Offshore wind power direct transmission converter station connection system and control method and device

Abstract

The application relates to a kind of offshore wind power DC transmission converter station connection systems and control method and equipment, including wind farm, with the AC field module connected with wind farm, transformer module, converter module and DC field module, AC field module includes at least N groups of double-section bus and the connection component of connecting adjacent, first and last two groups or adjacent two groups of double-section bus, transformer module includes the transformer connected with each group of double-section bus, wind farm is provided with the incoming line group connected with each group of double-section bus.This offshore wind power DC transmission converter station connection system can continue to transport corresponding wind farm incoming line power when the fault of a certain bus of AC field module or transformer of transformer module, and can reduce the current flow requirement of equipment, reduce the manufacturing difficulty of equipment, realize the offshore wind power DC transmission without booster station, without additional increase booster station and converter station, reduce construction cost and operation and maintenance cost.

Description

Technical Field

[0001] This invention relates to the field of offshore wind power wiring technology, and in particular to a wiring system, control method and equipment for an offshore wind power DC transmission converter station. Background Technology

[0002] Currently, offshore wind power is generally transmitted to the onshore power grid using two methods: AC transmission and DC transmission. AC transmission is generally suitable for wind power transmission projects with smaller capacity, closer to shore, and shorter transmission distance. The wiring of an offshore wind power system using this AC transmission method is as follows: First, the voltage is collected on the high-voltage side of the wind turbine (e.g., AC 35kV), and then connected to an offshore substation (e.g., stepped up to AC 220kV) via a cable. After stepping up the voltage, it is connected to the onshore substation via an AC cable (AC 220kV). DC transmission is suitable for wind power transmission projects with large capacity, long distance from shore, and long transmission distance. The wiring of offshore wind power systems using this DC transmission method is as follows: First, the high voltage side of the wind turbine (such as AC 35kV) is collected and connected to multiple offshore booster stations (such as AC 35kV to AC 220kV) through multiple cables. Then, it is connected to the offshore converter station through cables, and rectified into DC at the converter station (such as the incoming AC 220kV being transformed into 340kV through a flexible DC transformer, and then into DC 320kV through a converter). Finally, it is connected to the onshore converter station through DC cables.

[0003] The existing offshore wind power AC transmission requires offshore booster stations primarily because the turbine output voltage is relatively low. Boosting the voltage before transmitting AC power to land reduces the number of cables and transmission losses. The existing offshore wind power DC transmission also requires offshore booster stations primarily because DC transmission projects generally have higher DC transmission capacity while the turbine output voltage is lower. Especially when the DC transmission capacity is high and the capacity of the flexible DC transformer in the offshore converter station is also high, if the grid-side voltage of the flexible DC transformer is directly taken as the turbine output voltage, the current in the AC distribution equipment and transformers of the offshore converter station will be extremely high, which is difficult to meet with existing equipment manufacturing capabilities.

[0004] like Figure 6 As shown, existing offshore wind power AC transmission includes AC distribution equipment, a flexible DC transformer connected to the AC distribution equipment, a converter or reactor connected to the flexible DC transformer, and a DC distribution equipment connected to the converter or reactor. The flexible DC transformer consists of two three-phase transformers (one winding on the grid side and one on the valve side) that serve as thermal backups for each other. If one transformer fails, the other transformer can continuously withstand the full rated DC transmission capacity. At this time, the grid-side current is... Taking a DC transmission capacity of 900MM or a transformer capacity of 900MVA as an example, when the incoming line voltage U ac1 =220kV, I ac1 =2.4kA.

[0005] Currently, the rated current of 220kV AC high-voltage distribution equipment for offshore wind power can reach 4kA, and the grid-side windings of transformers connected to existing offshore converter stations can also meet this rated current requirement. However, when the incoming line voltage U of offshore wind power... ac1 =35kV, I ac1 =14.9kA, and based on current equipment manufacturing capabilities, it is impossible to provide corresponding 35kV power distribution equipment and transformers. With the continuous increase in the manufacturing capacity of a single wind turbine, 35kV cables are no longer sufficient to economically collect the power from multiple wind turbines. Higher voltage collection lines (such as 66kV) are needed to improve the overall economic efficiency of the collection scheme. If 66kV is directly connected to the offshore converter station, taking a 900MW DC transmission power as an example, the total AC current is 7.88kA, which the existing AC-side switchgear still cannot meet. Therefore, the existing offshore converter station wiring has the following problems: using DC transmission requires the construction of multiple offshore booster platforms and one offshore converter station platform, resulting in high construction costs and inconvenient operation and maintenance. Without an offshore booster platform, the AC input voltage is low, and the AC equipment in the converter station cannot meet the current requirements. Summary of the Invention

[0006] This invention provides a wiring system, control method, and equipment for an offshore wind power DC transmission converter station. It addresses the technical problems of existing offshore converter stations using DC transmission, which require the construction of multiple step-up substations and converter stations, resulting in high costs and maintenance difficulties; and the low AC input voltage and difficulty in meeting the current carrying requirements of the converter station's AC equipment when no offshore step-up substation platform is constructed.

[0007] To achieve the above objectives, the embodiments of the present invention provide the following technical solutions:

[0008] A DC transmission converter station wiring system for offshore wind power includes a wind farm, an AC field module connected to the wind farm, a transformer module connected to the AC field module, a converter module connected to the transformer module, and a DC field module connected to the converter module. The AC field module includes at least N sets of double-section busbars and wiring assemblies connecting adjacent, first-to-last, or adjacent sets of double-section busbars. The transformer module includes a transformer connected to each set of double-section busbars. The wind farm is equipped with an incoming line group connected to each set of double-section busbars. The transformer includes two sets of grid-side windings and one set of valve-side windings. The incoming line group includes two incoming line subgroups. Each set of double-section busbars includes two busbars.

[0009] Each of the busbars is connected to the corresponding incoming line group of the incoming line group and the two sets of grid-side windings of the transformer, and the valve-side winding of the transformer is connected to the corresponding converter module; where N is a natural number greater than 1.

[0010] Preferably, if the two sets of double-section busbars connected by the wiring assembly are a first double-section busbar and a second double-section busbar, the wiring assembly includes a first wiring element and a second wiring element. The first end of the first wiring element is connected to the first busbar of the first double-section busbar, and the second end of the first wiring element is connected to the first busbar of the second double-section busbar. The first end of the second wiring element is connected to the second busbar of the first double-section busbar, and the second end of the second wiring element is connected to the second busbar of the second double-section busbar. The wiring element is a circuit breaker or a disconnecting switch.

[0011] Preferably, a first switching element is provided between the incoming line group of the incoming line group and the corresponding busbar connection, a second switching element is also provided between each busbar and the grid-side winding of the corresponding transformer, and a third switching element is also provided between the valve-side winding of the transformer and the converter module connection.

[0012] Preferably, the transformer is a three-phase transformer.

[0013] Preferably, when the offshore wind power DC transmission converter station wiring system is operating normally, the rated power of each incoming line group is distributed equally according to the total rated power of the wind farm.

[0014] The present invention also provides a control method for the wiring system of an offshore wind power DC transmission converter station, comprising the following steps:

[0015] Obtain the rated transmission power of the offshore wind power DC system, the rated AC voltage of the wind farm, and the maximum current that the AC field modules are allowed to carry;

[0016] Based on the rated transmission power, the rated AC voltage, and the maximum current, the total rated current and the number of transformers on the AC side of the AC field module are calculated.

[0017] The number of dual-section busbars and the number of incoming line groups of the offshore wind power DC system are determined based on the number of transformers; and the wiring is carried out according to the offshore wind power DC transmission converter station wiring system described above, based on the number of transformers, the number of dual-section busbars and the number of incoming line groups.

[0018] Obtain the operating status of the AC field module in the wiring system of the offshore wind power DC transmission converter station;

[0019] According to the operating status, control the closing or opening of the wiring elements of the AC field module and the switching elements connected to the AC field module in the offshore wind power DC transmission converter station wiring system, and control the current transmitted by each incoming line group so as to enable the offshore wind power DC transmission converter station wiring system to transmit power normally.

[0020] The number of transformers, the number of double-section busbars, and the number of incoming line groups are all the same and denoted as N, where N is a natural number greater than 1.

[0021] Preferably, the double-section busbar includes a first busbar and a second busbar, and the incoming line group includes a first incoming line subgroup and a second incoming line subgroup. The total rated current is denoted as I. ac If the operating state is that the AC field module is in normal working state, then the switching elements connecting the first busbar of each group of double-section busbars to the first incoming subgroup of the corresponding incoming line group and a set of grid-side windings of the corresponding transformer are closed; the switching elements connecting the second busbar of each group of double-section busbars to the second incoming subgroup of the corresponding incoming line group and another set of grid-side windings of the corresponding transformer are closed; the wiring elements in the wiring assembly are disconnected to disconnect all the busbars; and the transmission current of each incoming subgroup of each group of the incoming line group is controlled not to exceed I. ac / 2N.

[0022] Preferably, the total rated current is denoted as I. ac The double-section busbar includes a first busbar and a second busbar, and the incoming line group includes a first incoming line group and a second incoming line group. If the operating state is that one busbar in any group of double-section busbars in the AC field module is faulty or under maintenance, and the busbar of the double-section busbar that is faulty or under maintenance is denoted as the second busbar, then the switching elements controlling the first busbar of the double-section busbar to be connected to the corresponding first incoming line group, the second incoming line group and the two groups of grid-side windings of the transformer are closed, and the second busbar of the double-section busbar is disconnected from the switching elements connecting the corresponding first incoming line group, the second incoming line group and the two groups of grid-side windings of the transformer.

[0023] The switching elements that control the normal operation of other groups of double-section busbars are connected to the first incoming group of the corresponding incoming group and a group of grid-side windings of the corresponding transformer, respectively. The switching elements that control the normal operation of other groups of double-section busbars are connected to the second incoming group of the corresponding incoming group and another group of grid-side windings of the corresponding transformer, respectively.

[0024] The wiring elements in the control wiring assembly are disconnected to disconnect all the busbars, and the transmission current of each group of incoming lines in each group of incoming lines is controlled to be no greater than I. ac / 2N.

[0025] Preferably, when N is greater than 2, the total rated current is denoted as I. ac The maximum current is denoted as I. capN transformers are denoted as the first transformer, the nth transformer, and the Nth transformer, respectively. The double-section busbar includes the first busbar and the second busbar. The incoming line group includes the first incoming line group and the second incoming line group. The double-section busbar and the incoming line group corresponding to the first transformer are denoted as the first double-section busbar and the first incoming line group, respectively. The double-section busbar and the incoming line group corresponding to the nth transformer are denoted as the nth double-section busbar and the nth incoming line group, respectively. The double-section busbar and the incoming line group corresponding to the Nth transformer are denoted as the Nth double-section busbar and the Nth incoming line group, where n∈N. The double-section busbar adjacent to the first double-section busbar is denoted as the second double-section busbar.

