode; 62. Unidirectional TVS diode; 7. Self-test module; 8. Communication module; 9. Backend client; 10. Debugging module; 20. Sheath terminal grounding wire; 30. Sheath; 40. Cable body. DETAILED DESCRIPTION

[0042] The present invention will be further described in detail below with reference to the accompanying drawings and examples. It will be understood that the specific embodiments described herein are intended only to illustrate the present invention and are not intended to limit the present invention. It should also be noted that, for ease of description, the accompanying drawings only illustrate portions relevant to the present invention, not all structures.

[0043] Figure 1 A schematic diagram of the structure of a cable sheath circulating current online monitoring and suppression integrated system provided by an embodiment of the present invention. Figure 2 A schematic diagram of the connection structure of a cable sheath circulating current online monitoring and suppression integrated system and a cable body and sheath provided by an embodiment of the present invention, such as Figure 1 As shown, the cable sheath circulating current online monitoring and suppression integrated system includes an acquisition module 1, a main control module 2, and an automatic switching module 3.

[0044] The acquisition module 1 includes a sheath current acquisition unit 11 and a load current acquisition unit 12. Figure 2 As shown, the sheath current acquisition unit 11 is installed on the sheath terminal grounding wire 20 for detecting the sheath circulating current; the load current acquisition unit 12 is installed on the cable body 40 for detecting the load current.

[0045] The main control module 2 is electrically connected to the sheath current acquisition unit 11 and the load current acquisition unit 12 for respectively acquiring the sheath circulating current and the load current.

[0046] like Figure 1 As shown, the automatic switching module 3 includes a current suppression unit 31 and a switch unit 32, and the main control module 2 and the switch unit 32 are electrically connected. The main control module 2 is used to send an input signal to the switch unit 32 when the sheath circulating current is greater than a preset proportion of the load current and the load current is lower than a preset current limit. The switch unit 32 is used to control the current suppression unit 31 to be connected between the terminal of the sheath 30 and the ground when receiving the input signal; the main control module 2 is used to send a cut-off signal to the switch unit 32 when the load current is greater than the preset current limit. The switch unit 32 is used to control the current suppression unit 31 to be disconnected when receiving the cut-off signal, so that the terminal of the sheath 30 is grounded without passing through the current suppression unit 31.

[0047] The sheath current acquisition unit 11 refers to a component capable of acquiring sheath circulating current, and the load current acquisition unit 12 refers to a component capable of acquiring load current.

[0048] The current suppression unit 31 is a component that suppresses the current circulating in the sheath to meet operating requirements. Disconnection of the current suppression unit 31 means that no current flows through the branch where the current suppression unit 31 is located. The switch unit 32 is a component with a switching function that can control the connection of the current suppression unit 31 between the terminal of the sheath 30 and the ground, and can also control the disconnection of the current suppression unit 31.

[0049] When the sheath circulating current exceeds a preset ratio of the load current and the load current is lower than a preset current limit, indicating that the sheath circulating current is too large, the main control module 2 automatically sends an on signal to the switch unit 32 of the automatic switching module 3, thereby enabling the current suppression unit 31 to be connected between the terminal of the sheath 30 and the ground, thereby effectively reducing the sheath circulating current. When the load current exceeds the preset current limit, to prevent overvoltage in the sheath 30 from endangering personal safety and cable insulation, the main control module 2 automatically sends a cut-off signal to the switch unit 32 of the automatic switching module 3, thereby grounding the terminal of the sheath 30 without passing through the current suppression unit 31, effectively preventing overvoltage in the sheath 30.

