Grounding conversion method and system of addressing cascade direct current power transmission system, storage medium, electronic equipment and computer program product

Abstract

The invention discloses a grounding conversion method and system of an addressing cascade direct current power transmission system, a storage medium, electronic equipment and a computer program product. The grounding conversion method of the addressing cascade direct current power transmission system comprises the following steps: receiving a first instruction from a first converter station; determining a first current value of a first change-over switch of the second converter station according to the first instruction; if it is determined that the first current value meets a first preset condition, sending a second instruction to a third converter station, so that the third converter station closes a grounding switch of the third converter station in response to the second instruction; in response to a third instruction from a third converter station, collecting a second current value of the first change-over switch; and if it is determined that the second current value satisfies a second preset condition, sending a fourth instruction to the second converter station, so that the second converter station turns off a second change-over switch of the second converter station in response to the fourth instruction.

Description

Technical Field

[0001] The present application relates to the technical field of direct current transmission systems, and in particular to a grounding conversion method, system, storage medium, electronic device and computer program product for a distributed cascade direct current transmission system. Background Art

[0002] Figure 1 The topological structure diagram of the distributed cascaded DC transmission system is shown in Figure 1. Figure 1 , the sub-address cascaded DC is a typical series connection mode of multi-terminal DC. The sub-address cascaded DC transmission system includes two poles, namely the first pole and the second pole. The high-voltage converters of the first pole and the second pole are arranged at the high-end converter station, and the low-voltage converters of the first pole and the second pole are arranged at the low-end converter station. The high-end converter station and the low-end converter station are connected by a DC line.

[0003] exist Figure 1 In the system shown, grounding pole lines are configured on both the high-end converter station side and the low-end converter station side. The DC current on the high-voltage converter station side can be grounded through the grounding pole line on the low-end converter station side, or through the grounding pole line on the high-end converter station side. The two grounding methods can be directly converted, thereby improving the availability and reliability of the DC transmission system. The above wiring method is currently used in the sub-address cascaded ultra-high voltage DC transmission system under construction in China.

[0004] However, the inventors of the present application have discovered that, in certain operating modes of the sub-address cascaded DC transmission system (for example, operating in a metallic return line mode), during the process of the DC current sending end being converted from grounding through the high-end converter station grounding electrode line to grounding through the low-end converter station grounding electrode, the DC current flowing through the conversion switch in the transfer branch may not reach the set protection setting, causing the control system of the sub-address cascaded DC transmission system to be unable to recognize whether the transfer branch is effectively established, thereby causing the conversion failure. Summary of the invention

[0005] According to one aspect of the present application, a grounding conversion method for a divided-address cascaded DC transmission system is provided, the grounding conversion method comprising: receiving a first instruction from a first converter station; determining a first current value of a first conversion switch of a second converter station according to the first instruction; if it is determined that the first current value satisfies a first preset condition, sending a second instruction to a third converter station, so that the third converter station closes the grounding switch of the third converter station in response to the second instruction; in response to a third instruction from the third converter station, collecting a second current value of the first conversion switch; if it is determined that the second current value satisfies a second preset condition, sending a fourth instruction to the second converter station, so that the second converter station disconnects the second conversion switch of the second converter station in response to the fourth instruction.

[0006] According to one aspect of the present application, a grounding conversion method for a split-address cascaded DC transmission system is provided, wherein the grounding switch of the third converter station comprises a first grounding switch and a second grounding switch, the grounding device of the first grounding switch is arranged in the area of ​​the third converter station, and the grounding device of the second grounding switch is arranged outside the area of ​​the third converter station; the grounding conversion method comprises: the grounding conversion method comprises: collecting a third current value of the converter of the second converter station; determining a first current value of a first conversion switch of the second converter station according to the third current value; receiving a first instruction from the first converter station; determining according to the first instruction that the first current value satisfies a first preset condition, then sending a second instruction to the third converter station so that the third converter station closes the second grounding switch in response to the second instruction; sending a sixth instruction to the second converter station in response to the third instruction from the third converter station so that the second converter station closes the first conversion switch in response to the sixth instruction; collecting a second current value of the first conversion switch; determining that the second current value satisfies a second preset condition, then sending a fourth instruction to the second converter station so that the second converter station disconnects the second conversion switch of the second converter station in response to the fourth instruction.

[0007] According to one aspect of the present application, a grounding conversion system of a divided-address cascaded DC transmission system is also provided, the grounding conversion system comprising a processing module and a collection module; the processing module receives a first instruction from a first converter station; the collection module receives the first instruction transmitted by the processing module, and collects a first current value of a first conversion switch of a second converter station according to the first instruction; the processing module also receives and determines the first current value, and if it is determined that the first current value meets a first preset condition, a second instruction is sent to a third converter station, so that the third converter station closes the grounding switch of the third converter station in response to the second instruction, and the processing module receives a third instruction from the third converter station; the collection module receives the third instruction transmitted by the processing module, and collects a second current value of the first conversion switch according to the third instruction; the processing module also determines that the second current value meets the second preset condition, and a fourth instruction is sent to the second converter station, so that the second converter station disconnects the second conversion switch of the second converter station in response to the fourth instruction.

[0008] According to one aspect of the present application, a non-volatile computer-readable storage medium is further provided, on which a computer program is stored. When the computer program is executed by a processor, the grounding conversion method of the split-address cascaded DC transmission system as described above can be implemented.

[0009] According to one aspect of the present application, there is also provided an electronic device, comprising: one or more processors; a storage device for storing one or more programs, wherein when the one or more programs are executed by the one or more processors, the one or more processors are enabled to implement the grounding conversion method of the distributed cascaded DC transmission system as described above.

[0010] According to one aspect of the present application, a computer program product is also provided, comprising: a computer program stored on a computer-readable storage medium; the computer program comprises program instructions, and when the program instructions are executed by a computer, the computer executes the grounding conversion method of the split-address cascaded DC transmission system as described above.

[0011] According to one aspect of the present application, a non-volatile computer-readable storage medium is further provided, on which a computer program is stored. When the computer program is executed by a processor, the grounding conversion method of the split-address cascaded DC transmission system as described above can be implemented.

[0012] According to one aspect of the present application, there is also provided an electronic device, comprising: one or more processors; a storage device for storing one or more programs, wherein when the one or more programs are executed by the one or more processors, the one or more processors are enabled to implement the grounding conversion method of the distributed cascaded DC transmission system as described above.

[0013] According to one aspect of the present application, a computer program product is also provided, comprising: a computer program stored on a computer-readable storage medium; the computer program comprises program instructions, and when the program instructions are executed by a computer, the computer executes the grounding conversion method of the split-address cascaded DC transmission system as described above.

[0014] Through the above-mentioned technical solution, when the present application determines that the first current value of the first conversion switch meets the first preset condition, the grounding switch of the third converter station is closed to increase the current value flowing through the first conversion switch, so that the computer system can effectively identify the effective establishment of the transfer branch. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0016] Figure 1 A schematic diagram of the topological structure of the sub-address cascaded DC transmission system is shown;

[0017] Figure 2 A schematic diagram showing the topological structure of the split-address cascaded DC transmission system with grounding pole conversion in the metallic return state;

[0018] Figure 3 A schematic flow chart showing a grounding conversion method 1000 for a split-address cascaded DC power transmission system according to an embodiment of the present application is shown;

[0019] Figure 4A schematic flow chart showing a grounding conversion method 2000 for a split-address cascaded DC power transmission system according to an embodiment of the present application;

[0020] Figure 5 A schematic diagram of a process of step S230 according to an embodiment of the present application is shown;

[0021] Figure 6 Another schematic diagram of the process of step S230 according to an embodiment of the present application is shown;

[0022] Figure 7 Another schematic diagram of the process of step S230 according to an embodiment of the present application is shown;

[0023] Figure 8 Another schematic diagram of the process of step S230 according to an embodiment of the present application is shown;

[0024] Fig. 9 A schematic diagram showing the process of step S260 according to an embodiment of the present application is shown;

[0025] Fig.10 A schematic flow chart showing a grounding conversion method 3000 for a split-address cascaded DC power transmission system according to an embodiment of the present application is shown;

[0026] Fig.11 A schematic diagram showing the process of step S350 according to an embodiment of the present application is shown;

[0027] Fig.12 A schematic structural diagram of a grounding conversion system 4000 of a distributed cascaded DC power transmission system according to an embodiment of the present application is shown.

