Tap switching method and device of phase-shifting transformer and terminal equipment

Abstract

This invention relates to the field of power technology and provides a method, apparatus, and terminal equipment for tap switching of a phase-shifting transformer. The method includes: acquiring a target compensation voltage vector; determining at least one target tap switching combination based on the target compensation voltage vector; wherein the target tap switching combination includes the connection state of each stage of winding in the secondary winding of each phase; calculating the switching action amount when switching the current tap switching combination to each target tap switching combination; and performing tap switching on the phase-shifting transformer based on the target tap switching combination with the least switching action amount. This invention can determine the most suitable tap switching strategy for tap switching of the phase-shifting transformer.

Description

Technical Field

[0001] This invention belongs to the field of power technology, and in particular relates to a tap switching method, apparatus and terminal equipment for a phase-shifting transformer. Background Technology

[0002] In recent years, with the rapid growth of the scale of distributed photovoltaic and other new energy sources connected to the power grid, severe challenges have been brought to the distribution, consumption, and power flow optimization control of new energy power. Flexible AC transmission devices based on power electronics technology (such as power flow controllers) can effectively improve the transmission capacity of the transmission network and achieve optimization of the system power flow distribution on a temporal scale and balance on a spatial scale.

[0003] Sen transformers (STs) utilize transformer and on-load tap changer switching technology to achieve low-cost power flow control. STs inject a series voltage of a certain amplitude and angle into the line, thereby changing the voltage difference between the sending and receiving ends and controlling the power flow through the transmission line. STs can independently control both active and reactive power, and have lower installation, operation, and maintenance costs. However, due to the discreteness of on-load tap changers, STs can only adjust voltage at a limited number of operating points, resulting in decreased accuracy and dynamic performance. To increase the density of compensation points within the ST's operating range, a new structure is proposed: using tap changer windings with asymmetrical voltage, and bidirectionally connected to the main winding. This structure maximizes the number of compensation points within the ST's compensation range, reduces the number of taps, improves the ST's flexibility and adjustment accuracy, and is more cost-effective. However, the synthesis method of the ST's operating point using asymmetrical voltage has degrees of freedom; that is, the same operating point may correspond to different tap positions and winding states. Determining the most suitable tap switching strategy is a problem that needs to be solved. Summary of the Invention

[0004] In view of this, embodiments of the present invention provide a tap switching method, apparatus and terminal equipment for a phase-shifting transformer, so as to determine the most suitable tap switching strategy for tap switching of the phase-shifting transformer.

[0005] The first aspect of the present invention provides a tap switching method for a phase-shifting transformer. The phase-shifting transformer consists of three single-phase four-winding transformers. The primary three-phase windings are connected in a star configuration. The three secondary windings of each phase are respectively connected in series in different three-phase lines, and each secondary winding contains at least two winding stages.

[0006] The method includes:

[0007] Obtain the target compensation voltage vector;

[0008] At least one target tap switching combination is determined based on the target compensation voltage vector; wherein, the target tap switching combination includes the connection state of each stage of winding in the secondary winding of each phase in the compensation unit;

[0009] Calculate the switching action amount when switching the current tap switching combination to each target tap switching combination;

[0010] The phase-shifting transformer is tapped based on the target tap switching combination that minimizes the amount of switching action.

[0011] Optionally, at least one target tap switching combination is determined based on the target compensation voltage vector, including:

[0012] Find the compensation voltage vector that is closest to the target compensation voltage vector from the pre-established tap switching combination table, and find the tap switching combination corresponding to the closest compensation voltage vector to obtain at least one target tap switching combination.

[0013] The tap switching combination table contains all the tap switching combinations of the phase-shifting transformer, as well as the compensation voltage vector corresponding to each tap switching combination.

[0014] Optionally, the connection status of each winding stage includes forward connection, reverse connection, and no connection; the calculation of the switching action quantity when switching the current tap switching combination to a certain target tap switching combination includes:

[0015] The sum of the changes in the connection state of each level of winding in all secondary windings is calculated when the current tap switching combination is switched to a certain target tap switching combination, and the switching action quantity is obtained.

