Non-contact energy-taking small-current grounding line selection device and line selection method

Abstract

The invention discloses a non-contact energy-taking small current grounding line selection device and line selection method, and belongs to the technical field of power distribution network fault detection. The device comprises a main control unit, a non-contact zero sequence current sensing module, a wireless communication module, a non-contact energy taking module and a protective shell. The sensing module and the energy taking module are integrated into an annular integrated head capable of being opened and closed, a pincer-shaped structure is adopted for sleeving a circuit, and current signal acquisition and electric energy acquisition are achieved. An artificial intelligence algorithm is built in the main control unit, complex fault types such as permanent grounding, intermittent arc grounding and high-resistance grounding can be accurately distinguished, and a diagnosis result is uploaded through the wireless communication module. According to the invention, power-off-free and wiring-free installation is realized in a real sense, the device has the remarkable advantages of convenient installation, flexible energy taking, intelligent diagnosis, wireless remote transmission and low operation and maintenance cost, and the problems that a traditional line selection device is complex in installation and depends on an external power supply and communication wiring are effectively solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of small current grounding line selection, in particular to a small current grounding line selection device and method with non-contact power taking. BACKGROUND

[0002] Small current grounding systems (including ungrounded systems and arc suppression coil grounding systems) are widely used in 3-66kV distribution networks in China. Such systems can still operate with faults for 1 to 2 hours after a single-phase grounding fault occurs, but the fault line must be quickly and accurately identified and located, so the reliability and accuracy of the grounding line selection device are crucial to the safe operation of the power grid.

[0003] Traditional grounding line selection devices mostly use single-chip microcomputers or ordinary industrial control computers as platforms, and are limited by processing power and algorithm performance, so their line selection accuracy is generally not high, especially when facing complex faults such as high-resistance grounding and intermittent arc grounding. In addition, existing devices mostly use contact measurement and wired power supply methods, which are complex to install, require power-off construction, and have poor anti-interference ability and environmental adaptability.

[0004] In the prior art, such as patent CN107329030B, a small current grounding line selection device with convenient installation is proposed, which improves the installation flexibility through mechanical structure optimization (such as telescopic device, fixed sleeve ring, etc.), but still relies on traditional wired sensing and power supply methods, and does not fundamentally solve the problems of complex installation, external power supply, and difficult communication wiring. The device still has limitations such as insufficient adaptability, low intelligence, and dependence on wired data transmission in complex field environments.

[0005] Therefore, there is an urgent need for a new small current grounding line selection device with non-contact power taking, non-contact measurement, wireless communication, and intelligent diagnosis functions to improve installation convenience, operation reliability, and fault diagnosis accuracy. SUMMARY

[0006] (I) Technical problems solved In view of the shortcomings of the prior art, the present application provides a small current grounding line selection device and method with non-contact power taking, which has the advantages of convenient installation, flexible power taking, intelligent diagnosis, and wireless transmission, and solves the problems of complex installation, external power supply, low intelligence, and difficult communication wiring of traditional line selection devices.

[0007] (II) Technical solutions To achieve the above-mentioned purposes of convenient installation, flexible power taking, intelligent diagnosis, and wireless transmission, the present application provides the following technical solutions: The application provides a small-current grounding line selection device with non-contact power taking, comprising: a master control unit for executing a grounding fault line selection algorithm; at least one non-contact zero sequence current sensing module electrically connected with the master control unit and sleeved on a power distribution line in an openable and closable pincer structure, for collecting a zero sequence current signal of the line; a wireless communication module electrically connected with the master control unit, for uploading a line selection result and fault data to a cloud platform or an operation and maintenance center; a non-contact power taking module electrically connected with the master control unit, for obtaining electric energy from the power distribution line on which the module is sleeved through electromagnetic induction, and supplying power to the whole device; and a protective shell for containing the master control unit and the wireless communication module, wherein the shell is provided with a waterproof and dustproof connector, and the zero sequence current sensing module, the power taking module and the master control unit are connected through a flexible cable with a shielding layer.

[0008] The non-contact zero sequence current sensing module and the non-contact power taking module are integrated into an openable and closable annular integrated sensing and power taking head, the annular structure is made of weather-resistant engineering plastic, and a high-precision Rogowski coil and a power taking CT are embedded on the inner side of the annular structure.