[0028] Reference numerals:

[0029] Sending end 1; receiving end 2; first DC line 3.

[0030] A first converter station 11; a second converter station 12; a second DC line 13; a first conversion switch 14; a second conversion switch 15; a first grounding electrode line 16; a second grounding electrode line 17; a low-voltage converter 18; and a high-voltage converter 19.

[0031] The third converter station 21 ; the grounding switch 22 ; the first grounding switch 23 ; the second grounding switch 24 ; and the receiving-end converter 25 .

[0032] A first DC line 31 of a first pole; and a first DC line 32 of a second pole.

[0033] Ground transfer system 4000 for a split-address cascaded DC transmission system.

[0034] Processing module 4100; Collection module 4200. DETAILED DESCRIPTION

[0035] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this application will be comprehensive and complete and will fully convey the concepts of the example embodiments to those skilled in the art. The same reference numerals in the figures represent the same or similar parts, and thus their repeated description will be omitted.

[0036] The described features, structures or characteristics may be combined in one or more embodiments in any suitable manner. In the following description, many specific details are provided to provide a full understanding of the embodiments of the present disclosure. However, those skilled in the art will appreciate that the technical solutions of the present disclosure may be practiced without one or more of these specific details, or other modes, components, materials, devices, etc. may be adopted. In these cases, known structures, methods, devices, implementations, materials or operations will not be shown or described in detail.

[0037] In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units that are not listed, or may optionally include other steps or units that are inherent to these processes, methods, products or devices.

[0038] The terms "first", "second" and the like in the specification and claims of this application and the above drawings are used to distinguish different objects rather than to describe a specific order.

[0039] The following is a clear and complete description of the technical solution of the present application in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0040] According to one aspect of the present application, a grounding conversion method 1000 of a split-address cascaded DC transmission system is provided. Figure 3 The grounding conversion method 1000 includes steps S110 to S150. Exemplarily, the grounding conversion method 1000 may be executed by a computer system, and the computer system may be a client device (such as a host, etc.) with data processing capabilities.

[0041] Figure 1 The topological structure diagram of the distributed cascaded DC transmission system is shown in Figure 1. Figure 1The sending end 1 is a distributed cascade DC layout, and the receiving end 2 is a conventional UHV DC layout. The low-voltage converter of the sending end 1 is set at the first converter station 11, that is, the low-end converter station. The first converter station 11 is equipped with a low-voltage converter 18 and an AC filter and a DC filter (Direct Current Filters, DCF); the high-voltage converter 19 of the sending end 1 is set at the second converter station 12, that is, the high-end converter station. The second converter station 12 is equipped with a high-voltage converter 19 and an AC filter and a DC filter (DCF).

[0042] The first converter station 11 and the second converter station 12 are connected by a DC line 13. The first converter station 11 and the second converter station 12 are respectively equipped with a pole bus area and a bipolar bus area DC field. The first converter station 11 and the second converter station 12 are connected to a common grounding electrode through their respective grounding electrode leads. The converter station at the receiving end 2 is the third converter station 21, and the third converter station 12 is provided with a receiving end converter 25, an AC filter and a DC filter (DCF).

[0043] The third converter station 21 is connected to the second converter station 12 through the first DC line 3. The first pole 4 of the split-address cascade DC transmission system is provided with a first DC line 31 of the first pole, and the DC current flows from the second converter station 12 to the third converter station 21 through the first DC line 31 of the first pole. The second pole 5 of the split-address cascade DC transmission system is provided with a first DC line 32 of the second pole. The DC current flows from the third converter station 21 to the second converter station 12 through the first DC line 32 of the second pole, thereby forming a DC current transmission loop.

[0044] Figure 2 A schematic diagram showing the topology of a split-address cascaded DC transmission system with grounding pole conversion in a metallic return line state. Figure 2 exist Figure 1 Equipment and areas that are not involved in operation or are unimportant are omitted.

[0045] See also Figure 2 The second converter station 12 may include a first conversion switch 14 and a second conversion switch 15. The first conversion switch 14 is connected to the first converter station 11 through a DC line 13. The first converter station 11 is connected to a first grounding electrode line 16. The second conversion switch 15 is connected to a second grounding electrode line 17.

[0046] When the valve group of the first converter station 11 at the sending end 1 is not in operation and is in a bypass state, and the valve group of the second converter station 12 at the sending end 11 is in operation, the DC current of the second converter station 12 can be grounded through the grounding electrode line on this side, that is, connected to the grounding device through the second conversion switch 15-second grounding electrode line 17; the DC current of the second converter station 12 can also be grounded through the grounding electrode line of the first converter station 11, that is, connected to the grounding device through the first conversion switch 14-second DC line 13-first converter station 11-first grounding electrode line 16.

[0047] When the valve group of the first converter station 11 at the sending end 1 is bypassed and the DC current of the second converter station 12 is converted from grounding via the grounding electrode line on this side to grounding via the grounding electrode line through the first converter station 11, there will be two branches in parallel. After the DC current flows into the second converter station 12 at the sending end 1 via the first DC line 32 of the second pole, it flows into the high-voltage converter 19 of the second converter station 12 via the first branch: the second grounding electrode line 17-the first grounding electrode line 16-the first converter station 11-the second DC line 13-the first conversion switch 14; at the same time, the DC current flows into the high-voltage converter 19 of the second converter station 12 via the second branch: the second conversion switch 15.

[0048] Since both the grounding electrode line and the DC line have resistance, and the resistance of the second branch is basically 0, the second branch can share all the DC current, while the current flowing through the first branch is basically 0, resulting in the current flowing through the first conversion switch 18 being less than the protection setting value set therein, causing the control system of the sub-address cascaded DC transmission system to be unable to identify whether the transfer branch (first grounding electrode line 16-first converter station 11-second DC line 13-first conversion switch 14) is effectively established, thereby not allowing the second conversion switch 15 to be disconnected, resulting in conversion failure.

[0049] In step S110, a first instruction from a first converter station is received.

[0050] According to an example embodiment, the first instruction may be instruction information for putting the first converter station into operation. The first instruction may be generated and sent by the first converter station.

[0051] For example, in step S110, the computer system receives a first instruction from the first converter station. The grounding mode of the second converter station needs to be converted from grounding through the grounding electrode line on the local side to grounding through the grounding electrode line of the first converter station. For example, see Figure 2 The grounding method of the second converter station 12 needs to be converted from being connected to the grounding device through the second conversion switch 15-the second grounding electrode line 17 to being connected to the grounding device through the first conversion switch 14-the second DC line 13-the first converter station 11-the first grounding electrode line 16.

[0052] In step S120, a first current value of a first switch of the second converter station is determined according to the first instruction.

[0053] According to an example embodiment, after receiving the first instruction, the computer system closes the first transfer switch of the second converter station in response to the first instruction. After the first transfer switch is closed, the computer system establishes a grounding transfer branch of the second converter station, that is, establishes a branch in which the second converter station is grounded through the grounding electrode line of the first converter station.

[0054] According to the first instruction, the computer system can collect the first current value flowing through the first conversion switch by means of an electronic current transformer or an optical current transformer. For example, in step S120, see Figure 2 The computer system can collect the first current value of the first conversion switch 14 by means of an electronic current transformer, which is 10 amperes.

[0055] In step S130, if it is determined that the first current value satisfies the first preset condition, a second instruction is sent to the third converter station, so that the third converter station closes the grounding switch of the third converter station in response to the second instruction.

[0056] According to an example embodiment, the first preset condition may be that the first current value of the first conversion switch is less than a protection value of the first conversion switch. The protection value of the first conversion switch may be determined according to a zero drift value of a current measurement point next to the first conversion switch.

[0057] According to an example embodiment, the second instruction may be instruction information for closing the grounding switch of the third converter station. The third converter station closes the grounding switch of the third converter station in response to the second instruction, and after the DC current flows into the grounding device of the second converter station through the grounding device of the third converter station, the DC current flows into the high-voltage converter of the second converter station through the grounding electrode line of the second converter station and the second conversion switch; the DC current also flows into the high-voltage converter of the second converter station through the grounding electrode line of the first converter station, the first converter station, the DC line between the first converter station and the second converter station, and the first conversion switch.

