A rotor grounding resistance calculation method, system, storage medium and computing device

Abstract

This invention discloses a method, system, storage medium, and computing device for calculating rotor grounding resistance. The method includes: acquiring DC data corresponding to the number of sampling points between two switching operations of a rotor grounding protection switch; calculating the functional relationship between the DC data and the rotor grounding protection grounding resistance; filtering the first 10% of transient DC data acquired in real-time after the switch switching to reduce the impact of transient processes on calculation accuracy; and using the remaining DC data to calculate the grounding resistance of each sampling point, removing the largest and smallest 30% of data to filter sampling points with larger errors in grounding resistance calculation, thus minimizing the impact of low-value analog quantity errors on grounding resistance calculation; and performing a weighted average of the sampled data filtered after multiple switch switching operations to reduce the impact of sampling data errors on grounding resistance calculation, resulting in higher calculation accuracy and further improving the calculation accuracy of rotor grounding resistance under low-value analog quantity conditions.

Description

Technical Field

[0001] This invention relates to the technical field of power system relay protection, and in particular to a method, system, storage medium, and computing device for calculating rotor grounding resistance. Background Technology

[0002] The overall performance of domestically produced chips is currently somewhat behind that of overseas chips. However, domestic microprocessor protection manufacturers have adopted technologies such as redundancy, fault tolerance, and compensation, enabling most of the basic performance of microprocessor relay protection devices developed based on domestically produced chips to be comparable to those developed based on imported chips.

[0003] For rotor grounding protection, the mainstream rotor grounding protection schemes both domestically and internationally are ping-pong type rotor grounding protection and injection type rotor grounding protection. Although the implementation methods of ping-pong type and injection type rotor grounding protection differ, their principles are the same: both connect to the rotor winding through a switchable measurement circuit. The measurement circuit has two states depending on the switching switch. By solving the DC circuit under both states, the rotor grounding resistance and grounding location are calculated, and these calculated grounding resistance and grounding location are used as the operating parameters for the protection logic. The core criterion used in both types of protection schemes is grounding resistance, and the analog sample values ​​used for grounding resistance calculation are very small, even less than 1 mA.

[0004] For analog quantities acquired by conventional protective current transformers and voltage transformers, the acquisition accuracy can generally meet the requirements of existing relay protection standards after bias compensation and RMS compensation of the analog quantity channels. However, for low-value analog quantities used in rotor grounding protection, they are more susceptible to interference. Even after bias compensation and RMS compensation, these low-value analog quantities may still not meet the accuracy requirements for grounding resistance calculation. Summary of the Invention

[0005] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0006] In view of the aforementioned existing problems, the present invention is proposed.

[0007] Therefore, the present invention provides a method, system, storage medium, and computing device for calculating rotor grounding resistance to solve the problems mentioned in the background art.

[0008] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0009] In a first aspect, embodiments of the present invention provide a method for calculating rotor grounding resistance, including:

[0010] Obtain the DC data corresponding to the number of sampling points between two switching operations of the rotor grounding protection switch;

[0011] Calculate the functional relationship between the DC flow data and the rotor grounding protection grounding resistance;

[0012] The real-time DC flow data is preprocessed, and the rotor grounding resistance value is calculated based on the preprocessed DC flow data and the functional relationship.

[0013] As a preferred embodiment of the rotor grounding resistance calculation method of the present invention, the method includes: obtaining DC data corresponding to the number of sampling points between two switching of the rotor grounding protection switching switch, including:

[0014] The DC data refers to all DC data involved in the rotor grounding protection calculation.

[0015] As a preferred embodiment of the rotor grounding resistance calculation method of the present invention, the real-time DC data is preprocessed, including: a first preprocessing and a second preprocessing.

[0016] The first preprocessing includes processing the time between two switching operations of the rotor grounding protection switching switch. The DC flow filter corresponding to the sampling point is obtained to get the first sampling point. The DC flow rate corresponding to N sampling points;

[0017] Get The DC values ​​corresponding to each sampling point constitute a sample value array;

[0018] The sampled value arrays are represented as: x1s, x2s, ..., xMs, where the i-th element of the array is the i-th value. Data from each sampling point.

