Rapid testing device for characteristics of current transformer

Abstract

The invention discloses a rapid testing device for characteristics of a current transformer, relates to the technical field of current transformer testing, and solves the problems that traditional detection needs high-voltage source support, equipment is complex and tedious to operate and is not suitable for on-site rapid detection. The state of the current transformer can be monitored in real time, and a short circuit event can be found and responded in time. According to the detection device, the excitation signal detection magnetic ring and the feedback signal output magnetic ring are coupled with the primary current input line of the second CT, so that the anti-interference performance is improved. On the excitation signal detection magnetic ring side, an excitation signal generated by an excitation signal generator is coupled to a CT primary current input line through a magnetic ring after being conditioned, and a feedback signal is output through a feedback signal output magnetic ring. The non-contact detection method not only improves the stability of the system, but also avoids the risk possibly brought by direct electrical connection, and ensures the safe and stable operation of the power system.

Description

Technical Field

[0001] The invention relates to the technical field of current transformer testing, and in particular to a current transformer characteristic rapid testing device. Background Art

[0002] During the operation and maintenance of the power system, the current transformer (CT) is a key measurement and protection device, and the accuracy of its performance directly affects the safe and stable operation of the system. The short circuit problem on the secondary side of the CT is a common fault in the power system. This fault not only affects the normal measurement and protection functions of the power system, but also may cause the protection device to malfunction or refuse to operate, thus bringing serious safety hazards. Traditional CT detection methods often rely on complex and large test equipment, which not only increases the operating burden of on-site staff, but also is inconvenient to use in non-acceptance, first inspection, scheduled inspection or other power outage work. In addition, for the judgment of CT level, the traditional method also lacks a fast and accurate means. These factors limit the efficiency and accuracy of power system maintenance work. For the detection of CT secondary side short circuit faults, the current mainstream technology in China relies on traditional large-scale test instruments, such as electrical comprehensive testers and CT volt-ampere characteristic testers. Although these devices have high measurement accuracy, they are complex to operate and bulky, and usually require power outage conditions for detection, which limits their application in unplanned maintenance and rapid detection scenarios. In addition, some research institutions and enterprises have developed simplified detection methods based on impedance testing or inductance measurement for fault diagnosis problems, but most of them remain in the theoretical verification stage and have not yet been widely promoted, and the detection efficiency and anti-interference capabilities still need to be optimized.

[0003] In terms of CT level judgment, the traditional method mainly relies on the measurement of the volt-ampere characteristic curve to determine the performance difference between the P-level winding for protection and the S-level winding for measurement and metering. However, this method usually requires high-voltage source support, the equipment is complex and the operation is cumbersome, and it is not suitable for rapid on-site detection. In recent years, some studies have proposed CT characteristic analysis methods based on low-voltage input, which make level judgments by applying small currents or signals, but there is still room for improvement in detection accuracy and applicability.

[0004] In view of this, a device for quickly testing the characteristics of a current transformer is needed. Summary of the invention

[0005] In view of the problem that traditional detection requires high-voltage source support, the equipment is complex and the operation is cumbersome, and it is not suitable for rapid on-site detection, the present invention provides a current transformer characteristic rapid test device, which can connect the test device with the current transformer under test to ensure that the connection is correct and reliable, and then effectively judge the state of the CT secondary side based on the voltage value of the test feedback signal, and feedback to the user through the alarm module and display screen. This process ensures the real-time monitoring and response capabilities of the system. The specific technical solution is as follows:

[0006] A device for quickly testing characteristics of a current transformer comprises a current transformer module, an excitation signal generator module, a feedback signal sampler, a microcontroller module, a display module and a power module, wherein the power module is respectively connected to the current transformer module, the feedback signal sampler, the excitation signal generator module, the microcontroller module and the display module, the microcontroller module is respectively connected to the display module, the feedback signal sampler and the current transformer module, and the current transformer module is connected to the excitation signal generator module; the current transformer module is used to test the current in the circuit, the excitation signal generator is used to generate a high-frequency square wave excitation signal, the feedback signal sampler adopts a metering chip to complete the sampling of the feedback signal, the microcontroller module collects ADC data, executes an algorithm to determine the secondary side state of the CT, and controls the display screen module.

[0007] Preferably, it further comprises an excitation signal conditioning unit connected to the excitation signal generator, and the excitation signal conditioning unit conditions the excitation signal to adapt to the input requirement of the CT.