[0058] For example, in step S130, see Figure 2 , the first current value is 10 amperes, the protection value of the first conversion switch 14 is 20 amperes, and the computer system determines that the first current value is less than the protection value of the first conversion switch. Then the computer system sends a second instruction to the third converter station 21, so that the third converter station 21 closes the grounding switch 22 of the third converter station 21 in response to the second instruction.

[0059] See also Figure 2The third converter station 21 closes the grounding switch 22 of the third converter station 21 in response to the second instruction. The DC current flows into the grounding device of the second converter station 12 through the grounding device of the third converter station 21, and then flows into the high-voltage converter 19 of the second converter station 12 through the third branch: the second grounding electrode line 17-the second conversion switch 15; the DC current also flows into the high-voltage converter 19 of the second converter station through the fourth branch: the first grounding electrode line 16-the first converter station 11-the second DC line 13-the first conversion switch 14.

[0060] See also Figure 2 , the third branch is connected in parallel with the fourth branch. The fourth branch is increased in resistance value relative to the second branch by adding a second grounding electrode line 17 relative to the second branch. The third branch is reduced in resistance value relative to the first branch by reducing a second grounding electrode line 17 relative to the first branch. Thus, the current value flowing through the first conversion switch 14 is increased.

[0061] In step S140, in response to a third instruction from the third converter station, a second current value of the first transfer switch is collected.

[0062] According to an example embodiment, the third instruction may be feedback instruction information generated after the third converter station closes the grounding switch.

[0063] According to an exemplary embodiment, after receiving the third instruction, the computer system may collect the current value flowing through the first conversion switch by means of an electronic current transformer or an optical current transformer in response to the third instruction. For example, in step S140, see Figure 2 The computer system can collect the second current value of the first conversion switch 14 by means of an electronic current transformer, which is 1500 amperes.

[0064] In step S150, if it is determined that the second current value satisfies the second preset condition, a fourth instruction is sent to the second converter station, so that the second converter station disconnects the second transfer switch of the second converter station in response to the fourth instruction.

[0065] According to an example embodiment, the second preset condition may be that the second current value of the first conversion switch is greater than or equal to a protection value of the first conversion switch.

[0066] The fourth instruction may be instruction information for disconnecting the second conversion switch generated when the computer system determines that the second current value satisfies the second preset condition. After the second conversion switch is disconnected, the computer system disconnects the branch connected to the second converter station through the grounding electrode line on its side, thereby completing the conversion process of the second converter station from being grounded through the grounding electrode line on its side to being grounded through the grounding electrode line on the first converter station.

[0067] For example, in step S150, see Figure 2 , the second current value is 1500 amperes, the protection value of the first conversion switch 14 is 20 amperes, and the computer system determines that the second current value is greater than or equal to the protection value of the first conversion switch. The computer system sends a fourth instruction to the second converter station 12, so that the second converter station 12 disconnects the second conversion switch 15, thereby completing the conversion process of the second converter station 12 from being connected to the grounding device through the second conversion switch 15-second grounding electrode line 17 to being connected to the grounding device through the first conversion switch 14-second DC line 13-first converter station 11-first grounding electrode line 16.

[0068] Through the above-mentioned embodiments, the present application, when determining that the first current value of the first conversion switch meets the first preset condition, increases the current value flowing through the first conversion switch by closing the grounding switch of the third converter station, so that the computer system can effectively identify the effective establishment of the transfer branch.

[0069] The technical solution of the present application can avoid the problem that the computer system cannot identify whether the transfer branch is effectively established because the current value flowing through the first conversion switch is less than the protection setting value set by the first conversion switch, thereby causing the grounding line conversion to be interrupted.

[0070] Optionally, in the topology of the split-address cascade DC power transmission system, the receiving end may also be a split-address cascade DC layout.

[0071] Optionally, in the topological structure of the split-site cascaded DC transmission system, the sending end is a conventional UHV DC layout, and the receiving end is a split-site cascaded DC layout.

[0072] Optionally, the present application also provides a grounding conversion method 2000 for a split-address cascaded DC power transmission system, see Figure 4 The grounding conversion method 2000 includes steps S210 to S260. Exemplarily, the grounding conversion method 2000 may be executed by a computer system, and the computer system may be a client device (such as a host, etc.) with data processing capabilities.

[0073] See also Figure 4 Steps S210 to S250 in the grounding conversion method 2000 are the same as steps S110 to S150 in the grounding conversion method 1000, and are not described in detail herein.

[0074] In step S260, a fifth instruction is sent to the third converter station, so that the third converter station opens the grounding switch in response to the fifth instruction.

[0075] According to an example embodiment, the fifth instruction may be generated after the computer system completes the conversion of the grounding electrode line of the second converter station, and the fifth instruction may include instruction information for disconnecting the grounding switch of the third converter station.

[0076] For example, in step S260, the computer system sends a fifth instruction to the third converter station 21, so that the third converter station 21 disconnects the grounding switch in response to the fifth instruction, thereby preventing a large current from flowing through the grounding device connected to the third converter station 21 for a long time.

[0077] Optionally, the first instruction may include a conversion threshold of the second converter station. For example, the conversion threshold may include information such as conversion time and conversion parameters.

[0078] See also Figure 5 , step S230 in the grounding conversion method 2000 includes step S231 and step S232.

[0079] In step S231, it is determined that the first current value satisfies a first preset condition, and a second instruction is determined according to a switching threshold of the second converter station.

[0080] According to an example embodiment, the second instruction may also be instruction information generated according to the switching threshold information of the second converter station to close the grounding switch of the third converter station. Figure 2 The computer system determines that the first current value is less than the protection value of the first conversion switch, and the computer system determines the second instruction according to the conversion time and conversion parameters in the conversion threshold of the second converter station 12.

[0081] In step S232, a second instruction is sent to the third converter station, so that the third converter station closes the grounding switch of the third converter station in response to the second instruction.

[0082] According to an example embodiment, the computer system generates the second instruction according to the switching threshold value, which may cause the third converter station to more definitely close the grounding switch of the third converter station.

[0083] For example, in step S232, see Figure 2 , the computer system sends a second instruction to the third converter station 21, so that the third converter station 21 closes the grounding switch 22 of the third converter station 21 in response to the second instruction.

[0084] Optionally, the grounding switch of the third converter station includes a first grounding switch and a second grounding switch. Figure 6 , step S230 in the grounding conversion method 2000 also includes step S233.

[0085] In step S233, if it is determined that the first current value satisfies the first preset condition, a second instruction is sent to the third converter station, so that the third converter station closes the first grounding switch or the second grounding switch in response to the second instruction.

[0086] According to an example embodiment, see Figure 2 The grounding switch 22 of the third converter station 21 includes a first grounding switch 23 and a second grounding switch 24, and the first grounding switch 23 and the second grounding switch 24 are connected in parallel.

[0087] For example, in step S233, see Figure 2 , the computer system determines that the first current value is less than the protection value of the first conversion switch. Then the computer system sends a second instruction to the third converter station 21, so that the third converter station 21 closes the first grounding switch 23 of the third converter station 21 in response to the second instruction. The DC current flows into the grounding device of the second converter station 12 through the grounding device of the first grounding switch 23.

[0088] For another example, the computer system sends a second instruction to the third converter station 21, so that the third converter station 21 closes the second grounding switch 24 of the third converter station 21 in response to the second instruction. The DC current flows into the grounding device of the second converter station 12 through the grounding device of the second grounding switch 24. Providing two grounding switches can improve the stability of the grounding conversion method 2000.

[0089] Optionally, the grounding device of the first grounding switch is arranged in the area of ​​the third converter station, see Figure 7 , step S230 in the grounding conversion method 2000 further includes steps S231a and S232a, wherein step S231 includes step S231a, and step S232 includes step S232a.

[0090] In step S231a, it is determined that the first current value satisfies the first preset condition, and it is determined that the conversion threshold satisfies the first conversion threshold condition, and then the second instruction is determined according to the conversion threshold.

[0091] According to an example embodiment, the first conversion threshold condition may be that the conversion time in the conversion threshold is less than or equal to 3 seconds.

[0092] See also Figure 2 The grounding device of the first grounding switch 23 is arranged in the area of ​​the third converter station 21. The closing time of the first grounding switch 23 is relatively fast, generally in the millisecond level, so that the first grounding switch 23 can be closed quickly.

