Substation standby power automatic putting-in method, device and system

Abstract

The application relates to a substation backup power automatic input method, device and system. The method is applied to a substation comprising a first main transformer, a second main transformer and a third main transformer; the low-voltage side of the first main transformer is connected with a first bus; the low-voltage sides of the second main transformer are respectively connected with a second bus and a third bus; the low-voltage side of the third main transformer is connected with a fourth bus; the first bus and the second bus are connected through a first sectional switch; the third bus and the fourth bus are connected through a second sectional switch; the method comprises the following steps: acquiring rated parameters, operating parameters and a current operating mode of the substation; adopting a preset model to process the rated parameters and the operating parameters based on the current operating mode, and determining the most economical operating mode of the substation; the preset model takes the minimization of total transformer loss as an objective; and if the current operating mode is not the most economical operating mode, switching is carried out based on the most economical operating mode. The method can save energy.

Description

Technical Field

[0001] This application relates to the field of automatic transfer switch technology, and in particular to a method, apparatus and system for automatically transferring backup power to a substation. Background Technology

[0002] Automatic transfer switch (ATS) is short for automatic switching device for backup power supplies. With the development of power systems, the role of ATS is becoming increasingly important. ATS can quickly restore bus voltage, improve the power supply capacity during normal grid operation, and enhance the reliability of power supply.

[0003] With the development of automatic transfer switch (ATS) technology, ATS is mainly used in medium and low voltage power distribution systems of 110kV and below. The 10kV low-voltage side of the main transformer in the substation is usually operated in a split manner. If the 10kV low-voltage busbar of the substation loses voltage, the automatic transfer switch can automatically and quickly put the backup power supply into operation to ensure the continuous operation of the electrical equipment. At present, the operating mode of the transformer before the busbar loses voltage is set by each power supply department and operated manually. The following two methods are usually adopted: (1) Put all transformers into operation without considering the economic operation of the transformers; (2) Select the number of transformers to be put into operation according to the no-load loss, load loss and load current of the transformers.

[0004] However, current automatic backup power supply methods or traditional methods used in substations have problems such as energy waste. Summary of the Invention

[0005] Therefore, it is necessary to provide a method, device, system, computer-readable storage medium, and computer program product for automatically switching on backup power to substations, which can save energy, in response to the above-mentioned technical problems.

[0006] In a first aspect, this application provides a method for automatically switching on backup power in a substation. The method is applied to a substation including a first main transformer, a second main transformer, and a third main transformer. The high-voltage sides of the first, second, and third main transformers are all connected to the power transmission network; the low-voltage side of the first main transformer is connected to a first busbar; the low-voltage side of the second main transformer is connected to both the second and third busbars; the low-voltage side of the third main transformer is connected to a fourth busbar; the first and second busbars are connected via a first sectionalizing switch; the third and fourth busbars are connected via a second sectionalizing switch; the method includes:

[0007] Obtain the substation's rated parameters, operating parameters, and current operating mode;

[0008] A preset model is used to process rated parameters and operating parameters based on the current operating mode to determine the most economical operating mode of the substation; the preset model aims to minimize the total transformer loss.

[0009] If the current operating mode is not the most economical operating mode, the first main transformer, the second main transformer, the third main transformer, the first sectionalizing switch and the second sectionalizing switch shall be switched on and off respectively based on the most economical operating mode.

[0010] In one embodiment, the step of determining the most economical operating mode of a substation by using a preset model to process rated parameters and operating parameters based on the current operating mode includes:

[0011] Based on the current operating mode, the rated parameters and operating parameters are processed to obtain the transformer loss under the current mode; the rated parameters and operating parameters are then converted to obtain the expected transformer loss after switching.

[0012] The substation's operating parameters are processed using a pre-set model to obtain the current transformer loss and the expected transformer loss after switching. The rated parameters include the rated parameters of the first main transformer, the second main transformer, and the third main transformer. The operating parameters include the current current of the first sectionalizing switch and the current current of the second sectionalizing switch.

[0013] Based on the current operating mode, select the appropriate criteria, compare the transformer loss under the current mode with the expected transformer loss after switching, and obtain the criterion comparison results.

[0014] In one embodiment, the method further includes:

[0015] Based on the comparison results of the criteria, the number of main transformers that need to be put into operation among the first main transformer, the second main transformer, and the third main transformer is determined.

[0016] If the number of main transformers to be put into operation is 3, then the first operating mode is determined as the most economical operating mode; the first operating mode includes the first main transformer, the second main transformer and the third main transformer being put into operation, and the first sectionalizing switch and the second sectionalizing switch being in the open state.

[0017] If the number of main transformers to be put into operation is 2, then the second operating mode is determined as the most economical operating mode. The second operating mode includes the first main transformer not being put into operation, the second and third main transformers being put into operation, the first sectionalizing switch being closed, and the second sectionalizing switch being open.

[0018] If the number of main transformers to be put into operation is 1, then the third operating mode is determined as the most economical operating mode. The third operating mode includes the following: neither the first main transformer nor the third main transformer is put into operation, the second main transformer is put into operation, and both the first sectionalizing switch and the second sectionalizing switch are in the closed state.

[0019] In one embodiment, the substation's operation mode categories include a first operation mode, a second operation mode, and a third operation mode; wherein, the number of main transformers put into operation in the first operation mode is 3; the number of main transformers put into operation in the second operation mode is 2; and the number of main transformers put into operation in the third operation mode is 1.

[0020] The steps of selecting the appropriate criterion based on the current operating mode, comparing the transformer loss under the current mode with the expected transformer loss after switching, and obtaining the criterion comparison result also include:

[0021] If the current operating mode is in the first type of operating mode, the first criterion is used to compare the transformer loss in the current mode, the minimum transformer loss when switching to the second type of operating mode, and the transformer loss when switching to the third type of operating mode to obtain the criterion comparison result.

[0022] If the current operating mode is the second type of operating mode, the minimum transformer loss when switching to the second type of operating mode is determined as the transformer loss of the current mode, and the second criterion is used to compare the transformer loss of the current mode, the transformer loss when switching to the first type of operating mode, and the transformer loss when switching to the third type of operating mode to obtain the criterion comparison result.

[0023] If the current operating mode is in the third type of operating mode, the third criterion is used to compare the transformer loss in the current mode, the transformer loss when switched to the first type of operating mode, the minimum transformer loss when switched to the second type of operating mode, and the maximum transformer loss when switched to the second type of operating mode, and obtain the criterion comparison result.

[0024] In one embodiment, the step of determining the number of main transformers that need to be put into operation among the first, second, and third main transformers based on the criterion comparison results includes:

[0025] If the transformer loss in the current operating mode is in the first type of operating mode, and the transformer loss in the current mode is less than or equal to the minimum transformer loss in the second type of operating mode, then automatic switching will not be performed; if the minimum transformer loss when switching to the second type of operating mode is greater than or equal to the transformer loss when switching to the third type of operating mode, and less than or equal to the transformer loss in the current mode, then the number of main transformers to be put into operation is determined to be 1; if the transformer loss in the current mode, the minimum transformer loss when switching to the second type of operating mode, and the transformer loss when switching to the third type of operating mode all do not meet the above relationship, then the number of main transformers to be put into operation is determined to be 2.