[0016] Wherein, when the connection state of a certain winding remains unchanged, the change in connection state is 0; when the connection state of a certain winding changes from forward connection to reverse connection, or from reverse connection to forward connection, the change in connection state is x; when the connection state of a certain winding changes from forward connection or reverse connection to no connection, or from no connection to forward connection or reverse connection, the change in connection state is y; and x>y>0.

[0017] Optionally, the phase-shifting transformer can be tapped based on the target tap switching combination that minimizes the amount of switching action, including:

[0018] Switch the connection status of each winding in the current tap switching combination to the same level as the connection status of each winding in the target tap switching combination with the least amount of switching action.

[0019] Optionally, the tap switching method for the phase-shifting transformer also includes:

[0020] If there is more than one target tap switching combination with the least amount of switching action, then calculate the number of windings with a corresponding change in connection state of x in each target tap switching combination, and denote it as z;

[0021] Select the target tap switching combination with the smallest corresponding z value to perform tap switching on the phase-shifting transformer.

[0022] Optionally, the phase-shifting transformer is a Sen transformer.

[0023] The second aspect of the present invention provides a tap switching device for a phase-shifting transformer. The phase-shifting transformer consists of three single-phase four-winding transformers. The primary three-phase windings are connected in a star configuration. The three secondary windings of each phase are respectively connected in series in different three-phase lines, and each secondary winding contains at least two winding stages.

[0024] The device includes:

[0025] The acquisition module is used to acquire the target compensation voltage vector;

[0026] The determination module is used to determine at least one target tap switching combination based on the target compensation voltage vector; wherein, the target tap switching combination includes the connection state of each stage of winding in each secondary winding;

[0027] The calculation module is used to calculate the switching action amount when switching the current tap switching combination to each target tap switching combination;

[0028] The control module is used to switch the taps of the phase-shifting transformer based on the target tap switching combination that minimizes the amount of switching action.

[0029] Optionally, the connection status of each winding includes forward connection, reverse connection, and no connection;

[0030] The calculation module is specifically used for:

[0031] The sum of the changes in the connection state of each level of winding in all phase secondary windings is calculated when the current tap switching combination is switched to a certain target tap switching combination, and the switching action quantity is obtained.

[0032] Wherein, when the connection state of a certain winding remains unchanged, the change in connection state is 0; when the connection state of a certain winding changes from forward connection to reverse connection, or from reverse connection to forward connection, the change in connection state is x; when the connection state of a certain winding changes from forward connection or reverse connection to no connection, or from no connection to forward connection or reverse connection, the change in connection state is y; and x>y>0.

[0033] A third aspect of the present invention provides a terminal device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the steps of the phase-shifting transformer tap switching method as described in the first aspect above.

[0034] A fourth aspect of the present invention provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps of the tap switching method for a phase-shifting transformer as described in the first aspect above.

[0035] The beneficial effects of the embodiments of the present invention compared with the prior art are as follows:

[0036] In this embodiment of the invention, at least one target tap switching combination that is closest to the target compensation voltage vector is determined based on the target compensation voltage vector. Then, the switching action amount when switching the current tap switching combination to each target tap switching combination is calculated. Based on the target tap switching combination with the fewest switching action amounts, the phase-shifting transformer is tap-switched. The tap switching combination that is closest to the target compensation voltage vector and has the fewest switching times is selected, which effectively improves the response speed of the phase-shifting transformer, reduces the transient process of switching, and enhances the stability of the power flow control of the phase-shifting transformer. Attached Figure Description

[0037] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0038] Figure 1 This is a schematic diagram of the structure of the Sen transformer provided in an embodiment of the present invention;

[0039] Figure 2 This is a schematic flowchart of the tap switching method for a phase-shifting transformer provided in an embodiment of the present invention;

[0040] Figure 3 This is a schematic diagram of the structure of the 220kV double-circuit system provided in an embodiment of the present invention;

[0041] Figure 4 This is a schematic diagram of the tap switching structure of the phase-shifting transformer provided in an embodiment of the present invention;

[0042] Figure 5 This is a schematic diagram of a terminal device provided in an embodiment of the present invention. Detailed Implementation

[0043] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of the invention. However, those skilled in the art will understand that the invention can be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods are omitted so as not to obscure the description of the invention with unnecessary detail.

[0044] To illustrate the technical solution described in this invention, specific embodiments are described below.

