Method and apparatus for adjusting three-phase current imbalance of distribution transformer

Abstract

The present invention provides a method for adjusting three-phase current imbalance of a distribution transformer. The method comprises: acquiring time-series three-phase current values and a balance coefficient threshold of a distribution transformer; normalizing the three-phase current values at each moment, sorting the current values of the phases among the normalized three-phase current values, and recording the positions of the current values of the phases; on the basis of the balance coefficient threshold, calculating a balance maximum value and a balance minimum value at each moment, and on the basis of the balance maximum value and the balance minimum value, adjusting the three-phase current values of the corresponding moment, so that the three-phase current values fall between the balance maximum value and the balance minimum value, wherein the sum of the three-phase current values at each moment before and after adjustment is kept unchanged; and on the basis of the positions of the current values, restoring the adjusted three-phase current values.

Description

Method and device for regulating three-phase current imbalance of distribution transformer Technical Field

[0001] The present invention mainly relates to the field of power digitalization, and in particular to a method and device for regulating three-phase current imbalance of a distribution transformer. Background Art

[0002] In a three-phase distribution transformer, unbalanced current refers to the absolute value of the difference between the A, B, and C phase currents and their average value, divided by the average value. If the unbalanced current exceeds a threshold, that point in the distribution transformer is considered unbalanced. If the total number of unbalanced points within a given period exceeds a certain ratio, the distribution transformer is considered unbalanced. An unbalanced distribution transformer can be hazardous to the transformer and severely damage the entire power grid.

[0003] Currently, removing the imbalance of distribution transformers mainly relies on manual operation by experienced electrical engineers, which is time-consuming and inefficient.

[0004] Summary of the Invention

[0005] In order to solve the above technical problems, the present invention provides a method and device for regulating three-phase current imbalance of a distribution transformer, so as to realize automatic regulation of three-phase current imbalance of the distribution transformer and improve regulation efficiency.

[0006] To achieve the above object, the present invention proposes a method for regulating three-phase current imbalance of a distribution transformer, the method comprising:

[0007] Obtain the time-series three-phase current value and balance coefficient threshold of the distribution transformer;

[0008] Normalize the three-phase current values ​​at each moment, sort the current values ​​of each phase in the normalized three-phase current values, and record the position of each phase current value;

[0009] Calculating a maximum balance value and a minimum balance value at each time point according to the balance coefficient threshold, and adjusting the three-phase current value at the corresponding time point according to the maximum balance value and the minimum balance value so that the three-phase current value falls between the maximum balance value and the minimum balance value, wherein the sum of the three-phase current values ​​before and after the adjustment at each time point remains unchanged;

[0010] The adjusted three-phase current values ​​are restored according to the positions of the current values.

[0011] To this end, the maximum and minimum balance values ​​are determined by the balance coefficient threshold, and the three-phase current values ​​are adjusted so that the three-phase current values ​​fall between the maximum and minimum balance values, thereby making the three-phase current in a balanced state, realizing automatic adjustment of the three-phase current imbalance of the distribution transformer and improving the adjustment efficiency.

[0012] Optionally, adjusting the three-phase current values ​​at corresponding time points according to the balanced maximum value and the balanced minimum value so that the three-phase current values ​​fall between the balanced maximum value and the balanced minimum value includes: determining whether the current maximum value among the three-phase current values ​​is greater than the balanced maximum value; if the current maximum value among the three-phase current values ​​is greater than the balanced maximum value, using a right operator to adjust the three-phase current values; wherein using the right operator to adjust the three-phase current values ​​includes: calculating a difference between the current maximum value and the balanced maximum value, subtracting the difference from the current maximum value, and adding the difference to the current minimum value among the three-phase current values; and

[0013] Determine whether the minimum current value among the three-phase current values ​​is less than the balanced minimum value. If the minimum current value among the three-phase current values ​​is less than the balanced minimum value, use the left operator to adjust the three-phase current values; wherein, using the left operator to adjust the three-phase current values ​​includes: calculating the difference between the minimum current value and the balanced minimum value, adding the difference to the minimum current value, and subtracting the difference from the maximum current value among the three-phase current values.

[0014] To this end, the three-phase current values ​​are adjusted to between the balanced maximum value and the balanced minimum value through the left operator and the right operator, that is, the three-phase current is balanced.

