Pre-magnetization grid-tie power-up method and system for high voltage transformers

Abstract

The application provides a pre-magnetization grid-connected power-on method and system for a high-voltage transformer. The pre-magnetization grid-connected power-on method for the high-voltage transformer comprises the following steps: arranging a pre-magnetization transformer at a secondary side of a first high-voltage transformer, and connecting a primary side of the pre-magnetization transformer with the secondary side of the first high-voltage transformer; connecting a secondary side of the pre-magnetization transformer with a secondary side of a second high-voltage transformer according to an electrical signal instruction of pre-magnetization grid-connected power-on of the second high-voltage transformer; disconnecting the secondary side of the pre-magnetization transformer from the secondary side of the second high-voltage transformer after pre-magnetization of the second high-voltage transformer is completed; and connecting a primary side of the second high-voltage transformer with a generator. The technical scheme can effectively reduce the excitation current when the high-voltage transformer is pre-magnetized and powered on.

Description

Technical Field

[0001] This application relates to the field of marine power supply technology, and more specifically, to a method and system for pre-magnetizing and energizing a high-voltage transformer. Background Technology

[0002] When a ship's high-voltage transformer has residual magnetism in its core before being connected to the grid, and the direction of this residual magnetic flux is the same as the magnetic flux generated by the transformer's operating voltage, the total magnetic flux far exceeds the core's saturation flux, causing core saturation. This results in a massive inrush current, commonly known as inrush current. Inrush current can cause a decline in power quality, increased grid harmonics, excessive voltage drop leading to tripping of sensitive loads such as motors, and malfunctions in relay protection systems.

[0003] Currently, when large container ships are connected to the grid via high-voltage transformers, multiple generators are used to supply power in parallel to reduce the impact of inrush current. However, if the inrush current generated by the high-voltage transformer is very large, multiple generators need to be run simultaneously, or even all generators on board need to be connected to the grid. This process is cumbersome, and running multiple generators will greatly increase fuel consumption, which is very disadvantageous for ships sailing on long distances. Summary of the Invention

[0004] The purpose of this application is to provide a method for pre-magnetizing and energizing a high-voltage transformer, which can effectively reduce the excitation current when the high-voltage transformer is pre-magnetized and energized, and basically eliminate the phenomenon of excitation inrush current.

[0005] A second objective of this application is to provide a grid connection system capable of implementing the above-described pre-magnetizing and grid connection method for high-voltage transformers.

[0006] In a first aspect, a method for pre-magnetizing and energizing a high-voltage transformer is provided. The high-voltage transformer includes a first high-voltage transformer and a second high-voltage transformer. With the primary side of the first high-voltage transformer connected to a generator and the primary side of the second high-voltage transformer disconnected from the generator, the method for pre-magnetizing and energizing the second high-voltage transformer includes the following steps:

[0007] S1. Set up a pre-magnetized transformer and connect the primary side of the pre-magnetized transformer to the secondary side of the first high-voltage transformer.

[0008] S2. According to the electrical signal command for the pre-magnetization and grid connection of the second high-voltage transformer, connect the secondary side of the pre-magnetization transformer to the secondary side of the second high-voltage transformer.

[0009] S3. After the second high-voltage transformer is pre-magnetized, connect the primary side of the second high-voltage transformer to the generator;

[0010] S4. Disconnect the secondary side of the pre-magnetized transformer from the secondary side of the second high-voltage transformer.

[0011] In one feasible scheme, after the second high-voltage transformer is pre-magnetized and connected to the grid, the following steps are also included: S5, connecting the primary side of the pre-magnetized transformer to the secondary side of the second high-voltage transformer, disconnecting the primary side of the pre-magnetized transformer from the secondary side of the first high-voltage transformer, and disconnecting the primary side of the first high-voltage transformer from the generator.

[0012] According to a second aspect of this application, a pre-magnetized grid-connected power supply system for a high-voltage transformer is also provided, comprising a first high-voltage transformer, a second high-voltage transformer, and a pre-magnetized transformer. The first high-voltage transformer includes a primary side and a secondary side, the second high-voltage transformer includes a primary side and a secondary side, and the pre-magnetized transformer includes a primary side and a secondary side. The primary side of the first high-voltage transformer is connectable to and disconnectable from a generator, and the primary side of the second high-voltage transformer is connectable to and disconnectable from a generator. The primary side of the pre-magnetized transformer is connectable to and disconnectable from the secondary side of the first high-voltage transformer, and the primary side of the pre-magnetized transformer is connectable to and disconnectable from the secondary side of the second high-voltage transformer. The secondary side of the pre-magnetized transformer is connectable to and disconnectable from the secondary side of the first high-voltage transformer, and the secondary side of the pre-magnetized transformer is connectable to and disconnectable from the secondary side of the second high-voltage transformer.