[0050] The above scheme, by providing a sheath current acquisition unit 11 and a load current acquisition unit 12, can respectively collect the sheath circulating current and the load current. The main control module 2 compares and analyzes the sheath circulating current and the load current. When the sheath circulating current is greater than a preset ratio of the load current and the load current is lower than a preset current limit, it sends an input signal to the switch unit 32. Upon receiving the input signal, the switch unit 32 controls the current suppression unit 31 to connect between the terminal of the sheath 30 and the ground, thereby effectively reducing the sheath circulating current and effectively suppressing the sheath circulating current to meet the operating requirements. When the load current is greater than the preset current limit, the main control module 2 automatically sends a cut-off signal to the switch unit 32 of the automatic switching module 3, so that the terminal of the sheath 30 is not grounded through the current suppression unit 31, effectively avoiding overvoltage in the sheath 30 that endangers personal safety and cable insulation. Therefore, the safety of the system is improved, monitoring is more convenient, and when the sheath circulating current exceeds the standard, it can be effectively suppressed in a timely manner.

[0051] In an optional embodiment of the present invention, Figure 3 As shown, the automatic switching module 3 includes an external line input terminal 33 and an external line output terminal 34 . The external line input terminal 33 is used to be electrically connected to the terminal of the sheath 30 , and the external line output terminal 34 is used to be electrically connected to the ground.

[0052] The switch unit 32 includes a bypass switch 321 and an impedance switch 322 .

[0053] The bypass switch 321 is connected in series between the external line input terminal 33 and the external line output terminal 34 .

[0054] The impedance switch 322 is connected in series with the current suppression unit 31 , and the impedance switch 322 and the current suppression unit 31 are connected in parallel with the bypass switch 321 as a whole.

[0055] The bypass switch 321 is configured to be opened upon receiving an on signal and closed upon receiving a off signal, and the impedance switch 322 is configured to be closed upon receiving an on signal and opened upon receiving a off signal.

[0056] Among them, when the main control module 2 sends an input signal, the bypass switch 321 is disconnected and the impedance switch 322 is closed. At this time, the terminal of the sheath 30 will be connected to the ground through the external input terminal 33, then through the current suppression unit 31, and finally through the external output terminal 34. At this time, the current suppression unit 31 can effectively reduce the sheath circulation current and effectively suppress the sheath circulation current to meet the operating requirements. When the main control module 2 sends a cut-off signal, the bypass switch 321 is closed and the impedance switch 322 is disconnected. Therefore, at this time, the terminal of the sheath 30 will be connected to the ground through the external input terminal 33 and the external output terminal 34, effectively avoiding overvoltage in the sheath 30 that endangers personal safety and cable insulation. Therefore, the safety of the system is improved, monitoring is more convenient, and when the sheath circulation current exceeds the standard, it can be effectively suppressed in a timely manner.

[0057] Exemplarily, the current suppression unit 31 includes a resistor 311 and an inductor 312 connected in series.

[0058] Among them, connecting the resistor 311 and the inductor 312 to the circuit can effectively suppress the current, thereby effectively suppressing the sheath circulating current to meet the operation requirements.

[0059] In an optional embodiment of the present invention, the sheath current acquisition unit 11 and / or the load current acquisition unit 12 includes a measuring current transformer.

[0060] A current transformer is an instrument that converts a large primary current into a smaller secondary current based on the principle of electromagnetic induction. A current transformer consists of a closed iron core and windings. A measuring current transformer is a current transformer capable of measuring current. By including a measuring current transformer in the sheath current acquisition unit 11 and / or the load current acquisition unit 12, sheath circulating current and load current can be easily acquired.

[0061] Specifically, the measuring current transformer is a split-type current transformer.

[0062] The split-type current transformer is designed to snap directly onto the cable during use, with three elastic rubber rings supporting the cable and forming an integral part. The split-type current transformer's core is made of high-quality silicon steel sheets, and the secondary conductors are evenly wound around the core. The split-type current transformer can be installed without cutting the cable, making it easy to install and replace.

[0063] In an optional embodiment of the present invention, Figure 4As shown, the cable sheath circulating current online monitoring and suppression integrated system further includes a current processing circuit 4 . There are two current processing circuits 4 , and both current processing circuits 4 include an operational amplifier circuit 41 and an analog-to-digital conversion circuit 42 .

