A leakage detection system and method for a power supply line

Abstract

This invention discloses a leakage current detection system and method for power supply lines. The leakage current detection system includes an air switch; a three-phase four-wire leakage current switch, connected to the input terminal of the air switch and the mains power supply respectively; a controller, connected to the output terminal of the air switch and several groups of controlled devices, each group of controlled devices including several controlled devices; the controller includes a main control module, a three-phase four-wire input interface, a three-phase power parameter acquisition module, a three-phase circuit control module, a three-phase current detection module, a circuit leakage current detection module, a neutral line circuit control module, a neutral line current detection module, and a communication module; it can push fault information to maintenance personnel immediately after the controlled devices are damaged or have leakage faults; when a leakage fault occurs, the system can push the leakage fault point to the maintenance personnel for reference immediately; fault diagnosis and intelligent inspection save a lot of resources for the maintenance of controlled devices, reduce the probability of fault occurrence, shorten the fault repair time, and bring more intuitive economic and social benefits.

Description

Technical Field

[0001] This invention relates to the field of leakage current detection technology, and in particular to a leakage current detection system and method for power supply lines. Background Technology

[0002] In rural and urban areas, common mainline power supply systems are widely deployed, such as street lighting systems. These systems often have aging lines, making them prone to leakage accidents during rainy weather. Because older power lines typically use a three-phase simultaneous installation, there are no clear requirements on which phase each controlled device uses for power. Therefore, when a leakage occurs, it is often necessary to disconnect the power supply to all controlled devices in that section to troubleshoot the problem. Even if leakage detection equipment is installed on the main road, it can only detect a problem in one power line, making it extremely difficult to pinpoint the exact problem. Construction workers often need to manually disconnect single-phase circuit breakers at the inspection ports of each controlled device, repeatedly disconnecting the circuit using a process of elimination, and sometimes even digging up and burying the lines multiple times to solve the problem. This results in lengthy troubleshooting and repair times after a leakage accident, and also affects the lighting of the controlled devices. Therefore, there is an urgent need for a leakage detection system and method for power supply lines to solve these problems. Summary of the Invention

[0003] The present invention aims to at least solve one of the technical problems existing in the prior art. To this end, the present invention proposes a leakage current detection system and method for power supply lines.

[0004] One embodiment of the present invention provides a technical solution to solve its technical problem: a leakage current detection system for power supply lines, comprising:

[0005] air switch;

[0006] A three-phase four-wire residual current circuit breaker is connected to the input terminal of an air circuit breaker and the mains power supply, respectively.

[0007] The controller is connected to the output terminal of the air switch and several groups of controlled devices, and each group of controlled devices includes several controlled devices;

[0008] The controller includes a main control module, a three-phase four-wire input interface, a three-phase electrical parameter acquisition module, a three-phase circuit control module, a three-phase current detection module, a circuit leakage current detection module, a neutral line circuit control module, a neutral line current detection module, and a communication module. The three-phase four-wire input interface is connected to the main control module via the three-phase electrical parameter acquisition module, the three-phase circuit control module, and the three-phase current detection module, and is also connected to the main control module via the circuit leakage current detection module, the neutral line circuit control module, and the neutral line current detection module. The main control module can send the detected leakage current signal to the backend through the communication module.

[0009] Furthermore, the controller also includes a display screen, buttons, indicator lights, and / or a buzzer connected to the main control module and the communication module.

[0010] Furthermore, the controller also includes a timer switch, a latitude and longitude acquisition module, and / or an illuminance detection module, which are respectively connected to the main control module, the three-phase circuit control module, and the N-line circuit control module.

[0011] Furthermore, the controller also includes an inspection module connected to the main control module and the communication module respectively, which is used to receive inspection instructions and automatically execute inspection operations.

[0012] Furthermore, the communication module is configured as 4G, 5G, or NB wide area network.

[0013] Furthermore, the communication module is configured with Zigbee, LoRa, or 433M LAN.