[0009] The master control unit comprises: a signal conditioning circuit for amplifying, filtering and AD converting the collected zero sequence current signal; an embedded processor with a time-frequency analysis algorithm and an artificial intelligence model, for executing grounding fault line selection analysis and distinguishing fault types; and a data storage unit for buffering fault waveform data and device operation logs.

[0010] The artificial intelligence model is a fault diagnosis model trained based on a deep convolutional neural network, and can distinguish permanent grounding, intermittent arc grounding and high resistance grounding fault types.

[0011] The wireless communication module adopts a 4G / 5G or LoRa communication mode, supports timely reporting of device state information, and actively uploads a line selection report containing fault time, line number and fault type after diagnosing a grounding fault.

[0012] The application further comprises a self-diagnosis unit electrically connected with the master control unit, for periodically self-calibrating the measurement accuracy of the zero sequence current sensing module, and monitoring the output voltage and power of the power taking module, and sending device abnormal alarm information through the wireless communication module when an abnormality occurs.

[0013] The protective shell is provided with a fixing structure of a high-strength magnet and / or a bandage on the outer wall, for adsorbing or fixing the device main body on a metal member or a tower near the site, and the protection level of the shell is not less than IP65.

[0014] The non-contact power taking small current grounding line selection device also provides a line selection method of the non-contact power taking small current grounding line selection device. S1: obtaining working power from the connected power distribution line through the non-contact power taking module to power the entire device; S2: continuously monitoring the zero sequence current signal on the power distribution line through the non-contact zero sequence current sensing module; S3: when detecting an abnormal zero sequence current, the main control unit starts high-frequency sampling and records fault data; S4: the main control unit calls the grounding fault line selection algorithm for on-site analysis to complete fault line selection and diagnosis; S5: uploading the line selection diagnosis result and fault data to the cloud platform or operation and maintenance center through the wireless communication module.

[0015] (Three) beneficial effects Compared with the prior art, the non-contact power taking small current grounding line selection device and the line selection method have the following beneficial effects: The non-contact power taking small current grounding line selection device and the line selection method directly take power from the line electromagnetic induction through the non-contact power taking module, and realize truly isolated installation by combining with the non-contact clamp sensing design, without additional power supply line and power-off construction, greatly improving the installation convenience and safety, and reducing the operation and maintenance cost.

[0016] The non-contact power taking small current grounding line selection device and the line selection method adopt the annular integrated design integrating sensing and power taking, and the weather-resistant engineering plastic material ensures the reliability of long-term outdoor operation, and significantly saves the installation time.

[0017] The non-contact power taking small current grounding line selection device and the line selection method have wireless remote transmission function and IP65 high protection level, support 4G / 5G or LoRa communication, can realize automatic reporting of fault information and line selection report, and the operation and maintenance personnel do not need to check on site, improving the response speed and management efficiency. At the same time, the self-diagnosis function can realize the monitoring and early warning of the state of the device itself, further improving the reliability and maintainability of the system operation. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 The structure principle of the application; Figure 2 The installation schematic diagram of the device in the first embodiment of the application when performing line selection work; Figure 3 The method flowchart in the second embodiment of the application.

[0019] In the figure: 100, master control unit; 200, zero sequence current sensing module; 300, wireless communication module; 400, non-contact power taking module; 500, protective shell; 600, connector; 700, flexible cable; 800, self-diagnosis unit; 900, fixing structure. DETAILED DESCRIPTION

[0020] The application will be described in detail below in conjunction with the drawings and specific embodiments.

[0021] Embodiment 1 Please refer to Figure 1 and Figure 2 A small current grounding line selection device with non-contact power taking, comprising: a master control unit 100 for executing a grounding fault line selection algorithm; at least one non-contact zero sequence current sensing module 200, which is electrically connected with the master control unit 100 and is sleeved on a power distribution line in a openable and closable clamp structure, for collecting zero sequence current signals of the line; a wireless communication module 300, which is electrically connected with the master control unit 100, for uploading line selection results and fault data to a cloud platform or an operation and maintenance center; a non-contact power taking module 400, which is electrically connected with the master control unit 100, for obtaining power from the power distribution line it is sleeved on through electromagnetic induction and supplying power for the entire device; a protective shell 500 for accommodating the master control unit 100 and the wireless communication module 300, the shell being provided with a waterproof and dustproof connector 600, and the connection part connecting the zero sequence current sensing module 200, the power taking module and the master control unit 100 through a flexible cable 700 with a shielding layer.

