CN116722575A - Method and device for starting offshore wind power direct-current transmission system with direct-current bypass switch - Google Patents
Method and device for starting offshore wind power direct-current transmission system with direct-current bypass switch Download PDFInfo
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- CN116722575A CN116722575A CN202311002633.1A CN202311002633A CN116722575A CN 116722575 A CN116722575 A CN 116722575A CN 202311002633 A CN202311002633 A CN 202311002633A CN 116722575 A CN116722575 A CN 116722575A
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- 238000002955 isolation Methods 0.000 claims description 14
- 238000005265 energy consumption Methods 0.000 claims description 7
- 238000006243 chemical reaction Methods 0.000 claims description 4
- 238000004590 computer program Methods 0.000 claims description 3
- 238000010586 diagram Methods 0.000 description 5
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Classifications
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/36—Arrangements for transfer of electric power between ac networks via a high-tension dc link
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
- H02J3/381—Dispersed generators
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J2300/00—Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation
- H02J2300/20—The dispersed energy generation being of renewable origin
- H02J2300/28—The renewable source being wind energy
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/60—Arrangements for transfer of electric power between AC networks or generators via a high voltage DC link [HVCD]
Abstract
The application relates to the technical field of offshore direct current transmission, and provides a method and a device for starting an offshore wind power direct current transmission system with a direct current bypass switch. The method comprises the following steps: controlling a land converter station to charge an offshore auxiliary soft direct current converter valve in the offshore converter station so that the offshore auxiliary soft direct current converter valve starts an offshore wind farm; controlling the output power of the offshore wind farm until the current value passing through the first bypass switch and the second bypass switch is smaller than a preset current value, and switching off the first bypass switch and the second bypass switch; and (5) switching on the first diode valve and the second diode valve in the offshore converter station to finish the starting of the offshore wind power direct current transmission system. The application provides a starting method of an offshore wind power direct current transmission system with a direct current bypass switch.
Description
Technical Field
The application relates to the technical field of offshore direct current transmission, in particular to a method and a device for starting an offshore wind power direct current transmission system with a direct current bypass switch.
Background
The offshore wind power put into operation is mostly sent out by adopting flexible direct current, but the offshore flexible direct current conversion platform has overlarge volume and weight and high manufacturing cost. In order to achieve compactness and light weight of the offshore converter platform and reduce the cost of the offshore converter valve, the industry explores the technology of directly sending out the offshore wind power through uncontrolled rectification. The technology mainly has two routes, one is that an offshore converter valve adopts a pure diode; one is a hybrid valve consisting of diodes and auxiliary modular multilevel converters (Modular Multilevel Converter, MMC).
In comparison, the cost, volume and weight of the hybrid valve are lower than that of a pure soft direct current converter valve and higher than that of a pure diode valve, but the degree of the improvement depends on the duty ratio of the auxiliary MMC; meanwhile, compared with a pure diode valve, the hybrid valve can greatly reduce the investment and the occupied area of a passive filter, and in the aspect of performance, the hybrid valve has the advantages of starting an offshore wind power plant, active filtering, providing a certain degree of reactive compensation and resonance suppression means and the like due to the auxiliary MMC of the hybrid valve.
In the prior art, in order to reduce the volume of the converter valve and reduce the cost of the converter valve, a mode of connecting an auxiliary MMC and a diode valve in series on a direct current side is adopted, and a direct current bypass switch is arranged at the same time, but the starting method of the existing offshore wind power direct current transmission system is not suitable for the system due to the change of a topological structure.
Disclosure of Invention
The application provides a starting method and device for an offshore wind power direct current transmission system with a direct current bypass switch, which are used for solving the problem that the starting method is not suitable for the offshore wind power direct current transmission system with the direct current bypass switch in the related art.
In a first aspect, the application provides a method for starting an offshore wind power direct current transmission system with a direct current bypass switch, which is applied to the offshore wind power direct current transmission system with the direct current bypass switch, wherein the system comprises a land converter station, an offshore wind farm and an offshore alternating current bus; the offshore converter station comprises an offshore auxiliary soft direct current converter valve, a first diode valve and a second diode valve which are connected in series with the offshore auxiliary soft direct current converter valve; the offshore auxiliary soft direct current converter valve and the first diode valve are respectively connected with one end of the land-based converter station, and a first bypass switch is connected between the offshore auxiliary soft direct current converter valve and one end of the land-based converter station; the offshore auxiliary soft direct current converter valve and the second diode valve are respectively connected with the other end of the land-based converter station, and a second bypass switch is connected between the offshore auxiliary soft direct current converter valve and the other end of the land-based converter station; the first diode valve, the offshore auxiliary soft direct current converter valve and the second diode valve are respectively connected with an offshore alternating current bus; the offshore alternating current bus is connected with an offshore wind farm;
the method comprises the following steps:
controlling a land converter station to charge an offshore auxiliary soft direct current converter valve in the offshore converter station so that the offshore auxiliary soft direct current converter valve starts an offshore wind farm;
controlling the output power of the offshore wind farm until the current value passing through the first bypass switch and the second bypass switch is smaller than a preset current value, and switching off the first bypass switch and the second bypass switch;
and (5) switching on the first diode valve and the second diode valve in the offshore converter station to finish the starting of the offshore wind power direct current transmission system.