[0013] In one feasible embodiment, a first pre-magnetizing contactor is provided on the circuit connecting the secondary side of the pre-magnetizing transformer to the secondary side of the first high-voltage transformer. The first pre-magnetizing contactor is used to connect or disconnect the connection between the secondary side of the pre-magnetizing transformer and the secondary side of the first high-voltage transformer. A second pre-magnetizing contactor is provided on the circuit connecting the secondary side of the pre-magnetizing transformer to the secondary side of the second high-voltage transformer. The second pre-magnetizing contactor is used to connect or disconnect the connection between the secondary side of the pre-magnetizing transformer and the secondary side of the second high-voltage transformer.

[0014] In one feasible embodiment, the system further includes a first pre-magnetizing switch and a second pre-magnetizing switch; the first pre-magnetizing switch is used to send an electrical signal command for the first high-voltage transformer to be connected to the grid to a first pre-magnetizing contactor, so that the first pre-magnetizing contactor connects the secondary side of the pre-magnetizing transformer to the secondary side of the first high-voltage transformer; the second pre-magnetizing switch is used to send an electrical signal command for the second high-voltage transformer to be connected to the grid to a second pre-magnetizing contactor, so that the second pre-magnetizing contactor connects the secondary side of the pre-magnetizing transformer to the secondary side of the second high-voltage transformer.

[0015] In one feasible embodiment, a first primary-side switch is provided on the circuit connecting the primary side of the first high-voltage transformer to the generator, and the first primary-side switch is used to connect or disconnect the connection between the primary side of the first high-voltage transformer and the generator; a second primary-side switch is provided on the circuit connecting the primary side of the second high-voltage transformer to the generator, and the second primary-side switch is used to connect or disconnect the connection between the primary side of the second high-voltage transformer and the generator.

[0016] In one feasible embodiment, the pre-magnetized and connected power-on system further includes a first busbar, a second busbar, and a bus tie switch; the first busbar is connectable to the secondary side of the first high-voltage transformer, and the second busbar is connectable to the secondary side of the second high-voltage transformer; the first busbar is connectable to the primary side of the pre-magnetized transformer, and the second busbar is connectable to the primary side of the pre-magnetized transformer; the first busbar is connectable to the second busbar via the bus tie switch.

[0017] In one feasible embodiment, a first secondary switch is provided on the circuit between the first busbar and the secondary side of the first high-voltage transformer, the first secondary switch being used to connect or disconnect the connection between the secondary side of the first high-voltage transformer and the first busbar; a second secondary switch is provided on the circuit between the second busbar and the secondary side of the second high-voltage transformer, the second secondary switch being used to connect or disconnect the connection between the secondary side of the second high-voltage transformer and the second busbar.

[0018] In one feasible embodiment, a first electrical switch is provided on the circuit connecting the first busbar to the primary side of the pre-magnetized transformer. The first electrical switch is used to connect or disconnect the connection between the first busbar and the primary side of the pre-magnetized transformer. A second electrical switch is provided on the circuit connecting the second busbar to the primary side of the pre-magnetized transformer. The second electrical switch is used to connect or disconnect the connection between the second busbar and the primary side of the pre-magnetized transformer.

[0019] In one feasible scheme, when the first electrical switch connects the first busbar to the primary side of the pre-magnetized transformer, the second electrical switch simultaneously connects the second busbar to the primary side of the pre-magnetized transformer; when the first electrical switch disconnects the first busbar from the primary side of the pre-magnetized transformer, the second electrical switch simultaneously disconnects the second busbar from the primary side of the pre-magnetized transformer.

