A 10kV fixed external series gap lightning arrester fault identification method

Abstract

The application provides a 10kV fixed external series gap lightning arrester fault identification method, which comprises the following steps: a power supply is obtained by an induction power circuit using a power frequency alternating current field to transform induced charge, so as to provide working power supply for a fault diagnosis circuit and a fault indication module; a voltage gradient detection circuit collects a power frequency alternating current signal of the 10kV fixed external series gap lightning arrester and converts the signal into a direct current level signal; the fault diagnosis circuit detects the direct current level signal to determine whether the lightning arrester is faulty; and the fault indication module sends an alarm indication signal when the fault diagnosis circuit detects that the lightning arrester is faulty. The application can check and replace the aging 10kV fixed external series gap zinc oxide lightning arrester in the line in advance, so as to prevent the occurrence of line operation accidents and the expansion of faults.

Description

Technical Field

[0001] This invention relates to the field of fault diagnosis technology for 10kV distribution network line surge arresters, specifically a fault identification method for 10kV fixed external series gap surge arresters. Background Technology

[0002] Since its development in the 1960s, zinc oxide surge arresters have been widely used. Currently, 10kV distribution network line lightning protection mainly uses zinc oxide surge arresters with external series gaps. In 2020, the State Grid Corporation of China proposed requirements for the standardization of 10kV distribution network line surge arresters, recommending typical design cases for fixed external series gap zinc oxide surge arresters, which began to be promoted and implemented in July 2021. Currently, there is still a lack of effective technical means for fault diagnosis of 10kV fixed external series gap zinc oxide surge arresters.

[0003] Currently, the testing methods or online monitoring devices for line surge arresters can be broadly classified into several categories:

[0004] 1. Current transformers detect leakage current in the transformer body. By separating resistive and capacitive currents from the total current, the aging degree of the transformer body can be determined by the magnitude of the resistive current.

[0005] Invention patent CN1123629870A provides a surge arrester fault diagnosis method based on robust estimation. This method uses robust estimation to identify outliers in the sampled leakage current data, distinguishing between continuous valid outliers and isolated intermittent outliers. This effectively eliminates the influence of manual operation and environmental interference on the data, obtaining effective data samples for judging the surge arrester's operating status. This improves the reliability of the fault analysis data source and reduces the probability of misjudgment. However, this method is not suitable for 10kV fixed external series gap surge arresters due to the isolation provided by the external series gap.

[0006] Invention patent CN112147435A and an online detection device for surge arresters in switchgear include: an AD signal acquisition module. It mainly determines the state of the surge arrester by acquiring the total leakage current of the arrester and separating the resistive and capacitive currents. As mentioned above, 10kV fixed external series gap surge arresters are not suitable for 10kV leakage current detection methods due to the isolation effect of the external series gap.

[0007] Invention patent CN112269142A discloses a surge arrester testing device and method. The testing device includes a leakage current acquisition module, a control module, and an indication module. However, the leakage current acquisition method is not applicable to 10kV fixed external series gap surge arresters.

[0008] 2. The lifespan of the surge arrester can be determined by the number of lightning strikes through lightning current detection or lightning current-driven counting.

[0009] Utility model patent CN210487888U provides a surge arrester detection device, including a stainless steel housing. It represents a structural modification of an existing surge arrester lightning strike action counter, adding an electromagnetic shield and a 4G communication module, aiming to solve the technical problems of existing surge arrester detectors being prone to failure and inconvenient data reading. However, it does not have the function of real-time monitoring of the surge arrester's status.

[0010] Utility model patent CN208833872U discloses a surge arrester testing device and system. The surge arrester testing device includes a signal acquisition unit, a counting unit, and an alarm unit. This utility model determines the lifespan of the surge arrester by detecting the number of lightning current impacts, but lacks accurate detection and judgment of the aging degree of the internal resistive elements.

[0011] The utility model patent CN212646863U discloses a surge arrester detector with a warning mechanism, which mainly adds a glare light and a buzzer alarm to the traditional lightning counter, without involving any innovation in the technical principle of fault detection.

[0012] 3. Integrating lightning current detection, leakage current detection, conversion circuit, alarm device, communication module and background management system to realize online monitoring of surge arresters, etc., is expensive.