[0015] Optionally, the method further includes calculating an unbalance coefficient at each time point, summing the unbalance coefficients at each time point to calculate an unbalance intensity of the distribution transformer, and adjusting the three-phase current values ​​at corresponding time points multiple times based on the maximum balance value and the minimum balance value until the unbalance intensity falls below an intensity threshold. Thus, multiple adjustments can be made to reduce the unbalance intensity to below the intensity threshold, thereby increasing adjustment flexibility.

[0016] Optionally, the method further includes calculating an unbalance coefficient at each time point, summing the unbalance coefficients at each time point to calculate an unbalance intensity of the distribution transformer, determining whether the unbalance intensity of the distribution transformer has decreased, and determining that the unbalance adjustment is effective when the unbalance intensity has decreased. Therefore, by determining whether the unbalance intensity of the distribution transformer has decreased, it is possible to determine whether the three-phase unbalance adjustment method is effective.

[0017] Optionally, the method further includes determining a preset number of cycles, and adjusting the three-phase current values ​​at corresponding time points multiple times according to the balanced maximum value and the balanced minimum value according to the preset number of cycles. Therefore, by setting the preset number of cycles, the adjustment method can be prevented from entering an infinite loop, thereby improving system reliability.

[0018] Optionally, the method further comprises: determining an adjustment period, accumulating adjustment amounts for each phase of the three-phase current within the adjustment period, and adjusting each phase of the three-phase current according to the adjustment amount. To this end, adjustment is performed based on the adjustment period input by the user, and reducing the frequency of adjustment can reduce the impact on the distribution transformer and the power grid.

[0019] The present invention also provides a device for regulating three-phase current imbalance of a distribution transformer, the device comprising:

[0020] An acquisition module obtains the time sequence three-phase current value and balance coefficient threshold of the distribution transformer;

[0021] The sorting module normalizes the three-phase current values ​​at each moment, sorts the current values ​​of each phase in the normalized three-phase current values, and records the position of each phase current value;

[0022] an adjustment module, calculating a maximum balance value and a minimum balance value at each time point according to the balance coefficient threshold, and adjusting the three-phase current value at the corresponding time point according to the maximum balance value and the minimum balance value so that the three-phase current value falls between the maximum balance value and the minimum balance value, wherein the sum of the three-phase current values ​​before and after the adjustment at each time point remains unchanged;

[0023] The restoration module restores the adjusted three-phase current values ​​according to the positions of the current values.

[0024] The present invention also provides an electronic device, comprising a processor, a memory, and instructions stored in the memory, wherein the instructions implement the above-mentioned method when executed by the processor.

[0025] The present invention also provides a computer-readable storage medium having computer instructions stored thereon. When the computer instructions are executed, the method described above is executed.

[0026] The present invention also provides a computer program product, comprising a computer program, which implements the above method when executed by a processor. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The following drawings are only intended to illustrate and explain the present invention, and do not limit the scope of the present invention.

[0028] FIG1 is a flow chart of a method for regulating three-phase current imbalance according to an embodiment of the present invention;

[0029] FIG2 shows the adjustment values ​​of three-phase current at various time points according to an embodiment of the present invention;

[0030] FIG3 is a schematic diagram of a daily cumulative regulation amount of three-phase current according to an embodiment of the present invention;

[0031] FIG4 is a schematic diagram of a daily cumulative adjustment amount of a smoothed three-phase current according to an embodiment of the present invention;

[0032] FIG5 is a schematic diagram of a quarterly cumulative regulation amount of three-phase current according to an embodiment of the present invention;

[0033] FIG6 is a schematic diagram of a three-phase current imbalance regulating device according to an embodiment of the present invention;

[0034] FIG7 is a schematic diagram of an electronic device according to an embodiment of the present invention.

[0035] DESCRIPTION OF REFERENCE NUMERALS 100 Method for adjusting three-phase current imbalance 110 - 140 Steps 600 Device for adjusting three-phase current imbalance 610 Acquisition module 620 Sorting module 630 Adjustment module 640 Restoration module 700 Electronic device 710 Processor 720 Memory DETAILED DESCRIPTION

[0036] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, specific embodiments of the present invention are now described with reference to the accompanying drawings.

[0037] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0038] As used in this application and the claims, unless the context clearly indicates otherwise, the words "a," "an," "an," and / or "the" are not intended to refer to the singular but may include the plural. Generally speaking, the terms "comprises" and "include" only indicate the inclusion of the steps and elements specifically identified, and these steps and elements do not constitute an exclusive list. A method or apparatus may also include other steps or elements.