[0008] Preferably, it also includes an excitation signal detection magnetic ring, which is connected to the excitation signal generator and the excitation signal conditioning unit. The excitation signal detection magnetic ring is used to couple the excitation signal to the secondary side of the CT, and the signal generated by the excitation signal generator is transmitted to the secondary side of the CT through the excitation signal detection magnetic ring.

[0009] Preferably, it further comprises a feedback signal conditioning and limiting unit, which limits, high-pass filters and differentially modulates the signal fed back from the secondary side of the CT, and is connected to the feedback signal sampler.

[0010] Preferably, it also includes a feedback signal output magnetic ring, which is located between the secondary side of the CT and the feedback signal conditioning and limiting unit. The feedback signal output magnetic ring is used to obtain a feedback signal from the secondary side of the CT. When the excitation signal generates a current on the secondary side of the CT, any changes caused by a short circuit or an open circuit will appear in the form of a feedback signal. The feedback signal output magnetic ring transmits the changes caused by the short circuit or the open circuit back to the feedback signal conditioning and limiting unit of the system for further processing.

[0011] Preferably, it also includes an alarm module, which is connected to the microcontroller module and is used for providing an audible and visual alarm after receiving an alarm signal.

[0012] Preferably, it also includes a step-down module, which is connected between the power supply module and the current transformer module, the feedback signal sampler, the excitation signal generator module, the microcontroller module and the display module, and the step-down module reduces the power supply voltage to a working level that matches the microcontroller and other unit modules.

[0013] Preferably, the microcontroller module processes the collected data and controls the alarm module and the display screen through the following steps:

[0014] S1: The feedback signal amplitude obtained from the feedback signal sampler. The voltage value of the feedback signal is read using the ADC module and converted into a current value. The calculation formula is as follows:

[0015]

[0016] Where Current(A) is the calculated current value in amperes (A); ADC_Value is the digital value read from the ADC module, which usually ranges from 0 to 4095. ref It represents the reference voltage of the ADC module, in volts (V); β is the resolution of the ADC, δ represents the offset voltage, in volts (V); Sensitivity represents the sensitivity of the current sensor, in volts per ampere (V / A);

[0017] S2: Set thresholds, including short-circuit thresholds and normal working thresholds, and compare the calculated current value with the thresholds: if the current value is greater than the short-circuit threshold, it is determined to be a short-circuit state; if the current value is within the normal working threshold range, it is determined to be a normal state; if the current value is close to zero, it is determined to be an open circuit state;

[0018] S3: When a short circuit is detected, the STM32 will trigger the alarm module and issue an audible and visual alarm.

[0019] S4: Real-time display of current value and status information, including "normal", "short circuit" and "open circuit".

[0020] A computer-readable storage medium, the computer-readable storage medium comprising a stored program, wherein when the program is executed, the device where the computer-readable storage medium is located is controlled to execute the control method of the microcontroller module according to claim 8.

[0021] A processor, the processor is used to run a program, wherein the control method of the microcontroller module according to claim 8 is executed when the program is run.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1. The present invention can monitor the status of the current transformer in real time, and promptly detect and respond to short-circuit events. This detection device couples the second CT primary current input line through the excitation signal detection magnetic ring and the feedback signal output magnetic ring, thereby improving the anti-interference performance. On the excitation signal detection magnetic ring side, the excitation signal generated by the excitation signal generator is conditioned and coupled to the CT primary current input line through the magnetic ring, while the feedback signal is output through the feedback signal output magnetic ring. This non-contact detection method not only improves the stability of the system, but also avoids the risks that may be caused by direct electrical connection, ensuring the safe and stable operation of the power system.

[0024] 2. The present invention uses an excitation signal detection magnetic ring at the output end of the excitation signal conditioning unit to couple to the CT primary current input line, and outputs a feedback signal through a feedback signal output magnetic ring, so that the system can effectively suppress external interference and ensure the purity of the signal. In addition, the feedback signal is limited, high-pass filtered and differentially modulated in the conditioning limiting unit. These processing steps further enhance the signal's anti-interference ability and improve the measurement accuracy, so that the system can accurately detect the state of the CT secondary side in a complex power system.

[0025] 3. The high integration and programmability of the microcontroller provided in the present invention enable the system to be programmed according to specific application scenarios to achieve various control and monitoring functions. The system collects ADC data in real time through the microcontroller, executes the algorithm to determine the status of the CT secondary side, and controls the alarm module and display screen. This real-time monitoring and rapid response mechanism ensures that once a short circuit or other abnormal situation is detected, the system can immediately take measures, such as triggering the alarm module to issue a voice alarm and displaying a warning message on the display screen, thereby greatly shortening the fault response time and improving the real-time performance and reliability of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for the specific embodiments or the description of the prior art. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn according to the actual scale.

