A detection device and method for a secondary load of a current transformer

Abstract

The application relates to a detection device and method for a secondary load of a current transformer, wherein the detection device for the secondary load of the current transformer comprises a main control module and a detection module, a loop switching module, which are electrically connected, and are used for sending control instructions and obtaining detection results; a connection module, which is electrically connected with a secondary wiring box and a switch terminal box of the current transformer, and is also electrically connected with the detection module and the loop switching module; the detection module is used for applying rated current to the connection module and collecting the voltage of the connection module; the loop switching module comprises at least two relay modules, each relay module is electrically connected with a winding of the current transformer, the relay module comprises a relay, a driving circuit and a control unit, the relay is electrically connected with the driving circuit and the connection module, and the control unit is electrically connected with the driving circuit and the main control module. Through the application, the detection efficiency of the current transformer is improved.

Description

Technical Field

[0001] This application relates to the field of power detection, and in particular to a detection device and method for the secondary load of a current transformer. Background Technology

[0002] The secondary load of a current transformer is the sum of the impedances of all components in the secondary circuit of the current transformer. The secondary load test requires wiring the secondary circuit of each winding in the current transformer and calculating the impedance of the secondary circuit. During the secondary load test, connections need to be made at three locations: the relay protection device, the secondary junction box of the current transformer, and the switch terminal box. Specifically, a closed loop is formed by short-circuiting the secondary winding terminals at the secondary junction box, and a current test lead is connected at the switch terminal box to inject current into the closed loop. The loop voltage is then measured using a multimeter to obtain the load and impedance of the secondary circuit.

[0003] Current transformers are typically equipped with multiple secondary windings. During each secondary load test, three positions need to be operated on each winding. This requires maintenance personnel to repeatedly climb ladders and change wiring during the secondary load test. For maintenance personnel, this is not only extremely labor-intensive but also time-consuming, thus resulting in low testing efficiency for secondary load tests. Summary of the Invention

[0004] This application provides a detection device and method for the secondary load of a current transformer, which at least solves the problem of low detection efficiency in the detection of the secondary load of a current transformer in related technologies.

[0005] In a first aspect, embodiments of this application provide a detection device for the secondary load of a current transformer, comprising: a main control module, a detection module, a circuit switching module, and a connection module; The main control module is electrically connected to the detection module and the loop switching module, and is used to send control commands and obtain detection results; The connection module is electrically connected to the secondary junction box and switch terminal box of the current transformer, and is also electrically connected to the detection module and the circuit switching module; The detection module is used to apply a rated current to the connection module and to acquire the voltage of the connection module; The circuit switching module includes at least two relay modules. Each relay module includes a relay, a drive circuit, and a control unit. The relay is electrically connected to the drive circuit and the connection module. The control unit is electrically connected to the drive circuit and the main control module and is used to receive switching commands from the main control module and control the on / off state of the relay.

[0006] In one embodiment, the detection module includes: a current output module, a voltage acquisition module, and an automatic verification module; The current output module is electrically connected to the connection module and the automatic verification module, and is used to output the rated current to the connection module; A voltage acquisition module is electrically connected to the connection module and the automatic verification module, and is used to acquire the voltage of the connection module; An automatic verification module, electrically connected to the main control module, is used to sequentially control the rated current output module to output current, and the voltage acquisition module to acquire the voltage.

[0007] In one embodiment, the main control module includes: The instruction module is used to transmit control instructions. The instruction module includes a button unit and a storage unit. The button unit is electrically connected to the main control module and is used to input the control instructions and determine the rated current. The storage unit is electrically connected to the main control module and is used to store the verification scheme and the detection results. The main control module is electrically connected to the automatic verification module for acquiring the detection results, electrically connected to the loop switching module for transmitting switching commands to the control module, and electrically connected to the display module and the generation module. The display module is used to display the detection results; The generation module is used to generate inspection reports.

[0008] In one embodiment, the main control module further includes: The USB interface is electrically connected to the main control module and is used to export the inspection report.

[0009] In one embodiment, the device further includes: A battery module is electrically connected to the main control module. The battery module includes a charging / discharging module, a lithium battery, and a converter. The charging / discharging module is electrically connected to the battery and the converter, and the converter is electrically connected to the main control module.

[0010] Secondly, embodiments of this application provide a method for detecting the secondary load of a current transformer, comprising: Upon acquiring control commands and rated current, and in response to the control commands for the current transformer winding, the main control module activates the relays in the control loop switching module. Detection steps: When the relay is energized, the main control module controls the detection module to output the rated current to the connected module and obtains the voltage of the connected module. Based on the voltage and the rated current, the load power is obtained. The load power is compared with the preset load power to obtain the detection result. Based on the detection results, the main control module sends a switching command to the circuit switching module. In response to the switching command, the circuit switching module disconnects the relay of the current winding, engages the relay of the next winding, and executes the detection steps again to obtain the detection results of the next winding, until all windings have been detected.

