Method, device and storage medium for determining residual magnetic flux of transformer

Abstract

The present invention discloses a method, device and storage medium for determining the residual magnetic flux of a transformer. The method comprises: obtaining a current signal generated by at least one transformer in a power grid at at least one node at the moment of power failure; determining a target current peak value from the current peak value corresponding to the current signal, wherein the target current peak value is used to represent each current peak value between adjacent cycles of the node at the moment of power failure; performing linear fitting on the target current peak value based on a fitting template to obtain the fitting goodness of the original current signal and the fitting curve of the attenuation characteristic corresponding to the current signal; in response to the fitting goodness exceeding the fitting goodness threshold, determining the residual magnetic flux of the transformer under the original current signal based on a preset database corresponding to the type of the transformer, wherein the preset database is used to store the mapping relationship between the original current signal and the residual magnetic flux. The present invention solves the technical problem of low efficiency in estimating the residual magnetic flux of the transformer.

Description

Technical Field

[0001] The present invention relates to the field of electric power, and in particular to a method, a device and a storage medium for determining the residual magnetic flux of a transformer. Background Art

[0002] At present, in the power system, due to the residual magnetism of the iron core in the transformer, a large excitation surge current will be generated on one side of the transformer when the transformer is closed. Therefore, the estimation of residual magnetism is particularly important. However, the current detection methods for the residual magnetism of the iron core in the transformer are generally empirical methods, pre-magnetization methods, etc. In the empirical method, the transformer is analyzed after the switch is opened, and then a relatively wide residual magnetism range is judged. This method cannot accurately meet the estimation requirements of the residual magnetism range. In the pre-magnetization method, the residual magnetism of the iron core is measured by DC voltage excitation. Although this method has measured the residual magnetism value, it has changed the residual magnetism inside the iron core. At the same time, a large current is required to generate a saturation flux. It is not suitable for actual engineering applications, resulting in a technical problem of low efficiency in estimating the residual flux of the transformer.

[0003] With respect to the technical problem of low efficiency in estimating the residual magnetic flux of the above-mentioned transformer, no effective solution has been proposed so far. Summary of the invention

[0004] The embodiments of the present invention provide a method, a device and a storage medium for determining the residual magnetic flux of a transformer, so as to at least solve the technical problem of low efficiency in estimating the residual magnetic flux of the transformer.

[0005] According to one aspect of an embodiment of the present invention, a method for determining the residual magnetic flux of a transformer is provided. The method includes: obtaining a current signal generated by at least one transformer in a power grid at at least one node at the moment of power failure; determining a target current peak value from the current peak value corresponding to the current signal, wherein the target current peak value is used to represent each current peak value between adjacent cycles of the node at the moment of power failure; performing linear fitting on the target current peak value based on a fitting template to obtain the fitting goodness of fit of the original current signal and the fitting curve of the attenuation characteristic corresponding to the current signal, wherein the fitting template is used to represent the rule for performing linear fitting on the target current peak value, and the original current signal is used to represent the current signal generated by the transformer at the node before the moment of power failure; in response to the fitting goodness exceeding the fitting goodness threshold, determining the residual magnetic flux of the transformer under the original current signal based on a preset database corresponding to the type of the transformer, wherein the preset database is used to store the mapping relationship between the original current signal and the residual magnetic flux.

[0006] Optionally, based on the fitting template, a linear fit is performed on the target current peak to obtain the goodness of fit of the original current signal and the fitting curve of the attenuation characteristic corresponding to the current signal, including: based on the target current peak, determining the attenuation coefficient of the current signal between adjacent cycles; determining the average value of the attenuation coefficient; based on the fitting template, performing a linear fit on the average value to obtain the goodness of fit.

[0007] Optionally, based on the fitting template, a linear fit is performed on the average value to obtain a goodness of fit, including: in response to the fitting template being a first fitting template, the average value is input into the first fitting template for linear fitting to obtain a first goodness of fit, wherein the first goodness of fit is used to represent the goodness of fit of the fitting curve of the original current signal and the attenuation characteristic under the first fitting template; in response to the fitting template being a second fitting template, the average value is input into the second fitting template for linear fitting to obtain a second goodness of fit, wherein the second goodness of fit is used to represent the goodness of fit of the fitting curve of the original current signal and the attenuation characteristic under the second fitting template, and the goodness of fit includes the first goodness of fit and the second goodness of fit.

[0008] Optionally, in response to the fitting template being the first fitting template, the average value is input into the first fitting template for linear fitting to obtain a first goodness of fit, including: in response to the fitting template being the first fitting template, the average value is input into the fitting model in the first fitting template for linear fitting to obtain an original current signal; and an error calculation is performed on the original current signal to obtain a first goodness of fit.

[0009] Optionally, in response to the fitting template being the second fitting template, the average value is input into the second fitting template for linear fitting to obtain a second goodness of fit, including: in response to the fitting template being the second fitting template, the average value is input into the fitting model in the second fitting template for linear fitting to obtain the original current signal; and error calculation is performed on the original current signal to obtain the second goodness of fit.

[0010] Optionally, in response to the goodness of fit exceeding a goodness of fit threshold, based on a preset database corresponding to the type of transformer, the residual magnetic flux of the transformer under the original current signal is determined, including: in response to the goodness of fit of the fitting curve of the original current signal and the attenuation characteristic under a first fitting template exceeding the goodness of fit threshold, or, in response to the goodness of fit of the fitting curve of the original current signal and the attenuation characteristic under a second fitting template exceeding the goodness of fit threshold, determining the original current value corresponding to the original current signal; in the preset database, determining the residual magnetic flux of the transformer under the original current value.

[0011] Optionally, the method also includes: in response to the goodness of fit of the fitting curve of the original current signal and the attenuation characteristic under the first fitting template not exceeding the goodness of fit threshold, determining the attenuation coefficient of the current signal between adjacent cycles; determining the average value of the attenuation coefficient; inputting the average value into the second fitting template for linear fitting to obtain a second goodness of fit, wherein the second goodness of fit is used to represent the goodness of fit of the fitting curve of the original current signal and the attenuation characteristic under the second fitting template; in response to the goodness of fit of the fitting curve of the original current signal and the attenuation characteristic under the second fitting template not exceeding the goodness of fit threshold, determining the attenuation coefficient of the current signal between adjacent cycles; determining the average value of the attenuation coefficient; inputting the average value into the first fitting template for linear fitting to obtain a first goodness of fit, wherein the first goodness of fit is used to represent the goodness of fit of the fitting curve of the original current signal and the attenuation characteristic under the first fitting template.

[0012] According to one aspect of an embodiment of the present invention, a device for determining the residual magnetic flux of a transformer is provided. The device may include: an acquisition unit, for acquiring a current signal generated by at least one transformer in a power grid at at least one node at the moment of power failure; a determination unit, for determining a target current peak value from the current peak value corresponding to the current signal, wherein the target current peak value is used to represent each current peak value between adjacent cycles of the node at the moment of power failure; a fitting unit, for performing linear fitting on the target current peak value based on a fitting template to obtain the fitting goodness of fit of the original current signal and the fitting curve of the attenuation characteristic corresponding to the current signal, wherein the fitting template is used to represent the rule for performing linear fitting on the target current peak value, and the original current signal is used to represent the current signal generated by the transformer at the node before the moment of power failure; a response unit, for determining the residual magnetic flux of the transformer under the original current signal based on a preset database corresponding to the type of the transformer in response to the fitting goodness exceeding the fitting goodness threshold, wherein the preset database is used to store the mapping relationship between the original current signal and the residual magnetic flux.