[0027] Figure 1 It is a schematic diagram of the overall framework of the present invention;

[0028] Figure 2It is the microcontroller control flow chart of the present invention. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] It should be understood that when used in this specification and the appended claims, the terms "include" and "comprises" indicate the presence of described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0031] It should also be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, the singular forms "a", "an" and "the" are intended to include plural forms unless the context clearly indicates otherwise.

[0032] It should be further understood that the term "and / or" used in the present description and the appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0033] In one embodiment of the present invention, a current transformer characteristic rapid testing device is provided, which is a comprehensive detection system, such as Figure 1 As shown, it introduces a second CT (current transformer) to detect whether the secondary side of the CT to be detected is in an open-short circuit state. The specific implementation process is as follows:

[0034] Excitation signal generator: First, the system uses the excitation signal generator to generate an excitation signal. This signal is a high-frequency square wave, which ensures the detection response speed.

[0035] Excitation signal conditioning unit: The excitation signal is then transmitted to the excitation signal conditioning unit for conditioning to adapt to subsequent circuit requirements.

[0036] Excitation signal detection magnetic ring: The conditioned excitation signal is coupled to the primary current input line of the second CT through the excitation signal detection magnetic ring. The core of this magnetic ring is made of ferrite material to improve the coupling efficiency.

[0037] Feedback signal output magnetic ring: The primary current input line of the second CT outputs the feedback signal through the feedback signal output magnetic ring. This magnetic ring uses amorphous material to optimize signal transmission.

[0038] Feedback signal conditioning and limiting unit: The feedback signal is input into the feedback signal conditioning and limiting unit for limiting, high-pass filtering and differential modulation to ensure signal stability and accuracy.

[0039] Feedback signal sampler: The processed feedback signal is finally output to the feedback signal sampler, which collects the feedback signal amplitude.

[0040] Microcontroller (control module): The microcontroller reads the amplitude of the feedback signal collected by the sampler, and determines the open-circuit or short-circuit state of the secondary side of the CT to be detected through algorithm analysis.

[0041] Display screen and alarm module: The microcontroller controls the display screen to display the real-time collected information and processed information according to the judgment result. If it is judged as a short circuit, a red exclamation mark will appear on the display screen, and the alarm module will issue a voice alarm.

[0042] The specific implementation functions of each module or unit are as follows:

[0043] Excitation signal generator: responsible for generating the excitation signal used for detection and is the starting point of the detection process.

[0044] Excitation signal conditioning unit: Conditions the excitation signal to ensure that the signal does not affect the analog measurement signal of the metering loop during transmission.

[0045] Excitation signal detection magnetic ring: As a medium for signal transmission, it couples the conditioned excitation signal to the primary current input line of the second CT.

[0046] Feedback signal output magnetic ring: Output feedback signal from the primary current input line of the second CT as the basis for the detection result.

[0047] Feedback signal conditioning and limiting unit: further processes the feedback signal, including limiting, high-pass filtering and differential modulation, to improve signal quality.

[0048] Feedback signal sampler: collects the amplitude of the processed feedback signal to provide a basis for the microcontroller to make decisions.

[0049] Microcontroller (control module): The core processing unit reads the data from the sampler, executes the algorithm to determine the status of the CT secondary side, and controls the alarm module and display screen.

[0050] Display screen: Displays collected and processed information in real time, providing intuitive feedback to users.

[0051] Alarm module: When a short circuit is detected, a voice alarm is issued to remind the user to take appropriate measures.

[0052] In detail, the current transformer characteristic rapid testing device described in this embodiment includes a current transformer module, an excitation signal generator module, a feedback signal sampler, a microcontroller module, a display module and a power supply module, wherein the power supply module is respectively connected to the current transformer module, the feedback signal sampler, the excitation signal generator module, the microcontroller module and the display module, the microcontroller module is respectively connected to the display module, the feedback signal sampler and the current transformer module, and the current transformer module is connected to the excitation signal generator module; the current transformer module is used to test the current in the circuit, the excitation signal generator is used to generate a high-frequency square wave excitation signal, the feedback signal sampler adopts a metering chip to complete the sampling of the feedback signal, the microcontroller module collects ADC data, executes an algorithm to determine the secondary side state of the CT, and controls the display screen module.

