Offshore wind farm power transmission system startup method and apparatus, device, medium, and product

Abstract

The present application relates to an offshore wind farm power transmission system startup method and apparatus, a device, a medium, and a product. The method comprises: acquiring a startup voltage generated by a generator provided in an offshore rectifier station, and according to the startup voltage, starting up a first grid-forming wind turbine in an offshore wind farm; acquiring a voltage generated by the first grid-forming wind turbine, and according to the voltage, starting grid-forming wind turbines to be started; and acquiring voltages generated by all of the started grid-forming wind turbines, obtaining a power transmission voltage, and transmitting the power transmission voltage to an onshore converter station by means of the offshore rectifier station. In the above method used in the present application, the first grid-forming wind turbine is started up by means of the generator in the offshore rectifier station, and then electric energy generated by the first grid-forming wind turbine is utilized to start up the remaining grid-forming wind turbines to be started in the offshore wind farm, so that the problem of wind turbines in an offshore wind farm being difficult to start up when an offshore rectifier station or an onshore converter station fails is solved, thereby improving the stability and reliability of the offshore wind farm power transmission system.

Description

Offshore wind farm transmission system startup methods, devices, equipment, media and products Technical Field

[0001] The present application relates to the technical field of offshore wind power, and in particular to a method, device, equipment, medium and product for starting an offshore wind farm transmission system. Background Art

[0002] As offshore wind farm capacity and transmission distances increase, HVDC Flexible has become a mainstream solution for large-capacity offshore wind farms in deep waters. With its excellent stability, strong transmission capacity, and low transmission losses, HVDC Flexible can effectively promote the development and utilization of offshore wind farms.

[0003] In the existing technology, the offshore wind farm transmission system includes an onshore converter station, an offshore converter station and an offshore wind farm. The offshore wind farm includes several wind turbines. When the transmission system is in operation, the onshore converter station first generates a DC voltage to start the offshore converter station. The offshore converter station then generates AC power with a constant frequency and constant voltage, so that the wind turbines in the offshore wind farm drive the several wind turbines to start one by one and merge into the transmission system.

[0004] However, wind turbines in the prior art mainly rely on onshore converter stations for power supply. If an onshore converter station or an offshore converter station fails, the wind turbines in the offshore wind farm will be difficult to start, resulting in low reliability of the offshore wind farm power transmission system in the prior art.

[0005] Summary of the Invention

[0006] Based on this, it is necessary to provide a highly reliable offshore wind farm transmission system startup method, device, equipment, medium and product to address the above technical problems.

[0007] In a first aspect, the present application provides a method for starting an offshore wind farm transmission system. The method comprises:

[0008] Obtaining the starting voltage generated by the generator installed in the offshore rectifier station, and starting the first grid-type wind turbine in the offshore wind farm according to the starting voltage;

[0009] Obtain the voltage generated by the first grid-type wind turbine, and start the grid-type wind turbine to be started according to the voltage;

[0010] The voltage generated by all started grid-connected wind turbines is obtained to obtain the transmission voltage, and the transmission voltage is transmitted to the onshore converter station through the offshore rectifier station.

[0011] In one embodiment, starting a first grid-type wind turbine in an offshore wind farm according to a starting voltage includes:

[0012] The starting voltage is transmitted to the energy storage device of the first grid-type wind turbine. If the amount of electricity stored in the energy storage device reaches the electricity threshold for starting the first grid-type wind turbine, the first grid-type wind turbine is started.

[0013] In one embodiment, obtaining the voltage generated by the first grid-type wind turbine and starting the grid-type wind turbine to be started according to the voltage includes:

[0014] Obtaining voltage, and starting at least one grid-type wind turbine to be started according to the voltage;

[0015] The voltage generated by the started grid-type wind turbine is repeatedly obtained, and the remaining grid-type wind turbines to be started are started according to the voltage generated by the started grid-type wind turbine, until all the grid-type wind turbines are started.

[0016] In one embodiment, the method further comprises:

[0017] The starting voltage is less than the rated voltage of the diode rectifier tube arranged in the offshore rectifier station when it is turned on.

[0018] In one embodiment, the grid-type wind turbine further includes a grid-side converter for regulating the transmission voltage, and before transmitting the transmission voltage to the onshore converter station through the offshore rectifier station, further includes:

[0019] Determine whether the transmission voltage is less than the rated voltage. If the transmission voltage is less than the rated voltage, control the grid-side converter corresponding to the transmission voltage to increase the transmission voltage to the rated voltage at a preset rate.

