Checking method of overhead line fault indicator

Abstract

The invention provides a method for checking a fault indicator of an overhead line of a circuit, and the method comprises the steps: carrying out the configuration through adjusting the voltage in a voltage simulation loop and adjusting the current in a current simulation loop, obtaining a first working condition operation environment, and carrying out the detection to obtain a first working state of the fault indicator in the first working condition operation environment; by synchronously cutting off the voltage simulation loop and the current simulation loop, a second working condition operation environment is obtained through configuration, and the second working condition operation environment is used for simulating the working environment of the power overhead line when the grounding fault occurs; detecting to obtain a second working state of the fault indicator in a second working condition operation environment; and determining a ground fault checking result of the fault indicator based on the first working state and the second working state, wherein the ground fault checking result is checking success or checking failure. The problem that the checking scheme of the fault indicator in the prior art is high in cost is solved.

Description

Technical Field

[0001] The invention relates to the technical field of fault indicator calibration, and in particular to a calibration method for a circuit overhead line fault indicator. Background Art

[0002] At present, the common method for verifying the fault indicator of power overhead lines is to generate a simulated fault current through a large current generator to flow through the fault indicator, and the fault indicator makes a fault judgment based on the sampled fault current, or to verify the function of the fault indicator by simultaneously generating high voltage and high current through special instruments.

[0003] The method of calibrating and correcting the fault indicator using a large current generator has the problem that it cannot achieve a true simulation of the fault indicator's operating environment by simultaneously generating high voltage and large current (it cannot verify whether the high voltage has an impact on the fault indicator's function). At the same time, the verification of the transient current detection function of the fault indicator often requires a sudden change in current, but a large current generator is difficult to accurately achieve a sudden change in current. At the same time, frequent current sudden changes can easily cause damage to the large current generator.

[0004] Although the method of verifying the function of the fault indicator by simultaneously generating high voltage and high current through special instruments can simulate the actual operating conditions, the price of special instruments is very high, generally above one million, and it is difficult to promote in power grid companies.

[0005] With respect to the above-mentioned problems in the prior art, no effective solution has been proposed yet. Summary of the invention

[0006] The main purpose of the present invention is to provide a method for calibrating a fault indicator of an overhead circuit so as to solve the problem of high cost of the calibration scheme of the fault indicator in the prior art.

[0007] In order to achieve the above-mentioned purpose, according to one aspect of the present invention, a calibration method for an overhead line fault indicator of a circuit is provided, the calibration method comprising: configuring a first operating condition by adjusting the voltage in a voltage simulation loop and adjusting the current in a current simulation loop, wherein the voltage simulation loop and the current simulation loop are both arranged adjacent to the fault indicator, and the first operating condition operating environment is used to simulate the working environment when the operating parameters of the power overhead line are within a normal range, wherein the current simulation loop is constructed by a current transformer; detecting and obtaining a first working state of the fault indicator under the first operating condition, wherein the fault indicator is arranged adjacent to the voltage simulation loop and the current simulation loop; configuring a second operating condition by synchronously cutting off the voltage simulation loop and the current simulation loop, wherein the second operating condition operating environment is used to simulate the working environment of the overhead line when a ground fault occurs; detecting and obtaining a second working state of the fault indicator under the second operating condition; determining a ground fault calibration result of the fault indicator based on the first operating state and the second operating state, the ground fault calibration result being a calibration pass or a calibration fail.

[0008] Furthermore, by adjusting the voltage in the voltage simulation loop and adjusting the current in the current simulation loop, a first operating condition is configured, including: adjusting the voltage of the voltage simulation loop by controlling the voltage withstand tester; adjusting the primary current value of the primary side of the current transformer by adjusting the secondary current value of the secondary side of the current transformer, wherein the primary side is arranged adjacent to the fault indicator.

[0009] Furthermore, the voltage simulation loop and the current simulation loop are cut off synchronously, including: using a synchronizer to control a first switch on the voltage simulation loop and a second switch on the current simulation loop to be disconnected simultaneously.

[0010] Further, determining a ground fault verification result of the fault indicator based on the first working state and the second working state includes: in response to the first working state being a non-alarm state and the second working state being an alarm state, determining that the ground fault verification result is a verification pass.

[0011] Further, determining a ground fault verification result of the fault indicator based on the first working state and the second working state includes: in response to the first working state being an alarm state or the second working state being a non-alarm state, determining the ground fault verification result as a verification failure.