[0014] A method for detecting leakage current in the power supply line of a controlled device, applied to a leakage current detection system for the power supply line of the controlled device:

[0015] ① A leakage fault has occurred; set the fault alarm for controlled device B. n A leakage current caused the three-phase four-wire leakage current detection switch at a node of a controlled device on the power supply line to trip. The following steps should be performed:

[0016] Step 1.1: The controller first disconnects the B-phase and C-phase circuits, while keeping the A-phase circuit powered on.

[0017] Step 1.2, Control B n If the residual current circuit breaker can be closed and B... n If the detected leakage current data is qualified, proceed to step 1.3; if the circuit breaker cannot be closed, proceed to step 1.5.

[0018] Step 1.3: Control B sequentially n+1 B n+2 ...B n+n If the circuit breaker can be closed, continue the inspection. If the circuit breaker cannot be closed, proceed to step 1.5.

[0019] Step 1.4: When phase A is powered, if all residual current circuit breakers at the controlled equipment nodes can be closed, the controller disconnects the phase A and phase C circuits, retains phase B for continued power supply, and repeats steps 1.2-1.3; if all residual current circuit breakers at the controlled equipment nodes can be closed when phase B is powered, the controller disconnects the phase A and phase B circuits, retains phase C for continued power supply, and repeats steps 1.2-1.3.

[0020] Step 1.5: The controller supplies power to the B-phase circuit. If the patrol detection detects B... n+x The circuit breaker cannot be closed at point B. n+x+1After tripping, the controller disconnects the power supply to phase B circuit and controls phase B. n+x If the circuit breaker can be closed, then step 1.5 is executed again, and X is increased by 1, until the circuit breaker cannot be closed. Assume that at this point, when n+x=k, B is detected. k If the circuit breaker cannot be closed at point B, then the leakage fault occurred at point B. k and B k+1 On phase A of the line;

[0021] ② No leakage fault occurred. The leakage current of the three-phase four-wire circuit measured at the node of the controlled equipment is set as IA1, IA2...IA by the node name. n IB1, IB2...IB n IC1, IC2...IC n If the maximum leakage current of the power supply line between two adjacent controlled device nodes is set to Idmax, then the following steps are performed:

[0022] Step 2.1: Read IA1, IA2...IA sequentially. n IB1, IB2...IB n IC1, IC2...IC n Calculate the leakage current difference I between two adjacent controlled device nodes. d =I k -I k+1 , if I d dmax Then the controlled device node increments by 1 sequentially until I is measured. d >I dmax If the measured node number of the controlled equipment is t at this time, the fault point occurs between the t and t+1 road segments, and proceed to step 2.2;

[0023] Step 2.2: The controller disconnects the B and C phase circuits, while keeping phase A powered on. The leakage current difference Ita between node t and t+1 of the controlled equipment is measured.

[0024] Step 2.3: The controller disconnects the A and C phase circuits, while keeping phase B powered on. The leakage current difference Itb between node t and t+1 of the controlled equipment is measured.

[0025] Step 2.4: The controller disconnects the A and B phase circuits, while retaining the C phase to continue supplying power. The leakage current difference Itc between node t and t+1 of the controlled equipment is measured.

[0026] ​Step 2.5: Compare the values ​​of Ita, Itb, and Itc. If Ita is the largest, the fault point is on the A-phase line between the controlled equipment nodes t and t+1; if Itb is the largest, the fault point is on the B-phase line between the controlled equipment nodes t and t+1; if Itc is the largest, the fault point is on the C-phase line between the controlled equipment nodes t and t+1.

[0027] The beneficial effects of this invention are:

[0028] 1. When the controlled equipment malfunctions, such as damage or leakage, the system can immediately push fault information to the maintenance personnel;

[0029] 2. In the event of a leakage fault, the system can immediately push the leakage fault point (minimum range) to the maintenance personnel for reference;

[0030] For example, the fault range is 001-002, which means the fault is between controlled device 001 and controlled device 002.