[0013] Invention patent CN113161090A discloses a zinc oxide surge arrester, consisting of a composite-jacketed zinc oxide surge arrester, a top bolt, and an intelligent detection module. Its built-in current inductor coil is used to detect current, and simultaneously measures the leakage current and the number of lightning strikes on the zinc oxide surge arrester. However, due to the leakage current being in the μA range, accurate measurement is difficult. The circuit uses solar charging and battery power, resulting in high costs. Its use of narrowband IoT communication for real-time speed and BeiDou positioning for accurate and convenient location further increases the cost of the device and the maintenance costs of the back-end management system. The high cost makes it difficult to widely apply in the range of inexpensive 10kV voltage level surge arresters.

[0014] Invention patent CN112782509A describes a surge arrester detection system, comprising a vertically installed surge arrester, a detection module, a control module, a communication module, and a backend management module. The detection module determines the degree of surge arrester offset to indicate whether the arrester is faulty. The control module issues an alarm signal, the communication module transmits the surge arrester identification code and location information, and the backend management module enables human-machine interaction. However, the fault diagnosis criteria of this invention are questionable. Furthermore, the various detection, judgment, communication, and backend systems are costly and not suitable for detecting the status of surge arresters at low voltage levels (10kV). Additionally, the lifespan and continuous power supply capability of the described solar power supply mode, its suitability for prolonged cloudy or rainy weather, and its construction and maintenance costs are all debatable.

[0015] Invention patent CN112782502A provides a surge arrester detection system based on multiple signal acquisition. The system includes a leakage current acquisition unit, a temperature acquisition unit, a current / voltage conversion unit, an A / D conversion unit, a control processing unit, a storage unit, an alarm unit, and a communication unit. This invention determines the surge arrester's status through leakage current detection and transmits data to a backend monitoring system via wireless communication. However, 10kV fixed external series gap surge arresters, due to the isolation provided by the external series gap, are not suitable for 10kV leakage current detection. Furthermore, this detection system, which includes acquisition, calculation, control, alarm, communication, and backend monitoring systems, is costly and unsuitable for detecting inexpensive 10kV voltage level surge arresters, making its widespread application difficult.

[0016] Chinese invention patent CN112816801A discloses a transformer surge arrester testing system, including an industrial host, a switching line device, and testing components. This invention mainly integrates the functions of a fully automatic turns ratio tester, a DC resistance tester, a loop resistance tester, and a capacity no-load tester to achieve comprehensive testing of transformer surge arresters. However, it is not suitable for fault detection and diagnosis of line surge arresters.

[0017] Invention patent CN110926421A discloses a tilt damage early warning and detection device for surge arresters on the transformer side of a distribution area, including a tilt detection device body and a back-end management center. Based on LoRa wireless transmission technology and tilt sensor information acquisition technology, it can provide timely early warning when the surge arrester on the distribution area transformer experiences tilt damage. When lightning strikes damage the surge arrester and cause a power outage, it can quickly locate the damaged surge arrester, assisting maintenance personnel in replacing the surge arrester in a timely manner and shortening the power outage time.

[0018] Currently, mature online monitoring devices for surge arresters are expensive, and given the large number and wide distribution of 10kV distribution network towers, their cost-effectiveness is too low for the already inexpensive 10kV surge arresters, hindering their widespread application. Furthermore, the isolation effect of the external series gap prevents the application of certain techniques, such as leakage current detection. Therefore, the development of an economical, effective, and inexpensive fault identification device for 10kV fixed external series gap surge arresters is particularly important and urgent. Summary of the Invention

[0019] To address the above problems, this invention proposes a fault identification method for 10kV fixed external series gap surge arresters. This method determines whether the surge arrester body has aged by detecting whether the potential gradient of the built-in resistor proportional unit has changed significantly, and sends an alarm indication signal to the operation and maintenance department so as to identify and replace aging 10kV fixed external series gap zinc oxide surge arresters in the line in advance, thereby preventing the occurrence of line operation accidents and the expansion of the fault area.