[0011] In one embodiment, comparing the load power with a preset load power to obtain a detection result includes: Compare the load power with the preset load power. If the load power is less than the preset load power, then the current winding load is qualified. If the load power is greater than or equal to the preset load power, then the current winding load is unqualified.

[0012] In one embodiment, regarding the winding of the current transformer, the main control module responds to a control command by engaging a relay in the control loop switching module, including: For the winding of the current transformer, the main control module responds to the control command and controls the control unit in the circuit switching module to transmit a start signal to the relay; The relay responds to the start signal by engaging its contacts.

[0013] In one embodiment, when the relay is energized, the main control module controls the detection module to output the rated current to the connection module and obtains the voltage of the connection module, including: The main control module sends the control command to the automatic verification module. In response to the control command, the automatic verification module controls the current output module to output the rated current to the connection module, and collects the voltage of the connection module through the voltage acquisition module, and obtains the voltage in the automatic verification module.

[0014] The detection device and method for the secondary load of a current transformer provided in this application have at least the following technical effects: The testing device is connected to the secondary circuit of the current transformer via a connection module. Control commands are sent from the main control module, which switches different windings using relay modules in the control circuit switching module. The testing module applies rated current to the connection module and collects voltage data from the connection module. The main control module then obtains the test results for each winding. The testing device connects before testing and, during testing, controls different relay modules via the main control module to apply rated current and collect voltage data from different windings, enabling rapid testing of each winding. The testing device connects to the current transformer before testing and disconnects after testing. It automatically switches windings and performs automatic testing during the testing process, allowing for testing of each winding. This reduces the number of times testing personnel need to climb and the workload of rewiring when switching different windings, thereby improving the efficiency of testing the secondary load of the current transformer.

[0015] Details of one or more embodiments of this application are set forth in the following drawings and description to make other features, objects and advantages of this application more readily apparent. Attached Figure Description

[0016] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings: Figure 1 This is a schematic diagram of a detection device for the secondary load of a current transformer, according to an exemplary embodiment. Figure 2 This is a schematic diagram illustrating a relay module according to an exemplary embodiment; Figure 3 This is a schematic diagram illustrating the connection between a detection device and a current transformer according to an exemplary embodiment; Figure 4 This is a schematic diagram of a detection device for the secondary load of a current transformer, according to another exemplary embodiment. Figure 5 This is a schematic diagram of a main control module according to an exemplary embodiment; Figure 6 This is a schematic diagram of the main control module according to another exemplary embodiment; Figure 7 This is a schematic diagram of a detection device for the secondary load of a current transformer, according to another exemplary embodiment. Figure 8 This is a schematic diagram illustrating the control panel of the detection device according to an exemplary embodiment; Figure 9 This is a schematic diagram illustrating the terminals according to an exemplary embodiment; Figure 10This is a flowchart illustrating a method for detecting the secondary load of a current transformer according to an exemplary embodiment; Figure 11 This is a schematic diagram of a loop connection according to an exemplary embodiment; Figure 12 This is a schematic diagram illustrating loop switching according to an exemplary embodiment.

[0017] In the above figures, the meanings of the reference numerals are as follows: 100. Main control module; 101. Main control module; 102. Command module; 103. Display module; 104. Generation module; 105. USB interface; 200. Connection module; 300. Detection module; 301. Automatic verification module; 302. Current output module; 303. Voltage acquisition module; 400. Loop switching module; 401. Relay module; 1. First connection module; 2. Second connection module; 3. Three-hole socket; 4. Rocker switch; 5. Grounding contact; 11. Button unit; 12. Storage unit; 41. Relay; 42. Control unit; 43. Drive circuit; 51. Charging and discharging module; 52. Converter; 53. Lithium battery. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this application clearer, the application is described and illustrated below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application. All other embodiments obtained by those skilled in the art based on the embodiments provided in this application without inventive effort are within the scope of protection of this application.

[0019] Obviously, the accompanying drawings described below are merely some examples or embodiments of this application. Those skilled in the art can apply this application to other similar scenarios based on these drawings without any inventive effort. Furthermore, it is understood that although the efforts made in this development process may be complex and lengthy, for those skilled in the art related to the content disclosed in this application, any changes to design, manufacturing, or production based on the technical content disclosed in this application are merely conventional technical means and should not be construed as insufficient disclosure of the content of this application.

[0020] In this application, the reference to "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this application may be combined with other embodiments without conflict.