[0013] According to another aspect of an embodiment of the present invention, a computer-readable storage medium is provided, wherein 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 method for determining the residual magnetic flux of the transformer of the embodiment of the present invention.

[0014] According to another aspect of an embodiment of the present invention, a processor is provided, which is used to run a program, wherein when the program is run by the processor, the method for determining the residual magnetic flux of the transformer according to an embodiment of the present invention is executed.

[0015] According to another aspect of an embodiment of the present invention, a computer program product is further provided. The computer program product includes a computer program. When the computer program is executed by a processor, the method for determining the residual magnetic flux of the transformer according to an embodiment of the present invention is implemented.

[0016] In an embodiment of the present invention, a current signal generated by at least one transformer in a power grid at at least one node at the moment of power failure is obtained, and then a target current peak value is determined from the current peak value corresponding to the generated current signal, that is, each current peak value between adjacent cycles of the node at the moment of power failure is determined, and then according to the rule of linear fitting of the target current peak value, by linear fitting of the target current peak value, the goodness of fit of the original current signal and the fitting curve of the attenuation characteristic corresponding to the current signal can be obtained, and by judging the relationship between the goodness of fit and the goodness of fit threshold, if it is judged that the obtained goodness of fit exceeds the goodness of fit threshold, the residual magnetic flux of the transformer under the original current signal is determined according to a preset database corresponding to the type of transformer, thereby achieving the purpose of determining a more detailed range of the residual magnetic flux, solving the technical problem of low efficiency in estimating the residual magnetic flux of the transformer, and achieving the technical effect of improving the efficiency in estimating the residual magnetic flux of the transformer. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0018] Figure 1 is a flow chart of a method for determining residual magnetic flux of a transformer according to an embodiment of the present invention;

[0019] Figure 2 is a flow chart of a method for building a power outage cycle database according to an embodiment of the present invention;

[0020] Figure 3 is a flow chart of a method for evaluating residual magnetic flux of a transformer according to an embodiment of the present invention;

[0021] Figure 4 is a flow chart of an application process of a method for evaluating residual magnetic flux of a transformer according to an embodiment of the present invention;

[0022] Figure 5 is a schematic diagram of wiring for a no-load test of a transformer according to an embodiment of the present invention;

[0023] Figure 6 is a schematic diagram of a change trend of magnetic flux during pre-magnetization training according to an embodiment of the present invention;

[0024] Figure 7 is a schematic diagram of a current signal at the moment of power failure according to an embodiment of the present invention;

[0025] Figure 8 is a schematic diagram of a fitting example according to an embodiment of the present invention;

[0026] Fig. 9 is a schematic diagram of another fitting example according to an embodiment of the present invention;

[0027] Fig.10 is a schematic diagram of a device for determining residual magnetic flux of a transformer according to an embodiment of the present invention. DETAILED DESCRIPTION

[0028] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only embodiments of a part of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0029] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0030] Example 1

[0031] According to an embodiment of the present invention, a method for determining the residual magnetic flux of a transformer is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0032] Figure 1 1 is a flow chart of a method for determining residual magnetic flux of a transformer according to an embodiment of the present invention. The method may include the following steps:

[0033] Step S101, obtaining a current signal generated by at least one transformer in a power grid at at least one node at the moment of power failure.

[0034] In the technical solution provided in the above step S101 of the present invention, the above current signal can be associated with the position of each node. For example, if the first distance between the first node and the transformer is less than the second distance between the second node and the transformer, the current signal generated by the transformer in the power grid at the first node at the moment of power failure is stronger than the current signal generated by the transformer in the power grid at the second node at the moment of power failure. This is only an example and is not specifically limited.

[0035] It should be noted that the above-mentioned first node and the above-mentioned second node are only used to distinguish different nodes, and are not used to limit the arrangement order of the nodes. The above-mentioned first distance and the above-mentioned second distance are only used to distinguish the positional relationship between the node and the transformer, and are not used to limit the distance between the node and the transformer.

[0036] Optionally, a current signal generated by at least one transformer in the power grid at at least one node at the moment of power failure is obtained. For example, when the transformer is at the moment of power failure, the current generated by the transformer at at least one node at the moment of power failure can be measured by a measuring device to obtain a current signal. For example, the above-mentioned measuring device can be any one of the following devices: an oscilloscope, a current sensor, etc., which are only used as examples here and are not specifically limited.

[0037] Step S102, determining a target current peak value from the current peak values ​​corresponding to the current signal.

[0038] In the technical solution provided in the above step S102 of the present invention, the above target current peak value can be used to represent each current peak value between adjacent cycles of the node at the moment of power failure.

[0039] In this embodiment, after obtaining the current signal generated by at least one transformer in the power grid at at least one node at the moment of power failure, the target current peak value is determined from the current peak values ​​corresponding to the current signal. For example, by performing waveform analysis on the obtained current signal, the current peak value corresponding to the current signal can be obtained, and then from the obtained current peak values, each current peak value between adjacent cycles of the node at the moment of power failure is selected as the target current peak value.

[0040] Optionally, by inputting the acquired current signal into a data analysis system for waveform analysis, a current peak value corresponding to the current signal can be obtained, wherein the data analysis system can be implemented based on a machine learning model, and the machine learning model can be but not limited to at least one of the following models: decision tree model, particle swarm model, support vector machine model, etc., which are only used as examples here without specific limitation.

[0041] Step S103 , performing linear fitting on the target current peak based on the fitting template, and obtaining the fitting goodness of fit between the original current signal and the fitting curve of the attenuation characteristic corresponding to the current signal.

[0042] In the technical solution provided in the above step S103 of the present invention, the above fitting template can be used to represent the rule for linear fitting of the target current peak value, the above fitting template can include at least a first fitting template and a second fitting template, the first fitting template can be a rule for product fitting of the target current peak value, and the second fitting template can be a rule for exponential fitting of the target current peak value. The above original current signal can be used to represent the current signal generated by the transformer at the node before the power-off moment, and the above original current signal can be associated with the position of each node. For example, if the first distance between the first node and the transformer is greater than the second distance between the second node and the transformer, then the current signal generated by the transformer in the power grid at the first node before the power-off moment is weaker than the current signal generated by the transformer in the power grid at the second node before the power-off moment. This is only an example and is not specifically limited.

[0043] It should be noted that the above-mentioned first node and the above-mentioned second node are only used to distinguish different nodes, and are not used to limit the arrangement order of the nodes. The above-mentioned first distance and the above-mentioned second distance are only used to distinguish the positional relationship between the node and the transformer, and are not used to limit the distance between the node and the transformer.

[0044] In this embodiment, after determining the target current peak value from the current peak value corresponding to the current signal, a linear fit is performed on the target current peak value based on a fitting template to obtain the goodness of fit of the original current signal and the fitting curve of the attenuation characteristic corresponding to the current signal. For example, based on the determined target current peak value, the attenuation coefficient of the acquired current signal between adjacent cycles is determined. Based on the attenuation coefficient of the current signal between adjacent cycles and the rule for linear fitting of the target current peak value, by performing linear fitting on the target current peak value, the goodness of fit of the original current signal and the fitting curve of the attenuation characteristic corresponding to the current signal can be obtained.