[0020] The present invention adopts the following technical solution to solve the above-mentioned technical problems:

[0021] A fault identification method for a 10kV fixed external series gap surge arrester employs a fault identification device. The fault identification device includes an inductive power supply circuit, a voltage gradient detection circuit, and a fault identification circuit. The fault identification circuit includes a fault diagnosis circuit and a fault indication module. The method comprises:

[0022] The inductive power-gathering circuit obtains system power by transforming induced charges through a power frequency AC electric field via spatial coupling, so as to provide working power for the fault diagnosis circuit and fault indication module.

[0023] The voltage gradient detection circuit acquires the power frequency AC signal of the 10kV fixed external series gap surge arrester and converts the acquired power frequency AC signal into a DC level signal.

[0024] The fault diagnosis circuit detects the DC level signal obtained by the voltage gradient detection circuit to determine whether the surge arrester has failed.

[0025] The fault indication module issues an alarm indication signal when the fault diagnosis circuit detects a fault in the surge arrester.

[0026] Furthermore, the inductive power collection circuit is a disc-shaped conductive plate, including a power collection disk and power collection terminals. The power collection disk is located below the 10kV overhead line, and the disk surface is parallel to the conductor. Through the transformation of the power frequency AC electric field, the electric field strength on the disk surface changes, and the induced charge from the changing field strength converges at the power collection terminals.

[0027] Furthermore, the fault identification device also includes a power cord and a grounding wire. The power terminal is connected to one end of the power cord via a fastener, and the other end of the power cord is connected to the internal fault diagnosis circuit. One end of the grounding wire is connected to the earth, and the other end is connected to the internal fault diagnosis circuit.

[0028] Furthermore, the 10kV fixed external series gap zinc oxide surge arrester includes a surge arrester body, on which the voltage gradient detection circuit and the fault identification circuit are installed.

[0029] Furthermore, the voltage gradient detection circuit includes a voltage sampling wire, a series-connected composite jacket insulator insulation resistor, and several zinc oxide resistance plates. The voltage sampling wire is led out from the upper end of one zinc oxide resistance plate adjacent to the low voltage end, and outputs a DC level signal after sampling.

[0030] Furthermore, the fault identification circuit includes a cylindrical housing, a fault diagnosis circuit installed on the cylindrical housing, and a fault indication module, wherein the fault indication module consists of indicator lights symmetrically arranged around the circumference of the cylindrical housing.

[0031] Furthermore, the cylindrical housing is also provided with an inlet hole and an axial fixing hole. The inlet hole is used to pass through the power line and the grounding wire; the axial fixing hole is a through hole used to pass through the bottom bolt of the 10kV fixed external series gap zinc oxide surge arrester. The bottom bolt is fixed together as a whole by fasteners.

[0032] Furthermore, the fault identification device also includes a rectifier circuit connected to the inductive power supply circuit. The fault diagnosis circuit has a built-in voltage comparison circuit and an indicator light driving circuit. The rectifier circuit is used to rectify the AC induced charge obtained from the power supply line from the power supply terminal of the power supply panel and the grounding wire from the ground, and then stabilize and output it as the power supply for the built-in voltage comparison circuit and the indicator light driving circuit.

[0033] Furthermore, the voltage comparison circuit is used to compare the DC level signal output by the voltage gradient detection circuit with a given threshold and output a logic level signal to determine whether the integrated 10kV fixed external series gap surge arrester is in good condition; the indicator light driving circuit is used to amplify the received logic level signal and drive the fault indication module to issue an alarm indication signal.

[0034] The beneficial effects of this invention are as follows:

[0035] 1. Since the 10kV fixed external series gap zinc oxide surge arrester has external series gap isolation, it is impossible to rely on full current detection and separation of resistive current to determine whether the body is deteriorated. This invention detects and determines whether the body is deteriorated by detecting the voltage drop change of the built-in zinc oxide resistive element proportional unit, thus solving the technical problem that this type of surge arrester cannot be detected online.

[0036] 2. This invention obtains power through spatial electric field induction on a metal plate surface, without any contact with wires, making it safe and reliable. The power extraction time is not affected by various factors such as space and weather. It does not require energy storage, nor does it require high-cost power supply methods such as existing battery power supply or solar power supply. It has the advantages of simple structure, uninterrupted power supply, and low cost for widespread application.