[0020] In one embodiment, controlling a grid-side converter corresponding to a transmission voltage to increase the transmission voltage to a rated voltage at a preset rate includes:

[0021] During the preset compensation time period, it is determined whether the grid-side converter corresponding to the transmission voltage can increase the transmission voltage to the rated voltage at a preset rate. If the grid-side converter cannot increase the transmission voltage to the rated voltage at the preset rate, the energy storage device of the grid-type wind turbine corresponding to the grid-side converter is started to increase the transmission voltage to the rated voltage at the preset rate.

[0022] In a second aspect, the present application also provides a device for starting an offshore wind farm transmission system. The device comprises:

[0023] A first starting module is used to obtain a starting voltage generated by a generator provided in an offshore rectifier station, and start the first grid-type wind turbine in the offshore wind farm according to the starting voltage;

[0024] The second starting module is used to obtain the voltage generated by the first grid-type wind turbine and start the grid-type wind turbine to be started according to the voltage;

[0025] The voltage transmission module is used to obtain the voltage generated by all started grid-type wind turbines, obtain the transmission voltage, and transmit the transmission voltage to the onshore converter station through the offshore rectifier station.

[0026] In a third aspect, the present application further provides a computer device. The computer device includes a memory and a processor. The memory stores a computer program. When the processor executes the computer program, the following steps are performed:

[0027] Obtaining the starting voltage generated by the generator installed in the offshore rectifier station, and starting the first grid-type wind turbine in the offshore wind farm according to the starting voltage;

[0028] Obtain the voltage generated by the first grid-type wind turbine, and start the grid-type wind turbine to be started according to the voltage;

[0029] The voltage generated by all started grid-connected wind turbines is obtained to obtain the transmission voltage, and the transmission voltage is transmitted to the onshore converter station through the offshore rectifier station.

[0030] In a fourth aspect, the present application further provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the following steps:

[0031] Obtaining the starting voltage generated by the generator installed in the offshore rectifier station, and starting the first grid-type wind turbine in the offshore wind farm according to the starting voltage;

[0032] Obtain the voltage generated by the first grid-type wind turbine, and start the grid-type wind turbine to be started according to the voltage;

[0033] The voltage generated by all started grid-connected wind turbines is obtained to obtain the transmission voltage, and the transmission voltage is transmitted to the onshore converter station through the offshore rectifier station.

[0034] In a fifth aspect, the present application further provides a computer program product. The computer program product includes a computer program that, when executed by a processor, implements the following steps:

[0035] Obtaining the starting voltage generated by the generator installed in the offshore rectifier station, and starting the first grid-type wind turbine in the offshore wind farm according to the starting voltage;

[0036] Obtain the voltage generated by the first grid-type wind turbine, and start the grid-type wind turbine to be started according to the voltage;

[0037] The voltage generated by all started grid-connected wind turbines is obtained to obtain the transmission voltage, and the transmission voltage is transmitted to the onshore converter station through the offshore rectifier station.

[0038] The above-mentioned offshore wind farm transmission system startup method, device, equipment, medium and product obtain the starting voltage generated by the generator set in the offshore rectifier station, and start the first grid-type wind turbine in the offshore wind farm according to the starting voltage; obtain the voltage generated by the first grid-type wind turbine, and start the grid-type wind turbine to be started according to the voltage; obtain the voltage generated by all started grid-type wind turbines to obtain the transmission voltage, and transmit the transmission voltage to the onshore converter station through the offshore rectifier station. The present application adopts the above-mentioned method to start the first grid-type wind turbine through the generator in the offshore rectifier station, and then convert the wind energy into electrical energy through the first grid-type wind turbine, so as to use the electrical energy generated by the first grid-type wind turbine to start the remaining grid-type wind turbines to be started in the offshore wind farm, thereby solving the problem that the wind turbines in the offshore wind farm are difficult to start when a fault occurs in the offshore rectifier station or the onshore converter station, thereby improving the stability and reliability of the offshore wind farm transmission system. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] FIG1 is a diagram illustrating an application environment of a method for starting an offshore wind farm power transmission system according to an embodiment;

[0040] FIG2 is a flow chart of a method for starting an offshore wind farm power transmission system according to one embodiment;

[0041] FIG3 is a flow chart of a method for starting a grid-type fan in one embodiment;

[0042] FIG4 is a flow chart of regulating transmission voltage in one embodiment;