[0022] The small current grounding line selection device with non-contact power taking completely solves the pain points of the traditional line selection device, such as the need for additional power supply line and voltage transformer, complex installation, and large influence of power failure. Through the non-contact power taking module 400, power is directly obtained from the line electromagnetic induction, and combined with the non-contact clamp sensing design, truly isolated installation is realized, without additional power supply line and power failure construction, the construction time is shortened from several hours to within ten minutes, greatly improving the installation convenience and safety, and reducing the operation and maintenance cost.

[0023] In this embodiment, the non-contact zero sequence current sensing module 200 and the non-contact power taking module 400 are integrated into a openable and closable ring-shaped integrated sensing and power taking head. The ring-shaped structure is made of weather-resistant engineering plastic, and the inner side is respectively embedded with a high-precision Rogowski coil and a power taking CT. It should be noted that the zero sequence current sensing module 200 detects the fault current through electromagnetic induction, and the power taking module needs to obtain energy from the same magnetic field. If the distance between the two coils is too close or the winding method is improper, the sensing signal may be disturbed by the load effect of the power taking circuit, or the power taking efficiency may be reduced due to the magnetic field offset of the sensing module. Therefore, by setting a permalloy shield between the two coils, the influence of the magnetic leakage generated by the power taking CT on the measurement accuracy of the Rogowski coil can be effectively suppressed, and the magnetic field of the Rogowski coil can also be avoided to weaken the power taking efficiency of the power taking CT. This design ensures that when the fault current is small or the line load is low, the device can still realize high-precision measurement and stable power taking at the same time.

[0024] In this embodiment, the main control unit 100 includes: a signal conditioning circuit for amplifying, filtering and AD converting the collected zero sequence current signal; an embedded processor with built-in time-frequency analysis algorithm and artificial intelligence model for performing ground fault line selection analysis and distinguishing fault types; a data storage unit for buffering fault waveform data and device operation log. It should be noted that the signal conditioning circuit is not a simple fixed gain amplifier, but a dynamic gain adjustment scheme using a programmable gain amplifier (PGA) combined with a digital potentiometer. The main control unit 100 monitors the input signal amplitude in real time. If it is judged to be a normal load current, a lower gain is used to ensure the measurement dynamic range. Once a current mutation that may be a ground fault is detected, it automatically switches to a high gain mode to amplify the weak fault characteristic signal, thereby greatly improving the detection sensitivity of high resistance ground faults without saturation. The filter circuit uses a combination of analog and digital filtering to effectively suppress complex electromagnetic interference in the field.

[0025] In this embodiment, the artificial intelligence model is a fault diagnosis model trained based on a deep convolutional neural network, which can distinguish permanent ground, intermittent arc ground and high resistance ground fault types. It should be noted that the training data of the artificial intelligence model comes from a large number of field recording data and simulation data, covering complex working conditions of different grounding resistances, different fault closing angles, different line parameters and common noise interference in the field. The input of the model is the multi-line zero sequence current transient time series data and its wavelet transform time-frequency diagram after pre-processing and feature extraction, which automatically learns the fault features through convolutional layers, and finally outputs the fault probability of each line and the specific fault type classification. The advantage of this method is that it does not need to rely on manual feature extraction, and can adaptively learn the most essential and subtle differences in the fault, especially for intermittent arc ground and high resistance ground faults that are not obvious, its recognition accuracy is significantly improved compared with traditional amplitude method, five harmonic method, etc.

