Offshore wind power collection line synchronous spare power automatic switching method and system

Abstract

The invention relates to a synchronous spare power automatic switching method and a synchronous spare power automatic switching system for an offshore wind power collection line, which are applied to an offshore converter station with more than or equal to 2 connecting transformers, and the method comprises the following steps of: setting a starting condition of spare power automatic switching control, and starting the spare power automatic switching control when the condition is met; when spare power automatic switching control is started, a control system of a target offshore converter station is modified, a frequency adjusting ring and a voltage adjusting ring are introduced to adjust the voltage amplitude, phase and frequency of a bus of a prepared current collection line, and meanwhile basic parameters of frequency adjustment and voltage adjustment are set; after spare power automatic switching control is started, a voltage amplitude deviation value, a voltage phase deviation value and a frequency deviation value of a power failure current collection line bus and a standby current collection line bus are detected, and whether the voltage amplitude value and the frequency of the power failure current collection line bus exceed preset limiting values or not is detected; and according to a detection result, sending a switching-on instruction to a connection section circuit breaker between the power failure current collection circuit bus and the preparation current collection circuit bus.

Description

Technical Field

[0001] The invention relates to a synchronous standby automatic switching method and system for offshore wind power collection lines, belonging to the technical field of offshore converter station control. Background Art

[0002] Offshore wind power projects generally have onshore centralized control stations and offshore converter stations (or booster stations). Offshore wind turbines are connected to the offshore converter station (or booster station) through 66kV or 220kV collector lines, and the wind turbine-side busbar (hereinafter also referred to as the collector line busbar) is connected to the transformer. The voltage is then stepped up or converted into DC and sent to the onshore centralized control station and connected to the power grid.

[0003] The collector line busbar of the offshore converter station (or booster station) is generally designed according to the single busbar segmented wiring scheme. The different transformer wind turbine side busbars are connected through segmented circuit breakers. In the offshore wind power projects that have been put into operation, the segmented circuit breakers of the collector line are in the open state during normal operation. When a connecting transformer fails, the 66kV segmented circuit breaker is closed manually.

[0004] The main reason for adopting the above operation plan is that, unlike the substation, the bus where the collector line is located is a bidirectional power supply, and both the grid side and the wind turbine side are powered. When the connecting transformer fails and stops operating, the fan side will keep the bus voltage at a high level, resulting in the traditional backup automatic or quick-cutting devices unable to operate correctly, and the automatic switching plan cannot be adopted. Therefore, we can only wait for the fans on the bus on the wind turbine side connected to the faulty connecting transformer to stop running. After the bus is free of pressure, the bus is closed with the normally operating bus by manual closing, and then the stopped fan is manually restarted.

[0005] The document "A New Automatic Backup Scheme for New Energy Access" proposes to reduce the bus voltage on the wind turbine side connected to the faulty connecting transformer by means of energy-consuming devices, but the construction cost of the offshore platform is high, so the engineering value of this scheme is low. At the same time, according to the document, it can be found that when a connecting transformer fails, the voltage of the corresponding wind turbine collector line temporarily drops below the rated voltage due to the large fault current. After the fault is removed, the collector line voltage will gradually increase and exceed the rated voltage because the wind turbine power cannot be delivered. This is the fault characteristic of the offshore wind power collector line.

[0006] In addition, there are three main solutions:

[0007] 1. The automatic switching function is not set. If the connecting transformer fails and the collector line loses power, manual intervention is required to close the circuit breaker;

[0008] 2. Setting up energy-consuming devices to stabilize the voltage of the collector line to realize the segmented closing function. This solution is relatively costly.

[0009] 3. The backup automatic switching function is achieved by quickly identifying faults and quickly switching on and off. Although this solution is low-cost, it does not take into account the fact that the voltage amplitude, phase, and frequency of the collector line connected to the faulty transformer are inconsistent with the normally operating collector line, resulting in a surge current when closing the circuit. Summary of the invention

[0010] In order to solve the problems existing in the above-mentioned prior art, the present invention proposes a method and system for synchronous standby automatic switching of offshore wind power collection lines. Through a flexible DC system control strategy, the voltage amplitude, phase and frequency of the normally operating collection line bus and the standby automatic switching collection line bus are synchronized, thereby realizing synchronous standby automatic switching.