In view of the above, in order to achieve the light-weight of the offshore wind power direct current delivery system and simultaneously provide a black start function, a direct current bypass switch is provided in the offshore wind power direct current transmission system, but the related start method is not suitable for the system.
In an alternative embodiment, the system further comprises a land grid; the offshore converter station further comprises a first transformer, a second transformer and a third transformer; the land-based converter station comprises a three-winding transformer and a land-based flexible direct current converter valve; the three-winding transformer comprises a network side high-voltage winding, a valve side high-voltage winding and a valve side low-voltage winding, wherein the network side high-voltage winding is connected with a land power grid through a first circuit breaker; the valve side high-voltage winding and the valve side low-voltage winding are connected with the land soft direct current converter valve through a second circuit breaker and a third circuit breaker respectively; the land flexible direct current converter valve is connected with the offshore converter station; the first diode valve is connected with an offshore alternating current bus through a first transformer and a sixth breaker in sequence; the offshore auxiliary soft direct current converter valve is connected with an offshore alternating current bus through a fourth circuit breaker, a second transformer and a fifth circuit breaker in sequence; the second diode valve is connected with an offshore alternating current bus through a third transformer and a seventh breaker in sequence;
controlling an offshore auxiliary soft direct converter valve in an offshore converter station to be charged by an onshore converter station to enable the offshore auxiliary soft direct converter valve to start an offshore wind farm, comprising:
closing the first circuit breaker, the third circuit breaker, the first bypass switch and the second bypass switch to enable the land grid to charge the land soft direct current converter valve in the land converter station through the grid-side high-voltage winding and the valve-side low-voltage winding in the three-winding transformer, and simultaneously charging the sea auxiliary soft direct current converter valve in the sea converter station by the land soft direct current converter valve until the land soft direct current converter valve and the sea auxiliary soft direct current converter valve are charged;
unlocking the land soft direct current converter valve and the marine auxiliary soft direct current converter valve, and setting the direct current voltage value of the land soft direct current converter valve as a preset direct current voltage value;
and closing the fourth circuit breaker, the fifth circuit breaker, the sixth circuit breaker and the seventh circuit breaker, and controlling the offshore auxiliary soft direct current converter valve to enable the voltage value of the offshore alternating current bus to reach the preset offshore alternating current bus voltage, so as to start a preset number of fans in the offshore wind farm.
In an alternative embodiment, controlling the output power of the offshore wind farm until the current value through the first bypass switch and the second bypass switch is less than a preset current value, opening the first bypass switch and the second bypass switch comprises:
and adopting a controllable energy consumption mode for the offshore wind farm to control the active power output by a preset number of fans to the offshore auxiliary soft direct current converter valve, and switching off the first bypass switch and the second bypass switch until the current value passing through the first bypass switch and the second bypass switch is smaller than a preset current value.
In an alternative embodiment, controlling the output power of the offshore wind farm until the current value through the first bypass switch and the second bypass switch is less than a preset current value, opening the first bypass switch and the second bypass switch comprises:
and implementing variable pitch power limiting control on a preset number of fans until the current value passing through the first bypass switch and the second bypass switch is smaller than a preset current value, and switching off the first bypass switch and the second bypass switch.
In an alternative embodiment, a first isolation disconnecting link is connected between one end of the land-based soft direct current converter valve and the first diode valve, and a second isolation disconnecting link is connected between the other end of the land-based soft direct current converter valve and the second diode valve;
the method for starting the offshore wind power direct current transmission system comprises the steps of:
controlling the land soft direct current converter valve to increase the direct current voltage value to the rated direct current voltage value, and switching off the third circuit breaker;
closing the second circuit breaker when the direct current voltage of the land soft direct current converter valve is matched with the voltage of the valve side high voltage winding;
controlling the offshore auxiliary soft direct current converter valve to reduce the direct current voltage value of the offshore converter station, so that the direct current voltage value of the offshore converter station is smaller than the rated direct current voltage value of the onshore soft direct current converter valve, and closing the first isolation disconnecting link and the second isolation disconnecting link;
and controlling the offshore auxiliary soft direct current converter valve to increase the voltage value of the offshore alternating current bus until the first diode valve and the second diode valve are conducted, and starting the offshore wind power direct current transmission system.
In an alternative embodiment, controlling the offshore auxiliary soft direct current converter valve to bring the voltage value of the offshore alternating current bus to a preset offshore alternating current bus voltage includes:
the control offshore auxiliary soft direct current converter valve outputs preset offshore alternating current bus voltage in a zero-starting boosting mode.
In an alternative embodiment, after completing the step of starting the offshore wind power direct current transmission system, the method further comprises, after switching on the first diode valve and the second diode valve in the offshore converter station:
and controlling the output power of the started fans in the offshore wind farm, enabling the started fans to enter a maximum power tracking mode, and starting other fans in the offshore wind farm.
