An ultra-high voltage multi-terminal direct current transmission line ice melting electrical wiring and control method thereof

Abstract

The present invention relates to the field of high-voltage direct current (HVDC) transmission technology, and more particularly to an electrical wiring arrangement for de-icing an ultra-high voltage multi-terminal direct current (UHV) transmission line and a control method thereof. The arrangement comprises first to seventh de-icing disconnectors and a plurality of converter stations. The converter stations include a first converter station, a second converter station, and a third converter station connected via a DC line. The third converter station includes a positive transmission line system, a negative transmission line system, a grounding electrode, a positive DC line, a negative DC line, and first to twenty-second disconnectors. The converter station utilizes the existing disconnector design and the addition of seven de-icing disconnectors to implement switching between converter station operating states and de-icing functions for parallel operation of dual valve groups under different operating states. The present invention achieves de-icing under various operating states of the multi-terminal DC transmission line by connecting the seven de-icing disconnectors, effectively addressing the de-icing requirements of long-distance DC transmission lines, improving the operational reliability of the transmission lines, and reducing costs.

Description

Technical Field

[0001] The present invention relates to the technical field of high-voltage direct current (HVDC) transmission, and in particular to an electrical connection for ice melting in an ultra-high voltage multi-terminal direct current (UHV) transmission line and a control method thereof. Background Art

[0002] At present, the only ultra-high voltage multi-terminal direct current (UHV) line in operation in China is the Kunbei-Liubei-Longmen three-terminal flexible direct current (UHV) line, with a voltage level of ±800 kV and a transmission capacity of 8,000 MW. However, this DC transmission line is not yet equipped with ice-melting equipment. The ultra-high voltage multi-terminal direct current (UHV) system can achieve long-distance, large-capacity power transmission between multiple sending and receiving terminals. Compared with the construction of multiple two-terminal direct current lines, ultra-high voltage direct current (UHVDC) can not only save transmission corridors more effectively, but also reduce system losses, improve the economic efficiency of power transmission and the transmission capacity of the power grid, which is conducive to long-distance power transmission. Ultra-high voltage generally refers to voltage levels of ±800 kV and above for direct current and 1,000 kV and above for alternating current.

[0003] However, UHVDC transmission lines are long and easily cross multiple heavily iced areas. Once a transmission line is severely iced, it will threaten the safe operation of the transmission line and the power grids at both ends of the line. Traditional ice melting (de-icing) methods for iced lines require shutting down the DC line. Specific ice melting methods include the following:

[0004] Option 1: Manual mechanical de-icing. Due to the long distance of the UHV line, mechanical de-icing takes too long and cannot be done quickly, thus affecting power transmission.

[0005] Option 2: Install a fixed ice-melting device in a converter station at one end of the line to provide ice-melting current for the line. Due to limitations such as the economic efficiency of the ice-melting device power, this method is only suitable for short lines and is not suitable for long DC lines.

[0006] Option 3: Add power supply points outside the ice-covered lines to melt the ice; due to the long distance of the UHV lines, it is difficult to ensure that there are suitable external power supply points along the lines, and the actual operation is difficult.

[0007] Option 4: De-icing by operating the converter stations with DC at both ends. Change the DC side electrical connections in the converter stations at both ends of the DC line, and melt the ice by operating the DC in parallel with valve groups. This de-icing method can adopt a symmetrical single-pole or single-pole metal return DC operation mode. The UHV converter station adopts a design with four valve groups in series. When using this technology, two valve groups are short-circuited and the other two valve groups are connected in parallel. Under the condition of the rated power of the valve group, at least twice the rated current can be generated on the line, and this large current is used to melt the ice.

[0008] In ultra-high voltage direct current (UHVDC) projects for long-distance transmission lines, the first three solutions mentioned above are difficult to apply in practice. Solution 4 has been applied to multiple two-terminal DC projects at home and abroad. However, when the electrical wiring of Solution 4 is applied to converter station systems with at least three terminals, the circuit cannot be conducted, and it cannot meet the operating requirements of at least three-terminal DC lines in different states. In addition to meeting the function of parallel connection of dual valve groups, the de-icing wiring of DC lines with more than two terminals also requires various working and operating states. Therefore, it is urgent to propose an electrical wiring topology characteristic and operating requirements of ultra-high voltage multi-terminal DC, which is suitable for de-icing electrical wiring of converter stations for multi-terminal DC. Summary of the Invention

[0009] The present invention provides an electrical wiring for de-icing of a UHV multi-terminal DC transmission line and a control method thereof, which solves the technical problem that traditional de-icing electrical wiring is only applicable to two-terminal DC and cannot meet the de-icing requirements of UHV multi-terminal DC converter stations.

[0010] In order to solve the above technical problems, the present invention provides an ultra-high voltage multi-terminal direct current transmission line ice melting electrical wiring and a control method thereof.

[0011] In a first aspect, the present invention provides an ultra-high voltage multi-terminal direct current transmission line ice-melting electrical connection, comprising first to seventh ice-melting disconnectors and a plurality of converter stations, wherein the converter stations include a first converter station, a second converter station, and a third converter station connected by direct current lines, wherein the third converter station includes a positive transmission line system, a negative transmission line system, a grounding electrode, a positive direct current line, a negative direct current line, and first to twenty-second disconnectors;

[0012] The positive output terminal of the first converter station is connected to the negative DC line through the third and fourth ice-melting disconnectors connected in series. The positive output terminal of the first converter station is connected to the positive output terminal of the second converter station through the seventh ice-melting disconnector. The negative output terminal of the first converter station is connected to the negative output terminal of the second converter station through the sixth ice-melting disconnector.