[0011] The technical solution of the present invention is as follows:

[0012] On the one hand, the present invention provides a synchronous standby automatic switching method for offshore wind power collection lines, which is applied to an offshore converter station with a number of connected transformers greater than or equal to 2, and comprises the following steps:

[0013] Set the start conditions of the standby automatic control. When the conditions are met, start the standby automatic control.

[0014] When starting the standby automatic transfer control, modify the control system of the target offshore converter station, introduce the frequency regulation loop and the voltage regulation loop to adjust the voltage amplitude, phase and frequency of the standby collector line bus, and set the basic parameters of frequency regulation and voltage regulation;

[0015] After starting the standby automatic control, detect the voltage amplitude deviation, voltage phase deviation and frequency deviation of the power-off collector line bus and the standby collector line bus, and detect whether the voltage amplitude and frequency of the power-off collector line bus exceed the preset limit. According to the detection results, send a closing command to the connecting section circuit breaker between the power-off collector line bus and the standby collector line bus.

[0016] As a preferred implementation, the start-up conditions of the standby automatic control are to simultaneously meet the following requirements:

[0017] a1. The position of the circuit breaker on the fan side of any connected transformer is detected to change from closed position to open position;

[0018] a2. The control system did not receive the locking command;

[0019] a3. The control system receives a protection action start instruction.

[0020] As a preferred embodiment, the step of introducing a frequency adjustment loop and a voltage adjustment loop to adjust the voltage amplitude, phase and frequency of the reserve collector line bus comprises:

[0021] The frequency regulation loop is introduced to adjust the frequency setting value of the AC side voltage output by the original converter station WFMMC controller to: f ref +f k -f, where f ref is the frequency setting value of the AC side voltage output by the WFMMC controller of the original converter station, f k is the voltage frequency of the power-off collector line bus, and f is the voltage frequency of the standby collector line bus;

[0022] The voltage regulation loop is introduced to adjust the d-axis voltage set value of the AC side voltage output by the original converter station WFMMC controller to: u wddef -Δu wdk , adjust the q-axis voltage set value of the AC side voltage output by the original converter station WFMMC controller to u wqdef -Δu wqk ; Among them, u wddef is the d-axis voltage given value of the AC side voltage output by the WFMMC controller of the original converter station, u wqdef is the q-axis voltage given value of the AC side voltage output by the WFMMC controller of the original converter station, Δu wdk and Δu wqk They are respectively the d-axis given voltage adjustment value and the q-axis given voltage adjustment value obtained by performing dq transformation on the voltage amplitude and voltage phase difference of the standby collector line bus of the power-off collector line bus.

[0023] As a preferred embodiment, the step of setting basic parameters of frequency regulation and voltage regulation includes:

[0024] The basic parameters for setting frequency regulation include: upper limit of frequency regulation, lower limit of frequency regulation and frequency regulation steps;

[0025] The basic parameters for setting voltage regulation include: d-axis given voltage amplitude adjustment upper limit, d-axis given voltage amplitude adjustment lower limit, d-axis given voltage amplitude adjustment step, q-axis given voltage amplitude adjustment upper limit, q-axis given voltage amplitude adjustment lower limit and q-axis given voltage amplitude adjustment step.

[0026] As a preferred implementation, the step of sending a closing command according to the detection result includes:

[0027] If it is detected that the voltage amplitude deviation value, voltage phase deviation value and frequency deviation value of the power-off collector line bus and the standby collector line bus are all less than the limit value, a closing command is sent to the connecting section circuit breaker between the power-off collector line bus and the standby collector line bus;

[0028] If it is detected that the voltage amplitude and frequency of the power-off collector line bus exceed the preset limit, a closing command is sent to the connecting section circuit breaker between the power-off collector line bus and the standby collector line bus, and the frequency adjustment loop and voltage adjustment loop are exited at the same time, and the standby automatic transfer control is exited.