In a second aspect, the application also provides a starting device of the offshore wind power direct current transmission system with the direct current bypass switch, which is applied to the offshore wind power direct current transmission system with the direct current bypass switch, wherein the system comprises a land converter station, an offshore wind farm and an offshore alternating current bus; the offshore converter station comprises an offshore auxiliary soft direct current converter valve, a first diode valve and a second diode valve which are connected in series with the offshore auxiliary soft direct current converter valve; the offshore auxiliary soft direct current converter valve and the first diode valve are respectively connected with one end of the land-based converter station, and a first bypass switch is connected between the offshore auxiliary soft direct current converter valve and one end of the land-based converter station; the offshore auxiliary soft direct current converter valve and the second diode valve are respectively connected with the other end of the land-based converter station, and a second bypass switch is connected between the offshore auxiliary soft direct current converter valve and the other end of the land-based converter station; the first diode valve, the offshore auxiliary soft direct current converter valve and the second diode valve are respectively connected with an offshore alternating current bus; the offshore alternating current bus is connected with an offshore wind farm;
the device comprises:
the first control module is used for controlling the land converter station to charge the offshore auxiliary soft direct current converter valve in the offshore converter station so that the offshore auxiliary soft direct current converter valve starts an offshore wind farm;
the second control module is used for controlling the output power of the offshore wind farm, and switching off the first bypass switch and the second bypass switch until the current value passing through the first bypass switch and the second bypass switch is smaller than a preset current value;
and the conduction module is used for conducting the first diode valve and the second diode valve in the offshore converter station to finish the starting of the offshore wind power direct current transmission system.
In a third aspect, the present application also provides a computer device, including a memory and a processor, where the memory and the processor are communicatively connected to each other, and the memory stores computer instructions, and the processor executes the computer instructions, so as to execute the steps of the method for starting the offshore wind power dc transmission system with the dc bypass switch according to the first aspect or any embodiment of the first aspect.
In a fourth aspect, the present application also provides a computer readable storage medium, on which a computer program is stored, which when executed by a processor, implements the steps of the method for starting an offshore wind power direct current transmission system comprising a direct current bypass switch according to the first aspect or any implementation manner of the first aspect.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings that are needed in the description of the embodiments or the prior art will be briefly described, and it is obvious that the drawings in the description below are some embodiments of the present application, and other drawings can be obtained according to the drawings without inventive effort for a person skilled in the art.
FIG. 1 is a flowchart of a method for starting an offshore wind turbine DC power transmission system with a DC bypass switch in accordance with an exemplary embodiment;
FIG. 2 is a circuit diagram of an offshore wind turbine DC power transmission system with a DC bypass switch in accordance with an exemplary embodiment;
FIG. 3 is a schematic diagram of a starting device of an offshore wind power DC transmission system with a DC bypass switch according to an exemplary embodiment;
fig. 4 is a schematic diagram of a hardware structure of a computer device according to an exemplary embodiment.
Detailed Description
The following description of the embodiments of the present application will be made apparent and fully in view of the accompanying drawings, in which some, but not all embodiments of the application are shown. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.
In addition, the technical features of the different embodiments of the present application described below may be combined with each other as long as they do not collide with each other.
The application provides a starting method and device for an offshore wind power direct current transmission system with a direct current bypass switch, which are used for solving the problem that the starting method is not suitable for the offshore wind power direct current transmission system with the direct current bypass switch in the related art.
Fig. 1 is a flowchart of a method for starting an offshore wind power direct current transmission system with a direct current bypass switch according to an exemplary embodiment. The method is applied to an offshore wind power direct current transmission system with a direct current bypass switch, and fig. 2 is a circuit diagram of the system. The system comprises a land converter station 1, an offshore converter station 2, an offshore wind farm 3 and an offshore alternating current bus 4; the offshore converter station 2 comprises an offshore auxiliary soft direct converter valve 21, a first diode valve 22 and a second diode valve 23 connected in series with the offshore auxiliary soft direct converter valve 21; the offshore auxiliary soft direct current converter valve 21 and the first diode valve 22 are respectively connected with one end of the land-based converter station 1, and a first bypass switch 24 is connected between the offshore auxiliary soft direct current converter valve 21 and one end of the land-based converter station 1; the offshore auxiliary soft direct current converter valve 21 and the second diode valve 23 are respectively connected with the other end of the land-based converter station 1, and a second bypass switch 25 is connected between the offshore auxiliary soft direct current converter valve 21 and the other end of the land-based converter station 1; the first diode valve 22, the offshore auxiliary soft direct current converter valve 21 and the second diode valve 23 are respectively connected with the offshore alternating current bus 4; the offshore ac busbar 4 is connected to an offshore wind farm 3. As shown in fig. 1, the method includes the following steps S101 to S103.
Step S101: the control land-based converter station 1 charges the offshore auxiliary soft direct converter valve 21 in the offshore converter station 2 such that the offshore auxiliary soft direct converter valve 21 starts the offshore wind farm 3.
In an alternative embodiment, the offshore auxiliary soft direct converter valve 21 activates a partial number of fans in the offshore wind farm 3.
Step S102: the output power of the offshore wind farm 3 is controlled until the current value through the first bypass switch 24 and the second bypass switch 25 is smaller than a preset current value, and the first bypass switch 24 and the second bypass switch 25 are turned off.
In an alternative embodiment, the output power of the offshore wind farm 3 may be controlled by means of a controllable energy consumption of the started fans in the offshore wind farm 3.
In an alternative embodiment, the control of the output power of the offshore wind farm 3 may be achieved by implementing pitch limiting power control on started fans in the offshore wind farm 3.