[0093] For example, in step S231a, see Figure 2, the computer system determines that the first current value is less than the protection value of the first conversion switch 14, and determines that the conversion time in the conversion threshold is 3 seconds, then the computer system determines the second instruction according to the conversion time and conversion parameters in the conversion threshold of the second converter station 12. The second instruction may also include instruction information for closing the first grounding switch 23 of the third converter station 21 within 3 seconds.

[0094] In step S232a, a second instruction is sent to the third converter station, so that the third converter station closes the first grounding switch in response to the second instruction.

[0095] According to the exemplary embodiment, the computer system determines a second instruction to quickly close the first grounding switch, and then sends the second instruction to the third converter station. For example, in step S232a, see Figure 2 , the computer system sends a second instruction to the third converter station 21 to close the first grounding switch 23 within 3 seconds, so that the third converter station 21 closes the first grounding switch 23 within 3 seconds in response to the second instruction. Thus, the computer system can quickly complete the conversion process between the second converter station 12 being grounded through the grounding electrode line on the local side and being grounded through the grounding electrode line of the first converter station 11.

[0096] Optionally, the grounding device of the second grounding switch is arranged outside the area of ​​the third converter station. Figure 8 , step S230 in the grounding conversion method 2000 further includes steps S231b and S232b, wherein step S231 further includes step S231b, and step S232 further includes step S232b.

[0097] In step S231b, it is determined that the first current value satisfies the first preset condition, and it is determined that the conversion threshold satisfies the second conversion threshold condition, and then a second instruction is determined according to the conversion threshold.

[0098] According to an example embodiment, the second conversion threshold condition may be that the conversion time in the conversion threshold is greater than 3 seconds.

[0099] See also Figure 2 , the grounding device of the second grounding switch 24 is arranged outside the area of ​​the third converter station 21. Two knife switches (not shown in the figure) are usually arranged on both sides of the second grounding switch 24. In the process of closing the second grounding switch 24, the two knife switches on both sides of the second grounding switch 24 need to be closed first, and then the second grounding switch 24 is closed, resulting in a relatively slow closing time of the second grounding switch 24, which can generally be in the order of ten seconds.

[0100] For example, in step S231b, see Figure 2, the computer system determines that the first current value is less than the protection value of the first transfer switch, and determines that the transfer time in the transfer threshold is 60 seconds, then the computer system determines the second instruction according to the transfer time and transfer parameters in the transfer threshold of the second converter station 12. The second instruction may also include instruction information for closing the second grounding switch 24 of the third converter station 21 within 60 seconds.

[0101] In step S232b, a second instruction is sent to the third converter station, so that the third converter station closes the second grounding switch in response to the second instruction.

[0102] According to the exemplary embodiment, the computer system determines a second instruction to close the second grounding switch, and then sends the second instruction to the third converter station. For example, in step S232b, see Figure 2 , the computer system sends a second instruction to the third converter station 21 to close the second grounding switch 24 within 60 seconds, so that the third converter station 21 closes the second grounding switch 24 within 60 seconds in response to the second instruction. Thus, the computer system can complete the conversion process of the second converter station 12 from grounding through the grounding electrode line on the local side to grounding through the grounding electrode line of the first converter station 11 in a longer time.

[0103] Alternatively, see Fig. 9 , step S260 in the grounding conversion method 2000 also includes step S261.

[0104] In step S261, a fifth instruction is sent to the third converter station, so that the third converter station disconnects the first grounding switch or the second grounding switch in response to the fifth instruction.

[0105] According to an example embodiment, the grounding device of the first grounding switch is arranged in the area of ​​the third converter station, and according to the overcurrent protection requirements of the station grounding switch, the closing time of the first grounding switch is less than or equal to 3 seconds. This is to avoid the situation where a large current flows through the grounding device in the area of ​​the third converter station for a long time. The computer system can set the first closing time of the first grounding switch to 1 second.

[0106] The grounding device of the second grounding switch is arranged outside the area of ​​the third converter station. According to the dispatching requirements of the DC transmission system, the closing time of the second grounding switch can be maintained for a certain time, for example, the time can be in the order of hours. However, it should not exceed several hours to avoid the situation where a large current flows through the grounding device outside the area of ​​the third converter station for a long time. The computer system can set the second closing time of the second grounding switch to 2 minutes.

[0107] For example, in step S261, see Figure 2, the computer system sends a fifth instruction to the third converter station 21, so that the third converter station 21 responds to the fifth instruction and opens the first grounding switch 23 within the first closing time. Alternatively, in step S261, the computer system sends a fifth instruction to the third converter station 21, so that the third converter station 21 responds to the fifth instruction and opens the second grounding switch 24 within the second closing time.

[0108] Optionally, the present application also provides a grounding conversion method 3000 for a split-address cascaded DC power transmission system, see Fig.10 The grounding conversion method 3000 includes steps S310 to S380. Exemplarily, the grounding conversion method 3000 may be executed by a computer system, and the computer system may be a client device (such as a host, etc.) with data processing capabilities.

[0109] According to an example embodiment, the grounding switch of the third converter station includes a first grounding switch and a second grounding switch, the grounding device of the first grounding switch is arranged in the area of ​​the third converter station, and the grounding device of the second grounding switch is arranged outside the area of ​​the third converter station.

[0110] The closing time of the first grounding switch and the second grounding switch will not be described in detail here.

[0111] In step S310, a third current value of the converter of the second converter station is collected.

[0112] According to an exemplary embodiment, the computer system may collect the third current value of the converter passing through the second converter station periodically or in real time by means of an electronic current transformer or an optical current transformer.

[0113] For example, in step S310, see Figure 2 The computer system can collect the third current value of 5000 amperes passing through the high-voltage converter 19 of the second converter station 12 in real time through an electronic current transformer.

[0114] In step S320, a first current value of a first switch of the second converter station is determined according to the third current value.

[0115] According to an example embodiment, the third current value may be a current value of a main circuit in a parallel circuit, and the first current value may be a current value of a branch circuit in a parallel circuit. The computer system may determine the first current value according to the third current value based on the relationship between the main circuit current and the branch current in the parallel circuit.

[0116] For example, see Figure 2The computer system can calculate the first current value flowing through the first conversion switch 14 and the fourth current value of the second conversion switch 15 according to the third current value, the resistance value of the first grounding electrode line 16, the resistance value of the second grounding electrode line 17, the resistance value of the second DC line 13, and the resistance value between the second conversion switch 15 and the high-voltage converter 19. The calculation formula can be:

[0117]

[0118] I4=I3-I1;

[0119] Among them, I3 is the third current value, R 16 is the resistance value of the first grounding electrode line 16, R 17 is the resistance value of the second grounding electrode line 17, R 13 is the resistance value of the second DC line 13, R 15 is the resistance value between the second conversion switch 15 and the high-voltage converter 19, I1 is the first current value, and I4 is the fourth current value.

[0120] For example, in step S320, see Figure 2 , the third current value is 5000 amperes. The computer system determines the first current value to be 10 amperes according to the third current value.

[0121] In step S330, a first instruction from a first converter station is received.

[0122] According to an example embodiment, the first instruction may also be instruction information that the valve group of the first converter station will start operating within the first time.

[0123] The first time can be in seconds, minutes, or hours.

[0124] For example, in step S330, see Figure 2 The computer system receives a first instruction from the first converter station 11. The grounding mode of the second converter station 12 needs to be converted from grounding through the grounding electrode line on the local side to grounding through the grounding electrode line of the first converter station 11 within the first time.

[0125] In step S340, if it is determined according to the first instruction that the first current value satisfies the first preset condition, a second instruction is sent to the third converter station, so that the third converter station closes the second grounding switch in response to the second instruction.

[0126] According to the example embodiment, since the first time may be in the order of seconds, minutes, or hours, the second grounding switch of the third converter station may be closed in advance to wait for the switching of the grounding mode of the second converter station.

[0127] For example, in step S340, see Figure 2 After receiving the first instruction, the computer system determines that the first current value is less than the protection value of the first conversion switch. Then the computer system sends a second instruction to the third converter station 21, so that the third converter station 21 closes the second grounding switch 24 in response to the second instruction. The first DC line 32 of the second pole is short-circuited. The DC current flows into the grounding device of the second converter station 12 through the grounding device of the third converter station 21.

[0128] In step S350, in response to the third instruction from the third converter station, a sixth instruction is sent to the second converter station, so that the second converter station closes the first transfer switch in response to the sixth instruction.