[0026] If the transformer loss when switching to the third operating mode is greater than or equal to the transformer loss when switching to the first operating mode, and less than or equal to the transformer loss in the current mode, then the number of main transformers to be put into operation is determined to be 3; if the transformer loss when switching to the first operating mode is greater than or equal to the transformer loss when switching to the third operating mode, and less than or equal to the transformer loss in the current mode, then the number of main transformers to be put into operation is determined to be 1; if the transformer loss in the current mode, the transformer loss when switching to the first operating mode, and the transformer loss when switching to the third operating mode do not meet the above relationship, then automatic switching will not be performed.

[0027] If the current operating mode is in the third type of operating mode, and the minimum transformer loss when switching to the second type of operating mode is greater than or equal to the transformer loss when switching to the first type of operating mode, and less than or equal to the transformer loss in the current mode, then the number of main transformers to be put into operation is determined to be 3; if the transformer loss when switching to the first type of operating mode is greater than or equal to the maximum transformer loss when switching to the second type of operating mode, and less than or equal to the transformer loss in the current mode, then the number of main transformers to be put into operation is determined to be 2; if the transformer loss in the current mode, the transformer loss when switching to the first type of operating mode, the minimum transformer loss when switching to the second type of operating mode, and the maximum transformer loss when switching to the second type of operating mode do not meet the above relationship, then automatic switching will not be performed.

[0028] In one embodiment, if the current operating mode is not the most economical operating mode, after the step of switching the first main transformer, the second main transformer, the third main transformer, the first sectionalizing switch, and the second sectionalizing switch based on the most economical operating mode, the method further includes:

[0029] When the most economical operating mode is the first type of operating mode, the substation does not perform automatic switching;

[0030] When the most economical operating mode is the second type of operating mode, the substation rotates sequentially between the second, fourth, fifth, sixth, and seventh operating modes according to a preset cycle. The fourth operating mode includes the first main transformer not being engaged, both the second and third main transformers being engaged, and both the first and second sectionalizing switches being closed. The fifth operating mode includes both the first and third main transformers being engaged, the second main transformer not being engaged, and both the first and second sectionalizing switches being closed. The sixth operating mode includes both the first and second main transformers being engaged, the third main transformer not being engaged, the first sectionalizing switch being open, and the second sectionalizing switch being closed. The seventh operating mode includes both the first and second main transformers being engaged, the third main transformer not being engaged, and both the first and second sectionalizing switches being closed.

[0031] When the most economical operating mode is the third type of operating mode, the substation rotates between the third and fifth operating modes according to a preset cycle.

[0032] Secondly, this application also provides an automatic switching device for backup power supply in substations. The device includes:

[0033] The acquisition module is used to acquire the rated parameters, operating parameters, and current operating mode of the substation.

[0034] The processing module is used to process rated parameters and operating parameters based on the current operating mode using a preset model to determine the most economical operating mode of the substation; the preset model aims to minimize the total transformer loss.

[0035] The switching module is used to switch the first main transformer, the second main transformer, the third main transformer, the first sectionalizing switch, and the second sectionalizing switch respectively, based on the most economical operating mode, if the current operating mode is not the most economical operating mode.

[0036] Thirdly, this application also provides an automatic switching system for substation backup power. The system includes a substation and a switching device, which includes a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the steps of the method described above.

[0037] Fourthly, this application also provides a computer-readable storage medium. The computer-readable storage medium stores a computer program thereon, which, when executed by a processor, implements the steps of the above-described method.

[0038] Fifthly, this application also provides a computer program product. The computer program product includes a computer program that, when executed by a processor, implements the steps of the above-described method.

[0039] The aforementioned automatic switching methods, devices, systems, storage media, and computer programs for substation backup power supplies can automatically select the operating mode of the transformer and automatically switch it on and off based on the principle of minimizing total transformer losses. By automatically judging and adjusting the transformer to operate in the most economical mode, it helps the transformer to operate in the mode with the least loss, which can achieve the effects of energy saving and emission reduction, reducing the workload of substation operators, and improving the level of substation automation. Attached Figure Description

[0040] Figure 1 This is one embodiment of the substation wiring method;

[0041] Figure 2 This is a flowchart illustrating a method for automatically switching on backup power to a substation in one embodiment.

[0042] Figure 3 This is a flowchart illustrating the automatic switching steps of a substation backup power supply in one embodiment.

[0043] Figure 4 This is an internal structural diagram of the cutting device in one embodiment. Detailed Implementation

[0044] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0045] It should be noted that 10kV neutral grounding devices generally include two types: grounding transformers and arc suppression coils. Substations usually choose one of the two, and the operating principles of the two are the same. This application uses grounding transformers as an example for explanation, but the relevant schemes are also applicable to arc suppression coils.

[0046] In one embodiment, this application provides a method for automatically switching on backup power to a substation. For example... Figure 1 As shown, the method is applied to, for example Figure 1 The wiring diagram shown pertains to a substation comprising a first main transformer 110, a second main transformer 120, and a third main transformer 130. The high-voltage sides of all three transformers are connected to the power transmission network. The low-voltage side of the first main transformer 110 is connected to the first busbar. The low-voltage side of the second main transformer 120 is connected to both the second and third busbars. The low-voltage side of the third main transformer 130 is connected to the fourth busbar. The first and second busbars are connected via a first sectionalizing switch 140. The third and fourth busbars are connected via a second sectionalizing switch 150. Figure 2 As shown, the method includes:

[0047] Step 210: Obtain the rated parameters, operating parameters, and current operating mode of the substation;

[0048] Specifically, the rated parameters of the substation may include the rated parameters of the first main transformer 110, the second main transformer 120, and the third main transformer 130; the operating parameters of the substation may include the current current of the first sectionalizing switch 140 and the current current of the second sectionalizing switch 150; the current operating mode of the substation may include the switching status of the first main transformer 110, the second main transformer 120, the third main transformer 130, the first sectionalizing switch 140, and the second sectionalizing switch 150.

[0049] In some examples, the substation's operating modes may include three types: the first operating mode has 3 main transformers in operation; the second operating mode has 2 main transformers in operation; and the third operating mode has 1 main transformer in operation.

[0050] Step 220: Using a preset model to process rated parameters and operating parameters based on the current operating mode, determine the most economical operating mode of the substation; the preset model aims to minimize the total transformer loss.

[0051] Specifically, the most economical operating mode of a substation can refer to the most economical operating mode of its transformers. Economical transformer operation means minimizing transformer energy loss by selecting the optimal operating mode and adjusting the load under the same power transmission conditions. In some examples, the substation operating mode with the lowest total transformer loss is determined as the most economical operating mode of the substation.

[0052] Step 230: If the current operating mode is not the most economical operating mode, the first main transformer 110, the second main transformer 120, the third main transformer 130, the first sectionalizing switch 140 and the second sectionalizing switch 150 are switched on and off respectively based on the most economical operating mode.