[0012] Furthermore, the verification method also includes: winding a single conductive wire bundle multiple times to obtain a test loop; electrically connecting one end of the test loop to the A-phase current output terminal of the relay protection tester, and electrically connecting the other end of the test loop to the N-phase current output terminal of the relay protection tester; placing a fault indicator on the test loop; configuring a third operating condition operating environment by controlling the output current value of the relay protection tester, and the third operating condition operating environment is used to simulate the working environment of the power overhead line when a phase-to-phase fault occurs; detecting a third working state of the fault indicator under the third operating state, and determining a phase-to-phase fault detection result of the fault indicator based on the third working state, and the phase-to-phase fault detection result is a verification pass or a verification fail.

[0013] Further, determining the interphase fault detection result of the fault indicator based on the third working state includes: in response to the third working state being an alarm state, determining the interphase fault verification result as verification passed.

[0014] Furthermore, placing the fault indicator on the test loop includes: arranging a plurality of fault indicators at intervals along the circumference of the test loop.

[0015] Further, placing the fault indicator on the test loop includes: placing the fault indicator on the test loop in a horizontal posture.

[0016] Furthermore, a single conductive wire bundle is wound multiple times to obtain a test loop, including: the coil wound multiple times is tied and fixed by insulating tape.

[0017] By applying the technical solution of the present invention, a first operating condition is obtained by configuring a voltage simulation loop and a current simulation loop, and a first working state of the fault indicator is detected. Also, the first operating condition is obtained by synchronously cutting off the voltage simulation loop and the current simulation loop, and a second working state of the fault indicator is detected, so that the fault indicator can be tested in the normal operating environment of the simulated overhead power line and in the fault working environment when a ground fault occurs in the overhead power line. In addition, during the verification process, due to the use of a solution in which the voltage and current loops are set separately and the current simulation loop is constructed by a current transformer, compared with the existing solution, environmental simulation under a comprehensive environment of different voltages and currents can be achieved without using expensive experimental equipment, thereby solving the problem of high cost of the fault indicator verification solution in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0019] Figure 1 A schematic flow chart showing an embodiment of a method for checking a circuit overhead line fault indicator according to the present invention is shown;

[0020] Figure 2 A schematic diagram of the architecture of an embodiment of an overhead line fault indicator test platform according to the present invention is shown;

[0021] Figure 3 A circuit wiring diagram of an embodiment of using a current transformer to generate a primary test current according to the present invention is shown;

[0022] Figure 4 A structural schematic diagram of an embodiment of a phase-to-phase line fault indicator testing device according to the present invention is shown. DETAILED DESCRIPTION

[0023] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0024] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0025] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the terms used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein, for example. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0026] Now, exemplary embodiments according to the present application will be described in more detail with reference to the accompanying drawings. However, these exemplary embodiments may be implemented in a variety of different forms and should not be construed as being limited to the embodiments described herein. It should be understood that these embodiments are provided to make the disclosure of the present application thorough and complete, and to fully convey the concepts of these exemplary embodiments to those of ordinary skill in the art. In the accompanying drawings, for the sake of clarity, the thickness of the layers and regions may be enlarged, and the same reference numerals are used to represent the same devices, and thus their descriptions will be omitted.

[0027] Combination Figures 1 to 4 As shown, according to a specific embodiment of the present application, a method for calibrating a circuit overhead line fault indicator is provided.

[0028] like Figure 1 As shown, the verification method of the circuit overhead line fault indicator includes the following implementation steps:

[0029] Step S10, configuring a first operating condition operating environment by adjusting the voltage in the voltage simulation loop and adjusting the current in the current simulation loop, wherein the voltage simulation loop and the current simulation loop are both arranged adjacent to the fault indicator, and the first operating condition operating environment is used to simulate the working environment when the operating parameters of the power overhead line are within a normal range, wherein the current simulation loop is constructed by a current transformer;

[0030] Step S20, detecting and obtaining the first working state of the fault indicator under the first operating condition, wherein the fault indicator is arranged adjacent to the voltage simulation circuit and the current simulation circuit; the purpose of the adjacent arrangement is that the magnetic sensing element (such as Hall sensor, magnetoresistor, etc.) in the fault indicator will detect the magnetic field of the above two circuits, and judge whether a large current flows according to the change of the magnetic field. In the power system, the fault indicator judges whether there is a current fault by sensing the change of the magnetic field around the wire.