[0020] Compared with the prior art, the beneficial effects of this application are as follows:

[0021] 1) In the application of the pre-magnetizing and grid-connected power-on method, the first high-voltage transformer provides power to the pre-magnetizing transformer, enabling the windings of the pre-magnetizing transformer to establish a magnetic field, which provides pre-magnetization for the grid-connected power-on of the second high-voltage transformer. After the second high-voltage transformer establishes a stable magnetic field and completes the pre-magnetization, it is then switched on and grid-connected. After a short transition, it can enter steady-state operation, thereby greatly reducing the excitation current and basically eliminating the inrush current when the second high-voltage transformer is grid-connected.

[0022] 2) If there are multiple second high-voltage transformers, the pre-magnetizing transformer in this application can pre-magnetize multiple second high-voltage transformers, thereby reducing the excitation current when all second high-voltage transformers are connected to the grid. In this way, the excitation current generated when multiple second high-voltage transformers are connected to the grid will not have a significant impact on the power system.

[0023] 3) Because the secondary side of the pre-magnetizing transformer is connected to the secondary side of the second high-voltage transformer, pre-magnetizing the secondary side of the high-voltage transformer is achieved. Compared to the high-cost primary side (high-voltage side) pre-magnetizing, the secondary side (low-voltage side) pre-magnetizing method significantly reduces costs. Furthermore, using the secondary side of the first high-voltage transformer to power the pre-magnetizing transformer is equivalent to using the low-voltage side for power supply. The pre-magnetizing transformer can utilize a small-capacity transformer, thus reducing the impact on the power grid and lowering energy consumption. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a flowchart illustrating a pre-magnetizing and grid-connected power-on method for a high-voltage transformer according to an embodiment of this application;

[0026] Figure 2 This is a flowchart illustrating another method for pre-magnetizing and energizing a high-voltage transformer according to an embodiment of this application;

[0027] Figure 3 This is a schematic diagram of a pre-magnetized and grid-connected power supply system for a high-voltage transformer, according to an embodiment of this application.

[0028] In the diagram: 10, First high-voltage transformer; 20, Second high-voltage transformer; 30, Pre-magnetized transformer; 31, First pre-magnetized contactor; 32, Second pre-magnetized contactor; 40, Generator; 50, First busbar; 60, Second busbar; 70, Bus tie switch; 80, First electrical switch; 90, Second electrical switch; 101-104, Refrigeration transformer. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0030] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0031] According to the first aspect of this application, Figure 1 As shown, a method for pre-magnetizing and connecting a high-voltage transformer to the grid is first provided. The high-voltage transformer includes a first high-voltage transformer and a second high-voltage transformer. With the primary side of the first high-voltage transformer connected to a generator and the primary side of the second high-voltage transformer disconnected from the generator, the method for pre-magnetizing and connecting the second high-voltage transformer to the grid includes the following steps:

[0032] S1. Set up a pre-magnetized transformer and connect the primary side of the pre-magnetized transformer to the secondary side of the first high-voltage transformer.

[0033] S2. According to the electrical signal command for the pre-magnetization and grid connection of the second high-voltage transformer, connect the secondary side of the pre-magnetization transformer to the secondary side of the second high-voltage transformer.

[0034] S3. After the second high-voltage transformer is pre-magnetized, disconnect the secondary side of the pre-magnetized transformer from the secondary side of the second high-voltage transformer.

[0035] S4. Connect the primary side of the second high-voltage transformer to the generator.

[0036] In the above embodiment of the pre-magnetizing and grid-connected power-on method for high-voltage transformers, when the first high-voltage transformer is already grid-connected, the secondary side of the first high-voltage transformer is connected to the primary side of the pre-magnetizing transformer, thereby ensuring that the pre-magnetizing transformer is always energized, allowing the windings of the pre-magnetizing transformer to establish a magnetic field, ready to provide pre-magnetization for the grid connection of other high-voltage transformers. When the second high-voltage transformer needs to be grid-connected, due to the saturation of the core flux and the nonlinearity of the core material, a considerable excitation current is generated when the second high-voltage transformer is connected to the grid under no-load conditions or when the voltage is restored after an external fault is cleared. At this time, the secondary side of the pre-magnetizing transformer is connected to the secondary side of the second high-voltage transformer to achieve pre-magnetization of the secondary side of the second high-voltage transformer. After the second high-voltage transformer establishes a stable magnetic field and completes the pre-magnetization, the connection between the secondary side of the pre-magnetizing transformer and the secondary side of the second high-voltage transformer is disconnected, and the primary side of the second high-voltage transformer can be connected to the generator. Then, the second high-voltage transformer can enter steady-state operation after a short transition, thereby greatly reducing the excitation current and basically eliminating the inrush current when the second high-voltage transformer is grid-connected.