[0037] 3. The fault diagnosis of this invention consists of a simple voltage sampling and voltage comparison circuit and a light-emitting diode indicator. The device only requires a few electronic components and is cured with epoxy resin potting compound. It forms an integrated structure with a 10kV fixed external series gap zinc oxide surge arrester. It has the advantages of low price, accurate fault indication and maintenance-free operation, and provides an economical and effective solution for the widespread application of online monitoring of 10kV distribution network line lightning protection devices. Attached Figure Description

[0038] Figure 1 This is an electrical schematic diagram of the fault identification method for a 10kV fixed external series gap surge arrester according to the present invention;

[0039] Figure 2 This is a schematic diagram of the overall structure and layout of the 10kV fixed external series gap surge arrester fault identification device of the present invention;

[0040] Figure 3 This is a schematic diagram of the structure of a 10kV fixed external series gap zinc oxide surge arrester in an embodiment of the present invention;

[0041] Figure 4 This is a schematic diagram of the fault identification device in an embodiment of the present invention;

[0042] Figure 5 This is an electrical schematic diagram of the rectifier circuit in an embodiment of the present invention;

[0043] Figure 6 This is a schematic diagram of the voltage comparison circuit and indicator light driving circuit built into the fault diagnosis circuit in this embodiment of the invention;

[0044] Figure 7 This is a schematic diagram of the inductive power extraction circuit in an embodiment of the present invention;

[0045] Figure 8 This is a schematic diagram of the sampling voltage sampling structure according to an embodiment of the present invention.

[0046] The reference numerals in the figure are described below:

[0047] 1-10kV fixed external series gap zinc oxide surge arrester; 11-Surge arrester body; 12-Fault identification circuit; 13-Voltage sampling wire;

[0048] 121-Fault indication module; 122-Inlet hole; 123-Axial fixing hole; 124-Cylindrical housing; 125-Fault diagnosis circuit;

[0049] 2-Inductive power supply circuit; 21-Power supply panel; 22-Fixed insulating rod; 23-Fixing hole; 24-Power supply terminal;

[0050] 3-Fixed hardware;

[0051] 4-Power cord;

[0052] 5-Grounding wire. Detailed Implementation

[0053] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0054] Please see Figure 1-8 This invention provides a fault identification method for a 10kV fixed external series gap surge arrester, employing a fault identification device. The fault identification device includes a 10kV fixed external series gap zinc oxide surge arrester 1, an inductive power supply circuit 2, fixing hardware 3, a power line 4, a grounding wire 5, a voltage gradient detection circuit installed on the 10kV fixed external series gap zinc oxide surge arrester 1, and a fault identification device 12. The fault identification device 12 includes a fault diagnosis circuit 125 and a fault indication module 121. The fault identification method includes the following steps:

[0055] The inductive power-gathering circuit obtains system power by transforming induced charges through a power frequency AC electric field via spatial coupling, so as to provide working power to the voltage gradient detection circuit, fault diagnosis circuit, and fault indication module.

[0056] The voltage gradient detection circuit acquires the power frequency AC signal of the 10kV fixed external series gap surge arrester and converts the acquired power frequency AC signal into a DC level signal.

[0057] The fault diagnosis circuit 125 detects the DC level signal obtained by the voltage gradient detection circuit to determine whether the surge arrester has failed.

[0058] The fault indication module 121 issues an alarm indication signal when the fault diagnosis circuit detects a fault in the surge arrester.

[0059] The 10kV fixed external series gap zinc oxide surge arrester 1 and the inductive power supply circuit 2 are fixed to the crossarm of the tower by fixing hardware 3. Figure 7 As shown, the inductive power-taking circuit 2 is a disc-shaped conductive plate, including a power-taking disk 21, a fixed insulating rod 22, a fixing hole 23, and a power-taking terminal 24. The power-taking disk 21 is located below the 10kV overhead line, and the disk surface is parallel to the conductor. Through the transformation of the power frequency AC electric field, a change in the electric field strength on the disk surface is induced, and the induced charge from the changing field strength converges at the power-taking terminal 24. The power-taking terminal 24 is connected to one end of the power line 4 via fasteners, and the other end of the power line 4 passes through the inlet hole 122 of the 10kV fixed external series gap zinc oxide surge arrester 1 (e.g., ...). Figure 4 (As shown) is connected to the internal fault diagnosis circuit 125.