[0045] This invention provides a tap switching method for a phase-shifting transformer. The phase-shifting transformer consists of three single-phase four-winding transformers. The primary three-phase windings are connected in a star configuration, and the three secondary windings of each phase are connected in series in different three-phase lines. Each secondary winding contains at least two winding stages. As a preferred implementation, the phase-shifting transformer can be a Sen transformer. For example, the topology of a certain secondary winding and switch of ST is as follows: Figure 1 As shown, ST compensation voltage U se2 Based on three-phase voltage synthesis, assume the coordinates of the ST compensation point before the power flow command change are U0[a0, b0, c0]. The ST stage number is 2, the stage voltage ratio is 4:1, and the magnitude of the stage voltage is 0.4U. se2 The other level is 0.1U. se2 By switching the direction of each winding's connection to the circuit using a control switch, the polarity of the stage voltage can be changed. Figure 3 Taking the primary winding as an example, in steady state, if the winding is not connected to the line, switches 2 and 4 are turned on and the other switches are turned off; if the primary winding is connected to the positive winding, switches 1, 9 and 4 are turned on and the other switches are turned off; if the primary winding is connected to the negative winding, switches 2, 3 and 9 are turned on and the other switches are turned off. Thus, the two windings can be combined to produce different secondary winding voltages.

[0046] To accurately regulate system power flow, the voltage provided by the ST (Stage Controller) should be as close as possible to the target compensation voltage. The ST uses a secondary winding with an asymmetrical voltage stage. The asymmetrical hexagonal decomposition algorithm can determine the operating point with the smallest distance error from the target compensation point. However, unlike traditional STs, the ST using an H-bridge asymmetrical voltage stage has a degree of freedom in its operating point synthesis method; that is, the same operating point may correspond to different tap positions and winding states, and the number of switching operations will also differ. Therefore, this invention provides a tap selection strategy for a power flow controller ST, which enables the control system to accurately select the tap position closest to the target voltage and with the fewest switching operations after a change in power flow command. See [link to relevant documentation]. Figure 2 As shown, the method includes the following steps:

[0047] Step S101: Obtain the target compensation voltage vector.

[0048] In this embodiment of the invention, the target compensation voltage vector is the vector composite of the three-phase voltages to be compensated.

[0049] Step S102: Determine at least one target tap switching combination based on the target compensation voltage vector; wherein, the target tap switching combination includes the connection state of each level of winding in each secondary winding.

[0050] As one possible implementation, step S102, determining at least one target tap switching combination based on the target compensation voltage vector, can be detailed as follows:

[0051] The system finds the compensation voltage vector that is closest to the target compensation voltage vector from a pre-established tap switching combination table, and finds the tap switching combination corresponding to the closest compensation voltage vector to obtain at least one target tap switching combination; wherein, the tap switching combination table contains all tap switching combinations of the phase-shifting transformer, and the compensation voltage vector corresponding to each tap switching combination.

[0052] In this embodiment of the invention, the relationship between the compensation voltage provided by any secondary winding and the winding state can be expressed as:

[0053] U = m·0.1U se2 +n·0.4U se2

[0054] In the formula, m and n represent the states of the two winding stages, and their values ​​can be 1, 0, and -1. 0 indicates that the winding is not connected, 1 indicates that the positive winding stage is connected, and -1 indicates that the negative winding stage is connected.

[0055] Therefore, the winding states corresponding to the three-phase coordinates of U0[a0, b0, c0] are Ta1, Ta2, Tb1, Tb2, and Tc1, Tc2, respectively. After the power flow command changes, the operating point U closest to the target compensation point can be obtained using the asymmetric hexagonal algorithm. n [a n b n c n And find U n Voltage vector corresponding to the point:

[0056]

[0057] In this embodiment, for convenience, all voltage vectors that ST can compensate for are calculated and stored. After obtaining the target compensation voltage vector, the closest compensation voltage vector is determined directly by looking up a table, and then the vector with U is found. n By knowing all the same voltage vectors, we can determine U. n All corresponding tap-and-slice combinations.

[0058] Step S103: Calculate the switching action amount when switching the current tap switching combination to each target tap switching combination.