[0037] Meanwhile, if there are multiple second high-voltage transformers, and these transformers are simultaneously connected to the grid, the inrush current will be larger, and the impact on the power system will be greater. However, by connecting the secondary side of the pre-magnetized transformer in this application to the secondary side of these second high-voltage transformers, all the second high-voltage transformers to be connected to the grid can be pre-magnetized, thereby reducing the inrush current when all the second high-voltage transformers are connected to the grid. Thus, the inrush current generated when multiple second high-voltage transformers are connected to the grid will not have a significant impact on the power system.

[0038] Furthermore, since the secondary side of the pre-magnetized transformer is connected to the secondary side of the second high-voltage transformer, pre-magnetization of the secondary side of the high-voltage transformer is achieved. Compared to the high-cost primary-side pre-magnetization, the secondary-side pre-magnetization method significantly reduces costs. Moreover, using the secondary side of the first high-voltage transformer to power the pre-magnetized transformer is equivalent to using low-voltage side power supply. The pre-magnetized transformer can utilize a small-capacity transformer, thus reducing the impact on the power grid and lowering energy consumption.

[0039] In one implementation scheme, such as Figure 2 As shown, after the second high-voltage transformer is pre-magnetized and connected to the power grid, the following steps are also included:

[0040] S5. After step S4, connect the primary side of the pre-magnetized transformer to the secondary side of the second high-voltage transformer, disconnect the primary side of the pre-magnetized transformer from the secondary side of the first high-voltage transformer, and disconnect the primary side of the first high-voltage transformer from the generator.

[0041] Will Figure 2 and Figure 1 Compare with the embodiments, such as Figure 1 The illustrated embodiment involves a pre-magnetized transformer being powered by a single high-voltage transformer (the first high-voltage transformer), while another high-voltage transformer (the second high-voltage transformer) is connected to the grid. For example... Figure 2 The illustrated embodiment achieves switching from the first high-voltage transformer to the second high-voltage transformer without interrupting power supply. Uninterrupted power supply means that the power supply to the load remains continuous, and the power supply to the pre-magnetized transformer is also uninterrupted. Specifically, as shown... Figure 2 As shown, after the second high-voltage transformer is powered on, the method in step S5 ensures that when the first high-voltage transformer is disconnected from the generator and disconnected from the grid, the second high-voltage transformer connected to the grid can continuously supply power to the pre-magnetized transformer, thereby ensuring that the pre-magnetized transformer is always in the grid-connected state, so as to continuously provide pre-magnetization services for other high-voltage transformers and complete the uninterrupted power switching from the first high-voltage transformer to the second high-voltage transformer.

[0042] It should be noted that, Figure 2The first high-voltage transformer and the second high-voltage transformer in the embodiment shown can be used interchangeably. If the first high-voltage transformer is the main high-voltage transformer, the second high-voltage transformer and the first high-voltage transformer should have the same performance and the same parameters, and they can be used interchangeably. Figure 1 The embodiment shown does not involve switching between the second high-voltage transformer and the first high-voltage transformer, therefore Figure 1 The second high-voltage transformer can be either a transformer with the same parameters and performance as the first high-voltage transformer, used in daily life, or a refrigeration transformer used for other purposes.

[0043] According to the second aspect of this application, such as Figure 3 As shown, a pre-magnetizing and grid-connected power supply system for high-voltage transformers is also provided, which can realize the pre-magnetizing and grid-connected power supply method for high-voltage transformers in the above scheme.

[0044] Among them, such as Figure 3 As shown, a pre-magnetizing and grid-connected power supply system for high-voltage transformers includes a first high-voltage transformer 10, a second high-voltage transformer 20, and a pre-magnetizing transformer 30. The first high-voltage transformer 10 includes a primary side and a secondary side; the second high-voltage transformer 20 includes a primary side and a secondary side; and the pre-magnetizing transformer 30 includes a primary side and a secondary side. The primary side of the first high-voltage transformer 10 and the primary side of the second high-voltage transformer 20 are connectable to and disconnectable from the generator 40. The primary side of the pre-magnetizing transformer 30 is connectable to and disconnectable from the secondary side of the first high-voltage transformer 10, and the secondary side of the pre-magnetizing transformer 30 is connectable to and disconnectable from the secondary side of the second high-voltage transformer 20.