[0053] Specifically, the substation includes three main transformers and four 10kV busbars. The low-voltage side of the second main transformer 120 includes two branches, connected to the second and third busbars respectively. The first sectionalizing switch 140 and the second sectionalizing switch 150 are 10kV sectionalizing switches. The first main transformer 110 is connected to the transmission network via a first high-voltage switch (1101) and to the first busbar via a first low-voltage switch (501). The second main transformer 120 is connected to the transmission network via a second high-voltage switch (1102), to the second busbar via a second low-voltage switch (502A), and to the third busbar via a third low-voltage switch (502B). The third main transformer 130 is connected to the transmission network via the third high-voltage switch (1103) and to the fourth busbar via the fourth low-voltage switch (503); the first busbar is connected to the first grounding transformer via the first grounding switch (D01); the second busbar is connected to the second grounding transformer via the second grounding switch (D02); the fourth busbar is connected to the third grounding transformer via the third grounding switch (D03); the first busbar is connected to the first grounding transformer via the first grounding switch (D01); the second busbar is connected to the second grounding transformer via the second grounding switch (D02); the fourth busbar is connected to the third grounding transformer via the third grounding switch (D03);

[0054] In some examples, the first main transformer 110 can be switched by switching the first high-voltage switch (1101) and the first low-voltage switch (501); the second main transformer 120 can be switched by switching the second high-voltage switch (1102) and the second low-voltage switch (502A), or by switching the second high-voltage switch (1102) and the third low-voltage switch (502B); and the third main transformer 130 can be switched by switching the third high-voltage switch (1103) and the fourth low-voltage switch (503).

[0055] This embodiment, based on the principle of minimizing total transformer losses, can automatically select the transformer's operating mode and automatically switch it on and off. By automatically judging and adjusting the transformer to operate in the most economical mode, it helps the transformer to operate in the mode with the least loss, which can achieve the effects of energy saving and emission reduction, reducing the workload of substation operators, and improving the level of substation automation.

[0056] In one embodiment, the step of determining the most economical operating mode of a substation by using a preset model to process rated parameters and operating parameters based on the current operating mode includes:

[0057] Based on the current operating mode, the rated parameters and operating parameters are processed to obtain the transformer loss under the current mode; the rated parameters and operating parameters are then converted to obtain the expected transformer loss after switching.

[0058] The substation's operating parameters are processed using a pre-set model to obtain the current transformer loss and the expected transformer loss after switching. The rated parameters include the rated parameters of the first main transformer 110, the second main transformer 120, and the third main transformer 130. The operating parameters include the current current of the first sectionalizing switch 140 and the current current of the second sectionalizing switch 150.

[0059] Based on the current operating mode, select the appropriate criteria, compare the transformer loss under the current mode with the expected transformer loss after switching, and obtain the criterion comparison results.

[0060] Specifically, the rated parameters of the first main transformer 110 may include the rated secondary current, the rated no-load loss, and the rated load loss of the first main transformer 110; the rated parameters of the second main transformer 120 and the third main transformer 130 are similar.

[0061] In one embodiment, the method further includes:

[0062] Based on the comparison results of the criteria, the number of main transformers that need to be put into operation among the first main transformer 110, the second main transformer 120 and the third main transformer 130 is determined.

[0063] If the number of main transformers to be put into operation is 3, then the first operating mode is determined as the most economical operating mode. The first operating mode includes the first main transformer 110, the second main transformer 120 and the third main transformer 130 being put into operation, and the first sectionalizing switch 140 and the second sectionalizing switch 150 being in the open state.

[0064] If the number of main transformers to be put into operation is 2, then the second operating mode is determined as the most economical operating mode. The second operating mode includes the first main transformer 110 not being put into operation, the second main transformer 120 and the third main transformer 130 being put into operation, the first sectionalizing switch 140 being closed, and the second sectionalizing switch 150 being open.

[0065] If the number of main transformers to be put into operation is 1, then the third operating mode is determined as the most economical operating mode. The third operating mode includes that neither the first main transformer 110 nor the third main transformer 130 is put into operation, the second main transformer 120 is put into operation, and the first sectionalizing switch 140 and the second sectionalizing switch 150 are both in the closed state.

[0066] Specifically, in the first operating mode, the first high-voltage switch (1101), the second high-voltage switch (1102), the third high-voltage switch (1103), the first low-voltage switch (501), the second low-voltage switch (502A), the third low-voltage switch (502B), the fourth low-voltage switch (503), the first grounding switch (D01), the second grounding switch (D02), and the third grounding switch (D03) are all in the closed state; the first sectionalizing switch 140 and the second sectionalizing switch 150 are both in the open state.

[0067] The second operating mode includes the second high-voltage switch (1102), the third high-voltage switch (1103), the second low-voltage switch (502A), the third low-voltage switch (502B), the fourth low-voltage switch (503), the second grounding switch (D02), the third grounding switch (D03), and the first sectionalizing switch 140 all being in the closed state; the first high-voltage switch (1101), the first low-voltage switch (501), the first grounding switch (D01), and the second sectionalizing switch 150 are all in the open state;

[0068] The third operating mode includes the second high-voltage switch (1102), the second low-voltage switch (502A), the third low-voltage switch (502B), the second grounding switch (D02), the first sectionalizing switch 140, and the second sectionalizing switch 150 all being closed; and the first high-voltage switch (1101), the first low-voltage switch (501), the first grounding switch (D01), the third high-voltage switch (1103), the fourth low-voltage switch (503), and the third grounding switch (D03) all being open.

[0069] In one embodiment, the substation's operation mode categories include a first operation mode, a second operation mode, and a third operation mode; wherein, the number of main transformers put into operation in the first operation mode is 3; the number of main transformers put into operation in the second operation mode is 2; and the number of main transformers put into operation in the third operation mode is 1.

[0070] The steps of selecting the appropriate criterion based on the current operating mode, comparing the transformer loss under the current mode with the expected transformer loss after switching, and obtaining the criterion comparison result also include:

[0071] If the current operating mode is in the first type of operating mode, the first criterion is used to compare the transformer loss in the current mode, the minimum transformer loss when switching to the second type of operating mode, and the transformer loss when switching to the third type of operating mode to obtain the criterion comparison result.

[0072] If the current operating mode is the second type of operating mode, the minimum transformer loss when switching to the second type of operating mode is determined as the transformer loss of the current mode, and the second criterion is used to compare the transformer loss of the current mode, the transformer loss when switching to the first type of operating mode, and the transformer loss when switching to the third type of operating mode to obtain the criterion comparison result.

[0073] If the current operating mode is in the third type of operating mode, the third criterion is used to compare the transformer loss in the current mode, the transformer loss when switched to the first type of operating mode, the minimum transformer loss when switched to the second type of operating mode, and the maximum transformer loss when switched to the second type of operating mode, and obtain the criterion comparison result.

[0074] In one embodiment, the step of determining the number of main transformers to be put into operation among the first main transformer 110, the second main transformer 120, and the third main transformer 130 based on the criterion comparison result includes:

[0075] If the transformer loss in the current operating mode is in the first type of operating mode, and the transformer loss in the current mode is less than or equal to the minimum transformer loss in the second type of operating mode, then automatic switching will not be performed; if the minimum transformer loss when switching to the second type of operating mode is greater than or equal to the transformer loss when switching to the third type of operating mode, and less than or equal to the transformer loss in the current mode, then the number of main transformers to be put into operation is determined to be 1; if the transformer loss in the current mode, the minimum transformer loss when switching to the second type of operating mode, and the transformer loss when switching to the third type of operating mode all do not meet the above relationship, then the number of main transformers to be put into operation is determined to be 2.