[0039] The present invention provides a method for regulating three-phase current imbalance of a distribution transformer. FIG1 is a flow chart of a method 100 for regulating three-phase current imbalance according to an embodiment of the present invention. As shown in FIG1 , the method 100 includes:

[0040] Step 110, obtaining the time sequence three-phase current value and balance coefficient threshold of the distribution transformer;

[0041] A substation may include multiple distribution transformers, each of which may include multiple points. Each point may generate three-phase currents (ABC) during operation, with the ABC three-phase currents at different times constituting a time-sequential three-phase current value. The substation may include a central energy management system, where the three-phase current values ​​of different distribution transformers at different points and times may be recorded and stored in the central energy management system. The time-sequential three-phase current value of a specific distribution transformer may be obtained by reading the central energy management system. Alternatively, the distribution transformer may include an on-site energy management system, where the three-phase current values ​​of the distribution transformer at different points and times may be recorded and stored in the on-site energy management system. The time-sequential three-phase current value of the distribution transformer may be obtained by reading the on-site energy management system.

[0042] The balance coefficient threshold λ is an industry standard and is typically specified in the hardware parameters of a distribution transformer. By reading the hardware parameters of a distribution transformer, the balance coefficient threshold λ for that distribution transformer can be obtained. For example, the balance coefficient threshold λ for a distribution transformer may be 40%.

[0043] Table 1

[0044] Table 1 shows the time-series three-phase current value data for a certain point in a distribution transformer. The first column shows the current value for phase A, the second column shows the current value for phase B, and the third column shows the current value for phase C. Each row corresponds to a different moment, sampled every 15 minutes, with a sampling interval of 1 year, and a total of 35,136 rows of data. It is understood that for simplicity, Table 1 does not show all the data; only the three-phase current values ​​for the first three moments and the last three moments are shown. Table 1 does not show the units of current. It is understood that the units of current can be predefined in advance to reduce the amount of calculation. For example, the units of current can be predefined in advance as milliamperes or amperes.

[0045] Step 120 , normalizing the three-phase current values ​​at each moment, sorting the current values ​​of each phase in the normalized three-phase current values, and recording the position of each phase current value;

[0046] Normalizing the three-phase current values ​​at each moment can be done by dividing the three-phase current values ​​at each moment by the average of the three-phase current values ​​at that moment. After the three-phase current values ​​are normalized, the sum of the three-phase current values ​​is 3, thereby ensuring data standardization. The normalized three-phase current values ​​can be sorted in ascending or descending order. It is understood that the three-phase current values ​​at different moments are sorted according to the same rules, for example, all in ascending order or all in descending order, to facilitate subsequent processing.

[0047] The argsort function can be used to record the position of each phase current value. After subsequent processing and calculation, the calculation results can be restored to the order of the three phases ABC based on the position recorded by the argsort function. Taking the original data [88,22,99] as an example, 88 is the current value of phase A, 22 is the current value of phase B, and 99 is the current value of phase C. In computer programming language, it can be expressed as: arr array([88,22,99])

[0048] Use the sort function to sort the original data sort(arr), the sorting result is array([22,88,99]), use the argsort function to record the sorting position argsort(arr), 22 is the smallest, the corresponding sequence number is 0, 88 is the second sequence number 1, 99 is the largest sequence number 2, and the recorded result is array([1,0,2]), that is, the maximum value is the C phase current value, the middle value is the A phase current value, and the minimum value is the B phase current value. The position recording function can restore the processed three-phase current values ​​to the order of the three phases ABC.

[0049] Table 2

[0050] Table 2 shows the normalized data in Table 1. This is done by dividing each row of data by the sum of the row and then multiplying by 3. For example, the data in row 1 [0.14, 0.08, 0.14] in Table 1 is normalized to [0.38888889, 0.22222222, 0.38888889], and multiplying by 3 to [1.16666667, 0.66666667, 1.16666667].

[0051] Table 3

[0052] The data in Table 3 is the result of sorting the data in Table 2, and each row of data is sorted in ascending order.

[0053] Step 130: Calculate the maximum and minimum balanced values ​​at each time point based on the balance coefficient threshold, and adjust the three-phase current values ​​at the corresponding time point based on the maximum and minimum balanced values ​​so that the three-phase current values ​​fall between the maximum and minimum balanced values. The sum of the three-phase current values ​​before and after the adjustment remains unchanged.