[0043] FIG5 is a structural block diagram of a starting device for an offshore wind farm power transmission system according to one embodiment;

[0044] FIG6 is a diagram showing the internal structure of a computer device according to one embodiment;

[0045] FIG7 is a diagram showing the internal structure of a computer device in another embodiment. DETAILED DESCRIPTION

[0046] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0047] The offshore wind farm transmission system startup method provided in the embodiment of the present application can be applied to the application environment shown in Figure 1. In the figure, the offshore wind farm transmission system includes an onshore converter station 110, an offshore rectifier station 120, and an offshore wind farm 130, wherein the offshore rectifier station 120 includes a generator and a diode rectifier tube. The generator in this embodiment can be a high-power diesel generator, and the diode rectifier tube can be a large-capacity diode rectifier tube. The offshore wind farm 130 includes a number of grid-type wind turbines installed on an offshore platform, and the grid-type wind turbines are operated in parallel. The onshore converter station 110, the offshore rectifier station 120, and the offshore wind farm 130 are sequentially connected by submarine cables, and the three can communicate with each other through the network or electrical signals. The offshore wind farm 130 generates alternating current (AC) by starting up a number of grid-type wind turbines, and transmits the AC to the offshore rectifier station 120 via submarine cables. The offshore rectifier station 120 converts the AC into DC to reduce power loss during transmission, and then transmits the DC to the onshore converter station 110 via submarine cables. The onshore converter station 110 then converts the DC into synchronous AC compatible with the land power grid, and finally transmits the synchronous AC to the land power grid via cables.

[0048] In one embodiment, as shown in FIG2 , the method is described by taking the application environment in FIG1 as an example. In this embodiment, the method includes the following steps:

[0049] Step 202: obtaining a starting voltage generated by a generator installed in an offshore rectifier station, and starting the first grid-type wind turbine in the offshore wind farm according to the starting voltage.

[0050] Among them, the offshore rectifier station is also called the offshore power grid. The offshore rectifier station can convert the AC power generated by the offshore wind farm into DC power in order to minimize the power loss generated during long-distance transmission. The first grid-type wind turbine can be determined based on the preset number of all the grid-type wind turbines in the offshore wind farm. For example, the grid-type wind turbine numbered 01 is the first grid-type wind turbine. It can also be determined based on the distance between the grid-type wind turbine and the generator. For example, the grid-type wind turbine closest to the generator is determined as the first grid-type wind turbine. The generator in the offshore rectifier station is used to provide power for the startup of the first grid-type wind turbine. The generator in the offshore rectifier station can be a high-power diesel generator.

[0051] For example, in the initial state, all grid-type wind turbines in the offshore wind farm are not started. When the generator is started, the starting voltage generated by the generator is obtained and transmitted to the first grid-type wind turbine to start the first grid-type wind turbine. In this embodiment, the generator in the offshore rectifier station only needs to provide the starting voltage for one grid-type wind turbine, not for all grid-type wind turbines in the offshore wind farm, which helps reduce the startup cost of the grid-type wind turbines.

[0052] Step 204 : obtaining the voltage generated by the first grid-type wind turbine, and starting the grid-type wind turbine to be started according to the voltage.

[0053] The grid-connected wind turbines to be started are the unstarted grid-connected wind turbines in the offshore wind farm, excluding the first grid-connected wind turbine. A grid-connected wind turbine includes an energy storage device, a grid-side converter, a machine-side converter, and a generator. The energy storage device is used to store excess electricity generated by the generator to provide power for restarting the wind turbine. The grid-side converter is used to convert the direct current (DC) output of the wind turbine into alternating current (AC) suitable for transmission to the onshore power grid. The grid-side converter can also regulate the voltage generated by the wind turbine to ensure smooth and stable power transmission from the offshore wind farm. The machine-side converter is used to convert the AC power generated by the generator into DC power, which is then converted to AC power by the power electronics in the wind turbine and then transmitted to the grid-side converter. The machine-side converter can also control the generator of the grid-connected wind turbine to charge the energy storage device. The machine-side converter can also control the generator's power generation efficiency.

[0054] For example, after the first grid-type wind turbine is started, the first grid-type wind turbine converts wind energy into electrical energy and transmits the electrical energy generated by the first grid-type wind turbine to the grid-type wind turbine to be started. When the electrical energy received by the grid-type wind turbine to be started reaches the power threshold required for its own startup, it starts automatically.