[0060] One end of the grounding wire 5 is connected to the earth, and the other end is connected to the internal fault diagnosis circuit 125 through the inlet hole 122 of the 10kV fixed external series gap zinc oxide arrester 1. The purpose is to lead the zero potential of the earth to the fault diagnosis circuit 125, which together with the power supply line 4 constitutes the power supply.

[0061] like Figure 3 As shown, the 10kV fixed external series gap zinc oxide surge arrester 1 includes an arrester body 11, on which a voltage gradient detection circuit and a fault identification device 12 are provided. The arrester body 11 is a currently conventional and mature product, including typical design cases of fixed external series gap zinc oxide surge arresters recommended in the 2020 State Grid 10kV distribution network line surge arrester standardization construction.

[0062] The internal structure of the surge arrester body 11 is as follows Figure 8 As shown, a fixed gap structure is formed by a composite jacket insulator, which is then connected in series with zinc oxide resistance sheets. The voltage gradient detection circuit includes a voltage sampling conductor 13, a series-connected composite jacket insulator insulation resistance R0, and several zinc oxide resistance sheets. In this embodiment, four zinc oxide resistance sheets (R1-R4) are connected in series and stacked together. The voltage sampling conductor 13 is led out from the upper end (high voltage end) of one zinc oxide resistance sheet adjacent to the low voltage end, and the sampling voltage is UR4. The input of the voltage gradient detection circuit is taken from a 10kV fixed external series gap surge arrester. The sampling point is near the proportional unit of the zinc oxide resistance sheet at the low voltage end. The collected power frequency AC signal is converted into a DC level signal for use as the input of the fault diagnosis circuit 125.

[0063] According to design standards, the insulation resistance R0 of composite jacket insulators is typically around 10000MΩ, while that of brand-new, qualified zinc oxide resistance sheets is around 2500MΩ. Specifically, R1≈R2≈R3≈R4≈625MΩ. When the high-voltage end of a 10kV fixed external series gap zinc oxide surge arrester is connected to a high-voltage conductor, the relatively low voltage of the high-voltage conductor is 5.77kV. Based on resistance voltage division calculations, the composite jacket insulator bears approximately 4.6kV of the voltage drop UR0 caused by R0. The voltage UR4 obtained by voltage sampling conductor 13 is:

[0064]

[0065] When the zinc oxide resistor element ages, the sampling voltage amplitude decreases due to the reduced insulation resistance. Based on the calculation that the leakage circuit of a zinc oxide surge arrester should not exceed 50μA at 0.75 times its rated voltage, the zinc oxide resistor element is considered aged when its insulation resistance drops to 300MΩ. At this point, R4 is approximately 75MΩ, therefore:

[0066]

[0067] For example, when the sampled voltage UR4 ≤ 42V, it can be determined that the zinc oxide resistor is aged and needs to be replaced. The voltage sampling method is simple and effective, and the higher amplitude voltage sampling makes the fault diagnosis more accurate, providing a simpler and more effective method for predicting in advance whether the surge arrester is aging and needs to be replaced.

[0068] like Figure 4 As shown, the fault identification device 12 includes a cylindrical housing 124, a fault diagnosis circuit 125 installed on the cylindrical housing 124, and a fault indication module 121. The fault indication module 121 can be an indicator light symmetrically arranged around the circumference of the cylindrical housing 124. The cylindrical housing 124 is also provided with a wire inlet hole 122 and an axial fixing hole 123.

[0069] The fault identification device 12 is a cylindrical body encapsulated in a plastic shell, with indicator lights symmetrically arranged along its outer circumference, making it easily observable from any direction by a patrol drone or telescope. The inlet hole 122 serves as the entrance for the power line 4 and the grounding wire 5, introducing power into the internal fault diagnosis circuit 125. The axial fixing hole 123 is a through hole through which the bottom bolt of the 10kV fixed external series gap zinc oxide surge arrester 1 passes, and is fixed to it as a single unit using fasteners.