[0031] 3. The system can be set to perform regular intelligent inspections to predict the occurrence of leakage accidents in advance;

[0032] 4. Fault diagnosis and intelligent inspection save a lot of resources for the maintenance of controlled equipment, reduce the probability of failure, shorten the time for emergency repair, ensure life safety, and bring more direct economic and social benefits. Attached Figure Description

[0033] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0034] Figure 1 A typical system connection diagram for power supply lines to streetlights;

[0035] Figure 2 This is a connection diagram of a street light power supply line system according to an embodiment of the present invention;

[0036] Figure 3 This is a functional framework diagram of the controller in centralized control mode according to an embodiment of the present invention;

[0037] Figure 4 This is a functional framework diagram of the controller in single-lamp control mode according to an embodiment of the present invention. Detailed Implementation

[0038] This section will describe in detail specific embodiments of the present invention. Preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the drawings is to supplement the textual description with graphics, so that people can intuitively and vividly understand each technical feature and overall technical solution of the present invention, but they should not be construed as limiting the scope of protection of the present invention.

[0039] In the description of this invention, "multiple" means two or more; "greater than," "less than," and "exceeding" are understood to exclude the stated number; "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0040] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0041] In this invention, unless otherwise explicitly defined, the terms "setting," "installing," and "connecting" should be interpreted broadly. For example, they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to a fixed connection, a detachable connection, or an integrally formed connection; they can refer to a mechanical connection; they can refer to the internal connection of two components or the interaction between two components. Those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0042] Reference Figures 1 to 4 A leakage current detection system for power supply lines, comprising:

[0043] air switch;

[0044] A three-phase four-wire residual current circuit breaker is connected to the input terminal of an air circuit breaker and the mains power supply, respectively.

[0045] The controller is connected to the output terminal of the air switch and several groups of controlled devices, and each group of controlled devices includes several controlled devices;

[0046] The controller includes a main control module, a three-phase four-wire input interface, a three-phase electrical parameter acquisition module, a three-phase circuit control module, a three-phase current detection module, a circuit leakage current detection module, a neutral line circuit control module, a neutral line current detection module, and a communication module. The three-phase four-wire input interface is connected to the main control module via the three-phase electrical parameter acquisition module, the three-phase circuit control module, and the three-phase current detection module, and is also connected to the main control module via the circuit leakage current detection module, the neutral line circuit control module, and the neutral line current detection module. The main control module can send the detected leakage current signal to the backend through the communication module.

[0047] Preferably, the three-phase electrical parameter acquisition module includes an A-phase electrical parameter acquisition module, a B-phase electrical parameter acquisition module, and a C-phase electrical parameter acquisition module; the three-phase circuit control module includes an A-phase circuit control module, a B-phase circuit control module, and a C-phase circuit control module; and the three-phase current detection module includes an A-phase current detection module, a B-phase current detection module, and a C-phase current detection module.

[0048] The controller also includes a display screen, buttons, indicator lights, and / or a buzzer connected to the main control module and the communication module.

[0049] The controller also includes a timer switch, a latitude and longitude acquisition module, and / or an illuminance detection module, which are respectively connected to the main control module, the three-phase circuit control module, and the N-line circuit control module.

[0050] The controller also includes an inspection module that is connected to the main control module and the communication module respectively, which is used to receive inspection instructions and automatically execute inspection operations.

[0051] The communication module is set to 4G, 5G or NB wide area network.

[0052] The communication module is set to Zigbee, LoRa, or 433M LAN.

[0053] Reference Figure 3 The diagram below illustrates the functional framework of a controller in centralized control mode according to an embodiment of the present invention. 1. A loop control module controls the power supply to the loop on and off. 2. A loop leakage current detection module detects leakage current in one or more loops. 3. An intelligent inspection module detects leakage faults or remotely commands equipment to perform fault inspections. It controls loop switches on different phase lines, switches different loads, and uses monitored electrical parameters and leakage data for local calculation and analysis to ultimately determine the cause and result of the fault. 4. A timer switch sets a fixed timer control strategy locally or remotely. 5. A latitude and longitude acquisition module obtains local latitude and longitude to calculate sunrise and sunset times for controlling load switches. 6. A illuminance detection module detects the illuminance of the current environment to control load switches. 7. A three-phase electrical parameter acquisition module acquires parameters such as voltage, power consumption, and phase angle for each phase line. 8. A three-phase phase current detection module detects the load current magnitude on each phase line.