[0013] The positive power transmission line system includes a positive high-end valve group module and a positive low-end valve group module connected in series, wherein the positive high-end valve group module includes a positive high-end converter valve group, and the positive low-end valve group module includes a positive low-end converter valve group;

[0014] The negative transmission line system includes a first circuit breaker, a negative high-end valve group module, and a negative low-end valve group module; the negative high-end valve group module and the negative low-end valve group module are connected in series via a first ice-melting isolation switch, and the negative low-end valve group module is connected to the negative output terminal of the first converter station via a first circuit breaker and a fifth ice-melting isolation switch in sequence;

[0015] The negative high-end valve group module includes a negative high-end converter valve group, a second circuit breaker and a first isolating switch connected in parallel; the negative low-end valve group module includes a negative low-end converter valve group, a third circuit breaker and a second isolating switch connected in parallel; one end of the second ice-melting isolating switch is connected to the common end of the negative high-end converter valve group and the second circuit breaker, and the other end of the second ice-melting isolating switch is connected to the common end of the first ice-melting isolating switch and the second isolating switch.

[0016] In a further embodiment, the negative high-side valve assembly module further includes a third isolating switch, a fourth isolating switch, a fifth isolating switch, and a sixth isolating switch. The two ends of the first isolating switch are respectively connected to the fourth isolating switch and the fifth isolating switch and then connected in parallel with the second circuit breaker. The negative high-side valve assembly module is connected to the negative DC line through the third isolating switch and the sixth isolating switch.

[0017] The negative electrode low-end valve group module also includes a seventh isolating switch and an eighth isolating switch, wherein two ends of the second isolating switch are respectively connected to the seventh isolating switch and the eighth isolating switch and then connected in parallel with the third circuit breaker.

[0018] In a further embodiment, the negative transmission line system further includes a ninth isolating switch, a tenth isolating switch, a negative high-end converter transformer connected to the negative high-end valve group module, and a negative low-end converter transformer connected to the negative low-end valve group module;

[0019] The negative low-end valve group module is connected to one end of the tenth isolating switch through the first circuit breaker, and the other end of the tenth isolating switch is connected to the grounding electrode. The negative low-end valve group module is also connected to one end of the ninth isolating switch through the first circuit breaker.

[0020] In a further embodiment, the positive transmission line system further includes an eleventh disconnector, a twelfth disconnector, a fourth circuit breaker, a positive high-end converter transformer connected to the positive high-end valve group module, and a positive low-end converter transformer connected to the positive low-end valve group module;

[0021] The positive high-end valve group module also includes a fifth circuit breaker, a thirteenth isolating switch, a fourteenth isolating switch, a fifteenth isolating switch, a sixteenth isolating switch, and a seventeenth isolating switch. The positive high-end converter valve group and the fifth circuit breaker are connected in parallel, and the two ends of the fifteenth isolating switch are respectively connected to the fourteenth isolating switch and the sixteenth isolating switch, and then connected in parallel with the fifth circuit breaker. The positive high-end valve group module is connected to the positive DC line through the thirteenth isolating switch and the seventeenth isolating switch.

[0022] The positive low-end valve group module further includes a sixth circuit breaker, an eighteenth isolating switch, a nineteenth isolating switch, and a twentieth isolating switch. The positive low-end converter valve group and the sixth circuit breaker are connected in parallel, and both ends of the eighteenth isolating switch are respectively connected to the nineteenth isolating switch and the twentieth isolating switch, and then connected in parallel with the sixth circuit breaker.

[0023] The positive low-end valve group module is connected to one end of the eleventh isolating switch through the fourth circuit breaker, and the other end of the eleventh isolating switch is connected to the grounding electrode. The positive low-end valve group module is also connected to one end of the twelfth isolating switch through the fourth circuit breaker.

[0024] In a further embodiment, the positive DC line and the negative DC line are connected via a twenty-first isolating switch and a twenty-second isolating switch.

[0025] In a further embodiment, an ice melting control module is further included, wherein the ice melting control module is configured to control the first ice melting isolation switch, the second ice melting isolation switch, the third ice melting isolation switch, the fourth ice melting isolation switch, and the fifth ice melting isolation switch during ice melting operation of the converter station, so as to connect the positive high-side converter valve group and the negative high-side converter valve group in parallel;

[0026] The ice-melting control module is further configured to control the sixth ice-melting isolating switch and the seventh ice-melting isolating switch so as to switch the multi-terminal direct current transmission line to different operating states.

[0027] In a second aspect, the present invention provides a method for controlling the electrical wiring for de-icing of a UHV multi-terminal DC transmission line, the method being used to control the electrical wiring for de-icing of the UHV multi-terminal DC transmission line to switch between the following different operating states:

[0028] When receiving an operating state instruction to switch to double-terminal DC operation with only the first converter station and the second converter station in operation, the first converter station and the second converter station are controlled to be put into operation, and the sixth ice-melting disconnector, the seventh ice-melting disconnector, the sixth disconnector, and the seventeenth disconnector are disconnected;

[0029] When receiving an operating state instruction to switch to double-terminal DC operation with only the first and third converter stations in operation, the first and third converter stations are controlled to be put into operation, the sixth and seventh ice-melting disconnectors are opened, and the sixth and seventeenth disconnectors are closed;

[0030] When receiving the operating state of switching to double-terminal DC operation and only the second converter station and the third converter station are in operation, the second converter station and the third converter station are controlled to be put into operation, and the sixth ice-melting disconnector, the seventh ice-melting disconnector, the sixth disconnector and the seventeenth disconnector are closed;

[0031] When receiving the operating state instruction to switch to multi-terminal DC operation, the first converter station, the second converter station and the third converter station are controlled to be put into operation, and the sixth ice-melting disconnector, the seventh ice-melting disconnector, the sixth disconnector and the seventeenth disconnector are closed.