[0029] On the other hand, the present invention also proposes an offshore wind power collection line synchronous standby automatic switching system, which is applied to an offshore converter station with a number of connected transformers greater than or equal to 2, comprising:

[0030] The start control module is used to set the start conditions of the standby automatic control. When the conditions are met, the standby automatic control is started;

[0031] The parameter adjustment module is used to modify the control system of the target offshore converter station when starting the standby automatic transfer control, introduce the frequency adjustment loop and the voltage adjustment loop to adjust the voltage amplitude, phase and frequency of the standby collector line bus, and set the basic parameters of frequency adjustment and voltage adjustment at the same time;

[0032] The closing control module is used to detect the voltage amplitude deviation, voltage phase deviation and frequency deviation of the power-off collector line bus and the standby collector line bus after starting the standby automatic control, and to detect whether the voltage amplitude and frequency of the power-off collector line bus exceed the preset limit, and send a closing command to the connecting section circuit breaker between the power-off collector line bus and the standby collector line bus according to the detection results.

[0033] As a preferred implementation, the start-up conditions of the standby automatic control are to simultaneously meet the following requirements:

[0034] a1. The position of the circuit breaker on the fan side of any connected transformer is detected to change from closed position to open position;

[0035] a2. The control system did not receive the locking command;

[0036] a3. The control system receives a protection action start instruction.

[0037] As a preferred embodiment, the step of introducing a frequency adjustment loop and a voltage adjustment loop to adjust the voltage amplitude, phase and frequency of the reserve collector line bus comprises:

[0038] The frequency regulation loop is introduced to adjust the frequency setting value of the AC side voltage output by the original converter station WFMMC controller to: f ref +f k -f, where f ref is the frequency setting value of the AC side voltage output by the WFMMC controller of the original converter station, f k is the voltage frequency of the power-off collector line bus, and f is the voltage frequency of the standby collector line bus;

[0039] The voltage regulation loop is introduced to adjust the d-axis voltage set value of the AC side voltage output by the original converter station WFMMC controller to: u wddef -Δu wdk , adjust the q-axis voltage set value of the AC side voltage output by the original converter station WFMMC controller to u wqdef -Δu wqk ; Among them, u wddef is the d-axis voltage given value of the AC side voltage output by the WFMMC controller of the original converter station, u wqdef is the q-axis voltage given value of the AC side voltage output by the WFMMC controller of the original converter station, Δu wdk and Δu wqk They are respectively the d-axis given voltage adjustment value and the q-axis given voltage adjustment value obtained by performing dq transformation on the voltage amplitude and voltage phase difference of the standby collector line bus of the power-off collector line bus.

[0040] As a preferred embodiment, the step of setting basic parameters of frequency regulation and voltage regulation includes:

[0041] The basic parameters for setting frequency regulation include: upper limit of frequency regulation, lower limit of frequency regulation and frequency regulation steps;

[0042] The basic parameters for setting voltage regulation include: d-axis given voltage amplitude adjustment upper limit, d-axis given voltage amplitude adjustment lower limit, d-axis given voltage amplitude adjustment step, q-axis given voltage amplitude adjustment upper limit, q-axis given voltage amplitude adjustment lower limit and q-axis given voltage amplitude adjustment step.

[0043] As a preferred implementation, the step of sending a closing command according to the detection result includes:

[0044] If it is detected that the voltage amplitude deviation value, voltage phase deviation value and frequency deviation value of the power-off collector line bus and the standby collector line bus are all less than the limit value, a closing command is sent to the connecting section circuit breaker between the power-off collector line bus and the standby collector line bus;

[0045] If it is detected that the voltage amplitude and frequency of the power-off collector line bus exceed the preset limit, a closing command is sent to the connecting section circuit breaker between the power-off collector line bus and the standby collector line bus, and the frequency adjustment loop and voltage adjustment loop are exited at the same time, and the standby automatic transfer control is exited.