[0053] The excitation signal conditioning unit is connected to the excitation signal generator, and the excitation signal conditioning unit conditions the excitation signal to adapt to the input requirements of the CT. The excitation signal detection magnetic ring is connected to the excitation signal generator and the excitation signal conditioning unit, and the excitation signal detection magnetic ring is used to couple the excitation signal to the secondary side of the CT. The signal generated by the excitation signal generator is transmitted to the secondary side of the CT through the excitation signal detection magnetic ring.

[0054] The feedback signal conditioning and limiting unit performs limiting, high-pass filtering and differential modulation on the signal fed back from the secondary side of the CT, and the feedback signal conditioning and limiting unit is connected to the feedback signal sampler. The feedback signal output magnetic ring is located between the secondary side of the CT and the feedback signal conditioning and limiting unit. The feedback signal output magnetic ring is used to obtain the feedback signal from the secondary side of the CT. When the excitation signal generates current on the secondary side of the CT, any changes caused by short circuit or open circuit will appear in the form of feedback signal. The feedback signal output magnetic ring transmits the changes caused by short circuit or open circuit back to the feedback signal conditioning and limiting unit of the system for further processing.

[0055] The alarm module is connected to the microcontroller module and is used for providing sound and light alarm after receiving the alarm signal.

[0056] The step-down module is connected between the power module and the current transformer module, the feedback signal sampler, the excitation signal generator module, the microcontroller module and the display module, and the step-down module reduces the power supply voltage to a working level that matches the microcontroller and other unit modules.

[0057] like Figure 2As shown, the microcontroller module will process the collected data and control the alarm module and display screen through the following steps:

[0058] S1: The feedback signal amplitude obtained from the feedback signal sampler. The voltage value of the feedback signal is read using the ADC module and converted into a current value. The calculation formula is as follows:

[0059]

[0060] Where Current(A) is the calculated current value in amperes (A); ADC_Value is the digital value read from the ADC module, which usually ranges from 0 to 4095. ref It represents the reference voltage of the ADC module, in volts (V); β is the resolution of the ADC, δ represents the offset voltage, in volts (V); Sensitivity represents the sensitivity of the current sensor, in volts per ampere (V / A);

[0061] S2: Set thresholds, including short-circuit thresholds and normal working thresholds, and compare the calculated current value with the thresholds: if the current value is greater than the short-circuit threshold, it is determined to be a short-circuit state; if the current value is within the normal working threshold range, it is determined to be a normal state; if the current value is close to zero, it is determined to be an open circuit state;

[0062] S3: When a short circuit is detected, the STM32 will trigger the alarm module and issue an audible and visual alarm.

[0063] S4: Real-time display of current value and status information, including "normal", "short circuit" and "open circuit".

[0064] In summary, the present invention can monitor the state of the current transformer in real time, and promptly detect and respond to short-circuit events. This detection device is coupled with the second CT primary current input line through the excitation signal detection magnetic ring and the feedback signal output magnetic ring, thereby improving the anti-interference performance. On the excitation signal detection magnetic ring side, the excitation signal generated by the excitation signal generator is conditioned and coupled to the CT primary current input line through the magnetic ring, while the feedback signal is output through the feedback signal output magnetic ring. This non-contact detection method not only improves the stability of the system, but also avoids the risks that may be caused by direct electrical connection, ensuring the safe and stable operation of the power system. Moreover, the present invention uses the excitation signal detection magnetic ring to couple to the CT primary current input line at the output end of the excitation signal conditioning unit, and outputs the feedback signal through the feedback signal output magnetic ring. The system can effectively suppress external interference and ensure the purity of the signal. In addition, the feedback signal is limited, high-pass filtered and differentially modulated in the conditioning limiting unit. These processing steps further enhance the anti-interference ability of the signal and improve the measurement accuracy, so that the system can accurately detect the state of the CT secondary side in a complex power system. In addition, the high integration and programmability of the microcontroller provided in the present invention enable the system to be programmed according to specific application scenarios to achieve various control and monitoring functions. The system collects ADC data in real time through the microcontroller, executes the algorithm to determine the status of the CT secondary side, and controls the alarm module and display screen. This real-time monitoring and rapid response mechanism ensures that once a short circuit or other abnormal situation is detected, the system can immediately take measures, such as triggering the alarm module to issue a voice alarm and displaying a warning message through the display screen, thereby greatly shortening the fault response time and improving the real-time and reliability of the system.

[0065] Those of ordinary skill in the art will appreciate that the units of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition of each example has been generally described in terms of function in the above description. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0066] In the embodiments provided by the present invention, it should be understood that the division of units is only a logical function division, and there may be other division methods in actual implementation, for example, multiple units can be combined into one unit, one unit can be split into multiple units, or some features can be ignored, etc.