[0026] The operating state is when any transformer fails or is under maintenance, the switching element connecting the first incoming group of each incoming line group to the first busbar of the corresponding double-section busbar is closed, and the switching element connecting the second incoming group of each incoming line group to the second busbar of the corresponding double-section busbar is closed; the switching element connecting one set of grid-side windings of other normal transformers to the first busbar of the corresponding double-section busbar is closed, and the switching element connecting the other set of grid-side windings of other normal transformers to the second busbar of the corresponding double-section busbar is closed.

[0027] If the operating state is that the first transformer has failed or is under maintenance, the connection element connecting the first busbar of the first double-section busbar to the first busbar of the second double-section busbar, and the connection element connecting the second busbar of the first double-section busbar to the second busbar of the Nth double-section busbar, are also controlled to close, and the transmission current of the second incoming subgroup of the second incoming line group and the first incoming subgroup of the Nth incoming line group is controlled to be no greater than I. cap The transmission current of the first incoming group of the second incoming line group and the second incoming group of the Nth incoming line group is controlled to be no greater than (I ac / 3-I cap The current supplied to the two groups of incoming lines in the first incoming line group is controlled to be no greater than the current threshold, and the current supplied to each group of incoming lines in the incoming line groups other than the first, second, and Nth incoming line groups is no greater than I. ac / 2N; or control the closing of the connection element connecting the second busbar of the first double-section busbar to the second busbar of the second double-section busbar and the closing of the connection element connecting the first busbar of the first double-section busbar to the first busbar of the Nth double-section busbar; control the transmission current of the first incoming group of the second incoming group and the second incoming group of the Nth incoming group to be no greater than I cap The transmission current of the second incoming line subgroup of the second incoming line group and the first incoming line subgroup of the Nth incoming line group is controlled to be no greater than (I ac / 3-I capThe current supplied to the two subgroups of the first incoming line group is controlled to be no greater than the current threshold; the current supplied to each subgroup of the incoming line groups other than the first, second, and Nth incoming line groups is controlled to be no greater than I. ac / 2N;

[0028] If the operating state is that the nth transformer has failed or is under maintenance, the connection element connecting the first busbar of the nth double-section busbar to the first busbar of the (n-1)th double-section busbar, and the connection element connecting the second busbar of the nth double-section busbar to the second busbar of the (n+1)th double-section busbar, are also controlled to close; the transmission current of the second incoming subgroup of the (n-1)th incoming line group and the first incoming subgroup of the (n+1)th incoming line group is controlled to be no greater than I. cap The transmission current of the first incoming subgroup of the (n-1)th incoming line group and the second incoming subgroup of the (n+1)th incoming line group is controlled to be no greater than (I ac / 3-I cap The current supplied by the two groups of incoming lines in the nth incoming line group is controlled to be no greater than the current threshold, and the current supplied by each group of incoming lines in the incoming line groups other than the (n-1)th, nth, and (n+1)th incoming line groups is no greater than I. ac / 2N; or control the closing of the wiring element connecting the second busbar of the nth double-section busbar to the second busbar of the (n-1)th double-section busbar and the closing of the wiring element connecting the first busbar of the nth double-section busbar to the first busbar of the (n+1)th double-section busbar; control the transmission current of the first incoming group of the (n-1)th incoming group and the second incoming group of the (n+1)th incoming group to be no greater than I cap The transmission current of the second incoming group of the (n-1)th incoming line group and the first incoming group of the (n+1)th incoming line group is controlled to be no greater than (I ac / 3-I cap The current supplied by the two groups of incoming lines in the nth incoming line group is controlled to be no greater than the current threshold, and the current supplied by each group of incoming lines in the incoming line groups other than the (n-1)th, nth, and (n+1)th incoming line groups is no greater than I. ac / 2N;

[0029] If the operating state is that the Nth transformer has failed or is under maintenance, the connection element connecting the second busbar of the first double-section busbar to the second busbar of the Nth double-section busbar and the connection element connecting the first busbar of the (N-1)th double-section busbar to the first busbar of the Nth double-section busbar are also controlled to close; the transmission current of the first incoming line group of the first incoming line group and the second incoming line group of the (N-1)th incoming line group is controlled to be no greater than I. capThe transmission current of the second incoming group of the first incoming line group and the first incoming group of the (N-1)th incoming line group is controlled to be no greater than (I ac / 3-I cap The current supplied to the two groups of incoming lines in the Nth incoming line group is controlled to be no greater than the current threshold, and the current supplied to each group of incoming lines in the incoming line groups other than the first incoming line group, the (N-1)th incoming line group, and the Nth incoming line group is no greater than I. ac / 2N; or control the connection element connecting the first busbar of the first double-section busbar to the first busbar of the Nth double-section busbar to close, and control the connection element connecting the second busbar of the N-1th double-section busbar to the second busbar of the Nth double-section busbar to close; control the transmission current of the second incoming group of the first incoming group and the first incoming group of the N-1th incoming group to be no greater than I cap The transmission current of the first incoming line subgroup of the first incoming line group and the second incoming line subgroup of the (N-1)th incoming line group is controlled to be no greater than (I ac / 3-I cap The current supplied by the two subgroups of the Nth incoming line group is controlled to be no greater than the current threshold, and the current supplied by each subgroup of the incoming line group other than the first incoming line group, the (N-1)th incoming line group, and the Nth incoming line group is no greater than I. ac / 2N;

[0030] Wherein, the current threshold is 2I cap Subtract the total current of the incoming line group corresponding to the dual-section busbar that receives the transferred power.

[0031] The present invention also provides a terminal device, including a processor and a memory;

[0032] The memory is used to store program code and transmit the program code to the processor;

[0033] The processor is used to execute the control method of the offshore wind power DC transmission converter station wiring system described above according to the instructions in the program code.

[0034] As can be seen from the above technical solutions, the embodiments of the present invention have the following advantages:

[0035] This offshore wind power DC transmission converter station wiring system, control method, and equipment, through the wiring of AC field modules and transformer modules, can continue to transmit the corresponding wind farm incoming power when a bus of the AC field module or the transformer of the transformer module fails. It can also reduce the current carrying requirements of the equipment, reduce the difficulty of equipment manufacturing, and solve the problem of high AC side current of the converter station when there is no step-up station. It realizes offshore wind power DC transmission without step-up station, without the need to add additional step-up station and converter station, reducing construction costs and operation and maintenance costs. It solves the technical problem that existing offshore converter stations using DC transmission methods require the construction of multiple step-up stations and converter stations, which are costly and difficult to operate and maintain. By employing a transformer with two sets of grid-side windings and two sets of incoming line groups of the wind farm being equally connected to two busbars of N sets of double-section busbars, and by simultaneously using multiple busbars of N sets of double-section busbars for current carrying during offshore wind power DC transmission, the current carrying requirements of equipment such as transformer modules and AC field modules can be reduced by half, solving the problem of difficult selection of AC equipment. This makes the control method of the offshore wind power DC transmission converter station wiring system applicable to the electrical wiring of offshore wind power DC transmission converter stations that do not require offshore substations, and the control method of the offshore wind power DC transmission converter station wiring system is also applicable to the AC side wiring of offshore substations with larger capacity. Attached Figure Description

[0036] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0037] Figure 1 This is an electrical schematic diagram of three sets of double-section busbars in the offshore wind power DC transmission converter station wiring system according to an embodiment of the present invention.

[0038] Figure 2 This is an electrical schematic diagram of two sets of double-section busbars in the offshore wind power DC transmission converter station wiring system described in an embodiment of the present invention.

[0039] Figure 3 This is a flowchart illustrating the steps of the control method for the offshore wind power DC transmission converter station wiring system according to an embodiment of the present invention.

[0040] Figure 4 This is a wiring diagram for a control method with a quantity N of 3 for the offshore wind power DC transmission converter station wiring system described in an embodiment of the present invention.

[0041] Figure 5 This is a wiring diagram for a control method with a quantity N of 2 for the offshore wind power DC transmission converter station wiring system described in an embodiment of the present invention.

[0042] Figure 6 Wiring diagram for existing offshore wind power DC transmission. Detailed Implementation

[0043] To make the objectives, features, and advantages of this invention more apparent and understandable, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described below are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0044] This application provides a wiring system, control method, and equipment for an offshore wind power DC transmission converter station, which solves the technical problem that existing offshore converter station wiring uses DC transmission, requiring the construction of multiple step-up substations and converter stations, resulting in high costs and high maintenance difficulties.

[0045] Example 1:

[0046] Figure 1 This is an electrical schematic diagram of three sets of double-section busbars in the offshore wind power DC transmission converter station wiring system according to an embodiment of the present invention. Figure 2 This is an electrical schematic diagram of two sets of double-section busbars in the offshore wind power DC transmission converter station wiring system described in an embodiment of the present invention.

[0047] like Figure 1 As shown, this embodiment of the invention provides a wiring system for an offshore wind power DC transmission converter station, including a wind farm 10, an AC field module 20 connected to the wind farm 10, a transformer module 30 connected to the AC field module 20, a converter module 40 connected to the transformer module 30, and a DC field module 50 connected to the converter module 40. The AC field module 20 includes at least N sets of double-section busbars and wiring assemblies connecting adjacent, first and last, or adjacent sets of double-section busbars. The transformer module 30 includes a transformer connected to each set of double-section busbars. The wind farm is provided with an incoming line group connected to each set of double-section busbars. The transformer includes two sets of grid-side windings and one set of valve-side windings. The incoming line group includes two incoming line subgroups. Each set of double-section busbars includes two busbars. Each busbar is connected to the incoming line subgroup of the corresponding incoming line group and the two sets of grid-side windings of the transformer. The valve-side winding of the transformer is connected to the corresponding converter module. Wherein, N is a natural number greater than 1.

[0048] It should be noted that when N is 2, two adjacent sets of double-segment busbars are connected by a wiring assembly. When N is greater than 2, adjacent, first and last sets of double-segment busbars are connected by a wiring assembly to form a ring connection.

[0049] like Figure 2As shown in the embodiment of the present invention, N is 2. Therefore, the offshore wind power DC transmission converter station wiring system is equipped with two sets of double-section busbars, two sets of incoming line groups, and two transformers. The two sets of incoming line groups include four incoming line subgroups, namely the first incoming line subgroup 11-1, the second incoming line subgroup 11-2, the third incoming line subgroup 11-3, and the fourth incoming line subgroup 11-4. The two sets of double-section busbars 21 are the first double-section busbar 21-1 and the second double-section busbar 21-2, respectively. The two transformers are the first transformer 31-1 and the second transformer 31-2, respectively. The first incoming line subgroup 11-1 and the second incoming line subgroup 11-2 are respectively connected to the two busbars of the first double-section busbar 21-1 through a first switching element. The two busbars of segment bus 21-1 are also connected to the two sets of grid-side windings of the first transformer 31-1 through the second switching element. The valve-side winding of the first transformer 31-1 is connected to the converter module 40 through the third switching element. The third incoming line group 11-3 and the fourth incoming line group 11-4 are respectively connected to the two busbars of the second double segment bus 21-2 through the first switching element. The two busbars of the second double segment bus 21-2 are also connected to the two sets of grid-side windings of the second transformer 31-2 through the second switching element. The valve-side winding of the second transformer 31-2 is connected to the converter module 40 through the third switching element. The first double segment bus 21-1 and the second double segment bus 21-2 are connected by a wiring assembly 22. Alternatively, a first switching element may be provided between the two groups of incoming lines of each group of incoming lines and the two busbars of each group of double-section busbars, a second switching element may be provided between the two busbars of each group of double-section busbars and the grid-side winding of each transformer, and a third switching element may be provided between the valve-side winding of each transformer and the converter module 40.