[0021] Unless otherwise defined, the technical or scientific terms used in this application shall have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms “a,” “an,” “an,” “the,” and similar words used in this application do not indicate quantity limitation and may indicate singular or plural. The terms “comprising,” “including,” “having,” and any variations thereof used in this application are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or device that includes a series of steps or modules (units) is not limited to the listed steps or units, but may also include steps or units not listed, or may include other steps or units inherent to these processes, methods, products, or devices. The terms “connected,” “linked,” “coupled,” and similar words used in this application are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. “Multiple” used in this application refers to two or more. “And / or” describes the relationship between related objects, indicating that three relationships may exist; for example, “A and / or B” can represent: A alone, A and B simultaneously, and B alone. The character " / " generally indicates that the preceding and following objects are in an "or" relationship. The terms "first," "second," and "third" used in this application are merely to distinguish similar objects and do not represent a specific ordering of the objects.

[0022] In a first aspect, embodiments of this application provide a detection device for the secondary load of a current transformer. Figure 1 This is a schematic diagram of a detection device for the secondary load of a current transformer, according to an exemplary embodiment. Figure 2 This is a schematic diagram illustrating a relay module according to an exemplary embodiment, such as... Figure 1 and Figure 2 As shown, a detection device for the secondary load of a current transformer includes: a main control module 100, a connection module 200, a detection module 300, and a circuit switching module 400.

[0023] The main control module 100 is electrically connected to the detection module 300 and the loop switching module 400, and is used to send control commands and acquire detection results. The connection module 200 is electrically connected to the secondary junction box and switch terminal box of the current transformer, and is also electrically connected to the detection module 300 and the loop switching module 400. The detection module 300 is used to apply rated current to the connection module 200 and to acquire the voltage of the connection module 200. The loop switching module 400 includes at least two relay modules 401. Each relay module 401 is electrically connected to a winding of the current transformer. The relay module 401 includes a relay 41, a control unit 42, and a drive circuit 43. The relay 41 is electrically connected to the drive circuit 43 and the connection module 200. The control unit 42 is electrically connected to the drive circuit 43 and the main control module 100, and is used to receive switching commands from the main control module 100 and control the on / off state of the relay 41.

[0024] The circuit switching module 400 automatically switches between different current transformer windings through the relay module 401, eliminating the need for multiple line disassemblies and reconnections, reducing the workload of testing personnel and improving the efficiency of line replacement work.

[0025] The main control module 100 sends control commands to the detection module 300 and the loop switching module 400. The loop switching module 400, based on the control commands, controls a relay module 401 to engage, ensuring that the detection device only detects the secondary circuit of one winding in the current transformer. Upon receiving the control commands, the detection module 300 outputs rated current to the connection module 200 to transmit the current to the current transformer. After outputting the rated current, the secondary circuit of the current transformer receives the current and transmits the resulting voltage to the detection module 300 through the connection module 200. The detection module 300 transmits the output current and the received voltage to the main control module 100. The main control module 100 determines the load power in the secondary circuit of the current transformer based on the current and voltage, determines whether the currently detected secondary load is qualified, and obtains the detection result. After obtaining the detection results, the main control module 100 sends a switching command to the loop switching module 400 to disconnect the current relay module 401 and engage the next adjacent relay module 401, thereby realizing automatic switching between different windings of the current transformer and completing the detection of the secondary load of different windings of the current transformer.

[0026] It should be noted that the connection module 200 includes several connection posts, which are used for the secondary junction box and switch terminal box of the current transformer outside the electrical connection detection device, as well as the detection module 300 and circuit switching module 400 inside the electrical connection device. The connection module 200 centralizes the connections that the testing personnel need to make at three working positions, effectively reducing connection time and improving testing efficiency.

[0027] Figure 3 This is a schematic diagram illustrating the connection between a detection device and a current transformer according to an exemplary embodiment, as shown below. Figure 3 As shown, the connection module 200 includes a first connection module and a second connection module. The first connection module is used to electrically connect the secondary junction box of the current transformer and the relay module 401 outside the detection device to realize the switching of different current transformer windings. The second connection module is used to electrically connect the switch terminal box and the detection module 300 to realize the detection of the secondary load of each current transformer winding. It should be noted that both the first and second connection modules include several terminals, and two adjacent terminals form a group of wiring units. Any group of wiring units is connected to the winding of the current transformer.

[0028] Figure 4 This is a schematic diagram of a detection device for the secondary load of a current transformer, according to another exemplary embodiment, such as... Figure 4 As shown, the detection module 300 in the detection device includes an automatic calibration module 301, a current output module 302, and a voltage acquisition module 303.