[0064] The output end of the operational amplifier circuit 41 is electrically connected to the input end of the analog-to-digital conversion circuit 42 , and the output end of the analog-to-digital conversion circuit 42 is electrically connected to the main control module 2 .

[0065] An input end of the operational amplifier circuit 41 of one current processing circuit 4 is electrically connected to the sheath current acquisition unit 11 , and an input end of the operational amplifier circuit 41 of another current processing circuit 4 is electrically connected to the load current acquisition unit 12 .

[0066] The operational amplifier circuit 41 is a circuit capable of amplifying input signals, and the analog-to-digital conversion circuit 42 is a circuit capable of converting analog signals into digital signals. Since the currents collected by the sheath current acquisition unit 11 and the load current acquisition unit 12 are relatively small, they are amplified by the operational amplifier circuit 41 to facilitate subsequent processing. Since the collected sheath circulating current and load current are analog signals, they can be easily converted into digital signals by the analog conversion circuit for processing by the main control module 2.

[0067] In an optional embodiment of the present invention, the cable sheath circulating current online monitoring and suppression integrated system further includes a power supply module 5 , which is electrically connected to the main control module 2 and is used to supply power to the main control module 2 .

[0068] The power module 5 refers to a module capable of supplying power. By providing the power module 5 , the main control module 2 is more convenient to use.

[0069] Based on the above embodiment, the power supply module 5 includes an inductive power supply module 51 , the output end of which is electrically connected to the main control module 2 , and the inductive power supply module 51 is used to draw power from the cable body 40 to supply power to the main control module 2 .

[0070] Among them, the inductive power supply module 51 refers to a circuit that can draw power from the cable body 40. Through the inductive power supply module 51, there is no need for an external power supply. The electric energy transmitted in the cable can be directly taken out to power the main control module 2, which is more convenient.

[0071] Exemplarily, the power supply module 5 also includes a battery 52, the output end of the battery 52 is electrically connected to the main control module 2, and the main control module 2 is used to switch to the battery 52 for power supply when the output of the inductive power supply module 51 is abnormal, and to switch to the inductive power supply module 51 for power supply when the output of the inductive power supply module 51 is restored.

[0072] An output abnormality in the inductive power module 51 means that the signal outputted from the output terminal of the inductive power module 51 does not match the preset signal or is absent. A recovery in the output of the inductive power module 51 means that the signal outputted from the output terminal of the inductive power module 51 matches the preset signal. This approach enables hybrid power supply: when the inductive power module 51 fails, it automatically switches to battery 52 power supply mode. After the inductive power module 51 recovers from the failure, it switches back to inductive power supply mode, ensuring uninterrupted power supply.

[0073] In addition, in a specific embodiment, the battery 52 may be a lithium battery 52. ​​Preferably, the lithium battery 52 may also be a replaceable battery 52.

[0074] Specifically, the output end of the inductive power supply module 51 is electrically connected to the battery 52 for supplying power to the battery 52 .

[0075] For example, the inductive power module 51 includes an energy current transformer 511 and a rectifier unit 512. Figure 1 As shown, the energy extraction current transformer 511 is installed on the cable body 40 and is used to extract the alternating current in the cable body 40.

[0076] The input end of the rectifier unit 512 is electrically connected to the energy-taking current transformer 511 , and the output end of the rectifier unit 512 is electrically connected to the main control module 2 . The rectifier unit 512 is used to rectify the AC power taken out by the energy-taking current transformer 511 into DC power to power the main control module 2 .

[0077] The energy extraction current transformer 511 is a current transformer capable of extracting electrical energy from the cable body 40, and the rectifier unit 512 is a circuit capable of rectifying AC power into DC power. Since the cable body 40 typically operates on AC power, while the operating voltage of the main control module 2 is typically DC power, the energy extraction current transformer 511 and the rectifier unit 512 facilitate the extraction of electrical energy from the cable body 40 to power the main control module 2.