[0045] Step S104, in response to the goodness of fit exceeding the goodness of fit threshold, determining the residual magnetic flux of the transformer under the original current signal based on a preset database corresponding to the type of the transformer, wherein the preset database is used to store a mapping relationship between the original current signal and the residual magnetic flux.

[0046] In the technical solution provided in the above step S104 of the present invention, the above preset database can be used to store the mapping relationship between the original current signal and the residual magnetic flux.

[0047] In this embodiment, after linear fitting is performed on the target current peak based on the fitting template to obtain the goodness of fit of the original current signal and the fitting curve of the attenuation characteristic corresponding to the current signal, in response to the goodness of fit exceeding the goodness of fit threshold, the residual magnetic flux of the transformer under the original current signal is determined based on a preset database corresponding to the type of the transformer. For example, by judging the relationship between the goodness of fit obtained by fitting and the goodness of fit threshold, if it is judged that the goodness of fit exceeds the goodness of fit threshold, the residual magnetic flux of the transformer under the original current signal is determined according to the preset database corresponding to the type of the transformer. If it is judged that the goodness of fit exceeds the goodness of fit threshold, If the goodness of fit does not exceed the goodness of fit threshold, the fitting template currently used is switched to another fitting template, so as to use the other fitting template after switching to perform linear fitting on the target current peak, thereby obtaining the goodness of fit of the original current signal and the fitting curve of the attenuation characteristic corresponding to the current signal, and then judging the relationship between the goodness of fit obtained by fitting using the other fitting template after switching and the goodness of fit threshold, if it is judged that the goodness of fit obtained by fitting using the other fitting template after switching exceeds the goodness of fit threshold, then determining the residual magnetic flux of the transformer under the original current signal according to the preset database corresponding to the type of transformer.

[0048] In the above steps S101 to S104 of the present application, the current signal generated by at least one transformer in the power grid at at least one node at the moment of power failure is obtained, and then the target current peak value is determined from the current peak value corresponding to the generated current signal, that is, the current peak values ​​between adjacent cycles of the node at the moment of power failure are determined, and then according to the rule of linear fitting of the target current peak value, the goodness of fit of the original current signal and the fitting curve of the attenuation characteristic corresponding to the current signal can be obtained by linear fitting of the target current peak value, and the relationship between the goodness of fit and the goodness of fit threshold is judged. If it is judged that the obtained goodness of fit exceeds the goodness of fit threshold, the residual magnetic flux of the transformer under the original current signal is determined according to the preset database corresponding to the type of transformer, thereby achieving the purpose of determining a more detailed range of the residual magnetic flux, solving the technical problem of low efficiency in estimating the residual magnetic flux of the transformer, and achieving the technical effect of improving the efficiency in estimating the residual magnetic flux of the transformer.

[0049] The above method of this embodiment is further introduced below.

[0050] As an optional implementation method, step S103, based on the fitting template, linear fitting is performed on the target current peak to obtain the goodness of fit of the original current signal and the fitting curve of the attenuation characteristic corresponding to the current signal, including: based on the target current peak, determining the attenuation coefficient of the current signal between adjacent cycles; determining the average value of the attenuation coefficient; based on the fitting template, linear fitting is performed on the average value to obtain the goodness of fit.

[0051] In this embodiment, the above-mentioned fitting template may be the first fitting template or the second fitting template, which is merely used as an example and is not specifically limited.

[0052] In this embodiment, after determining the target current peak value from the current peak value corresponding to the current signal, the attenuation coefficient of the current signal between adjacent cycles is determined based on the target current peak value; the average value of the attenuation coefficient is determined; based on the fitting template, the average value is linearly fitted to obtain the goodness of fit. For example, the attenuation coefficient of the acquired current signal between adjacent cycles is determined based on the current peak values ​​between adjacent cycles of the determined node at the moment of power failure, and then the average value of the attenuation coefficient is determined. Then, according to the rule of linear fitting of the target current peak value, the linear fitting of the average value of the attenuation coefficient is performed to obtain the goodness of fit of the original current signal and the fitting curve of the attenuation characteristic corresponding to the current signal.

[0053] Optionally, the attenuation coefficient of the acquired current signal between adjacent cycles is determined according to each current peak value between adjacent cycles at the moment of power failure of the determined node, which can be achieved by the following formula (1):

[0054] Pm=Gm-Gm+1 (1)

[0055] Among them, P m It can be used to indicate the current signal I at the moment of power failure. 1j (t) Attenuation coefficient between adjacent cycles, G m Can be used to represent the current signal I 1j (t) The peak current value of the previous cycle in the adjacent cycle, G m+1 Can be used to represent the current signal I 1j (t) The current peak value of the next cycle in the adjacent cycles.

[0056] Optionally, determining the average value of the attenuation coefficient may be achieved by the following formula (2):

[0057]

[0058] in, It can be used to represent the average value set of attenuation characteristics under each DC current level.

[0059] As an optional implementation method, based on the fitting template, a linear fit is performed on the average value to obtain a goodness of fit, including: in response to the fitting template being a first fitting template, the average value is input into the first fitting template for linear fitting to obtain a first goodness of fit; in response to the fitting template being a second fitting template, the average value is input into the second fitting template for linear fitting to obtain a second goodness of fit.

[0060] In this embodiment, the above-mentioned goodness of fit may include at least a first goodness of fit and a second goodness of fit. The first goodness of fit may be used to represent the goodness of fit of a fitting curve of an original current signal and an attenuation characteristic under a first fitting template. The second goodness of fit may be used to represent the goodness of fit of a fitting curve of an original current signal and an attenuation characteristic under a second fitting template. The above-mentioned fitting template may include at least a first fitting template and a second fitting template. The first fitting template may be a rule for performing product fitting on a target current peak value, and the second fitting template may be a rule for performing exponential fitting on a target current peak value.

[0061] Optionally, after determining the average value of the attenuation coefficient, in response to the fitting template being the first fitting template, the average value is input into the first fitting template for linear fitting to obtain a first goodness of fit; in response to the fitting template being the second fitting template, the average value is input into the second fitting template for linear fitting to obtain a second goodness of fit. For example, by judging whether the fitting template is the first fitting template or the second fitting template, if the fitting template is judged to be the first fitting template, the average value of the attenuation coefficient is input into the first fitting template for linear fitting to obtain the first goodness of fit; if the fitting template is judged to be the second fitting template, the average value of the attenuation coefficient is input into the second fitting template for linear fitting to obtain the second goodness of fit.

[0062] As an optional implementation method, in response to the fitting template being a first fitting template, the average value is input into the first fitting template for linear fitting to obtain a first goodness of fit, including: in response to the fitting template being the first fitting template, the average value is input into the fitting model in the first fitting template for linear fitting to obtain an original current signal; and an error calculation is performed on the original current signal to obtain a first goodness of fit.

[0063] In this embodiment, the above error calculation may at least include square sum error calculation and root mean square error calculation.

[0064] In this embodiment, after determining the average value of the attenuation coefficient, in response to the fitting template being the first fitting template, the average value is input into the fitting model in the first fitting template for linear fitting to obtain the original current signal; an error calculation is performed on the original current signal to obtain a first goodness of fit. For example, when the fitting template is the first fitting template, the original current signal can be obtained by inputting the average value of the attenuation coefficient into the fitting model in the first fitting template for linear fitting, that is, the current signal generated by the transformer at the node before the moment of power failure can be obtained, and then the first goodness of fit can be obtained by performing an error calculation on the obtained original current signal.

