A current transformer secondary circuit calibration method and system

Abstract

The application discloses a current transformer secondary circuit line checking method and system, and the method comprises the following steps: acquiring transformer secondary circuit wiring information, configuring a transformer secondary circuit line checking module according to the transformer secondary circuit wiring information; checking the wiring condition of the secondary circuit line checking module; identifying the wiring error type through the response of the secondary circuit line checking module in the case of wiring error, and correcting the wiring error type correspondingly, so that the line checking time is short, and the line checking accuracy is high.

Description

Technical Field

[0001] This invention relates to the field of power system automation testing technology, and in particular to a method and system for calibrating the secondary circuit of a current transformer. Background Technology

[0002] The taps of the current transformer's terminal box and the terminals of the terminal box must correspond one-to-one according to the substation standard design requirements. Wiring errors can lead to open circuits in the current loop or incorrect winding usage, and in severe cases, protection systems may fail to operate or malfunction, seriously affecting the safe and stable operation of the power grid. The secondary circuit calibration of current transformers is one of the important acceptance procedures for new or renovated substation projects. Electromagnetic current transformers are found in almost all operating substations. For the secondary circuit acceptance of electromagnetic current transformers, there are two common methods for CT secondary circuit calibration. One is the primary current-increasing method. This method requires directly applying a large current to the primary equipment and verifying the secondary circuit cables by measuring the correctness of the secondary current. This method requires large, heavy, and expensive specialized equipment, and the process is complex and time-consuming. For construction units, some units lack the necessary current-increasing capabilities and qualifications. For acceptance units, this method is time-consuming and labor-intensive, and in some areas, the power grid often does not use this method. Another method for CT secondary circuit calibration is to test the continuity to ground using a multimeter. This method requires two people to work together. First, all the cables to be checked are removed, and then the wiring is checked by checking the continuity of the grounding at both ends. However, this method has the problem of slow wiring speed and easy to reconnect incorrectly when restoring the wiring. The problem is particularly prominent when the secondary circuit cables in the terminal box of the current transformer are messy. The redundant, cumbersome and error-prone work of checking the secondary circuit of the current transformer has always plagued grassroots power workers.

[0003] Although the correctness of the circuit is ensured, the workload faced by the staff is very large when there are dozens of current transformers for the whole station acceptance or renovation. At the same time, incorrect wiring may occur during the restoration process after calibration, which may lead to secondary open circuits or protection tripping or even more serious consequences. There is an urgent need for a new calibration method and equipment to solve this frequent and troublesome problem in the field. Summary of the Invention

[0004] In view of the aforementioned existing problems, the present invention is proposed.

[0005] Therefore, the present invention provides a method and system for calibrating the secondary circuit of a current transformer, which solves the problems of traditional secondary circuit calibration methods being time-consuming, labor-intensive, complex, and slow, and having messy secondary circuit cable distribution.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0007] In a first aspect, the present invention provides a method for calibrating the secondary circuit of a current transformer, comprising:

[0008] Obtain the secondary circuit wiring information of the current transformer, and configure the secondary circuit calibration module of the current transformer according to the secondary circuit wiring information of the current transformer;

[0009] The wiring condition of the secondary circuit calibration module is checked.

[0010] In the case of wiring errors, the type of wiring error is identified by the response of the secondary circuit correction module, and the wiring error type is corrected accordingly.

[0011] As a preferred embodiment of the current transformer secondary circuit calibration method of the present invention, the current transformer secondary circuit calibration module includes: AC power supply, DC power supply, detection lamp, photoresistor, indicator light and alarm electronic components.

[0012] The detection lamp and photoresistor are reliably packaged to form an electro-optic coupling module, and the detection lamp is the only internal power source.

[0013] The AC power supply and the detection lamp form the detection circuit;

[0014] The alarm circuit consists of a photoresistor, an indicator light, and alarm electronic components.

[0015] As a preferred embodiment of the current transformer secondary circuit alignment method of the present invention, it further includes:

[0016] When the circuit is not calibrated, the test lamp is not connected to the AC power supply circuit, the resistance of the test circuit is infinite, and the test lamp does not light up.

[0017] When no calibration is performed, the light intensity inside the electro-optic coupling module is zero, the resistance of the photoresistor is greater than the first threshold, the current in the detection circuit is less than the second threshold, the indicator light does not light up, and the alarm electronic components do not sound.