[0026] In this embodiment, the wireless communication module 300 adopts 4G / 5G or LoRa communication mode, supports timely reporting of device state information, and actively uploads the selected line report containing fault time, line number and fault type after diagnosing the ground fault. It should be noted that the wireless communication module 300 is built-in with a perfect network management mechanism. In the case of good signal, 4G / 5G network is preferred for fast transmission of large data (such as fault recording data); in the case of weak signal coverage in remote stations, it can automatically switch to low-power wide-area network technologies such as LoRa to ensure that the state information and small data of the selected line result can be reliably uploaded. All communication processes use encryption and verification mechanisms to ensure data security. The module also supports remote configuration and firmware upgrade functions, greatly facilitating later operation and maintenance.

[0027] In this embodiment, it also includes a self-diagnosis unit 800 electrically connected with the main control unit 100, which is used for periodic self-calibration of the measurement accuracy of the zero sequence current sensing module 200, and monitors the output voltage and power of the power taking module. When abnormal, it sends device abnormal alarm information through the wireless communication module 300. It should be noted that the self-diagnosis function is the key to ensure the long-term reliability of the device. The self-diagnosis unit 800 controls a high-precision calibration source to inject a standard sinusoidal signal with known amplitude and phase into the signal conditioning front end periodically (such as once a day), automatically calculates the gain error and phase error of the current measurement channel by comparing the AD sampling result with the theoretical value, and performs software compensation in the subsequent calculation, realizing online self-calibration of measurement accuracy and effectively avoiding measurement error drift caused by device aging, temperature drift and other factors. At the same time, it continuously monitors the output of the power taking module. If the power taking voltage is found to be abnormally low, it can be judged that the line may be in a long-term light load state. At this time, the main control unit 100 will automatically switch to the built-in backup lithium battery for power supply, and report the "insufficient power taking" alarm to remind the operation and maintenance personnel to pay attention.

[0028] In this embodiment, the outer wall of the protective shell 500 is provided with high-strength magnets and / or a fixing structure 900 of a binding belt, which is used to adsorb or fix the device body on a metal member or tower near the site, and the protection level of the shell is not less than IP65. It should be noted that the shell is integrally injection molded by ASA+PC engineering plastic, which has extremely high strength, weather resistance, ultraviolet resistance and high and low temperature resistance (working temperature range -40°C~+85°C), and can adapt to outdoor harsh climate environment. The protection level of IP65 ensures the safety of internal electronic components of the device in rain, snow and sand environment. Various installation methods (magnetic attraction, binding belt) make the installation extremely flexible and convenient, without the need to drill holes on the tower, truly realizing power-free and non-destructive installation, greatly reducing the implementation difficulty and cost.

[0029] Embodiment 2 Please refer to Figure 3 A line selection method of a small current grounding line selection device with non-contact power taking, comprising the following steps: Step 1: obtaining working power from the connected power distribution line through the non-contact power taking module 400 to power the entire device; The power taking module has an intelligent control circuit built-in, which has a soft start function to prevent power-on impact current from damaging the subsequent circuit; it also has an overvoltage and overcurrent protection function, which can automatically cut off and protect the subsequent circuit when the line encounters lightning or short circuit fault and generates a large current, and automatically recovers after the fault is eliminated.

[0030] Step 2: continuously monitor the zero sequence current signal on the power distribution line through the non-contact zero sequence current sensing module 200; the monitoring process is full-cycle continuous sampling, and the basic sampling rate is 4kHz, which is sufficient to accurately capture the power frequency 50Hz signal.

[0031] Step 3: when the zero sequence current anomaly is detected, the main control unit 100 starts high-frequency sampling and records fault data; the starting criterion of "zero sequence current anomaly" is that the zero sequence current amplitude exceeds the preset threshold value (which can be adjusted) and the duration exceeds 10ms to avoid transient interference. Once triggered, the main control unit 100 immediately increases the sampling rate to more than 20kHz, and continuously records the multi-cycle waveform data of the whole process before, during and after the fault recovery, providing complete information for subsequent analysis.

[0032] Step 4: The master control unit 100 calls the grounding fault line selection algorithm for on-site analysis, completes fault line selection and diagnosis; the line selection algorithm adopts a comprehensive decision-making strategy of "combining transient group amplitude and phase comparison method with artificial intelligence judgment results". First, the traditional algorithm quickly calculates the amplitude, direction and high-frequency component energy of the transient zero sequence current of each line, and gives a preliminary line selection result. At the same time, the artificial intelligence model analyzes the fault waveform characteristics in depth, and gives another line selection result and fault type probability. Finally, the master control unit 100 makes a weighted decision according to the confidence of the two results to generate a final report. This fusion algorithm takes into account the quick and reliable of traditional methods and the intelligent and accurate of AI methods, significantly reducing the misjudgment and omission rate.