[0065] Optionally, when the fitting template is the first fitting template, the original current signal can be obtained by inputting the average value of the attenuation coefficient into the fitting model in the first fitting template for linear fitting, which can be achieved by the following formula (3):

[0066]

[0067] Among them, I 2iDC (i=0.1,0.2,...,I em ) can be used to represent the DC current signal data set before the power failure moment, and a, b, and c can be used to represent constants under the fitting template.

[0068] Optionally, by performing error calculation on the obtained original current signal, the first goodness of fit can be obtained by the following equations (4) to (6):

[0069]

[0070]

[0071]

[0072] Among them, I 2iDC (i=0.1,0.2,...,I em ) can be used to represent the DC current signal data set before the power failure moment, a, b, c can be used to represent the constants under the fitting template, and α can be used to represent the first goodness of fit.

[0073] As an optional implementation method, in response to the fitting template being the second fitting template, the average value is input into the second fitting template for linear fitting to obtain a second goodness of fit, including: in response to the fitting template being the second fitting template, the average value is input into the fitting model in the second fitting template for linear fitting to obtain the original current signal; and error calculation is performed on the original current signal to obtain the second goodness of fit.

[0074] In this embodiment, after determining the average value of the attenuation coefficient, in response to the fitting template being the second fitting template, the average value is input into the fitting model in the second fitting template for linear fitting to obtain the original current signal; the error calculation is performed on the original current signal to obtain the second goodness of fit. For example, when the fitting template is the second fitting template, the original current signal can be obtained by inputting the average value of the attenuation coefficient into the fitting model in the second fitting template for linear fitting, that is, the current signal generated by the transformer at the node before the power-off moment can be obtained, and then the second goodness of fit can be obtained by performing error calculation on the obtained original current signal.

[0075] Optionally, when the fitting template is the second fitting template, the original current signal can be obtained by inputting the average value of the attenuation coefficient into the fitting model in the second fitting template for linear fitting, which can be achieved by the following formula (7):

[0076]

[0077] Among them, I 2iDC (i=0.1,0.2,...,I em ) can be used to represent the DC current signal data set before the power failure moment, and a, b, c, and d can be used to represent the constants under the fitting template.

[0078] As an optional implementation method, step S104, in response to the goodness of fit exceeding the goodness of fit threshold, based on a preset database corresponding to the type of transformer, determines the residual magnetic flux of the transformer under the original current signal, including: in response to the goodness of fit of the fitting curve of the original current signal and the attenuation characteristic under the first fitting template exceeding the goodness of fit threshold, or, in response to the goodness of fit of the fitting curve of the original current signal and the attenuation characteristic under the second fitting template exceeding the goodness of fit threshold, determines the original current value corresponding to the original current signal; in the preset database, determines the residual magnetic flux of the transformer under the original current value.

[0079] In this embodiment, after linear fitting is performed on the target current peak based on the fitting template to obtain the goodness of fit of the original current signal and the fitting curve of the attenuation characteristic corresponding to the current signal, the relationship between the goodness of fit obtained by fitting and the goodness of fit threshold is judged. If it is judged that the goodness of fit of the original current signal and the fitting curve of the attenuation characteristic under the first fitting template exceeds the goodness of fit threshold, the original current value corresponding to the original current signal is determined, and the residual magnetic flux mapped one-to-one with the original current value is searched in the preset database to obtain the residual magnetic flux of the transformer at the original current value. Alternatively, if it is judged that the goodness of fit of the original current signal and the fitting curve of the attenuation characteristic under the second fitting template exceeds the goodness of fit threshold, the original current value corresponding to the original current signal is determined, and the residual magnetic flux mapped one-to-one with the original current value is searched in the preset database to obtain the residual magnetic flux of the transformer at the original current value.

[0080] As an optional embodiment, the method also includes: in response to the goodness of fit of the fitting curve of the original current signal and the attenuation characteristic under the first fitting template not exceeding the goodness of fit threshold, determining the attenuation coefficient of the current signal between adjacent cycles; determining the average value of the attenuation coefficient; inputting the average value into the second fitting template for linear fitting to obtain a second goodness of fit; in response to the goodness of fit of the fitting curve of the original current signal and the attenuation characteristic under the second fitting template not exceeding the goodness of fit threshold, determining the attenuation coefficient of the current signal between adjacent cycles; determining the average value of the attenuation coefficient; inputting the average value into the first fitting template for linear fitting to obtain a first goodness of fit.

[0081] In this embodiment, by judging the relationship between the goodness of fit obtained by fitting and the goodness of fit threshold, if it is judged that the goodness of fit of the fitting curve of the original current signal and the attenuation characteristic under the first fitting template does not exceed the goodness of fit threshold, then the attenuation coefficient of the current signal between adjacent cycles is determined according to the determined target current peak value, and then the average value of the attenuation coefficient is determined, and the original current signal can be obtained by inputting the average value of the attenuation coefficient into the second fitting template for linear fitting, that is, the current signal generated by the transformer at the node before the power-off moment can be obtained, and then the second goodness of fit can be obtained by performing error calculation on the obtained original current signal.

[0082] In this embodiment, by judging the relationship between the goodness of fit obtained by fitting and the goodness of fit threshold, if it is judged that the goodness of fit of the fitting curve of the original current signal and the attenuation characteristic under the second fitting template does not exceed the goodness of fit threshold, then the attenuation coefficient of the current signal between adjacent cycles is determined according to the determined target current peak value, and then the average value of the attenuation coefficient is determined, and the original current signal can be obtained by inputting the average value of the attenuation coefficient into the first fitting template for linear fitting, that is, the current signal generated by the transformer at the node before the power-off moment can be obtained, and then the first goodness of fit can be obtained by performing error calculation on the obtained original current signal.

[0083] In this embodiment, a current signal generated by at least one transformer in the power grid at at least one node at the moment of power failure is obtained, and then a target current peak value is determined from the current peak value corresponding to the generated current signal, that is, each current peak value between adjacent cycles of the node at the moment of power failure is determined, and then according to the rule of linear fitting of the target current peak value, a linear fitting of the target current peak value is performed to obtain the goodness of fit of the original current signal and the fitting curve of the attenuation characteristic corresponding to the current signal, and by judging the relationship between the goodness of fit and the goodness of fit threshold, if it is judged that the obtained goodness of fit exceeds the goodness of fit threshold, the residual magnetic flux of the transformer under the original current signal is determined according to a preset database corresponding to the type of transformer, thereby achieving the purpose of determining a more detailed range of the residual magnetic flux, solving the technical problem of low efficiency in estimating the residual magnetic flux of the transformer, and achieving the technical effect of improving the efficiency in estimating the residual magnetic flux of the transformer.

[0084] Example 2

[0085] The technical solution of the embodiment of the present invention is illustrated below in conjunction with preferred implementation modes.

[0086] In the power system, due to the residual magnetism of the iron core in the transformer, a large excitation surge current will be generated on one side of the transformer when the transformer is closed. Therefore, the estimation of residual magnetism is particularly important. However, at this stage, the detection methods for the residual magnetism of the iron core in the transformer are generally empirical methods, pre-magnetization methods, etc. In the empirical method, the transformer is analyzed after the switch is opened, and then a relatively wide residual magnetism range is judged. This method cannot accurately meet the estimation requirements of the residual magnetism range. In the pre-magnetization method, the residual magnetism of the iron core is measured by DC voltage excitation. Although this method has measured the residual magnetism value, it has changed the residual magnetism inside the iron core. At the same time, a large current is required to generate a saturation flux. It is not suitable for actual engineering applications, resulting in a technical problem of low efficiency in estimating the residual flux of the transformer.