[0032] In a further implementation scheme, when the third converter station is put into operation, if a parallel control instruction for the ice-melting valve group is received, the first ice-melting disconnector, the fourth disconnector, the seventh disconnector, the eighth disconnector, the ninth disconnector, the twelfth disconnector, the fifteenth disconnector, the nineteenth disconnector, the twentieth disconnector, the twenty-first disconnector and the twenty-second disconnector are controlled to be disconnected, and at the same time, the second ice-melting disconnector, the third ice-melting disconnector, the fourth ice-melting disconnector, the fifth ice-melting disconnector, the first disconnector, the second disconnector, the third disconnector, the fifth disconnector, the tenth disconnector, the eleventh disconnector, the thirteenth disconnector, the fourteenth disconnector, the sixteenth disconnector and the eighteenth disconnector are controlled to be closed.

[0033] In a third aspect, the present invention also provides a computer device comprising a processor and a memory, wherein the processor is connected to the memory, the memory is used to store a computer program, and the processor is used to execute the computer program stored in the memory so that the computer device performs the steps of implementing the above method.

[0034] In a fourth aspect, the present invention further provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the above method are implemented.

[0035] The present invention provides an electrical wiring system for de-icing ultra-high voltage multi-terminal direct current (UHV) transmission lines and a control method thereof. By adding seven de-icing disconnectors, the de-icing electrical wiring system overcomes the problem that conventional de-icing electrical wiring systems are only suitable for two-terminal direct current (DC) transmission lines and cannot meet the de-icing requirements of UHV multi-terminal direct current (DC) converter stations. This de-icing electrical wiring system implements the de-icing function of parallel operation of dual-valve groups in multi-terminal DC transmission lines and can simultaneously switch the operating state of the converter station in conjunction with existing disconnectors. Compared to existing technologies, this de-icing electrical wiring system not only implements the de-icing function of parallel operation of dual-valve groups in multi-terminal DC transmission lines but also enables switching the operating state of the converter station with only a few switches. This de-icing electrical wiring system is adaptable to various operating conditions and offers high reliability, flexibility, and cost-effectiveness. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a schematic diagram of the electrical wiring structure for ice melting on a UHV multi-terminal DC transmission line provided by an embodiment of the present invention;

[0037] Figure 2 This is a schematic diagram of ice melting wiring for the three-terminal DC first and last converter stations provided by an embodiment of the present invention;

[0038] Figure 3 Schematic diagram of a multi-terminal direct current transmission system with a ring structure provided by an embodiment of the present invention;

[0039] Figure 4 It is a structural diagram of a computer device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0040] The following describes the embodiments of the present invention in detail with reference to the accompanying drawings. The embodiments are provided for illustrative purposes only and are not to be construed as limiting the present invention. The accompanying drawings are provided for reference and illustration only and do not constitute a limitation on the scope of protection of the present invention. Many changes may be made to the present invention without departing from the spirit and scope of the present invention.

[0041] refer to Figure 1 The embodiment of the present invention provides an ultra-high voltage multi-terminal direct current transmission line ice melting electrical wiring, which can be applied to a two-terminal or multi-terminal direct current transmission system, wherein the multi-terminal direct current transmission system includes a direct current transmission system with at least three converter stations, such as Figure 1 As shown, it includes: first to seventh ice-melting disconnectors Q51~Q57 and several converter stations, wherein the converter stations include a first converter station A, a second converter station B and a third converter station C connected by DC lines, and the third converter station C includes a positive transmission line system, a negative transmission line system, a grounding electrode, a positive DC line 11 and a negative DC line 12.

[0042] Among them, the third converter station C is connected to the +800kV line of the first converter station A and the second converter station B through the positive DC line 11, and the third converter station is connected to the -800kV line of the first converter station A and the second converter station B through the negative DC line 12; in this embodiment, the positive output terminal of the first converter station A is connected to the negative DC line 12 through the third ice-melting disconnector Q53 and the fourth ice-melting disconnector Q54 connected in series, the positive output terminal of the first converter station A is connected to the positive output terminal of the second converter station B through the seventh ice-melting disconnector Q57, and the negative output terminal of the first converter station A is connected to the negative output terminal of the second converter station B through the sixth ice-melting disconnector Q56.

[0043] In one embodiment, the negative transmission line system includes a first circuit breaker Q7, a ninth isolating switch Q35, a tenth isolating switch Q32, a negative high-end valve group module 131, a negative low-end valve group module 132, a negative high-end converter transformer connected to the negative high-end valve group module 131, and a negative low-end converter transformer connected to the negative low-end valve group module 132; the negative high-end valve group module 131 and the negative low-end valve group module 132 are connected in series through a first ice-melting isolating switch Q51, and the negative low-end valve group module is connected to the negative output terminal of the first converter station through the first circuit breaker Q7 and the fifth ice-melting isolating switch Q55 in sequence; wherein, pole 1 is a positive line and pole 2 is a negative line.

