Current transformer output current compensation method, device, equipment and storage medium

Abstract

The application relates to a current transformer output current compensation method, device, equipment and storage medium, which is applied to the field of current transformers, and the method comprises the following steps: acquiring a starting point of a linear section of a current transformer output current; selecting a fixed number of sample current data in a plurality of output current data of the current transformer with the starting point as an end point; performing effective value calculation according to the sample current data to obtain the root mean square corresponding to the sample current data; and performing data compensation on the output current of the current transformer according to the root mean square. The application has the technical effect that the problems of the measurement accuracy of plastic shell electronic products and the reliability of large current protection are effectively solved.

Description

Technical Field

[0001] The present application relates to the technical field of current transformers, and in particular to a current transformer output current compensation method, device, equipment and storage medium. Background Art

[0002] Molded case circuit breakers have a wide range of applications, with electronic products accounting for an increasing proportion. Overload, short-circuit, and other protection features of electronic molded case circuit breakers require real-time sampling of the main circuit current. However, due to the size and installation space limitations of molded case circuit breakers, even current transformers made from materials with good magnetic conductivity find it difficult to achieve the linear, unsaturated range requirement of (0.2-14) In. Therefore, manufacturers generally adopt current transformers that ensure that the main circuit current is linear at low magnifications and saturated at high magnifications. For protection against high currents such as overcurrent and short circuits, current transformers use a microprocessor to perform effective value or peak sampling and compensation as a workaround. However, the consistency of the current transformer's materials and production process significantly impacts the accuracy of the circuit breaker's high-current protection, such as overcurrent and short circuit protection.

[0003] When using a microprocessor to sample the effective value or peak value of the current transformer's output current and perform compensation, the root mean square (RMS) of the current transformer's secondary current is typically calculated and then multiplied by the compensation coefficient in sections. This approach is used by most manufacturers of molded case circuit breakers. Its advantages include segmented compensation, the ability to average the values ​​after mass production, and the ability to calibrate at designated key protection points, enabling successive corrections and ultimately achieving mass compensation.

[0004] In the process of realizing the present application, the inventors discovered that there are at least the following problems in this technology: when the production process of the current transformer changes, resulting in a change in the saturation point, the batch accuracy is likely to decrease. Summary of the Invention

[0005] In order to effectively solve the measurement accuracy and high current protection reliability problems of plastic shell electronic products, the present application provides a current transformer output current compensation method, device, equipment and storage medium.

[0006] In a first aspect, the present application provides a current transformer output current compensation method, which adopts the following technical solution: the method comprises: obtaining a starting point of a linear section of the current transformer output current;

[0007] Taking the starting point as an endpoint, selecting a fixed number of sample current data from a plurality of output current data of the current transformer;

[0008] Performing effective value calculation based on the sample current data to obtain a root mean square (RMS) value corresponding to the sample current data;

[0009] Data compensation is performed on the output current of the current transformer according to the root mean square.

[0010] Through the above technical solution, the current transformer output current compensation system uses the starting point of the linear segment of the current transformer's output current as the endpoint, extracts a fixed number of sample current data from the output current data after the starting point, calculates the effective value (RMS) corresponding to the sample current data, and then compensates the current transformer's output current based on the calculated RMS. This improves the compensation effect on the current transformer's output current.

[0011] In a specific implementation scheme, obtaining the starting point of the linear section of the current transformer output current specifically includes:

[0012] Collecting samples from a plurality of output current data of the current transformer according to a preset sampling frequency and sampling period to obtain a plurality of continuous current sampling values;

[0013] Obtaining several standard sampling values;

[0014] Calculate the sampling operation value according to the preset calculation formula, continuous current sampling value and standard sampling value;

[0015] The minimum sampling operation value among the plurality of sampling operation values ​​is used as the starting point of the linear segment.