[0059] As one possible implementation, in step S103, the connection status of each winding stage includes forward connection, reverse connection, and no connection; the calculation of the switching action quantity when switching the current tap switching combination to a certain target tap switching combination can be detailed as follows:

[0060] The switching action quantity is obtained by calculating the sum of the changes in the connection state of each level of winding in all secondary windings of the three phases when switching the current tap switching combination to a certain target tap switching combination. Among them, the change in connection state is 0 when the connection state of a certain level of winding remains unchanged; the change in connection state is x when the connection state of a certain level of winding changes from forward connection to reverse connection or from reverse connection to forward connection; the change in connection state is y when the connection state of a certain level of winding changes from forward connection or reverse connection to no connection or from no connection to forward connection or reverse connection; and x>y>0.

[0061] In this embodiment, for example, the difference in the winding state of each stage corresponding to the three-phase coordinates of different tap switching combinations before and after the change in power flow command can be calculated, denoted by δTa1, δTa2, δTb1, δTb2, δTc1, and δTc2. The synthesis method with the smallest sum of absolute difference values ​​(i.e., the change in connection state) is selected, and its coordinates are used as the tap position with the fewest switching operations. The switching operation amount c can be expressed as...

[0062] c=min{|δTa1 i |+|δTa2 i |+|δTb1 i |+|δTb2 i |+|δTc1 i |+|δTc2 i}

[0063] Ideally, the value of x can be set to 2 and the value of y to 1. That is, when the winding changes between not connected and connected, the switch only operates once, and when it changes between forward connection and reverse connection, the switch needs to operate twice.

[0064] Step S104: Tap switching is performed on the phase-shifting transformer based on the target tap switching combination with the least amount of switching action.

[0065] As one possible implementation, step S104, which involves tap switching of the phase-shifting transformer based on the target tap switching combination with the least amount of switching action, can be described in detail as follows:

[0066] Switch the connection status of each winding in the current tap switching combination to the same level as the connection status of each winding in the target tap switching combination with the least amount of switching action.

[0067] In this embodiment, taking the value of x as 2 and the value of y as 1 as an example, there are 5 possible values ​​for adjusting the difference between the states of the windings before and after the adjustment: -1, 0, 1, 2, -2. The corresponding switching sequence is shown in Table 1.

[0068] Table 1 Winding switch operation sequence

[0069]

[0070]

[0071] As can be seen, the embodiments of the present invention determine at least one target tap switching combination based on the target compensation voltage vector, then calculate the switching action amount when switching the current tap switching combination to each target tap switching combination, and perform tap switching on the phase-shifting transformer based on the target tap switching combination with the least switching action amount. This can select the tap switching combination that is closest to the target compensation voltage vector and has the fewest switching times, effectively improving the response speed of the phase-shifting transformer, reducing the transient process of switching, and enhancing the stability of the phase-shifting transformer control power flow.

[0072] As one possible implementation method, the tap switching method for phase-shifting transformers also includes:

[0073] If there is more than one target tap switching combination with the least amount of switching action, then calculate the number of windings with a corresponding change in connection state of x in each target tap switching combination, and denote it as z;

[0074] Select the target tap switching combination with the smallest corresponding z value to perform tap switching on the phase-shifting transformer.

[0075] In this embodiment, selecting the target tap switching combination with the smallest z-value to perform tap switching on the phase-shifting transformer can reduce the number of windings that need to be switched twice, further improve the response speed of the phase-shifting transformer, reduce the transient process of switching, and enhance the stability of the power flow control of the phase-shifting transformer.

[0076] In one embodiment, a selection such as Figure 3 The 220kV double-circuit system shown is used to verify the effectiveness of the proposed method by adding ST to line 2 to regulate the power flow.

[0077] ST Ru Figure 1 As shown, there are 2 stages and the stage voltage ratio is 4:1. By switching the direction of each stage winding connected to the line by the control switch, the polarity of the stage voltage can be changed.

[0078] During the previous power flow adjustment, the coordinates of the ST compensation point were U0[3, -3, 0]. Based on the relationship between the coordinates (i.e., the magnitude of the compensation voltage for each phase) and the winding states, the winding states corresponding to the three-phase coordinates of U0 are Ta1 = 1, Ta2 = -1, Tb1 = -1, Tb2 = 1, Tc1 = 0, Tc2 = 0. After the power flow command changes, the operating point Un[-3, -5, 3] closest to the target compensation point can be obtained by looking up a table or using the asymmetric hexagonal algorithm, and the voltage vector corresponding to point Un can be calculated.