[0050] like Figure 1As shown in the embodiment of the present invention, N is 3. Therefore, the offshore wind power DC transmission converter station wiring system is equipped with three sets of double-section busbars, three sets of incoming line groups, and three transformers. The three sets of incoming line groups include six incoming line subgroups, namely the first incoming line subgroup 11-1, the second incoming line subgroup 11-2, the third incoming line subgroup 11-3, the fourth incoming line subgroup 11-4, the fifth incoming line subgroup 11-5, and the sixth incoming line subgroup 11-6. The three sets of double-section busbars 21 are respectively the first double-section busbar 21-1, the second double-section busbar 21-2, and the sixth double-section busbar 21-6. The three double-section busbar 21-3 has three transformers: the first transformer 31-1, the second transformer 31-2, and the third transformer 31-3. The first incoming line group 11-1 and the second incoming line group 11-2 are respectively connected to the two busbars of the first double-section busbar 21-1 via a first switching element. The two busbars of the first double-section busbar 21-1 are also connected to the two sets of grid-side windings of the first transformer 31-1 via a second switching element. The valve-side winding of the first transformer 31-1 is connected to the converter module 40 via a third switching element. Incoming line group 11-3 and the fourth incoming line group 11-4 are respectively connected to the two busbars of the second double-section bus 21-2 via the first switching element. The two busbars of the second double-section bus 21-2 are also connected to the two sets of grid-side windings of the second transformer 31-2 via the second switching element. The valve-side winding of the second transformer 31-2 is connected to the converter module 40 via the third switching element. The fifth incoming line group 11-5 and the sixth incoming line group 11-6 are respectively connected to the two busbars of the third double-section bus 21-3 via the first switching element. The two busbars of busbar 21-3 are also connected to the two sets of grid-side windings of the third transformer 31-3 via a second switching element. The valve-side winding of the third transformer 31-3 is connected to the converter module 40 via a third switching element. The first double-section busbar 21-1 and the second double-section busbar 21-2 are connected via a wiring assembly 22, as are the second double-section busbar 21-2 and the third double-section busbar 21-3. Alternatively, a first switching element can be installed between the two sets of incoming sub-sections of each incoming main group and the two busbars of each double-section busbar, a second switching element can be installed between the two busbars of each double-section busbar and the grid-side windings of each transformer, and a third switching element can be installed between the valve-side windings of each transformer and the converter module 40.

[0051] It should be noted that the switching element can be a circuit breaker or a disconnecting switch. The wiring system of this offshore wind power DC transmission converter station is configured with a matching number of incoming line groups, transformers, and double-section busbars. The connection between each incoming line group and any one of the double-section busbars is switched by the switching state of the first switching element between the incoming line groups and the double-section busbars. Similarly, the connection between the transformer and any one of the double-section busbars is achieved by switching the switching state of the second switching element between the transformer's grid-side winding and the double-section busbars. In this embodiment, the AC field module can be a GIS device.

[0052] In an embodiment of the present invention, the wind farm 10 is mainly used to provide input power. If the offshore wind power DC transmission converter station wiring system is operating normally, the rated power of each incoming line group in the wind farm 10 is distributed equally according to the total rated power of the incoming line groups of the wind farm 10.

[0053] It should be noted that the total power of the N incoming line groups is equal. Since the voltage of each incoming line group is equal, the total current of each incoming line group is essentially equal.

[0054] In an embodiment of the present invention, each transformer includes two sets of grid-side windings and one set of valve-side windings, such that the transformer is connected to a double-section busbar by means of split grid-side windings.

[0055] It should be noted that a three-phase transformer is preferred. In this embodiment, the transformer is equipped with two sets of grid-side windings and one set of valve-side windings, so that the transformer module 30 adopts a split-winding transformer, which can reduce the current carrying requirements of the AC field module 20 and the transformer module 30.

[0056] In an embodiment of the present invention, the converter module 40 is mainly composed of several flexible DC power modules.

[0057] In an embodiment of the present invention, the wiring assembly 22 is mainly used to connect two adjacent, first and last, or two adjacent double-section busbars. The two double-section busbars connected by the wiring assembly are the first double-section busbar and the second double-section busbar. The wiring assembly 22 includes a first wiring element and a second wiring element. The first end of the first wiring element is connected to the first busbar of the first double-section busbar, and the second end of the first wiring element is connected to the first busbar of the second double-section busbar. The first end of the second wiring element is connected to the second busbar of the first double-section busbar, and the second end of the second wiring element is connected to the second busbar of the second double-section busbar.

[0058] It should be noted that the wiring assembly 22 can be a circuit breaker, a disconnecting switch, or an electronic device formed by combining a disconnecting switch and a circuit breaker.

[0059] In an embodiment of the present invention, each set of dual-section busbars is provided with two busbars, so that the AC field module 20 uses two busbars. If a certain busbar or transformer fails, different busbars in the AC field module 20 can be used without affecting the full-power transmission of offshore wind power.

[0060] In an embodiment of the present invention, the offshore wind power DC transmission converter station wiring system adopts a double-busbar, double-segmented busbar configuration via AC field module 20. Each full-power transformer uses a split winding on the grid side. The incoming line group of wind farm 10 is divided into N parts according to power, and each part is connected to one of the N incoming line groups. During normal operation, there is a double-segmented busbar consisting of two busbars, each connected to an incoming line group with a split transformer grid-side winding. When one of the double-segmented busbars fails or is under maintenance, the other busbars in the N double-segmented busbar groups are operational. When one transformer fails, half of the incoming line groups of wind farm 10 are connected to one of the double-segmented busbars, the wiring assembly of that busbar is closed, and the power is connected to the working transformer via the other busbar of the other double-segmented busbar group. At this time, the power of each connection line in AC field module 20 and transformer 30 is half of the rated input power of wind farm 10.

[0061] This invention provides a wiring system for an offshore wind power DC transmission converter station. Through the wiring of the AC field module and the transformer module, it can continue to transmit the incoming power of the corresponding wind farm when a bus of the AC field module or the transformer of the transformer module fails. It can also reduce the current carrying requirements of the equipment, reduce the difficulty of equipment manufacturing, and realize offshore wind power DC transmission without a step-up station. It eliminates the need for additional step-up stations and converter stations, reduces construction costs and operation and maintenance costs, and solves the technical problem that existing offshore converter station wiring uses DC transmission, which requires the construction of multiple step-up stations and converter stations, resulting in high costs and high operation and maintenance difficulties.

[0062] Example 2:

[0063] Figure 3 This is a flowchart illustrating the steps of the control method for the offshore wind power DC transmission converter station wiring system according to an embodiment of the present invention. Figure 4 This is a wiring diagram for a control method with a quantity N of 3 for the offshore wind power DC transmission converter station wiring system described in this embodiment of the invention. Figure 5 This is a wiring diagram for a control method with a quantity N of 2 for the offshore wind power DC transmission converter station wiring system described in an embodiment of the present invention.

[0064] like Figure 3 As shown in the figure, this embodiment of the invention also provides a control method for the wiring system of an offshore wind power DC transmission converter station, including the following steps:

[0065] S10. Obtain the rated transmission power of the offshore wind power DC system, the rated AC voltage of the wind farm, and the maximum current that the AC field module is allowed to carry.

[0066] It should be noted that in step S10, the rated transmission power required by the offshore wind power DC system, the rated AC voltage of the wind farm, and the maximum current that the AC field module can carry can be obtained, providing basic data for determining the number of transformers required in the future.

[0067] S20. Based on the rated transmission power, AC rated voltage, and maximum current, calculate the total rated current and the number of transformers on the AC side of the AC field module.

[0068] It should be noted that in step S20, the number of transformers and the total rated current that the AC field modules in the aforementioned offshore wind power DC transmission converter station wiring system can withstand are calculated based on the rated transmission power, AC rated voltage, and maximum current. In this embodiment, the total rated current is calculated based on the rated transmission power and AC rated voltage using a first calculation formula, and the number of transformers is calculated based on the total rated current and maximum current using a second calculation formula. The first calculation formula is as follows:

[0069]

[0070] The second calculation formula is:

[0071]

[0072] In the formula, P is the rated transmission power, and U ac For AC rated voltage, I ac I is the total rated current on the AC side of the AC field module. cap N represents the maximum current that the AC field module is allowed to carry, and N is the number of transformers.

[0073] S30. Determine the number of double-section busbars and the number of incoming line groups for the offshore wind power DC system based on the number of transformers; and connect the offshore wind power DC transmission converter station according to the above-mentioned wiring system based on the number of transformers, the number of double-section busbars and the number of incoming line groups.

[0074] It should be noted that, as shown in the offshore wind power DC transmission converter station wiring system of Example 1, the number of transformers matches the number of incoming main units and double-section busbars. Therefore, in step S30, the number of double-section busbars and incoming main units of the offshore wind power DC system can be determined based on the number of transformers. The offshore wind power DC transmission converter station wiring system of Example 1 is then installed and wired according to the determined number of transformers, incoming main units, and double-section busbars. In this embodiment, the number of transformers, double-section busbars, and incoming main units are all the same and denoted as N, where N is a natural number greater than 1. The content of the offshore wind power DC transmission converter station wiring system in Example 2 has already been described in detail in Example 1, and will not be described in detail again in Example 2.

[0075] S40. Obtain the operating status of the AC field module in the wiring system of the offshore wind power DC transmission converter station.

[0076] It should be noted that step S40 mainly involves obtaining the operating status of the AC field module in the offshore wind power DC transmission converter station wiring system connected according to step S30, so as to provide basic judgment data for subsequent steps.

[0077] S50. Based on the operating status, control the closing or opening of the wiring elements of the AC field module and the switching elements connected to the AC field module in the offshore wind power DC transmission converter station wiring system, and control the current transmitted by each incoming line group, so as to ensure normal power transmission of the offshore wind power DC transmission converter station wiring system.

[0078] It should be noted that in step S50, the connection elements, the first switch element and the second switch element of the offshore wind power DC transmission converter station connection system can be controlled to close or open according to the operating status of the AC side module, and the transmission current of each group of incoming line groups can be controlled to ensure the normal power transmission of the offshore wind power DC transmission converter station connection system.