[0016] Through the above technical solution, the current transformer output current compensation system obtains the starting point of the linear section of the current transformer output current by first sampling the output current of the current transformer to obtain a number of continuous current sampling values. Then, the standard sampling values ​​preset and stored in the current transformer output current compensation system are retrieved. The standard sampling values ​​and the continuous current sampling values ​​are sequentially substituted into a preset calculation formula to obtain the corresponding sampling operation values. The sampling operation value with the smallest value among the several sampling operation values ​​is set as the starting point of the linear section. This enables the current transformer output current compensation system to more accurately find the starting point of the linear section of the current transformer output current.

[0017] In a specific embodiment, the obtaining of a plurality of standard sampling values ​​specifically includes:

[0018] Sampling is performed at a preset sampling frequency in a non-distorted section of the output current of the current transformer to obtain a plurality of sampling points;

[0019] Extracting a fixed number of primary sampling points from the sampling points according to a preset sampling range;

[0020] The current value corresponding to the primary sampling point is multiplied by a preset magnification factor to obtain a corresponding standard sampling value.

[0021] Through the above technical solution, the current transformer output current compensation system obtains a number of sampling points by sampling in the non-distortion section of the current transformer, and screens the sampling points according to a preset sampling range, and extracts a fixed number of primary sampling points from the screened sampling points. Then, the values ​​of the primary sampling points are amplified according to a preset amplification factor to obtain corresponding standard sampling values. The amplification processing of the primary sampling point values ​​helps to improve the operation speed of the current transformer output current compensation system and enhance the processing efficiency of the current transformer output current compensation system.

[0022] In a specific implementation scheme, performing data compensation on the output current of the current transformer according to the root mean square comprises:

[0023] Calculate the effective value of the current transformer output current in a single cycle;

[0024] Calculating a ratio between a root mean square value corresponding to the sample current data and the effective value;

[0025] The current transformer output current is multiplied by the ratio.

[0026] Through the above technical solution, the current transformer output current compensation system uses the linear section of the current transformer output current to calculate the root mean square to compensate the output current, thereby improving the overall compensation effect.

[0027] In a specific implementation scheme, the calculation formula is specifically:

[0028]

[0029] S i is the continuous current sampling value; K i is the standard sampling value; M j is the sampling operation value.

[0030] Through the above technical solution, the current transformer output current compensation system can use the calculation formula to calculate the required sampling operation value more accurately and quickly, providing data support for the subsequent current transformer output current compensation system to find the starting point of the linear section of the current transformer output current.

[0031] In a second aspect, the present application provides a current transformer output current compensation device, which adopts the following technical solution: the device includes:

[0032] A linear section starting point acquisition module is used to obtain the starting point of the linear section of the current transformer output current;

[0033] A sample current data sampling module is used to select a fixed number of sample current data from a plurality of output current data of the current transformer with the starting point as an end point;

[0034] a sample current data effective value calculation module, configured to perform effective value calculation based on the sample current data to obtain a root mean square (RMS) value corresponding to the sample current data;

[0035] The output current compensation module is used to perform data compensation on the output current of the current transformer according to the root mean square.

[0036] In a third aspect, the present application provides a computer device that adopts the following technical solution: it includes a memory and a processor, and the memory stores a computer program that can be loaded and executed by the processor, such as any of the current transformer output current compensation methods described above.

[0037] In a fourth aspect, the present application provides a computer-readable storage medium, which adopts the following technical solution: storing a computer program that can be loaded by a processor and execute any of the above-mentioned current transformer output current compensation methods.

[0038] In summary, this application includes at least one of the following beneficial technical effects:

[0039] 1. The current transformer output current compensation system uses the starting point of the linear segment of the current transformer's output current as the endpoint. It extracts a fixed number of sample current data from the output current data after the starting point, calculates the effective value (RMS) corresponding to the sample current data, and then compensates the current transformer's output current based on the calculated RMS. This improves the compensation effect on the current transformer's output current.

[0040] 2. The current transformer output current compensation system obtains the starting point of the linear section of the current transformer output current by first sampling the current transformer output current to obtain a number of continuous current sampling values. The system then retrieves the standard sampling values ​​stored in the current transformer output current compensation system, substitutes the standard sampling values ​​and the continuous current sampling values ​​into a preset calculation formula, and calculates the corresponding sampling operation values. The sampling operation value with the smallest value among the several sampling operation values ​​is set as the starting point of the linear section. This ensures that the current transformer output current compensation system can more accurately find the starting point of the linear section of the current transformer output current. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 This is a flow chart of a current transformer output current compensation method in an embodiment of the present application.