[0079] U n =-2+j6.928

[0080] The ST with a 4:1 asymmetrical voltage level has an equivalent stage number of 4. There are 729 possible voltage vectors that can be synthesized from the three-phase equivalent stage voltages. Grouping identical voltage vectors together, we can obtain a total of 319 operating points for the ST. Each operating point may correspond to multiple tap switching combinations. Using a lookup table, we can find the corresponding U... n The same voltage vectors are U1[-3, -5, 3] and U2[-1, -3, 5]. Based on the tap switching combinations corresponding to the voltage vectors, the difference in the state of each winding stage before and after the change in power flow command is calculated for different tap switching combinations, denoted by δTa1, δTa2, δTb1, δTb2, δTc1, and δTc2. The sum of the absolute values ​​of the differences, c, is also calculated. Different operating points and corresponding tap switching combinations and switching action quantities are shown in Table 2.

[0081] Table 2 Operating points and corresponding tap switching combinations

[0082]

[0083] It can be seen that the amount of switching action is significantly reduced during adjustment in Synthesis Method 2. This tap selection strategy can effectively select the tap switching combination with the fewest switching operations, and the effect is more obvious when there are more secondary winding stages. After selecting the tap switching combination with the fewest switching operations, the initial winding state value and the difference between the winding state before and after adjustment can be obtained according to Table 2. Thus, the switching action sequence on each winding stage can be obtained according to Table 1, and the tap switching combination can be switched accordingly.

[0084] The ST tap selection strategy proposed in this invention enables the control system to accurately select the tap switching combination that is closest to the target voltage and has the fewest switching operations after a change in power flow command. This effectively improves the ST response speed, reduces the transient process of switching, reduces switch damage, and enhances the stability of ST control power flow. Furthermore, this method is applicable to any power system scenario and has strong versatility.

[0085] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0086] This invention provides a tap switching device for a phase-shifting transformer. The phase-shifting transformer consists of three single-phase four-winding transformers. The primary three-phase windings are connected in a star configuration, and the three secondary windings of each phase are connected in series in different three-phase lines. Each secondary winding contains at least two winding stages.

[0087] See Figure 4 As shown, the device 40 includes:

[0088] The acquisition module 41 is used to acquire the target compensation voltage vector.

[0089] The determining module 42 is used to determine at least one target tap switching combination based on the target compensation voltage vector; wherein, the target tap switching combination includes the connection state of each level of winding in each secondary winding.

[0090] The calculation module 43 is used to calculate the switching action amount when switching the current tap switching combination to each target tap switching combination.

[0091] Control module 44 is used to switch the taps of the phase-shifting transformer based on the target tap switching combination with the least amount of switching action.

[0092] As one possible implementation, module 42 is specifically used for:

[0093] The system finds the compensation voltage vector that is closest to the target compensation voltage vector from a pre-established tap switching combination table, and finds the tap switching combination corresponding to the closest compensation voltage vector to obtain at least one target tap switching combination; wherein, the tap switching combination table contains all tap switching combinations of the phase-shifting transformer, and the compensation voltage vector corresponding to each tap switching combination.

[0094] As one possible implementation, the connection status of each winding stage includes forward connection, reverse connection, and no connection. The calculation module 43 is specifically used for:

[0095] The sum of the changes in the connection state of each level of all secondary windings in the three phases is calculated when the current tap switching combination is switched to a certain target tap switching combination, and the switching action quantity is obtained.

[0096] Wherein, when the connection state of a certain winding remains unchanged, the change in connection state is 0; when the connection state of a certain winding changes from forward connection to reverse connection, or from reverse connection to forward connection, the change in connection state is x; when the connection state of a certain winding changes from forward connection or reverse connection to no connection, or from no connection to forward connection or reverse connection, the change in connection state is y; and x>y>0.

[0097] As one possible implementation, control module 44 is specifically used for:

[0098] Switch the connection status of each winding in the current tap switching combination to the same level as the connection status of each winding in the target tap switching combination with the least amount of switching action.