[0054] The maximum balance value and the minimum balance value at each time point are calculated according to the balance coefficient threshold, which can be calculated by the following formula (1) and formula (2).

[0055] According to the definition of the balance coefficient threshold λ, the balanced three-phase current should satisfy the formula (1): abs((x i-μ) / μ)≤λ(1)

[0056] Where abs represents the absolute value, x i represents the current value of a phase at a certain moment, i.e. i = 0, 1, 2, corresponding to the three-phase currents A, B, and C respectively, and μ represents the average current value of each phase at a certain moment. Formula (1) can be rewritten as formula (2) after deformation as follows: (1-λ)μ≤x i ≤(1+λ)μ(2)

[0057] Indicates the current value x of a phase in the equilibrium state i The value range of needs to be between (1-λ)μ and (1+λ)μ, where (1-λ)μ is the minimum equilibrium value, which is defined as L, and (1+λ)μ is the maximum equilibrium value, which is defined as U, that is, x i The three-phase current must be between [L, U] to be in a balanced state, otherwise it is an unbalanced state. Taking the balance coefficient threshold λ as 40% as an example, assuming that the average value of each phase current is 1, then x i It needs to be in the range of [0.6,1.4] to be in equilibrium.

[0058] After determining the balance range, that is, the maximum balance value and the minimum balance value, the three-phase current value is adjusted so that the three-phase current value falls between the maximum balance value and the minimum balance value, while keeping the sum of the three-phase current values ​​before and after the adjustment at each time point unchanged, so that the three-phase current value reaches a balanced state.

[0059] In some embodiments, adjusting the three-phase current values ​​at corresponding time points according to the balanced maximum value and the balanced minimum value so that the three-phase current values ​​fall between the balanced maximum value and the balanced minimum value includes: determining whether the maximum current value among the three-phase current values ​​is greater than the balanced maximum value; if the maximum current value among the three-phase current values ​​is greater than the balanced maximum value, adjusting the three-phase current values ​​using a right operator; wherein adjusting the three-phase current values ​​using the right operator includes: calculating a difference between the maximum current value and the balanced maximum value, subtracting the difference from the maximum current value, and adding the difference to the minimum current value among the three-phase current values; and

[0060] Determine whether the minimum current value among the three-phase current values ​​is less than the minimum balanced value. If the minimum current value among the three-phase current values ​​is less than the minimum balanced value, use the left operator to adjust the three-phase current values. Wherein, using the left operator to adjust the three-phase current values ​​includes: calculating the difference between the minimum current value and the minimum balanced value, adding the difference to the minimum current value, and subtracting the difference from the maximum current value among the three-phase current values.

[0061] Specifically, we first define the distance function d(x,y)=max(xy,0), which represents the absolute distance between points x and y. The right operator can be expressed by formulas (3)-(5): x′2=x2-d(x2,U)(3) x1′=x1(4) x′0=x0+d(x2,U)(5)

[0062] Here, x2 represents the maximum current exceeding the equilibrium maximum, x′2 represents the adjusted x2, x1 and x1′ represent the intermediate current values ​​before and after adjustment, x0 represents the minimum current, x′0 represents the adjusted x0, and -d(x2, U) represents the distance between x2 and U. As can be seen, the right operator reduces the maximum current, leaves the intermediate value unchanged, and expands the minimum current. The reduction in the maximum current value and the expansion in the minimum current value are the same. By using the right operator, the maximum current exceeding the equilibrium maximum can be adjusted to within the equilibrium maximum.

[0063] The left operator can be expressed by formulas (6)-(8): x′2=x2-d(L,x0)(6) x′1=x1(7) x′0=x0+d(L,x0)(8)

[0064] Here, x0 represents the minimum current value below the equilibrium minimum, x′0 represents the adjusted x0, x1 and x1′ represent the intermediate current values ​​before and after adjustment, x2 represents the maximum current, x′2 represents the adjusted x2, and d(L,x0) represents the distance between L and x0. As can be seen, the left operator expands the minimum current value, leaves the intermediate value unchanged, and shrinks the maximum current value. The expansion of the minimum current value and the shrinkage of the maximum current value are the same. By using the left operator, the minimum current value below the equilibrium minimum can be adjusted to within the equilibrium minimum.