[0042] Figure 2It is a table diagram used to display the numerical values ​​of standard sampling values ​​in the embodiments of this application.

[0043] Figure 3 It is a structural block diagram of the current transformer output current compensation device in an embodiment of the present application.

[0044] Reference numerals: 301, linear section starting point acquisition module; 302, sample current data sampling module; 303, sample current data effective value calculation module; 304, output current compensation module. DETAILED DESCRIPTION

[0045] The following is combined with Figure 1-3 This application is described in further detail.

[0046] The present application discloses a method for compensating the output current of a current transformer. This method is applied to a current transformer output current compensation system. The corresponding code for this method is stored in the control center of the current transformer output current compensation system. After comparing and analyzing test data of various types of current transformers for molded case circuit breakers and different saturation current multiples, the staff found that when the output current of the circuit transformer is in a saturated state, the current transformer is affected by hysteresis. After the output current of the current transformer passes through zero, there is always a section of the waveform corresponding to the output current in an unsaturated state. In other words, the output current of the current transformer has a waveform section with a near-linear secondary output.

[0047] like Figure 1 As shown, the method includes the following steps:

[0048] S10, obtaining the starting point of the linear section of the current output by the current transformer.

[0049] Specifically, the output current of the current transformer has a waveform section where the secondary output is close to linear. The current transformer output current compensation system uses the effective value corresponding to the sampling point of this linear section to compensate the output current of the current transformer. Therefore, the current transformer output current compensation system first needs to obtain the starting point of the linear section in the current transformer output current. Different current transformers have different phases in the corresponding linear regions due to differences in manufacturing processes and the number of coil hoops. The steps for the current transformer output current compensation system to obtain the starting point of the linear section of the current transformer output current can be specifically performed as follows:

[0050] The current transformer output current compensation system first samples a plurality of output current data of the current transformer according to a preset sampling frequency and sampling period to obtain a plurality of continuous current sample values; in this embodiment, the sampling method is AD sampling, then the current transformer output current compensation system calls a plurality of standard sample values preset in the current transformer output current compensation system, and then inputs the continuous current sample values obtained by sampling and the called standard sample values into a preset calculation formula to obtain a plurality of sample operation values, next, the current transformer output current compensation system selects the sample operation value with the smallest corresponding value from the sample operation values according to the numerical value of the sample operation value as the starting point of the linear section of the current transformer output current.

[0051] S20, selecting a fixed number of sample current data from the plurality of output current data of the current transformer with the starting point as the end point.

[0052] Specifically, the current transformer output current compensation system extracts a fixed number of current data values from the current transformer corresponding to the plurality of output current data after the end point as sample current data with the starting point as the end point, and it should be noted that the number of sample current data needs to be set according to the current transformer, and in this embodiment, the number of sample current data is 10.

[0053] S30, calculating the effective value according to the sample current data.

[0054] Specifically, the effective value of the sample current data is the root mean square corresponding thereto, the current transformer output current compensation system first squares all the sample current data and then sums them up, then calculates the corresponding mean value, and finally squares the calculated mean value.

[0055] S40, compensating the output current of the current transformer according to the root mean square.

[0056] Specifically, after the current transformer output current compensation system calculates the effective value corresponding to the sample current data, it calculates the effective value of the current transformer output current in a period, and then calculates the ratio between the effective value corresponding to the sample current data and the effective value of the current transformer output current in a period, and takes the ratio as a compensation coefficient to compensate the current transformer output current. The current transformer output current compensation system uses the linear section of the current transformer output current to calculate the compensation coefficient using the sample values of the linear section, which helps to improve the compensation effect of the current transformer output current compensation system on the current transformer output current.