[0070] Preferably, the 10kV fixed external series gap surge arrester fault identification device of the present invention further includes a rectifier circuit connected to the inductive power supply circuit 2. The fault diagnosis circuit 125 is powered by the rectifier circuit, and the fault diagnosis circuit 125 has a built-in voltage comparison circuit and an indicator light driving circuit (such as...). Figure 6 (As shown).

[0071] like Figure 5 As shown, the rectifier circuit rectifies and regulates the AC induced charge obtained from the power line 4 from the power take-up terminal 24 and the grounding wire 5 from the ground, providing a stable output as the power supply for the built-in voltage comparison circuit and indicator light drive circuit. The voltage comparison circuit compares the DC level signal output by the voltage gradient detection circuit with a given threshold, outputting a logic level signal to determine whether the integrated 10kV fixed external series gap surge arrester is in good condition. The voltage comparison circuit is a traditional operational amplifier comparator. It compares the non-inverting input level signal of the operational amplifier with the given level signal at the inverting input terminal. When the input level signal is greater than the given level signal, the output of the operational amplifier comparator changes from low to high, realizing a fault signal output. The given threshold is obtained through statistical calculations of the insulation resistance of numerous zinc oxide surge arresters to obtain a relatively accurate value for assessing the degree of degradation of the zinc oxide resistor sheet.

[0072] Specifically, the voltage comparison circuit is implemented by a single operational amplifier. The low-voltage side ratio unit sampling voltage of the surge arrester body 11 is obtained by the voltage sampling wire 13, and after voltage division, the sampling voltage Ua (i.e., UR4) is obtained and transmitted to the non-inverting input terminal of the comparison circuit. The built-in given threshold Ub is connected to the inverting input terminal of the comparison circuit. Based on the aforementioned estimation results, the given voltage Ub can be set to 50V. When Ua > 50V, the comparator output level signal does not reverse, and the system considers the surge arrester body 11 to be without aging, with good performance, and can continue to be used. Conversely, when Ua < 50V, the comparator output level signal reverses, driving the indicator light drive circuit, illuminating the indicator light, and the fault diagnosis circuit 125 issues a warning signal, informing that the surge arrester body 11 has aged and needs to be replaced.

[0073] The entire fault diagnosis circuit requires very few electronic components and can be encapsulated and cured in a plastic shell using epoxy resin potting compound in one go. It has advantages such as low cost, safety and reliability, and maintenance-free application.

[0074] The voltage level of a 10kV overhead line is based on the ground as a zero potential reference. If the distance between the conductor and the ground is h, and the conductor voltage is U, then the average electric field strength between the conductor and the ground is E = U / h. This electric field strength E varies with power frequency AC. The power collection panel 21 in the inductive power collection circuit 2 is installed on the crossarm of the tower. If the height above the ground is h1, then the potential at the power collection panel 21 is U1 = Eh1, and it is consistent with the frequency of the power frequency grid voltage of the conductor. Through the connection of the power line 4 and the grounding wire 5, a power frequency AC source can be obtained between them. After rectification and three-terminal voltage regulation within the fault diagnosis circuit 125, power is supplied to the built-in voltage comparison and indicator light drive circuits. This power supply method is unaffected by light, temperature, altitude, and weather. It has a simple and reliable structure, is inexpensive, and can continuously provide power.

[0075] This invention detects and determines whether the arrester itself is deteriorating by detecting the voltage drop change of the built-in zinc oxide resistor proportional unit, solving the technical problem that this type of surge arrester cannot be monitored online. It draws power through spatial electric field induction on the metal plate surface, without any contact with conductors, ensuring safety and reliability. The power draw duration is unaffected by space, weather, or other factors, and requires no energy storage. It boasts advantages such as simple structure, uninterrupted power supply, and low cost, making it suitable for widespread application. Fault diagnosis consists of a simple voltage sampling and comparison circuit and LED indicator lights, requiring only a small number of electronic components. Cured with epoxy resin potting compound, it forms an integrated structure with the 10kV fixed external series gap zinc oxide surge arrester, offering advantages such as low price, accurate fault indication, and maintenance-free operation. This provides an economical and effective solution for the widespread application of online monitoring of 10kV fixed external series gap zinc oxide surge arresters.