[0029] The current output module 302 is electrically connected to the connection module 200 and the automatic verification module 301, and is used to output rated current to the connection module 200. The voltage acquisition module 303 is electrically connected to the connection module 200 and the automatic verification module 301, and is used to acquire the voltage of the connection module 200. The automatic verification module 301 is electrically connected to the main control module 100, and is used to sequentially control the rated current output module 302 to output current, and the voltage acquisition module 303 to acquire voltage.

[0030] The current output module 302 uses a constant current source with an output current range of 1A to 5A, which can meet the load testing requirements of current transformers of different specifications. In addition, the constant current source also has an overcurrent protection function to prevent overload caused by circuit abnormalities, which could damage the constant current source.

[0031] The voltage acquisition module 303 uses an ADC sampling chip. The sampling frequency is adjusted according to the actual application scenario. The ADC sampling chip can suppress electromagnetic interference in the substation and accurately acquire voltage differences in the secondary circuit, providing reliable voltage acquisition data. Optionally, the ADC sampling chip has a sampling accuracy of 0.01V and a sampling frequency of 10 times / second.

[0032] The automatic verification module 301 is equivalent to a sub-control module of the main control module 100. It is used to control the order of the current output module 302 and the voltage acquisition module 303 so that the detection module 300 can meet the correct detection logic.

[0033] The automatic calibration module 301 in the detection module 300 first controls the current output module 301 to output the rated current to the connection module 200, so as to realize the output of the rated current in the secondary circuit of the current transformer. Then, the voltage acquisition module 303 accurately acquires the voltage in the secondary circuit. The automatic calibration module 301 transmits the acquired voltage and the output rated current to the main control module 100, and the main control module 100 realizes the detection of the secondary load.

[0034] Figure 5 This is a schematic diagram of a main control module according to an exemplary embodiment, such as... Figure 5 As shown, the main control module 100 includes: a main control module 101, electrically connected to the automatic verification module 301 for acquiring test results, and electrically connected to the loop switching module 400 for transmitting switching commands to the loop switching module 400; an instruction module 102 for transmitting control commands, including a button unit 11 and a storage unit 12; the button unit 11, electrically connected to the main control module 101, for inputting control commands and determining the rated current; and the storage unit 12, electrically connected to the main control module 101, for storing the verification scheme and test results; a display module 103, electrically connected to the main control module 101, for displaying the test results; and a generation module 104, electrically connected to the main control module 101, for generating an inspection report.

[0035] The main control module 101 is an industrial-grade MCU chip. Therefore, the main control module 101 has the characteristics of fast processing speed and strong anti-electromagnetic interference capability, and can quickly parse instructions, perform data operations, and coordinate between various modules.

[0036] The instruction module 102 includes a button unit 11 and a storage unit 12. The button unit 11 includes a keypad, enabling parameter input, command issuance, and mode switching. Parameter input can be the rated current of the detection module 300. The storage unit 12 includes a storage chip, characterized by fast read / write speeds and stable data storage. The storage chip can store massive amounts of test data, verification schemes, historical test reports, and test results, effectively ensuring data security. The button unit 11 and the storage unit 12 together constitute the instruction module 102. The button unit 11 determines the rated current through the keypad input, and the storage unit stores the rated current and verification scheme to output control commands to the main control module 101. The verification scheme refers to the collaborative operation mode between various modules.

[0037] The display module 103 includes a high-definition backlit screen, which can clearly display the inspection status of the current transformer, real-time inspection data, fault information of the current transformer, and test report content. It can adapt to complex visual environments such as strong light and weak light in substations. Furthermore, the display module 103 and the button unit 11 can form a human-machine interaction system. Inspectors can input parameters and issue commands through the button unit, and the display module 103 can provide inspectors with a visual display of results, thereby enabling them to intuitively determine the relationship between input and inspection results and improving inspection efficiency.

[0038] The generation module 104 is used to generate a test report on the secondary load test of the current transformer based on each test result.

[0039] Figure 6 This is a schematic diagram of the main control module according to another exemplary embodiment, such as... Figure 6 As shown, the main control module 100 also includes a USB interface 105, electrically connected to the main control module 101, for exporting inspection reports. The USB interface 105 serves as the information interface between the testing device and external systems, enabling rapid export of PDF format inspection reports for easy data archiving and subsequent analysis by testing personnel. Optionally, the USB interface 105 has a transmission rate of 480 Mbps.

[0040] Figure 7 This is a schematic diagram of a detection device for the secondary load of a current transformer, according to another exemplary embodiment, such as... Figure 7 As shown, the detection device also includes a battery module 500, which is electrically connected to the main control module 100. The battery module 500 includes a charge / discharge module 51, a lithium battery 53, and a converter 52. The charge / discharge module 51 is electrically connected to the lithium battery 53 and the converter 52, and the converter 52 is electrically connected to the main control module 100.