[0087] However, an embodiment of the present invention proposes a method for determining the residual magnetism of a transformer. By establishing a complete power-off cycle database information and evaluating the residual magnetism content through the power-off instantaneous current signal collected during on-site operations, the purpose of determining a more detailed range of residual magnetic flux is achieved, the technical problem of low efficiency in estimating the residual magnetic flux of the transformer is solved, and the technical effect of improving the efficiency of estimating the residual magnetic flux of the transformer is achieved.

[0088] Figure 2 is a flow chart of a method for building a power failure cycle database according to an embodiment of the present invention. Figure 2 As shown, the method may include the following steps:

[0089] Step S201, calibrate the experimental circuit.

[0090] In the technical solution provided in step S201 of the present invention, the calibrated experimental circuit can be as follows: Figure 5 shown.

[0091] Figure 5 is a schematic diagram of wiring for a no-load test of a transformer according to an embodiment of the present invention, such as Figure 5 As shown, when the detection object is a 220V single-phase transformer, switch S1 is turned on and 0.1A I is input to the secondary side of the transformer. 2DC , use a voltage regulator to adjust the primary voltage to the rated primary voltage U of the transformer 1N In addition, the controlled DC current source is adjusted, and the secondary current starts from 0.1A and increases by 0.1A repeatedly until the secondary current is adjusted to the excitation current I em value.

[0092] In this embodiment, the DC power supply is calibrated, for example, the DC power supply used is set as a voltage-controlled current source, wherein the voltage and current values ​​can be U Ie ,I e ; Calibrate the equivalent resistance R1. For example, by comparing the transformer nameplate data, calibrate the equivalent line resistance R1 value. When the transformer primary-secondary ratio k is determined, U 2N =U 1N / k,U 2N / R1<=10%*I em ; Adjust the resistor R2, for example, according to the equivalent line resistance R1, adjust the resistor R2 according to the relationship R2 = 0.1 * R1 to weaken the AC signal U in the secondary circuit 2N For DC signal U Ie and I e The protection resistor R3, for example, is determined based on the actual controlled source, and the protection resistor R3 is R3 = U Ie / Ie -LR2, where L can be determined based on the selected controlled source capacity, and its value can be any value between 1 and 10.

[0093] Step S202, calibrating the signal acquisition standard.

[0094] In the technical solution provided in the above step S202 of the present invention, after calibrating the experimental circuit, the signal acquisition standard is calibrated.

[0095] Step S203, collecting the current waveform of the transformer before power failure.

[0096] In the technical solution provided in the above step S203 of the present invention, after the signal collection standard is calibrated, the current waveform of the transformer before power failure is collected.

[0097] Step S204, comparing the magnetic flux (B)-magnetic field strength (H) curve, complete the simulation residual magnetic intensity estimation.

[0098] In the technical solution provided in the above step S204 of the present invention, after collecting the current waveform of the transformer before power failure, the simulation residual magnetic intensity estimation is completed by comparing with the BH curve.

[0099] Step S205, collecting the current waveform of the transformer at the moment of power failure.

[0100] In the technical solution provided in the above step S205 of the present invention, after the simulation of residual magnetic intensity estimation is completed for the BH curve, the current waveform of the transformer at the moment of power failure is collected.

[0101] Step S206, extracting the attenuation characteristic set P of the current signal m .

[0102] In the technical solution provided in step S206 of the present invention, after collecting the current waveform of the transformer at the moment of power failure, the attenuation characteristic set P of the current signal is extracted. m For example, through formula (1), the attenuation characteristic set P of the current signal can be extracted m .

[0103] Step S207, extracting the attenuation characteristic average value set

[0104] In the technical solution provided in step S207 of the present invention, when extracting the attenuation characteristic set P of the current signal m Afterwards, extract the mean value set of attenuation characteristics For example, by using formula (2), the attenuation characteristic average value set can be extracted:

[0105]

[0106] Step S208: performing linear fitting on the attenuation characteristic data set.

[0107] In the technical solution provided in step S208 of the present invention, when extracting the average value set of attenuation characteristics, Afterwards, a linear fit is performed on the decay characteristic data set.

[0108] In this embodiment, the superimposed video data R1 is synchronously transmitted to the operator's on-site terminal and the relay protection expert workstation, and the superimposed video data R1 is displayed on the operator's on-site terminal and the relay protection expert workstation, so that both parties can simultaneously visualize the interactive results.

[0109] Step S209: extracting the goodness-of-fit characterization value of the fitting curve.

[0110] In the technical solution provided in the above step S209 of the present invention, after linear fitting is performed on the attenuation characteristic data set, the fitting goodness characterization quantity of the fitting curve is extracted, for example, the sum of squares error EP1 and the root mean square error EP2 are extracted.

[0111] In this embodiment, after the expert or operator hangs up the real-time communication of the guidance process, the superimposed video data R1 is saved in the relay protection operation information library. In addition, the superimposed video data R1 can be classified as a typical case or archived in daily operations as needed.

[0112] Step S210, determining whether EP2 / EP1 is greater than 1.5.

[0113] In the technical solution provided in the above step S210 of the present invention, after extracting the goodness-of-fit characterization quantity of the fitting curve, the goodness-of-fit characterization quantity of the fitting curve is extracted. For example, by using formula (4) and formula (5), the sum of squares error EP1 and the root mean square error EP2 can be extracted respectively.

[0114] If EP2 / EP1 is greater than 1.5, the process proceeds to step S211 and selects fitting formula (3); if EP2 / EP1 is less than 1.5, the process proceeds to step S212 and selects fitting formula (7).

[0115] In this embodiment, if EP2 / EP1 is greater than 1.5, it means that the fitting formula (3) can be selected for fitting, and the goodness of fit of the fitting curve obtained by the fitting also meets the error criterion. If EP2 / EP1 is less than 1.5, it means that the fitting formula (3) cannot be selected for fitting, and the fitting formula (7) must be selected for fitting, and the goodness of fit of the fitting curve obtained by the fitting meets the error criterion.

[0116] After selecting fitting formula (3) or fitting formula (7), the process proceeds to step S213 to output the best fitting result.

[0117] After the best fitting result is output, the process proceeds to step S214 to complete the construction of the power outage cycle database.

[0118] Figure 3 is a flow chart of a method for evaluating residual magnetic flux of a transformer according to an embodiment of the present invention. Figure 3 As shown, the method may include the following steps:

[0119] Step S301, training the transformer for pre-magnetization.

[0120] In the technical solution provided in step S301 of the present invention, the change trend of transformer pre-magnetization can be as follows: Figure 6 As shown, Figure 6 is a schematic diagram of a pre-magnetization training magnetic flux change trend according to an embodiment of the present invention. First, a calibrated DC current I is input to the secondary side. 2DC Due to the effect of DC excitation, the magnetic flux of the core will be on the BH curve (H DC , B DC ) point. When AC power I is input to the primary side of the transformer 1AC When the secondary DC I 2DC The input is used to simulate the bias magnetism in the pre-magnetization training process. 2DC calibration to simulate the dynamic characteristics under different bias magnetization / remanent magnetization.