[0031] In this way, even if the fault indicator is not directly connected to the high current, it can detect and respond to the high current by inducing the magnetic field, thereby verifying its performance under high current conditions. This test method avoids the possible damage to the indicator and test equipment caused by the direct use of high current, and can also provide a test environment that simulates real fault conditions.

[0032] Step S30, configuring a second operating condition by synchronously cutting off the voltage simulation loop and the current simulation loop, wherein the second operating condition is used to simulate the working environment of the power overhead line when a ground fault occurs;

[0033] Step S40, detecting and obtaining a second working state of the fault indicator under a second operating environment;

[0034] Step S50: determining a ground fault verification result of the fault indicator based on the first working state and the second working state, the ground fault verification result being verification pass or verification fail.

[0035] By applying the technical solution of the present application, a first operating condition is obtained by configuring a voltage simulation loop and a current simulation loop, and a first working state of the fault indicator is detected. Also, the first operating condition is obtained by synchronously cutting off the voltage simulation loop and the current simulation loop, and a second working state of the fault indicator is detected, so that the fault indicator can be tested in the normal operating environment of the simulated overhead power line and in the fault working environment when a ground fault occurs in the overhead power line. In addition, during the verification process, due to the use of a solution in which the voltage and current loops are set separately and the current simulation loop is constructed by a current transformer, compared with the existing solution, environmental simulation under a comprehensive environment of different voltages and currents can be achieved without using expensive experimental equipment, thereby solving the problem of high cost of the fault indicator verification solution in the prior art.

[0036] Compared with the prior art, the present invention provides a method for calibrating a fault indicator of an overhead power line. By using instruments commonly owned by power teams, the fault state of the overhead line can be accurately simulated, thereby achieving the purpose of quickly verifying the function of the fault indicator, which has great promotion significance.

[0037] Phase-to-phase fault detection and ground fault detection are two main types of power system fault detection. They are used to detect power system faults of different natures, as follows:

[0038] Phase-to-phase fault detection: Phase-to-phase fault refers to a direct or indirect short-circuit fault between two or three phases in a power system. This type of fault will cause a drop in voltage and a sharp rise in current between phases. In overhead power lines, phase-to-phase faults may be caused by branches, birds, foreign objects, etc. crossing two phase conductors. In phase-to-phase fault detection, the fault indicator needs to be able to identify and indicate a short-circuit fault between two or three phases, usually by detecting sudden changes and phase differences in the fault current.

[0039] Ground fault detection: A ground fault refers to a direct or indirect short circuit fault between a phase or neutral point in a power system and the earth. This type of fault will cause the voltage of the fault phase to drop, the voltage of the non-fault phase to increase, and current to flow to the earth. Ground faults may be caused by insulation damage to the conductor to the ground, lightning strikes, etc. In ground fault detection, the fault indicator needs to be able to identify and indicate a short circuit fault between a phase and the earth, usually by detecting the increase of single-phase current, the drop of voltage, and possible zero-sequence current.

[0040] In the fault detection of overhead lines, phase-to-phase faults and ground faults are the two most common fault types, which require different detection technologies and methods to identify and locate. Therefore, the fault indicator calibration method is usually divided into two parts: phase-to-phase fault detection and ground fault detection to ensure that the fault indicator can accurately indicate different types of faults.

[0041] In an optional embodiment, in order to truly reflect the ground fault (only single-phase fault current), avoid the influence of the reverse current on the adjacent phase side on the test, and introduce voltage criteria, a test platform is built through a current transformer for this ground test.

[0042] The test platform adds current to the secondary side of the current transformer through the current transformer comprehensive tester, and the primary side induces a large current as the test current. Due to the good insulation and sealing of epoxy resin insulation casting, and the binding effect of the internal iron core on the magnetic field, the magnetic field generated by the internal primary conductor is basically bound in the transformer body, and will not have a large magnetic field effect on the external primary current conductor. Therefore, the method of applying primary current through the current transformer can more accurately measure the current mutation amount of the overhead line fault indicator action reversal, avoiding the influence of adjacent phase current.