[0041] The inverter 52 features bidirectional conversion and wide voltage adaptation. When an external 220V±10%, 50Hz AC power supply is connected to the inverter 52, the battery module 500 operates in AC-DC rectification mode, converting the AC power into DC power to provide a stable DC current to each module and unit in the detection device, ensuring stable operation. Furthermore, the inverter 52 also charges the lithium battery 53 through the charge / discharge module 51. The charge / discharge module 51 is equipped with overcharge, over-discharge, and over-temperature protection mechanisms to ensure the safe charging and discharging of the lithium battery 53. The lithium battery 53 serves to switch the AC-DC rectification mode to DC-DC boost / buck mode via the inverter 51 when the external current suddenly stops, accurately converting the 12V DC power from the lithium battery 53 into the operating current required by each module and unit, thus ensuring the stable and continuous operation of the detection device.

[0042] The testing device in this application integrates all internal modules and components. For testing personnel, the testing device can be controlled through its control panel. Figure 8 This is a schematic diagram illustrating the control panel of the detection device according to an exemplary embodiment, such as... Figure 8 As shown, the control panel 600 includes a first wiring module 1, a second wiring module 2, a USB interface 105, a display module 103, a button unit 11, a three-hole socket 3, a rocker switch 4, and a grounding contact 5.

[0043] The connection module 200 includes a first connection module 1 and a second connection module 2. Both the first connection module 1 and the second connection module 2 have the same number of connection posts. Adjacent connection posts constitute a connection unit, and each connection post belongs to only one connection unit. It should be noted that the first connection unit of the first connection module 1 and the second connection unit of the second connection module 2 correspond one-to-one. Figure 9 This is a schematic diagram illustrating the terminals according to an exemplary embodiment, such as... Figure 9 As shown, both the first wiring module 1 and the second wiring module 2 use rotatable and detachable terminals, allowing testing personnel to connect and disconnect the testing device and the current transformer by connecting and disconnecting the terminals. The first wiring module 1 is used to electrically connect to the secondary junction box of the current transformer. The circuit switching module 400 controls the relay 41 to engage and disengage internally, thus connecting and disconnecting the current transformer. The second wiring module 2 is used to electrically connect to the switch terminal box. The current output module 302 is electrically connected to the second wiring module 2, injecting current into the external circuit. The voltage acquisition module 303 acquires the voltage from the second wiring module 2.

[0044] The USB interface 105 is used by the inspector to export the test results and report after the test is completed. The display module 103 displays the test results and calibration report, and, in conjunction with the button unit 11, allows the user to set test information, such as setting the rated current. The button unit 11 is used to input commands to the inspector and, in conjunction with the display module 103, forms a human-machine interface.

[0045] The three-hole socket 3 is used to connect an external power source to power the testing device and charge the lithium battery. The rocker switch 4 is used to control the on / off state of the power supply to the entire testing device. The grounding contact 5 is used to connect to the grounding copper busbar of the substation switch terminal box or cabinet to bring the casing or reference ground of the testing device to the same potential level as the ground potential of the substation equipment, avoiding a voltage difference between the two and ensuring the personal safety of the testing personnel and the safety of the testing device.

[0046] In summary, the detection device for the secondary load of a current transformer provided in this application connects the detection device to the secondary circuit of the current transformer via a connection module 200. The connection is controlled by a main control module 100 which sends control commands to the relay module 401 in the control circuit switching module 400. Different windings are switched, and the rated current is applied to the connection module via a current output module 302. A voltage acquisition module 303 acquires the voltage of the connection module, and the detection results for each winding are obtained in the main control module 100. The detection device connects before detection and, during detection, controls the switching of different relay modules 401 via the main control module 100 to apply rated current and acquire voltage to different windings, enabling rapid detection of different windings. The detection device connects to the current transformer before detection and disconnects after detection. It automatically switches windings and performs detection during the process, enabling detection of each winding. This reduces the number of times personnel need to climb and the workload of rewiring when switching different windings, thereby improving the efficiency of detecting the secondary load of the current transformer.

[0047] Secondly, embodiments of this application provide a method for detecting the secondary load of a current transformer. Figure 10 This is a flowchart illustrating a method for detecting the secondary load of a current transformer according to an exemplary embodiment, such as... Figure 2 As shown, the detection method for the secondary load of a current transformer is applied to the detection device of the first aspect, and the method includes: Step S101: Obtain control commands and rated current. For the current transformer winding, the main control module responds to the control commands, and the relay in the control circuit switching module is activated.