[0076] If the transformer loss when switching to the third operating mode is greater than or equal to the transformer loss when switching to the first operating mode, and less than or equal to the transformer loss in the current mode, then the number of main transformers to be put into operation is determined to be 3; if the transformer loss when switching to the first operating mode is greater than or equal to the transformer loss when switching to the third operating mode, and less than or equal to the transformer loss in the current mode, then the number of main transformers to be put into operation is determined to be 1; if the transformer loss in the current mode, the transformer loss when switching to the first operating mode, and the transformer loss when switching to the third operating mode do not meet the above relationship, then automatic switching will not be performed.

[0077] If the current operating mode is in the third type of operating mode, and the minimum transformer loss when switching to the second type of operating mode is greater than or equal to the transformer loss when switching to the first type of operating mode, and less than or equal to the transformer loss in the current mode, then the number of main transformers to be put into operation is determined to be 3; if the transformer loss when switching to the first type of operating mode is greater than or equal to the maximum transformer loss when switching to the second type of operating mode, and less than or equal to the transformer loss in the current mode, then the number of main transformers to be put into operation is determined to be 2; if the transformer loss in the current mode, the transformer loss when switching to the first type of operating mode, the minimum transformer loss when switching to the second type of operating mode, and the maximum transformer loss when switching to the second type of operating mode do not meet the above relationship, then automatic switching will not be performed.

[0078] Specifically, to select the most economical operating mode of a substation with the goal of minimizing total transformer losses, one approach is to convert the current operating mode into other operating modes and then select the one with the lowest total transformer losses as the most economical operating mode. In some examples, determining the most economical operating mode requires six conversion calculations each time, increasing the complexity of the determination. For the second type of operating mode, which involves two main transformers, the process can be simplified to obtaining the theoretical maximum and minimum values ​​of total transformer losses under this mode. By comparing the first operating mode of the first type of operating mode, the maximum and minimum values ​​of total transformer losses under the second type of operating mode, and the third operating mode of the third type of operating mode, the number of main transformers that should be put into operation can be determined. If the determination result is that two main transformers should be put into operation, then the second operating mode is confirmed as the most economical operating mode.

[0079] For the second and third operating modes, when the total load is constant, regardless of how the load is distributed among the main transformers, the total transformer loss ΔP ∑ Must satisfy:

[0080] ΔP ∑·min ≤ΔP ∑ ≤ΔP ∑·max

[0081] If the current operating mode is the first type of operating mode, then ΔP ∑·1 ≤ΔP ∑·min Maintain the current operating mode and do not perform automatic switching; if In the case of 1, the number of main transformers to be put into operation is determined to be 1; in the other cases, the number of main transformers to be put into operation is determined to be 2.

[0082] If the current operating mode is the second type of operating mode, then ΔP ∑·1 ≤ΔP ∑·3 ≤ΔP ∑·minThen the number of main transformers that need to be put into operation is determined to be 3; if ΔP ∑·3 ≤ΔP ∑·1 ≤ΔP ∑·min If the number of main transformers to be put into operation is 1, then the original method will be maintained and automatic switching will not be performed.

[0083] If the current operating mode is the third type of operating mode, then ΔP ∑·1 ≤ΔP ∑·min ≤ΔP ∑·3 If ΔP ∑·max ≤ΔP ∑·1 ≤ΔP ∑·3 If the current mode is not specified, the system will automatically switch to operating mode 2; otherwise, the current mode will remain unchanged.

[0084] Where, ΔP ∑·1 The total loss of the transformer currently operating in or switched to the first type of operating mode; ΔP ∑·min ΔP is the minimum total loss of a transformer currently operating in or switched to the second type of operating mode. ∑·max ΔP represents the maximum total loss of a transformer currently operating in or switched to the second operating mode; ∑·3 The total loss of the transformer currently operating in or switched to the third operating mode; P 02 I is the rated no-load loss of the second main transformer 120, and I is the sum of the low-voltage currents of the first main transformer 110, the second main transformer 120, and the third main transformer 130. e2 For the second main transformer 120, reduce the rated current, P S2 This is the rated load loss of the second main transformer 120;

[0085] In some examples, when the current operating mode is the first type of operating mode, if ΔP ∑·1 ≤ΔP ∑·min Maintain the current operating mode and do not perform automatic switching; if In the case of automatic switching, the system will automatically switch to the third operating mode; otherwise, it will automatically switch to the second operating mode.

[0086] If the current operating mode is the second type of operating mode, then ΔP ∑·1 ≤ΔP ∑·3 ≤ΔP ∑·min Then it will automatically switch to the first operating mode; if ΔP ∑·3 ≤ΔP ∑·1 ≤ΔP ∑·minIf the automatic switching occurs, the system will automatically switch to the third operating mode; otherwise, it will maintain the current operating mode and will not perform automatic switching.

[0087] If the current operating mode is the third type of operating mode, then ΔP ∑·1 ≤ΔP ∑·min ≤ΔP ∑·3 Then it will automatically switch to the first operating mode; if ΔP ∑·max ≤ΔP ∑·1 ≤ΔP ∑·3 When the current operating mode is reached, the system will automatically switch to the second operating mode; otherwise, the current operating mode will be maintained and automatic switching will not be performed.

[0088] In some examples, taking the current operating mode as the first type of operating mode as an example, the transformer loss ΔP in the current operating mode is... ∑ It can be calculated in the following way;

[0089]

[0090] Where, ΔP i The loss value of the i-th main transformer can be calculated using the following formula:

[0091]

[0092] Among them, P 0i I represents the rated no-load loss of the i-th main transformer; i Ii is the current current of the low-voltage switch of the i-th main transformer (I2 is the sum of the current currents of the second low-voltage switch (502A) and the third low-voltage switch (502B)); Ii ei The i-th main transformer is reduced to a lower rated current; P Si Let be the rated load loss of the i-th main transformer;

[0093] The minimum total loss ΔP of the transformer when switched to the second type of operation mode. ∑·min It can be calculated using the following formula:

[0094]

[0095] The maximum total loss ΔP of the transformer when switched to the second type of operation mode ∑·max It can be calculated using the following formula:

[0096]

[0097] in,

[0098] P 0·min =min(P 01 ,P 02 ,P 03 )

[0099] P 0·max =max(P 01 ,P 02 ,P 03 )

[0100] I = I1 + I 2A +I 2B +I3

[0101] I e·max =max(I e1 ,I e2 ,I e3 )

[0102] I e·min =min(I e1 ,I e2 ,I e3 )

[0103] P S·min =min(P S1 ,P S2 ,P S3 )

[0104] P S·max =max(P S1 ,P S2 ,P S3 )

[0105] Similarly, if the current operating mode is in the second or third type of operating mode, the transformer loss under the current operating mode will still be calculated as ΔP. ∑ The calculated low-current of each main transformer in the first and third operating modes required for the calculation can be obtained through simple calculation based on the conversion relationship between the current operating mode and other operating modes.

[0106] In some examples, the positions of the main transformer's high-voltage switch, neutral point disconnector, low-voltage switch, and 10kV sectionalizing switch can be obtained through the auxiliary contact of the switch. Parameters such as the no-load loss, load loss, and low-voltage rated current of the main transformer can be entered into the automatic transfer switch based on the nameplate parameters of the main transformer. The current of the low-voltage switch and the 10kV sectionalizing switch of the main transformer can be obtained from the secondary circuit of the CT of each switch.