[0067] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0068] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, a server or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, read-only memory (ROM, Read-0nlyMemory), random access memory (RAM, RandomAccessMemory), mobile hard disk, magnetic disk or optical disk, etc., which can store program code.

[0069] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. These modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and specification of the present invention.

Claims

1. A current transformer characteristic rapid testing device, characterized in that: It includes a current transformer module, an excitation signal generator module, a feedback signal sampler, a microcontroller module, a display module and a power supply module. The power supply module is respectively connected to the current transformer module, the feedback signal sampler, the excitation signal generator module, the microcontroller module and the display module. The microcontroller module is respectively connected to the display module, the feedback signal sampler and the current transformer module. The current transformer module is connected to the excitation signal generator module. The current transformer module is used to test the current in the circuit. The excitation signal generator is used to generate a high-frequency square wave excitation signal. The feedback signal sampler adopts a metering chip to complete the sampling of the feedback signal. The microcontroller module collects ADC data, executes an algorithm to determine the secondary side state of the CT, and controls the display screen module.

2. A current transformer characteristic rapid testing device according to claim 1, characterized in that: It also includes an excitation signal conditioning unit connected to the excitation signal generator, and the excitation signal conditioning unit conditions the excitation signal to adapt to the input requirement of the CT.

3. A current transformer characteristic rapid testing device according to claim 2, characterized in that: It also includes an excitation signal detection magnetic ring, which is connected to the excitation signal generator and the excitation signal conditioning unit. The excitation signal detection magnetic ring is used to couple the excitation signal to the secondary side of the CT. The signal generated by the excitation signal generator is transmitted to the secondary side of the CT through the excitation signal detection magnetic ring.

4. A current transformer characteristic rapid testing device according to claim 1, characterized in that: It also includes a feedback signal conditioning and limiting unit, which limits, high-pass filters and differentially modulates the signal fed back from the secondary side of the CT, and is connected to the feedback signal sampler.

5. A current transformer characteristic rapid testing device according to claim 4, characterized in that: It also includes a feedback signal output magnetic ring, which is located between the secondary side of the CT and the feedback signal conditioning and limiting unit. The feedback signal output magnetic ring is used to obtain a feedback signal from the secondary side of the CT. When the excitation signal generates a current on the secondary side of the CT, any changes caused by a short circuit or an open circuit will appear in the form of a feedback signal. The feedback signal output magnetic ring transmits the changes caused by the short circuit or the open circuit back to the feedback signal conditioning and limiting unit of the system for further processing.

6. A current transformer characteristic rapid testing device according to claim 1, characterized in that: It also includes an alarm module, which is connected to the microcontroller module and is used for providing sound and light alarms after receiving an alarm signal.

7. A current transformer characteristic rapid testing device according to claim 1, characterized in that: It also includes a step-down module, which is connected between the power supply module and the current transformer module, the feedback signal sampler, the excitation signal generator module, the microcontroller module and the display module. The step-down module reduces the power supply voltage to a working level that matches the microcontroller and other unit modules.

8. A current transformer characteristic rapid testing device according to claim 1, characterized in that: The microcontroller module will process the collected data and control the alarm module and display screen through the following steps: S1: The feedback signal amplitude obtained from the feedback signal sampler. The voltage value of the feedback signal is read using the ADC module and converted into a current value. The calculation formula is as follows: Where Current(A) is the calculated current value in amperes (A); ADC_Value is the digital value read from the ADC module, which usually ranges from 0 to 4095. ref It represents the reference voltage of the ADC module, in volts (V); β is the resolution of the ADC, δ represents the offset voltage, in volts (V); Sensitivity represents the sensitivity of the current sensor, in volts per ampere (V / A); S2: Set thresholds, including short-circuit thresholds and normal working thresholds, and compare the calculated current value with the thresholds: if the current value is greater than the short-circuit threshold, it is determined to be a short-circuit state; if the current value is within the normal working threshold range, it is determined to be a normal state; if the current value is close to zero, it is determined to be an open circuit state; S3: When a short circuit is detected, the microprocessor module will trigger the alarm module to sound and light an alarm; S4: Real-time display of current value and status information, including "normal", "short circuit" and "open circuit".

9. A computer-readable storage medium, characterized in that: The computer-readable storage medium includes a stored program, wherein when the program is executed, the device where the computer-readable storage medium is located is controlled to execute the control method of the microcontroller module according to claim 8.

10. A processor, characterized in that: The processor is used to run a program, wherein the control method of the microcontroller module according to claim 8 is executed when the program is run.

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