[0018] In a preferred embodiment of the current transformer secondary circuit calibration method of the present invention, the calibration detection of the wiring condition of the secondary circuit calibration module includes:

[0019] The first operator grounds the tap to be tested at the current transformer terminal box using a grounding wire. The second operator connects one end of the current transformer secondary circuit calibration module to the terminal to be tested at the terminal box and grounds the other end of the current transformer secondary circuit calibration module nearby.

[0020] As a preferred embodiment of the current transformer secondary circuit alignment method of the present invention, it further includes:

[0021] When the secondary circuits of the current transformer are all correctly wired, the circuit connected to the current transformer secondary circuit calibration module does not include the winding. The external circuit to be connected is equivalent to a short circuit, the indicator light is on and the alarm electronic components are conducting.

[0022] In a preferred embodiment of the current transformer secondary circuit calibration method described in this invention, the wiring errors include:

[0023] When the wiring is incorrect, the external circuit to be connected is connected to a winding with a resistance value greater than the third threshold. If the current in the response circuit does not reach the response value of the indicator light and alarm electronic components, the indicator light will not light up and the alarm electronic components will not sound.

[0024] As a preferred embodiment of the current transformer secondary circuit calibration method described in this invention, the wiring error types include:

[0025] Open circuit in the cable, reversed cable connection, and incorrect connection of cables with different windings;

[0026] When an open circuit or reversed cable occurs during calibration, the external circuit to be connected to the current transformer secondary circuit calibration module is equivalent to an open circuit. The AC current and the detection lamp form a non-conductive circuit, the detection lamp does not light up, the resistance of the photoresistor in the electro-optic coupling module is greater than the first threshold, the alarm circuit does not conduct, the indicator light does not light up and the alarm electronic components do not sound.

[0027] When cables with different windings are connected incorrectly during calibration, the external circuit to be connected to the current transformer secondary circuit calibration module is equivalent to connecting one winding. The impedance of the winding inside the current transformer is greater than the third threshold. The circuit formed by the AC power supply and the detection lamp is not conductive, the detection lamp does not light up, the resistance of the photoresistor in the electro-optic coupling module is greater than the first threshold, the alarm circuit is not conductive, the indicator light does not light up, and the alarm electronic components do not sound.

[0028] Secondly, the present invention provides a current transformer secondary circuit calibration system, comprising:

[0029] The configuration module is used to obtain the wiring information of the secondary circuit of the current transformer and configure the secondary circuit calibration module of the current transformer according to the wiring information of the secondary circuit of the current transformer.

[0030] The wiring calibration module is used to perform wiring calibration detection on the secondary circuit wiring calibration module;

[0031] The correction module is used to identify the type of wiring error by responding to the secondary circuit correction module, and to correct the wiring error accordingly.

[0032] Thirdly, the present invention provides a computing device, comprising:

[0033] Memory and processor;

[0034] The memory is used to store computer-executable instructions, and the processor is used to execute the computer-executable instructions, which, when executed by the processor, implement the steps of the current transformer secondary circuit alignment method.

[0035] Fourthly, the present invention provides a computer-readable storage medium storing computer-executable instructions that, when executed by a processor, implement the steps of the current transformer secondary circuit alignment method.

[0036] Compared with existing technologies, the advantages of this invention are: This invention can verify the secondary circuit of a current transformer without disconnecting the wiring, and the verification process is quick and accurate. The method and device are simple to operate, requiring no specialized technical skills from the verification personnel. Verification only requires using the device to perform individual grounding measurements, and the verification work can be completed by observing the device's buzzer and indicator lights. Attached Figure Description

[0037] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0038] Figure 1 This is a schematic diagram of the overall flow logic of the current transformer secondary circuit alignment method according to an embodiment of the present invention;

[0039] Figure 2 This is a schematic diagram of the current transformer secondary circuit calibration method according to an embodiment of the present invention during normal calibration.

[0040] Figure 3 This is a schematic diagram of the current transformer secondary circuit calibration method according to an embodiment of the present invention when there is a wiring error.

[0041] Figure 4 This is a schematic diagram of the current transformer secondary circuit calibration method according to an embodiment of the present invention during normal calibration.