[0043] In the field of power system fault detection, "action flip" usually refers to the state change of the fault indicator from normal to alarm when a fault is detected. In the fault indicator of the overhead line, this state change may be manifested as the indicator light on the indicator changing from off to on, or a mechanical part in the indicator moving from one position to another to indicate the occurrence of a fault. The magnitude of the current mutation of the action flip refers to the amount of current change required to trigger this state change, which is a key indicator for measuring the sensitivity and accuracy of the fault indicator.

[0044] In the ground short-circuit fault test, the action reversal needs to occur when the induced current on the primary side reaches a certain mutation amount. By applying the primary current through the current transformer, this mutation amount can be more accurately controlled and measured to ensure that the fault indicator can accurately make a reversal action under the simulated fault conditions, that is, switch from the normal state to the fault indication state. This helps to verify and optimize the performance of the fault indicator and ensure that it can detect and indicate ground faults in a timely and accurate manner in the actual power system.

[0045] Before the test, the normal operating voltage is simulated by the voltage withstand tester, and the normal operating current is simulated by the current transformer comprehensive tester. When simulating a fault, the sudden increase of fault current and the sudden drop of fault voltage are simulated by synchronously cutting off the voltage simulation circuit and the parallel CT circuit.

[0046] On overhead lines, three-phase currents usually flow simultaneously with phase differences. If a large current is applied directly to one conductor for testing, the magnetic field generated by the current in the adjacent conductor may affect the measurement of the fault indicator. The core and epoxy resin insulation casting of the current transformer can confine the magnetic field generated by the primary current to the inside of the transformer, so that even if there is a reverse current in the adjacent conductor, it will not interfere with the current transformer and fault indicator under test, ensuring the accuracy of the test results.

[0047] When an overhead line fails, the current will change suddenly, and this change is crucial for the triggering of the fault indicator. Traditional testing methods may find it difficult to accurately simulate this current change, but by applying secondary current through the current transformer and cutting off the parallel current transformer loop, the current change can be more finely controlled, the current change can be simulated, and the fault indicator's response to the current change can be tested more accurately.

[0048] Optionally, configuring to obtain a first operating condition by adjusting a voltage in a voltage simulation loop and adjusting a current in a current simulation loop includes:

[0049] By controlling the withstand voltage tester to adjust the voltage of the voltage simulation circuit;

[0050] The primary current value of the primary side of the current transformer is adjusted by adjusting the secondary current value of the secondary side of the current transformer, wherein the primary side is arranged adjacent to the fault indicator.

[0051] A current transformer (CT) is a device used to measure alternating current. Its working principle is based on the law of electromagnetic induction, specifically Faraday's law of electromagnetic induction. It converts a high current (primary current) into a proportionally lower current (secondary current) for easy measurement and control.

[0052] Working principle of current transformer: The current transformer consists of two coils wound on the same core, one is the primary coil (Primary Winding) and the other is the secondary coil (Secondary Winding). The primary coil usually has only a few turns or even a single turn, while the secondary coil has more turns. When the load current passes through the primary side, an alternating magnetic field is generated around the core. This alternating magnetic field induces an electromotive force in the secondary coil, thereby generating a secondary current. The secondary current is proportional to the primary current, and the ratio depends on the turns ratio of the coil. Figure 2 Two parallel-connected sensing coils CT1 and CT2 are shown.

[0053] Primary side: This is the output end of the current transformer, which is directly connected to the circuit being measured. The current flowing through the primary side is the large current in the actual line, such as the current of the power overhead line.

[0054] Secondary: This is the input side of the current transformer, where a smaller current proportional to the primary current is fed in. The secondary side is usually connected to a measuring instrument, relay, or protection device to safely measure and control the current.

[0055] In power systems, the use of current transformers can protect measuring instruments from direct impact of high currents, and can also achieve remote measurement and monitoring of current in power systems. The turns ratio between the primary and secondary sides of the current transformer is designed according to actual needs and is usually given in the specification of the current transformer.

[0056] In the ground short circuit fault test, the current transformer is used to simulate the large current on the primary side, and the change of the primary current is indirectly controlled and measured by applying current on the secondary side. This method can avoid direct damage to the test equipment and accurately simulate the fault condition. At the same time, the insulation performance and magnetic field binding characteristics of the current transformer can ensure the safety of the test process, avoid the interference of adjacent phase current, and make the fault indicator test more accurate and reliable.