[0019] As a preferred embodiment of the rotor grounding resistance calculation method of the present invention, the second preprocessing includes:

[0020] According to the obtained For each sampling point, the grounding resistance is calculated by combining the DC data with the functional relationship between the rotor grounding protection grounding resistance.

[0021] The grounding resistances calculated from each sampling point are used to construct a grounding resistance array, which includes: The i-th element is the element of the i-th element. The grounding resistance is calculated from each sampling point.

[0022] As a preferred embodiment of the rotor grounding resistance calculation method of the present invention, it further includes:

[0023] Sort the grounding resistance array, and then sort the grounding resistance array in the first proportional stage. The indices in the array of elements constitute the first index array after the k-th switch is switched;

[0024] Similarly, let the index array obtained after the (k+1)th switch switching be the second index array;

[0025] Let the index array obtained after the (k+2)th switch switching be the third index array;

[0026] Let the index array obtained after the (k+p-1)th switch be the p-th index array, and a total of p index arrays are obtained.

[0027] As a preferred embodiment of the rotor grounding resistance calculation method of the present invention, the rotor grounding resistance value is calculated based on the preprocessed DC data and the functional relationship, including:

[0028] For M sample value arrays x1s, x2s, ..., xMs, let the average values ​​of the elements in the first index array be x11, x21, ..., xM1 respectively;

[0029] Let the average values ​​of the elements in the second subscript array be x12, x22, ..., xM2;

[0030] Let the average values ​​of the elements in the third subscript array be x13, x23, ..., xM3;

[0031] Let the average values ​​of the elements in the array with index p be x1p, x2p, ..., xMp.

[0032] As a preferred embodiment of the rotor grounding resistance calculation method of the present invention, wherein:

[0033] The rotor grounding resistance value is calculated and expressed as follows:

[0034]

[0035] ...

[0037]

[0038] Where k is the number of times the switch is switched.

[0039] Secondly, the present invention provides a rotor grounding resistance calculation system, comprising,

[0040] The data acquisition module is used to acquire the DC data corresponding to the number of sampling points between two switching of the rotor grounding protection switching switch;

[0041] The first calculation module is used to calculate the functional relationship between the DC flow data and the rotor grounding protection grounding resistance;

[0042] The second calculation module is used to preprocess the real-time DC data and calculate the rotor grounding resistance value based on the preprocessed DC data and the functional relationship.

[0043] Thirdly, the present invention provides a computing device, comprising:

[0044] Memory and processor;

[0045] The memory is used to store computer-executable instructions, and the processor is used to execute the computer-executable instructions, which, when executed by the processor, implement the steps of the rotor grounding resistance calculation method.

[0046] Fourthly, the present invention provides a computer-readable storage medium storing computer-executable instructions that, when executed by a processor, implement the steps of the rotor grounding resistance calculation method.

[0047] Compared with existing technologies, the beneficial effects of this invention are as follows: For DC data after switching, this invention first removes the first 10% of transient data to avoid the impact of transient processes on calculation accuracy. The remaining 90% of data is not directly used to calculate grounding resistance using an average value; instead, the grounding resistance is calculated for each point. Since the error caused by the interference of low-value analog quantities is directly reflected in the grounding resistance, compared to using an average value to calculate the grounding resistance, calculating the grounding resistance at each sampling point allows for filtering out sampling points with larger calculation errors by removing the largest and smallest 30% of data, thus minimizing the impact of low-value analog quantity errors on the grounding resistance calculation. By weighted averaging the sampled data filtered after multiple switching operations, the data used to calculate the grounding resistance is less affected by sampling data errors, resulting in higher calculation accuracy. This invention enables the rotor grounding resistance to achieve good calculation accuracy even under low-value analog quantity conditions. Attached Figure Description

[0048] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0049] Figure 1 This is a flowchart illustrating a method, system, storage medium, and computing device for calculating rotor grounding resistance according to an embodiment of the present invention. Detailed Implementation

[0050] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.