[0042] Figure 5 This is a schematic diagram of the current transformer secondary circuit calibration method according to an embodiment of the present invention. Detailed Implementation

[0043] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.

[0044] Example 1

[0045] Reference Figures 1-5 As an embodiment of the present invention, a method for calibrating the secondary circuit of a current transformer is provided, comprising:

[0046] S100: Obtain the secondary circuit wiring information of the current transformer and configure the secondary circuit calibration module of the current transformer according to the secondary circuit wiring information of the current transformer.

[0047] S200: Perform wiring verification tests on the secondary circuit wiring module;

[0048] S300: In the event of a wiring error, the type of wiring error is identified through the response of the secondary circuit correction module, and the wiring error type is corrected accordingly;

[0049] It should be noted that the electro-optic coupling module can quickly detect the wiring condition, greatly shortening the calibration time. Compared with traditional methods, the calibration efficiency is significantly improved. Only two people are needed to complete the calibration work, reducing the required human resources and labor costs. The intuitive response of the electro-optic coupling module can accurately determine whether the wiring is correct, reducing human error.

[0050] In this embodiment of the application, step S100 includes the following sub-steps A1-A4;

[0051] In A1: The secondary circuit calibration module for the current transformer includes: AC power supply, DC power supply, detection lamp, photoresistor, indicator light and alarm electronic components;

[0052] In A2: the detection lamp and the photoresistor are reliably packaged to form an electro-optic coupling module, and the detection lamp is the only internal power source;

[0053] In A3: the AC power supply and the detection lamp form the detection circuit;

[0054] In A4: the photoresistor, indicator light and alarm electronic components form the alarm circuit.

[0055] Specifically, the detection lamp types include, but are not limited to, conventional small light bulbs and various light-emitting diodes. Alarm electronic components include, but are not limited to, buzzers, vibrators, and speakers. The detection lamp and photoresistor are reliably packaged to form an electro-optic coupling module. The detection lamp has a unique internal power supply, preventing external light from entering. The AC power supply and the detection lamp form the detection circuit; the external circuit to be connected is the circuit connected to the device's lead-out terminals. The photoresistor, indicator light, and buzzer form the alarm circuit. When the external wiring is correct, the circuit is conductive, releasing various prompt signals; when the external wiring is incorrect, the device will not release any signal.

[0056] It should be noted that the electro-optic coupling module utilizes the high sensitivity of the photoresistor to changes in light intensity to accurately detect the light signal of the detection lamp, thereby determining the correctness of the wiring. The reliable encapsulation of the detection lamp and photoresistor ensures the stability and durability of the module, preventing interference from the external environment on the detection results. The detection lamp, as the only internal light source, ensures the accuracy of the detection, and external light cannot enter, avoiding interference from external light on the detection results. Intuitive feedback is provided through indicator lights and alarm electronic components (such as buzzers, vibrators, and horns), allowing operators to quickly determine whether the wiring is correct.

[0057] In this embodiment of the application, after completing steps A1-A4, step S200 also includes the following steps A5-A6;

[0058] In A5: When no calibration is performed, the test lamp is not connected to the AC power circuit, the resistance of the test circuit is infinite, and the test lamp does not light up.

[0059] In A6: When no calibration is performed, the light intensity inside the electro-optic coupling module is zero, the resistance of the photoresistor is greater than the first threshold, the current in the detection circuit is less than the second threshold, the indicator light does not light up, and the alarm electronic components do not sound.

[0060] Specifically, before calibration, the test lamp is not connected to the AC power supply circuit, and the resistance of the test circuit is infinite. Therefore, the test lamp does not light up. This can be explained by the formula for a photoresistor:

[0061]

[0062] Where I is the light intensity, R is the resistance of the photoresistor, and k is a constant that depends on the characteristics of the photoresistor and the unit of light intensity.

[0063] The resistance of a photoresistor is inversely proportional to the light intensity; that is, the greater the light intensity, the smaller the resistance of the photoresistor; the greater the light intensity, the greater the resistance of the photoresistor.

[0064] When the circuit is not calibrated, the light intensity inside the electro-optic coupling module is zero. Therefore, the resistance of the photoresistor is greater than the first threshold of 100MΩ. At this time, the current in the detection circuit is less than the second threshold of 1mA. Therefore, the indicator light does not light up and the buzzer does not sound.