[0057] The working principle of the current transformer is based on the law of electromagnetic induction. It consists of a primary coil and a secondary coil, which are wound on the same iron core. When current passes through the primary coil, a magnetic field is generated in the iron core, which in turn induces an electromotive force in the secondary coil, thereby generating current. According to the law of electromagnetic induction, the secondary current is proportional to the primary current, and the ratio depends on the turns ratio of the primary and secondary coils. The material of the iron core (usually a ferromagnetic material with high magnetic permeability) enhances the induction effect of the magnetic field, while also limiting the diffusion of the magnetic field, minimizing the impact of external current on the test platform.

[0058] The epoxy resin insulated current transformer has good insulation and sealing properties, which can prevent external current and electromagnetic interference, ensuring the accuracy of the test. The iron core not only enhances the magnetic field induction, but also limits the diffusion of the magnetic field, so that the magnetic field generated by the primary current of the current transformer is basically confined to the inside of the transformer, and will not have a significant magnetic field effect on the adjacent phase current conductor, thereby avoiding the influence of the reverse current on the adjacent phase side on the test.

[0059] Optionally, by synchronously cutting off the voltage simulation loop and the current simulation loop, comprising:

[0060] A synchronizer is used to control the first switch on the voltage simulation loop and the second switch on the current simulation loop to be opened simultaneously.

[0061] The steps for simulating the normal operating state (i.e. the first operating condition) are as follows: before the test, a withstand voltage tester is used to simulate the normal operating voltage of the power overhead line, and a current transformer comprehensive tester is used to simulate the normal operating current to ensure that the test platform can truly reflect the normal operating conditions of the power system.

[0062] The steps of simulating fault conditions (i.e., the second operating condition) are as follows: In order to simulate a ground short circuit fault, the test platform needs to achieve a sudden increase in fault current and a sudden drop in fault voltage by synchronously removing the voltage simulation circuit and the parallel CT circuit. The specific operation is that when simulating the fault condition, the voltage simulation circuit and the parallel CT circuit are removed at the same time, which will cause a sudden increase in the primary side current (simulating the fault current) and a sudden drop in voltage (simulating the fault voltage), thereby simulating the actual situation of the ground fault.

[0063] Through this series of operations, the current transformer test platform can provide an accurate test environment for the overhead line fault indicator to verify its performance under ground short circuit faults. At the same time, by controlling the current and voltage, various fault conditions can be simulated to ensure the comprehensiveness and reliability of the test.

[0064] Optionally, determining a ground fault verification result of the fault indicator based on the first working state and the second working state includes:

[0065] In response to the first working state being a no-alarm state and the second working state being an alarm state, it is determined that the ground fault verification result is a verification pass.

[0066] Optionally, determining a ground fault verification result of the fault indicator based on the first working state and the second working state includes:

[0067] In response to the first working state being an alarm state or the second working state being a non-alarm state, it is determined that the ground fault verification result is a verification failure.

[0068] Optionally, the verification method further includes:

[0069] Winding a single conductive wire bundle multiple times to obtain a test loop;

[0070] Electrically connect one end of the test loop to the A-phase current output terminal of the relay protection tester, and electrically connect the other end of the test loop to the N-phase current output terminal of the relay protection tester;

[0071] Place the fault indicator on the test loop; according to the principle of electromagnetics, a magnetic field will be generated when current passes through a wire. The current in multiple turns of wire in the test line loop will form a magnetic field, and a stronger magnetic field will be formed by the superposition of multiple magnetic fields.

[0072] By controlling the output current value of the relay protection tester, a third operating condition is configured to obtain the operating environment, which is used to simulate the working environment of the power overhead line when a phase-to-phase fault occurs;

[0073] A third working state of the fault indicator under a third operating condition is detected, and a phase-to-phase fault detection result of the fault indicator is determined based on the third working state, the phase-to-phase fault detection result being a verification pass or a verification fail.

[0074] The test loop can simulate the high current conditions that the power equipment may encounter in actual operation without damaging the test equipment. In the power overhead line fault indicator calibration method of the present application, the main functions of the test loop are as follows:

[0075] 1. Make full use of the current amplification effect: When the current passes through the wire in the loop, according to Ampere's loop law, a magnetic field will be formed inside the loop. If the loop is composed of multiple turns of wire, the magnetic field generated by each turn of wire will be superimposed, thereby generating an enhanced magnetic field in the center of the loop. This enhanced magnetic field can cause the current passing through the loop to form an electromagnetic effect equivalent to a larger current at the detection end of the fault indicator, thereby testing the response of the fault indicator under large current.