[0078] In an optional embodiment of the present invention, Figure 5 As shown, the cable sheath circulating current online monitoring and suppression integrated system further includes a protection module 6. The secondary side of the energy-taking current transformer 511 and the rectifier unit 512 both have a positive output terminal and a negative output terminal. The protection module 6 includes at least one of the following:

[0079] A bidirectional TVS diode 61 , one end of the bidirectional TVS diode 61 is electrically connected to the positive output end of the secondary side of the energy extraction current transformer 511 , and the other end of the bidirectional TVS diode 61 is electrically connected to the negative output end of the secondary side of the energy extraction current transformer 511 .

[0080] A unidirectional TVS diode 62 , one end of which is electrically connected to the positive output end of the rectifier unit 512 , and the other end of which is electrically connected to the negative output end of the rectifier unit 512 .

[0081] Among them, by setting up a bidirectional TVS diode 61, it is possible to prevent the induced voltage on the secondary side of the energy-taking current transformer 511 from being too high, and limit the AC voltage on the secondary side of the energy-taking current transformer 511 to a certain range; the unidirectional TVS diode 62 can prevent the rectifier circuit from outputting an excessively high DC voltage, and limit the rectifier output voltage to a certain range, effectively preventing the cable body 40 from being struck by lightning, and preventing the overvoltage and overcurrent generated by the inductive power-taking circuit from harming the subsequent circuit.

[0082] In an optional embodiment of the present invention, Figure 4 As shown, the cable sheath circulating current online monitoring and suppression integrated system further includes a self-test module 7 , the input end of the self-test module 7 is electrically connected to the automatic switching module 3 , and the output end of the self-test module 7 is electrically connected to the main control module 2 .

[0083] The self-check module 7 is used to detect the operating status of the automatic switching module 3 , and generate an abnormal signal when a fault occurs in the operating status of the automatic switching module 3 , and send the abnormal signal to the main control module 2 .

[0084] Among them, the self-test module 7 refers to a circuit that can detect whether the operating status of the automatic switching module 3 is normal. By setting the self-test module 7 to detect the operating status of the automatic switching module 3, and generating an abnormal signal when a fault occurs in the operating status of the automatic switching module 3, and sending the abnormal signal to the main control module 2, the main control module 2 can promptly know the abnormal situation of the automatic switching module 3.

[0085] Based on the above embodiment, the first input end of the self-test module 7 is electrically connected to the external input terminal 33, the second input end of the self-test module 7 is electrically connected to the external output terminal 34, the third input end of the self-test module 7 is electrically connected to the sheath current acquisition unit 11, and the fourth input end of the self-test module 7 is electrically connected to the load current acquisition unit 12.

[0086] The self-test module 7 is used to detect the voltage between the external input terminal 33 and the external output terminal 34, and send a switch-off fault signal to the main control module 2 when the voltage between the external input terminal 33 and the external output terminal 34 exceeds a preset voltage range and the difference between the sheath circulating current and the zero point is less than a preset threshold value, and send a switch-off fault signal to the main control module 2 when the difference between the voltage between the external input terminal 33 and the external output terminal 34 and the zero point is less than a preset threshold value and the sheath circulating current exceeds a preset proportion of the load current.

[0087] Among them, under normal circumstances, the bypass switch 321 and the impedance switch 322 are one open and one closed. When an abnormality occurs, the bypass switch 321 and the impedance switch 322 may be closed or disconnected at the same time. When the two switches are closed at the same time, the current limiting resistor 311 will not work. When the two switches are disconnected at the same time, the terminal of the sheath 30 will not be reliably grounded (this situation will cause the induced voltage to be too large).