[0054] Reference Figure 4The diagram below illustrates the functional framework of a controller in single-lamp control mode according to an embodiment of the present invention. 1. A three-phase four-wire leakage current detection module is used to detect leakage current in all load circuits after the leakage current switch, and to remotely control the opening and closing of the switch; 2. A timing strategy can save one or more different timing lighting schemes, allowing control of the streetlights even without a network connection; 3. A single-phase leakage current detection module is used to detect the leakage current in the load circuit; 4. A single-phase switch control module is used to control the power supply to the current in the phase circuit; 5. A single-phase current detection module is used to detect the magnitude of the current in the phase load circuit.

[0055] A method for detecting leakage current in the power supply line of a controlled device, applied to a leakage current detection system for the power supply line of the controlled device:

[0056] ① A leakage fault has occurred; set the fault alarm for controlled device B. n A leakage current caused the three-phase four-wire leakage current detection switch at a node of a controlled device on the power supply line to trip. The following steps should be performed:

[0057] Step 1.1: The controller first disconnects the B-phase and C-phase circuits, while keeping the A-phase circuit powered on.

[0058] Step 1.2, Control B n If the residual current circuit breaker can be closed and B... n If the detected leakage current data is qualified, proceed to step 1.3; if the circuit breaker cannot be closed, proceed to step 1.5.

[0059] Step 1.3: Control B sequentially n+1 B n+2 ...B n+n If the circuit breaker can be closed, continue the inspection. If the circuit breaker cannot be closed, proceed to step 1.5.

[0060] Step 1.4: When phase A is powered, if all residual current circuit breakers at the controlled equipment nodes can be closed, the controller disconnects the phase A and phase C circuits, retains phase B for continued power supply, and repeats steps 1.2-1.3; if all residual current circuit breakers at the controlled equipment nodes can be closed when phase B is powered, the controller disconnects the phase A and phase B circuits, retains phase C for continued power supply, and repeats steps 1.2-1.3.

[0061] Step 1.5: The controller supplies power to the B-phase circuit. If the patrol detection detects B... n+x The circuit breaker cannot be closed at point B. n+x+1 After tripping, the controller disconnects the power supply to phase B circuit and controls phase B. n+x If the circuit breaker can be closed, then step 1.5 is executed again, and X is increased by 1, until the circuit breaker cannot be closed. Assume that at this point, when n+x=k, B is detected. k If the circuit breaker cannot be closed at point B, then the leakage fault occurred at point B.k and B k+1 On phase A of the line.

[0062] In this invention, a street light power supply system is used as an example to illustrate the leakage current detection method. As a preferred embodiment, if a leakage current fault has occurred and the system fault alarm indicates leakage current in street light B2, causing the three-phase four-wire leakage current detection switch at a street light node on the power supply line to trip, the following steps are performed when performing leakage current detection:

[0063] Step 1.1: The controller first disconnects the B-phase and C-phase circuits, while keeping the A-phase circuit powered on.

[0064] Step 1.2: Control the leakage current switch at B2 to close. If it can be closed and the leakage current data detected at B2 is qualified, proceed to step 1.3. If it cannot be closed, proceed to step 1.5.

[0065] Step 1.3: Sequentially control B3, B4... to close. If the circuit can be closed, continue the inspection. If the circuit cannot be closed, proceed to step 1.5.

[0066] Step 1.4: When phase A is powered, if all street light node leakage circuit breakers can be closed, the controller disconnects the phase A and phase C circuits, retains phase B to continue power supply, and repeats steps 1.2-1.3; if all street light node leakage circuit breakers can be closed when phase B is powered, the controller disconnects the phase A and phase B circuits, retains phase C to continue power supply, and repeats steps 1.2-1.3.