[0046] Additional aspects and advantages of the present invention will be set forth in the following description, and some of them will be apparent from the description, or may be understood by practicing the present invention. In addition, the various aspects and advantages of the present invention may be realized and obtained by the method steps and combinations particularly pointed out in the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 This is a wiring diagram of an offshore converter station in an embodiment of the present invention;

[0048] Figure 2 This is a schematic diagram of a process of Embodiment 1 of the present invention;

[0049] Figure 3 This is an example diagram of the original WFMMC control strategy of the offshore converter station in an embodiment of the present invention;

[0050] Figure 4 This is a schematic diagram of the control strategy after adding the standby automatic switching control logic in an embodiment of the present invention. DETAILED DESCRIPTION

[0051] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0052] It should be understood that the step numbers used in this document are only for convenience of description and are not intended to limit the order in which the steps are executed.

[0053] It should be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0054] The terms “include” and “comprising” indicate the presence of described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0055] The term "and / or" means and includes any and all possible combinations of one or more of the associated listed items.

[0056] Embodiment 1:

[0057] This embodiment provides a synchronous standby automatic switching method for offshore wind power collection lines, which is applied to an offshore converter station with a number of connected transformers greater than or equal to 2. The number of connected transformer wind turbine side windings is not limited. This embodiment only describes the synchronous standby automatic switching strategy of the segmented circuit breaker of the collection line busbar connected to the wind turbine side of the transformer. This embodiment is described by taking two double-winding connected transformers as an example. For details, see Figure 1 , Figure 1Middle: #1 connected to the wind turbine side circuit breaker is DL1, #1 connected to the wind turbine side current transformer is CT1, #1 connected to the wind turbine side collector line bus voltage transformer is PT1; #2 connected to the wind turbine side circuit breaker is DL2, #2 connected to the wind turbine side current transformer is CT2, #2 connected to the wind turbine side collector line bus voltage transformer is PT2; #1 connected to the wind turbine side collector line bus and #2 connected to the wind turbine side collector line bus connection section breaker is DL3. Each section of the collector line bus is connected to the collector lines of several wind turbines.

[0058] To facilitate the description of this embodiment, the following definitions are given:

[0059] Power outage collector line bus: The fan side circuit breaker of a certain connecting transformer is tripped, causing the corresponding collector line bus to lose the power supply on the converter side. For example, if the #1 connecting transformer fails and causes DL1 to be disconnected, bus 1 is the "power outage collector line bus". If the #2 connecting transformer fails and causes DL2 to be disconnected, bus 2 is the "power outage collector line bus".

[0060] Reserve collector line bus: The bus in operation that is connected to the "power-off collector line bus" through the bus section switch is the "reserve collector line bus". For example, if the #1 connecting transformer fails and causes DL1 to be disconnected, bus 2 is the "reserve collector line bus". If the #2 connecting transformer fails and causes DL2 to be disconnected, bus 1 is the "reserve collector line bus".

[0061] See Figure 2 The synchronous standby automatic start-up method of the offshore wind power collection line proposed in this embodiment specifically includes the following steps:

[0062] S100, setting the start-up conditions of the standby automatic control, and starting the standby automatic control when the conditions are met; specifically, in this embodiment, the start-up conditions of the standby automatic control are to simultaneously meet the following requirements:

[0063] a1. It is detected that the position of a circuit breaker (DL1 or DL2) on the fan side of a certain connection transformer changes from closed position to open position;

[0064] a2. The control system has not received any blocking instructions, including manual opening blocking, collector line busbar protection blocking, connection transformer backup protection action blocking, etc.;

[0065] a3. The control system receives the protection action start instruction, including the main transformer electrical main protection action start and the main transformer non-electrical protection action start.

[0066] S200, when starting the standby automatic transfer control, modify the control system of the target offshore converter station, introduce the frequency adjustment loop and the voltage adjustment loop to adjust the voltage amplitude, phase and frequency of the standby collector line bus, and set the basic parameters of frequency adjustment and voltage adjustment; specifically, S200 includes the following steps:

[0067] S201, collect the voltage amplitude, phase and frequency of PT1 and PT2, and set the voltage amplitude u of the "power-off collector line bus" Tabc , the voltage phase is θ Tabc and the voltage frequency is f k , assuming that the voltage amplitude of the “prepared collector line bus” is u Yabc , the voltage phase is θ Yabc and the voltage frequency is f;

[0068] S202. Offshore converter stations generally use a constant AC voltage control method, and the converter control strategy is WFMMC (wind farm modular multilevel converter, see Figure 3 ), the d-axis voltage given value u of the voltage on the given AC side of the converter wdref and q-axis voltage given value u wqref , and the frequency setting value f of the AC side voltage ref , thereby controlling the voltage amplitude, phase and frequency on the AC side of the converter.

