Calibration Method of Overhead Power Line Fault Indicator

Abstract

The invention provides a method for calibrating a fault indicator for an overhead power line. The calibration method includes: configuring a first operating environment by adjusting the voltage in a voltage simulation loop and the current in a current simulation loop, and detecting a first working state of the fault indicator under the first operating environment; configuring a second operating environment by synchronously cutting off the voltage simulation loop and the current simulation loop, wherein the second operating environment is used to simulate the working environment of the overhead power line when a ground fault occurs; detecting a second working state of the fault indicator under the second operating environment; and determining a ground fault calibration result of the fault indicator based on the first and second operating states, wherein the ground fault calibration result is either a calibration pass or a calibration fail. This application solves the problem of high cost of fault indicator calibration solutions in the prior art.

Description

Technical Field

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

[0002] Currently, the common method for calibrating fault indicators for power overhead lines is to generate a simulated fault current through the fault indicator using a large current generator, 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 generating high voltage and large current at the same time (it cannot be verified whether the high voltage affects the fault indicator 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 it is difficult for a large current generator 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 large current through special instruments can simulate the actual operating conditions, the price of special instruments is very high, generally over one million yuan, making it 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 power line, 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 power line fault indicator 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 overhead power line are within a normal range; 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 when a ground fault occurs in the overhead power line; 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 working state and the second working 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 turned off 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 no-alarm state and the second working state being an alarm state, determining the ground fault verification result as passed.

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

[0016] Furthermore, the single conductive wire bundle is wound multiple times to obtain a test loop, including: binding and fixing the coil after the multiple turns 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. Furthermore, the first operating condition is obtained by synchronously disconnecting 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 power overhead line and the fault working environment when a ground fault occurs in the power overhead line. In addition, during the verification process, due to the adoption 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 the use of expensive experimental equipment, thereby solving the problem of high cost of the fault indicator verification solution in the existing technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

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

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

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

[0022] Figure 4 A schematic structural 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 of the embodiments in this 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, they indicate 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 are interchangeable where appropriate, so that the embodiments of the present application described herein can, for example, be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof 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 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 can be implemented in a variety of different forms and should not be interpreted as being limited to the embodiments described herein. It should be understood that these embodiments are provided to make the disclosure of this 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 layers and regions may be exaggerated, and the same reference numerals are used to represent the same devices, and thus their descriptions will be omitted.

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

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

[0029] Step S10: configuring a first operating environment by adjusting the voltage in the voltage simulation loop and the current in the current simulation loop, wherein the voltage simulation loop and the current simulation loop are both provided adjacent to the fault indicator, and the first operating environment is used to simulate an operating environment when 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 detects the fault indicator's first operating state under the first operating condition. The fault indicator is positioned adjacent to both the voltage simulation circuit and the current simulation circuit. This placement allows the magnetic sensing element (such as a Hall effect sensor or magnetoresistor) in the fault indicator to detect the magnetic fields of both circuits and determine whether a high current is flowing based on changes in the magnetic fields. In power systems, fault indicators detect current faults by sensing changes in the magnetic field surrounding a conductor.

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

[0032] Step S30, configuring a second operating environment by synchronously cutting off the voltage simulation loop and the current simulation loop;

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

[0034] Step S50 : determining a ground fault calibration result of the fault indicator based on the first working state and the second working state, where the ground fault calibration result is calibration pass or calibration 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. Furthermore, 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 power overhead line and the fault working environment when a ground fault occurs in the power overhead line. In addition, during the verification process, due to the adoption 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 the use of expensive experimental equipment, thereby solving the problem of high cost of the fault indicator verification solution in the existing technology.

[0036] Compared with the existing technology, the present invention provides a method for calibrating the fault indicator of an overhead power line. By using instruments and meters commonly owned by power teams, the fault state of the overhead line can be accurately simulated, thereby achieving the purpose of quickly testing 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: A phase-to-phase fault is a direct or indirect short circuit between two or three phases in a power system. This fault causes a voltage drop and a sharp current increase between phases. In overhead power lines, phase-to-phase faults can be caused by branches, birds, or foreign objects crossing between two phase conductors. For phase-to-phase fault detection, a fault indicator must be able to identify and indicate short circuits between two or three phases. This is typically achieved by detecting sudden changes in the fault current and phase differences.

[0039] Ground Fault Detection: A ground fault is a direct or indirect short circuit between a phase or neutral point in a power system and the ground. This fault causes a voltage drop between the fault phase and the ground, an increase between the fault phase and the ground, and a current to flow to the ground. Ground faults can be caused by insulation damage to the conductor or lightning strikes. For ground fault detection, a fault indicator must be able to identify and indicate a short circuit between a phase and the ground. This is typically achieved by detecting a single-phase current increase, voltage drop, and possible zero-sequence current.

[0040] Phase-to-phase faults and ground faults are the two most common fault types in overhead line fault detection, requiring different detection technologies and methods to identify and locate them. Therefore, fault indicator calibration methods are typically divided into two parts: phase-to-phase fault detection and ground fault detection. This ensures that the fault indicator accurately indicates different types of faults.