In an alternative embodiment, the preset current value may be set according to actual needs, and is not particularly limited herein. Illustratively, 0 may be set. When the current value through the first bypass switch 24 and the second bypass switch 25 is smaller than the preset current value, the first bypass switch 24 and the second bypass switch 25 are turned off.
Step S103: the first diode valve 22 and the second diode valve 23 in the offshore converter station 2 are conducted to complete the starting of the offshore wind power direct current transmission system.
In view of the above, in order to achieve the light-weight of the offshore wind power dc transmission system and to provide the black start function, a dc bypass switch is provided in the offshore wind power dc transmission system, but the related starting method is not applicable to the system, by which the offshore auxiliary soft dc valve 21 is controlled to start the offshore wind farm 3, and then by controlling the output power of the offshore wind farm 3, when the current value through the first bypass switch 24 and the second bypass switch 25 is smaller than the preset current value, the first bypass switch 24 and the second bypass switch 25 are turned off, and the first diode valve 22 and the second diode valve 23 are controlled to be turned on, thereby achieving the black start function of the system.
In fig. 2, the system further comprises a land grid 5; the offshore converter station 2 further comprises a first transformer 26, a second transformer 27 and a third transformer 28; the land-based converter station 1 comprises a three-winding transformer 11 and a land-based soft direct current converter valve 12; the land soft direct current converter valve 12 consists of a plurality of half-bridge submodules; the three-winding transformer 11 comprises a grid-side high-voltage winding 111, a valve-side high-voltage winding 112 and a valve-side low-voltage winding 113, and the grid-side high-voltage winding 111 is connected with the land grid 5 through a first circuit breaker 13; the valve side high voltage winding 112 and the valve side low voltage winding 113 are respectively connected with A, B, C three phases of the land soft direct current converter valve 12 through the second circuit breaker 14 and the third circuit breaker 15; the land soft direct current converter valve 12 is connected with the offshore converter station 2; the first diode valve 22 is connected with the offshore alternating current bus 4 through a first transformer 26 and a sixth breaker 29 in sequence; the offshore auxiliary soft direct current converter valve 21 is connected with the offshore alternating current bus 4 through a fourth circuit breaker 210, a second transformer 27 and a fifth circuit breaker 211 in sequence; the second diode valve 23 is connected with the offshore alternating current bus 4 through a third transformer 28 and a seventh breaker 212 in sequence; the offshore ac busbar 4 is connected to an offshore wind farm 3.
In the above step S101, the offshore wind farm 3 is started by:
first, the first circuit breaker 13, the third circuit breaker 15, the first bypass switch 24 and the second bypass switch 25 are closed, so that the land grid 5 charges the land soft direct converter valve 12 in the land converter station 1 through the grid side high voltage winding 111 and the valve side low voltage winding 113 in the three winding transformer 11, while the land soft direct converter valve 12 charges the sea auxiliary soft direct converter valve 21 in the sea converter station 2 until the land soft direct converter valve 12 and the sea auxiliary soft direct converter valve 21 are completely charged.
In an alternative embodiment, the onshore soft direct current converter valve 12 charges the offshore auxiliary soft direct current converter valve 21 in the offshore converter station 2 uncontrollably via a dc sea cable.
Then, the land-based soft direct-current converter valve 12 and the marine auxiliary soft direct-current converter valve 21 are unlocked, and the direct-current voltage value of the land-based soft direct-current converter valve 12 is set to a preset direct-current voltage value.
In an alternative embodiment, the predetermined dc voltage value is substantially less than the nominal dc voltage value.
Finally, the fourth, fifth, sixth and seventh circuit breakers 210, 211, 29, 212 are closed, and the offshore auxiliary soft dc converter valve 21 is controlled to bring the voltage value of the offshore ac busbar 4 to a preset offshore ac busbar voltage, thereby starting a preset number of fans in the offshore wind farm 3.
In an alternative embodiment, the control offshore auxiliary soft direct current converter valve 21 outputs a preset offshore alternating current bus voltage in a zero-rise boosting mode, so that excitation surge current is prevented from being generated by a transformer connected with the first diode valve 22 and the second diode valve 23.
In an example, in the above step S102, the output power of the offshore wind farm 3 is controlled by:
the controllable energy consumption mode is adopted for the offshore wind farm 3 to control the active power output by a preset number of fans to the offshore auxiliary soft direct current converter valve 21, and the first bypass switch 24 and the second bypass switch 25 are disconnected until the current value passing through the first bypass switch 24 and the second bypass switch 25 is smaller than the preset current value.
In an example, in the above step S102, the output power of the offshore wind farm 3 may also be controlled by:
the pitch limiting power control is performed on a preset number of fans until the current value passing through the first bypass switch 24 and the second bypass switch 25 is smaller than a preset current value, and the first bypass switch 24 and the second bypass switch 25 are turned off.
By the embodiment of the application, the direct current bypass switch can be turned off at zero current, and the investment cost of the direct current switch is reduced.
At this time, after the power injected into the offshore wind farm 3 into the offshore converter station 2 removes the load of the offshore converter station 2, the transformer and other losses, the offshore converter station 2 and the offshore auxiliary soft direct current converter valve 21 can maintain the power balance for a certain time, and the time is enough to maintain the completion of the subsequent switching operation. If the offshore wind farm 3 adopts a controllable energy consumption mode to realize accurate control of output power, the power balance of the offshore converter station 2 and the offshore auxiliary soft direct current converter valve 21 can be maintained for a long time.