[0044] The negative high-end valve group module includes a third isolating switch Q21, a fourth isolating switch Q22, a fifth isolating switch Q24, a sixth isolating switch Q29, a negative high-end converter valve group, a second circuit breaker Q4 and a first isolating switch Q23, wherein the negative high-end converter valve group and the second circuit breaker Q4 are connected in parallel, and the two ends of the first isolating switch Q23 are respectively connected to the fourth isolating switch Q22 and the fifth isolating switch Q24 and then connected in parallel with the second circuit breaker Q4. In this embodiment, the negative high-end valve group module is connected to the negative DC line through the third isolating switch Q21 and the sixth isolating switch Q29.

[0045] The negative low-end valve group module includes a seventh isolating switch Q25, an eighth isolating switch Q27, a negative low-end converter valve group, a third circuit breaker Q3 and a second isolating switch Q26, wherein the negative low-end converter valve group and the third circuit breaker Q3 are connected in parallel, and the two ends of the second isolating switch Q26 are respectively connected to the seventh isolating switch Q25 and the eighth isolating switch Q27 and then connected in parallel with the third circuit breaker Q3; the negative low-end valve group module is connected to one end of the tenth isolating switch Q32 through the first circuit breaker Q7, and the other end of the tenth isolating switch Q32 is connected to the ground electrode. The negative low-end valve group module is also connected to one end of the ninth isolating switch Q35 through the first circuit breaker Q7.

[0046] In this embodiment, one end of the second ice-melting isolation switch Q52 is connected to the common end of the negative high-side converter valve group and the second circuit breaker Q4, and the other end of the second ice-melting isolation switch Q52 is connected to the common end of the first ice-melting isolation switch Q51 and the second isolation switch Q26.

[0047] Compared with the prior art, this embodiment maintains the voltage direction of the negative high-side converter valve group during ice melting (reverse wiring of the valve group) by setting Q51 and Q52, so that the current passes through Q23-Q24-negative high-side converter valve group-Q52 in sequence, and Q51 and Q22 are disconnected, saving a branch line and saving the investment and space occupied by the converter station.

[0048] In one embodiment, the positive power transmission line system includes an eleventh isolating switch Q31, a twelfth isolating switch Q34, a fourth circuit breaker Q6, a positive high-end valve group module 141, a positive low-end valve group module 142, a positive high-end converter transformer connected to the positive high-end valve group module, and a positive low-end converter transformer connected to the positive low-end valve group module, wherein the positive high-end valve group module 141 and the positive low-end valve group module 142 are connected in series.

[0049] The positive high-end valve group module includes a fifth circuit breaker Q1, a thirteenth isolating switch Q11, a fourteenth isolating switch Q12, a fifteenth isolating switch Q13, a sixteenth isolating switch Q14, a seventeenth isolating switch Q19 and a positive high-end converter valve group, wherein the positive high-end converter valve group and the fifth circuit breaker Q1 are connected in parallel, and the two ends of the fifteenth isolating switch Q13 are respectively connected to the fourteenth isolating switch Q12 and the sixteenth isolating switch Q14 and then connected in parallel with the fifth circuit breaker Q1; the positive high-end valve group module is connected to the positive DC line through the thirteenth isolating switch Q11 and the seventeenth isolating switch Q19.

[0050] The positive low-end valve group module includes a sixth circuit breaker Q2, an eighteenth isolating switch Q16, a nineteenth isolating switch Q15, a twentieth isolating switch Q17 and a positive low-end converter valve group, wherein the positive low-end converter valve group and the sixth circuit breaker Q2 are connected in parallel, and the two ends of the eighteenth isolating switch Q16 are respectively connected to the nineteenth isolating switch Q15 and the twentieth isolating switch Q17 and then connected in parallel with the sixth circuit breaker Q2; the positive low-end valve group module is connected to one end of the eleventh isolating switch Q31 through the fourth circuit breaker Q6, and the other end of the eleventh isolating switch Q31 is connected to the ground electrode. The positive low-end valve group module is also connected to one end of the twelfth isolating switch Q34 through the fourth circuit breaker Q6.

[0051] The electric connection for ice melting of a UHV multi-terminal DC transmission line provided in this embodiment further includes: a twenty-first isolating switch Q18 and a twenty-second isolating switch Q28; the positive DC line and the negative DC line are connected via the twenty-first isolating switch Q18 and the twenty-second isolating switch Q28, and the other end of the ninth isolating switch Q35 and the other end of the twelfth isolating switch Q34 are connected to a common end of the twenty-first isolating switch Q18 and the twenty-second isolating switch Q28.

[0052] The electric wiring for de-icing an ultra-high voltage multi-terminal direct current transmission line provided in this embodiment further includes an de-icing control module, which is configured to control the first de-icing disconnector, the second de-icing disconnector, the third de-icing disconnector, the fourth de-icing disconnector, and the fifth de-icing disconnector during de-icing operation at the converter station, so as to connect the positive high-side converter valve group and the negative high-side converter valve group in parallel.

[0053] The ice-melting control module is further configured to control the sixth ice-melting isolating switch and the seventh ice-melting isolating switch so as to switch the multi-terminal direct current transmission line to different operating states.