[0065] In some embodiments, the method further includes calculating an unbalance coefficient at each time point, summing the unbalance coefficients at each time point to calculate an unbalance intensity of the distribution transformer, and adjusting the three-phase current values ​​at the corresponding time points multiple times based on the maximum balance value and the minimum balance value until the unbalance intensity falls below an intensity threshold. Thus, by making multiple adjustments, the unbalance intensity can be reduced to below the intensity threshold, thereby increasing adjustment flexibility.

[0066] For example, for each row of time point data, an unbalance coefficient value k can be calculated by formula (9): i ,

[0067] Among them, x i It represents the current value of a certain phase at a certain moment. i=0, 1, 2 correspond to the three-phase currents A, B, and C respectively, and μ represents the average value.

[0068] abs(k i)>40% is unbalanced, and the phase imbalance p can be defined by formula (10): i :

[0069] For each row (i.e. time point) the imbalance degree p row , the phase imbalance p of this row i , i=0,1,2 add and average, and the travel imbalance degree p can be calculated row , that is, formula (11):

[0070] The imbalance intensity can be calculated by adding up the imbalance degrees of all rows, that is, formula (12):

[0071] After each adjustment, calculate the imbalance intensity P total , if the unbalanced strength P total Greater than the intensity threshold P threshold , then continue to adjust until the imbalance intensity P total Less than the intensity threshold P threshold .

[0072] In some embodiments, the method further includes: calculating the unbalance coefficient at each time point, summing the unbalance coefficients at each time point to calculate the unbalance strength of the distribution transformer, determining whether the unbalance strength of the distribution transformer has decreased, and determining that the unbalance adjustment is effective when the unbalance strength has decreased. The unbalance strength of the distribution transformer can be calculated according to formulas (9)-(12). After each adjustment, the unbalance strength of the distribution transformer is recalculated. If the unbalance strength of two adjacent times decreases, it indicates that the adjustment is effective. Otherwise, it indicates that the adjustment is invalid and the adjustment method needs to be changed. To this end, by determining whether the unbalance strength of the distribution transformer has decreased, it can be determined whether the three-phase unbalance adjustment method is effective.

[0073] In some embodiments, the method further includes determining a preset number of cycles, and adjusting the three-phase current values ​​at corresponding time points multiple times according to the maximum and minimum balanced values ​​according to the preset number of cycles. To avoid infinite loops, the number of cycles can be preset, for example, 100, and further adjustments can be stopped when 100 adjustments are made. Thus, by presetting the number of cycles, the adjustment method can be prevented from entering an infinite loop, thereby improving system reliability.

[0074] In some embodiments, the method further includes: determining an adjustment cycle, accumulating the adjustment amount of each phase of the three-phase current within the adjustment cycle, and adjusting each phase of the three-phase current according to the adjustment amount. Frequent adjustment can have a significant impact on the distribution transformer and the power grid, so reducing the frequency of adjustment can reduce the impact on the distribution transformer and the power grid. For example, adjustment can be performed on a monthly or quarterly basis, accumulating the adjustment amounts of the three phases A, B, and C for each month or quarter, and performing adjustment at the end of each month or quarter. To this end, adjustment is performed according to the adjustment cycle input by the user, and reducing the frequency of adjustment can reduce the impact on the distribution transformer and the power grid.

[0075] Figure 2 shows the regulation values ​​of a three-phase current at each time point according to an embodiment of the present invention, Figure 3 is a schematic diagram of the daily cumulative regulation value of a three-phase current according to an embodiment of the present invention, Figure 4 is a schematic diagram of the daily cumulative regulation value of a smoothed three-phase current according to an embodiment of the present invention, and Figure 5 is a schematic diagram of the quarterly cumulative regulation value of a three-phase current according to an embodiment of the present invention. Figure 2 shows the regulation values ​​of 35,136 data points ABC three phases, with different line styles corresponding to the corresponding ABC phases, where the regulation values ​​near the 5000th and 10,000th sampling points are larger, and the sum of the regulation values ​​of each phase is 0. Figure 3 shows the accumulated regulation values ​​of the sampling points on the same day in Figure 2, with different line styles corresponding to the corresponding ABC phases, and the sum of the regulation values ​​of each phase is 0. Figure 4 smoothes Figure 3. Figure 5 shows quarterly adjustments, i.e., adjustments are made once every quarter. At the end of the first quarter, phase A current remains unchanged, phase B current decreases by approximately 0.022, and phase C current increases by approximately 0.022. At the end of the second quarter, phase A and C currents increase by approximately 0.008, and phase B current decreases by approximately 0.016. At the end of the third quarter, phase B current remains unchanged, phase A current increases by approximately 0.018, and phase C current decreases by approximately 0.018. At the end of the fourth quarter, phase A current and phase C current increase by 0.002 and 0.005, respectively, and phase B current decreases by 0.007. Units are not shown in the above figures; the units can be A.