[0107] In one embodiment, if the current operating mode is not the most economical operating mode, after the step of switching the first main transformer 110, the second main transformer 120, the third main transformer 130, the first sectionalizing switch 140, and the second sectionalizing switch 150 based on the most economical operating mode, the method further includes:

[0108] When the most economical operating mode is the first type of operating mode, the substation does not perform automatic switching;

[0109] When the most economical operating mode is the second type of operating mode, the substation rotates sequentially between the second, fourth, fifth, sixth, and seventh operating modes according to a preset cycle. The fourth operating mode includes the first main transformer 110 not being engaged, the second main transformer 120 and the third main transformer 130 both being engaged, and the first sectionalizing switch 140 and the second sectionalizing switch 150 both being closed. The fifth operating mode includes the first main transformer 110 and the third main transformer 130 both being engaged, the second main transformer 120 not being engaged, and the first sectionalizing switch 140 and the second sectionalizing switch 150 both being closed. The sixth operating mode includes the first main transformer 110 and the second main transformer 120 both being engaged, the third main transformer 130 not being engaged, the first sectionalizing switch 140 being open, and the second sectionalizing switch 150 being closed. The seventh operating mode includes the first main transformer 110 and the second main transformer 120 both being engaged, the third main transformer 130 not being engaged, and the first sectionalizing switch 140 and the second sectionalizing switch 150 both being closed.

[0110] When the most economical operating mode is the third type of operating mode, the substation rotates between the third and fifth operating modes according to a preset cycle.

[0111] Specifically, in the fourth operating mode, the second high-voltage switch (1102), the third high-voltage switch (1103), the second low-voltage switch (502A), the fourth low-voltage switch (503), the first sectionalizing switch 140, the second sectionalizing switch 150, the second grounding switch (D02), and the third grounding switch (D03) are all in the closed state; the first high-voltage switch (1101), the first low-voltage switch (501), the first grounding switch (D01), and the third low-voltage switch (502B) are all in the open state.

[0112] The fifth operating mode includes the first high-voltage switch (1101), the first low-voltage switch (501), the first grounding switch (D01), the first sectionalizing switch 140, the second sectionalizing switch 150, the third high-voltage switch (1103), the fourth low-voltage switch (503), and the third grounding switch (D03) all being closed; the second high-voltage switch (1102), the second low-voltage switch (502A), the third low-voltage switch (502B), and the second grounding switch (D02) all being open.

[0113] The sixth operating mode includes the following: the first high-voltage switch (1101), the second high-voltage switch (1102), the first low-voltage switch (501), the second low-voltage switch (502A), the third low-voltage switch (502B), the first grounding switch (D01), the second grounding switch (D02), and the second sectionalizing switch 150 are all in the closed state; the first sectionalizing switch 140, the third high-voltage switch (1103), the fourth low-voltage switch (503), and the third grounding switch (D03) are all in the open state.

[0114] The seventh operating mode includes the following: the first high-voltage switch (1101), the second high-voltage switch (1102), the first low-voltage switch (501), the third low-voltage switch (502B), the first sectionalizing switch 140, the second sectionalizing switch 150, the first grounding switch (D01), and the second grounding switch (D02) are all in the closed state; the second low-voltage switch (502A), the fourth low-voltage switch (503), the third high-voltage switch (1103), and the second grounding switch (D02) are all in the open state.

[0115] Specifically, in the traditional control strategy for switching to backup power after a 10kV busbar loss, the control of the main transformer's low-voltage switch and 10kV sectionalizing switch is involved. The main transformer's high-voltage switch, transformer neutral point, and 10kV neutral point grounding device all require corresponding operations. Traditional 10kV automatic transfer switch control strategies do not involve the operation of these switches and disconnectors. For these switches and disconnectors, after the automatic transfer switch is activated, they need to be manually operated to a state matching the operating mode according to the operating principles. This application proposes a method to simultaneously perform coordinated operations on the main transformer's high-voltage switch, transformer neutral point, main transformer low-voltage switch, 10kV sectionalizing switch, and 10kV neutral point grounding device according to the most economical operating mode, thus solving the problem of still needing to manually operate related switches and disconnectors after the automatic transfer switch is activated.

[0116] Automatic switching of transformer high-voltage switches, transformer neutral points, transformer low-voltage switches, 10kV sectionalizing switches, and 10kV neutral grounding devices includes: determining whether and how to perform a linkage operation on the transformer neutral point when switching transformer high-voltage switches and low-voltage switches, based on the setting of control words such as "automatic switching of main transformer neutral point" and "normal operation of main transformer with neutral point in closed position"; and determining whether and how to perform a linkage operation on the 10kV neutral grounding device when switching transformer high-voltage switches, low-voltage switches, and 10kV sectionalizing switches, based on the setting of the "automatic switching of 10kV neutral point" control word and the position of the transformer high-voltage side bus tie switch.

[0117] In some examples, such as Figure 3As shown, the switching strategy consists of three parts: overall strategy, transformer input strategy, and transformer de-in strategy.

[0118] The overall strategy includes: the automatic transfer switch automatically determines whether the most economical operating mode has changed every T time interval based on the current of the low-voltage switch of each main transformer and the current of the 10kV sectionalizing switch. The T time interval can be a preset value. If the most economical operating mode changes, the switching is performed according to the most economical operating mode. If the most economical operating mode does not change, the automatic rotation strategy is performed. Whether it is operating mode switching or automatic rotation, it involves the commissioning or decommissioning of the main transformer, that is, it involves transformer commissioning strategy and transformer decommissioning strategy.

[0119] The transformer commissioning strategy includes: determining whether it is necessary to operate the transformer neutral point disconnect switch based on the "automatic switching of main transformer neutral point" control word (which can be set); if it is necessary to automatically switch the main transformer neutral point, then close the neutral point disconnect switch of the main transformer to be commissioned; otherwise, proceed directly to the next step.

[0120] Determine whether the bus tie switch of the main transformer's high-voltage switch is in the closed position. If the bus tie switch is in the closed position, first close the main transformer's low-voltage switch and then disconnect the 10kV sectionalizing switch to avoid power loss on the 10kV bus during this process. If the bus tie switch is in the open position, first disconnect the 10kV sectionalizing switch and then close the main transformer's low-voltage switch to avoid electromagnetic loops during this process.

[0121] Regardless of the operating method, after closing the low-voltage switch of the main transformer, determine whether it is necessary to operate the 10kV neutral point grounding device according to the "10kV neutral point automatic switching" control word (which can be set); if it is necessary to automatically switch the 10kV neutral point, close the 10kV neutral point grounding device switch; otherwise, proceed directly to the next step.

[0122] Based on the "Automatic Neutral Point Switching of Main Transformer" control word (adjustable), determine whether operation of the transformer neutral point disconnector is required. If automatic switching of the main transformer neutral point is required, determine whether the neutral point of this transformer needs to be opened based on the "Normal Point Closed During Normal Operation of Main Transformer" control word (adjustable, there are three such control words, one for each of the three transformers). If the current transformer's "Normal Point Closed During Normal Operation of Main Transformer" control word is 1, it indicates that the current transformer neutral point grounding switch is closed during normal operation, and no operation is performed on the transformer's neutral point grounding switch (it has already been closed in the previous control strategy). If the control word is 0, it indicates that the transformer neutral point grounding switch is open during normal operation, and the transformer neutral point grounding switch needs to be opened. If automatic switching of the main transformer neutral point is not required, the transformer connection process ends directly.