[0069] This embodiment adds a frequency regulation loop and a voltage regulation loop to the original WFMMC control strategy, thereby controlling the AC side voltage of the converter, and then changing the voltage amplitude, phase and frequency of the "prepared collector line bus". The modified control strategy is shown in Figure 4 .

[0070] Specifically, the introduced frequency regulation loop adjusts the frequency setting value of the AC side voltage output by the original converter station WFMMC controller to: ref +f k -f, where f ref is the frequency setting value of the AC side voltage output by the WFMMC controller of the original converter station, f k is the voltage frequency of the power-off collector line bus, and f is the voltage frequency of the standby collector line bus;

[0071] Frequency regulation must comply with the upper and lower limits and the limits of the frequency regulation step. Assume that the upper limit of frequency regulation is f max , the lower limit of frequency adjustment is f min , the frequency adjustment step is df. The limit application scheme is as follows:

[0072] ①, when f ref +f k -f>f max When f ref +f k -f=f max ;

[0073] ②, when fref +f k -f < f min When, let f rrf +f k -f = f min ;

[0074] ③. Let the sampling period be Δt, and let the frequency reference value at time t be (f ref +f k -f) t , and let the frequency reference value at time t + Δt be (f ref +f k -f) t+Δt ; If (f ref +f k -f)t + Δt - (fref + fk - f)t ≥ df, modify the frequency reference value, and let (f ref +f k -f) t+Δt =(f ref +f k -f) t+Δt ; If (f ref +f k -f) t+Δt -(f ref +f k -f) t < df, do not modify the frequency reference value, and let (f ref +f k -f)t + Δt = (fref + fk - f)t.

[0075] Specifically, the introduced voltage regulation loop performs dq transformation on (u Yabc -u Tabc ) and (θ Yabc -θ Tabc ) to obtain the d-axis given voltage regulation value Δu wdk and the q-axis given voltage regulation value Δu wqk ; The d-axis given voltage amplitude of the original WFMMC is changed to the new d-axis given voltage amplitude as u wddef -Δu wdk ; The q-axis given voltage amplitude of the original WFMMC is changed to the new q-axis given voltage amplitude as u wqdef -Δu wqk .

[0076] The set basic parameters of voltage regulation include: the upper limit of the d-axis given voltage amplitude regulation is u dmax , the lower limit of the d-axis given voltage amplitude regulation is u dmin , the step of the d-axis given voltage amplitude regulation is du d ; The upper limit of the q-axis given voltage amplitude regulation is u qmax, the lower limit of the q-axis given voltage amplitude adjustment is u qmin , the q-axis given voltage amplitude adjustment step is du q .

[0077] The d-axis limit application scheme is as follows:

[0078] ①. When u wddef -Δu wdk >u dmax When u wddef -Δu wdk =u dmax ;

[0079] ②. When u wddef -Δu wdk dmin When u wddef -Δu wdk =u dmin ;

[0080] ③、Assume that the given voltage amplitude of the d-axis at time t is (u wddef -Δu wdk ) t , assuming that the given voltage amplitude of the d-axis at time t+Δt is (u wddef -Δu wdk ) t+Δt , if (u wdded -Δu wfk ) t+Δt -(u wddef -Δu wdk ) t ≥du d When the d-axis given voltage amplitude is modified, let (u wddef -Δu wdk ) t+Δt =(u wddef -Δu wdk ) t+Δt ;if (u wddef -Δu wdk ) t+Δt -(u wddef -Δu wdk ) t <du d When the d-axis given voltage amplitude is not modified, let (u wddef -Δu wdk ) t+Δt =(u wddef -Δu wdk ) t .