[0057] In one embodiment, in order to improve the accuracy of compensating the current transformer output current, a plurality of standard sample values are obtained, which can be implemented as follows:

[0058] like Figure 2 As shown, the current transformer output current compensation system samples the non-distorted segment of the current transformer output current at a preset sampling frequency to obtain a number of sampling points. A fixed number of sampling points are then extracted from the sampled points according to a preset sampling range, which are recorded as primary sampling points. To facilitate calculations by the current transformer output current compensation system, the current transformer output current compensation system multiplies the current values ​​corresponding to the primary sampling points by a preset amplification factor to obtain the corresponding standard sampling values. In this embodiment, the amplification factor is 1000 times, and the preset sampling range in the current transformer output current compensation system is 36.56250° to 59.06250°. The current transformer output current compensation system samples within the range of 36.56250° to 59.06250° at a sampling frequency of 128 points every 20 ms. It is worth mentioning that when sampling, the current transformer output current compensation system should select sampling points in the non-distortion section (i.e., the sinusoidal function interval after the current transformer hysteresis ends and the transformer is not saturated) based on the saturation characteristics of the current transformer and the maximum current multiple during operation. This is determined by the hysteresis characteristics after the current transformer is saturated and the saturation speed (saturated current multiple). The current transformer output current compensation system can sample multiple values ​​when extracting primary sampling points. The more values, the more accurate the calculation. In this embodiment, the fixed number of primary sampling points extracted is 8. The current transformer output current compensation system helps to improve the compensation effect of the current transformer output current compensation system on the current transformer output current by sampling in the non-distortion section of the current transformer.

[0059] In one embodiment, the calculation formula is specifically shown as follows:

[0060]

[0061] Among them, S i is the continuous current sampling value; K i is the standard sampling value; M j is the sampled calculation value. The current transformer output current compensation system needs to be able to accurately find the starting point of this relatively linear waveform segment in the current transformer output current every time, and the current magnitude cannot affect the phase of the linear segment, and the sampling window phase shift cannot affect the phase of the linear segment. This application uses the principle of discrete Fourier transform to find the starting point of this linear segment. Under the condition of a frequency of 128 points sampled in 20ms, the above formula is deduced based on Fourier transform.

[0062] Figure 1 FIG. 1 is a flow chart of a current transformer output current compensation method in one embodiment. It should be understood that although Figure 1The steps in the flowchart are shown in sequence as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows; unless otherwise specified herein, there is no strict order restriction on the execution of these steps, and these steps may be executed in other orders; and Figure 1 At least part of the steps may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily executed at the same time, but can be executed at different times. The execution order of these sub-steps or stages is not necessarily sequential, but can be executed in turn or alternately with other steps or at least part of the sub-steps or stages of other steps.

[0063] Based on the above method, an embodiment of the present application also discloses a current transformer output current compensation device.

[0064] like Figure 3 As shown, the device includes the following modules:

[0065] A linear section starting point acquisition module 301 is used to acquire the starting point of the linear section of the current transformer output current;

[0066] The sample current data sampling module 302 is used to select a fixed number of sample current data from a plurality of output current data of the current transformer with the starting point as the endpoint;

[0067] The sample current data effective value calculation module 303 is used to perform effective value calculation based on the sample current data to obtain the root mean square (RMS) corresponding to the sample current data;

[0068] The output current compensation module 304 is configured to perform data compensation on the output current of the current transformer according to the root mean square.

[0069] In one embodiment, the linear section starting point acquisition module 301 is further configured to collect samples from a plurality of output current data of the current transformer according to a preset sampling frequency and sampling period to obtain a plurality of continuous current sampling values;

[0070] Obtaining several standard sampling values;

[0071] Calculate the sampling operation value according to the preset calculation formula, continuous current sampling value and standard sampling value;

[0072] The minimum sampling operation value among several sampling operation values ​​is used as the starting point of the linear interval.

[0073] In one embodiment, the sample current data sampling module 302 is further configured to sample the non-distorted section of the current transformer output current at a preset sampling frequency to obtain a plurality of sampling points;

[0074] A fixed number of primary sampling points are extracted from the sampling points according to a preset sampling range;

[0075] The current value corresponding to the primary sampling point is multiplied by the preset magnification factor to obtain the corresponding standard sampling value.