[0099] As one possible implementation, control module 44 is also used for:

[0100] If there is more than one target tap switching combination with the least amount of switching action, then calculate the number of windings with a corresponding change in connection state of x in each target tap switching combination, and denote it as z;

[0101] Select the target tap switching combination with the smallest corresponding z value to perform tap switching on the phase-shifting transformer.

[0102] As one possible implementation, the phase-shifting transformer is a Sen transformer.

[0103] Figure 5 This is a schematic diagram of a terminal device 50 provided in an embodiment of the present invention. For example... Figure 5 As shown, the terminal device 50 of this embodiment includes: a processor 51, a memory 52, and a computer program 53 stored in the memory 52 and executable on the processor 51, such as a tap switching program for a phase-shifting transformer. When the processor 51 executes the computer program 53, it implements the steps in the various tap switching method embodiments of the phase-shifting transformer described above, for example... Figure 1 The steps S101 to S104 are shown. Alternatively, when the processor 51 executes the computer program 53, it implements the functions of each module in the above-described device embodiments, for example... Figure 4 The functions of modules 41 to 44 are shown.

[0104] For example, computer program 53 can be divided into one or more modules / units, one or more of which are stored in memory 52 and executed by processor 51 to complete the present invention. One or more modules / units can be a series of computer program instruction segments capable of performing specific functions, which describe the execution process of computer program 53 in terminal device 50. For example, computer program 53 can be divided into acquisition module 41, determination module 42, calculation module 43, and control module 44 (a module in a virtual device), with the specific functions of each module as follows:

[0105] The acquisition module 41 is used to acquire the target compensation voltage vector.

[0106] The determining module 42 is used to determine at least one target tap switching combination based on the target compensation voltage vector; wherein, the target tap switching combination includes the connection state of each level of winding in each secondary winding.

[0107] The calculation module 43 is used to calculate the switching action amount when switching the current tap switching combination to each target tap switching combination.

[0108] Control module 44 is used to switch the taps of the phase-shifting transformer based on the target tap switching combination with the least amount of switching action.

[0109] Terminal device 50 can be a computing device such as a desktop computer, laptop, handheld computer, or cloud server. Terminal device 50 may include, but is not limited to, a processor 51 and a memory 52. ​​Those skilled in the art will understand that... Figure 5 This is merely an example of terminal device 50 and does not constitute a limitation on terminal device 50. It may include more or fewer components than shown, or combine certain components, or different components. For example, terminal device 50 may also include input / output devices, network access devices, buses, etc.

[0110] The processor 51 may be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor.

[0111] The memory 52 can be an internal storage unit of the terminal device 50, such as a hard disk or RAM of the terminal device 50. The memory 52 can also be an external storage device of the terminal device 50, such as a plug-in hard disk, Smart Media Card (SMC), Secure Digital (SD) card, or Flash Card equipped on the terminal device 50. Furthermore, the memory 52 can include both internal and external storage units of the terminal device 50. The memory 52 is used to store computer programs and other programs and data required by the terminal device 50. The memory 52 can also be used to temporarily store data that has been output or will be output.

[0112] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is merely an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. Furthermore, the specific names of the functional units and modules are only for easy differentiation and are not intended to limit the scope of protection of this application. The specific working process of the units and modules in the above system can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0113] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0114] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0115] In the embodiments provided by this invention, it should be understood that the disclosed apparatus / terminal devices and methods can be implemented in other ways. For example, the apparatus / terminal device embodiments described above are merely illustrative. For instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0116] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0117] Furthermore, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0118] If an integrated module / unit is implemented as 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, all or part of the processes in the methods of the above embodiments of the present invention can also be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable medium can include: any entity or device capable of carrying computer program code, recording media, USB flash drives, portable hard drives, magnetic disks, optical disks, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signals, telecommunication signals, and software distribution media, etc. It should be noted that the content included in the computer-readable medium can be appropriately added or removed according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, the computer-readable medium does not include electrical carrier signals and telecommunication signals.