[0065] It should be noted that by defining the initial state before calibration, operators can clearly know the system's state before calibration begins, which helps reduce misoperation and misunderstanding. It also clarifies that the detection lamp and AC power circuit are not conducting, and that the photoresistor has a high resistance value, ensuring that the system will not falsely trigger the alarm circuit when there is no external interference, thus improving the accuracy of detection. By setting thresholds, the system can work stably under different environmental conditions and will not make misjudgments due to slight changes in ambient light.

[0066] In this embodiment of the application, step S200 above includes the following sub-steps B1-B2;

[0067] In B1: The first operator grounds the tap to be tested at the current transformer terminal box using a grounding wire. The second operator connects one end of the current transformer secondary circuit calibration module to the terminal to be tested at the terminal box and grounds the other end of the current transformer secondary circuit calibration module nearby.

[0068] In B2: When the secondary circuits of the current transformer are all correctly wired, the circuit connected to the current transformer secondary circuit calibration module does not include the winding. The external circuit to be connected is equivalent to a short circuit, the indicator light is on and the alarm electronic components are conducting.

[0069] Specifically, such as Figure 2 As shown, two operators are required to complete this task. When the wiring is correct, the external circuit to be connected is equivalent to a short circuit. At this time, the internal AC power supply and lamp circuit are connected and the lamp is lit. Therefore, the light intensity inside the electro-optic coupling module increases significantly. Since the resistance of the photoresistor is inversely proportional to the light intensity and changes very sensitively, the resistance of the photoresistor drops rapidly to zero. At this time, the current inside the response circuit increases significantly and reaches the response current of 1mA of the indicator light and buzzer. The indicator light of the corresponding circuit lights up and the buzzer is turned on.

[0070] It should be noted that the collaborative work of two operators can significantly improve the efficiency of the calibration work and reduce the workload that a single operator needs to complete. Through the cooperation of two operators, the safety of the operators can be guaranteed during the calibration operation. Especially in high-voltage environments, when the wiring is correct, the instrument transformer secondary circuit calibration module can respond quickly and give an indication, so that the operator can know the calibration result immediately.

[0071] In this embodiment of the application, step S300 above includes the following sub-step C1;

[0072] In C1: When the wiring is incorrect, the external circuit to be connected is connected to a winding with a resistance value greater than the third threshold. If the current of the response circuit does not reach the response value of the indicator light and alarm electronic components, the indicator light will not light up and the alarm electronic components will not sound.

[0073] Specifically, when a wiring error occurs, the external circuit to be connected will be open-circuited or connected to a winding with an impedance greater than the third threshold of 60Ω. In the schematic diagram, the current in the left-hand detection circuit is very small, and the intensity of the detection light significantly decreases to near extinguish. At this time, the light intensity inside the electro-optic coupling module is very small, and the resistance of the photoresistor rapidly increases to near infinity. This results in a very small current in the right-hand response circuit that does not reach the response values ​​of the indicator light and buzzer; therefore, the indicator light does not illuminate and the buzzer does not sound. This allows for accurate judgment of the wiring in the secondary circuit of the current transformer.

[0074] It should be noted that by setting a third threshold, wiring errors can be accurately identified. This is because only when the external circuit is connected to a winding with a resistance greater than this threshold will the current in the response circuit fail to reach the response value of the indicator light and alarm electronic components. When the wiring is incorrect, the indicator light will not illuminate and the alarm electronic components will not sound. This instant feedback mechanism allows operators to quickly identify problems and take corresponding corrective measures. By observing the changes in light intensity inside the electro-optic coupling module and the rapid changes in the resistance of the photoresistor, it is possible to accurately determine whether the external wiring is correct, thus improving the accuracy of wiring calibration.

[0075] In this embodiment of the application, after completing step C1, step S300 above also includes the following sub-steps C2-C4;

[0076] In C2: open circuit in cable, reversed cable connection, and incorrect connection of cables with different windings;

[0077] In C3: When an open circuit or reversed cable occurs during calibration, the external circuit to be connected in the calibration module of the transformer secondary circuit is equivalent to an open circuit. The AC current and the detection lamp form a non-conductive circuit, the detection lamp does not light up, the resistance of the photoresistor in the electro-optic coupling module is greater than the first threshold, the alarm circuit does not conduct, the indicator light does not light up and the alarm electronic components do not sound.