[0076] Step 140 : Restore the adjusted three-phase current values ​​according to the positions of the current values.

[0077] The argsort function records the positions of the current values, and the adjusted three-phase current values ​​are restored according to the positions of the current values ​​recorded by the argsort function, that is, each row is restored to the order of the three phases ABC.

[0078] Table 4

[0079] Table 4 shows the results after the data in Table 3 are adjusted and restored. It can be seen that the three-phase current values ​​at most time points fall between 0.6 and 1.4, that is, in a balanced state.

[0080] An embodiment of the present invention provides a method for regulating the three-phase current imbalance of a distribution transformer, wherein the maximum balance value and the minimum balance value are determined by a balance coefficient threshold, and the three-phase current value is adjusted so that the three-phase current value falls between the maximum balance value and the minimum balance value, thereby making the three-phase current in a balanced state, realizing automatic regulation of the three-phase current imbalance of the distribution transformer and improving the regulation efficiency.

[0081] The present invention further provides a device for regulating three-phase current imbalance of a distribution transformer. FIG6 is a schematic diagram of a device 600 for regulating three-phase current imbalance according to an embodiment of the present invention. As shown in FIG6 , the device 600 includes:

[0082] An acquisition module 610 acquires a time sequence three-phase current value and a balance coefficient threshold of a distribution transformer;

[0083] The sorting module 620 normalizes the three-phase current values ​​at each moment, sorts the current values ​​of each phase in the normalized three-phase current values, and records the position of each phase current value;

[0084] An adjustment module 630 calculates a maximum balance value and a minimum balance value at each time point based on the balance coefficient threshold value, and adjusts the three-phase current value at the corresponding time point based on the maximum balance value and the minimum balance value so that the three-phase current value falls between the maximum balance value and the minimum balance value. The sum of the three-phase current values ​​before and after the adjustment at each time point remains unchanged.

[0085] The restoration module 640 restores the adjusted three-phase current values ​​according to the positions of the current values.

[0086] The present invention further provides an electronic device 700. FIG7 is a schematic diagram of an electronic device 700 according to an embodiment of the present invention. As shown in FIG7 , the electronic device 700 includes a processor 710 and a memory 720. The memory 720 stores instructions, wherein the instructions, when executed by the processor 710, implement the method 100 described above.

[0087] The present invention further provides a computer-readable storage medium having computer instructions stored thereon. When the computer instructions are executed, the method 100 described above is executed.

[0088] The present invention further provides a computer program product, comprising a computer program, which implements the method 100 described above when the computer program is executed by a processor.

[0089] Some aspects of the methods and apparatus of the present invention may be performed entirely by hardware, entirely by software (including firmware, resident software, microcode, etc.), or by a combination of hardware and software. The above hardware or software may be referred to as "data blocks," "modules," "engines," "units," "components," or "systems." The processor may be one or more application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DAPDs), programmable logic devices (PLCs), field programmable gate arrays (FPGAs), processors, controllers, microcontrollers, microprocessors, or combinations thereof. In addition, various aspects of the present invention may be embodied as computer products in one or more computer-readable media, the product including computer-readable program code. For example, computer-readable media may include, but are not limited to, magnetic storage devices (e.g., hard disks, floppy disks, tapes, etc.), optical disks (e.g., compact disks (CDs), digital versatile disks (DVDs), etc.), smart cards, and flash memory devices (e.g., cards, sticks, key drives, etc.).

[0090] Flowcharts are used herein to illustrate the operations performed by the methods according to the embodiments of the present application. It should be understood that the preceding operations are not necessarily performed in exact order. Instead, the various steps may be performed in reverse order or simultaneously. Furthermore, other operations may be added to these processes, or one or more operations may be removed from these processes.

[0091] It should be understood that although this specification is described according to various embodiments, not every embodiment contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0092] The above description is only an illustrative embodiment of the present invention and is not intended to limit the scope of the present invention. Any equivalent changes, modifications and combinations made by those skilled in the art without departing from the concept and principle of the present invention shall fall within the scope of protection of the present invention.