[0079] like Figures 1 to 5 As shown, in this embodiment of the invention, the dual-section busbar includes a first busbar and a second busbar, the incoming line group includes a first incoming line subgroup and a second incoming line subgroup, and the total rated current is denoted as I. ac If the AC field module is in normal operating condition, the switching elements controlling the first busbar of each double-section busbar group to connect to the first incoming subgroup of the corresponding incoming line group and one set of grid-side windings of the corresponding transformer are closed; the switching elements controlling the second busbar of each double-section busbar group to connect to the second incoming subgroup of the corresponding incoming line group and another set of grid-side windings of the corresponding transformer are closed; and the wiring elements in the wiring assembly are disconnected to disconnect all busbars; and the transmission current of each incoming subgroup of each incoming line group is controlled not to exceed I. ac / 2N.

[0080] It should be noted that during normal operation of the offshore wind power DC transmission converter station wiring system, the rated power of each incoming line group of the wind farm is evenly distributed according to the total rated power of the entire wind farm. Therefore, the current of each incoming line group of the wind farm and the incoming line group current of each grid-side winding of each transformer do not exceed I. ac / 2N will not exceed I. cap .

[0081] like Figure 2 and Figure 5 As shown, in one embodiment of the present invention, if N is 2 and the AC field module is in normal operating condition with both buses, the switching elements controlling the first incoming line group and one set of grid-side windings of the first transformer to be connected to one bus of the first double-section bus are closed; the switching elements controlling the second incoming line group and the other set of grid-side windings of the first transformer to be connected to the other bus of the first double-section bus are closed; the switching elements controlling the third incoming line group and one set of grid-side windings of the second transformer to be connected to one bus of the second double-section bus are closed; the switching elements controlling the fourth incoming line group and the other set of grid-side windings of the second transformer to be connected to the other bus of the second double-section bus are closed; the first switching element controlling each other incoming line group to be connected to each bus, the second switching element controlling each bus to be connected to the transformer grid-side winding in the offshore wind power DC transmission converter station wiring system is disconnected, and the wiring element controlling the first double-section bus to be connected to the second double-section bus is disconnected.

[0082] It should be noted that if N is 2 and the AC field module is operating with both buses in normal working condition, the switching elements connecting the wind farm incoming line group 11-1 and the transformer 31-1 winding incoming line group to the first busbar of the first double-section busbar are closed; the switching elements connecting the wind farm incoming line group 11-2 and the transformer 31-1 winding incoming line group to the second busbar of the first double-section busbar are closed; the switching elements connecting the wind farm incoming line group 11-3 and the transformer 31-2 winding incoming line group to the first busbar of the second double-section busbar are closed; and the switching elements connecting the wind farm incoming line group 11-4 and the transformer 31-2 winding incoming line group to the second busbar of the second double-section busbar are closed. The rated power of each incoming line group in each wind farm is evenly distributed according to the total rated power of the entire wind farm. Therefore, the current of each incoming line group in each wind farm and the current of each transformer winding incoming line group do not exceed I. ac / 4, and will not exceed I. cap .

[0083] In one embodiment of the present invention, the total rated current is denoted as I. acThe double-section busbar includes a first busbar and a second busbar. The incoming line group includes a first incoming line group and a second incoming line group. If the operating status is such that one busbar in any group of double-section busbars in the AC field module is faulty or under maintenance, and the busbar of the double-section busbar with a faulty or under maintenance is denoted as the second busbar, then the switching elements controlling the first busbar of this double-section busbar to connect with the corresponding first incoming line group, second incoming line group, and the two sets of grid-side windings of the transformer are closed. The second busbar of this double-section busbar is connected with the corresponding first incoming line group, second incoming line group, and the two sets of grid-side windings of the transformer. The switching elements connecting the two sets of grid-side windings of the group and the transformer are disconnected; the switching elements controlling the normal operation of the other groups' double-section busbars are closed, connecting the first busbar of the corresponding incoming main group and the first set of grid-side windings of the corresponding transformer respectively; the switching elements controlling the normal operation of the other groups' double-section busbars are closed, connecting the second busbar of the corresponding incoming main group and the other set of grid-side windings of the corresponding transformer respectively; the wiring elements in the control wiring assembly are disconnected to disconnect all busbars, and the transmission current of each incoming main group's each incoming subgroup is controlled to be no greater than I. ac / 2N.

[0084] like Figure 2 and Figure 5As shown, it should be noted that if N is 2 and the first busbar of the first double-section busbar experiences a fault or maintenance, the switching elements controlling the two sets of grid-side windings of the first incoming line group 11-1, the second incoming line group 11-2, and the first transformer 31-1 to connect to the second busbar of the first double-section busbar will close; the switching elements controlling the one set of grid-side windings of the third incoming line group 11-3 and the second transformer 31-2 to connect to the first busbar of the second double-section busbar will close; the switching elements controlling the other set of grid-side windings of the fourth incoming line group 11-4 and the second transformer 31-2 to connect to the second busbar of the second double-section busbar will close; the first switching element connecting each other incoming line group to each busbar, the second switching element connecting each busbar to the transformer grid-side winding in the offshore wind power DC transmission converter station wiring system will disconnect, and the first double-section busbar and the second double-section busbar will disconnect. The line is disconnected; or if N is 2 and the first busbar of the second double-section busbar is under maintenance, the switching elements controlling the two sets of grid-side windings of the third incoming line group 11-3, the fourth incoming line group 11-4, and the second transformer 31-2 to be connected to the second busbar of the second double-section busbar are closed; one set of grid-side windings of the first incoming line group 11-1 and the first transformer 31-1 to be connected to the first busbar of the first double-section busbar are closed, and the other set of grid-side windings of the second incoming line group 11-2 and the first transformer 31-1 to be connected to the second busbar of the first double-section busbar are closed; the first switching elements of each other incoming line group connected to each busbar, the second switching elements of each busbar connected to the transformer grid-side windings in the offshore wind power DC transmission converter station wiring system are disconnected, and the first double-section busbar and the second double-section busbar are disconnected. In this embodiment, if one busbar of a set of double-section busbars in the offshore wind power DC transmission converter station wiring system is unavailable, the wind farm incoming line group and the transformer grid-side winding incoming line group originally connected to the busbar of the set of double-section busbars can be reconnected to the other busbar of the set of double-section busbars. At this time, the incoming line current of each wind farm group and the grid-side winding incoming line current of each transformer group can still not exceed I. ac / 4, and will not exceed I. cap .

[0085] like Figure 2 and Figure 5As shown, in an embodiment of the present invention, if N is 2 and the first transformer 31-1 is in a fault or maintenance state, the switching elements controlling the first incoming line group 11-1 and the second incoming line group 11-2 to connect to the first busbar of the first double-section busbar are closed; the switching elements controlling the third incoming line group 11-3, the fourth incoming line group 11-4 and one set of grid-side windings of the second transformer 31-2 to connect to the second busbar of the second double-section busbar are closed; the switching element controlling the other set of grid-side windings of the second transformer 31-2 to connect to the first busbar of the second double-section busbar is closed; the wiring element controlling the connection between the first busbar of the first double-section busbar and the first busbar of the second double-section busbar is closed; and the first switching element controlling the connection between each other incoming line group and each busbar in the offshore wind power DC transmission converter station wiring system, the second switching element controlling the connection between each busbar and the transformer grid-side winding, and the wiring element controlling the connection between the second busbar of the first double-section busbar and the second busbar of the second double-section busbar are disconnected.

[0086] It should be noted that if one transformer in the offshore wind power DC transmission converter station wiring system is unavailable, taking the first transformer 31-1 as an example, the first switching element connecting the first incoming line group 11-1 and the second incoming line group 11-2 of the wind farm to the first busbar of the first double-section busbar will be closed, and the wiring element between the first busbar of the first double-section busbar and the first busbar of the second double-section busbar will be closed, thereby transferring the current of the first incoming line group 11-1 and the second incoming line group 11-2 of the wind farm to the second busbar of the second double-section busbar; and the third incoming line group 11-3 and the fourth incoming line group 11-4 of the wind farm will be connected to the second double-section busbar. When the first switching element connected to the second busbar closes, the switching element connecting one set of grid-side windings of the second transformer 31-2 to the first busbar of the second double-section busbar closes, and the switching element connecting the other set of grid-side windings of the second transformer 31-2 to the second busbar of the second double-section busbar closes. This allows the total current of the first incoming line group 11-1 and the second incoming line group 11-2 of the wind farm to be sent out through one set of grid-side windings of the second transformer 31-2. The total current of the third incoming line group 11-3 and the fourth incoming line group 11-4 of the wind farm will be sent out through the other set of grid-side windings of the second transformer 31-2. At this time, the total current of the two parts may exceed the maximum current I. cap It is necessary to coordinate with the control that the current delivered by each group of grid-side windings of the second transformer 31-2 does not exceed I. cap .

[0087] In this embodiment of the invention, the control method for the offshore wind power DC transmission converter station wiring system uses DC transmission power frequency P dcTaking a 600MW wind farm as an example, the high-voltage output voltage of each incoming line group in the current wind farm can reach 66kV. If directly connected to the offshore converter station, the total AC current is 5.26kA, which cannot be met by a single 66kV transformer winding and switchgear. By adopting the grid-side split-winding transformer of the offshore wind power DC transmission converter station connection system, the current of each grid-side winding of the transformer is reduced to 2.63kA. That is, the current flowing through the double-section busbar connecting the transformer and the AC field module 20 is reduced to 2.63kA, which allows the current of the transformer and AC equipment to meet the current requirements. When the two busbars of the double-section busbar are in normal operating condition, each of the two transformers carries half of the rated DC power, and each grid-side winding carries 1 / 4 of the rated DC power. That is, the current of each connection line between each grid-side winding and the input transformer is 1.31kA. The four grid-side windings of the two transformers are connected to the four busbars of the two double-section busbars respectively. The rated transmission power of wind farm 10 is evenly distributed across the four incoming line groups, so the current of each incoming line group of wind farm 10 is also 1.31kA. When one busbar of the double-section busbar is under maintenance or one transformer is faulty, the following situations exist: First, when one transformer fails, the power of the wind farm incoming line group connected to that transformer on the corresponding double-section busbar can be transferred to the other double-section busbar via closed-loop connection elements, without affecting the overall power transmission of offshore wind power. In this case, the operating current of each busbar of the AC wind farm module 20 is 2.63kA. Second, when one busbar of the double-section busbar fails, the two grid-side windings of the corresponding transformer can be simultaneously connected to the other busbar of that double-section busbar, and the transmission power of the wind farm incoming line group is also simultaneously transferred to the other busbar of that double-section busbar, without affecting the overall power transmission of offshore wind power. In this case, the operating current of the other busbar of that double-section busbar is 2.63kA. Third, when the wiring assembly 22 fails, if no other failures occur simultaneously, the four buses of the two sets of double-section busbars can operate separately, or the two buses of each set of double-section busbars can be combined into one busbar for operation, without affecting the DC power transmission of offshore wind power. In this embodiment, the current limit values ​​of each incoming group of the offshore wind power DC transmission converter station wiring system are shown in Table 1 below.

[0088] Table 1 shows the current of each incoming line group in a wind farm with N=2.