[0078] In C4: When cables with different windings are connected incorrectly during calibration, the external circuit to be connected in the calibration module of the current transformer secondary circuit is equivalent to connecting one winding. The impedance of the winding inside the current transformer is greater than the third threshold. The circuit formed by the AC power supply and the detection lamp is not conductive, the detection lamp does not light up, the resistance of the photoresistor in the electro-optic coupling module is greater than the first threshold, the alarm circuit is not conductive, the indicator light does not light up and the alarm electronic components do not sound.

[0079] Specifically, such as Figure 3 As shown, there are three scenarios when a wiring error occurs in the secondary circuit:

[0080] Due to cable damage and crimping of the insulation lamp, the cable is open-circuited. In this case, the external circuit to be connected to the device can be directly equivalent to an open circuit.

[0081] Due to negligence, the two cables in the same winding were connected in reverse, as shown in the attached diagram. Figure 3 The upper middle part, 3S1 and 3S3, at this time the external circuit to be connected to the device can be directly equivalent to an open circuit;

[0082] Cables with different windings are connected incorrectly, such as... Figure 3 The upper middle part 1S1, 1S2, 2S1 and 2S2, at this time the external circuit to be connected to the device can be directly equivalent to the inductance connected to the winding.

[0083] For example, in a substation site, there is a current transformer terminal box on the ground near the current transformer, and the current transformer to be calibrated is located nearby at a higher elevation. When using this device for calibration, one person holds the calibration device at the ground terminal box to direct the operation. Another person carries a grounding wire, climbs up to the current transformer tap box, opens the box cover, and waits for instructions.

[0084] Assume the correct wiring in the attached diagram should be TA1-1S1, TA2-1S2, TA3-2S1, TA4-2S2, TA5-3S1, TA6-3S2, TA7-3S3. Due to human error, some windings are incorrectly connected, but this is not immediately apparent. It is now necessary to verify the correctness of each cable. The wiring calibration steps using this method and device are as follows:

[0085] The person directing the operation at the terminal box ensures the device's grounding terminal is reliably grounded, and then reliably contacts the TA1 terminal with the other terminal wire of the device. Simultaneously, they instruct the personnel assisting at the current transformer via shouting or telephone to reliably ground the 1S1 terminal. If the device's indicator light illuminates and the buzzer sounds, it indicates that the cable is correctly wired according to the expected requirements. Here, due to the incorrect wiring, the device is clearly unresponsive; therefore, the wiring is determined to be incorrect.

[0086] After detecting a wiring error in TA1 and 1S1, the operator at the terminal box keeps the device's grounding wire stationary and sequentially connects the other lead terminal of the device to the terminals excluding TA1 (TA2-TA7). If the device's alarm light illuminates and the buzzer sounds when a terminal is touched, it indicates that the 1S1 tap is connected to that position. In this case, since 1S1 is actually incorrectly connected to TA3, the device will respond when TA3 is touched.

[0087] After the error was discovered, the personnel at the terminal box swapped the cables of terminals TA1 and TA3. At this point, the 1S1-TA1 cable verification and error correction were completed.

[0088] Similarly, at the current transformer, the coordinating personnel ground the 1S2 tap, and at the terminal box, the directing personnel contact TA1-TA7 in sequence. The indicator light illuminates and the buzzer sounds only at TA2, indicating that 1S2 and TA2 are correctly connected. If an error occurs, correct the cable according to the above steps.

[0089] After completing the calibration of terminals TA1-TA7 and each tap and restoring the cables, check each terminal again to ensure that the device only responds at the expected wiring terminals.

[0090] Specifically, such as Figure 4 and Figure 5 As shown, if an open circuit or reversed cable connection occurs during cable calibration, the external circuit to be connected to the device is equivalent to an open circuit. The working principle of the device in this case is as follows: Figure 4 As shown, the circuit formed by the AC power supply and the lamp on the left is not conductive, so the detection lamp does not light up. The light intensity inside the electro-optic coupling module is insufficient, and the resistance of the photoresistor is greater than the first threshold of 100MΩ. At this time, the alarm circuit on the right is not conductive, so the indicator light does not light up and the buzzer does not sound.