[0081] The q-axis limit application scheme is as follows:

[0082] ①. When u​wqdef -Δu wqk >u qmax When u wqdef -Δu wqk =u qmax ;

[0083] ②. When u wqdef -Δu wqk qmin When u wqdef -Δu wqk =u qmin ;

[0084] ③, Assume that the given voltage amplitude of the q-axis at time t is (u wqdef -Δu wqk ) t , assuming that the q-axis given voltage amplitude at time t+Δt is (u wqdef -Δu wqk ) t+Δt , if (u wqdef -Δuwqk)t+Δt-(uwqdef-Δuwqk)t≥duq, modify the given value of the q-axis given voltage amplitude, and set (u wqdef -Δu wqk ) t+Δt =(u wqdef -Δu wqk ) t+Δt ; if (u wqdef -Δu wqk ) t+Δt -(u wqdef -Δu wqk ) t <du q When the q-axis given voltage amplitude is not modified, let (u wqdef -Δu wqk ) t+Δt =(u wqdef -Δu wqk ) t .

[0085] S300, after starting the standby automatic transfer control, close the power-off collector line bus and the standby collector line bus in accordance with the following steps:

[0086] S301, set the closed loop allowable voltage amplitude deviation value of the power-off collector line bus and the standby collector line bus to u AL , the allowable voltage phase deviation value is θ AL , the allowable frequency deviation value is f AL ;

[0087] S302: If the voltage amplitude deviation value of the power-off collector line bus and the standby collector line bus is detected,​Tabc -u Yabc | AL , and the voltage phase deviation value |θ Tabc -θ Yabc |<θ AL , and the frequency deviation value |f k -f| <f AL , then send a closing command to the DL3 circuit breaker;

[0088] S303. If it is detected that the voltage amplitude and frequency of the power-off collector line bus exceed the limit values ​​specified in the specification, a closing command is sent to the connecting section circuit breaker between the power-off collector line bus and the standby collector line bus, and the frequency adjustment loop and voltage adjustment loop are exited at the same time, and the standby automatic transfer control is exited.

[0089] Based on the above implementation scheme, the standby automatic switching control method proposed in this embodiment controls the grid-side AC voltage of the converter to make the voltage amplitude, phase and frequency of the standby collection line bus and the power-off collection line bus similar, thereby reducing the impact current when closing the section circuit breaker, reducing the risk of system collapse during standby automatic switching, and improving reliability.

[0090] Embodiment 2:

[0091] This embodiment provides an offshore wind power collection line synchronous standby automatic switching system, which is applied to an offshore converter station with a number of connected transformers greater than or equal to 2, including:

[0092] A start control module is used to set the start conditions of the standby automatic control, and when the conditions are met, the standby automatic control is started; this module is used to implement the function of step S100 in the first embodiment, and will not be repeated here;

[0093] A parameter adjustment module is used to modify the control system of the target offshore converter station when starting the standby automatic transfer control, introduce a frequency adjustment loop and a voltage adjustment loop to adjust the voltage amplitude, phase and frequency of the standby collector line bus, and set basic parameters of frequency adjustment and voltage adjustment at the same time; this module is used to implement the function of step S200 in the first embodiment, and will not be repeated here;

[0094] The closing control module is used to detect the voltage amplitude deviation value, voltage phase deviation value and frequency deviation value of the power-off collector line bus and the standby collector line bus after starting the standby automatic control, and detect whether the voltage amplitude and frequency of the power-off collector line bus exceed the preset limit value, and send a closing command to the connecting section circuit breaker between the power-off collector line bus and the standby collector line bus according to the detection result; this module is used to implement the function of step S300 in Example 1, which will not be repeated here.

[0095] As a preferred implementation of this embodiment, the start-up condition of the standby automatic switching control is to simultaneously meet the following requirements:​

[0096] a1. The position of the circuit breaker on the fan side of any connected transformer is detected to change from closed position to open position;

[0097] a2. The control system did not receive the locking command;

[0098] a3. The control system receives a protection action start instruction.