[0076] 2. Achieve precise control: Using a relay (relay protection tester) can generate and control simulated current. By adjusting the output of the relay, the size and waveform of the test current can be accurately set to simulate various fault conditions. In the test loop, the current addition of the relay can be amplified, which makes it possible to test high current fault indicators even with a relatively small current generator.

[0077] 3. Simulate real fault conditions: In actual power systems, phase-to-phase short circuit faults and ground faults will generate large currents, which will trigger the alarm or indication function of the fault indicator. Through the cooperation of the test loop and the relay protection instrument, these real fault conditions can be simulated to test the sensitivity, accuracy and reliability of the fault indicator.

[0078] 4. Protect test equipment: Directly using a high current generator to apply a high current to the power equipment for testing may cause damage to the test equipment. By building a test loop, the magnetic field effect can be used to achieve the test purpose without introducing excessive current to the test line or fault indicator, thereby protecting the test equipment.

[0079] In summary, by utilizing the smaller current generated by the protection relay and the magnetic field effect formed by multiple turns of the wire in the test loop, the electromagnetic environment of a large current can be simulated at the detection point of the fault indicator. The precise control of the magnitude, waveform, and sudden change of this current is achieved through the protection relay, and the entire process is safe and repeatable.

[0080] In an optional embodiment, the technical solution of the present application is adopted to provide a calibration method for overhead line fault indicators, which is mainly divided into two aspects: detailed fault detection and ground fault detection. The instruments used are all commonly used instruments by power grid companies and have strong promotion benefits and economy.

[0081] The method for phase-to-phase short circuit fault testing includes the following steps:

[0082] 1. Use a single test line to wind 14 turns to form a test loop, fix it with insulating tape, and connect the two ends of the test line to the A and N phase current output terminals of the relay protection instrument. Place the fault indicator horizontally on the test line, as shown in the figure below:

[0083] 2. During the test, the current of the relay is increased and the magnetic field of the same-direction current in the test loop is amplified to achieve simulation and precise control of large current. The relay can be a relay protection tester, which can output precisely controlled currents, which form a closed loop through multiple turns of the test wire.

[0084] Optionally, determining a phase-to-phase fault detection result of the fault indicator based on the third working state includes:

[0085] In response to the third working state being the alarm state, it is determined that the phase-to-phase fault verification result is a verification pass.

[0086] Optionally, placing the fault indicator on the test loop includes: arranging a plurality of fault indicators at intervals along the circumference of the test loop.

[0087] like Figure 4 As shown, optionally, placing the fault indicator on the test loop includes: placing the fault indicator on the test loop in a horizontal posture.

[0088] Fault indicators are usually designed to detect changes in the magnetic field caused by current in three-dimensional space. Horizontal placement ensures that the fault indicator is located at the center of the magnetic field formed by the test line loop, so that it can receive the evenly distributed magnetic field around the loop, thereby improving the accuracy and stability of detection.

[0089] Fault indicators in overhead power lines are also usually installed horizontally. This placement can more realistically simulate the working environment and status of the fault indicators under actual installation conditions, ensuring that the test results are closer to actual operating conditions.

[0090] Horizontal placement can reduce the effect of gravity on the internal components of the fault indicator, especially for those indicators based on magnetic sensing elements. Gravity may cause the magnetic sensing elements to shift, thus affecting the accuracy of the detection results.

[0091] like Figure 4 As shown, optionally, a single conductive wire bundle is wound multiple times to obtain a test loop, including: the coil wound multiple times is tied and fixed by insulating tape.

[0092] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects:

[0093] 1. In terms of simulating phase-to-phase faults, a single test wire is used to form a test loop, and a large current is accurately applied through a relay. When the simulated switch cuts off the fault, it only needs to stop the relay, which will not cause damage to the instrument.

[0094] 2. In terms of simulating ground faults, power is supplied to the primary circuit through the secondary circuit of the current transformer, which avoids the influence of magnetic field neutralization caused by current circulation and the test results. At the same time, the actual situation of the ground fault can be well simulated through the synchronous cooperation of the withstand voltage tester and the current transformer tester.