[0055] Step 206 , obtaining the voltage generated by all started grid-connected wind turbines to obtain the transmission voltage, and transmitting the transmission voltage to the onshore converter station through the offshore rectifier station.

[0056] Among them, the onshore converter station is the key equipment connecting the offshore wind farm and the land power grid. It is generally built on land near the offshore wind farm. Its main function is to convert the AC power output by the grid-type wind turbines in the offshore wind farm into the synchronous AC power required by the land power grid, and transmit it to the land power grid through cables.

[0057] For example, after all the grid-type wind turbines in the offshore wind farm are started, under the action of offshore wind, the grid-type wind turbines convert wind energy into electrical energy and generate transmission voltage, which is first transmitted to the offshore rectifier station through the submarine cable. The offshore rectifier station converts the transmission voltage into DC voltage, which is then transmitted to the onshore converter station through the submarine cable. After the onshore converter station converts the DC voltage into AC voltage, the AC voltage is integrated into the onshore power grid, thereby realizing power transmission from the offshore wind farm transmission system to the onshore power grid.

[0058] In the above-mentioned offshore wind farm transmission system startup method, the starting voltage generated by the generator installed in the offshore rectifier station is obtained, and the first grid-type wind turbine in the offshore wind farm is started according to the starting voltage; the voltage generated by the first grid-type wind turbine is obtained, and the grid-type wind turbines to be started are started according to the voltage; the voltage generated by all started grid-type wind turbines is obtained to obtain the transmission voltage, and the transmission voltage is transmitted to the onshore converter station through the offshore rectifier station. The method of this embodiment starts the first grid-type wind turbine by the generator in the offshore rectifier station, and then converts wind energy into electrical energy by the first grid-type wind turbine, so as to use the electrical energy generated by the first grid-type wind turbine to start the remaining grid-type wind turbines to be started in the offshore wind farm, thereby solving the problem that the wind turbines in the offshore wind farm are difficult to start when a fault occurs in the offshore rectifier station or the onshore converter station, thereby improving the stability and reliability of the offshore wind farm transmission system.

[0059] In one embodiment, starting the first grid-type wind turbine in an offshore wind farm according to the starting voltage includes: transmitting the starting voltage to the energy storage device of the first grid-type wind turbine, and starting the first grid-type wind turbine if the amount of electricity stored in the energy storage device reaches the electricity threshold for starting the first grid-type wind turbine.

[0060] The energy storage device of a grid-connected wind turbine is a device used to store electrical energy, and the energy storage device can be a battery. When the amount of energy stored in the energy storage device reaches the threshold required to start the first grid-connected wind turbine, the first grid-connected wind turbine automatically starts. The energy storage device not only provides the electricity required for grid-connected wind turbine startup, but also stores excess electricity generated by the grid-connected wind turbine when offshore wind speeds are high. The amount of energy storage required depends on the scale of the wind farm, the load on the grid, changes in transmission demand, and the stability and reliability of the transmission system. For some offshore wind farms, due to their small scale, small grid load fluctuations, and high transmission system stability, the use of energy storage devices is not essential. Conversely, for some offshore wind farms, especially those with small or unstable transmission system capacity, energy storage devices can balance the difference between wind power generation and consumption and offset fluctuations during unstable wind speeds, thereby achieving a stable transmission voltage output.

[0061] In this embodiment, the energy storage device facilitates the started grid-type wind turbines to start the grid-type wind turbines to be started, and the starting electric energy mainly comes from the wind energy received by the started grid-type wind turbines, which helps to improve the energy saving and environmental protection of the offshore wind farm transmission system.

[0062] In one embodiment, as shown in FIG3 , obtaining the voltage generated by the first grid-type wind turbine and starting the grid-type wind turbine to be started according to the voltage includes:

[0063] Step 302: Obtain voltage, and start at least one grid-type wind turbine to be started according to the voltage.

[0064] For example, when the first grid-type wind turbine is located at a location with a higher wind speed in an offshore wind farm, the voltage generated by the first grid-type wind turbine is larger. The voltage generated by the first grid-type wind turbine may be able to start at least one grid-type wind turbine to be started. The voltage generated by the first grid-type wind turbine is then transmitted to one or more grid-type wind turbines to be started according to the number of the grid-type wind turbine or the distance. For example, the voltage generated by the first grid-type wind turbine is transmitted to two grid-type wind turbines numbered 02 and 03 respectively.

[0065] Step 304 : repeatedly obtaining the voltage generated by the started meshed wind turbines, and starting the remaining meshed wind turbines to be started according to the voltage generated by the started meshed wind turbines, until all meshed wind turbines are started.