[0051] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0052] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0053] This invention is described in detail with reference to the schematic diagrams. When detailing the embodiments of this invention, for ease of explanation, the cross-sectional views illustrating the device structure may be partially enlarged, not adhering to the usual scale. Furthermore, the schematic diagrams are merely examples and should not be construed as limiting the scope of protection of this invention. In actual fabrication, the three-dimensional spatial dimensions of length, width, and depth should be included.

[0054] Furthermore, in the description of this invention, it should be noted that the terms "upper," "lower," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are used solely for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. In addition, the terms "first," "second," or "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0055] Unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" in this invention should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; similarly, they can refer to mechanical connections, electrical connections, or direct connections, or indirect connections through an intermediate medium, or internal connections between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0056] Example 1

[0057] Reference Figure 1 As one embodiment of the present invention, this embodiment provides a method for calculating rotor grounding resistance, including:

[0058] S1: Obtain the DC data corresponding to the number of sampling points between two switching of the rotor grounding protection switching switch;

[0059] Specifically, the DC data corresponding to the number of sampling points between two switching of the rotor grounding protection switch is obtained as all DC data involved in the rotor grounding protection calculation.

[0060] S2: Calculate the functional relationship between DC flow data and rotor grounding protection grounding resistance;

[0061] In this embodiment of the invention, the functional relationship between DC flow data and rotor grounding protection resistance can be calculated based on rotor grounding circuits from different manufacturers. Furthermore, the functional relationship can be trained using historical DC flow data and rotor grounding protection resistance values, etc. This invention is not specifically limited herein.

[0062] S3: Preprocess the real-time DC data, and calculate the rotor grounding resistance value based on the preprocessed DC data and the functional relationship.

[0063] Furthermore, the real-time direct flow data is preprocessed, including: first preprocessing and second preprocessing;

[0064] The first preprocessing includes processing the time between two switching operations of the rotor grounding protection switching switch. The DC flow filter corresponding to the sampling point is obtained to get the first sampling point. The DC flow rate corresponding to N sampling points;

[0065] Get The DC values ​​corresponding to each sampling point constitute a sample value array;

[0066] The sampled value arrays are represented as: x1s, x2s, ..., xMs, where the i-th element of the array is the i-th value. Data from each sampling point.

[0067] It should be noted that in this embodiment, DC sampling is performed between the two switching of the rotor grounding protection switching switch, and the number of sampling points is an integer multiple of 10, which is used to obtain accurate and effective data during preprocessing.

[0068] Furthermore, the second preprocessing includes:

[0069] According to the obtained For each sampling point, the grounding resistance is calculated by combining the DC data with the functional relationship between the rotor grounding protection grounding resistance.

[0070] The grounding resistances calculated from each sampling point are used to construct a grounding resistance array, which includes: The i-th element is the element of the i-th element. The grounding resistance is calculated from each sampling point.

[0071] It should be noted that there is generally a transient process after the switch is switched. In this embodiment, 10% of the DC data corresponding to the number of sampling points is removed to filter out this transient process. When the filtered DC data is less than 10%, it cannot be guaranteed that all transient data will be filtered out. When the filtered DC data is more than 10%, the effective data will be reduced and the calculation accuracy will be reduced.

[0072] Furthermore, this also includes:

[0073] Sort the grounding resistance array and select the first proportional stage of the grounding resistance array. The indices in the array of elements constitute the first index array after the k-th switch is switched;

[0074] Similarly, let the index array obtained after the (k+1)th switch switching be the second index array;

[0075] Let the index array obtained after the (k+2)th switch switching be the third index array;

[0076] Let the index array obtained after the (k+p-1)th switch be the p-th index array, and a total of p index arrays are obtained.

[0077] It should be noted that in this embodiment, the first proportional stage is the remaining part after sorting the grounding resistance array, removing the largest 30% and the smallest 30%.

[0078] Furthermore, based on the preprocessed DC data and combined with functional relationships, the rotor grounding resistance value is calculated, including:

[0079] For M sample value arrays x1s, x2s, ..., xMs, let the average values ​​of the elements in the first index array be x11, x21, ..., xM1 respectively;

[0080] Let the average values ​​of the elements in the second subscript array be x12, x22, ..., xM2;

[0081] Let the average values ​​of the elements in the third subscript array be x13, x23, ..., xM3.