[0091] When cables with different windings are connected incorrectly during calibration, the external circuit to be connected to the device is equivalent to connecting one winding. In this case, the device's operating principle is as follows: Figure 5 As shown. Because the impedance of the winding inside the current transformer is greater than the third threshold of 60Ω, the circuit formed by the AC power supply and the lamp on the left is not conductive, the detection lamp does not light up, and the light intensity in the electro-optic coupling module is insufficient, causing the photoresistor resistance to exceed the first threshold of 100MΩ. At this time, the alarm circuit on the right is not conductive, so the indicator light does not light up and the buzzer does not sound.

[0092] It should be noted that by specifically defining situations such as open circuits, reversed connections, and incorrect connections of different windings, the type of wiring error can be accurately diagnosed, improving the accuracy of fault diagnosis. When a wiring error occurs, the indicator light does not illuminate and the alarm electronic components do not sound, providing immediate fault feedback. This allows operators to quickly identify and respond to the fault. Through accurate error identification and feedback, operators can troubleshoot the fault safely, avoiding potential safety accidents caused by incorrect wiring.

[0093] The above is a schematic scheme of a current transformer secondary circuit calibration method according to this embodiment. It should be noted that the technical solution of this current transformer secondary circuit calibration system and the technical solution of the current transformer secondary circuit calibration method described above belong to the same concept. For details not described in detail in the technical solution of the current transformer secondary circuit calibration system in this embodiment, please refer to the description of the technical solution of the current transformer secondary circuit calibration method described above.

[0094] In this embodiment, the current transformer secondary circuit calibration system includes:

[0095] The configuration module is used to obtain the wiring information of the secondary circuit of the current transformer and configure the secondary circuit calibration module of the current transformer according to the wiring information of the secondary circuit of the current transformer.

[0096] The wiring calibration module is used to perform wiring calibration detection on the secondary circuit wiring calibration module;

[0097] The correction module is used to identify the type of wiring error by responding to the secondary circuit correction module, and to correct the wiring error accordingly.

[0098] This embodiment also provides a computing device applicable to the calibration of the secondary circuit of a current transformer, including:

[0099] The system includes a memory and a processor. The memory stores computer-executable instructions, and the processor executes these instructions to implement the current transformer secondary circuit alignment method proposed in the above embodiments.

[0100] This embodiment also provides a storage medium storing a computer program that, when executed by a processor, implements the current transformer secondary circuit alignment method proposed in the above embodiments.

[0101] The storage medium proposed in this embodiment and the method for calibrating the secondary circuit of a current transformer proposed in the above embodiments belong to the same inventive concept. Technical details not described in detail in this embodiment can be found in the above embodiments, and this embodiment has the same beneficial effects as the above embodiments.

[0102] Based on the above description of the implementation methods, those skilled in the art will clearly understand that the present invention can be implemented using software and necessary general-purpose hardware, and of course, it can also be implemented using hardware. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as a computer floppy disk, read-only memory (ROM), random access memory (RAM), flash memory, hard disk, or optical disk, etc., including several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods of the various embodiments of the present invention.

[0103] Example 2

[0104] Referring to Tables 1-2, this embodiment differs from the first embodiment and provides a verification test for a current transformer secondary circuit calibration method, to verify and explain the technical effects used in this method.

[0105] On-site testing was conducted on the secondary circuit acceptance phase of the main transformer expansion project of a 220kV substation.

[0106] During the test, one person climbed onto the main transformer to perform grounding operations on the terminal boxes of the medium, high, and low current transformers. Another person used a line-checking device to check the wiring at the main transformer's terminal box. The line-checking device was used to test the secondary circuit of the transformer's current transformer (CT). The test results are shown in Table 1 below. The results show that the device successfully detected two secondary wiring errors in the main transformer.

[0107] Table 1. Field Test Results of Instrument Transformer Secondary Circuit Calibration Method

[0108]

[0109]

[0110] As shown in Table 1, the calibration process only requires two groups of people to cooperate. The calibration process does not require disconnection at both ends of the wiring to be tested. It can be done by telephone. The entire calibration process takes only about 10 minutes. The calibration device is convenient and simple to use. The traditional method of calibrating the secondary circuit of the current transformer based on a multimeter takes a total of 1 hour. This greatly reduces the calibration time and cost and effectively improves the accuracy of the wiring work of the secondary circuit of the current transformer.