[0066] For example, after the starting voltage is output to the first grid-type wind turbine, the grid-side converter of the first grid-type wind turbine uses a constant DC voltage control method to charge its own energy storage device. When the power in the energy storage device of the first grid-type wind turbine reaches the power threshold required to start itself, the first grid-type wind turbine starts. During startup, the energy storage device of the first grid-type wind turbine uses a constant DC voltage control method, and the grid-side converter of the first grid-type wind turbine switches to a constant AC voltage method, and the constant AC voltage is equal to the starting voltage, and the frequency is 50HZ. At this time, the generator is turned off, the machine-side converter of the first grid-type wind turbine is started, and the MPPT (Maximum Power Point The maximum power point tracking (MPPT) control method is used to obtain the maximum output power of the generator of the first grid-type wind turbine in real time, and enable the generator of the first grid-type wind turbine to generate electricity according to the maximum output power, and then transmit the transmission voltage of the first grid-type wind turbine to the onshore converter station through the offshore rectifier station. At the same time, according to the size of the transmission voltage generated by the first grid-type wind turbine, part of the transmission voltage generated by the first grid-type wind turbine is transmitted to at least one grid-type wind turbine to be started. After the grid-type wind turbine to be started is started, the transmission voltage of the started grid-type wind turbine is sequentially transmitted to the onshore converter station in the manner that the transmission voltage generated by the first grid-type wind turbine is transmitted to the onshore converter station. At the same time, the started grid-type wind turbine starts the remaining grid-type wind turbines to be started in the manner that the first grid-type wind turbine starts the grid-type wind turbine to be started, until all the grid-type wind turbines in the offshore wind farm are started.

[0067] In this embodiment, at least one of the meshed fans to be started is first started by the voltage generated by the first meshed fan, and then the voltage generated by the started meshed fans is used to start the remaining meshed fans to be started in the same way as the first meshed fan starts the meshed fans to be started, thereby achieving the complete startup of all meshed fans. Except for the first meshed fan, the electric energy required for the startup of the remaining meshed fans comes from the wind energy received after the other meshed fans are started, which helps to improve the energy saving and environmental protection of the meshed fans when they are started.

[0068] In one embodiment, the method further includes: the starting voltage is less than the rated voltage of the diode rectifier tube disposed in the offshore rectifier station when it is turned on.

[0069] The diode rectifier is a high-capacity diode suitable for high current and high voltage. Its primary function is to convert the AC power output by the grid-type wind turbine into DC power for simultaneous conversion to DC power for transmission to the onshore power grid. Because the diode rectifier has unidirectional conductivity, the conduction condition for the diode rectifier is that the voltage difference between the positive and negative electrodes is greater than a preset voltage threshold. That is, the rated voltage of the diode rectifier when conducting is no less than the sum of the voltage of the diode's negative electrode and the voltage threshold. Once the diode rectifier is conducting, the voltage is diverted from the positive electrode to the negative electrode. In this embodiment, after the diode rectifier is conducting, the transmission voltage generated by the offshore wind farm is diverted from the offshore wind farm via the offshore rectifier station to the onshore converter station. Since the generator's starting voltage is primarily used to start the first grid-type wind turbine, to avoid the situation where the starting voltage is unable to continue starting the first grid-type wind turbine after conducting the diode, the starting voltage is set to a value lower than the rated voltage.

[0070] For example, the positive electrode of the diode rectifier in this embodiment is connected to the offshore wind farm through a cable, and the negative electrode of the diode rectifier is connected to the onshore converter station through a cable. Assuming that the preset voltage threshold is 2KV, when the voltage level corresponding to the onshore converter station is 500KV, the rated voltage of the diode rectifier when it is turned on is 502KV, that is, when the transmission voltage output by the offshore wind farm reaches 502KV, the diode rectifier is turned on, and the transmission voltage generated by the offshore wind farm will be transmitted to the onshore converter station through the offshore rectifier station.

[0071] In this embodiment, before starting the first mesh-type fan, the starting voltage is set to a value smaller than the rated voltage so that the starting voltage is fully transmitted to the first mesh-type fan, thereby avoiding the loss of the starting voltage and ensuring the smoothness of starting the first mesh-type fan.

[0072] In one embodiment, as shown in FIG4 , before the transmission voltage is transmitted to the onshore converter station through the offshore rectifier station, the method further includes:

[0073] Step 402, determine whether the transmission voltage is less than the rated voltage. If the transmission voltage is less than the rated voltage, execute step 404; otherwise, the system does not take any action.