[0093] Nouns and pronouns referring to persons in this patent application are not limited to a specific gender.

Claims

1. A method for adjusting the three-phase current imbalance of a distribution transformer, characterized in that, the method includes: obtaining the sequential three-phase current values and the balance coefficient threshold of the distribution transformer; normalizing the three-phase current values at each moment, sorting the phase current values in the normalized three-phase current values, and recording the positions of the phase current values; calculating the balance maximum value and the balance minimum value at each moment point according to the balance coefficient threshold, and adjusting the three-phase current values at the corresponding moment point according to the balance maximum value and the balance minimum value, so that the three-phase current values fall between the balance maximum value and the balance minimum value, wherein the sum of the three-phase current values before and after adjustment at each moment point remains unchanged; restoring the adjusted three-phase current values according to the positions of the current values.

2. The method according to claim 1, characterized in that, adjusting the three-phase current values at the corresponding moment point according to the balance maximum value and the balance minimum value so that the three-phase current values fall between the balance maximum value and the balance minimum value includes: determining whether the current maximum value in the three-phase current values is greater than the balance maximum value, if the current maximum value in the three-phase current values is greater than the balance maximum value, using a right operator to adjust the three-phase current values; wherein, using a right operator to adjust the three-phase current values includes: calculating the difference between the current maximum value and the balance maximum value, subtracting the difference from the current maximum value, and adding the difference to the current minimum value in the three-phase current values; and determining whether the current minimum value in the three-phase current values is less than the balance minimum value, if the current minimum value in the three-phase current values is less than the balance minimum value, using a left operator to adjust the three-phase current values; wherein, using a left operator to adjust the three-phase current values includes: calculating the difference between the current minimum value and the balance minimum value, adding the difference to the current minimum value, and subtracting the difference from the current maximum value in the three-phase current values.

3. The method according to claim 1 or 2, characterized in that, the method further includes: calculating the imbalance coefficient at each moment point, adding up the imbalance coefficients at each moment point to calculate the imbalance intensity of the distribution transformer, and adjusting the three-phase current values at the corresponding moment point according to the balance maximum value and the balance minimum value multiple times until the imbalance intensity is lower than the intensity threshold.

4. The method according to claim 1 or 2, characterized in that, the method further includes: calculating the imbalance coefficient at each moment point, adding up the imbalance coefficients at each moment point to calculate the imbalance intensity of the distribution transformer, determining whether the imbalance intensity of the distribution transformer is reduced, and determining that the imbalance adjustment is effective when the imbalance intensity is reduced.

5. The method according to claim 1 or 2, characterized in that, the method further includes: determining a preset number of cycles, and adjusting the three-phase current values at the corresponding moment point multiple times according to the preset number of cycles according to the balance maximum value and the balance minimum value.

6. The method according to claim 1 or 2, characterized in that, The method further includes: determining an adjustment period, accumulating the adjustment amounts of each phase in the three-phase current within the adjustment period, and adjusting each phase in the three-phase current according to the adjustment amounts.

7. An adjustment device for unbalanced three-phase current of a distribution transformer, characterized in that, the device includes: an acquisition module, which acquires the time-series three-phase current values and the balance coefficient threshold of the distribution transformer; a sorting module, which normalizes the three-phase current values at each moment, sorts the current values of each phase in the normalized three-phase current values, and records the positions of the current values of each phase; an adjustment module, which calculates the balance maximum value and the balance minimum value at each moment point according to the balance coefficient threshold, and adjusts the three-phase current values at the corresponding moment point according to the balance maximum value and the balance minimum value, so that the three-phase current values fall between the balance maximum value and the balance minimum value, wherein the sum of the three-phase current values before and after adjustment at each moment point remains unchanged; a restoration module, which restores the adjusted three-phase current values according to the positions of the current values.

8. An electronic device (700), comprising a processor (710), a memory (720), and instructions stored in the memory (720), wherein when the instructions are executed by the processor (710), the method (100) described in any one of claims 1-6 is implemented.

9. A computer-readable storage medium, on which computer instructions are stored, and the computer instructions execute the method (100) described in any one of claims 1-6 when running.

10. A computer program product, characterized in that, it includes a computer program, and when the computer program is executed by a processor, the method (100) described in any one of claims 1-6 is implemented.

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