[0088] Therefore, by providing a self-test module 7 to detect the voltage between the external input terminal 33 and the external output terminal 34, and simultaneously obtain the sheath circulating current and load current, it is possible to determine whether the automatic switching module 3 is faulty based on the voltage between the external input terminal 33 and the external output terminal 34 and the changes in the sheath circulating current before and after the switch is actuated. When it is detected that the voltage between the external input terminal 33 and the external output terminal 34 is abnormal and the sheath circulating current is almost zero, it is determined that the bypass switch 321 and the impedance switch 322 are both open at the same time, and a simultaneous switch-off fault signal is transmitted to the main control module 2. When it is detected that the voltage between the external input terminal 33 and the external output terminal 34 is almost zero and the sheath circulating current is abnormal, it is determined that the bypass switch 321 and the impedance switch 322 are both closed at the same time, and a simultaneous switch-on fault signal is transmitted to the main control module 2. Therefore, through the above method, the self-test module 7 can conveniently detect whether the automatic switching module 3 is operating normally and promptly inform the main control module 2 of any abnormal conditions in the automatic switching module 3.

[0089] In an optional embodiment of the present invention, Figure 4 As shown, the cable sheath circulating current online monitoring and suppression integrated system also includes a communication module 8 and a background client 9. The main control module 2 is electrically connected to the communication module 8 and is used for wireless communication with the background client 9 through the communication module 8.

[0090] The communication module 8 is a module that enables wireless communication between the main control module 2 and the backend client 9. The communication module 8 can utilize APN dedicated wireless communication and supports various wireless networks, including GPRS, 3G, 4G, and 5G. The backend client 9 has data recording and fault analysis capabilities. The main control module 2 can wirelessly transmit the acquired sheath circulating current and load current, as well as fault conditions and the operating status of the automatic switching module 3, to the backend client 9 for storage. The backend client 9 can then generate daily, weekly, monthly, and annual reports on circulating current, and can export the operating records of the automatic switching module 3 for event analysis by operators.

[0091] In an optional embodiment of the present invention, the cable sheath circulating current online monitoring and suppression integrated system further includes a debugging module 10 , and the main control module 2 is electrically connected to the debugging module 10 for debugging via the debugging module 10 .

[0092] The debugging module 10 has a debugging interface, and the debugging module 10 can debug the main control module 2, change the built-in program, and has a remote debugging and upgrading function.

[0093] In a specific embodiment, the main control module 2, automatic switching module 3, communication module 8, protection module 6, debugging module 10, self-test module 7, power module 5, and current processing circuit 4 form an intelligent terminal host. The intelligent terminal host has a housing and can be installed in the terminal grounding box of the sheath 30. After receiving the sheath circulating current and load current collected by the sheath current acquisition unit 11 and the load current acquisition unit 12, the intelligent terminal host processes and analyzes the data and makes judgments based on built-in logic to achieve online monitoring and automatic suppression of the sheath 30 grounding loop current. The intelligent terminal host wirelessly communicates with the background client 9, which has event recording and fault analysis functions, allowing for convenient monitoring of the cable, online monitoring, and suppression of the intelligent terminal host's operating status.

[0094] In addition, the intelligent terminal host may also have a metal casing, which is well grounded to prevent the intelligent terminal host body from being struck by lightning.

[0095] Note that the above are only preferred embodiments of the present invention and the technical principles employed. Those skilled in the art will appreciate that the present invention is not limited to the specific embodiments herein, and that various obvious changes, readjustments, and substitutions are possible for those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments and may include many other equivalent embodiments without departing from the scope of the present invention. The scope of the present invention is determined by the scope of the appended claims.