[0121] In this embodiment, the current signal I i The total acquisition time T of (t) must be greater than 0.2s, and the current signal I i The number of cycles N of (t) must be greater than 10.

[0122] Step S302, building a power outage cycle database.

[0123] In the technical solution provided in the above step S302 of the present invention, after training the transformer pre-magnetization, a power-off cycle database is built.

[0124] In this embodiment, a power failure cycle database is established for various types of transformers, and a no-load test needs to be performed on the transformers.

[0125] Step S303, collecting on-site current signals.

[0126] In the technical solution provided in step S303 of the present invention, after the power failure cycle database is built, the on-site current signal is collected, and the current signal I at the moment of power failure is calculated. 1j (t) Perform data processing, for example, taking the peak current of each cycle as G1 to GN .

[0127] Step S304, estimating the residual magnetic flux of the transformer.

[0128] In the technical solution provided in the above step S304 of the present invention, after collecting the field current signal, the residual magnetic flux of the transformer.

[0129] Step S305, outputting the estimation result of the residual magnetic flux.

[0130] In the technical solution provided in the above step S305 of the present invention, after estimating the residual magnetic flux of the transformer, the estimation result of the residual magnetic flux is output.

[0131] In this embodiment, internal associations are established based on the extracted relay protection operation objects, and three-dimensional models, historical operation records, defects and fault records corresponding to the relay protection operation objects are pre-extracted, and historical operation records are extracted from data storage.

[0132] Figure 4 is a flow chart of an application process of a method for evaluating residual magnetic flux of a transformer according to an embodiment of the present invention. Figure 4 As shown, the method may include the following steps:

[0133] Step S401, collecting the instantaneous current signal of power failure.

[0134] In the technical solution provided in the above step S401 of the present invention, the relay protection operation information library can receive the issued operation ticket.

[0135] Step S402: Calculate the average value of the attenuation characteristics of the nodes after N / 2

[0136] In the technical solution provided in step S402 of the present invention, after collecting the instantaneous current signal of power failure, the average value of the attenuation characteristics of the nodes after N / 2 is calculated.

[0137] Step S403, calculating the DC current signal data set I before the power failure instant according to the best fitting formula 2iDC .

[0138] In the technical solution provided in step S403 of the present invention, after calculating N / 2, the average value of the attenuation characteristic of the node Then, according to the best fitting formula, the DC current signal data set I before the power failure moment is calculated. 2iDC .

[0139] In this embodiment, internal associations are established based on the extracted relay protection operation objects, and three-dimensional models, historical operation records, defects and fault records corresponding to the relay protection operation objects are pre-extracted, and historical operation records are extracted from data storage.

[0140] Step S404, referring to the established power-off cycle database, the residual magnetic flux is estimated.

[0141] In the technical solution provided in step S404 of the present invention, the DC current signal data set I before the power failure moment is calculated according to the best fitting formula. 2iDC Afterwards, the residual magnetic flux is estimated by referring to the established power-off cycle database.

[0142] In this embodiment, internal associations are established based on the extracted relay protection operation objects, and three-dimensional models, historical operation records, defects and fault records corresponding to the relay protection operation objects are pre-extracted, and historical operation records are extracted from data storage.

[0143] Step S405, outputting the estimation result of the residual magnetic flux.

[0144] In the technical solution provided in the above step S405 of the present invention, the residual magnetic flux estimation is performed by referring to the established power-off cycle database. 2iDC After that, the estimation result of the residual magnetic flux is output.

[0145] In this embodiment, internal associations are established based on the extracted relay protection operation objects, and three-dimensional models, historical operation records, defects and fault records corresponding to the relay protection operation objects are pre-extracted, and historical operation records are extracted from data storage.

[0146] Figure 6 is a schematic diagram of a pre-magnetization training magnetic flux change trend according to an embodiment of the present invention, such as Figure 6 As shown, first, a calibrated DC current I is input into the secondary side. 2DC Due to the effect of DC excitation, the magnetic flux of the core will be on the BH curve (H DC , B DC ) point. When AC power I is input to the primary side of the transformer 1AC When the secondary DC I 2DC The input is used to simulate the bias magnetism in the pre-magnetization training process. 2DC calibration to simulate the dynamic characteristics under different bias magnetization / remanent magnetization.

[0147] In this embodiment, the current signal I iThe total acquisition time T of (t) must be greater than 0.2s, and the current signal I i The number of cycles N of (t) must be greater than 10.

[0148] Figure 7 is a schematic diagram of a current signal at the moment of power failure according to an embodiment of the present invention, such as Figure 7 As shown, in the collection of the analog data of the residual magnetic flux characteristics, the secondary DC current is instantaneously cut off to realize the collection of sample data. For example, the current signal I before the secondary side of the transformer is powered off is first collected. 2DC , according to the BH relationship curve of the transformer itself, the equivalent simulated residual magnetic intensity is calculated; after the switch S1 is disconnected, the DC excitation power supply on the secondary side will be cut off, and the simulated residual magnetic intensity will begin to decay. At this time, the instantaneous current signal I 1j (t), by the current signal I 1j By analyzing the changing law of (t), the attenuation characteristics of the simulated residual magnetism intensity can be obtained, which can be further used to analyze the influence of the residual magnetism on the closing current at the moment of closing.

[0149] In this embodiment, according to the DC current signal data set I before the power failure moment 2iDC (t), the estimation method of the residual magnetic strength can be simulated and calibrated, wherein the relationship between the excitation current and the simulated residual magnetic strength can be described by the following formula (8):

[0150]

[0151] Among them, N can be used to represent the number of coil turns, H can be used to represent the magnetic field strength, l can be used to represent the average magnetic path length, S can be used to represent the cross-sectional area of ​​the magnetic core, and μ can be used to represent the magnetic permeability of the iron core.

[0152] Optionally, firstly, a power-off cycle current signal database is built for the transformer of this type, and after the power-off cycle database is built, the current signal I before the power-off moment is 2iDC (t) and the current signal I at the moment of power failure 1j (t) Perform data processing. In actual field applications, considering the influence of the closing angle on the residual magnetism of the transformer core, the peak value of the cyclic current after N / 2 can be taken for linear fitting to obtain the corresponding attenuation characteristic value of the current, and finally the simulated residual magnetism intensity calibration under pre-magnetization training is completed by comparing the BH curve. Finally, the residual magnetic flux detection stage of this type of transformer begins.

[0153] For example, the residual magnetic flux of three transformers of the same model is estimated. After transformers No. 1 to No. 3 are operated at rated conditions for a period of time, they are tested by DC demagnetization method and run at different DC voltage source durations. No-load tests are performed on transformers No. 1 to No. 3 respectively, and the current signals of transformers No. 1 to No. 3 under the instant of power failure are collected as I 1j (t)(i=1, 2, 3), the current signal of transformers No. 1 to No. 3 to be tested at the moment of power failure is I 1j (t) Data screening is performed, and the peak value after N / 2 is selected to calculate the attenuation characteristics. The calculation shows that the average values ​​of the attenuation characteristics of the currents of transformers No. 1 to No. 3 to be tested are respectively

[0154] After calculating the average value of the attenuation characteristics of the current of transformers 1 to 3, according to the established power-off cycle current signal database of this type of transformer and the attenuation characteristic characterization curve of this type of transformer under the pre-magnetization training of the iron core (such as Figure 8 As shown), the fitting formula (3) can be obtained as: The goodness of fit characterizations of the fitting formula are: EP1 = 0.050, EP2 = 0.065. Since EP2 / EP1 = 1.3 < 1.5, it can be seen that the fitting formula cannot achieve effective fitting. Therefore, the fitting formula (7) is adopted as follows: EP1=0.037,EP2=0.058,then EP2 / EP1=1.57>1.5 shows that the fitting formula can achieve effective fitting. The goodness of fit obtained by this fitting meets the accuracy requirements. Its attenuation characteristic characterization curve can be shown as Fig. 9 shown.