[0074] For example, when the transmission voltage of an offshore wind farm is lower than the rated voltage, the electricity generated by the offshore wind farm is difficult to transmit to the onshore converter station through the diode rectifier, which may easily lead to reduced stability and reliability of the transmission system during power transmission.

[0075] Step 404 : Control the grid-side converter corresponding to the transmission voltage to increase the transmission voltage to the rated voltage at a preset rate.

[0076] Among them, from the above content, it can be seen that the grid-side converter of the grid-type wind turbine is used to convert the direct current output of the wind turbine into alternating current suitable for transmission to the onshore power grid. The grid-side converter can regulate the transmission voltage to ensure the stability and reliability of power transmission in the offshore wind farm.

[0077] For example, when the transmission voltage of an offshore wind farm is lower than the rated voltage, the output efficiency of the grid-type wind turbine is improved through the grid-side converter, thereby improving the output voltage of the grid-type wind turbine. When increasing the transmission voltage, in order to ensure the safe and stable operation of the grid-type wind turbine, it is necessary to increase it according to a preset rate. The preset rate can be set according to parameters such as the maximum output power, maximum output current and maximum voltage of the grid-type wind turbine. For example, the preset rate in this embodiment can be 100KV / min.

[0078] In this embodiment, the transmission voltage is compensated by the grid-side converter, so that the transmission voltage of the offshore wind farm can be smoothly output even when the transmission voltage is low, thereby improving the reliability and stability of the offshore wind farm transmission system.

[0079] In one embodiment, controlling the grid-side converter corresponding to the transmission voltage to increase the transmission voltage to the rated voltage at a preset rate includes: within a preset compensation time period, determining whether the grid-side converter corresponding to the transmission voltage can increase the transmission voltage to the rated voltage at a preset rate; if the grid-side converter cannot increase the transmission voltage to the rated voltage at the preset rate, starting the energy storage device of the grid-type wind turbine corresponding to the grid-side converter to increase the transmission voltage to the rated voltage at the preset rate.

[0080] Among them, the preset compensation time period is a preset voltage compensation time period. When the transmission voltage is lower than the rated voltage, in order to ensure the stability of the offshore wind farm transmission system during power transmission, the transmission voltage must be increased within the compensation time period. The preset compensation time period in this embodiment can be 2s, that is, the corresponding grid-side converter needs to increase the transmission voltage to the rated voltage at a preset rate within 2s.

[0081] For example, when the offshore wind speed is low, the grid-side converter may not be able to increase the transmission voltage by controlling the output efficiency of the grid-type wind turbine. In this case, the energy storage device can be controlled to release electric energy, so that the energy storage device cooperates with the grid-side converter to further compensate for the transmission voltage, thereby achieving the transmission voltage being increased to the rated voltage at a preset rate, thereby ensuring the smoothness and stability of the offshore wind farm transmission system during transmission.

[0082] In this embodiment, when the grid-side converter is unable to increase the transmission voltage within the preset compensation time period, the transmission voltage is further compensated by releasing the electric energy stored in the energy storage device, thereby ensuring the smoothness and stability of power transmission of the offshore wind farm transmission system.

[0083] In one embodiment, before obtaining the voltage generated by the first grid-forming wind turbine, the method further includes: starting an onshore converter station, and controlling the DC voltage between the onshore converter station and the offshore rectifier station to be constant.

[0084] The onshore converter station is started using a constant DC voltage control mode, which helps protect the capacitors and equipment in the transmission line between the onshore converter station and the offshore rectifier station, thereby ensuring the stable operation of the onshore power grid. The DC voltage between the onshore converter station and the offshore rectifier station is determined by the voltage level of the onshore power grid. For example, if the voltage level of the onshore power grid is 500kV, the DC voltage between the onshore converter station and the offshore rectifier station is determined to be 500kV.

[0085] For example, before starting the wind turbines in an offshore wind farm, the onshore converter station is started first and the DC voltage is controlled to be constant, which helps to alleviate the impact of the sudden surge in the offshore wind farm's transmission voltage on the onshore power grid, thereby ensuring the stability and safety of the offshore wind farm's transmission system during power transmission.