[0045] Figure 3 The above-described embodiments shown implement Figure 1 The method shown refers to the pre-magnetization and grid connection of the second high-voltage transformer 20 when the primary side of the first high-voltage transformer 10 is connected to the generator 40 and the primary side of the second high-voltage transformer 20 is disconnected from the generator 40. The steps are as follows:

[0046] The first step is to connect the primary side of the pre-magnetized transformer 30 to the secondary side of the first high-voltage transformer 10 to enable power supply to the pre-magnetized transformer 30.

[0047] The second step is to connect the secondary side of the pre-magnetizing transformer 30 to the secondary side of the second high-voltage transformer 20 according to the electrical signal command for the pre-magnetizing and grid-connected power supply of the second high-voltage transformer 20, so that the second high-voltage transformer 20 can be charged through the pre-magnetizing transformer 30.

[0048] The third step is to connect the primary side of the second high-voltage transformer 20 to the generator 40 after the second high-voltage transformer 20 has been pre-magnetized, thereby turning on the power supply of the second high-voltage transformer 20.

[0049] Fourth step: Disconnect the secondary side of the pre-magnetized transformer 30 from the secondary side of the second high-voltage transformer 20. This disconnection should be done as quickly as possible when the second high-voltage transformer 20 is switched on, so as to minimize the adverse effects of the pre-magnetized transformer 30 on the second high-voltage transformer 20 after it is powered on.

[0050] Figure 3 The above-described embodiments shown implement Figure 2 The method shown involves switching to the pre-magnetized and connected power supply of the second high-voltage transformer 20 when the primary side of the first high-voltage transformer 10 is connected to the generator 40 and the primary side of the second high-voltage transformer 20 is disconnected from the generator 40, and disconnecting the first daytime transformer 10. In addition to the first to fourth steps described above, the method also includes the following steps:

[0051] Fifth, connect the primary side of the pre-magnetizing transformer 30 to the secondary side of the second high-voltage transformer 20, which is equivalent to using the second high-voltage transformer 20 to supply power to the pre-magnetizing transformer 30. Then disconnect the primary side of the pre-magnetizing transformer 30 from the secondary side of the first high-voltage transformer 10, which is equivalent to disconnecting the first high-voltage transformer 10 from supplying power to the pre-magnetizing transformer 30. Finally, disconnect the primary side of the first high-voltage transformer 10 from the generator 40, thereby shutting down the first high-voltage transformer 10.

[0052] In one implementation scheme, such as Figure 3 As shown, a first pre-magnetizing contactor 31 is installed on the circuit connecting the secondary side of the pre-magnetizing transformer 30 and the secondary side of the first high-voltage transformer 10, i.e. Figure 3 In section KM1, the first pre-magnetizing contactor 31 is used to connect or disconnect the secondary side of the pre-magnetizing transformer 30 from the secondary side of the first high-voltage transformer 10. A second pre-magnetizing contactor 32, as shown in section KM2, is installed on the circuit connecting the secondary side of the pre-magnetizing transformer 30 to the secondary side of the second high-voltage transformer 20. The second pre-magnetizing contactor 32 is used to connect or disconnect the secondary side of the pre-magnetizing transformer 30 from the secondary side of the second high-voltage transformer 20.

[0053] The first pre-magnetizing contactor 31 and the second pre-magnetizing contactor 32 in the above scheme facilitate the control of magnetization of the high-voltage transformer. In addition to KM1 and KM2, KM3, KM4, KM5, KM6, etc., can also be set, which respectively control the secondary side of the pre-magnetizing transformer 30 and... Figure 3 The secondary windings of the four refrigeration transformers (101, 102, 103, 104) are connected or disconnected. This affects the operation of... Figure 1The method described above allows the four refrigerated transformers (101, 102, 103, 104) to be energized in the same way as the second high-voltage transformer 20. Multiple pre-magnetized contactors are installed to facilitate the pre-magnetization and switching control of the multiple high-voltage transformers.