[0155] Figure 8 is a schematic diagram of a fitting example according to an embodiment of the present invention, such as Figure 8 The figure shows a fitting example obtained by fitting using the fitting formula (3).

[0156] Fig. 9 is a schematic diagram of another fitting example according to an embodiment of the present invention, such as Fig. 9 The figure shows a fitting example obtained by fitting formula (7).

[0157] In this embodiment, the experimental circuit and signal acquisition standard are calibrated, the current waveform of the transformer before power failure is collected, and then the BH curve is used to complete the simulation of residual magnetic strength estimation, and then the current waveform of the transformer at the moment of power failure is collected to extract the attenuation characteristic set P of the current signal. m , extract the mean value set of attenuation characteristics And perform linear fitting on the attenuation characteristic data set, then extract the fitting curve fitting goodness characterization quantity, by judging whether the fitting curve fitting goodness characterization quantity exceeds the fitting goodness threshold, the selected fitting formula can be determined, and the best fitting result can be output, thereby achieving the purpose of determining a more detailed range of residual magnetic flux, solving the technical problem of low efficiency in estimating the residual magnetic flux of the transformer, and realizing the technical effect of improving the efficiency of estimating the residual magnetic flux of the transformer.

[0158] Example 3

[0159] According to an embodiment of the present invention, a device for determining the residual magnetic flux of a transformer is also provided. It should be noted that the device for determining the residual magnetic flux of a transformer can be used to execute a method for determining the residual magnetic flux of a transformer in embodiment 1.

[0160] Fig.10 Schematic diagram of a device for determining residual magnetic flux of a transformer according to an embodiment of the present invention. Fig.10 As shown, the device 1000 for determining the residual magnetic flux of the transformer may include: an acquisition unit 1001 , a determination unit 1002 , a fitting unit 1003 and a response unit 1004 .

[0161] The acquisition unit 1001 is used to acquire a current signal generated by at least one transformer in the power grid at at least one node at the moment of power failure.

[0162] The determination unit 1002 is used to determine a target current peak value from the current peak values ​​corresponding to the current signal, wherein the target current peak value is used to represent each current peak value between adjacent cycles of the node at the moment of power failure.

[0163] The fitting unit 1003 is used to perform linear fitting on the target current peak based on the fitting template to obtain the goodness of fit of the original current signal and the fitting curve of the attenuation characteristic corresponding to the current signal, wherein the fitting template is used to represent the rule for linear fitting of the target current peak, and the original current signal is used to represent the current signal generated by the transformer at the node before the power-off moment.

[0164] The response unit 1004 is used to determine the residual magnetic flux of the transformer under the original current signal in response to the goodness of fit exceeding the goodness of fit threshold based on a preset database corresponding to the type of the transformer, wherein the preset database is used to store the mapping relationship between the original current signal and the residual magnetic flux.

[0165] Optionally, the fitting unit 1003 may include: a first determination module, used to determine the attenuation coefficient of the current signal between adjacent cycles based on the target current peak; a second determination module, used to determine the average value of the attenuation coefficient; and a fitting module, used to perform linear fitting on the average value based on a fitting template to obtain a goodness of fit.

[0166] Optionally, the fitting module may include: a first fitting submodule, used to respond to the fitting template being the first fitting template, input the average value into the first fitting template for linear fitting, and obtain a first goodness of fit, wherein the first goodness of fit is used to represent the goodness of fit of the fitting curve of the original current signal and the attenuation characteristic under the first fitting template; a second fitting submodule, used to respond to the fitting template being the second fitting template, input the average value into the second fitting template for linear fitting, and obtain a second goodness of fit, wherein the second goodness of fit is used to represent the goodness of fit of the fitting curve of the original current signal and the attenuation characteristic under the second fitting template, and the fitting goodness includes the first goodness of fit and the second goodness of fit.

[0167] Optionally, the first fitting submodule can respond to the fitting template being the first fitting template by executing the following steps, inputting the average value into the first fitting template for linear fitting to obtain a first goodness of fit: responding to the fitting template being the first fitting template, inputting the average value into the fitting model in the first fitting template for linear fitting to obtain an original current signal; performing error calculation on the original current signal to obtain a first goodness of fit.

[0168] Optionally, the second fitting submodule can respond to the fitting template being the second fitting template by executing the following steps, inputting the average value into the second fitting template for linear fitting to obtain a second goodness of fit: responding to the fitting template being the second fitting template, inputting the average value into the fitting model in the second fitting template for linear fitting to obtain an original current signal; performing error calculation on the original current signal to obtain a second goodness of fit.

[0169] Optionally, the response unit 1004 may include: a response module, used to determine the original current value corresponding to the original current signal in response to the goodness of fit of the fitting curve of the original current signal and the attenuation characteristic under the first fitting template exceeding the goodness of fit threshold, or in response to the goodness of fit of the fitting curve of the original current signal and the attenuation characteristic under the second fitting template exceeding the goodness of fit threshold; a third determination module, used to determine the residual magnetic flux of the transformer under the original current value in a preset database.

[0170] Optionally, the device 1000 for determining the residual magnetic flux of the transformer may further include: a first fitting unit, for determining the attenuation coefficient of the current signal between adjacent cycles in response to the goodness of fit of the fitting curve of the original current signal and the attenuation characteristic under the first fitting template not exceeding the goodness of fit threshold; determining the average value of the attenuation coefficient; inputting the average value into the second fitting template for linear fitting to obtain a second goodness of fit, wherein the second goodness of fit is used to represent the goodness of fit of the fitting curve of the original current signal and the attenuation characteristic under the second fitting template; a second fitting unit, for determining the attenuation coefficient of the current signal between adjacent cycles in response to the goodness of fit of the fitting curve of the original current signal and the attenuation characteristic under the second fitting template not exceeding the goodness of fit threshold; determining the average value of the attenuation coefficient; inputting the average value into the first fitting template for linear fitting to obtain a first goodness of fit, wherein the first goodness of fit is used to represent the goodness of fit of the fitting curve of the original current signal and the attenuation characteristic under the first fitting template.

[0171] In this embodiment, an acquisition unit is used to acquire a current signal generated by at least one transformer in a power grid at at least one node at the moment of power failure; a determination unit is used to determine a target current peak value from current peak values ​​corresponding to the current signal, wherein the target current peak value is used to represent each current peak value between adjacent cycles of the node at the moment of power failure; a fitting unit is used to perform linear fitting on the target current peak value based on a fitting template to obtain a fitting goodness of fit of a fitting curve of an original current signal and an attenuation characteristic corresponding to the current signal, wherein the fitting template is used to represent a rule for performing linear fitting on the target current peak value, and the original current signal is used to represent a current signal generated by the transformer at the node before the moment of power failure; a response unit is used to determine the residual magnetic flux of the transformer under the original current signal based on a preset database corresponding to the type of the transformer in response to the fitting goodness exceeding a fitting goodness threshold, wherein the preset database is used to store a mapping relationship between the original current signal and the residual magnetic flux, thereby achieving the purpose of being able to determine a more refined range of the residual magnetic flux, solving the technical problem of low efficiency in estimating the residual magnetic flux of the transformer, and achieving a technical effect of improving the efficiency in estimating the residual magnetic flux of the transformer.