[0054] Specifically, the ice melting control module is used to control the first ice melting isolation switch, the second ice melting isolation switch, the third ice melting isolation switch, the fourth ice melting isolation switch, and the fifth ice melting isolation switch during ice melting operation of the converter station, so as to connect the positive high-end converter valve group and the negative high-end converter valve group in parallel. Specifically,

[0055] When the third converter station is put into operation, if a parallel control instruction for controlling the ice-melting valve group is received, it means that the converter station needs to operate by ice-melting. At this time, the first ice-melting disconnector Q51, the fourth disconnector Q22, the seventh disconnector Q25, the eighth disconnector Q27, the ninth disconnector Q35, the twelfth disconnector Q34, the fifteenth disconnector Q13, the nineteenth disconnector Q15, the twentieth disconnector Q17, the twenty-first disconnector Q18 and the twenty-second disconnector Q28 are controlled to be opened, and the second ice-melting disconnector Q51, the fourth ice-melting disconnector Q51, the fifth ice-melting disconnector Q51, the second disconnector Q26, the third disconnector Q21, the fifth disconnector Q24, the tenth disconnector Q32, the eleventh disconnector Q31, the thirteenth disconnector Q11, the fourteenth disconnector Q12, the sixteenth disconnector Q14 and the eighteenth disconnector Q16 are controlled to be closed.

[0056] The ice melting control module is further configured to control the sixth ice melting isolation switch and the seventh ice melting isolation switch to switch the multi-terminal DC transmission line to different operating states, specifically:

[0057] When receiving an operating state instruction to switch to double-terminal DC operation with only the first converter station and the second converter station in operation, the first converter station and the second converter station are controlled to be put into operation, and the sixth ice-melting disconnector, the seventh ice-melting disconnector, the sixth disconnector Q29 and the seventeenth disconnector Q19 are disconnected;

[0058] When receiving an operating state instruction to switch to double-terminal DC operation with only the first and third converter stations in operation, the first and third converter stations are controlled to be put into operation, the sixth and seventh ice-melting disconnectors are opened, and the sixth and seventh disconnectors Q29 and Q19 are closed;

[0059] When receiving the operating status of switching to double-terminal DC operation and only the second converter station and the third converter station are in operation, the second converter station and the third converter station are controlled to be put into operation, and the sixth ice-melting disconnector, the seventh ice-melting disconnector, the sixth disconnector Q29 and the seventeenth disconnector Q19 are closed;

[0060] When the operating state instruction to switch to multi-terminal DC operation is received, the first converter station, the second converter station and the third converter station are controlled to be put into operation, and the sixth ice-melting disconnector, the seventh ice-melting disconnector, the sixth disconnector Q29 and the seventeenth disconnector Q19 are closed.

[0061] In this embodiment, the first to seventh ice-melting isolating switches Q51 to Q57 are added, so that the first ice-melting isolating switch Q51, the second ice-melting isolating switch Q52, the third ice-melting isolating switch Q53, the fourth ice-melting isolating switch Q54 and the fifth ice-melting isolating switch Q55 are used to connect the positive high-end valve group module and the negative high-end valve group module in parallel during ice melting, and the sixth ice-melting isolating switch Q56 and the seventh ice-melting isolating switch Q57 are used to cooperate with the existing isolating switches to realize the conversion of different working states of the converter station.

[0062] It should be noted that the first ice-melting disconnector Q51 is in a normally closed state when not in ice-melting operation, and is in a normally open state in other operating conditions; the sixth ice-melting disconnector Q56 and the seventh ice-melting disconnector Q57 are in a normally open state when not in ice-melting operation. The switch opening and closing and current paths in different operating conditions of the converter station are specifically shown as follows:

[0063] State 1: Double-ended DC operation, stations A and B are operating, and station C is out of service:

[0064] Close the disconnectors Q41 to Q44, disconnect Q56, Q57, Q19 and Q29, and the third converter station C is bypassed and not connected to the line.

[0065] State 2: Double-ended DC operation, stations A and C are in operation, and station B is out of service:

[0066] Close Q41, Q42, Q19, and Q29, and open Q43, Q44, Q56, and Q57.

[0067] If the third converter station C is put into de-icing operation, Q51, Q22, Q25, Q27, Q13, Q15, Q17, Q34, Q35, Q18, and Q28 will be disconnected; and Q52 to Q55, Q21, Q23, Q24, Q26, Q31, Q32, Q11, Q12, Q14, and Q16 will be closed to connect the de-icing valve groups in parallel. At this time, the current path of this part of the circuit is:

[0068] Positive valve group current path: +800kV line—Q41—Q19—Q11—Q12—pole 1 high-end valve group—Q14—Q16—Q31—Q32—Q55—-800kV line;

[0069] Negative valve group current path: +800kV line—Q53—Q54—Q29—Q21—Q23—Q24—pole 2 high-end valve group—Q52—Q26—Q55—-800kV line.

[0070] It should be noted that as long as the third converter station C is put into ice-melting operation, the opening and closing conditions of these switches will be the same and will not be repeated in the subsequent status description.

[0071] State 3: Double-ended DC operation, B and C are running, and A is stopped:

[0072] The switch closure for state transition: Q41, Q42, Q56, Q57, Q19, and Q29 are closed, and Q43 and Q44 are opened. At this time, the disconnector on the line side of the first converter station A is open. The ice-melting current path is:

[0073] Positive valve group current path: Pole 1 line (+800kV line) - Q57 - Q41 - Q19 - Q11 - Q12 - Pole 1 high-end valve group - Q14 - Q16 - Q31 - Q32 - Q55 - Q56 - Pole 2 line;

[0074] Negative valve group current path: pole 1 line—Q57—Q53—Q54—Q29—Q21—Q23—Q24—pole 2 high-end valve group—Q52—Q26—Q55—Q56—pole 2 line.