[0048] The testing personnel input the rated current of the current transformer being tested via the button unit on the control panel. The testing device obtains the rated current and receives control commands through the verification scheme stored in the storage unit. These control commands include not only the coordination steps between modules and groups but also the rated current obtained from the button unit.

[0049] For the winding of the current transformer, the main control module responds to the control command by synchronously sending start commands to the circuit switching module, current output module, and voltage acquisition module. Once all three modules are started, the main control module synchronously sends control signals to the control units in each relay module of the circuit switching module to activate the relay of the currently detected winding and deactivate the others. Upon receiving the control signal, the control unit in each relay module determines the appropriate state for the current relay module and sends a level signal to the relay to control its opening and closing. Specifically, if the relay module should be closed, a high-level signal is sent; otherwise, a low-level signal is sent.

[0050] If the control signal received by the control unit is a closed signal, indicating that the relay module should be in a closed state, a high-level signal is sent to the relay. Upon receiving the high-level signal, the relay contacts close, connecting the secondary junction box of the current transformer connected to the relay. If the control signal received by the control unit is an open signal, indicating that the relay module should be in a closed state, a low-level signal is sent to the relay. Upon receiving the low-level signal, the relay contacts open, disconnecting the secondary junction box of the current transformer connected to the relay.

[0051] In one embodiment, Figure 11 This is a schematic diagram of a loop connection according to an exemplary embodiment, such as... Figure 11 As shown, the current transformer has six windings, and the secondary junction box of the current transformer includes connection points for the secondary circuit of each winding. The main control module sends control signals to each control unit, sending a closing signal for the first winding A1A1' and an opening signal for the remaining windings. The secondary circuit of the first winding is connected by the relay module. It also controls the current output module to output current to winding A1A1' in the switch terminal box through the wiring module, and the voltage acquisition module to acquire voltage from winding A1A1' in the switch terminal box through the wiring module.

[0052] The relay module is connected to the secondary junction box of the current transformer. The main control module controls multiple relays, enabling a single relay to engage while the others disengage. This allows for testing of only the winding of a single current transformer, thus completing a single test.

[0053] Step S102, Detection Step: When the relay is energized, the main control module controls the detection module to output the rated current to the connected module and obtains the voltage of the connected module. Based on the voltage and rated current, the load power is obtained, and the load power is compared with the preset load power to obtain the detection result.

[0054] When the relay is energized, the secondary circuit of the current transformer winding is activated. The main control module controls the detection module to output rated current to the connected module and then receives voltage from the connected module. Based on the output rated current and the received voltage, the main control module calculates the load power of the secondary circuit according to a preset formula. The load power is compared with the preset load power to obtain the detection result. The detection result includes whether the current winding load is unqualified or qualified. If the load power is less than or equal to the preset load power, the current winding load is qualified. If the load power is greater than the preset load power, the current winding load is unqualified. The preset load power is stored in the verification scheme and is a value that ensures the safe operation of the secondary circuit. The preset formula is a power calculation formula that specifically satisfies P=I0. A,A’ *U A,A’ P is the load power, I A,A’ It is the rated current applied to the A,A' winding circuit, U A,A’ The voltage difference measured at terminals A1 and A1' in the wiring unit is obtained through the voltage acquisition module.

[0055] More specifically, when the relay is energized, the main control module controls the detection module to output the rated current to the connected module and obtain the voltage of the connected module. This is specifically achieved by the automatic verification module, voltage acquisition module and current output module in the detection module.

[0056] When the relay is energized, it connects to the winding of the current transformer. The main control module sends a control command to the automatic verification module. Responding to the control command, the automatic verification module sequentially controls the current output module to output rated current to the connected module and the voltage acquisition module to acquire the voltage of the connected module. The voltage acquired by the voltage acquisition module is transmitted to the automatic verification module for voltage acquisition. Based on the current output rated current and acquired voltage, the automatic verification module transmits both data to the main control module for subsequent load power calculation. The voltage acquisition module acquires the voltage difference at a frequency of 10 times / second, using the average value within a preset time period as the valid voltage data. The preset time period includes 1 minute and 2 minutes.

[0057] In one embodiment, the preset load power is 30VA. The load power of the secondary circuit is obtained through a preset calculation formula. The rated current of a conventional substation is 5A. Therefore, by setting the input rated current to 5A, a 5A current is output through the current output module. The voltage difference at the terminals is collected by the voltage acquisition module, and the voltage is obtained as 6V. Then, the load power P=I is calculated using the preset formula. A,A’ *U A,A’ The load power is 30VA. The load power is compared with the preset load power. If they are equal, the test result is that the current winding load is qualified.