[0041] In an optional embodiment, in order to truly reflect the ground fault (only single-phase fault current), avoid the impact of reverse current on the adjacent phase side on the test, and introduce voltage criterion, this ground test builds a test platform through current transformers.

[0042] This test platform applies current to the secondary side of the current transformer using a current transformer integrated tester, inducing a high current on the primary side as the test current. Due to the excellent insulation and sealing properties of the epoxy resin casting, and the magnetic field-binding effect of the internal iron core, the magnetic field generated by the internal primary conductor is essentially confined within the transformer itself, without significantly affecting the external primary current conductor. Therefore, applying primary current through the current transformer allows for more accurate measurement of the magnitude of the current surge that triggers the reversal of the overhead line fault indicator, avoiding the influence of adjacent phase currents.

[0043] In the field of power system fault detection, "flip" typically refers to the state transition of a fault indicator from normal to alarm upon detecting a fault. In overhead line fault indicators, this state transition might manifest as an indicator light turning off and then on, or a mechanical component moving from one position to another, indicating the occurrence of a fault. The magnitude of the current change required to trigger this state transition is a key indicator of the sensitivity and accuracy of a fault indicator.

[0044] In ground short-circuit fault testing, reversal must occur when the primary-side induced current reaches a certain sudden change. By applying the primary current through a current transformer, this sudden change can be more precisely controlled and measured, ensuring that the fault indicator accurately switches from normal to fault-indicating state under simulated fault conditions. This helps verify and optimize the performance of the fault indicator, ensuring its timely and accurate detection and indication of ground faults in actual power systems.

[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 in fault current and the sudden drop in fault voltage are simulated by synchronously cutting off the voltage simulation circuit and the parallel CT circuit.

[0046] On overhead lines, three-phase current typically flows simultaneously, but out of phase. Applying a high current directly to a single conductor for testing can affect the fault indicator's measurement due to the magnetic field generated by the current in the adjacent conductor. The current transformer's core and epoxy resin insulation confine the magnetic field generated by the primary current to the transformer itself. This prevents interference with the current transformer and fault indicator under test, even if reverse current flows in adjacent conductors, ensuring accurate test results.

[0047] When an overhead line fault occurs, the current experiences a sudden change, and this change is crucial for triggering the fault indicator. Traditional testing methods can struggle to accurately simulate this sudden change. However, applying secondary current through a current transformer and disconnecting the parallel current transformer circuit allows for more precise control of the current change, simulating the magnitude of the sudden change, and thus more accurately testing the fault indicator's response to this sudden change.

[0048] Optionally, configuring a first operating condition by adjusting the voltage in the voltage simulation loop and adjusting the current in the 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 operating 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 easier measurement and control.

[0052] Working Principle of a Current Transformer: A current transformer consists of two coils wound around a common core: a primary coil and a secondary coil. The primary coil typically has only a few turns, or even a single turn, while the secondary coil has more turns. When load current flows through the primary coil, an alternating magnetic field is generated around the core. This alternating magnetic field induces an electromotive force in the secondary coil, generating a secondary current. The secondary current is proportional to the primary current, with the ratio determined by the turns ratio of the coils. Figure 2 Two parallel-connected sensing coils CT1 and CT2 are shown in FIG.

[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 overhead power line.

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

[0055] In power systems, current transformers protect measuring instruments from direct impacts of high currents and enable remote current measurement and monitoring within power systems. The turns ratio between the primary and secondary sides of a current transformer is designed based on actual needs and is typically specified in the current transformer's specification sheet.

[0056] During ground fault testing, current transformers are used to simulate high currents on the primary side. By applying current to the secondary side, changes in the primary current are indirectly controlled and measured. This method avoids direct damage to the test equipment and accurately simulates fault conditions. Furthermore, the current transformer's insulation and magnetic field confinement properties ensure safety during testing, preventing interference from adjacent phase currents and making fault indicator testing more accurate and reliable.

[0057] The operating principle of a current transformer is based on the law of electromagnetic induction. It consists of a primary coil and a secondary coil, both wound around a common iron core. When current flows through the primary coil, it generates a magnetic field in the iron core. This field, in turn, induces an electromotive force in the secondary coil, generating a current. According to the law of electromagnetic induction, the secondary current is proportional to the primary current, with the ratio determined by the turns ratio between the primary and secondary coils. The core material (typically a ferromagnetic material with high magnetic permeability) enhances the induction effect of the magnetic field while also limiting its diffusion, minimizing the impact of external currents on the test platform.

[0058] Epoxy resin-infused current transformers offer excellent insulation and sealing properties, preventing external currents and electromagnetic interference, ensuring test accuracy. The iron core not only enhances magnetic field induction but also limits its diffusion, keeping the magnetic field generated by the primary current of the current transformer essentially confined to the transformer itself. This prevents significant magnetic field effects on adjacent phase current conductors, thus preventing the impact of reverse current on the adjacent phase.

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

[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 disconnected at the same time.