[0099] As a preferred implementation of this embodiment, the step of introducing a frequency adjustment loop and a voltage adjustment loop to adjust the voltage amplitude, phase and frequency of the reserve collector line bus includes:

[0100] The frequency regulation loop is introduced to adjust the frequency setting value of the AC side voltage output by the original converter station WFMMC controller to: f ref +f k -f, where f ref is the frequency setting value of the AC side voltage output by the WFMMC controller of the original converter station, f k is the voltage frequency of the power-off collector line bus, and f is the voltage frequency of the standby collector line bus;

[0101] The voltage regulation loop is introduced to adjust the d-axis voltage set value of the AC side voltage output by the original converter station WFMMC controller to: u wddef -Δu wdk , adjust the q-axis voltage set value of the AC side voltage output by the original converter station WFMMC controller to u wqdef -Δu wqk ; Among them, u wddef is the d-axis voltage given value of the AC side voltage output by the WFMMC controller of the original converter station, u wqdef is the q-axis voltage given value of the AC side voltage output by the WFMMC controller of the original converter station, Δu wdk and Δu wqk They are respectively the d-axis given voltage adjustment value and the q-axis given voltage adjustment value obtained by performing dq transformation on the voltage amplitude and voltage phase difference of the standby collector line bus of the power-off collector line bus.

[0102] As a preferred implementation of this embodiment, the step of setting basic parameters of frequency regulation and voltage regulation includes:

[0103] The basic parameters for setting frequency regulation include: upper limit of frequency regulation, lower limit of frequency regulation and frequency regulation steps;

[0104] The basic parameters for setting voltage regulation include: d-axis given voltage amplitude adjustment upper limit, d-axis given voltage amplitude adjustment lower limit, d-axis given voltage amplitude adjustment step, q-axis given voltage amplitude adjustment upper limit, q-axis given voltage amplitude adjustment lower limit and q-axis given voltage amplitude adjustment step.

[0105] As a preferred implementation of this embodiment, the step of sending a closing instruction according to the detection result includes:

[0106] If it is detected that the voltage amplitude deviation value, voltage phase deviation value and frequency deviation value of the power-off collector line bus and the standby collector line bus are all less than the limit value, a closing command is sent to the connecting section circuit breaker between the power-off collector line bus and the standby collector line bus;

[0107] If it is detected that the voltage amplitude and frequency of the power-off collector line bus exceed the preset limit, a closing command is sent to the connecting section circuit breaker between the power-off collector line bus and the standby collector line bus, and the frequency adjustment loop and voltage adjustment loop are exited at the same time, and the standby automatic transfer control is exited.

[0108] Embodiment three:

[0109] This embodiment proposes an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, a synchronous standby automatic switching method for offshore wind power collection lines as described in any embodiment of the present invention is implemented.

[0110] Embodiment 4:

[0111] This embodiment provides a computer-readable storage medium having a computer program stored thereon. When the program is executed by a processor, a synchronous standby automatic switching method for an offshore wind power collection line as described in any embodiment of the present invention is implemented.

[0112] In the embodiments of the present application, "at least one" refers to one or more, and "more than one" refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent the existence of A alone, the existence of A and B at the same time, and the existence of B alone. Among them, A and B can be singular or plural. The character " / " generally indicates that the previous and next associated objects are in an "or" relationship. "At least one of the following" and similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b and c can be represented by: a, b, c, a and b, a and c, b and c, or a and b and c, where a, b, c can be single or multiple.

[0113] Those of ordinary skill in the art will appreciate that the various units and algorithm steps described in the embodiments disclosed herein can be implemented in a combination of electronic hardware, computer software, and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0114] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0115] In several embodiments provided in the present application, if any function is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (Read-Only Memory; hereinafter referred to as: ROM), random access memory (Random Access Memory; hereinafter referred to as: RAM), disk or optical disk, and other media that can store program codes.