[0054] In one embodiment, a first pre-magnetizing switch and a second pre-magnetizing switch are further included. The first pre-magnetizing switch is used to send an electrical signal command for the first high-voltage transformer 10 to be connected to the grid to a first pre-magnetizing contactor, so that the first pre-magnetizing contactor 31 connects the secondary side of the pre-magnetizing transformer 30 to the secondary side of the first high-voltage transformer 10. The second pre-magnetizing switch is used to send an electrical signal command for the second high-voltage transformer 20 to be connected to the grid to a second pre-magnetizing contactor, so that the second pre-magnetizing contactor 32 connects the secondary side of the pre-magnetizing transformer 30 to the secondary side of the second high-voltage transformer 20.

[0055] The first and second pre-magnetizing switches can be physical buttons, virtual buttons on a control screen, or preset delayed electrical signals. Their purpose is to send electrical signal commands to switches such as KM1 and KM2, thereby controlling the corresponding pre-magnetizing contactors to close and pre-magnetize the corresponding high-voltage transformers, simplifying operation. The pre-magnetizing switches can be installed away from high-voltage areas, thus reducing operational risks for workers.

[0056] In one implementation scheme, such as Figure 3 As shown, a first primary-side switch HR1 is provided on the circuit connecting the primary side of the first high-voltage transformer 10 and the generator 40. The first primary-side switch HR1 is used to connect or disconnect the connection between the primary side of the first high-voltage transformer 10 and the generator 40. A second primary-side switch HR2 is provided on the circuit connecting the primary side of the second high-voltage transformer 20 and the generator 40. The second primary-side switch HR2 is used to connect or disconnect the connection between the primary side of the second high-voltage transformer 20 and the generator 40.

[0057] In one embodiment, the pre-magnetized grid-connected power supply system further includes a first busbar 50, a second busbar 60, and a bus tie switch 70. The first busbar 50 is connectable to the secondary side of the first high-voltage transformer 10, and the second busbar 60 is connectable to the secondary side of the second high-voltage transformer 20. The first busbar 50 is connectable to the primary side of the pre-magnetized transformer 30, and the second busbar 60 is connectable to the primary side of the pre-magnetized transformer 30. The first busbar 50 is connected to the second busbar 60 via the bus tie switch 70.

[0058] It should be noted that the bus tie switch 70 of the first busbar 50 and the second busbar 60 is normally closed by default, that is... Figure 3The LBT in the circuit is in a closed state by default, which means that the first busbar 50 and the second busbar 60 are actually one busbar. The second high-voltage transformer 20 and the secondary side of the first high-voltage transformer 10 are connected to the busbar, thereby connecting to the power supply. At the same time, some electrical loads can be connected to the busbar to obtain power.

[0059] Meanwhile, different loads are connected to the first busbar 50 and the second busbar 60, and the first busbar 50 and the second busbar 60 are connected to the first high-voltage transformer 10 and the second high-voltage transformer 20, respectively. If only one of the first high-voltage transformer 10 or the second high-voltage transformer 20 is energized, as long as the bus tie switch 70 is closed, the loads on the entire busbar (first busbar 50 and second busbar 60) can continue to operate without power. Furthermore, if the first high-voltage transformer 10 is energized while the second high-voltage transformer 20 is de-energized, and if the loads on the second busbar 60 require maintenance or the connection of new equipment, the bus tie switch 70 can be temporarily opened to disconnect the first busbar 50 and the second busbar 60, thereby facilitating maintenance operations on the loads connected to the second busbar 60.

[0060] In one embodiment, a first secondary switch LR1 is provided on the circuit between the first busbar 50 and the secondary side of the first high-voltage transformer 10. The first secondary switch LR1 is used to connect or disconnect the connection between the secondary side of the first high-voltage transformer 10 and the first busbar 50. A second secondary switch LR2 is provided on the circuit between the second busbar 60 and the secondary side of the second high-voltage transformer 20. The second secondary switch LR2 is used to connect or disconnect the connection between the secondary side of the second high-voltage transformer 20 and the second busbar 60.

[0061] In one implementation scheme, such as Figure 3 As shown, a first electrical switch 80 is installed on the circuit connecting the first busbar 50 and the primary side of the pre-magnetized transformer 30, i.e. Figure 3 In the MCCB1 circuit, the first electrical switch 80 is used to connect or disconnect the connection between the first busbar 50 and the primary side of the pre-magnetized transformer 30. A second electrical switch 90 is provided on the circuit connecting the second busbar 60 and the primary side of the pre-magnetized transformer 30. Figure 3 In the MCCB2 section, the second electrical switch 90 is used to connect or disconnect the second busbar 60 from the primary side of the pre-magnetizing transformer 30. When the pre-magnetizing transformer 30 is not needed, the first electrical switch 80 and the second electrical switch 90 are used to flexibly disconnect the pre-magnetizing transformer 30.