[0082] Furthermore, the rotor grounding resistance value is calculated as follows:

[0083]

[0084] ...

[0086]

[0087] Where k is the number of times the switch is switched.

[0088] The above is a schematic scheme of a rotor grounding resistance calculation method according to this embodiment. It should be noted that the technical solution of this rotor grounding resistance calculation system and the technical solution of the rotor grounding resistance calculation method described above belong to the same concept. For details not described in detail in the technical solution of the rotor grounding resistance calculation system in this embodiment, please refer to the description of the technical solution of the rotor grounding resistance calculation method described above.

[0089] This embodiment provides a rotor grounding resistance calculation system, comprising:

[0090] The data acquisition module is used to acquire the DC data corresponding to the number of sampling points between two switching of the rotor grounding protection switching switch;

[0091] The first calculation module is used to calculate the functional relationship between DC flow data and rotor grounding protection grounding resistance;

[0092] The second calculation module is used to preprocess the real-time DC data and calculate the rotor grounding resistance value based on the preprocessed DC data and the functional relationship.

[0093] This embodiment also provides a computing device applicable to rotor grounding resistance calculation methods, including:

[0094] The system includes a memory and a processor. The memory stores computer-executable instructions, and the processor executes these instructions to implement the rotor grounding resistance calculation method proposed in the above embodiments.

[0095] This embodiment also provides a storage medium storing a computer program that, when executed by a processor, implements the rotor grounding resistance calculation method proposed in the above embodiments.

[0096] The storage medium proposed in this embodiment and the method for calculating rotor grounding resistance proposed in the above embodiments belong to the same inventive concept. Technical details not described in detail in this embodiment can be found in the above embodiments, and this embodiment has the same beneficial effects as the above embodiments.

[0097] Based on the above description of the implementation methods, those skilled in the art can clearly understand that the present invention can be implemented using software and necessary general-purpose hardware, and of course, it can also be implemented using hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as a computer floppy disk, read-only memory (ROM), random access memory (RAM), flash memory, hard disk, or optical disk, etc., including several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods of the various embodiments of the present invention.

[0098] Example 2

[0099] Reference Figure 1 This is one embodiment of the present invention. This embodiment differs from the first embodiment in that it provides a specific example of a method for calculating rotor grounding resistance, in order to verify the beneficial effects of our invention.

[0100] Assume there are 6 DC quantities involved in the rotor grounding protection calculation, and the number of sampling points between two switching of the rotor grounding protection switch is based on one per second, with a total of 100 sampling points.

[0101] The functional relationship between DC flow data and rotor grounding protection grounding resistance is expressed as:

[0102] Rg=f(x1,x2,x3,x4,x5,x6,)

[0103] The sampled value arrays composed of 6 DC inputs are: x1s, x2s, x3s, x4s, x5s, x6s;

[0104] After removing the first 10% of transient data, the grounding resistance is calculated for each of the remaining 90% of the data.

[0105] The grounding resistance array for sampling points 11 to 100 is represented as follows:

[0106] Rg 11 =f 11 (x1,x2,x3,x4,x5,x6,)

[0107] Rg 12 =f 11 (x1,x2,x3,x4,x5,x6,)

[0108] ...

[0109] Rg 100 =f 100 (x1,x2,x3,x4,x5,x6,)

[0110] Sort the above 90 grounding resistance arrays, filter out the grounding resistance arrays in order 1 to 30 and 61 to 90, and form the subscript array Rsub1 with the subscripts in the arrays in order 31 to 60; similarly, combined with the above operations, record the subscript array obtained after the last switching switch as Rsub2; record the subscript array obtained after the last switching switch as Rsub3.

[0111] Let the average values ​​of the elements with index Rsub1 be x11, x21, x31, x41, x51, x61; let the average values ​​of the elements with index Rsub2 be x12, x22, x32, x42, x52, x62; and let the average values ​​of the elements with index Rsub3 be x13, x23, x33, x43, x53, x63.