[0111] Table 2 Comparison of the method in this application with existing methods

[0112]

[0113]

[0114] Compared with the two traditional calibration methods, the calibration results of this application require less time, greatly improve calibration efficiency, require less manpower, and do not have the problem of calibration failure in special circumstances. Furthermore, it is low-cost and portable.

[0115] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for calibrating the secondary circuit of a current transformer, characterized in that, include: Obtain the secondary circuit wiring information of the current transformer, and configure the secondary circuit calibration module of the current transformer according to the secondary circuit wiring information of the current transformer; The wiring condition of the secondary circuit calibration module is checked. In the case of wiring errors, the type of wiring error is identified by the response of the secondary circuit correction module, and the wiring error type is corrected accordingly. The current transformer secondary circuit calibration module includes: AC power supply, DC power supply, detection lamp, photoresistor, indicator light and alarm electronic components; The detection lamp and photoresistor are reliably packaged to form an electro-optic coupling module, and the detection lamp is the only internal power source. The AC power supply and the detection lamp form the detection circuit; The alarm circuit consists of a photoresistor, an indicator light, and alarm electronic components. Also includes: When the circuit is not calibrated, the test lamp is not connected to the AC power supply circuit, the resistance of the test circuit is infinite, and the test lamp does not light up. When no calibration is performed, the light intensity inside the electro-optic coupling module is zero, the resistance of the photoresistor is greater than the first threshold, the current in the detection circuit is less than the second threshold, the indicator light does not light up, and the alarm electronic components do not sound. The wiring check of the secondary circuit calibration module includes: The first operator grounds the tap to be tested at the current transformer terminal box using a grounding wire. The second operator connects one end of the current transformer secondary circuit calibration module to the terminal to be tested at the terminal box and grounds the other end of the current transformer secondary circuit calibration module nearby. Also includes: When the secondary circuit of the current transformer is correctly wired, the circuit connected to the secondary circuit calibration module of the current transformer does not include the winding. The external circuit to be connected is equivalent to a short circuit, the indicator light is on and the alarm electronic components are conducting. Wiring errors include: When the wiring is incorrect, the external circuit to be connected is connected to a winding with a resistance value greater than the third threshold. If the current in the response circuit does not reach the response value of the indicator light and alarm electronic components, the indicator light will not light up and the alarm electronic components will not sound.

2. The current transformer secondary circuit alignment method as described in claim 1, characterized in that, Wiring error types include: Open circuit in the cable, reversed cable connection, and incorrect connection of cables with different windings; When an open circuit or reversed cable occurs during calibration, the external circuit to be connected to the current transformer secondary circuit calibration module is equivalent to an open circuit. The AC current and the detection lamp form a non-conductive circuit, the detection lamp does not light up, the resistance of the photoresistor in the electro-optic coupling module is greater than the first threshold, the alarm circuit does not conduct, the indicator light does not light up and the alarm electronic components do not sound. When cables with different windings are connected incorrectly during calibration, the external circuit to be connected to the current transformer secondary circuit calibration module is equivalent to connecting one winding. The impedance of the winding inside the current transformer is greater than the third threshold. The circuit formed by the AC power supply and the detection lamp is not conductive, the detection lamp does not light up, the resistance of the photoresistor in the electro-optic coupling module is greater than the first threshold, the alarm circuit is not conductive, the indicator light does not light up, and the alarm electronic components do not sound.

3. A system applying the current transformer secondary circuit alignment method as described in any one of claims 1-2, characterized in that, include: The configuration module is used to obtain the wiring information of the secondary circuit of the current transformer and configure the secondary circuit calibration module of the current transformer according to the wiring information of the secondary circuit of the current transformer. The wiring calibration module is used to perform wiring calibration detection on the secondary circuit wiring calibration module; The correction module is used to identify the type of wiring error by responding to the secondary circuit correction module, and to correct the wiring error accordingly.

4. An electronic device, comprising: Memory and processor; The memory is used to store computer-executable instructions, and the processor is used to execute the computer-executable instructions. When the computer-executable instructions are executed by the processor, they implement the steps of the current transformer secondary circuit alignment method according to any one of claims 1 to 2.

5. A computer-readable storage medium storing computer-executable instructions that, when executed by a processor, implement the steps of the current transformer secondary circuit alignment method according to any one of claims 1 to 2.

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