[0062] In one implementation scheme, such as Figure 3As shown, when the first electrical switch 80 connects the first busbar 50 and the primary side of the pre-magnetized transformer 30, the second electrical switch 90 simultaneously connects the second busbar 60 and the primary side of the pre-magnetized transformer 30; when the first electrical switch 80 disconnects the first busbar 50 and the primary side of the pre-magnetized transformer 30, the second electrical switch 90 simultaneously disconnects the second busbar 60 and the primary side of the pre-magnetized transformer 30. The above scheme represents... Figure 3 MCCB1 and Figure 3 The MCCB2 in the circuit is a linkage mode that allows both MCCB1 and MCCB2 to open or close simultaneously. Therefore, when the bus tie switch 70 is in the open state, because MCCB1 and MCCB2 are open or closed simultaneously, the pre-magnetized transformer 30 can maintain uninterrupted operation as long as either the first bus 50 or the second bus 60 is energized.

[0063] In another embodiment, when the first electrical switch 80 connects the first busbar 50 and the primary side of the pre-magnetized transformer 30, the second electrical switch 90 simultaneously disconnects the second busbar 60 and the primary side of the pre-magnetized transformer 30; when the first electrical switch 80 disconnects the first busbar 50 and the primary side of the pre-magnetized transformer 30, the second electrical switch 90 simultaneously connects the second busbar 60 and the primary side of the pre-magnetized transformer 30. The above-described scheme represents... Figure 3 MCCB1 and Figure 3 The MCCB2 in this circuit is a linkage mode where one busbar is open while the other is closed simultaneously. When the bus tie switch 70 is in the open state, if the first busbar 50 experiences a situation including but not limited to leakage or short circuit, the MCCB2 is closed to connect the second busbar 60, while the MCCB1 is simultaneously disconnected from the first busbar 50, thereby disconnecting the circuit from the faulty first busbar 50 to ensure that the remaining circuits can still operate normally.

[0064] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A pre-magnetized grid-connected power supply system for a high-voltage transformer, comprising a first high-voltage transformer (10), a second high-voltage transformer (20), and a pre-magnetized transformer (30), wherein the first high-voltage transformer (10) comprises a primary side and a secondary side, the second high-voltage transformer (20) comprises a primary side and a secondary side, and the pre-magnetized transformer (30) comprises a primary side and a secondary side, characterized in that, The primary side of the first high-voltage transformer (10) can be switched on and off with the generator (40), and the primary side of the second high-voltage transformer (20) can be switched on and off with the generator (40); The primary side of the pre-magnetized transformer (30) can be switched on and off with the secondary side of the first high-voltage transformer (10), and the primary side of the pre-magnetized transformer (30) can be switched on and off with the secondary side of the second high-voltage transformer (20). The secondary side of the pre-magnetized transformer (30) can be switched on and off with the secondary side of the first high-voltage transformer (10), and the secondary side of the pre-magnetized transformer (30) can be switched on and off with the secondary side of the second high-voltage transformer (20). The pre-magnetized and connected power-on system also includes a first busbar (50), a second busbar (60), and a bus tie switch (70). The first busbar (50) is connected to the secondary side of the first high-voltage transformer (10) in a switchable manner, and the second busbar (60) is connected to the secondary side of the second high-voltage transformer (20) in a switchable manner; The first busbar (50) can be switched on and off with the primary side of the pre-magnetized transformer (30), and the second busbar (60) can be switched on and off with the primary side of the pre-magnetized transformer (30). The first busbar (50) is connected to the second busbar (60) via the bus tie switch (70); A first electrical switch (80) is provided on the circuit connecting the first busbar (50) and the primary side of the pre-magnetized transformer (30). The first electrical switch (80) is used to connect or disconnect the connection between the first busbar (50) and the primary side of the pre-magnetized transformer (30). A second electrical switch (90) is provided on the circuit connecting the second busbar (60) and the primary side of the pre-magnetized transformer (30). The second electrical switch (90) is used to connect or disconnect the connection between the second busbar (60) and the primary side of the pre-magnetized transformer (30). The pre-magnetized grid-connected power supply system is configured such that, when the primary side of the first high-voltage transformer (10) is connected to the generator (40) and the primary side of the second high-voltage transformer (20) is disconnected from the generator (40), the primary side of the pre-magnetized transformer (30) is connected to the secondary side of the first high-voltage transformer (10) via the first bus (50), and the secondary side of the pre-magnetized transformer (30) is connected to the secondary side of the second high-voltage transformer (20) to pre-magnetize the secondary side of the second high-voltage transformer (20). After the second high-voltage transformer (20) is pre-magnetized, the primary side of the second high-voltage transformer (20) is connected to the generator (40), the secondary side of the pre-magnetized transformer (30) is disconnected from the secondary side of the second high-voltage transformer (20), and the primary side of the pre-magnetized transformer (30) is connected to the secondary side of the second high-voltage transformer (20) via the second bus (60), the primary side of the pre-magnetized transformer (30) is disconnected from the secondary side of the first high-voltage transformer (10), and the primary side of the first high-voltage transformer (10) is disconnected from the generator (40).