[0033] Step 5: Upload the line selection diagnosis result and fault data to the cloud platform or operation and maintenance center through the wireless communication module 300. The uploaded data packet is compressed and encapsulated, containing key information such as fault time, line number, fault type, fault current amplitude, and fault waveform data file for advanced analysis. Operation and maintenance personnel can receive alarms and view detailed reports in real time on the mobile APP or PC monitoring platform, quickly locate the fault point and guide the line patrol.

[0034] The above is only an embodiment of the present application, and does not limit the patent scope of the present application, and any equivalent structure or equivalent flow transformation using the content of the present application specification and drawings, or direct or indirect application in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A small current earth selection device for non-contact power taking, characterized in that, The utility model relates to a kind of ground fault line selection device, including: A master unit is used to execute ground fault line selection algorithm; At least one non-contact zero sequence current sensing module is electrically connected to the master unit and is connected to the power distribution line in a detachable clamp structure, for collecting line zero sequence current signal; A wireless communication module is electrically connected to the master unit, for uploading line selection results and fault data to the cloud platform or operation and maintenance center; A non-contact power module is electrically connected to the master unit, and obtains power from the power distribution line it is connected to through electromagnetic induction, and powers the entire device; A protective shell is used to contain the master unit and the wireless communication module, the shell is provided with a waterproof and dustproof connector, and the connector connects the zero sequence current sensing module, the power module and the master unit through a flexible cable with a shielding layer.

2. A small current earthed line selector device according to claim 1, characterized in that: The non-contact zero sequence current sensing module and the non-contact power module are integrated into a detachable ring-shaped integrated sensing and power module. The ring-shaped structure is made of weather-resistant engineering plastic, and the inner side is embedded with a high-precision Rogowski coil and a power CT.

3. A small current earthed line selector device as claimed in claim 1, wherein: The master unit includes: A signal conditioning circuit is used to amplify, filter and AD convert the collected zero sequence current signal; An embedded processor is built-in with time-frequency analysis algorithm and artificial intelligence model, for executing ground fault line selection analysis and distinguishing fault types; A data storage unit is used to cache fault waveform data and device operation log.

4. A small current earthed line selector device according to claim 3, characterized in that: The artificial intelligence model is a fault diagnosis model trained based on deep convolutional neural network, which can distinguish permanent ground fault, intermittent arc ground fault and high resistance ground fault.

5. A small current earthed line selector device as claimed in claim 1, wherein: The wireless communication module uses 4G / 5G or LoRa communication mode, supports timely reporting of device state information, and actively uploads line selection reports containing fault time, line number and fault type after diagnosing ground fault.

6. A small current earthed line selector device as claimed in claim 1, wherein: It also includes a self-diagnosis unit electrically connected to the master unit, which is used for periodic self-calibration of the measurement accuracy of the zero sequence current sensing module, and monitors the output voltage and power of the power module. When abnormal, send device abnormal alarm information through the wireless communication module.

7. A small current earth selection device according to claim 1, characterized in that: The protective shell is provided with a high-strength magnet and / or a fixing structure of a bandage on the outer wall, for adsorbing or fixing the device body on the metal member or tower near the scene, and the protection level of the shell is not less than IP65.

8. A fault line selection method based on the low-current grounding line selection device according to any one of claims 1-7, characterized in that, The steps include: S1: obtain working power from the power distribution line connected to the non-contact power module, power the entire device; S2: continuously monitor the zero sequence current signal on the power distribution line through the non-contact zero sequence current sensing module; S3: when detecting abnormal zero sequence current, the master unit starts high-frequency sampling and records fault data; S4: the master unit calls the ground fault line selection algorithm for on-site analysis, completes fault line selection and diagnosis; S5: upload the line selection diagnosis results and fault data to the cloud platform or operation and maintenance center through the wireless communication module.

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