Claims

1. A cable sheath circulating current online monitoring and suppression integrated system, characterized in that: It includes an acquisition module (1), a main control module (2), and an automatic switching module (3); The acquisition module (1) comprises a sheath current acquisition unit (11) and a load current acquisition unit (12); the sheath current acquisition unit (11) is mounted on the sheath terminal grounding wire (20) and is used to detect sheath circulating current; the load current acquisition unit (12) is mounted on the cable body (40) and is used to detect load current; The main control module (2) is electrically connected to the sheath current acquisition unit (11) and the load current acquisition unit (12), and is used to respectively acquire the sheath circulating current and the load current; The automatic switching module (3) comprises a current suppression unit (31) and a switch unit (32); the main control module (2) and the switch unit (32) are electrically connected; the main control module (2) is used to send an input signal to the switch unit (32) when the sheath circulating current is greater than a preset proportion of the load current and the load current is lower than a preset current limit; the switch unit (32) is used to control the current suppression unit (31) to be connected between the terminal of the sheath (30) and the ground when receiving the input signal; the main control module (2) is used to send a cut-off signal to the switch unit (32) when the load current is greater than the preset current limit; the switch unit (32) is used to control the current suppression unit (31) to be disconnected when receiving the cut-off signal, so that the terminal of the sheath (30) is grounded without passing through the current suppression unit (31).

2. The cable sheath circulating current online monitoring and suppression integrated system according to claim 1 is characterized in that: The automatic switching module (3) comprises an external line inlet (33) and an external line outlet (34), wherein the external line inlet (33) is used to be electrically connected to the terminal of the sheath (30), and the external line outlet (34) is used to be electrically connected to the ground; The switch unit (32) includes a bypass switch (321) and an impedance switch (322); The bypass switch (321) is connected in series between the external line inlet (33) and the external line outlet (34); The impedance switch (322) is connected in series with the current suppression unit (31), and the impedance switch (322) and the current suppression unit (31) are connected in parallel with the bypass switch (321) as a whole; The bypass switch (321) is used to be opened when receiving the input signal and closed when receiving the cut-off signal, and the impedance switch (322) is used to be closed when receiving the input signal and opened when receiving the cut-off signal.

3. The cable sheath circulating current online monitoring and suppression integrated system according to claim 2 is characterized in that: The current suppression unit (31) includes a resistor (311) and an inductor (312) connected in series.

4. The cable sheath circulating current online monitoring and suppression integrated system according to any one of claims 1 to 3, characterized in that: The cable sheath circulating current online monitoring and suppression integrated system further comprises a current processing circuit (4), wherein the number of the current processing circuits (4) is two, and the two current processing circuits (4) each comprise an operational amplifier circuit (41) and an analog-to-digital conversion circuit (42); The output end of the operational amplifier circuit (41) is electrically connected to the input end of the analog-to-digital conversion circuit (42), and the output end of the analog-to-digital conversion circuit (42) is electrically connected to the main control module (2); The input end of the operational amplifier circuit (41) of one current processing circuit (4) is electrically connected to the sheath current acquisition unit (11), and the input end of the operational amplifier circuit (41) of another current processing circuit (4) is electrically connected to the load current acquisition unit (12).

5. The cable sheath circulating current online monitoring and suppression integrated system according to claim 4 is characterized in that: The sheath current acquisition unit (11) and / or the load current acquisition unit (12) include a measuring current transformer.

6. The cable sheath circulating current online monitoring and suppression integrated system according to claim 1 is characterized in that: The cable sheath circulating current online monitoring and suppression integrated system further comprises a power supply module (5), wherein the power supply module (5) is electrically connected to the main control module (2) and is used to supply power to the main control module (2).

7. The cable sheath circulating current online monitoring and suppression integrated system according to claim 6 is characterized in that: The power supply module (5) comprises an inductive power supply module (51), the output end of the inductive power supply module (51) is electrically connected to the main control module (2), and the inductive power supply module (51) is used to obtain power from the cable body (40) to supply power to the main control module (2).