[0089]

[0090] In one embodiment of the present invention, the total rated current is denoted as I. ac The maximum current is denoted as I. capLet N transformers be denoted as Transformer 1, Transformer n, and Transformer N, respectively. A double-section busbar includes the first busbar and the second busbar. A large incoming line group includes the first incoming line group and the second incoming line group. The double-section busbar and the large incoming line group corresponding to Transformer 1 are denoted as the first double-section busbar and the first incoming line group, respectively; the double-section busbar and the large incoming line group corresponding to Transformer n are denoted as the nth double-section busbar and the nth incoming line group, respectively; and the double-section busbar and the large incoming line group corresponding to Transformer N are denoted as the Nth double-section busbar and the Nth incoming line group, where n∈N and N>2.

[0091] If the first transformer is faulty or under maintenance, the following switches are activated: The first incoming group of each incoming line group is connected to the first busbar of the corresponding double-section busbar; the second incoming group of each incoming line group is connected to the second busbar of the corresponding double-section busbar; the connection elements connecting the first busbar of the first double-section busbar to the first busbar of the nth double-section busbar and the second busbar of the first double-section busbar to the second busbar of the Nth double-section busbar are closed; the switch elements connecting one set of grid-side windings of other normal transformers to the first busbar of the corresponding double-section busbar are closed; the switch elements connecting the other set of grid-side windings of other normal transformers to the second busbar of the corresponding double-section busbar are closed; and the current supplied by the second incoming group of the nth incoming line group and the first incoming group of the Nth incoming line group is not greater than I. cap The transmission current of the first incoming line subgroup of the nth incoming line group and the second incoming line subgroup of the Nth incoming line group shall not exceed (I ac / 3-I cap The current supplied to the two groups of incoming lines in the first incoming line group shall not exceed the current threshold. The current supplied to each group of incoming lines in all other incoming line groups (excluding the first, nth, and Nth incoming line groups) shall not exceed I. ac / 2N; or control the closing of the switching element connecting the first incoming group of each incoming line group to the first busbar of the corresponding double-section busbar, control the closing of the switching element connecting the second incoming group of each incoming line group to the second busbar of the corresponding double-section busbar; control the closing of the connection element connecting the second busbar of the first double-section busbar to the second busbar of the nth double-section busbar and the connection element connecting the first busbar of the first double-section busbar to the first busbar of the Nth double-section busbar; control the closing of the switching element connecting one set of grid-side windings of other normal transformers to the first busbar of the corresponding double-section busbar, control the closing of the switching element connecting another set of grid-side windings of other normal transformers to the second busbar of the corresponding double-section busbar; control the transmission current of the first incoming group of the nth incoming line group and the second incoming group of the Nth incoming line group to be no greater than I cap The transmission current of the second incoming group of the nth incoming line group and the first incoming group of the Nth incoming line group shall not exceed (I ac / 3-Icap The current supplied to the two subgroups of the first incoming line group is controlled to be no greater than the current threshold; the current supplied to each subgroup of the incoming line groups other than the first, nth, and Nth incoming line groups is no greater than I. ac / 2N;

[0092] If the nth transformer is faulty or under maintenance, the following switches are activated: The first incoming group of each incoming line group is connected to the first busbar of the corresponding double-section busbar; the second incoming group of each incoming line group is connected to the second busbar of the corresponding double-section busbar; the connection elements connecting the first busbar of the nth double-section busbar to the first busbar of the (n-1)th double-section busbar, and the connection elements connecting the second busbar of the nth double-section busbar to the second busbar of the (n+1)th double-section busbar, are closed; the switch elements connecting one set of grid-side windings of other normal transformers to the first busbar of the corresponding double-section busbar are closed; the switch elements connecting the other set of grid-side windings of other normal transformers to the second busbar of the corresponding double-section busbar are closed; the transmission current of the second incoming group of the (n-1)th incoming line group and the first incoming group of the (n+1)th incoming line group is not greater than I. cap The transmission current of the first incoming line subgroup of the (n-1)th incoming line group and the second incoming line subgroup of the (n+1)th incoming line group shall not exceed (I ac / 3-I cap The current transmitted by the two subgroups of the nth incoming line group is controlled to be no greater than the current threshold. The current transmitted by each subgroup of the incoming line group other than the (n-1), nth, and n+1th incoming line groups is no greater than I. ac / 2N; or control the closing of the switching element connecting the first incoming group of each incoming line group to the first busbar of the corresponding double-section busbar, control the closing of the switching element connecting the second incoming group of each incoming line group to the second busbar of the corresponding double-section busbar; control the closing of the connection element connecting the second busbar of the nth double-section busbar to the second busbar of the (n-1)th double-section busbar and the connection element connecting the first busbar of the nth double-section busbar to the first busbar of the (n+1)th double-section busbar; control the closing of the switching element connecting one set of grid-side windings of other normal transformers to the first busbar of the corresponding double-section busbar, control the closing of the switching element connecting another set of grid-side windings of other normal transformers to the second busbar of the corresponding double-section busbar; control the transmission current of the first incoming group of the (n-1)th incoming line group and the second incoming group of the (n+1)th incoming line group to be no greater than I cap The transmission current of the second incoming subgroup of the (n-1)th incoming line group and the first incoming subgroup of the (n+1)th incoming line group shall not exceed (I ac / 3-I capThe current transmitted by the two subgroups of the nth incoming line group is controlled to be no greater than the current threshold. The current transmitted by each subgroup of the incoming line group other than the (n-1), nth, and n+1th incoming line groups is no greater than I. ac / 2N;

[0093] If the Nth transformer is faulty or under maintenance, the following switches are activated: The first incoming group of each incoming line group is connected to the first busbar of the corresponding double-section busbar; the second incoming group of each incoming line group is connected to the second busbar of the corresponding double-section busbar; the connection element connecting the second busbar of the first double-section busbar to the second busbar of the Nth double-section busbar, and the connection element connecting the first busbar of the N-1th double-section busbar to the first busbar of the Nth double-section busbar are activated; the switch element connecting one set of grid-side windings of other normal transformers to the first busbar of the corresponding double-section busbar is activated; the switch element connecting the other set of grid-side windings of other normal transformers to the second busbar of the corresponding double-section busbar is activated; the current supplied by the first incoming group of the first incoming line group and the second incoming group of the N-1th incoming line group is not greater than I. cap The transmission current of the second incoming subgroup of the first incoming line group and the first incoming subgroup of the (N-1)th incoming line group is not greater than (I ac / 3-I cap The current supplied to the two subgroups of the Nth incoming line group is controlled to be no greater than the current threshold. The current supplied to each subgroup of the incoming line group other than the first, (N-1), and Nth incoming line groups is no greater than I. ac / 2N; or control the closing of the switching elements connecting the first incoming group of other incoming groups (excluding the first incoming group) to the first busbar of the corresponding double-section busbar; control the closing of the switching elements connecting the second incoming group of other incoming groups (excluding the first incoming group) to the second busbar of the corresponding double-section busbar; control the closing of the switching elements connecting the two incoming groups of the first incoming group to the first busbar of the first double-section busbar; control the closing of the wiring elements connecting the first busbar of the first double-section busbar to the first busbar of the Nth double-section busbar and the wiring elements connecting the second busbar of the N-1th double-section busbar to the second busbar of the Nth double-section busbar; control the closing of the switching elements connecting one set of grid-side windings of other normal transformers to the first busbar of the corresponding double-section busbar; control the closing of the switching elements connecting another set of grid-side windings of other normal transformers to the second busbar of the corresponding double-section busbar; control the transmission current of the second incoming group of the first incoming group and the first incoming group of the N-1th incoming group to be no greater than I cap The transmission current of the first incoming line subgroup of the first incoming line group and the second incoming line subgroup of the (N-1)th incoming line group shall not exceed (I ac / 3-I capThe current supplied by the two subgroups of the Nth incoming line group is controlled to be no greater than the current threshold. The current supplied by each subgroup of the incoming line group other than the first, N-1, and Nth incoming line groups is no greater than I. ac / 2N;

[0094] Wherein, the current threshold is 2I cap Subtract the total current of the incoming line group corresponding to the dual-section busbar that receives the transferred power.

[0095] like Figure 1 and Figure 4 As shown in the embodiment of the present invention, N is 3 as an example, and the total rated current is denoted as I. ac The maximum current is denoted as I. cap The three transformers are designated as Transformer 1, Transformer 2, and Transformer 3. The double-section busbars include the First Busbar and the Second Busbar. The incoming line groups include the First Incoming Line Group and the Second Incoming Line Group. The double-section busbar and incoming line group corresponding to Transformer 1 are designated as the First Double-Section Busbar and the First Incoming Line Group, respectively; the double-section busbar and incoming line group corresponding to Transformer 2 are designated as the Second Double-Section Busbar and the Second Incoming Line Group, respectively; and the double-section busbar and incoming line group corresponding to Transformer 3 are designated as the Third Double-Section Busbar and the Third Incoming Line Group, respectively. The current of the first incoming line group of the First Incoming Line Group is denoted as I. 11 The current of the second incoming group of the first incoming group is denoted as I. 12 The current of the first incoming group of the second incoming group is denoted as I. 21 The current of the second incoming line subgroup of the second incoming line group is denoted as I. 22 The current of the first incoming group of the third incoming group is denoted as I. 31 The current of the second incoming subgroup of the third incoming line group is denoted as I. 32 .

[0096] In this embodiment of the invention, if the operating state is that one of the busbars in any set of double-section busbars in the AC field module has a fault or is under maintenance, and the busbar of the double-section busbar that has a fault or is under maintenance is denoted as the second busbar, then the switching elements that control the first busbar of the double-section busbar to be connected to the corresponding first incoming line group, the second incoming line group and the two sets of grid-side windings of the transformer are closed, and the second busbar of the double-section busbar is disconnected from the switching elements that control the corresponding first incoming line group, the second incoming line group and the two sets of grid-side windings of the transformer are connected to the corresponding first incoming line group, the second incoming line group and the two sets of grid-side windings of the transformer.

[0097] The switching elements that control the normal operation of other groups of double-section busbars are connected to the first incoming group of the corresponding incoming group and a group of grid-side windings of the corresponding transformer, respectively. The switching elements that control the normal operation of other groups of double-section busbars are connected to the second incoming group of the corresponding incoming group and another group of grid-side windings of the corresponding transformer, respectively.

[0098] The control wiring components in the wiring assembly are disconnected to disconnect all busbars, and the current supplied to each subgroup of each incoming line group is controlled to not exceed I. ac / 2N;

[0099] Furthermore, the first switching element connecting each incoming line group to each busbar, the second switching element connecting each busbar to the transformer grid winding, and the connection element connecting any two busbars in the offshore wind power DC transmission converter station wiring system are disconnected.