As shown in fig. 2, a first isolating switch 213 is connected between one end of the land-based soft direct current converter valve 12 and the first diode valve 22, and a second isolating switch 214 is connected between the other end of the land-based soft direct current converter valve 12 and the second diode valve 23.
In the above step S103, the start-up of the offshore wind power direct current transmission system is completed by turning on the first diode valve 22 and the second diode valve 23 in the offshore converter station 2 as follows:
first, the land-based soft dc converter valve 12 is controlled to increase the dc voltage value to the rated dc voltage value, and the third circuit breaker 15 is opened.
Second, when the dc voltage of the land-based soft dc converter valve 12 matches the voltage of the valve-side high voltage winding 112, the second circuit breaker 14 is closed.
In an alternative embodiment, the dc voltage of the land-based soft dc converter valve 12 is taken to control the voltage of the tracking valve side high voltage winding 112, and the second circuit breaker 14 is closed when the voltage amplitude and phase of the two match, i.e., (voltage of the valve side high voltage winding 112)/(0.5 times dc voltage) is less than 1.
Again, the offshore auxiliary soft dc converter valve 21 is controlled to reduce the dc voltage value of the offshore converter station 2 such that the dc voltage value of the offshore converter station 2 is smaller than the rated dc voltage value of the onshore soft dc converter valve 12, and the first isolation knife 213 and the second isolation knife 214 are closed.
Finally, the offshore auxiliary soft direct current converter valve 21 is controlled to increase the voltage value of the offshore alternating current bus 4 until the first diode valve 22 and the second diode valve 23 are conducted, and starting of the offshore wind power direct current transmission system is completed. At this time, smooth input of the first diode valve 22 and the second diode valve 23 is realized, and overvoltage and overcurrent resistant investment of the equipment is reduced.
By the starting method provided by the embodiment of the application, the offshore auxiliary soft direct current converter valve 21 can still maintain the offshore alternating current bus voltage for a short time under the condition that the direct current side is disconnected until the input of the diode valve is completed.
In an example, after the step S103, that is, after the first diode valve 22 and the second diode valve 23 in the offshore converter station 2 are turned on, the starting step of the offshore wind power direct current transmission system is completed, the method provided by the embodiment of the present application further includes:
and controlling the output power of the started fans in the offshore wind farm 3, enabling the started fans to enter a maximum power tracking mode, and starting other fans in the offshore wind farm 3.
In an alternative embodiment, the started fans are switched to the maximum power tracking mode after exiting the controllable energy consumption mode and the power limiting mode, and more fans are started at the same time, so that the whole system is switched to normal operation.
Based on the same inventive concept, the embodiment of the application also provides a starting device of the offshore wind power direct current transmission system with the direct current bypass switch, which is applied to the offshore wind power direct current transmission system with the direct current bypass switch, wherein the system comprises an onshore converter station, an offshore wind farm and an offshore alternating current bus; the offshore converter station comprises an offshore auxiliary soft direct current converter valve, a first diode valve and a second diode valve which are connected in series with the offshore auxiliary soft direct current converter valve; the offshore auxiliary soft direct current converter valve and the first diode valve are respectively connected with one end of the land-based converter station, and a first bypass switch is connected between the offshore auxiliary soft direct current converter valve and one end of the land-based converter station; the offshore auxiliary soft direct current converter valve and the second diode valve are respectively connected with the other end of the land-based converter station, and a second bypass switch is connected between the offshore auxiliary soft direct current converter valve and the other end of the land-based converter station; the first diode valve, the offshore auxiliary soft direct current converter valve and the second diode valve are respectively connected with an offshore alternating current bus; the offshore alternating current bus is connected with an offshore wind farm.
The device is shown in fig. 3, and comprises:
a first control module 301, configured to control the land-based converter station to charge an offshore auxiliary soft direct converter valve in the offshore converter station, so that the offshore auxiliary soft direct converter valve starts an offshore wind farm; the details are described in step S101 in the above embodiments, and are not described herein.
The second control module 302 is configured to control output power of the offshore wind farm, and disconnect the first bypass switch and the second bypass switch until a current value passing through the first bypass switch and the second bypass switch is smaller than a preset current value; the details refer to the description of step S102 in the above embodiment, and are not repeated here.
And the conduction module 303 is used for conducting the first diode valve and the second diode valve in the offshore converter station to finish starting the offshore wind power direct current transmission system. The details are described in step S103 in the above embodiments, and are not described herein.