[0119] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A tap switching method for a phase-shifting transformer, characterized in that, The phase-shifting transformer is an asymmetrical voltage Sen transformer. The phase-shifting transformer consists of three single-phase four-winding transformers. The primary three-phase windings are connected in a star configuration. The three secondary windings of each phase are connected in series in different three-phase lines. Each secondary winding contains at least two winding stages. The method includes: Obtain the target compensation voltage vector; Based on the target compensation voltage vector, at least one target tap switching combination corresponding to the target compensation voltage vector is determined; wherein, the target tap switching combination includes the connection state of each level of winding in each secondary winding; Calculate the switching action amount when switching the current tap switching combination to each target tap switching combination; Tap switching of the phase-shifting transformer is performed based on the target tap switching combination that minimizes the amount of switching action. The connection status of each winding stage includes forward connection, reverse connection, and no connection; the calculation of the switching action when switching the current tap switching combination to a certain target tap switching combination includes: The switching action quantity is obtained by calculating the sum of the changes in the connection state of each level of winding in all secondary windings when switching the current tap switching combination to a certain target tap switching combination; wherein, when the connection state of a certain level winding remains unchanged, the change in connection state is 0; when the connection state of a certain level winding changes from forward connection to reverse connection, or from reverse connection to forward connection, the change in connection state is x; when the connection state of a certain level winding changes from forward connection or reverse connection to no connection, or from no connection to forward connection or reverse connection, the change in connection state is y; and x>y>0. The method further includes: If there is more than one target tap switching combination with the least amount of switching action, then calculate the number of windings with a corresponding change in connection state of x in each target tap switching combination, and denote it as z; Select the target tap switching combination with the smallest corresponding z value to perform tap switching on the phase-shifting transformer.

2. The tap switching method for a phase-shifting transformer as described in claim 1, characterized in that, Determining at least one target tap switching combination based on the target compensation voltage vector includes: Find the compensation voltage vector that is closest to the target compensation voltage vector from the pre-established tap switching combination table, and find the tap switching combination corresponding to the closest compensation voltage vector to obtain at least one target tap switching combination. The tap switching combination table contains all the tap switching combinations of the phase-shifting transformer, as well as the compensation voltage vector corresponding to each tap switching combination.

3. The tap switching method for a phase-shifting transformer as described in claim 1, characterized in that, Tap switching of the phase-shifting transformer is performed based on the target tap switching combination with the minimum switching operation amount, including: Switch the connection status of each winding in the current tap switching combination to the same level as the connection status of each winding in the target tap switching combination with the least amount of switching action.

4. The tap switching method for a phase-shifting transformer as described in any one of claims 1-3, characterized in that, The phase-shifting transformer is a Sen transformer.

5. A tap switching device for a phase-shifting transformer, characterized in that, The phase-shifting transformer is an asymmetrical voltage Sen transformer. The phase-shifting transformer consists of three single-phase four-winding transformers. The primary three-phase windings are connected in a star configuration. The three secondary windings of each phase are connected in series in different three-phase lines. Each secondary winding contains at least two winding stages. The device includes: The acquisition module is used to acquire the target compensation voltage vector; The determining module is used to determine at least one target tap switching combination corresponding to the target compensation voltage vector based on the target compensation voltage vector; wherein, the target tap switching combination includes the connection state of each stage of winding in each secondary winding; The calculation module is used to calculate the switching action amount when switching the current tap switching combination to each target tap switching combination; The control module is used to switch the taps of the phase-shifting transformer based on the target tap switching combination with the least amount of switching action. The connection status of each winding stage includes forward connection, reverse connection, and no connection; the calculation of the switching action when switching the current tap switching combination to a certain target tap switching combination includes: The switching action quantity is obtained by calculating the sum of the changes in the connection state of each level of winding in all secondary windings when switching the current tap switching combination to a certain target tap switching combination; wherein, when the connection state of a certain level winding remains unchanged, the change in connection state is 0; when the connection state of a certain level winding changes from forward connection to reverse connection, or from reverse connection to forward connection, the change in connection state is x; when the connection state of a certain level winding changes from forward connection or reverse connection to no connection, or from no connection to forward connection or reverse connection, the change in connection state is y; and x>y>0. If there is more than one target tap switching combination with the least amount of switching action, then calculate the number of windings with a corresponding change in connection state of x in each target tap switching combination, and denote it as z; Select the target tap switching combination with the smallest corresponding z value to perform tap switching on the phase-shifting transformer.

6. A terminal device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the method as described in any one of claims 1 to 4.

7. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by a processor, it implements the steps of the method as described in any one of claims 1 to 4.

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