[0075] State 4: Three-terminal DC operation:

[0076] Switch closure conditions for state transition: Q41, Q42, Q56, Q57, Q19, Q29 are closed, and Q43 and Q44 are opened.

[0077] It should be noted that its ice-melting current path is the same as the ice-melting current path in state two. It should be noted that, during ice melting, the current from the third converter station C to the first converter station A does not pass through Q55 and Q56, and the current from the third converter station to the second converter station B passes through Q55 and Q56.

[0078] This embodiment isolates the converter station operating state switching function (required for both de-icing and de-icing) from the de-icing function (implementing the dual-valve group parallel connection function). The above analysis indicates that the switch opening and closing conditions for implementing the de-icing function in various operating states of the three-terminal DC system are completely consistent, while state switching requires operating a small number of switches in the wiring. Therefore, the de-icing wiring of this embodiment offers the advantages of convenience and reliability, avoiding excessive switch operations and reducing the possibility of erroneous operation.

[0079] It should be noted that if Figure 2 As shown, the three-terminal DC head and tail converter stations can also adopt the ice-melting wiring of this embodiment, and this wiring can also be directly used in two-terminal DC.

[0080] The present invention can also be applied to a multi-terminal DC transmission system with a ring structure, and can also be applied to a flexible DC distribution network, user new energy access, etc. The multi-terminal DC transmission system with a ring structure is as follows: Figure 3 shown.

[0081] This embodiment provides an electrical wiring system for de-icing ultra-high voltage, multi-terminal DC transmission lines. By providing seven de-icing disconnectors, the de-icing system implements de-icing functionality and operational state switching under various operating conditions of a two-terminal or multi-terminal DC transmission system. Compared to existing technologies, the de-icing electrical wiring system provided in this embodiment not only implements independent operational state switching and de-icing function switching, improving operational convenience and avoiding inoperability, but also improves valve block reverse wiring technology, saving equipment investment and floor space. It effectively addresses the de-icing needs of long-distance DC transmission lines and enhances their operational reliability.

[0082] In one embodiment, the present invention provides a method for controlling ice-melting electrical wiring for a UHV multi-terminal DC transmission line, for controlling the switching of the ice-melting electrical wiring for the UHV multi-terminal DC transmission line between the following different operating states. The method specifically includes:

[0083] When receiving an operating state instruction to switch to double-terminal DC operation with only the first and second converter stations in operation, the first and second converter stations are controlled to be put into operation, and the sixth ice-melting disconnector Q56, the seventh ice-melting disconnector Q57, the sixth disconnector Q29, and the seventeenth disconnector Q19 are disconnected;

[0084] When receiving the operating state instruction to switch to double-terminal DC operation with only the first and third converter stations in operation, the first and third converter stations are controlled to be put into operation, the sixth and seventh ice-melting disconnectors Q56 and Q57 are opened, and the sixth and seventeenth disconnectors Q29 and Q19 are closed;

[0085] When receiving the operating status of switching to double-terminal DC operation and only the second converter station and the third converter station are in operation, the second converter station and the third converter station are controlled to be put into operation, and the sixth ice-melting disconnector Q56, the seventh ice-melting disconnector Q57, the sixth disconnector Q29 and the seventeenth disconnector Q19 are closed;

[0086] When the operating state instruction to switch to multi-terminal DC operation is received, the first converter station, the second converter station and the third converter station are controlled to be put into operation, and the sixth ice-melting disconnector Q56, the seventh ice-melting disconnector Q57, the sixth disconnector Q29 and the seventeenth disconnector Q19 are closed.

[0087] Among them, when the third converter station is put into operation, if the parallel control instruction of the ice-melting valve group is received, the first ice-melting disconnector Q51, the fourth disconnector Q22, the seventh disconnector Q25, the eighth disconnector Q27, the ninth disconnector Q35, the twelfth disconnector Q34, the fifteenth disconnector Q13, the nineteenth disconnector Q15, the twentieth disconnector Q17, the twenty-first disconnector Q18 and the twenty-second disconnector Q28 are controlled to be opened, and the second ice-melting disconnector Q51, the fourth ice-melting disconnector Q51, the fifth ice-melting disconnector Q51, the second disconnector Q26, the third disconnector Q21, the fifth disconnector Q24, the tenth disconnector Q32, the eleventh disconnector Q31, the thirteenth disconnector Q11, the fourteenth disconnector Q12, the sixteenth disconnector Q14 and the eighteenth disconnector Q16 are controlled to be closed.

[0088] It should be noted that the execution order of the above processes should be determined by their functions and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0089] For the specific definition of a method for controlling the electrical wiring of an ultra-high voltage multi-terminal DC transmission line for melting ice, please refer to the above-mentioned definition of the electrical wiring of an ultra-high voltage multi-terminal DC transmission line for melting ice, which will not be repeated here. A person of ordinary skill in the art will appreciate that the various modules and steps described in conjunction with the embodiments disclosed in this application can be implemented in hardware, software, or a combination of both. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0090] An embodiment of the present invention provides a method for controlling de-icing electrical wiring on ultra-high voltage, multi-terminal direct current (UHV) transmission lines. This method, through seven de-icing disconnectors, enables rapid switching of converter station operating states and ice melting, ensuring reliable switching of operating states. It also enables de-icing in parallel operation of two-terminal or multi-terminal DC valve groups, reducing investment and costs. Compared with existing technologies, this method achieves rapid switching of converter station operating states and ice melting by simply controlling the on / off switching of corresponding switch combinations, improving operational convenience and preventing misoperation, thus possessing significant engineering value.