In an example, the system further comprises a land grid; the offshore converter station further comprises a first transformer, a second transformer and a third transformer; the land-based converter station comprises a three-winding transformer and a land-based flexible direct current converter valve; the three-winding transformer comprises a network side high-voltage winding, a valve side high-voltage winding and a valve side low-voltage winding, wherein the network side high-voltage winding is connected with a land power grid through a first circuit breaker; the valve side high-voltage winding and the valve side low-voltage winding are connected with the land soft direct current converter valve through a second circuit breaker and a third circuit breaker respectively; the land flexible direct current converter valve is connected with the offshore converter station; the first diode valve is connected with an offshore alternating current bus through a first transformer and a sixth breaker in sequence; the offshore auxiliary soft direct current converter valve is connected with an offshore alternating current bus through a fourth circuit breaker, a second transformer and a fifth circuit breaker in sequence; the second diode valve is connected with the offshore alternating current bus through a third transformer and a seventh breaker in sequence. The first control module 301 includes:
the first control submodule is used for closing the first circuit breaker, the third circuit breaker, the first bypass switch and the second bypass switch, so that the land power grid charges a land soft direct current valve in a land converter station through a network side high-voltage winding and a valve side low-voltage winding in the three-winding transformer, and meanwhile the land soft direct current valve charges a sea auxiliary soft direct current valve in the sea converter station until the land soft direct current valve and the sea auxiliary soft direct current valve are charged; the details are described in the above embodiments, and are not repeated here.
The unlocking submodule is used for unlocking the land soft direct current converter valve and the marine auxiliary soft direct current converter valve and setting the direct current voltage value of the land soft direct current converter valve to be a preset direct current voltage value; the details are described in the above embodiments, and are not repeated here.
The second control submodule is used for closing the fourth circuit breaker, the fifth circuit breaker, the sixth circuit breaker and the seventh circuit breaker, controlling the offshore auxiliary soft direct current converter valve to enable the voltage value of the offshore alternating current bus to reach the preset offshore alternating current bus voltage, and further starting a preset number of fans in the offshore wind power plant. The details are described in the above embodiments, and are not repeated here.
In an alternative embodiment, the second control submodule includes:
and the control unit is used for controlling the offshore auxiliary soft direct current converter valve to output preset offshore alternating current bus voltage in a zero-starting boosting mode. The details are described in the above embodiments, and are not repeated here.
In an example, the second control module 302 includes:
and the third control submodule is used for adopting a controllable energy consumption mode for the offshore wind farm so as to control the active power output by a preset number of fans to the offshore auxiliary soft direct current conversion valve, and the first bypass switch and the second bypass switch are disconnected until the current value passing through the first bypass switch and the second bypass switch is smaller than a preset current value. The details are described in the above embodiments, and are not repeated here.
In an example, the second control module 302 includes:
and the fourth control submodule is used for implementing variable pitch power limiting control on a preset number of fans, and switching off the first bypass switch and the second bypass switch until the current value passing through the first bypass switch and the second bypass switch is smaller than a preset current value. The details are described in the above embodiments, and are not repeated here.
In an example, a first isolation knife switch is connected between one end of the land-based soft direct current converter valve and the first diode valve, and a second isolation knife switch is connected between the other end of the land-based soft direct current converter valve and the second diode valve. The turn-on module 303 includes:
the fifth control submodule is used for controlling the land soft direct current converter valve to increase the direct current voltage value to the rated direct current voltage value and disconnecting the third circuit breaker; the details are described in the above embodiments, and are not repeated here.
The closing submodule is used for closing the second circuit breaker when the direct-current voltage of the land soft direct-current converter valve is matched with the voltage of the valve side high-voltage winding; the details are described in the above embodiments, and are not repeated here.
The sixth control submodule is used for controlling the offshore auxiliary soft direct current converter valve to reduce the direct current voltage value of the offshore converter station, so that the direct current voltage value of the offshore converter station is smaller than the rated direct current voltage value of the onshore soft direct current converter valve, and the first isolation disconnecting link and the second isolation disconnecting link are closed; the details are described in the above embodiments, and are not repeated here.
And the conduction sub-module is used for controlling the offshore auxiliary soft direct current converter valve to increase the voltage value of the offshore alternating current bus until the first diode valve and the second diode valve are conducted, so that the starting of the offshore wind power direct current transmission system is completed. The details are described in the above embodiments, and are not repeated here.
In an example, the apparatus further comprises:
and the third control module is used for controlling the output power of the started fans in the offshore wind farm, enabling the started fans to enter a maximum power tracking mode and starting other fans in the offshore wind farm. The details are described in the above embodiments, and are not repeated here.
The specific limitation of the device and the beneficial effects can be seen from the limitation of the starting method of the offshore wind power direct current transmission system with the direct current bypass switch, and the description is omitted here. The various modules described above may be implemented in whole or in part by software, hardware, or a combination thereof. The above modules may be embedded in hardware or may be independent of a processor in the computer device, or may be stored in software in a memory in the computer device, so that the processor may call and execute operations corresponding to the above modules.
Fig. 4 is a schematic diagram of a hardware structure of a computer device according to an exemplary embodiment. As shown in fig. 4, the device includes one or more processors 410 and a memory 420, the memory 420 including persistent memory, volatile memory and a hard disk, one processor 410 being illustrated in fig. 4. The apparatus may further include: an input device 430 and an output device 440.
The processor 410, memory 420, input device 430, and output device 440 may be connected by a bus or other means, for example in fig. 4.
The processor 410 may be a central processing unit (Central Processing Unit, CPU). The processor 410 may also be a chip such as other general purpose processors, digital signal processors (Digital Signal Processor, DSP), application specific integrated circuits (Application Specific Integrated Circuit, ASIC), field programmable gate arrays (Field-Programmable Gate Array, FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, or a combination thereof. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like.