2. The pre-magnetizing and grid-connected power supply system for high-voltage transformers according to claim 1, characterized in that, A first pre-magnetizing contactor (31) is provided on the circuit connecting the secondary side of the pre-magnetizing transformer (30) and the secondary side of the first high-voltage transformer (10). The first pre-magnetizing contactor (31) is used to connect or disconnect the connection between the secondary side of the pre-magnetizing transformer (30) and the secondary side of the first high-voltage transformer (10). A second pre-magnetizing contactor (32) is provided on the circuit connecting the secondary side of the pre-magnetizing transformer (30) and the secondary side of the second high-voltage transformer (20). The second pre-magnetizing contactor (32) is used to connect or disconnect the connection between the secondary side of the pre-magnetizing transformer (30) and the secondary side of the second high-voltage transformer (20).

3. The pre-magnetizing and grid-connected power supply system for high-voltage transformers according to claim 2, characterized in that, It also includes a first pre-magnetizing switch and a second pre-magnetizing switch; The first pre-magnetizing switch is used to send the electrical signal command for the first high-voltage transformer (10) to be connected to the grid to the first pre-magnetizing contactor, so that the first pre-magnetizing contactor (31) connects the secondary side of the pre-magnetizing transformer (30) to the secondary side of the first high-voltage transformer (10). The second pre-magnetizing switch is used to send an electrical signal command for the second high-voltage transformer (20) to be connected to the grid to the second pre-magnetizing contactor, so that the second pre-magnetizing contactor (32) connects the secondary side of the pre-magnetizing transformer (30) to the secondary side of the second high-voltage transformer (20).

4. The pre-magnetizing and grid-connected power supply system for high-voltage transformers according to claim 1, characterized in that, A first primary-side switch is provided on the circuit connecting the primary side of the first high-voltage transformer (10) and the generator (40). The first primary-side switch is used to connect or disconnect the connection between the primary side of the first high-voltage transformer (10) and the generator (40). A second primary-side switch is provided on the circuit connecting the primary side of the second high-voltage transformer (20) and the generator (40). The second primary-side switch is used to connect or disconnect the connection between the primary side of the second high-voltage transformer (20) and the generator (40).

5. The pre-magnetizing and grid-connected power supply system for a high-voltage transformer according to claim 1, characterized in that, A first secondary switch is provided on the circuit between the first busbar (50) and the secondary side of the first high-voltage transformer (10). The first secondary switch is used to connect or disconnect the connection between the secondary side of the first high-voltage transformer (10) and the first busbar (50). A second secondary switch is provided on the circuit between the second busbar (60) and the secondary side of the second high-voltage transformer (20). The second secondary switch is used to connect or disconnect the connection between the secondary side of the second high-voltage transformer (20) and the second busbar (60).

6. The pre-magnetizing and grid-connected power supply system for a high-voltage transformer according to claim 1, characterized in that, When the first electrical switch (80) connects the first busbar (50) and the primary side of the pre-magnetized transformer (30), the second electrical switch (90) simultaneously connects the second busbar (60) and the primary side of the pre-magnetized transformer (30); when the first electrical switch (80) disconnects the first busbar (50) and the primary side of the pre-magnetized transformer (30), the second electrical switch (90) simultaneously disconnects the second busbar (60) and the primary side of the pre-magnetized transformer (30).

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