[0112] The rotor grounding resistance value is calculated and expressed as follows:

[0113] Rgf=f[(x11×3+x12×2+x13) / 6,

[0114] (x21×3+x22×2+x23) / 6,

[0115] (x31×3+x32×2+x33) / 6,

[0116] (x41×3+x42×2+x43) / 6,

[0117] (x51×3+x52×2+x53) / 6,

[0118] (x61×3+x62×2+x63) / 6]

[0119] This invention, for DC data after a switching switch changeover, first removes the first 10% of transient data to avoid the impact of transient processes on calculation accuracy. For the remaining 90% of data, instead of directly using an average value to calculate grounding resistance, the grounding resistance is calculated at each point. Since errors caused by interference from low-value analog quantities are directly reflected in the grounding resistance, calculating the grounding resistance at each point, compared to using an average value, allows for the filtering out of sampling points that significantly affect the grounding resistance. By removing the largest and smallest 30% of the calculated grounding resistance data from each sampling point, sampling points that cause significant errors in the grounding resistance calculation are filtered out, minimizing the impact of low-value analog quantity errors on the grounding resistance calculation. By weighted averaging the sampled data selected after the current, previous, and previous-previous switch changes, the data used to calculate the grounding resistance is less affected by sampling data errors, resulting in higher calculation accuracy. These various measures of this invention enable the rotor grounding resistance to achieve good calculation accuracy even under low-value analog quantity conditions.

[0120] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for calculating rotor grounding resistance, characterized in that, include: Obtain the DC data corresponding to the number of sampling points between two switching operations of the rotor grounding protection switch; Calculate the functional relationship between the DC flow data and the rotor grounding protection grounding resistance; The real-time DC data is preprocessed, and the rotor grounding resistance value is calculated based on the preprocessed DC data and the functional relationship. The real-time direct flow data is preprocessed, including: first preprocessing and second preprocessing; The first preprocessing includes processing the time between two switching operations of the rotor grounding protection switching switch. The DC flow filter corresponding to the sampling point is obtained to get the first sampling point. DC quantities corresponding to +1 to N sampling points; Get The DC values ​​corresponding to each sampling point constitute a sample value array; The sampled value arrays are represented as follows: The array number The element is the first +i sampling points of data; The second preprocessing includes: According to the obtained For each sampling point, the grounding resistance is calculated by combining the DC data with the functional relationship between the rotor grounding protection grounding resistance. The grounding resistances calculated from each sampling point are used to construct a grounding resistance array, which includes: The element, the first The element is the first The grounding resistance is calculated from +i sampling points; Sort the grounding resistance array, and then sort the grounding resistance array in the first proportional stage. The indices of the array of elements constitute the first element. The first index array after the next switch is switched; Similarly, let the first... The index array obtained after the switch is switched is the second index array; Record No. The subscript array obtained after the switch is switched is the third subscript array; Record No. The index array obtained after switching the switch -1 times is the p-th index array, and a total of p index arrays are obtained; Based on the preprocessed DC data and the aforementioned functional relationship, the rotor grounding resistance value is calculated. include: For M sample value arrays Let the flatness of the elements of the first index array be... The means are respectively Let the average values ​​of the elements in the second subscript array be respectively ; Let the average values ​​of the elements in the third subscript array be respectively ; Let the average values ​​of the elements of the array with index p be respectively ; The rotor grounding resistance value is calculated and expressed as follows: in, This represents the number of times the switch has been toggled.

2. The rotor grounding resistance calculation method as described in claim 1, characterized in that, Obtain the DC data corresponding to the number of sampling points between two switching operations of the rotor grounding protection switch, including: The DC data refers to all DC data involved in the rotor grounding protection calculation.

3. A rotor grounding resistance calculation system, characterized in that, The method of claim 1 is used, comprising: The data acquisition module is used to acquire DC data corresponding to the number of sampling points between two switching of the rotor grounding protection switching switch; The first calculation module is used to calculate the functional relationship between the DC flow data and the rotor grounding protection grounding resistance; The second calculation module is used to preprocess the real-time DC data and calculate the rotor grounding resistance value based on the preprocessed DC data and the functional relationship.

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

5. A computer-readable storage medium storing computer-executable instructions that, when executed by a processor, implement the steps of the rotor grounding resistance calculation method according to any one of claims 1 to 2.

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