[0129] According to an example embodiment, the third instruction may be feedback instruction information generated after the third converter station closes the grounding switch.

[0130] The sixth instruction may be generated by the computer system after receiving the third instruction, and the sixth instruction may include instruction information for closing the first switch of the second converter station. Thus, the computer system establishes a grounding transfer branch of the second converter station, that is, a branch in which the second converter station is grounded through the grounding electrode line of the first converter station.

[0131] For example, in step S350, see Figure 2 After receiving the third instruction, the computer system generates a sixth instruction in response to the third instruction, and sends the sixth instruction to the second converter station 12, so that the second converter station 12 closes the first transfer switch 14 in response to the sixth instruction.

[0132] In step S360, a second current value of the first conversion switch is collected.

[0133] According to an exemplary embodiment, after the first conversion switch is closed, the computer system may collect the current value flowing through the first conversion switch by means of an electronic current transformer or an optical current transformer. Figure 2 The computer system can collect the second current value of the first conversion switch 14 through an electronic current transformer.

[0134] See also Fig.10 Step S370 in the grounding conversion method 3000 is the same as step S150 in the grounding conversion method 1000, and will not be described in detail herein.

[0135] Through the above-mentioned embodiments, the present application collects the second current value of the converter of the second converter station, and determines the first current value of the first conversion switch according to the second current value. The present application closes the second grounding switch of the third converter station before converting the DC current grounding mode of the second converter station, thereby waiting for the grounding conversion process of the second converter station, thereby reducing the time during the conversion process, and quickly completing the conversion process of the second converter station from grounding through the grounding electrode line on this side to grounding through the grounding electrode line of the first converter station.

[0136] Alternatively, see Fig.11 , the ground conversion method 3000 may further include step S380.

[0137] In step S380, a fifth instruction is sent to the third converter station, so that the third converter station opens the second grounding switch in response to the fifth instruction.

[0138] According to an example embodiment, the fifth instruction may be generated after the computer system completes conversion of the grounding electrode line of the second converter station, and the fifth instruction may include instruction information for disconnecting the second grounding switch of the third converter station.

[0139] The grounding device of the second grounding switch is set outside the area of ​​the third converter station. The DC transmission system scheduling requires that the closing time of the second grounding switch can be maintained for a certain time, for example, the time can be in the order of hours. However, it should not exceed several hours to avoid the situation where a large current flows through the grounding device outside the area of ​​the third converter station for a long time. The computer system can set the second closing time of the second grounding switch to 2 minutes.

[0140] For example, in step S380, see Figure 2 , the computer system sends a fifth instruction to the third converter station 21, so that the third converter station 21 responds to the fifth instruction and opens the second grounding switch 24 within the second closing time.

[0141] According to one aspect of the present application, a grounding conversion system 4000 of a split-address cascaded DC power transmission system is also provided. Fig.12 The ground conversion system 4000 includes a processing module 4100 and a collection module 4200 .

[0142] According to an example embodiment, the processing module 4100 receives a first instruction from a first converter station.

[0143] According to an example embodiment, the first instruction may be instruction information for putting the first converter station into operation. The first instruction may be generated and sent by the first converter station.

[0144] For example, the processing module 4100 receives a first instruction from the first converter station. The grounding mode of the second converter station needs to be converted from grounding through the grounding electrode line on the local side to grounding through the grounding electrode line of the first converter station. For example, see Figure 2 The grounding method of the second converter station 12 needs to be converted from being connected to the grounding device through the second conversion switch 15-the second grounding electrode line 17 to being connected to the grounding device through the first conversion switch 14-the second DC line 13-the first converter station 11-the first grounding electrode line 16.

[0145] According to an example embodiment, after receiving the first instruction, the processing module 4100 closes the first transfer switch of the second converter station in response to the first instruction. After the first transfer switch is closed, the processing module 4100 establishes a grounding transfer branch of the second converter station, that is, establishes a branch in which the second converter station is grounded through the grounding electrode line of the first converter station.

[0146] According to an example embodiment, the acquisition module 4200 receives the first instruction transmitted by the processing module 4100, and acquires the first current value of the first transfer switch of the second converter station according to the first instruction.

[0147] According to the first instruction, the acquisition module 4200 can acquire the first current value flowing through the first conversion switch by means of an electronic current transformer or an optical current transformer. Figure 2 The acquisition module 4200 can acquire the first current value of the first conversion switch 14 by means of an electronic current transformer, which is 10 amperes.

[0148] According to an example embodiment, the processing module 4100 also receives and determines a first current value, and if it is determined that the first current value satisfies a first preset condition, sends a second instruction to the third converter station so that the third converter station closes the grounding switch of the third converter station in response to the second instruction.

[0149] According to an example embodiment, the first preset condition may be that the first current value of the first conversion switch is less than a protection value of the first conversion switch. The protection value of the first conversion switch may be determined according to a zero drift value of a current measurement point next to the first conversion switch.

[0150] According to an example embodiment, the second instruction may be instruction information for closing the grounding switch of the third converter station. The third converter station closes the grounding switch of the third converter station in response to the second instruction, and after the DC current flows into the grounding device of the second converter station through the grounding device of the third converter station, the DC current flows into the high-voltage converter of the second converter station through the grounding electrode line of the second converter station and the second conversion switch; the DC current also flows into the high-voltage converter of the second converter station through the grounding electrode line of the first converter station, the first converter station, the DC line between the first converter station and the second converter station, and the first conversion switch.

[0151] For example, see Figure 2 , the first current value is 10 amperes, the protection value of the first conversion switch 14 is 20 amperes, and the processing module 4100 determines that the first current value is less than the protection value of the first conversion switch. Then the processing module 4100 sends a second instruction to the third converter station, so that the third converter station closes the grounding switch of the third converter station in response to the second instruction.

[0152] See also Figure 2 The third converter station 21 closes the grounding switch 22 of the third converter station 21 in response to the second instruction. The DC current flows into the grounding device of the second converter station 12 through the grounding device of the third converter station 21, and then flows into the high-voltage converter 19 of the second converter station 12 through the third branch: the second grounding electrode line 17-the second conversion switch 15; the DC current also flows into the high-voltage converter 19 of the second converter station 12 through the fourth branch: the first grounding electrode line 16-the first converter station 11-the second DC line 13-the first conversion switch 14.

[0153] See also Figure 2 , the third branch is connected in parallel with the fourth branch. The fourth branch is increased in resistance value relative to the second branch by adding a second grounding electrode line 17 relative to the second branch. The third branch is reduced in resistance value relative to the first branch by reducing a second grounding electrode line 17 relative to the first branch. Thus, the current value flowing through the first conversion switch 14 is increased.

[0154] According to an exemplary embodiment, the processing module 4100 receives a third instruction from a third converter station. The collecting module 4200 receives the third instruction transmitted by the processing module 4100, and collects the second current value of the first transfer switch according to the third instruction.

[0155] For example, see Figure 2 After the acquisition module 4200 receives the third instruction, according to the third instruction, the acquisition module 4200 can acquire the second current value of the first conversion switch 14 as 1500 amperes through an electronic current transformer or an optical current transformer.

[0156] According to the example embodiment, the processing module 4100 further determines that the second current value satisfies the second preset condition, and then sends a fourth instruction to the second converter station, so that the second converter station disconnects the second transfer switch of the second converter station in response to the fourth instruction.

[0157] According to an example embodiment, the second preset condition may be that the second current value of the first conversion switch is greater than or equal to a protection value of the first conversion switch.

[0158] The fourth instruction may be instruction information for disconnecting the second conversion switch generated when the processing module 4100 determines that the second current value satisfies the second preset condition. After the second conversion switch is disconnected, the processing module 4100 disconnects the branch connected to the second converter station through the grounding electrode line on its side, thereby completing the conversion process of the second converter station from being grounded through the grounding electrode line on its side to being grounded through the grounding electrode line of the first converter station.

[0159] For example, see Figure 2 , the second current value is 1500 amperes, the protection value of the first conversion switch 14 is 20 amperes, and the processing module 4100 determines that the second current value is greater than or equal to the protection value of the first conversion switch. The processing module 4100 sends a fourth instruction to the second converter station 12, so that the second converter station 12 disconnects the second conversion switch 15, thereby completing the conversion process of the second converter station 12 from being connected to the grounding device through the second conversion switch 15-the second grounding electrode line 17 to being connected to the grounding device through the first conversion switch 14-the second DC line 13-the first converter station 11-the first grounding electrode line 16.