[0058] Controlled by the main control module, the current output module outputs current and the voltage acquisition module acquires voltage. The main control module obtains the load power of the secondary circuit of the current transformer's current winding, thus enabling a single detection of the secondary circuit of the current transformer.

[0059] Step S103: Based on the detection results, the main control module sends a switching command to the circuit switching module. In response to the switching command, the circuit switching module engages the relay of the next winding and executes the detection steps again to obtain the detection results of the next winding until all windings are detected.

[0060] After a single test is completed, i.e., after the main control module obtains the test result, it sends a closing signal to the loop switching module to disconnect all relays. After waiting for a preset delay, the main control module sends a loop switching command to the loop switching module, closing the relays of the next winding of the current transformer and repeating the test steps. Specifically, the current output module outputs the rated current, the voltage acquisition module acquires the voltage, and the load power of the currently tested winding is determined based on the rated current and voltage. These values ​​are then compared to obtain the test result. The switching command is used to perform the test on each winding until all windings are tested. The preset delay time ensures that all relays are in the open state; the specific value of the preset delay time can be set according to actual conditions, such as 50ms or 1s. Optionally, the closing and opening signals in the control signals can be represented by identifiers and their corresponding values. For example, if the identifier is f, f=1 represents a closing signal, and f=0 represents an opening signal.

[0061] Figure 12 This is a schematic diagram illustrating loop switching according to an exemplary embodiment, such as... Figure 12As shown, the current transformer has six windings: A1 and A1' are the first winding, A2 and A2' are the second winding, A3 and A3' are the third winding, A4 and A4' are the fourth winding, A5 and A5' are the fifth winding, and A6 and A6' are the sixth winding. Each winding is connected to a connection unit: the first winding is connected to the first connection unit, the second winding to the second connection unit, the third winding to the third connection unit, the fourth winding to the fourth connection unit, the fifth winding to the fifth connection unit, and the sixth winding to the sixth connection unit. When the main control module sends a control signal to the circuit switching module, the relay in the first connection unit receives a high-level signal and turns on the secondary circuit of the first winding; the relays in other connection units receive a low-level signal and disconnect the secondary circuits of other windings, so that only the load power of the secondary circuit of the first winding is detected. When the main control module sends a switching command to the circuit switching module, the relay in the second connection unit receives a high-level signal to turn on the secondary circuit of the second winding, and the relays in other connection units receive a low-level signal to disconnect the secondary circuits of other windings, so as to detect only the load power of the secondary circuit of the second winding.

[0062] Each test result from the testing device, including the output rated current and the collected voltage, is stored in the storage unit. After completing the testing of all windings in the current transformer, the main control module retrieves the test data of each winding from the storage unit and organizes it into a test dataset according to a standard format. The standardized format includes the test date, the current transformer model, rated parameters, the tested current, voltage, load power, and test results for each winding, with unqualified windings marked with an abnormality label.

[0063] The main control module converts the test dataset into an inspection report through the generation module and synchronizes the inspection report to the display module for review by the testing personnel. Testing personnel can also export the inspection report via USB interface for subsequent troubleshooting.

[0064] Before testing, the testing personnel turn on the rocker switch of the testing device. The main control module automatically starts the full system self-test mode, verifying the on / off status of each relay contact in the circuit switching module, the load capacity of the current output module, the accuracy of the voltage acquisition module, the read / write function of the storage unit, and the stability of the lithium battery and power supply circuit. The self-test results are displayed in real time on the display module. If any module has a fault, a pop-up window will display the corresponding fault code and troubleshooting direction for the testing personnel to troubleshoot. After the testing device passes the self-test, the windings of the current transformer are then tested to prevent fault testing.

[0065] It should be noted that if abnormal current output, voltage acquisition failure, or relay switching malfunction occurs during the testing process, an abnormal signal will be sent to the main control module. Upon receiving the abnormal signal, the main control module of the testing device will cut off the current output of the current output module, issue an alarm, and record the fault information. After the testing personnel troubleshoot the fault, they can restart the testing device, which can then resume testing from the interrupted winding.

[0066] In summary, this application provides a method for detecting the secondary load of a current transformer. The testing personnel connect to the current transformer via a testing device. The main control module automatically switches the relay engagement according to control commands, enabling automatic testing of different windings. During a single test, the rated current is output through the current output module, the voltage acquisition module acquires the voltage, and the main control module calculates the load power of the secondary circuit of the tested winding. The load power is then compared with a preset load power to obtain the test result. This allows for automatic testing without manual intervention during the switching and testing processes. The testing is achieved automatically through the coordination of various modules within the testing device, reducing the workload of testing personnel and the need for repeated disassembly and wiring, thus improving the testing efficiency of current transformers.