8. The cable sheath circulating current online monitoring and suppression integrated system according to claim 7 is characterized in that: The power supply module (5) further comprises a battery (52), the output end of the battery (52) being electrically connected to the main control module (2), and the main control module (2) being used to switch to the battery (52) for power supply when the output of the inductive power module (51) is abnormal, and to switch to the inductive power module (51) for power supply when the output of the inductive power module (51) is restored.

9. The cable sheath circulating current online monitoring and suppression integrated system according to claim 7, characterized in that: The inductive power extraction module (51) includes an energy extraction current transformer (511) and a rectifier unit (512); the energy extraction current transformer (511) is installed on the cable body (40) and is used to extract the alternating current in the cable body (40); The input end of the rectifier unit (512) is electrically connected to the energy-taking current transformer (511), and the output end of the rectifier unit (512) is electrically connected to the main control module (2). The rectifier unit (512) is used to rectify the alternating current taken out by the energy-taking current transformer (511) into direct current to supply power to the main control module (2).

10. The cable sheath circulating current online monitoring and suppression integrated system according to claim 9, characterized in that: The cable sheath circulating current online monitoring and suppression integrated system further comprises a protection module (6), wherein the secondary side of the energy-taking current transformer (511) and the rectifier unit (512) both have a positive output terminal and a negative output terminal; and the protection module (6) comprises at least one of the following: a bidirectional TVS diode (61), one end of the bidirectional TVS diode (61) being electrically connected to the positive output end of the secondary side of the energy extraction current transformer (511), and the other end of the bidirectional TVS diode (61) being electrically connected to the negative output end of the secondary side of the energy extraction current transformer (511); A unidirectional TVS diode (62), one end of the unidirectional TVS diode (62) is electrically connected to the positive output end of the rectifier unit (512), and the other end of the unidirectional TVS diode (62) is electrically connected to the negative output end of the rectifier unit (512).

11. The cable sheath circulating current online monitoring and suppression integrated system according to claim 2, characterized in that: The cable sheath circulating current online monitoring and suppression integrated system further comprises a self-test module (7), the input end of the self-test module (7) is electrically connected to the automatic switching module (3), and the output end of the self-test module (7) is electrically connected to the main control module (2); The self-check module (7) is used to detect the operating state of the automatic switching module (3), and to generate an abnormal signal when a fault occurs in the operating state of the automatic switching module (3), and to send the abnormal signal to the main control module (2).

12. The cable sheath circulating current online monitoring and suppression integrated system according to claim 11, characterized in that: The first input end of the self-test module (7) is electrically connected to the external line-in terminal (33), the second input end of the self-test module (7) is electrically connected to the external line-out terminal (34), the third input end of the self-test module (7) is electrically connected to the sheath current acquisition unit (11), and the fourth input end of the self-test module (7) is electrically connected to the load current acquisition unit (12); The self-check module (7) is used to detect the voltage between the external incoming terminal (33) and the external outgoing terminal (34), and to send a switch-off fault signal to the main control module (2) when the voltage between the external incoming terminal (33) and the external outgoing terminal (34) exceeds a preset voltage range and the difference between the sheath circulating current and the zero point is less than a preset threshold value, and to send a switch-on fault signal to the main control module (2) when the difference between the voltage between the external incoming terminal (33) and the external outgoing terminal (34) and the zero point is less than a preset threshold value and the sheath circulating current exceeds a preset proportion of the load current.

13. The cable sheath circulating current online monitoring and suppression integrated system according to claim 1, characterized in that: The cable sheath circulation online monitoring and suppression integrated system further comprises a communication module (8) and a background client (9), wherein the main control module (2) is electrically connected to the communication module (8) and is used for wireless communication with the background client (9) via the communication module (8); And / or, the cable sheath circulating current online monitoring and suppression integrated system further comprises a debugging module (10), and the main control module (2) is electrically connected to the debugging module (10) for debugging via the debugging module (10).

14. The cable sheath circulating current online monitoring and suppression integrated system according to claim 5, characterized in that: The measuring current transformer is a split-type current transformer.

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