[0100] It should be noted that when one busbar of the offshore wind power DC transmission converter station connection system is unavailable, taking the unavailability of the second busbar of the first double-section busbar as an example, the second incoming line group 11-2 of the wind farm and the grid-side winding incoming line group of the first transformer 31-1, which were originally connected to the second busbar of the first double-section busbar, are all reconnected to the first busbar of the first double-section busbar. At this time, the current of each incoming line group of the wind farm and the current of each grid-side winding incoming line group of each transformer can still not exceed I. ac / 6, and it will not exceed I. cap .

[0101] like Figure 1 and Figure 4 As shown in this embodiment of the invention, if the first transformer is in a faulty or under-maintenance state, the following are controlled: the switching element connecting the first incoming group of each incoming line group to the first busbar of the corresponding double-section busbar is closed; the switching element connecting the second incoming group of each incoming line group to the second busbar of the corresponding double-section busbar is closed; the wiring element connecting the first busbar of the first double-section busbar to the first busbar of the second double-section busbar is closed; the wiring element connecting the second busbar of the first double-section busbar to the second busbar of the third double-section busbar is closed; the switching element connecting one set of grid-side windings of the second and third transformers to the first busbar of the corresponding double-section busbar is closed; the switching element connecting the other set of grid-side windings of the second and third transformers to the second busbar of the corresponding double-section busbar is closed; and the transmission current of the second incoming group of the second incoming line group and the first incoming group of the third incoming line group is not greater than I. cap The transmission current of the first incoming group of the second incoming line group and the second incoming group of the third incoming line group shall not exceed (I ac / 3-I capThe system controls the transmission current of the first incoming line subgroup of the first incoming line group to be no greater than the first current threshold, and controls the transmission current of the second incoming line subgroup of the first incoming line group to be no greater than the second current threshold; and controls the disconnection of the first switching element connecting each other incoming line subgroup to each busbar, the second switching element connecting each busbar to the transformer grid-side winding, and the connection element connecting any two busbars in the wiring system of the offshore wind power DC transmission converter station. If the first transformer is faulty or under maintenance, the following can be controlled: the switching element connecting the first incoming group of each incoming line group to the first busbar of the corresponding double-section busbar can be closed; the switching element connecting the second incoming group of each incoming line group to the second busbar of the corresponding double-section busbar can be closed; the wiring element connecting the second busbar of the first double-section busbar to the second busbar of the second double-section busbar can be closed; the wiring element connecting the first busbar of the first double-section busbar to the first busbar of the third double-section busbar can be closed; the switching element connecting one set of grid-side windings of the second and third transformers to the first busbar of the corresponding double-section busbar can be closed; the switching element connecting the other set of grid-side windings of the second and third transformers to the second busbar of the corresponding double-section busbar can be closed; and the transmission current of the first incoming group of the second incoming line group and the second incoming group of the third incoming line group should not exceed I. cap The transmission current of the second incoming line subgroup of the second incoming line group and the first incoming line subgroup of the third incoming line group shall not exceed (I ac / 3-I cap The system controls the transmission current of the second incoming group of the first incoming line group to be no greater than the first current threshold, and controls the transmission current of the first incoming group of the first incoming line group to be no greater than the second current threshold; and controls the disconnection of the first switching element connected to each busbar, the second switching element connected to the transformer grid-side winding, and the connection element connected to any two busbars in the wiring system of the offshore wind power DC transmission converter station.

[0102] It should be noted that when one transformer in the offshore wind power DC transmission converter station wiring system is unavailable, taking the first transformer 31-1 as an example, by closing the connection elements between the first busbar of the first double-section busbar and the first busbar of the second double-section busbar, and the connection elements between the second busbar of the first double-section busbar and the second busbar of the third double-section busbar, the current of the first incoming group of the first incoming line group in the wind farm is transferred to the first busbar of the second double-section busbar and transmitted through the second transformer 31-2. At the same time, the current of the second incoming group of the first incoming line group in the wind farm is transferred to the second busbar of the third double-section busbar and transmitted through the third transformer 31-3. At this time, the current of each grid-side winding incoming group of the second transformer 31-2 and each grid-side winding incoming group of the third transformer 31-3 may exceed the maximum current I. cap Comprehensive control of I is required 11 I21 I 22 and I 12 I 31 I 32 Within the maximum current I cap Under the premise of sufficient capacity, the transmission capacity of the offshore wind power DC transmission converter station wiring system should be fully utilized. Specifically, it is assumed that the actual total operating current of the first and second incoming line groups of the second incoming line group are I' respectively. 21 、I' 22 By adjusting the incoming line combination of the first and second incoming line groups of the second incoming line group, I... 22 Adjusted to I cap , will I 21 Adjust to I' 21 +I' 22 -I cap , and I 11 Will be adjusted to ≤2I cap -I 21 -I 22 Similarly, suppose the actual total operating current of the first and second incoming line groups of the third incoming line group are I' and I', respectively. 31 、I' 32 By adjusting the incoming line combination of the first and second incoming line groups of the third incoming line group, I... 31 Adjusted to I cap , will I 32 Adjust to I' 31 +I' 32 -I cap and I 12 Adjust to ≤2I cap -I 31 -I 32 In this offshore wind power DC transmission converter station wiring system, based on the actual transmission current, priority is given to arranging the second incoming line group of the second incoming line group or the first incoming line group of the third incoming line group to transmit first. If the actual transmission current is greater than I... cap Then the operating current controlling the second incoming line subgroup of the second incoming line group and the first incoming line subgroup of the third incoming line group is I. cap The operating current of the first incoming line group of the second incoming line group and the second incoming line group of the third incoming line group is controlled to be the actual transmission current minus I. cap And the maximum operating current does not exceed (I ac / 3-I cap If the actual transmission current is not greater than I; capIf the operating current of the second incoming group of the second incoming line group and the first incoming group of the third incoming line group is the actual transmission current, then the operating current of the first incoming group of the second incoming line group and the second incoming group of the third incoming line group is 0, meaning no operation is required. Alternatively, by closing the connection elements between the second busbars of the first double-section busbar and the second busbar of the second double-section busbar, and between the first busbar of the first double-section busbar and the first busbar of the third double-section busbar, the current of the first incoming group of the first incoming line group in the wind farm can be transferred to the second busbar of the second double-section busbar and transmitted through the second transformer 31-2. At the same time, the current of the second incoming group of the first incoming line group in the wind farm can be transferred to the first busbar of the third double-section busbar and transmitted through the third transformer 31-3. At this time, the current of each grid-side winding incoming group of the second transformer 31-2 and each grid-side winding incoming group of the third transformer 31-3 may exceed the maximum current I. cap Comprehensive control of I is required 11 I 21 I 22 and I 12 I 31 I 32 Within the maximum current I cap Under the premise of sufficient capacity, the transmission capacity of the offshore wind power DC transmission converter station wiring system should be fully utilized. Specifically, it is assumed that the actual total operating current of the first and second incoming line groups of the second incoming line group are I' respectively. 21 、I' 22 By adjusting the incoming line combination of the first and second incoming line groups of the second incoming line group, I... 21 Adjusted to I cap , will I 21 Adjust to I' 21 +I' 22 -I cap , and I 12 Will be adjusted to ≤2I cap -I 21 -I 22 Similarly, suppose the actual total operating current of the first and second incoming line groups of the third incoming line group are I' and I', respectively. 31 、I' 32 By adjusting the incoming line combination of the first and second incoming line groups of the third incoming line group, I... 32 Adjusted to I cap , will I 31 Adjust to I' 31 +I' 32 -I cap and I 11 Adjust to ≤2I cap -I 31 -I 32In this offshore wind power DC transmission converter station wiring system, based on the actual transmission current, priority is given to either the first incoming group of the second incoming group or the second incoming group of the third incoming group for transmission. If the actual transmission current is greater than I... cap Then the operating current controlling the first incoming group of the second incoming line group and the second incoming group of the third incoming line group is I. cap The operating current of the second incoming line subgroup of the second incoming line group and the first incoming line subgroup of the third incoming line group is controlled to be the actual transmission current minus I. cap And the maximum operating current does not exceed (I ac / 3-I cap If the actual transmission current is not greater than I; cap If the operating current of the first incoming group of the second incoming line group and the second incoming group of the third incoming line group is the actual transmission current, then the operating current of the second incoming group of the second incoming line group and the first incoming group of the third incoming line group is 0, meaning they do not need to work.

[0103] like Figure 1 and Figure 4 As shown in this embodiment of the invention, if the second transformer is in a faulty or under-maintenance state, the following actions are taken: First, the switching element connecting the first incoming group of each incoming line group to the first busbar of the corresponding double-section busbar is closed; second, the switching element connecting the second incoming group of each incoming line group to the second busbar of the corresponding double-section busbar is closed; third, the wiring element connecting the first busbar of the first double-section busbar to the first busbar of the second double-section busbar is closed; fourth, the wiring element connecting the second busbar of the second double-section busbar to the second busbar of the third double-section busbar is closed; fifth, the switching element connecting one set of grid-side windings of the first and third transformers to the first busbar of the corresponding double-section busbar is closed; sixth, the switching element connecting the other set of grid-side windings of the first and third transformers to the second busbar of the corresponding double-section busbar is closed; and seventh, the transmission current of the second incoming group of the first incoming line group and the first incoming group of the third incoming line group is controlled to be no greater than I... cap The transmission current of the first incoming line subgroup of the first incoming line group and the second incoming line subgroup of the third incoming line group shall not exceed (I ac / 3-I capThe system controls the transmission current of the first incoming group of the second incoming group to be no greater than the third current threshold, and controls the transmission current of the second incoming group of the second incoming group to be no greater than the second current threshold; and controls the disconnection of the first switching element connecting each other incoming group to each busbar, the second switching element connecting each busbar to the transformer grid winding, and the connection element connecting any two busbars in the wiring system of the offshore wind power DC transmission converter station. Alternatively, if the second transformer is faulty or under maintenance, the following can be controlled: the switching element connecting the first incoming group of each incoming line group to the first busbar of the corresponding double-section busbar can be closed; the switching element connecting the second incoming group of each incoming line group to the second busbar of the corresponding double-section busbar can be closed; the wiring element connecting the second busbar of the first double-section busbar to the second busbar of the second double-section busbar can be closed; the wiring element connecting the first busbar of the second double-section busbar to the first busbar of the third double-section busbar can be closed; the switching element connecting one set of grid-side windings of the first and third transformers to the first busbar of the corresponding double-section busbar can be closed; the switching element connecting the other set of grid-side windings of the first and third transformers to the second busbar of the corresponding double-section busbar can be closed; and the transmission current of the first incoming group of the first incoming line group and the second incoming group of the third incoming line group can be controlled to be no greater than I. cap The transmission current of the second incoming subgroup of the first incoming line group and the first incoming subgroup of the third incoming line group are both not greater than (I ac / 3-I cap The system controls the transmission current of the second incoming group of the second incoming group to be no greater than the third current threshold, and controls the transmission current of the first incoming group of the second incoming group to be no greater than the second current threshold; and controls the disconnection of the first switching element connecting each other incoming group to each busbar, the second switching element connecting each busbar to the transformer grid winding, and the connection element connecting any two busbars in the wiring system of the offshore wind power DC transmission converter station.