[0172] Example 4

[0173] According to an embodiment of the present invention, a computer-readable storage medium is further provided. The storage medium includes a stored program, wherein the program executes the method for determining the residual magnetic flux of the transformer in Embodiment 1.

[0174] Example 5

[0175] According to an embodiment of the present invention, a processor is further provided, the processor being used to run a program, wherein the program executes the method for determining the residual magnetic flux of the transformer in Embodiment 1 when the program is run by the processor.

[0176] Example 6

[0177] According to an embodiment of the present invention, a computer program product is further provided. The computer program product includes a computer program. When the computer program is executed by a processor, the method for determining the residual magnetic flux of the transformer in Embodiment 1 of the present invention is implemented.

[0178] The serial numbers of the above embodiments of the present invention are only for description and do not represent the advantages or disadvantages of the embodiments.

[0179] In the above embodiments of the present invention, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0180] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. Among them, the device embodiments described above are only schematic. For example, the division of units can be a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of units or modules, which can be electrical or other forms.

[0181] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed over multiple units. Some or all of the units may be selected according to actual needs to achieve the purpose of the present embodiment.

[0182] 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.

[0183] 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, or the part that contributes to the relevant technology, or all or part of the technical solution can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, server or network device, etc.) to perform all or part of the steps of the methods of each embodiment of the present invention. The aforementioned storage medium includes: U disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), mobile hard disk, magnetic disk or optical disk and other media that can store program codes.

[0184] The above are only preferred embodiments of the present invention. It should be pointed out that, for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for determining the residual magnetic flux of a transformer, characterized in that: include: Acquire a current signal generated by at least one transformer in the power grid at at least one node at the moment of power failure; Determine a target current peak value from the current peak values ​​corresponding to the current signal, wherein the target current peak value is used to represent each current peak value of the node between adjacent cycles at the moment of the power failure; Based on the target current peak value, determining the attenuation coefficient of the current signal between the adjacent cycles; determining the average value of the attenuation coefficient; based on the fitting template, performing linear fitting on the average value and the actual value of the original current signal to obtain a goodness of fit, including: in response to the fitting template being a first fitting template, inputting the average value and the actual value of the original current signal into the first fitting template for linear fitting to obtain a first goodness of fit, wherein the first goodness of fit is used to represent the goodness of fit of a fitting curve of the actual value of the original current signal and the attenuation coefficient under the first fitting template; in response to the fitting template being a second fitting template, inputting the average value and the actual value of the original current signal into the second fitting template for linear fitting to obtain a second goodness of fit, wherein the second goodness of fit is used to represent the goodness of fit of a fitting curve of the actual value of the original current signal and the attenuation coefficient under the second fitting template, and the goodness of fit includes the first goodness of fit and the second goodness of fit; In response to the goodness of fit exceeding a goodness of fit threshold, determining a residual magnetic flux of the transformer under the original current signal based on a preset database corresponding to the type of the transformer, wherein the preset database is used to store a mapping relationship between the original current signal and the residual magnetic flux; Wherein, in response to the goodness of fit exceeding the goodness of fit threshold, determining the residual magnetic flux of the transformer under the original current signal based on a preset database corresponding to the type of the transformer, includes: in response to the first goodness of fit exceeding the goodness of fit threshold, or in response to the second goodness of fit exceeding the goodness of fit threshold, determining the fitting value of the original current signal; determining the residual magnetic flux of the transformer under the fitting value of the original current signal in the preset database; The method further includes: in response to the first goodness of fit not exceeding the goodness of fit threshold, determining the second goodness of fit; or, in response to the second goodness of fit not exceeding the goodness of fit threshold, determining the first goodness of fit.

2. The method according to claim 1, characterized in that In response to the fitting template being a first fitting template, inputting the average value and the actual value of the original current signal into the first fitting template for linear fitting to obtain a first goodness of fit, including: In response to the fitting template being the first fitting template, inputting the average value and the actual value of the original current signal into a fitting model in the first fitting template for linear fitting to obtain a fitting value of the original current signal; An error calculation is performed on the fitting value of the original current signal to obtain the first goodness of fit.

3. The method according to claim 1, characterized in that In response to the fitting template being a second fitting template, inputting the average value and the actual value of the original current signal into the second fitting template for linear fitting to obtain a second goodness of fit, including: In response to the fitting template being the second fitting template, inputting the average value and the actual value of the original current signal into a fitting model in the second fitting template for linear fitting to obtain a fitting value of the original current signal; An error calculation is performed on the fitting value of the original current signal to obtain the second goodness of fit.

4. A device for determining residual magnetic flux of a transformer, characterized in that: include: An acquisition unit, used for acquiring a current signal generated by at least one transformer in the power grid at at least one node at the moment of power failure; A determination unit, configured to determine a target current peak value from the current peak values ​​corresponding to the current signal, wherein the target current peak value is used to represent each current peak value of the node between adjacent cycles at the instant of the power failure; A fitting unit, for determining, based on the target current peak value, an attenuation coefficient of the current signal between the adjacent cycles; determining an average value of the attenuation coefficient; and performing linear fitting on the average value and the actual value of the original current signal based on a fitting template to obtain a goodness of fit, comprising: in response to the fitting template being a first fitting template, inputting the average value and the actual value of the original current signal into the first fitting template for linear fitting to obtain a first goodness of fit, wherein the first goodness of fit is used to represent the goodness of fit of a fitting curve of the actual value of the original current signal and the attenuation coefficient under the first fitting template; in response to the fitting template being a second fitting template, inputting the average value and the actual value of the original current signal into the second fitting template for linear fitting to obtain a second goodness of fit, wherein the second goodness of fit is used to represent the goodness of fit of a fitting curve of the actual value of the original current signal and the attenuation coefficient under the second fitting template, and the goodness of fit includes the first goodness of fit and the second goodness of fit; a response unit, configured to determine, in response to the goodness of fit exceeding a goodness of fit threshold, a residual magnetic flux of the transformer under the original current signal based on a preset database corresponding to the type of the transformer, wherein the preset database is used to store a mapping relationship between the original current signal and the residual magnetic flux; Wherein, the response unit is used to determine the residual magnetic flux of the transformer under the original current signal based on a preset database corresponding to the type of the transformer in response to the goodness of fit exceeding the goodness of fit threshold by performing the following steps: in response to the first goodness of fit exceeding the goodness of fit threshold, or in response to the second goodness of fit exceeding the goodness of fit threshold, determine the fitting value of the original current signal; in the preset database, determine the residual magnetic flux of the transformer under the fitting value of the original current signal; The device is also used to perform the following steps: in response to the first goodness of fit not exceeding the goodness of fit threshold, determining the second goodness of fit; or, in response to the second goodness of fit not exceeding the goodness of fit threshold, determining the first goodness of fit.

5. 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 method for determining the residual magnetic flux of the transformer according to any one of claims 1 to 3.

6. A processor, characterized in that: The processor is used to run a program, wherein the program, when run by the processor, executes the method for determining the residual magnetic flux of the transformer according to any one of claims 1 to 3.

7. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the method for determining the residual magnetic flux of the transformer according to any one of claims 1 to 3 is implemented.

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