[0160] Through the above-mentioned embodiments, the present application, when determining that the first current value of the first conversion switch meets the first preset condition, increases the current value flowing through the first conversion switch by closing the grounding switch of the third converter station, so that the computer system can effectively identify the effective establishment of the transfer branch.

[0161] The technical solution of the present application can avoid the problem that the computer system cannot identify whether the transfer branch is effectively established because the current value flowing through the first conversion switch is less than the protection setting value set by the first conversion switch, thereby causing the grounding line conversion to be interrupted.

[0162] Optionally, the processing module 4100 further sends a fifth instruction to the third converter station, so that the third converter station disconnects the grounding switch in response to the fifth instruction.

[0163] According to an example embodiment, the fifth instruction may be generated after the processing module 4100 completes the conversion of the grounding electrode line of the second converter station, and the fifth instruction may include instruction information for disconnecting the grounding switch of the third converter station.

[0164] For example, see Figure 2 The processing module 4100 sends a fifth instruction to the third converter station 21, so that the third converter station 21 disconnects the grounding switch in response to the fifth instruction, thereby preventing the grounding device connected to the third converter station 21 from flowing through a large current for a long time.

[0165] Optionally, the first instruction includes a conversion threshold of the first converter station. For example, the conversion threshold may include information such as conversion time and conversion parameters.

[0166] According to an example embodiment, the processing module 4100 further determines that the first current value satisfies a first preset condition, and determines a second instruction according to a switching threshold of the first converter station.

[0167] According to an example embodiment, the second instruction may also be instruction information generated according to the switching threshold information of the second converter station to close the grounding switch of the third converter station. Figure 2 The processing module 4100 determines that the first current value is less than the protection value of the first conversion switch 14 , and the processing module 4100 determines the second instruction according to the conversion time and conversion parameters in the conversion threshold of the second converter station 12 .

[0168] According to an example embodiment, the processing module 4100 further sends a second instruction to the third converter station, so that the third converter station closes the grounding switch of the third converter station in response to the second instruction.

[0169] According to an example embodiment, the processing module 4100 generates a second instruction according to the switching threshold, so that the third converter station can more clearly close the grounding switch of the third converter station.

[0170] For example, see Figure 2 , the processing module 4100 sends a second instruction to the third converter station 21, so that the third converter station 21 closes the grounding switch 22 of the third converter station 21 in response to the second instruction.

[0171] Optionally, the grounding switch of the third converter station includes a first grounding switch and a second grounding switch. Figure 2 , the first grounding switch 23 and the second grounding switch 24 are connected in parallel.

[0172] According to an example embodiment, the processing module 4100 further determines that the first current value satisfies the first preset condition, and then sends a second instruction to the third converter station, so that the third converter station closes the first grounding switch or the second grounding switch in response to the second instruction.

[0173] For example, see Figure 2 , the processing module 4100 determines that the first current value is less than the protection value of the first conversion switch. Then the computer system sends a second instruction to the third converter station 21, so that the third converter station 21 closes the first grounding switch 23 of the third converter station 21 in response to the second instruction, and the DC current flows into the grounding device of the second converter station 12 through the grounding device of the first grounding switch 23.

[0174] For another example, the processing module 4100 sends a second instruction to the third converter station 21, so that the third converter station 21 closes the second grounding switch 24 of the third converter station 21 in response to the second instruction, and the DC current flows into the grounding device of the second converter station 12 through the grounding device of the second grounding switch 24. Providing two grounding switches can improve the stability of the grounding conversion system 4000.

[0175] Optionally, the grounding device of the first grounding switch is arranged in the area of ​​the third converter station. Figure 2 The grounding device of the first grounding switch 23 is arranged in the area of ​​the third converter station 21. The closing time of the first grounding switch 23 is relatively fast, generally in the millisecond level, so that the first grounding switch can be closed quickly.

[0176] According to an example embodiment, the processing module 4100 further determines that the first current value satisfies a first preset condition and determines that the conversion threshold satisfies a second conversion threshold condition, and then determines a second instruction according to the conversion threshold.

[0177] According to an example embodiment, the first conversion threshold condition may be that the conversion time in the conversion threshold is less than or equal to 3 seconds.

[0178] For example, see Figure 2 , the processing module 4100 determines that the first current value is less than the protection value of the first conversion switch 14, and determines that the conversion time in the conversion threshold is 3 seconds, then the processing module 4100 determines the second instruction according to the conversion time and conversion parameters in the conversion threshold of the second converter station 12. The second instruction may also include instruction information for closing the first grounding switch of the third converter station 21 within 3 seconds.

[0179] According to an example embodiment, the processing module 4100 further sends a second instruction to the third converter station, so that the third converter station closes the second grounding switch in response to the second instruction.

[0180] According to an exemplary embodiment, the processing module 4100 determines a second instruction to quickly close the first grounding switch, and then sends the second instruction to the third converter station. Figure 2 , the processing module 4100 sends a second instruction to the third converter station 21 to close the first grounding switch 23 within 3 seconds, so that the third converter station 21 closes the first grounding switch 23 within 3 seconds in response to the second instruction. Thus, the grounding conversion system 4000 can quickly complete the conversion process between the second converter station 12 being grounded through the grounding electrode line on the local side and being grounded through the grounding electrode line of the first converter station 11.

[0181] Optionally, the grounding device of the second grounding switch is arranged outside the area of ​​the third converter station. Figure 2, the grounding device of the second grounding switch 24 is arranged outside the area of ​​the third converter station 21. Two knife switches (not shown in the figure) are usually arranged on both sides of the second grounding switch 24. In the process of closing the second grounding switch 24, it is necessary to close the two knife switches on both sides of the second grounding switch 24 first, and then close the second grounding switch 24, resulting in a relatively slow closing time of the second grounding switch 24, which can generally be in the order of ten seconds).

[0182] According to an example embodiment, the processing module 4100 determines that the first current value satisfies the first preset condition and determines that the conversion threshold satisfies the second conversion threshold condition, and then determines the second instruction according to the conversion threshold.

[0183] According to an example embodiment, the second conversion threshold condition may be that the conversion time in the conversion threshold is greater than 3 seconds.

[0184] For example, see Figure 2 , the processing module 4100 determines that the first current value is less than the protection value of the first conversion switch 14, and determines that the conversion time in the conversion threshold is 4 seconds, then the processing module 4100 determines the second instruction according to the conversion time and conversion parameters in the conversion threshold of the second converter station 12. The second instruction may also include instruction information for closing the second grounding switch of the third converter station 21 within 60 seconds.

[0185] According to an example embodiment, the processing module 4100 sends a second instruction to the third converter station, so that the third converter station closes the second grounding switch in response to the second instruction.

[0186] According to an exemplary embodiment, the processing module 4100 determines a second instruction to close the second grounding switch, and then sends the second instruction to the third converter station. Figure 2 , the processing module 4100 sends a second instruction to the third converter station 21 to close the second grounding switch 24 within 60 seconds, so that the third converter station 21 responds to the second instruction and closes the second grounding switch 24 within 60 seconds. Thus, the grounding conversion system 4000 can complete the conversion process of the second converter station 12 from grounding through the grounding electrode line on the local side to grounding through the grounding electrode line of the first converter station 11 in a longer time.

[0187] Optionally, the grounding switch of the third converter station includes a first grounding switch and a second grounding switch, the grounding device of the first grounding switch is arranged in the area of ​​the third converter station, and the grounding device of the second grounding switch is arranged outside the area of ​​the third converter station.

[0188] According to an example embodiment, the collection module 4200 further collects a third current value of the converter of the second converter station.

[0189] According to an exemplary embodiment, the acquisition module 4200 may acquire the third current value of the converter passing through the second converter station periodically or in real time by means of an electronic current transformer or an optical current transformer.

[0190] For example, see Figure 2 The acquisition module 4200 can collect the third current value of 5000 amperes passing through the high-voltage converter 19 of the second converter station 12 in real time by means of an electronic current transformer.

[0191] According to an example embodiment, the processing module 4100 further determines the first current value based on the third current value, and if it is determined that the first current value satisfies the first preset condition, the processing module 4100 sends a second instruction to the third converter station so that the third converter station closes the second grounding switch in response to the second instruction.