[0104] It should be noted that when one transformer in the offshore wind power DC transmission converter station wiring system is unavailable, taking the unavailability of the second transformer 31-2 as an example, by closing the connection elements between the first busbar of the first double-section busbar and the first busbar of the second double-section busbar, and the connection elements between the second busbar of the second double-section busbar and the second busbar of the third double-section busbar, the current of the first incoming group of the second incoming group in the wind farm is transferred to the first busbar of the first double-section busbar and transmitted through the first transformer 31-1. At the same time, the current of the second incoming group of the second incoming group in the wind farm is transferred to the second busbar of the third double-section busbar and transmitted through the third transformer 31-3. At this time, the current of each grid-side winding incoming group of the first transformer 31-1 and each grid-side winding incoming group of the third transformer 31-3 may exceed the maximum current I. cap Comprehensive control of I is required 11 I21 I 12 and I 22 I 31 I 32 Within the maximum current I cap Under the premise of sufficient capacity, fully utilize the transmission capacity of the offshore wind power DC transmission converter station wiring system. Specifically: assuming the actual total operating current of the first incoming line group and the second incoming line group of the first incoming line group are I' 11 、I' 12 By adjusting the incoming line combination of the first and second incoming line groups of the incoming line group in Figure I, the I... 12 Adjusted to I cap , will I 11 Adjust to I' 11 +I' 12 -I cap , and I 21 Will be adjusted to ≤2I cap -I 11 -I 12 Similarly, suppose the actual total operating current of the first and second incoming line groups of the third incoming line group are I' and I', respectively. 31 、I' 32 By adjusting the incoming line combination of the first and second incoming line groups of the third incoming line group, I... 31 Adjusted to I cap , will I 32 Adjust to I' 31 +I' 32 -I cap and I 12 Adjust to ≤2I cap -I 31 -I 32 In this offshore wind power DC transmission converter station wiring system, based on the actual transmission current, priority is given to arranging the second incoming line group of the first incoming line group and the second incoming line group of the third incoming line group to transmit first. If the actual transmission current is greater than I... cap Then the operating current controlling the second incoming subgroup of the first incoming line group and the first incoming subgroup of the third incoming line group is I. cap The control of the first incoming line subgroup of the first incoming line group and the second incoming line subgroup of the third incoming line group is the actual transmitted current minus I. cap And the maximum operating current does not exceed (I ac / 3-I cap If the actual transmission current is not greater than I; capIf the operating current of the second incoming subgroup of the first incoming line group and the first incoming subgroup of the third incoming line group is the actual transmission current, then the operating current of the first incoming subgroup of the first incoming line group and the second incoming subgroup of the third incoming line group is 0, meaning they do not need to work.

[0105] like Figure 1 and Figure 4 As shown in this embodiment of the invention, if the third transformer is in a faulty or under-maintenance state, the following switches are activated: The first incoming group of the second and third incoming groups is connected to the first busbar of the corresponding double-section busbar; the second incoming group of the second and third incoming groups is connected to the second busbar of the corresponding double-section busbar; the two incoming groups of the first incoming group are connected to the first busbar of the first double-section busbar; the wiring elements connecting the second busbar of the first double-section busbar to the second busbar of the third double-section busbar are closed; the wiring elements connecting the first busbar of the second double-section busbar to the first busbar of the third double-section busbar are closed; the switching elements connecting one set of grid-side windings of the first and second transformers to the first busbar of the corresponding double-section busbar are closed; the switching elements connecting the other set of grid-side windings of the first and second transformers to the second busbar of the corresponding double-section busbar are closed; and the current supplied by the first incoming group of the first incoming group and the second incoming group of the second incoming group of the second incoming group is not greater than I. cap The transmission current of the second incoming group of the first incoming line group and the first incoming group of the second incoming line group of the second incoming line group are both not greater than (I ac / 3-I cap The system controls the transmission current of the first incoming group of the third incoming line group to be no greater than a first current threshold, and controls the transmission current of the second incoming group of the third incoming line group to be no greater than a third current threshold. Furthermore, it controls the disconnection of the first switching element connecting each other incoming group to each busbar, the second switching element connecting each busbar to the transformer grid winding, and the connection element connecting any two busbars in the offshore wind power DC transmission converter station wiring system. The first current threshold is 2I. cap -I 21 -I 22 I 21 For the transmission current of the first incoming group of the second incoming group, I 22 The current supplied to the second incoming group of the second incoming group; the second current threshold is 2I. cap -I 31 -I 32 I 31 For the transmission current of the first incoming group of the third incoming group, I 32 The current supplied to the second incoming group of the third incoming group; the third current threshold is 2I. cap -I11 -I 12 I 11 For the transmission current of the first incoming line group of the first incoming line group, I 12 This refers to the current supplied to the second incoming group of the first incoming group. Therefore, the current threshold can be summarized as 2I. cap Subtract the total current of the incoming line group corresponding to the dual-section busbar that receives the transferred power.

[0106] If the third transformer is faulty or under maintenance, the following can be controlled: the switching element connecting the first incoming group of each incoming line group to the first busbar of the corresponding double-section busbar can be closed; the switching element connecting the second incoming group of each incoming line group to the second busbar of the corresponding double-section busbar can be closed; the wiring element connecting the first busbar of the first double-section busbar to the first busbar of the third double-section busbar can be closed; the wiring element connecting the second busbar of the second double-section busbar to the second busbar of the third double-section busbar can be closed; the switching element connecting one set of grid-side windings of the first and second transformers to the first busbar of the corresponding double-section busbar can be closed; the switching element connecting the other set of grid-side windings of the first and second transformers to the second busbar of the corresponding double-section busbar can be closed; and the transmission current of the second incoming group of the first incoming line group and the first incoming group of the second incoming line group of the first incoming line group should not exceed I. cap The transmission current of the first incoming line subgroup of the first incoming line group and the second incoming line subgroup of the second incoming line group of the second incoming line group shall not exceed (I ac / 3-I cap The system controls the transmission current of the second incoming group of the third incoming group to be no greater than the first current threshold, and controls the transmission current of the first incoming group of the third incoming group to be no greater than the third current threshold; and controls the disconnection of the first switching element connecting each other incoming group to each busbar, the second switching element connecting each busbar to the transformer grid winding, and the connection element connecting any two busbars in the wiring system of the offshore wind power DC transmission converter station.

[0107] It should be noted that when one transformer in the DC transmission converter station wiring system of this offshore wind power is unavailable, taking the unavailability of the third transformer 31-3 as an example, by closing the connection elements between the first busbar of the second double-section busbar and the first busbar of the third double-section busbar, and the connection elements between the second busbar of the first double-section busbar and the second busbar of the third double-section busbar, the current of the first incoming group of the third incoming group in the wind farm is transferred to the first busbar of the second double-section busbar and transmitted through the second transformer 31-2. At the same time, the current of the second incoming group of the third incoming group in the wind farm is transferred to the second busbar of the first double-section busbar and transmitted through the first transformer 31-1. At this time, the current of each grid-side winding incoming group of the second transformer 31-2 and each grid-side winding incoming group of the first transformer 31-1 may exceed the maximum current I. capComprehensive control of I is required 11 I 12 I 32 and I 21 I 31 I 22 Within the maximum current I cap Under the premise of sufficient capacity, fully utilize the transmission capacity of the offshore wind power DC transmission converter station wiring system. Specifically: assuming the actual total operating current of the first incoming line group and the second incoming line group of the first incoming line group are I' 11 、I' 12 By adjusting the incoming line combination of the first incoming line group and the second incoming line group of the first incoming line group, I 11 Adjusted to I cap , will I 12 Adjust to I' 11 +I' 12 -I cap , and I 32 Will be adjusted to ≤2I cap -I 11 -I 12 Similarly, suppose the actual total operating current of the first and second incoming line groups of the second incoming line group are I' 21 、I' 22 By adjusting the incoming line combination of the first and second incoming line groups of the second incoming line group, I... 22 Adjusted to I cap , will I 21 Adjust to I' 21 +I' 22 -I cap and I 31 Adjust to ≤2I cap -I 21 -I 22 In this offshore wind power DC transmission converter station wiring system, based on the actual transmission current, priority is given to arranging the first incoming line group of the first incoming line group and the second incoming line group of the second incoming line group to transmit power first. If the actual transmission current is greater than I... cap Then the operating current controlling the first incoming line subgroup of the first incoming line group and the second incoming line subgroup of the second incoming line group is I. cap The operating current of the second incoming group of the first incoming line group and the first incoming group of the second incoming line group of the second incoming line group is controlled to be the actual transmission current minus I. cap And the maximum operating current does not exceed (I ac / 3-I cap If the actual transmission current is not greater than I... capIf the operating current of the first incoming line subgroup of the first incoming line group and the second incoming line subgroup of the second incoming line group of the second incoming line group is the actual transmission current, then the operating current of the second incoming line subgroup of the first incoming line group and the first incoming line subgroup of the second incoming line group of the second incoming line group is 0, that is, no operation is required.

[0108] In this embodiment of the invention, the control method of the offshore wind power DC transmission converter station wiring system adopts a method in which transformers with two sets of grid-side windings, two busbars, and the wind farm incoming line group are all connected to N sets of double-section busbars. By using multiple busbars of N sets of double-section busbars to carry current during the operation of offshore wind power DC transmission, the current carrying requirements of equipment such as transformer modules and AC field modules can be reduced by half, solving the problem of difficult selection of AC equipment. This makes the control method of the offshore wind power DC transmission converter station wiring system applicable to the electrical wiring of offshore wind power DC transmission converter stations that do not require offshore substations. The control method of the offshore wind power DC transmission converter station wiring system is also applicable to the AC side wiring of offshore substations with larger capacity.

[0109] Example 3:

[0110] This invention also provides a terminal device, including a processor and a memory;

[0111] Memory is used to store program code and transfer the program code to the processor;

[0112] The processor is used to execute the control method of the offshore wind power DC transmission converter station wiring system as described above, according to the instructions in the program code.

[0113] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0114] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection between apparatuses or units through some interfaces, and may be electrical, mechanical, or other forms.