[0091] Figure 4 A computer device provided in an embodiment of the present invention includes a memory, a processor and a transceiver, which are connected via a bus; the memory is used to store a set of computer program instructions and data, and can transmit the stored data to the processor, and the processor can execute the program instructions stored in the memory to perform the steps of the above method.

[0092] The memory may include volatile memory or non-volatile memory, or may include both volatile and non-volatile memory; the processor may be a central processing unit, a microprocessor, an application-specific integrated circuit, a programmable logic device, or a combination thereof. By way of example and not limitation, the programmable logic device may be a complex programmable logic device, a field programmable gate array, a general purpose array logic, or any combination thereof.

[0093] Additionally, the memory may be a physically separate unit or integrated with the processor.

[0094] It can be understood by those skilled in the art that Figure 4 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than shown in the figure, or combine certain components, or have the same component arrangement.

[0095] In one embodiment, the present invention provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the steps of the above method are implemented.

[0096] An embodiment of the present invention provides an ultra-high voltage multi-terminal direct current (HVDC) transmission line de-icing electrical wiring and a control method thereof. The ultra-high voltage multi-terminal direct current (HVDC) transmission line de-icing electrical wiring isolates the converter station operating state switching function (whether de-icing is required) from the de-icing function (implementing the dual-valve group parallel function), thereby implementing de-icing functions under various operating states of two-terminal or multi-terminal DC transmission lines, meeting the de-icing requirements of long-distance DC transmission lines, and improving the operational reliability of the transmission lines.

[0097] In the above embodiments, all or part of the embodiments can be implemented by software, hardware, firmware, or any combination thereof. When implemented using software, all or part of the embodiments can be implemented in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of the present invention are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via a wired (e.g., coaxial cable, optical fiber, digital subscriber line) or wireless (e.g., infrared, wireless, microwave, etc.) method. The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device such as a server or data center that includes one or more available media. The available medium can be a magnetic medium (e.g., a floppy disk, a hard disk, a tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., an SSD).

[0098] Those skilled in the art will understand that all or part of the processes in the above-mentioned embodiment methods can be implemented by instructing related hardware through a computer program. The computer program can be stored in a computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods.

[0099] The above-described embodiments merely represent several preferred implementations of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art could make several improvements and substitutions without departing from the technical principles of the present invention, and these improvements and substitutions should also be considered within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be based on the scope of protection of the claims.

Claims

1. An electrical wiring for melting ice on a UHV multi-terminal DC transmission line, characterized by: The system comprises first to seventh ice-melting disconnectors and a plurality of converter stations, wherein the converter stations include a first converter station, a second converter station, and a third converter station connected by a DC line, and the third converter station includes a positive transmission line system, a negative transmission line system, a grounding electrode, a positive DC line, a negative DC line, and first to twenty-second disconnectors; The positive output terminal of the first converter station is connected to the negative DC line through the third and fourth ice-melting disconnectors connected in series. The positive output terminal of the first converter station is connected to the positive output terminal of the second converter station through the seventh ice-melting disconnector. The negative output terminal of the first converter station is connected to the negative output terminal of the second converter station through the sixth ice-melting disconnector. The positive power transmission line system includes a positive high-end valve group module and a positive low-end valve group module connected in series, wherein the positive high-end valve group module includes a positive high-end converter valve group, and the positive low-end valve group module includes a positive low-end converter valve group; The negative transmission line system includes a first circuit breaker, a negative high-end valve group module, and a negative low-end valve group module; the negative high-end valve group module and the negative low-end valve group module are connected in series via a first ice-melting isolation switch, and the negative low-end valve group module is connected to the negative output terminal of the first converter station via a first circuit breaker and a fifth ice-melting isolation switch in sequence; The negative high-end valve group module includes a negative high-end converter valve group, a second circuit breaker and a first isolating switch connected in parallel; the negative low-end valve group module includes a negative low-end converter valve group, a third circuit breaker and a second isolating switch connected in parallel; one end of the second ice-melting isolating switch is connected to the common end of the negative high-end converter valve group and the second circuit breaker, and the other end of the second ice-melting isolating switch is connected to the common end of the first ice-melting isolating switch and the second isolating switch.

2. The ultra-high voltage multi-terminal direct current transmission line ice-melting electrical wiring according to claim 1, characterized in that: The negative high-end valve assembly module further includes a third isolating switch, a fourth isolating switch, a fifth isolating switch, and a sixth isolating switch. The two ends of the first isolating switch are respectively connected to the fourth isolating switch and the fifth isolating switch and then connected in parallel with the second circuit breaker. The negative high-end valve assembly module is connected to the negative DC line through the third isolating switch and the sixth isolating switch. The negative electrode low-end valve group module also includes a seventh isolating switch and an eighth isolating switch, wherein two ends of the second isolating switch are respectively connected to the seventh isolating switch and the eighth isolating switch and then connected in parallel with the third circuit breaker.