[0076] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A fault identification method for a 10kV fixed external series gap surge arrester, characterized in that: The method employs a fault identification device, which includes an inductive power supply circuit, a voltage gradient detection circuit, and a fault identification circuit, wherein the fault identification circuit includes a fault diagnosis circuit and a fault indication module; the method includes: The inductive power-gathering circuit obtains system power by transforming induced charges through a power frequency AC electric field via spatial coupling, so as to provide working power for the fault diagnosis circuit and fault indication module. The voltage gradient detection circuit acquires the power frequency AC signal of the 10kV fixed external series gap surge arrester and converts the acquired power frequency AC signal into a DC level signal. The fault diagnosis circuit detects the DC level signal obtained by the voltage gradient detection circuit to determine whether the surge arrester has failed. The fault indication module issues an alarm indication signal when the fault diagnosis circuit detects a fault in the surge arrester. The input of the voltage gradient detection circuit is taken from a 10kV fixed external series gap surge arrester. The voltage gradient detection circuit includes a voltage sampling wire, a series composite jacket insulator insulation resistance, and several zinc oxide resistance plates. The voltage sampling wire is led out from the upper end of one zinc oxide resistance plate adjacent to the grounding terminal, and outputs a DC level signal after sampling.

2. The fault identification method for a 10kV fixed external series gap surge arrester according to claim 1, characterized in that: The inductive power collection circuit is a disc-shaped conductive plate, including a power collection disk and power collection terminals. The power collection disk is located below a 10kV overhead line, and the disk surface is parallel to the conductor. Through the transformation of the power frequency AC electric field, the electric field strength on the disk surface changes, and the induced charge from the changing field strength converges at the power collection terminals.

3. The fault identification method for a 10kV fixed external series gap surge arrester according to claim 2, characterized in that: The fault identification device also includes a power cord and a grounding wire. The power terminal is connected to one end of the power cord via a fastener, and the other end of the power cord is connected to the internal fault diagnosis circuit. One end of the grounding wire is connected to the earth, and the other end is connected to the internal fault diagnosis circuit.

4. The fault identification method for a 10kV fixed external series gap surge arrester according to claim 3, characterized in that: The 10kV fixed external series gap zinc oxide surge arrester includes a surge arrester body, on which the voltage gradient detection circuit and the fault identification circuit are installed.

5. The fault identification method for a 10kV fixed external series gap surge arrester according to claim 4, characterized in that: The fault identification circuit includes a cylindrical housing, a fault diagnosis circuit installed on the cylindrical housing, and a fault indication module. The fault indication module consists of indicator lights arranged symmetrically around the circumference of the cylindrical housing.

6. The fault identification method for a 10kV fixed external series gap surge arrester according to claim 5, characterized in that: The cylindrical shell is also provided with an inlet hole and an axial fixing hole. The inlet hole is used to pass through the power line and the grounding wire. The axial fixing hole is a through hole used to pass through the bottom bolt of the 10kV fixed external series gap zinc oxide surge arrester. The bottom bolt is fixed together as a whole by fasteners.

7. The fault identification method for a 10kV fixed external series gap surge arrester according to claim 3, characterized in that: The fault identification device also includes a rectifier circuit connected to the inductive power supply circuit. The fault diagnosis circuit has a built-in voltage comparison circuit and an indicator light driving circuit. The rectifier circuit is used to rectify the AC induced charge obtained from the power supply line from the power supply terminal of the power supply panel and the grounding wire from the ground, and then stabilize the output voltage as the power supply for the built-in voltage comparison circuit and the indicator light driving circuit.

8. A fault identification method for a 10kV fixed external series gap surge arrester according to claim 7, characterized in that: The voltage comparison circuit is used to compare the DC level signal output by the voltage gradient detection circuit with a given threshold and output a logic level signal to determine whether the integrated 10kV fixed external series gap surge arrester is in good condition; the indicator light driving circuit is used to amplify the received logic level signal and drive the fault indication module to issue an alarm indication signal.

Images