[0095] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0096] In addition to the above, it should be noted that "one embodiment", "another embodiment", "embodiment", etc. mentioned in this specification refer to the specific features, structures or characteristics described in conjunction with the embodiment included in at least one embodiment generally described in this application. The same expression appearing in multiple places in the specification does not necessarily refer to the same embodiment. Further, when describing a specific feature, structure or characteristic in conjunction with any embodiment, it is claimed that the realization of such feature, structure or characteristic in conjunction with other embodiments also falls within the scope of the present invention.

[0097] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0098] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for calibrating a circuit overhead line fault indicator, characterized in that: The verification method comprises: A first operating condition is configured by adjusting the voltage in the voltage simulation loop and adjusting the current in the current simulation loop, wherein the voltage simulation loop and the current simulation loop are both arranged adjacent to the fault indicator, and the first operating condition is used to simulate the working environment when the operating parameters of the power overhead line are within a normal range, wherein the current simulation loop is constructed by a current transformer; Detecting and obtaining a first working state of a fault indicator under a first operating condition, wherein the fault indicator is arranged adjacent to the voltage simulation circuit and the current simulation circuit; A second operating condition is configured by synchronously cutting off the voltage simulation loop and the current simulation loop, wherein the second operating condition is used to simulate the working environment of the power overhead line when a ground fault occurs; Detecting and obtaining a second working state of the fault indicator under a second operating condition; A ground fault verification result of the fault indicator is determined based on the first working state and the second working state, and the ground fault verification result is verification pass or verification fail.

2. The method for verifying an overhead line fault indicator according to claim 1, characterized in that: By adjusting the voltage in the voltage simulation loop and adjusting the current in the current simulation loop, a first operating condition operating environment is configured, including: By controlling the withstand voltage tester to adjust the voltage of the voltage simulation circuit; The primary current value of the primary side of the current transformer is adjusted by adjusting the secondary current value of the secondary side of the current transformer, wherein the primary side is arranged adjacent to the fault indicator.

3. The method for verifying an overhead line fault indicator according to claim 1, characterized in that: By synchronously cutting off the voltage simulation loop and the current simulation loop, comprising: A synchronizer is used to control the first switch on the voltage simulation loop and the second switch on the current simulation loop to be disconnected at the same time.

4. The method for verifying an overhead line fault indicator according to claim 1, characterized in that: Determining a ground fault verification result of the fault indicator based on the first working state and the second working state includes: In response to the first working state being a no-alarm state and the second working state being an alarm state, it is determined that the ground fault verification result is a verification pass.

5. The method for calibrating a circuit overhead line fault indicator according to claim 1, characterized in that: Determining a ground fault verification result of the fault indicator based on the first working state and the second working state includes: In response to the first working state being an alarm state or the second working state being a non-alarm state, it is determined that the ground fault verification result is a verification failure.

6. The method for calibrating a circuit overhead line fault indicator according to claim 1, characterized in that: The verification method also includes: Winding a single conductive wire bundle multiple times to obtain a test loop; Electrically connect one end of the test loop to the A-phase current output terminal of the relay protection tester, and electrically connect the other end of the test loop to the N-phase current output terminal of the relay protection tester; Place the fault indicator on the test loop; By controlling the output current value of the relay protection tester, a third operating condition operating environment is configured, wherein the third operating condition operating environment is used to simulate the working environment of the power overhead line when a phase-to-phase fault occurs; The third working state of the fault indicator under the third operating condition is detected, and a phase-to-phase fault detection result of the fault indicator is determined based on the third working state, wherein the phase-to-phase fault detection result is a verification pass or a verification fail.

7. The method for verifying an overhead line fault indicator according to claim 6, characterized in that: Determining a phase-to-phase fault detection result of the fault indicator based on the third working state includes: In response to the third working state being an alarm state, it is determined that the interphase fault verification result is a verification pass.

8. The method for calibrating an overhead line fault indicator according to claim 6, characterized in that: Placing the fault indicator on the test loop includes: arranging a plurality of the fault indicators at intervals along the circumference of the test loop.

9. The method for calibrating an overhead line fault indicator according to claim 6, characterized in that: Placing the fault indicator on the test loop includes: placing the fault indicator on the test loop in a horizontal posture.

10. The method for verifying an overhead line fault indicator according to claim 6, characterized in that: A single conductive wire bundle is wound multiple times to obtain a test loop, including: the coil wound multiple times is tied and fixed by insulating tape.

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