[0115] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0116] Furthermore, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0117] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0118] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A control method for a DC transmission converter station wiring system for offshore wind power, characterized in that, Includes the following steps: Obtain the rated transmission power of the offshore wind power DC system, the rated AC voltage of the wind farm, and the maximum current that the AC field modules are allowed to carry; Based on the rated transmission power, the rated AC voltage, and the maximum current, the total rated current and the number of transformers on the AC side of the AC field module are calculated. The number of dual-section busbars and the number of incoming line groups of the offshore wind power DC system are determined based on the number of transformers; and the wiring is carried out according to the offshore wind power DC transmission converter station wiring system based on the number of transformers, the number of dual-section busbars and the number of incoming line groups. Obtain the operating status of the AC field module in the wiring system of the offshore wind power DC transmission converter station; According to the operating status, control the closing or opening of the wiring elements of the AC field module and the switching elements connected to the AC field module in the offshore wind power DC transmission converter station wiring system, and control the current transmitted by each incoming line group so as to enable the offshore wind power DC transmission converter station wiring system to transmit power normally. Wherein, the number of transformers, the number of double-section busbars, and the number of incoming line groups are all the same and denoted as N, where N is a natural number greater than 1; the offshore wind power DC transmission converter station wiring system includes a wind farm, an AC field module connected to the wind farm, a transformer module connected to the AC field module, a converter module connected to the transformer module, and a DC field module connected to the converter module. The AC field module includes at least N sets of double-section busbars and wiring assemblies connecting adjacent, first and last, or adjacent sets of double-section busbars. The transformer module includes a transformer connected to each set of double-section busbars. The wind farm is provided with incoming line groups connected to each set of double-section busbars. The transformer includes two sets of grid-side windings and one set of valve-side windings. The incoming line groups include two sets of incoming line subgroups. Each set of double-section busbars includes two busbars. Each busbar is connected to the incoming line subgroup of the corresponding incoming line group and the two sets of grid-side windings of the transformer. The valve-side winding of the transformer is connected to the corresponding converter module.

2. The control method for the offshore wind power DC transmission converter station wiring system according to claim 1, characterized in that, If the two sets of double-section busbars connected by the wiring assembly are a first double-section busbar and a second double-section busbar, the wiring assembly includes a first wiring element and a second wiring element. The first end of the first wiring element is connected to the first busbar of the first double-section busbar, and the second end of the first wiring element is connected to the first busbar of the second double-section busbar. The first end of the second wiring element is connected to the second busbar of the first double-section busbar, and the second end of the second wiring element is connected to the second busbar of the second double-section busbar. The wiring element is a circuit breaker or a disconnecting switch.

3. The control method for the offshore wind power DC transmission converter station wiring system according to claim 1, characterized in that, A first switching element is provided between the incoming line group of the incoming line group and the corresponding busbar connection. A second switching element is also provided between each busbar and the grid-side winding of the corresponding transformer. A third switching element is also provided between the valve-side winding of the transformer and the converter module connection.

4. The control method for the offshore wind power DC transmission converter station wiring system according to claim 1, characterized in that, The transformer is a three-phase transformer.

5. The control method for the wiring system of the offshore wind power DC transmission converter station according to claim 1, characterized in that, When the offshore wind power DC transmission converter station connection system is operating normally, the rated power of each incoming line group is distributed equally according to the total rated power of the wind farm.

6. The control method for the wiring system of the offshore wind power DC transmission converter station according to claim 1, characterized in that, The double-section busbar includes the first busbar and the second busbar, and the incoming line group includes the first incoming line group and the second incoming line group. The total rated current is denoted as I. ac If the operating state is that the AC field module is in normal working state, then the switching elements connecting the first busbar of each group of double-section busbars to the first incoming subgroup of the corresponding incoming line group and a set of grid-side windings of the corresponding transformer are closed; the switching elements connecting the second busbar of each group of double-section busbars to the second incoming subgroup of the corresponding incoming line group and another set of grid-side windings of the corresponding transformer are closed; the wiring elements in the wiring assembly are disconnected to disconnect all the busbars; and the transmission current of each incoming subgroup of each group of the incoming line group is controlled not to exceed I. ac / 2N.

7. The control method for the wiring system of the offshore wind power DC transmission converter station according to claim 1, characterized in that, The total rated current is denoted as I. ac The double-section busbar includes a first busbar and a second busbar, and the incoming line group includes a first incoming line group and a second incoming line group. If the operating state is that one busbar in any group of double-section busbars in the AC field module is faulty or under maintenance, and the busbar of the double-section busbar that is faulty or under maintenance is denoted as the second busbar, then the switching elements controlling the first busbar of the double-section busbar to be connected to the corresponding first incoming line group, the second incoming line group and the two groups of grid-side windings of the transformer are closed, and the second busbar of the double-section busbar is disconnected from the switching elements connecting the corresponding first incoming line group, the second incoming line group and the two groups of grid-side windings of the transformer. The switching elements that control the normal operation of other groups of double-section busbars are connected to the first incoming group of the corresponding incoming group and a set of grid-side windings of the corresponding transformer, respectively. The switching elements that control the normal operation of other groups of double-section busbars are connected to the second incoming group of the corresponding incoming group and another set of grid-side windings of the corresponding transformer, respectively. The wiring elements in the control wiring assembly are disconnected to disconnect all the busbars, and the transmission current of each group of incoming lines in each group of incoming lines is controlled to be no greater than I. ac / 2N.

8. The control method for the wiring system of the offshore wind power DC transmission converter station according to claim 1, characterized in that, The total rated current is denoted as I. ac The maximum current is denoted as I. cap N transformers are designated as Transformer 1, Transformer n, and Transformer N, respectively. The double-section busbar includes a first busbar and a second busbar. The incoming line group includes a first incoming line group and a second incoming line group. The double-section busbar and incoming line group corresponding to Transformer 1 are designated as the first double-section busbar and the first incoming line group, respectively; the double-section busbar and incoming line group corresponding to Transformer n are designated as the nth double-section busbar and the nth incoming line group, respectively; and the double-section busbar and incoming line group corresponding to Transformer N are designated as the Nth double-section busbar and the Nth incoming line group, respectively. The double-segment busbar adjacent to the first double-segment busbar is denoted as the second double-segment busbar; The operating state is when any transformer fails or is under maintenance, the switching element connecting the first incoming group of each incoming line group to the first busbar of the corresponding double-section busbar is closed, and the switching element connecting the second incoming group of each incoming line group to the second busbar of the corresponding double-section busbar is closed; the switching element connecting one set of grid-side windings of other normal transformers to the first busbar of the corresponding double-section busbar is closed, and the switching element connecting the other set of grid-side windings of other normal transformers to the second busbar of the corresponding double-section busbar is closed. If the operating state is that the first transformer has failed or is under maintenance, the connection element connecting the first busbar of the first double-section busbar to the first busbar of the second double-section busbar, and the connection element connecting the second busbar of the first double-section busbar to the second busbar of the Nth double-section busbar, are also controlled to close, and the transmission current of the second incoming subgroup of the second incoming line group and the first incoming subgroup of the Nth incoming line group is controlled to be no greater than I. cap The transmission current of the first incoming group of the second incoming line group and the second incoming group of the Nth incoming line group is controlled to be no greater than (I ac / 3-I cap The current supplied to the two groups of incoming lines in the first incoming line group is controlled to be no greater than the current threshold. The current supplied to each group of incoming lines in all other incoming line groups (excluding the first, second, and Nth incoming line groups) is no greater than I. ac / 2N; or control the closing of the connection element connecting the second busbar of the first double-section busbar to the second busbar of the second double-section busbar and the closing of the connection element connecting the first busbar of the first double-section busbar to the first busbar of the Nth double-section busbar; control the transmission current of the first incoming group of the second incoming group and the second incoming group of the Nth incoming group to be no greater than I cap The transmission current of the second incoming line subgroup of the second incoming line group and the first incoming line subgroup of the Nth incoming line group is controlled to be no greater than (I ac / 3-I cap The current supplied to the two subgroups of the first incoming line group is controlled to be no greater than the current threshold; the current supplied to each subgroup of the incoming line group other than the first, second, and Nth incoming line groups is controlled to be no greater than I. ac / 2N; If the operating state is that the nth transformer has failed or is under maintenance, the connection element connecting the first busbar of the nth double-section busbar to the first busbar of the (n-1)th double-section busbar, and the connection element connecting the second busbar of the nth double-section busbar to the second busbar of the (n+1)th double-section busbar, are also controlled to close; the transmission current of the second incoming subgroup of the (n-1)th incoming line group and the first incoming subgroup of the (n+1)th incoming line group is controlled to be no greater than I. cap The transmission current of the first incoming subgroup of the (n-1)th incoming line group and the second incoming subgroup of the (n+1)th incoming line group is controlled to be no greater than (I ac / 3-I cap The current transmitted by the two groups of incoming lines in the nth incoming line group is controlled to be no greater than the current threshold, and the current transmitted by each group of incoming lines in the incoming line groups other than the (n-1)th, nth, and (n+1)th incoming line groups is no greater than I. ac / 2N; or control the closing of the wiring element connecting the second busbar of the nth double-section busbar to the second busbar of the (n-1)th double-section busbar and the closing of the wiring element connecting the first busbar of the nth double-section busbar to the first busbar of the (n+1)th double-section busbar; control the transmission current of the first incoming group of the (n-1)th incoming group and the second incoming group of the (n+1)th incoming group to be no greater than I cap The transmission current of the second incoming subgroup of the (n-1)th incoming line group and the first incoming subgroup of the (n+1)th incoming line group is controlled to be no greater than (I ac / 3-I cap The current transmitted by the two groups of incoming lines in the nth incoming line group is controlled to be no greater than the current threshold, and the current transmitted by each group of incoming lines in the incoming line groups other than the (n-1)th, nth, and (n+1)th incoming line groups is no greater than I. ac / 2N; If the operating state is that the Nth transformer has failed or is under maintenance, the connection element connecting the second busbar of the first double-section busbar to the second busbar of the Nth double-section busbar and the connection element connecting the first busbar of the (N-1)th double-section busbar to the first busbar of the Nth double-section busbar are also controlled to close; the transmission current of the first incoming line group of the first incoming line group and the second incoming line group of the (N-1)th incoming line group is controlled to be no greater than I. cap The transmission current of the second incoming group of the first incoming line group and the first incoming group of the (N-1)th incoming line group is controlled to be no greater than (I ac / 3-I cap The current supplied to the two groups of incoming lines in the Nth incoming line group is controlled to be no greater than the current threshold. The current supplied to each group of incoming lines in the incoming line groups other than the first, (N-1), and Nth incoming line groups is no greater than I. ac / 2N; or control the connection element connecting the first busbar of the first double-section busbar to the first busbar of the Nth double-section busbar to close, and control the connection element connecting the second busbar of the N-1th double-section busbar to the second busbar of the Nth double-section busbar to close; control the transmission current of the second incoming group of the first incoming group and the first incoming group of the N-1th incoming group to be no greater than I cap The transmission current of the first incoming line subgroup of the first incoming line group and the second incoming line subgroup of the (N-1)th incoming line group is controlled to be no greater than (I ac / 3-I cap The current supplied to the two subgroups of the Nth incoming line group is controlled to be no greater than the current threshold, and the current supplied to each subgroup of the incoming line group other than the first incoming line group, the (N-1)th incoming line group, and the Nth incoming line group is no greater than I. ac / 2N; Wherein, the current threshold is 2I cap Subtract the total current of the incoming line group corresponding to the dual-section busbar that receives the transferred power.

9. A terminal device, characterized in that, Including the processor and memory; The memory is used to store program code and transmit the program code to the processor; The processor is configured to execute the control method for the offshore wind power DC transmission converter station wiring system as described in any one of claims 1-8, according to the instructions in the program code.

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