[0123] The transformer shutdown strategy includes: determining whether the transformer neutral point disconnector needs to be operated based on the "Automatic Switching of Main Transformer Neutral Point" control word. If automatic switching of the main transformer neutral point is required, the neutral point disconnector of the transformer to be shut down is closed; otherwise, proceed directly to the next step.

[0124] Determine whether the bus tie switch on the busbar where the transformer high-voltage switch is located is in the closed position. If the bus tie switch is in the closed position, the operation method is to first close the 10kV sectionalizing switch, then disconnect the transformer low-voltage switch, and finally disconnect the transformer high-voltage switch to ensure that the 10kV busbar does not lose power during this process. If the bus tie switch is in the open position, the operation method is to first disconnect the transformer low-voltage switch, then close the 10kV sectionalizing switch, and finally disconnect the transformer high-voltage switch to avoid the formation of an electromagnetic loop during this process and to minimize the power loss time of the 10kV busbar.

[0125] Regardless of the operating method, after closing the 10kV sectionalizing switch, the system will determine whether operation of the 10kV neutral point grounding device is required based on the "10kV Neutral Point Automatic Switching" control word. If automatic switching of the 10kV neutral point is required, the 10kV neutral point grounding device switch will be disconnected; otherwise, proceed directly to the next step.

[0126] The system determines whether operation of the transformer neutral point disconnector is required based on the "Automatic Switching of Main Transformer Neutral Point" control word. If automatic switching of the main transformer neutral point is required, the transformer neutral point is directly opened (since the neutral point grounding switch needs to be opened even when the transformer is out of service, the "Normal Point Closed During Normal Transformer Operation" control word for this transformer is not needed); if automatic switching of the main transformer neutral point is not required, the transformer connection process is directly terminated.

[0127] This embodiment proposes a linkage strategy for five types of switches—the transformer high-voltage switch, transformer neutral grounding switch, transformer low-voltage switch, 10kV sectionalizing switch, and 10kV neutral grounding device—when a transformer is put into operation or taken out of operation. This strategy ensures that all relevant switches can be automatically and seamlessly controlled by the automatic transfer switch (ATS). It also enables periodic automatic rotation when not all transformers are in operation. By automatically rotating the working and standby transformers periodically, the operating time of each transformer can be ensured to be relatively uniform. This eliminates the need for manual intervention, reducing the workload of substation operators and improving the level of substation automation.

[0128] It should be understood that although the steps in the flowcharts of the embodiments described above are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the embodiments described above may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the steps or stages of other steps.

[0129] Based on the same inventive concept, this application also provides an automatic substation backup power supply device for implementing the aforementioned automatic substation backup power supply method. The solution provided by this device is similar to the solution described in the above method; therefore, the specific limitations in one or more embodiments of the automatic substation backup power supply device provided below can be found in the limitations of the automatic substation backup power supply method described above, and will not be repeated here.

[0130] In one embodiment, this application also provides an automatic switching device for backup power supply in a substation. The device includes:

[0131] The acquisition module is used to acquire the rated parameters, operating parameters, and current operating mode of the substation.

[0132] The processing module is used to process rated parameters and operating parameters based on the current operating mode using a preset model to determine the most economical operating mode of the substation; the preset model aims to minimize the total transformer loss.

[0133] The switching module is used to switch the first main transformer 110, the second main transformer 120, the third main transformer 130, the first sectionalizing switch 140, and the second sectionalizing switch 150 respectively based on the most economical operating mode if the current operating mode is not the most economical operating mode.

[0134] In one embodiment, the processing module is further configured to process rated parameters and operating parameters based on the current operating mode to obtain the transformer loss under the current mode; perform conversion processing on the rated parameters and operating parameters to obtain the expected transformer loss after switching; process the operating parameters of the substation using a preset model of the substation to obtain the transformer loss under the current mode and the expected transformer loss after switching; the rated parameters include the rated parameters of the first main transformer, the rated parameters of the second main transformer, and the rated parameters of the third main transformer; the operating parameters include the current current of the first sectionalizing switch and the current current of the second sectionalizing switch; select a corresponding criterion based on the current operating mode, compare the transformer loss under the current mode and the expected transformer loss after switching, and obtain the criterion comparison result.

[0135] In one embodiment, the processing module is further configured to determine the number of main transformers that need to be put into operation among the first main transformer, the second main transformer, and the third main transformer based on the criterion comparison results.

[0136] If the number of main transformers to be put into operation is 3, then the first operating mode is determined as the most economical operating mode; the first operating mode includes the first main transformer, the second main transformer and the third main transformer being put into operation, and the first sectionalizing switch and the second sectionalizing switch being in the open state.

[0137] If the number of main transformers to be put into operation is 2, then the second operating mode is determined as the most economical operating mode. The second operating mode includes the first main transformer not being put into operation, the second and third main transformers being put into operation, the first sectionalizing switch being closed, and the second sectionalizing switch being open.

[0138] If the number of main transformers to be put into operation is 1, then the third operating mode is determined as the most economical operating mode. The third operating mode includes the following: neither the first main transformer nor the third main transformer is put into operation, the second main transformer is put into operation, and both the first sectionalizing switch and the second sectionalizing switch are in the closed state.

[0139] In one embodiment, the processing module is further configured to, if the current operating mode is in the first type of operating mode, use a first criterion to compare the transformer loss of the current mode, the minimum transformer loss when switching to the second type of operating mode, and the transformer loss when switching to the third type of operating mode, and obtain the criterion comparison result.

[0140] If the current operating mode is the second type of operating mode, the minimum transformer loss when switching to the second type of operating mode is determined as the transformer loss of the current mode, and the second criterion is used to compare the transformer loss of the current mode, the transformer loss when switching to the first type of operating mode, and the transformer loss when switching to the third type of operating mode to obtain the criterion comparison result.

[0141] If the current operating mode is in the third type of operating mode, the third criterion is used to compare the transformer loss in the current mode, the transformer loss when switched to the first type of operating mode, the minimum transformer loss when switched to the second type of operating mode, and the maximum transformer loss when switched to the second type of operating mode, and obtain the criterion comparison result.

[0142] In one embodiment, the processing module is further configured to, when the current operating mode is in the first type of operating mode, if the transformer loss in the current mode is less than or equal to the minimum transformer loss in the second type of operating mode, then no automatic switching is performed; if the minimum transformer loss when switching to the second type of operating mode is greater than or equal to the transformer loss when switching to the third type of operating mode, and less than or equal to the transformer loss in the current mode, then the number of main transformers to be put into operation is determined to be 1; if the transformer loss in the current mode, the minimum transformer loss when switching to the second type of operating mode, and the transformer loss when switching to the third type of operating mode all do not satisfy the above-mentioned size relationship, then the number of main transformers to be put into operation is determined to be 2.