The memory 420 is used as a non-transitory computer readable storage medium, and includes a persistent memory, a volatile memory, and a hard disk, and may be used to store a non-transitory software program, a non-transitory computer executable program, and a module, such as a program instruction/module corresponding to a method for starting an offshore wind power direct current transmission system including a direct current bypass switch in an embodiment of the present application. The processor 410 executes various functional applications and data processing of the server by running non-transitory software programs, instructions and modules stored in the memory 420, that is, implements any of the above-described startup methods of the offshore wind power dc transmission system including the dc bypass switch.
Memory 420 may include a storage program area that may store an operating system, at least one application program required for functionality, and a storage data area; the storage data area may store data, etc., as needed, used as desired. In addition, memory 420 may include high-speed random access memory, and may also include non-transitory memory, such as at least one magnetic disk storage device, flash memory device, or other non-transitory solid state storage device. In some embodiments, memory 420 may optionally include memory located remotely from processor 410, which may be connected to the data processing apparatus via a network. Examples of such networks include, but are not limited to, the internet, intranets, local area networks, mobile communication networks, and combinations thereof.
The input device 430 may receive input numeric or character information and generate signal inputs related to user settings and function control. The output 440 may include a display device such as a display screen.
One or more modules are stored in memory 420 that, when executed by one or more processors 410, perform the method illustrated in fig. 1.
The product can execute the method provided by the embodiment of the application, and has the corresponding functional modules and beneficial effects of the execution method. Technical details which are not described in detail in the present embodiment can be found in the embodiment shown in fig. 1.
The embodiment of the application also provides a non-transitory computer storage medium, wherein the computer storage medium stores computer executable instructions, and the computer executable instructions can execute the starting method in any of the method embodiments. The storage medium may be a magnetic Disk, an optical Disk, a Read-Only Memory (ROM), a random access Memory (Random Access Memory, RAM), a Flash Memory (Flash Memory), a Hard Disk (HDD), or a Solid State Drive (SSD); the storage medium may also comprise a combination of memories of the kind described above.
It should be noted that in this document, relational terms such as "first" and "second" and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises an element.
The foregoing is merely exemplary of embodiments of the present application to enable those skilled in the art to understand or practice the application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (10)
1. The starting method of the offshore wind power direct current transmission system with the direct current bypass switch is characterized by being applied to the offshore wind power direct current transmission system with the direct current bypass switch, wherein the system comprises a land current conversion station, an offshore wind farm and an offshore alternating current bus; the offshore converter station comprises an offshore auxiliary soft direct current converter valve, a first diode valve and a second diode valve which are connected in series with the offshore auxiliary soft direct current converter valve; the offshore auxiliary soft direct current converter valve and the first diode valve are respectively connected with one end of the land-based converter station, and a first bypass switch is connected between the offshore auxiliary soft direct current converter valve and one end of the land-based converter station; the marine auxiliary soft direct current converter valve and the second diode valve are respectively connected with the other end of the land-based converter station, and a second bypass switch is connected between the marine auxiliary soft direct current converter valve and the other end of the land-based converter station; the first diode valve, the offshore auxiliary soft direct current converter valve and the second diode valve are respectively connected with the offshore alternating current bus; the offshore alternating current bus is connected with the offshore wind farm;
the method comprises the following steps:
controlling a land converter station to charge an offshore auxiliary soft direct current converter valve in an offshore converter station so that the offshore auxiliary soft direct current converter valve starts an offshore wind farm;
controlling the output power of the offshore wind farm until the current value passing through the first bypass switch and the second bypass switch is smaller than a preset current value, and switching off the first bypass switch and the second bypass switch;
and (5) switching on the first diode valve and the second diode valve in the offshore converter station to finish the starting of the offshore wind power direct current transmission system.
2. The method of claim 1, wherein the system further comprises a land grid; the offshore converter station further comprises a first transformer, a second transformer and a third transformer; the land-based converter station comprises a three-winding transformer and a land-based soft direct current converter valve; the three-winding transformer comprises a network side high-voltage winding, a valve side high-voltage winding and a valve side low-voltage winding, and the network side high-voltage winding is connected with the land power grid through a first circuit breaker; the valve side high-voltage winding and the valve side low-voltage winding are connected with the land flexible direct current converter valve through a second circuit breaker and a third circuit breaker respectively; the land flexible direct current converter valve is connected with the offshore converter station; the first diode valve is connected with the offshore alternating current bus through the first transformer and the sixth breaker in sequence; the offshore auxiliary soft direct current converter valve is connected with the offshore alternating current bus through a fourth circuit breaker, the second transformer and a fifth circuit breaker in sequence; the second diode valve is connected with the offshore alternating current bus through the third transformer and the seventh breaker in sequence;
the control land-based converter station charges an offshore auxiliary soft direct converter valve in an offshore converter station to enable the offshore auxiliary soft direct converter valve to start an offshore wind farm, comprising:
closing a first circuit breaker, a third circuit breaker, a first bypass switch and a second bypass switch, so that a land power grid charges a land soft direct current converter valve in a land converter station through a network side high-voltage winding and a valve side low-voltage winding in a three-winding transformer, and simultaneously the land soft direct current converter valve charges a sea auxiliary soft direct current converter valve in a sea converter station until the land soft direct current converter valve and the sea auxiliary soft direct current converter valve are charged;
unlocking the land soft direct current converter valve and the marine auxiliary soft direct current converter valve, and setting the direct current voltage value of the land soft direct current converter valve to be a preset direct current voltage value;
and closing a fourth circuit breaker, a fifth circuit breaker, a sixth circuit breaker and a seventh circuit breaker, and controlling the offshore auxiliary soft direct current converter valve to enable the voltage value of the offshore alternating current bus to reach the preset offshore alternating current bus voltage, so as to start a preset number of fans in the offshore wind power plant.