[0067] Step 1.5: The controller supplies power to the B-phase circuit for closing. If the detection detects that B7 cannot be closed, the controller disconnects the power supply to the B-phase circuit after controlling B8 to open, and then controls B7 to close. If it can close, then step 1.5 is executed again, and the node number is incremented by 1, until it cannot be closed. Assume that at this time, B... 15 If the circuit breaker cannot be closed at point B, then the leakage fault occurred at point B. 15 and B 16 On phase A of the line.

[0068] ② No leakage fault occurred. The leakage current of the three-phase four-wire circuit measured at the node of the controlled equipment is set as IA1, IA2...IA by the node name. n IB1, IB2...IB n IC1, IC2...IC n If the maximum leakage current of the power supply line between two adjacent controlled device nodes is set to Idmax, then the following steps are performed:

[0069] Step 2.1: Read IA1, IA2...IA sequentially. n IB1, IB2...IB nIC1, IC2...IC n Calculate the leakage current difference I between two adjacent controlled device nodes. d =I k -I k+1 , if I d dmax Then the controlled device node increments by 1 sequentially until I is measured. d >I dmax If the measured node number of the controlled equipment is t at this time, the fault point occurs between the t and t+1 road segments, and proceed to step 2.2;

[0070] Step 2.2: The controller disconnects the B and C phase circuits, while keeping phase A powered on. The leakage current difference Ita between node t and t+1 of the controlled equipment is measured.

[0071] Step 2.3: The controller disconnects the A and C phase circuits, while keeping phase B powered on. The leakage current difference Itb between node t and t+1 of the controlled equipment is measured.

[0072] Step 2.4: The controller disconnects the A and B phase circuits, while retaining the C phase to continue supplying power. The leakage current difference Itc between node t and t+1 of the controlled equipment is measured.

[0073] Step 2.5: Compare the values ​​of Ita, Itb, and Itc. If Ita is the largest, the fault point is on the A-phase line between the controlled equipment nodes t and t+1; if Itb is the largest, the fault point is on the B-phase line between the controlled equipment nodes t and t+1; if Itc is the largest, the fault point is on the C-phase line between the controlled equipment nodes t and t+1.

[0074] The advantages of this invention are:

[0075] 1. When the controlled equipment malfunctions, such as damage or leakage, the system can immediately push fault information to the maintenance personnel;

[0076] 2. In the event of a leakage fault, the system can immediately push the leakage fault point (minimum range) to the maintenance personnel for reference;

[0077] For example, the fault range is 001-002, which means the fault is between controlled device 001 and controlled device 002.

[0078] 3. The system can be set to perform regular intelligent inspections to predict the occurrence of leakage accidents in advance;

[0079] 4. Fault diagnosis and intelligent inspection save a lot of resources for the maintenance of controlled equipment, reduce the probability of failure, shorten the time for emergency repair, ensure life safety, and bring more direct economic and social benefits.

[0080] ​Of course, the present invention is not limited to the above-described embodiments. Those skilled in the art can make equivalent modifications or substitutions without departing from the spirit of the present invention, and these equivalent modifications and substitutions are all included within the scope defined by the claims of this application.

Claims

1. A leakage current detection system for power supply lines, characterized in that, include: air switch; The three-phase four-wire leakage circuit breaker is connected to the input terminal of the air switch and the mains power supply, respectively. The controller is connected to the output terminal of the air switch and to several groups of controlled devices, each group of controlled devices including several controlled devices; The controller includes a main control module, a three-phase four-wire input interface, a three-phase electrical parameter acquisition module, a three-phase circuit control module, a three-phase current detection module, a circuit leakage detection module, a neutral line circuit control module, a neutral line current detection module, and a communication module. The three-phase four-wire input interface is connected to the main control module via the three-phase electrical parameter acquisition module, the three-phase circuit control module, and the three-phase current detection module, and is also connected to the main control module via the circuit leakage detection module, the neutral line circuit control module, and the neutral line current detection module. The main control module can send the detected leakage signal to the background through the communication module. The controller is also used to perform the following leakage current detection method: ① A leakage fault has occurred. The fault alarm is set as leakage in the controlled equipment Bn, causing the three-phase four-wire leakage detection switch at a node of the controlled equipment on the power supply line to trip. Perform the following steps: Step 1.1: The controller first disconnects the B-phase and C-phase circuits, while keeping the A-phase circuit powered on. Step 1.2, Control B n If the residual current circuit breaker can be closed and B... n If the detected leakage current data is qualified, proceed to step 1.3; if the circuit breaker cannot be closed, proceed to step 1.