[0143] If the transformer loss when switching to the third operating mode is greater than or equal to the transformer loss when switching to the first operating mode, and less than or equal to the transformer loss in the current mode, then the number of main transformers to be put into operation is determined to be 3; if the transformer loss when switching to the first operating mode is greater than or equal to the transformer loss when switching to the third operating mode, and less than or equal to the transformer loss in the current mode, then the number of main transformers to be put into operation is determined to be 1; if the transformer loss in the current mode, the transformer loss when switching to the first operating mode, and the transformer loss when switching to the third operating mode do not meet the above relationship, then automatic switching will not be performed.

[0144] If the current operating mode is in the third type of operating mode, and the minimum transformer loss when switching to the second type of operating mode is greater than or equal to the transformer loss when switching to the first type of operating mode, and less than or equal to the transformer loss in the current mode, then the number of main transformers to be put into operation is determined to be 3; if the transformer loss when switching to the first type of operating mode is greater than or equal to the maximum transformer loss when switching to the second type of operating mode, and less than or equal to the transformer loss in the current mode, then the number of main transformers to be put into operation is determined to be 2; if the transformer loss in the current mode, the transformer loss when switching to the first type of operating mode, the minimum transformer loss when switching to the second type of operating mode, and the maximum transformer loss when switching to the second type of operating mode do not meet the above relationship, then automatic switching will not be performed.

[0145] In one embodiment, the apparatus further includes a rotation module for preventing automatic rotation of the substation when the most economical operating mode is the first type of operating mode;

[0146] When the most economical operating mode is the second type of operating mode, the substation rotates sequentially between the second, fourth, fifth, sixth, and seventh operating modes according to a preset cycle. The fourth operating mode includes the first main transformer not being engaged, both the second and third main transformers being engaged, and both the first and second sectionalizing switches being closed. The fifth operating mode includes both the first and third main transformers being engaged, the second main transformer not being engaged, and both the first and second sectionalizing switches being closed. The sixth operating mode includes both the first and second main transformers being engaged, the third main transformer not being engaged, the first sectionalizing switch being open, and the second sectionalizing switch being closed. The seventh operating mode includes both the first and second main transformers being engaged, the third main transformer not being engaged, and both the first and second sectionalizing switches being closed.

[0147] When the most economical operating mode is the third type of operating mode, the substation rotates between the third and fifth operating modes according to a preset cycle.

[0148] Each module in the aforementioned automatic transfer switch for substation backup power can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in or independent of the processor in a computer device, or stored in the computer device's memory as software, so that the processor can call and execute the corresponding operations of each module.

[0149] In one embodiment, this application also provides an automatic switching system for substation backup power. The system includes a substation and a switching device, which includes a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the steps of the method described above.

[0150] In one embodiment, a switching device is provided, which may be a server, and its internal structure diagram may be as follows: Figure 4 As shown, the switching device includes a processor, memory, and network interface connected via a system bus. The processor provides computing and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage media. The network interface is used to communicate with external terminals via a network connection. When the computer program is executed by the processor, it implements a method for automatically switching on backup power in a substation.

[0151] Those skilled in the art will understand that Figure 4The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the cutting device to which the present application is applied. A specific cutting device may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0152] In one embodiment, this application also provides a computer-readable storage medium. The computer-readable storage medium stores a computer program thereon, which, when executed by a processor, implements the steps of the method described above.

[0153] In one embodiment, this application also provides a computer program product. The computer program product includes a computer program that, when executed by a processor, implements the steps of the method described above.

[0154] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM). The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, etc., and are not limited to these.

[0155] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0156] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A method for automatically switching on backup power in a substation, characterized in that, An application is made in a substation comprising a first main transformer, a second main transformer, and a third main transformer. The high-voltage sides of the first, second, and third main transformers are all connected to a transmission network. The low-voltage side of the first main transformer is connected to a first busbar. The low-voltage side of the second main transformer is connected to both the second and third busbars. The low-voltage side of the third main transformer is connected to a fourth busbar. The first and second busbars are connected via a first sectionalizing switch. The third and fourth busbars are connected via a second sectionalizing switch. The first main transformer is connected to the transmission network via a first high-voltage switch and to the first busbar via a first low-voltage switch. The second main transformer is connected to the transmission network via a second high-voltage switch, to the second busbar via a second low-voltage switch, and to the third busbar via a third low-voltage switch. The third main transformer is connected to the transmission network via a third high-voltage switch and to the fourth busbar via a fourth low-voltage switch. The method includes: Obtain the rated parameters, operating parameters, and current operating mode of the substation; the rated parameters refer to the rated current, rated no-load loss, and rated load loss of the secondary side; the operating parameters refer to the current current of the first sectionalizing switch and the current current of the second sectionalizing switch. A preset model is used to process the rated parameters and the operating parameters based on the current operating mode to determine the most economical operating mode of the substation; the preset model aims to minimize the total transformer loss. If the current operating mode is not the most economical operating mode, the first main transformer, the second main transformer, the third main transformer, the first sectionalizing switch, and the second sectionalizing switch are switched on and off based on the most economical operating mode; wherein, the first main transformer is switched on and off by switching the first high-voltage switch and the first low-voltage switch; the second main transformer is switched on and off by switching the second high-voltage switch and the second low-voltage switch, or by switching the second high-voltage switch and the third low-voltage switch; and the third main transformer is switched on and off by switching the third high-voltage switch and the fourth low-voltage switch. The method further includes: Based on the comparison results of the criteria, the number of main transformers that need to be put into operation among the first main transformer, the second main transformer, and the third main transformer is determined; the comparison results of the criteria are obtained by comparing the transformer loss in the current mode with the expected transformer loss after switching; the transformer loss in the current mode and the expected transformer loss after switching are obtained by processing the operating parameters using the preset model; If the number of main transformers to be put into operation is 3, then the first operating mode is determined as the most economical operating mode; the first operating mode includes the first main transformer, the second main transformer and the third main transformer being put into operation, and the first sectionalizing switch and the second sectionalizing switch being in the open state; If the number of main transformers to be put into operation is 2, then the second operating mode is determined as the most economical operating mode; the second operating mode includes the first main transformer not being put into operation, the second main transformer and the third main transformer being put into operation, the first sectionalizing switch being closed, and the second sectionalizing switch being open. If the number of main transformers to be put into operation is 1, then the third operating mode is determined as the most economical operating mode; the third operating mode includes the first main transformer and the third main transformer not being put into operation, the second main transformer being put into operation, and the first sectionalizing switch and the second sectionalizing switch being in the closed state.

2. The method according to claim 1, characterized in that, The step of using a preset model to process the rated parameters and the operating parameters based on the current operating mode to determine the most economical operating mode of the substation includes: Based on the current operating mode, the rated parameters and the operating parameters are processed to obtain the transformer loss under the current mode; the rated parameters and the operating parameters are then converted to obtain the expected transformer loss after switching. The substation's operating parameters are processed using a preset model to obtain the current transformer loss and the expected transformer loss after switching. Based on the current operating mode, select the corresponding criterion, compare the transformer loss in the current mode with the expected transformer loss after switching, and obtain the criterion comparison result.