[0076] In one embodiment, the output current compensation module 304 is further configured to calculate the effective value of the output current of the current transformer in a single cycle;

[0077] Calculate the ratio between the root mean square value and the effective value corresponding to the sample current data;

[0078] Multiply the current transformer output current by the ratio.

[0079] In one embodiment, the linear segment starting point acquisition module 301 is further used to calculate the formula, specifically:

[0080]

[0081] S i is the continuous current sampling value; K i is the standard sampling value; M j is the sampling operation value.

[0082] The embodiment of the present application also discloses a computer device.

[0083] Specifically, the computer device includes a memory and a processor, and the memory stores a computer program that can be loaded by the processor and execute the above-mentioned current transformer output current compensation method.

[0084] The embodiment of the present application also discloses a computer-readable storage medium.

[0085] Specifically, the computer-readable storage medium stores a computer program that can be loaded by a processor and execute the above-mentioned current transformer output current compensation method. The computer-readable storage medium includes, for example: a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, and other media that can store program codes.

[0086] This specific embodiment is merely an explanation of the present invention and is not intended to limit the present invention. After reading this specification, those skilled in the art may make non-creative modifications to this embodiment as needed. However, as long as such modifications are within the scope of the claims of the present invention, they are protected by patent law.

Claims

1. A current transformer output current compensation method, characterized in that: The method comprises: Obtain the starting point of the linear section of the current transformer output current; Taking the starting point as an endpoint, selecting a fixed number of sample current data from a plurality of output current data of the current transformer; Performing effective value calculation based on the sample current data to obtain a root mean square (RMS) value corresponding to the sample current data; Performing data compensation on the output current of the current transformer according to the root mean square; The step of obtaining the starting point of the linear section of the current transformer output current specifically includes: Collecting samples from a plurality of output current data of the current transformer according to a preset sampling frequency and sampling period to obtain a plurality of continuous current sampling values; Obtaining several standard sampling values; Calculate the sampling operation value according to the preset calculation formula, continuous current sampling value and standard sampling value; The minimum sampling operation value among the plurality of sampling operation values ​​is used as the starting point of the linear segment; The calculation formula is specifically: S i is the continuous current sampling value; K i is the standard sampling value; M j is the sampling operation value; j represents the jth sampling point.

2. The method according to claim 1, characterized in that The obtaining of a number of standard sampling values ​​specifically includes: Sampling is performed at a preset sampling frequency in a non-distorted section of the output current of the current transformer to obtain a plurality of sampling points; Extracting a fixed number of primary sampling points from the sampling points according to a preset sampling range; The current value corresponding to the primary sampling point is multiplied by a preset magnification factor to obtain a corresponding standard sampling value.

3. The method according to claim 1, characterized in that The performing data compensation on the output current of the current transformer according to the root mean square comprises: Calculate the effective value of the current transformer output current in a single cycle; Calculating a ratio between a root mean square value corresponding to the sample current data and the effective value; The current transformer output current is multiplied by the ratio.

4. A current transformer output current compensation device, the device being based on any one of the methods of claims 1 to 3, characterized in that: The device comprises: A linear section starting point acquisition module (301) is used to acquire the starting point of the linear section of the current transformer output current; A sample current data sampling module (302) is used to select a fixed number of sample current data from a plurality of output current data of the current transformer with the starting point as an end point; A sample current data effective value calculation module (303) is used to perform effective value calculation based on the sample current data to obtain a root mean square value corresponding to the sample current data; An output current compensation module (304) is used to perform data compensation on the output current of the current transformer according to the root mean square.

5. A computer device, characterized in that: The method comprises a memory and a processor, wherein the memory stores a computer program that can be loaded by the processor and executes the method according to any one of claims 1 to 3.

6. A computer-readable storage medium, characterized in that A computer program is stored which can be loaded by a processor and execute the method according to any one of claims 1 to 3.

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