[0086] It should be understood that, although the various steps in the flowcharts involved in the various embodiments described above are displayed in sequence according to the instructions of the arrows, these steps are not necessarily executed in sequence in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order restriction on the execution of these steps, and these steps can be executed in other orders. Moreover, at least a portion of the steps in the flowcharts involved in the various embodiments described above can include multiple steps or multiple stages, and these steps or stages are not necessarily executed and completed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a portion of steps or stages in other steps.

[0087] Based on the same inventive concept, embodiments of the present application also provide an offshore wind farm transmission system startup device for implementing the offshore wind farm transmission system startup method described above. The solution provided by this device is similar to the solution described in the above-mentioned method. Therefore, the specific limitations of one or more embodiments of the offshore wind farm transmission system startup device provided below can be found in the above-mentioned limitations of the offshore wind farm transmission system startup method and will not be further elaborated here.

[0088] In one embodiment, as shown in FIG5 , a device for starting an offshore wind farm transmission system is provided, comprising: a first starting module 502 , a second starting module 504 , and a voltage transmission module 506 , wherein:

[0089] The first starting module 502 is used to obtain the starting voltage generated by the generator provided in the offshore rectifier station, and start the first grid-type wind turbine in the offshore wind farm according to the starting voltage;

[0090] The second starting module 504 is used to obtain the voltage generated by the first grid-type wind turbine and start the grid-type wind turbine to be started according to the voltage;

[0091] The voltage transmission module 506 is used to obtain the voltage generated by all the started grid-type wind turbines, obtain the transmission voltage, and transmit the transmission voltage to the onshore converter station through the offshore rectifier station.

[0092] In one embodiment, the first starting module 502 is further used to: transmit the starting voltage to the energy storage device of the first grid-type wind turbine, and start the first grid-type wind turbine if the power stored in the energy storage device reaches the power threshold for starting the first grid-type wind turbine.

[0093] In one embodiment, the second starting module 504 is also used to: obtain voltage, and start at least one meshed wind turbine to be started according to the voltage; repeatedly obtain the voltage generated by the started meshed wind turbine, and start the remaining meshed wind turbines to be started according to the voltage generated by the started meshed wind turbine, until all meshed wind turbines are started.

[0094] In one embodiment, the device is further configured to: enable a starting voltage lower than a rated voltage when a diode rectifier tube disposed in an offshore rectifier station is turned on.

[0095] In one embodiment, the voltage transmission module 506 is further used to determine whether the transmission voltage is less than the rated voltage. If the transmission voltage is less than the rated voltage, the grid-side converter corresponding to the transmission voltage is controlled to increase the transmission voltage to the rated voltage at a preset rate.

[0096] In one embodiment, the voltage transmission module 506 is further used to: determine whether the grid-side converter corresponding to the transmission voltage can increase the transmission voltage to the rated voltage at a preset rate within a preset compensation time period; if the grid-side converter cannot increase the transmission voltage to the rated voltage at the preset rate, start the energy storage device of the grid-type wind turbine corresponding to the grid-side converter to increase the transmission voltage to the rated voltage at the preset rate.

[0097] Each module in the aforementioned offshore wind farm transmission system startup device can be implemented in whole or in part through software, hardware, or a combination thereof. Each module can be embedded in or independent of a processor in a computer device in hardware form, or can be stored in a computer device memory in software form, so that the processor can call and execute the corresponding operations of each module.

[0098] In one embodiment, a computer device is provided, which may be a server, and its internal structure diagram may be as shown in FIG6 . The computer device includes a processor, a memory, and a network interface connected via a system bus. The processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program, and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the computer device is used to store relevant data of the land power grid, onshore converter station, offshore rectifier station, offshore wind farm, and grid-type wind turbine. The network interface of the computer device is used to communicate with an external terminal via a network connection. When the computer program is executed by the processor, a method for starting an offshore wind farm transmission system is implemented.

[0099] In one embodiment, a computer device is provided. The computer device may be a terminal, and its internal structure diagram may be as shown in FIG7 . The computer device includes a processor, memory, a communication interface, a display screen, and an input device connected via a system bus. The processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and computer program in the non-volatile storage medium. The communication interface of the computer device is used to communicate with an external terminal via wired or wireless communication. The wireless communication may be achieved via Wi-Fi, a mobile cellular network, NFC (near-field communication), or other technologies. When executed by the processor, the computer program implements a method for starting an offshore wind farm transmission system. The display screen of the computer device may be a liquid crystal display or an electronic ink display screen. The input device of the computer device may be a touch layer covering the display screen, or may be buttons, a trackball, or a touchpad provided on the computer device housing, or may be an external keyboard, touchpad, or mouse.