3. The method according to claim 2, characterized in that, The substation's operation modes include a first type, a second type, and a third type; wherein, the number of main transformers in operation under the first type is 3; the number of main transformers in operation under the second type is 2; and the number of main transformers in operation under the third type is 1. The step of selecting a corresponding criterion based on the current operating mode, comparing the transformer loss in the current mode with the expected transformer loss after switching, and obtaining the criterion comparison result further includes: If the current operating mode is in the first type of operating mode, then the transformer loss in the current mode, the minimum transformer loss when switching to the second type of operating mode, and the transformer loss when switching to the third type of operating mode are compared using the first criterion to obtain the criterion comparison result. If the current operating mode is in the second type of operating mode, then the minimum transformer loss when switching to the second type of operating mode is determined as the transformer loss of the current mode, and the transformer loss of the current mode, the transformer loss when switching to the first type of operating mode, and the transformer loss when switching to the third type of operating mode are compared using a second criterion to obtain the criterion comparison result. If the current operating mode is in the third type of operating mode, then the third criterion is used to compare the transformer loss in the current mode, the transformer loss when switched to the first type of operating mode, the minimum transformer loss when switched to the second type of operating mode, and the maximum transformer loss when switched to the second type of operating mode, and obtain the criterion comparison result.

4. The method according to claim 3, characterized in that, The step of determining the number of main transformers that need to be put into operation among the first main transformer, the second main transformer, and the third main transformer based on the comparison result of the criterion includes: When the current operating mode is in the first type of operating mode, if the transformer loss in the current mode is less than or equal to the minimum transformer loss in the second type of operating mode, then automatic switching will not be performed; if the minimum transformer loss when switching to the second type of operating mode is greater than or equal to the transformer loss when switching to the third type of operating mode, and less than or equal to the transformer loss in the current mode, then the number of main transformers to be put into operation is determined to be 1; if the transformer loss in the current mode, the minimum transformer loss when switching to the second type of operating mode, and the transformer loss when switching to the third type of operating mode all do not satisfy the above-mentioned relationship, then the number of main transformers to be put into operation is determined to be 2. When the current operating mode is the second type of operating mode, if the transformer loss when switching to the third type of operating mode is greater than or equal to the transformer loss when switching to the first type of operating mode and less than or equal to the transformer loss in the current mode, then the number of main transformers to be put into operation is determined to be 3; if the transformer loss when switching to the first type of operating mode is greater than or equal to the transformer loss when switching to the third type of operating mode and less than or equal to the transformer loss in the current mode, then the number of main transformers to be put into operation is determined to be 1; if the transformer loss in the current mode, the transformer loss when switching to the first type of operating mode, and the transformer loss when switching to the third type of operating mode all do not meet the above-mentioned relationship, then automatic switching will not be performed; When the current operating mode is in the third type of operating mode, if the minimum transformer loss when switching to the second type of operating mode is greater than or equal to the transformer loss when switching to the first type of operating mode and less than or equal to the transformer loss in the current mode, then the number of main transformers to be put into operation is determined to be 3; if the transformer loss when switching to the first type of operating mode is greater than or equal to the maximum transformer loss when switching to the second type of operating mode and less than or equal to the transformer loss in the current mode, then the number of main transformers to be put into operation is determined to be 2; if the transformer loss in the current mode, the transformer loss when switching to the first type of operating mode, the minimum transformer loss when switching to the second type of operating mode, and the maximum transformer loss when switching to the second type of operating mode all do not satisfy the above-mentioned size relationship, then automatic switching will not be performed.

5. The method according to claim 3 or 4, characterized in that, If the current operating mode is not the most economical operating mode, the step of switching the first main transformer, the second main transformer, the third main transformer, the first sectionalizing switch, and the second sectionalizing switch based on the most economical operating mode further includes: When the most economical operating mode is the first type of operating mode, the substation does not perform automatic switching; When the most economical operating mode is the second type of operating mode, the substation sequentially rotates between the second, fourth, fifth, sixth, and seventh operating modes according to a preset cycle. The fourth operating mode includes the first main transformer not being engaged, both the second and third main transformers being engaged, and both the first and second sectionalizing switches being closed. The fifth operating mode includes both the first and third main transformers being engaged, the second main transformer not being engaged, and both the first and second sectionalizing switches being closed. The sixth operating mode includes both the first and second main transformers being engaged, the third main transformer not being engaged, the first sectionalizing switch being open, and the second sectionalizing switch being closed. The seventh operating mode includes both the first and second main transformers being engaged, the third main transformer not being engaged, and both the first and second sectionalizing switches being closed. When the most economical operating mode is the third type of operating mode, the substation rotates between the third operating mode and the fifth operating mode according to the preset cycle.

6. An automatic switching device for backup power supply in a substation, characterized in that, The device includes: The acquisition module is used to acquire the rated parameters, operating parameters, and current operating mode of the substation; the rated parameters refer to the rated current, rated no-load loss, and rated load loss of the secondary side; the operating parameters refer to the current current of the first sectionalizing switch and the current current of the second sectionalizing switch. The processing module is used to process the rated parameters and the operating parameters based on the current operating mode using a preset model to determine the most economical operating mode of the substation; the preset model aims to minimize the total transformer loss. The switching module is used to switch the first main transformer, the second main transformer, the third main transformer, the first sectionalizing switch, and the second sectionalizing switch respectively based on the most economical operating mode if the current operating mode is not the most economical operating mode. Specifically, the first main transformer is switched by switching the first high-voltage switch and the first low-voltage switch; the second main transformer is switched by switching the second high-voltage switch and the second low-voltage switch, or by switching the second high-voltage switch and the third low-voltage switch; and the third main transformer is switched by switching the third high-voltage switch and the fourth low-voltage switch. The processing module is further configured to determine, based on the criterion comparison result, the number of main transformers that need to be put into operation among the first, second, and third main transformers; the criterion comparison result is obtained by comparing the transformer loss in the current mode with the expected transformer loss after switching; the transformer loss in the current mode and the expected transformer loss after switching are obtained by processing the operating parameters using the preset model; if the number of main transformers that need to be put into operation is 3, then the first operating mode is determined as the most economical operating mode; the first operating mode includes the first, second, and third main transformers all being put into operation, and the first sectionalizing switch and the... The second sectionalizing switch is always in the open state. If the number of main transformers to be put into operation is 2, then the second operating mode is determined as the most economical operating mode. The second operating mode includes the first main transformer not being put into operation, the second and third main transformers being put into operation, the first sectionalizing switch being closed, and the second sectionalizing switch being open. If the number of main transformers to be put into operation is 1, then the third operating mode is determined as the most economical operating mode. The third operating mode includes the first and third main transformers not being put into operation, the second main transformer being put into operation, and the first and second sectionalizing switches being closed.

7. The apparatus according to claim 6, characterized in that, The processing module is further configured to process the rated parameters and the operating parameters based on the current operating mode to obtain the transformer loss under the current mode; perform conversion processing on the rated parameters and the operating parameters to obtain the expected transformer loss after switching; process the operating parameters of the substation using the substation's preset model to obtain the transformer loss under the current mode and the expected transformer loss after switching; select a corresponding criterion based on the current operating mode, compare the transformer loss under the current mode and the expected transformer loss after switching, and obtain the criterion comparison result.

8. An automatic switching system for backup power in a substation, comprising a substation and a switching device, wherein the switching device includes a memory and a processor, the memory storing a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the method according to any one of claims 1 to 5.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 5.

10. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 5.

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