[0192] According to an example embodiment, the third current value may be a current value of a main circuit in a parallel circuit, and the first current value may be a current value of a branch circuit in a parallel circuit. The processing module 4100 may determine the first current value according to the third current value based on the relationship between the main circuit current and the branch current in the parallel circuit.

[0193] For example, see Figure 2 The processing module 4100 can calculate the first current value flowing through the first conversion switch 14 and the fourth current value of the second conversion switch 15 according to the third current value, the resistance value of the first grounding electrode line 16, the resistance value of the second grounding electrode line 17, the resistance value of the second DC line 13, and the resistance value between the second conversion switch 15 and the high-voltage converter 19. The calculation formula can be:

[0194]

[0195] I4=I3-I1;

[0196] Among them, I3 is the third current value, R 16 is the resistance value of the first grounding electrode line 16, R 17 is the resistance value of the second grounding electrode line 17, R 13 is the resistance value of the second DC line 13, R 15 is the resistance value between the second conversion switch 15 and the high-voltage converter 19, I1 is the first current value, and I4 is the fourth current value.

[0197] For example, see Figure 2 , the third current value is 5000 amperes. The processing module 4100 determines that the first current value is 10 amperes according to the third current value.

[0198] According to an example embodiment, the processing module 4100 receives a first instruction from the first converter station. The first instruction may also be instruction information that the valve group of the first converter station is about to start operating within a first time.

[0199] The first time can be in seconds, minutes, or hours.

[0200] For example, see Figure 2 The processing module 4100 receives a first instruction from the first converter station 11. The grounding mode of the second converter station 12 needs to be converted from grounding through the grounding electrode line on the local side to grounding through the grounding electrode line of the first converter station 11 within the first time.

[0201] According to an example embodiment, the processing module 4100 determines that the first current value satisfies the first preset condition, and then sends a second instruction to the third converter station, so that the third converter station closes the second grounding switch in response to the second instruction.

[0202] According to the exemplary embodiment, since the first time can be in the order of seconds, minutes, or hours, the second grounding switch of the third converter station can be closed in advance to wait for the conversion of the grounding mode of the second converter station. Figure 2 , the processing module 4100 determines that the first current value is less than the protection value of the first conversion switch 14. Then the processing module 4100 sends a second instruction to the third converter station 21, so that the third converter station 21 closes the second grounding switch 24 in response to the second instruction. The first DC line 32 of the second pole is short-circuited. The DC current flows into the grounding device of the second converter station 12 through the grounding device of the second grounding switch 24.

[0203] According to an example embodiment, the processing module 4100 sends a sixth instruction to the second converter station in response to a third instruction from the third converter station, so that the second converter station closes the first transfer switch in response to the sixth instruction;

[0204] According to an example embodiment, the third instruction may be feedback instruction information generated after the third converter station closes the grounding switch. The sixth instruction may be generated after the processing module 4100 receives the third instruction, and the sixth instruction may include instruction information for closing the first transfer switch of the second converter station. Thus, the processing module 4100 establishes a grounding transfer branch of the second converter station, that is, establishes a branch in which the second converter station is grounded through the grounding electrode line of the first converter station.

[0205] For example, see Figure 2 After receiving the third instruction, the processing module 4100 generates a sixth instruction in response to the third instruction, and sends the sixth instruction to the second converter station 12 so that the second converter station 12 closes the first conversion switch 14 in response to the sixth instruction.

[0206] According to an example embodiment, the acquisition module 4200 further acquires a second current value of the first conversion switch.

[0207] According to an exemplary embodiment, after the first transfer switch is closed, for example, see Figure 2 The acquisition module 4200 can acquire the second current value of the first conversion switch 14 by means of an electronic current transformer or an optical current transformer.

[0208] Through the above-mentioned embodiments, the present application collects the second current value of the converter of the second converter station, and determines the first current value of the first conversion switch according to the second current value. The present application closes the second grounding switch of the third converter station before converting the DC current grounding mode of the second converter station, thereby waiting for the grounding conversion process of the second converter station, thereby reducing the time during the conversion process, and quickly completing the conversion process of the second converter station from grounding through the grounding electrode line on this side to grounding through the grounding electrode line of the first converter station.

[0209] Optionally, the processing module 4100 further sends a fifth instruction to the third converter station, so that the third converter station disconnects the first grounding switch or the second grounding switch in response to the fifth instruction.

[0210] According to the exemplary embodiment, the grounding device of the first grounding switch is arranged in the area of ​​the third converter station, and according to the overcurrent protection requirement of the station grounding switch, the closing time of the first grounding switch is less than or equal to 3 seconds. In order to avoid the situation where a large current flows through the grounding device in the area of ​​the third converter station for a long time, the processing module 4100 can set the first closing time of the first grounding switch to 1 second.

[0211] The grounding device of the second grounding switch is arranged outside the area of ​​the third converter station. According to the dispatching requirements of the DC transmission system, the closing time of the second grounding switch can be maintained for a certain time, for example, the time can be in the order of hours. However, it should not exceed several hours to avoid the situation where a large current flows through the grounding device outside the area of ​​the third converter station for a long time. The processing module 4100 can set the second closing time of the second grounding switch to 2 minutes.

[0212] For example, see Figure 2 , the processing module 4100 sends a fifth instruction to the third converter station 21, so that the third converter station 21 responds to the fifth instruction and opens the first grounding switch 23 within the first closing time. Alternatively, the processing module 4100 sends a fifth instruction to the third converter station 21, so that the third converter station 21 responds to the fifth instruction and opens the second grounding switch 24 within the second closing time.

[0213] According to one aspect of the present application, a non-volatile computer-readable storage medium is further provided, on which a computer program is stored. When the computer program is executed by a processor, the grounding conversion method of the split-address cascaded DC transmission system as described above can be implemented.

[0214] According to one aspect of the present application, there is also provided an electronic device, comprising: one or more processors; a storage device for storing one or more programs, wherein when the one or more programs are executed by the one or more processors, the one or more processors are enabled to implement the grounding conversion method of the distributed cascaded DC transmission system as described above.

[0215] According to one aspect of the present application, a computer program product is also provided, comprising: a computer program stored on a computer-readable storage medium; the computer program comprises program instructions, and when the program instructions are executed by a computer, the computer executes the grounding conversion method of the split-address cascaded DC transmission system as described above.

[0216] According to one aspect of the present application, a non-volatile computer-readable storage medium is further provided, on which a computer program is stored. When the computer program is executed by a processor, the grounding conversion method of the split-address cascaded DC transmission system as described above can be implemented.

[0217] According to one aspect of the present application, there is also provided an electronic device, comprising: one or more processors; a storage device for storing one or more programs, wherein when the one or more programs are executed by the one or more processors, the one or more processors are enabled to implement the grounding conversion method of the distributed cascaded DC transmission system as described above.

[0218] According to one aspect of the present application, a computer program product is also provided, comprising: a computer program stored on a computer-readable storage medium; the computer program comprises program instructions, and when the program instructions are executed by a computer, the computer executes the grounding conversion method of the split-address cascaded DC transmission system as described above.

[0219] Finally, it should be noted that the above are only preferred embodiments of the present application and are not intended to limit the present application. Although the present application is described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions of the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A grounding conversion method for a cascaded DC power transmission system, characterized in that: The grounding conversion method comprises: receiving a first instruction from a first converter station; Determining a first current value of a first switch of a second converter station according to the first instruction; If it is determined that the first current value satisfies a first preset condition, a second instruction is sent to the third converter station, so that the third converter station closes the grounding switch of the third converter station in response to the second instruction; In response to a third instruction from a third converter station, collecting a second current value of the first transfer switch; If it is determined that the second current value satisfies the second preset condition, a fourth instruction is sent to the second converter station, so that the second converter station disconnects the second transfer switch of the second converter station in response to the fourth instruction.

2. The grounding transfer switch according to claim 1, characterized in that: After determining that the second current value satisfies the second preset condition and sending a fourth instruction to the second converter station, the grounding transfer switch method further includes: A fifth instruction is sent to the third converter station, so that the third converter station opens the grounding switch in response to the fifth instruction.

3. The grounding transfer switch according to claim 2, characterized in that: The first instruction includes a switching threshold of the second converter station; The step of determining that the first current value satisfies the first preset condition and then sending a second instruction to the third converter station so that the third converter station closes the grounding switch of the third converter station in response to the second instruction comprises: Determining that the first current value satisfies the first preset condition, and determining the second instruction according to the conversion threshold of the second converter station; The second instruction is sent to the third converter station, so that the third converter station closes the grounding switch of the third converter station in response to the second instruction.