3. The ultra-high voltage multi-terminal direct current transmission line ice-melting electrical wiring according to claim 1, characterized in that: The negative pole transmission line system further includes a ninth isolating switch, a tenth isolating switch, a negative pole high-end converter transformer connected to the negative pole high-end valve group module, and a negative pole low-end converter transformer connected to the negative pole low-end valve group module; The negative low-end valve group module is connected to one end of the tenth isolating switch through the first circuit breaker, and the other end of the tenth isolating switch is connected to the grounding electrode. The negative low-end valve group module is also connected to one end of the ninth isolating switch through the first circuit breaker.

4. The ultra-high voltage multi-terminal direct current transmission line ice-melting electrical wiring according to claim 1, characterized in that: The positive transmission line system further includes an eleventh isolating switch, a twelfth isolating switch, a fourth circuit breaker, a positive high-end converter transformer connected to the positive high-end valve group module, and a positive low-end converter transformer connected to the positive low-end valve group module; The positive high-end valve group module also includes a fifth circuit breaker, a thirteenth isolating switch, a fourteenth isolating switch, a fifteenth isolating switch, a sixteenth isolating switch, and a seventeenth isolating switch. The positive high-end converter valve group and the fifth circuit breaker are connected in parallel, and the two ends of the fifteenth isolating switch are respectively connected to the fourteenth isolating switch and the sixteenth isolating switch, and then connected in parallel with the fifth circuit breaker. The positive high-end valve group module is connected to the positive DC line through the thirteenth isolating switch and the seventeenth isolating switch. The positive low-end valve group module further includes a sixth circuit breaker, an eighteenth isolating switch, a nineteenth isolating switch, and a twentieth isolating switch. The positive low-end converter valve group and the sixth circuit breaker are connected in parallel, and both ends of the eighteenth isolating switch are respectively connected to the nineteenth isolating switch and the twentieth isolating switch, and then connected in parallel with the sixth circuit breaker. The positive low-end valve group module is connected to one end of the eleventh isolating switch through the fourth circuit breaker, and the other end of the eleventh isolating switch is connected to the grounding electrode. The positive low-end valve group module is also connected to one end of the twelfth isolating switch through the fourth circuit breaker.

5. The ultra-high voltage multi-terminal direct current transmission line ice-melting electrical wiring according to claim 1, characterized in that: The positive DC line and the negative DC line are connected via a twenty-first isolating switch and a twenty-second isolating switch.

6. The ultra-high voltage multi-terminal direct current transmission line ice-melting electrical wiring according to claim 1, characterized in that: The converter station further includes an ice melting control module, wherein the ice melting control module is configured to control the first ice melting isolation switch, the second ice melting isolation switch, the third ice melting isolation switch, the fourth ice melting isolation switch, and the fifth ice melting isolation switch during ice melting operation of the converter station, so as to connect the positive high-side converter valve group and the negative high-side converter valve group in parallel; The ice-melting control module is further configured to control the sixth ice-melting isolating switch and the seventh ice-melting isolating switch so as to switch the multi-terminal direct current transmission line to different operating states.

7. A method for controlling ice melting electrical connections in ultra-high voltage multi-terminal direct current transmission lines, characterized in that: Used to control the switching of the ice-melting electrical connection of the ultra-high voltage multi-terminal direct current transmission line according to any one of claims 1 to 6 between the following different operating states: When receiving an operating state instruction to switch to double-terminal DC operation with only the first converter station and the second converter station in operation, the first converter station and the second converter station are controlled to be put into operation, and the sixth ice-melting disconnector, the seventh ice-melting disconnector, the sixth disconnector, and the seventeenth disconnector are disconnected; When receiving an operating state instruction to switch to double-terminal DC operation with only the first and third converter stations in operation, the first and third converter stations are controlled to be put into operation, the sixth and seventh ice-melting disconnectors are opened, and the sixth and seventeenth disconnectors are closed; When receiving the operating state of switching to double-terminal DC operation and only the second converter station and the third converter station are in operation, the second converter station and the third converter station are controlled to be put into operation, and the sixth ice-melting disconnector, the seventh ice-melting disconnector, the sixth disconnector and the seventeenth disconnector are closed; When receiving the operating state instruction to switch to multi-terminal DC operation, the first converter station, the second converter station and the third converter station are controlled to be put into operation, and the sixth ice-melting disconnector, the seventh ice-melting disconnector, the sixth disconnector and the seventeenth disconnector are closed.

8. The method for controlling ice melting electrical connections for a UHV MTDC transmission line according to claim 7, wherein: When the third converter station is put into operation, if the parallel control instruction of the ice-melting valve group is received, the first ice-melting disconnector, the fourth disconnector, the seventh disconnector, the eighth disconnector, the ninth disconnector, the twelfth disconnector, the fifteenth disconnector, the nineteenth disconnector, the twentieth disconnector, the twenty-first disconnector and the twenty-second disconnector are controlled to be disconnected, and the second ice-melting disconnector, the third ice-melting disconnector, the fourth ice-melting disconnector, the fifth ice-melting disconnector, the first disconnector, the second disconnector, the third disconnector, the fifth disconnector, the tenth disconnector, the eleventh disconnector, the thirteenth disconnector, the fourteenth disconnector, the sixteenth disconnector and the eighteenth disconnector are controlled to be closed.

9. A computer device, characterized in that: The computer device comprises a processor and a memory, wherein the processor is connected to the memory, the memory is used to store a computer program, and the processor is used to execute the computer program stored in the memory, so that the computer device performs the method according to any one of claims 7 to 8.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed, the method according to any one of claims 7 to 8 is implemented.

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