[0100] Those skilled in the art will understand that the structures shown in Figures 6 and 7 are merely block diagrams of partial structures related to the solution of the present application, and do not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than shown in the figures, or combine certain components, or have a different component arrangement.

[0101] In one embodiment, a computer device is provided, including a memory and a processor. The memory stores a computer program, and the processor implements the steps in the above method embodiments when executing the computer program.

[0102] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps in the above-mentioned method embodiments are implemented.

[0103] In one embodiment, a computer program product is provided, including a computer program, which implements the steps in the above method embodiments when executed by a processor.

[0104] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties.

[0105] Those skilled in the art will appreciate that all or part of the processes in the above-mentioned embodiment methods can be implemented by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, database or other media used in the embodiments provided in this application may include at least one of non-volatile and volatile memory. Non-volatile memory may include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory may include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The database involved in the various embodiments provided herein may include at least one of a relational database and a non-relational database. Non-relational databases may include, but are not limited to, distributed databases based on blockchains. The processor involved in the various embodiments provided herein may be, but are not limited to, a general-purpose processor, a central processing unit (CPU), a graphics processing unit (GPU), a digital signal processor (DSP), a programmable logic unit (PLC), a data processing logic unit based on quantum computing, and the like.

[0106] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0107] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present application shall be determined by the appended claims.

Claims

1. A method for starting an offshore wind farm transmission system, the method comprising: Obtaining a starting voltage generated by a generator disposed in an offshore rectifier station, and starting a first grid-type wind turbine in an offshore wind farm according to the starting voltage; Obtaining the voltage generated by the first grid-forming wind turbine, and starting the grid-forming wind turbine to be started according to the voltage; The voltage generated by all started grid-forming wind turbines is obtained to obtain a transmission voltage, and the transmission voltage is transmitted to an onshore converter station through the offshore rectifier station.

2. The method according to claim 1, characterized in that The method of starting the first grid-type wind turbine in the offshore wind farm according to the starting voltage comprises: The starting voltage is transmitted to the energy storage device of the first grid-type wind turbine. If the amount of electricity stored in the energy storage device reaches the electricity threshold for starting the first grid-type wind turbine, the first grid-type wind turbine is started.

3. The method according to claim 1, characterized in that The step of obtaining the voltage generated by the first grid-type wind turbine and starting the grid-type wind turbine to be started according to the voltage comprises: Obtaining the voltage, and starting at least one grid-type wind turbine to be started according to the voltage; The voltage generated by the started meshed fans is repeatedly obtained, and the remaining meshed fans to be started are started according to the voltage generated by the started meshed fans, until all the meshed fans are started.

4. The method according to claim 1, characterized in that: The method further comprises: The starting voltage is less than the rated voltage of the diode rectifier tube arranged in the offshore rectifier station when it is turned on.

5. The method according to claim 4, characterized in that The grid-type wind turbine further includes a grid-side converter for adjusting the transmission voltage, and before transmitting the transmission voltage to the onshore converter station through the offshore rectifier station, further includes: It is determined whether the transmission voltage is less than the rated voltage. If the transmission voltage is less than the rated voltage, the grid-side converter corresponding to the transmission voltage is controlled to increase the transmission voltage to the rated voltage at a preset rate.

6. The method according to claim 5, characterized in that The controlling the grid-side converter corresponding to the transmission voltage to increase the transmission voltage to the rated voltage at a preset rate includes: Within a preset compensation time period, determine whether the grid-side converter corresponding to the transmission voltage can increase the transmission voltage to the rated voltage at a preset rate; if the grid-side converter cannot increase the transmission voltage to the rated voltage at the preset rate, start the energy storage device of the grid-type wind turbine corresponding to the grid-side converter to increase the transmission voltage to the rated voltage at the preset rate.

7. A starting device for an offshore wind farm transmission system, characterized in that: The device comprises: A first starting module is used to obtain a starting voltage generated by a generator arranged in an offshore rectifier station, and start the first grid-type wind turbine in the offshore wind farm according to the starting voltage; A second starting module is used to obtain the voltage generated by the first grid-forming wind turbine and start the grid-forming wind turbine to be started according to the voltage; The voltage transmission module is used to obtain the voltage generated by all the started grid-forming wind turbines to obtain the transmission voltage, and transmit the transmission voltage to the onshore converter station through the offshore rectifier station.

8. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 6 are implemented.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.

10. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.

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