5. Step 1.3: Control B sequentially n+1 B n+2 ...B n+n If the circuit breaker can be closed, continue the inspection. If the circuit breaker cannot be closed, proceed to step 1.

5. Step 1.4: When phase A is powered, if all residual current circuit breakers at the controlled equipment nodes can be closed, the controller disconnects the phase A and phase C circuits, retains phase B for continued power supply, and repeats steps 1.2-1.3; if all residual current circuit breakers at the controlled equipment nodes can be closed when phase B is powered, the controller disconnects the phase A and phase B circuits, retains phase C for continued power supply, and repeats steps 1.2-1.

3. Step 1.5: The controller supplies power to the B-phase circuit. If the patrol detection detects B... n+x The circuit breaker cannot be closed at point B. n+x+1 After tripping, the controller disconnects the power supply to phase B circuit and controls phase B. n+x If the circuit breaker can be closed, then step 1.5 is executed again, and X is increased by 1, until the circuit breaker cannot be closed. Assume that at this point, when n+x=k, B is detected. k If the circuit breaker cannot be closed at point B, then the leakage fault occurred at point B. k and B k+1 On phase A of the line; ② No leakage fault occurred. The leakage current of the three-phase four-wire circuit measured at the node of the controlled equipment is set as IA1, IA2...IA by the node name. n IB1, IB2...IB n IC1, IC2...IC n If the maximum leakage current of the power supply line between two adjacent controlled device nodes is set to Idmax, then the following steps are performed: Step 2.1: Read IA1, IA2...IA sequentially. n IB1, IB2...IB n IC1, IC2...IC n Calculate the leakage current difference I between two adjacent controlled device nodes. d =I k -I k+1 , if I d dmax Then the controlled device node increments by 1 sequentially until I is measured. d >I dmax If the measured node number of the controlled equipment is t at this time, the fault point occurs between the t and t+1 road segments, and proceed to step 2.2;​ Step 2.2: The controller disconnects the B and C phase circuits, while keeping phase A powered on. The leakage current difference Ita between node t and t+1 of the controlled equipment is measured. Step 2.3: The controller disconnects the A and C phase circuits, while keeping phase B powered on. The leakage current difference Itb between node t and t+1 of the controlled equipment is measured. Step 2.4: The controller disconnects the A and B phase circuits, while retaining the C phase to continue supplying power. The leakage current difference Itc between node t and t+1 of the controlled equipment is measured. Step 2.5: Compare the values ​​of Ita, Itb, and Itc. If Ita is the largest, the fault point is on the A-phase line between the controlled equipment nodes t and t+1; if Itb is the largest, the fault point is on the B-phase line between the controlled equipment nodes t and t+1; if Itc is the largest, the fault point is on the C-phase line between the controlled equipment nodes t and t+1.

2. The leakage current detection system for a power supply line according to claim 1, characterized in that: The controller also includes a display screen, buttons, indicator lights, and / or a buzzer connected to the main control module and the communication module.

3. The leakage current detection system for a power supply line according to claim 1, characterized in that: The controller also includes a timer switch, a latitude and longitude acquisition module, and / or an illuminance detection module, which are respectively connected to the main control module, the three-phase circuit control module, and the N-line circuit control module.

4. The leakage current detection system for a power supply line according to claim 1, characterized in that: The controller also includes an inspection module connected to the main control module and the communication module respectively, for receiving inspection instructions and automatically executing inspection operations.

5. The leakage current detection system for a power supply line according to claim 1, characterized in that: The communication module is configured as 4G, 5G or NB wide area network.

6. The leakage current detection system for a power supply line according to claim 1, characterized in that: The communication module is configured with Zigbee, LoRa, or 433M LAN.

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