4. The grounding conversion method according to claim 3, characterized in that: The grounding switch of the third converter station includes a first grounding switch and a second grounding switch; The step of determining that the first current value satisfies the first preset condition and then sending a second instruction to the third converter station so that the third converter station closes the grounding switch of the third converter station in response to the second instruction comprises: If it is determined that the first current value satisfies the first preset condition, a second instruction is sent to the third converter station, so that the third converter station closes the first grounding switch or the second grounding switch in response to the second instruction.

5. The grounding conversion method according to claim 4, characterized in that: The grounding device of the first grounding switch is arranged in the area of ​​the third converter station; The determining that the first current value satisfies the first preset condition and determining the second instruction according to the conversion threshold of the second converter station includes: Determining that the first current value satisfies the first preset condition, and determining that the conversion threshold satisfies a first conversion threshold condition, and then determining the second instruction according to the conversion threshold; The sending the second instruction to the third converter station so that the third converter station closes the grounding switch of the third converter station in response to the second instruction comprises: The second instruction is sent to the third converter station, so that the third converter station closes the first grounding switch in response to the second instruction.

6. The grounding conversion method according to claim 5, characterized in that: The grounding device of the second grounding switch is arranged outside the area of ​​the third converter station; The determining that the first current value satisfies the first preset condition and determining the second instruction according to the conversion threshold of the second converter station includes: Determining that the first current value satisfies the first preset condition, and determining that the conversion threshold satisfies a second conversion threshold condition, and determining the second instruction according to the conversion threshold; The sending the second instruction to the third converter station so that the third converter station closes the grounding switch of the third converter station in response to the second instruction comprises: The second instruction is sent to the third converter station, so that the third converter station closes the second grounding switch in response to the second instruction.

7. The grounding conversion method according to claim 6, characterized in that: The sending of a fifth instruction to the third converter station so that the third converter station disconnects the grounding switch in response to the fifth instruction comprises: The fifth instruction is sent to the third converter station, so that the third converter station opens the first grounding switch or the second grounding switch in response to the fifth instruction.

8. A grounding conversion method for a split-address cascade flow transmission system, characterized in that: The grounding switch of the third converter station includes a first grounding switch and a second grounding switch, wherein the grounding device of the first grounding switch is arranged in the area of ​​the third converter station, and the grounding device of the second grounding switch is arranged outside the area of ​​the third converter station; The grounding conversion method comprises: collecting a third current value of the converter of the second converter station; Determining a first current value of a first switch of the second converter station according to the third current value; receiving a first instruction from a first converter station; According to the first instruction, it is determined that the first current value meets a first preset condition, and then a second instruction is sent to the third converter station, so that the third converter station closes the second grounding switch in response to the second instruction; In response to a third instruction from the third converter station, sending a sixth instruction to the second converter station, so that the second converter station closes the first transfer switch in response to the sixth instruction; collecting a second current value of the first conversion switch; If it is determined that the second current value satisfies the second preset condition, a fourth instruction is sent to the second converter station, so that the second converter station disconnects the second transfer switch of the second converter station in response to the fourth instruction.

9. The grounding conversion method according to claim 8, characterized in that: After determining that the second current value satisfies the second preset condition, sending a fourth instruction to the second converter station so that the second converter station disconnects the second transfer switch of the second converter station in response to the fourth instruction, the grounding transfer switch method further includes: The fifth instruction is sent to the third converter station, so that the third converter station opens the second grounding switch in response to the fifth instruction.

10. A grounding conversion system for a cascaded DC power transmission system, characterized in that: The ground conversion system comprises: A processing module receives a first instruction from a first converter station; a collection module, receiving the first instruction transmitted by the processing module, and collecting a first current value of a first transfer switch of a second converter station according to the first instruction; The processing module further receives and determines the first current value, and if it is determined that the first current value satisfies a first preset condition, sends a second instruction to the third converter station, so that the third converter station closes the grounding switch of the third converter station in response to the second instruction, and the processing module receives the third instruction from the third converter station; The acquisition module receives the third instruction transmitted by the processing module, and acquires the second current value of the first conversion switch according to the third instruction; The processing module also determines that the second current value satisfies a second preset condition, and then sends a fourth instruction to the second converter station, so that the second converter station disconnects the second transfer switch of the second converter station in response to the fourth instruction.

11. The ground transfer system according to claim 10, characterized in that: The processing module further sends a fifth instruction to the third converter station, so that the third converter station opens the grounding switch in response to the fifth instruction.

12. The ground transfer system according to claim 11, characterized in that: The first instruction includes a switching threshold of the second converter station; The processing module also determines that the first current value satisfies the first preset condition, determines the second instruction according to the conversion threshold of the second converter station, and the processing module also sends the second instruction to the third converter station so that the third converter station closes the grounding switch of the third converter station in response to the second instruction.

13. The ground transfer system according to claim 12, characterized in that: The grounding switch of the third converter station includes a first grounding switch and a second grounding switch; The processing module also determines that the first current value satisfies the first preset condition, and then sends a second instruction to the third converter station, so that the third converter station closes the first grounding switch or the second grounding switch in response to the second instruction.

14. The ground transfer system according to claim 13, characterized in that: The grounding device of the first grounding switch is arranged in the area of ​​the third converter station; The processing module also determines that the first current value satisfies the first preset condition, and determines that the conversion threshold satisfies the first conversion threshold condition, then determines the second instruction according to the conversion threshold, and the processing module also sends the second instruction to the third converter station so that the third converter station closes the first grounding switch in response to the second instruction.

15. The ground transfer system according to claim 14, characterized in that: The grounding device of the second grounding switch is arranged outside the area of ​​the third converter station; The processing module determines that the first current value satisfies the first preset condition and determines that the conversion threshold satisfies the second conversion threshold condition, then determines the second instruction according to the conversion threshold, and the processing module sends the second instruction to the third converter station so that the third converter station closes the second grounding switch in response to the second instruction.

16. The ground transfer system according to claim 11, characterized in that: The grounding switch of the third converter station includes a first grounding switch and a second grounding switch, the grounding device of the first grounding switch is arranged in the area of ​​the third converter station, and the grounding device of the second grounding switch is arranged outside the area of ​​the third converter station; The acquisition module further acquires a third current value of the converter of the second converter station; The processing module further determines the first current value according to the third current value, and determines that the first current value satisfies the first preset condition, then the processing module sends the second instruction to the third converter station, so that the third converter station closes the second grounding switch in response to the second instruction, and the processing module sends the sixth instruction to the second converter station in response to the third instruction from the third converter station, so that the second converter station closes the first transfer switch in response to the sixth instruction; The acquisition module also acquires the second current value of the first conversion switch.

17. The ground transfer system according to claim 10 or 16, characterized in that: The processing module further sends the fifth instruction to the third converter station, so that the third converter station disconnects the first grounding switch or the second grounding switch in response to the fifth instruction.

18. A non-volatile computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the grounding conversion method of the divided-address cascaded direct current transmission system according to any one of claims 1 to 7 is implemented.

19. An electronic device, characterized in that: include: one or more processors; A storage device for storing one or more programs; When the one or more programs are executed by the one or more processors, the one or more processors implement the grounding conversion method for a distributed cascaded direct current transmission system as described in any one of claims 1 to 7.

20. A computer program product, characterized in that The invention comprises a computer program stored on a computer-readable storage medium, wherein the computer program comprises program instructions, and when the program instructions are executed by a computer, the computer is caused to execute the grounding conversion method for a cascaded direct current transmission system according to any one of claims 1 to 7.

21. A non-volatile computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the grounding conversion method of the split-address cascaded direct current transmission system as described in any one of claims 8 to 9 is implemented.

22. An electronic device, characterized in that: include: one or more processors; A storage device for storing one or more programs; When the one or more programs are executed by the one or more processors, the one or more processors implement the grounding conversion method for the distributed cascaded direct current transmission system as described in any one of claims 8 to 9.

23. A computer program product, characterized in that The invention comprises a computer program stored on a computer-readable storage medium, wherein the computer program comprises program instructions, and when the program instructions are executed by a computer, the computer is caused to execute the grounding conversion method for a cascaded direct current transmission system according to any one of claims 8 to 9.

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