[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] To simulate a fault condition (also known as the second operating environment), the test platform simulates a ground fault by simultaneously disconnecting the voltage simulation circuit and the shunt CT circuit to produce a sudden increase in fault current and a sudden drop in fault voltage. Specifically, when simulating a fault condition, the voltage simulation circuit and the shunt CT circuit are disconnected simultaneously. This causes a sudden increase in primary current (simulating the fault current) and a sudden drop in voltage (simulating the fault voltage), simulating a ground fault.

[0063] Through this series of operations, the current transformer test platform can provide an accurate test environment for overhead line fault indicators to verify their performance under ground short-circuit faults. At the same time, by controlling 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 passed verification.

[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] Wind 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, when current passes through a wire, a magnetic field is generated. The current of multiple turns of wire in the test line loop will form a magnetic field, and the superposition of multiple magnetic fields will form a stronger magnetic field.

[0072] By controlling the output current value of the relay protection tester, a third operating condition is configured 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, where the phase-to-phase fault detection result is a check pass or a check 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 this application, the main functions of the test loop are as follows:

[0075] 1. Leverage the current amplification effect: When current passes through a conductor in a loop, Ampere's loop law generates a magnetic field within the loop. If the loop consists of multiple turns of wire, the magnetic fields generated by each turn are superimposed, resulting in an enhanced magnetic field at the center of the loop. This enhanced magnetic field causes the current passing through the loop to create an electromagnetic effect at the fault indicator's detection end equivalent to a larger current, thereby testing the fault indicator's response to high currents.

[0076] 2. Achieve precise control: Using a relay (relay protection tester) can generate and control simulated current. By adjusting the relay output, the magnitude and waveform of the test current can be precisely set to simulate various fault conditions. In the test loop, the relay current addition can be amplified, making 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 circuits and ground faults generate high currents, which can trigger the alarm or indication function of the fault indicator. By combining the test loop and the relay, these real fault conditions can be simulated to test the sensitivity, accuracy, and reliability of the fault indicator.

[0078] 4. Protecting test equipment: Directly applying high current to power equipment using a high-current generator for testing may damage the test equipment. However, by constructing a test loop, the magnetic field effect can be used to achieve the test purpose without introducing excessive current into the test line or fault indicator, thus protecting the test equipment.

[0079] In summary, by utilizing the smaller current generated by the relay and the magnetic field effect formed by multiple turns of the wire in the test loop, a large current electromagnetic environment 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 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 grounding 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 testing a phase-to-phase short circuit fault includes the following steps:

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

[0083] 2. During the test, the current of the relay is increased and the magnetic field of the test loop is amplified by the current in the same direction, achieving simulation and precise control of large currents. The relay can be a relay protection tester, which can output precisely controlled currents. These currents form a closed loop through multiple turns of 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 inter-phase fault verification result is verification passed.

[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 typically designed to detect changes in the magnetic field caused by current flow in three dimensions. Horizontal placement ensures the fault indicator is centered in the magnetic field formed by the test wire loop. This allows it to receive a uniformly distributed magnetic field from all sides of the loop, improving detection accuracy and stability.

[0089] Fault indicators in overhead power lines are usually installed horizontally. This placement can more realistically simulate the working environment and status of the fault indicator 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 those based on magnetic sensing elements. Gravity may cause the magnetic sensing elements to shift, thereby 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: binding and fixing the coil after the multiple turns 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 test loop is formed by winding a single test wire, and a large current is accurately applied through a relay. When the simulated switch cuts off the fault, it is only necessary to stop the relay, which will not cause damage to the instrument.

[0094] 2. In terms of simulating ground faults, by using the secondary circuit of the current transformer to supply power to the primary circuit, the magnetic field neutralization caused by the current circulation is avoided to affect the test results. At the same time, the synchronous cooperation of the withstand voltage tester and the current transformer tester can well simulate the actual situation of the ground fault.

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

[0096] In addition to the above, it should be noted that references to "one embodiment," "another embodiment," "an embodiment," and the like in this specification refer to specific features, structures, or characteristics described in conjunction with that embodiment as included in at least one embodiment generally described in this application. The appearance of the same expression in multiple places in the specification does not necessarily refer to the same embodiment. Furthermore, when a specific feature, structure, or characteristic is described in conjunction with any embodiment, it is intended that such feature, structure, or characteristic, when implemented 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 focus. 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 foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

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

2. The method for calibrating a power overhead line fault indicator according to claim 1, characterized in that: By adjusting the voltage in the voltage simulation loop and the current in the current simulation loop, a first operating condition 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 calibrating a power overhead line fault indicator according to claim 1, wherein: 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 calibrating a power overhead line fault indicator according to claim 1, wherein: 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 passed verification.

5. The method for calibrating a power overhead line fault indicator according to claim 1, wherein: 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 power overhead line fault indicator according to claim 1, characterized in that: The verification method further comprises: Wind 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 is configured to simulate the working environment of the power overhead line when a phase-to-phase fault occurs; A 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, where the phase-to-phase fault detection result is a check pass or a check fail.

7. The method for calibrating a power 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 inter-phase fault verification result is a verification pass.

8. The method for calibrating a power overhead line fault indicator according to claim 6, wherein: 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 a power overhead line fault indicator according to claim 6, wherein: 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 calibrating a power 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: binding and fixing the coil after the multiple turns with insulating tape.

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