3. The method of claim 2, wherein controlling the output power of the offshore wind farm until the current value through the first bypass switch and the second bypass switch is less than a preset current value, comprises:
and adopting a controllable energy consumption mode for the offshore wind farm to control the active power output by a preset number of fans to the offshore auxiliary soft direct current converter valve, and switching off the first bypass switch and the second bypass switch until the current value passing through the first bypass switch and the second bypass switch is smaller than a preset current value.
4. The method of claim 2, wherein controlling the output power of the offshore wind farm until the current value through the first bypass switch and the second bypass switch is less than a preset current value, comprises:
and implementing variable pitch power limiting control on a preset number of fans until the current value passing through the first bypass switch and the second bypass switch is smaller than a preset current value, and switching off the first bypass switch and the second bypass switch.
5. The method of claim 2, wherein a first isolation knife gate is connected between one end of the land-based soft direct-current converter valve and the first diode valve, and a second isolation knife gate is connected between the other end of the land-based soft direct-current converter valve and the second diode valve;
the method for starting the offshore wind power direct current transmission system comprises the steps of:
controlling the land soft direct current converter valve to increase the direct current voltage value to a rated direct current voltage value, and disconnecting the third circuit breaker;
closing a second circuit breaker when the direct current voltage of the land soft direct current converter valve is matched with the voltage of the valve side high voltage winding;
controlling an offshore auxiliary soft direct current converter valve to reduce the direct current voltage value of the offshore converter station, enabling the direct current voltage value of the offshore converter station to be smaller than the rated direct current voltage value of the onshore soft direct current converter valve, and closing a first isolation disconnecting link and a second isolation disconnecting link;
and controlling the offshore auxiliary soft direct current converter valve to increase the voltage value of the offshore alternating current bus until the first diode valve and the second diode valve are conducted, and starting the offshore wind power direct current transmission system.
6. The method of claim 2, wherein controlling the marine auxiliary soft dc converter valve to bring the voltage value of the marine ac bus to a preset marine ac bus voltage comprises:
and controlling the offshore auxiliary soft direct current converter valve to output the preset offshore alternating current bus voltage in a zero-starting boosting mode.
7. The method of claim 2, wherein after completing the step of starting the offshore wind power direct current transmission system by switching on the first diode valve and the second diode valve in the offshore converter station, the method further comprises:
and controlling the output power of the started fans in the offshore wind farm, enabling the started fans to enter a maximum power tracking mode, and starting other fans in the offshore wind farm.
8. The starting device of the offshore wind power direct current transmission system with the direct current bypass switch is characterized by being applied to the offshore wind power direct current transmission system with the direct current bypass switch, wherein the system comprises a land current conversion station, an offshore wind farm and an offshore alternating current bus; the offshore converter station comprises an offshore auxiliary soft direct current converter valve, a first diode valve and a second diode valve which are connected in series with the offshore auxiliary soft direct current converter valve; the offshore auxiliary soft direct current converter valve and the first diode valve are respectively connected with one end of the land-based converter station, and a first bypass switch is connected between the offshore auxiliary soft direct current converter valve and one end of the land-based converter station; the marine auxiliary soft direct current converter valve and the second diode valve are respectively connected with the other end of the land-based converter station, and a second bypass switch is connected between the marine auxiliary soft direct current converter valve and the other end of the land-based converter station; the first diode valve, the offshore auxiliary soft direct current converter valve and the second diode valve are respectively connected with the offshore alternating current bus; the offshore alternating current bus is connected with the offshore wind farm;
the device comprises:
the offshore auxiliary soft direct current converter valve is used for starting an offshore wind power plant;
the second control module is used for controlling the output power of the offshore wind farm, and switching off the first bypass switch and the second bypass switch until the current value passing through the first bypass switch and the second bypass switch is smaller than a preset current value;
and the conduction module is used for conducting the first diode valve and the second diode valve in the offshore converter station to finish the starting of the offshore wind power direct current transmission system.
9. A computer device comprising a memory and a processor, said memory and said processor being communicatively coupled to each other, said memory having stored therein computer instructions, said processor executing said computer instructions to perform the steps of the method for starting an offshore wind power dc transmission system comprising a dc bypass switch according to any one of claims 1-7.
10. A computer readable storage medium, on which a computer program is stored, characterized in that the computer program, when being executed by a processor, carries out the steps of the method for starting an offshore wind power direct current transmission system comprising a direct current bypass switch according to any one of claims 1-7.
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| CN202311002633.1A CN116722575B (en) | 2023-08-10 | 2023-08-10 | Method and device for starting offshore wind power direct-current transmission system with direct-current bypass switch |
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