[0067] It should be noted that the implementation methods described above will not be repeated hereafter. As used above, terms such as "module," "unit," and "subunit" can refer to combinations of software and / or hardware that perform a predetermined function. Although the apparatus described in the above embodiments is preferably implemented in software, hardware implementation, or a combination of software and hardware, is also possible and contemplated.

[0068] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0069] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A detection device for the secondary load of a current transformer, characterized in that, include: Main control module, detection module, loop switching module, and connection module; The main control module is electrically connected to the detection module and the loop switching module, and is used to send control commands and obtain detection results; The connection module is electrically connected to the secondary junction box and switch terminal box of the current transformer, and is also electrically connected to the detection module and the circuit switching module; The detection module is used to apply a rated current to the connection module and to acquire the voltage of the connection module; The circuit switching module includes at least two relay modules. Each relay module is electrically connected to a winding of a current transformer. Each relay module includes a relay, a drive circuit, and a control unit. The relay is electrically connected to the drive circuit and the connection module. The control unit is electrically connected to the drive circuit and the main control module, and is used to receive switching commands from the main control module and control the on / off state of the relay.

2. The detection device for the secondary load of a current transformer according to claim 1, characterized in that, The detection module includes: a current output module, a voltage acquisition module, and an automatic verification module; The current output module is electrically connected to the connection module and the automatic verification module, and is used to output the rated current to the connection module; A voltage acquisition module is electrically connected to the connection module and the automatic verification module, and is used to acquire the voltage of the connection module; An automatic verification module, electrically connected to the main control module, is used to sequentially control the rated current output module to output current, and the voltage acquisition module to acquire the voltage.

3. The detection device for the secondary load of a current transformer according to claim 2, characterized in that, The main control module includes: The main control module is electrically connected to the automatic verification module for acquiring the detection results and electrically connected to the loop switching module for transmitting switching commands to the loop switching module. The instruction module is used to transmit control instructions. The instruction module includes a button unit and a storage unit. The button unit is electrically connected to the main control module and is used to input the control instructions and determine the rated current. The storage unit is electrically connected to the main control module and is used to store the verification scheme and the detection results. The display module is electrically connected to the main control module and is used to display the detection results; The generation module, electrically connected to the main control module, is used to generate inspection reports.

4. The detection device for the secondary load of a current transformer according to claim 3, characterized in that, The main control module also includes: The USB interface is electrically connected to the main control module and is used to export the inspection report.

5. The detection device for the secondary load of a current transformer according to claim 1, characterized in that, The device further includes: A battery module is electrically connected to the main control module. The battery module includes a charging / discharging module, a lithium battery, and a converter. The charging / discharging module is electrically connected to the battery and the converter, and the converter is electrically connected to the main control module.

6. A method for detecting the secondary load of a current transformer, characterized in that, A detection device applied to the secondary load of any one of current transformers (items 1-5), the method comprising: Upon acquiring control commands and rated current, and in response to the control commands for the current transformer winding, the main control module activates the relays in the control loop switching module. Detection steps: When the relay is energized, the main control module controls the detection module to output the rated current to the connected module and obtains the voltage of the connected module. Based on the voltage and the rated current, the load power is obtained. The load power is compared with the preset load power to obtain the detection result. Based on the detection results, the main control module sends a switching command to the circuit switching module. In response to the switching command, the circuit switching module engages the relay of the next winding and executes the detection steps again to obtain the detection results of the next winding until all windings have been detected.

7. The detection method for the secondary load of a current transformer according to claim 6, characterized in that, The step of comparing the load power with the preset load power to obtain the detection result includes: Compare the load power with the preset load power. If the load power is less than the preset load power, then the current winding load is qualified. If the load power is greater than or equal to the preset load power, then the current winding load is unqualified.

8. The detection method for the secondary load of a current transformer according to claim 6, characterized in that, Regarding the winding of the current transformer, the main control module responds to a control command, and the relay in the control circuit switching module engages, including: For the winding of the current transformer, the main control module responds to the control command and controls the control unit in the circuit switching module to transmit a level signal to the relay; If the level signal is a high level signal, the relay responds to the high level signal and activates the relay contacts; If the control signal is a low-level signal, the relay responds to the low-level signal by disconnecting the relay contacts.

9. The detection method for the secondary load of a current transformer according to claim 8, characterized in that, When the relay is energized, the main control module controls the detection module to output the rated current to the connection module and obtains the voltage of the connection module, including: The main control module sends the control command to the automatic verification module. In response to the control command, the automatic verification module sequentially controls the current output module to output the rated current to the connection module. The voltage acquisition module acquires the voltage of the connection module and obtains the voltage in the automatic verification module.

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