[0116] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A synchronous standby automatic switching method for offshore wind power collection lines, applied to an offshore converter station with a number of connected transformers greater than or equal to 2, characterized in that: The following steps are involved: Set the start conditions of the standby automatic control. When the conditions are met, start the standby automatic control. When starting the standby automatic transfer control, modify the control system of the target offshore converter station, introduce the frequency regulation loop and the voltage regulation loop to adjust the voltage amplitude, phase and frequency of the standby collector line bus, and set the basic parameters of frequency regulation and voltage regulation; After starting the standby automatic control, detect the voltage amplitude deviation, voltage phase deviation and frequency deviation of the power-off collector line bus and the standby collector line bus, and detect whether the voltage amplitude and frequency of the power-off collector line bus exceed the preset limit. According to the detection results, send a closing command to the connecting section circuit breaker between the power-off collector line bus and the standby collector line bus.

2. A synchronous standby automatic switching method for offshore wind power collection lines according to claim 1, characterized in that: The startup conditions of the standby automatic control are to meet the following requirements at the same time: a1. The position of the circuit breaker on the fan side of any connected transformer is detected to change from closed position to open position; a2. The control system did not receive the locking command; a3. The control system receives a protection action start instruction.

3. The method for synchronous standby automatic switching of offshore wind power collection lines according to claim 1, characterized in that: The step of introducing a frequency adjustment loop and a voltage adjustment loop to adjust the voltage amplitude, phase and frequency of the reserve collector line bus comprises: The frequency regulation loop is introduced to adjust the frequency setting value of the AC side voltage output by the original converter station WFMMC controller to: f ref +f k -f, where f ref is the frequency setting value of the AC side voltage output by the WFMMC controller of the original converter station, f k is the voltage frequency of the power-off collector line bus, and f is the voltage frequency of the standby collector line bus; The voltage regulation loop is introduced to adjust the d-axis voltage set value of the AC side voltage output by the original converter station WFMMC controller to: u wddef -Δu wdk , adjust the q-axis voltage set value of the AC side voltage output by the original converter station WFMMC controller to u wqdef -Δu wqk ; Among them, u wddef is the d-axis voltage given value of the AC side voltage output by the WFMMC controller of the original converter station, u wqdef is the q-axis voltage given value of the AC side voltage output by the WFMMC controller of the original converter station, Δu wdk and Δu wqk They are respectively the d-axis given voltage adjustment value and the q-axis given voltage adjustment value obtained by performing dq transformation on the voltage amplitude and voltage phase difference of the standby collector line bus of the power-off collector line bus.

4. A synchronous standby automatic switching method for offshore wind power collection lines according to claim 3, characterized in that: The steps of setting basic parameters of frequency regulation and voltage regulation include: The basic parameters for setting frequency regulation include: upper limit of frequency regulation, lower limit of frequency regulation and frequency regulation steps; The basic parameters for setting voltage regulation include: d-axis given voltage amplitude adjustment upper limit, d-axis given voltage amplitude adjustment lower limit, d-axis given voltage amplitude adjustment step, q-axis given voltage amplitude adjustment upper limit, q-axis given voltage amplitude adjustment lower limit and q-axis given voltage amplitude adjustment step.

5. The method for synchronous standby automatic switching of offshore wind power collection lines according to claim 1, characterized in that: The step of sending a closing command according to the detection result comprises: If it is detected that the voltage amplitude deviation value, voltage phase deviation value and frequency deviation value of the power-off collector line bus and the standby collector line bus are all less than the limit value, a closing command is sent to the connecting section circuit breaker between the power-off collector line bus and the standby collector line bus; If it is detected that the voltage amplitude and frequency of the power-off collector line bus exceed the preset limit, a closing command is sent to the connecting section circuit breaker between the power-off collector line bus and the standby collector line bus, and the frequency adjustment loop and voltage adjustment loop are exited at the same time, and the standby automatic transfer control is exited.

6. An offshore wind power collection line synchronous standby automatic switching system, applied to an offshore converter station with more than or equal to 2 connected transformers, characterized in that: include: The start control module is used to set the start conditions of the standby automatic control. When the conditions are met, the standby automatic control is started; The parameter adjustment module is used to modify the control system of the target offshore converter station when starting the standby automatic transfer control, introduce the frequency adjustment loop and the voltage adjustment loop to adjust the voltage amplitude, phase and frequency of the standby collector line bus, and set the basic parameters of frequency adjustment and voltage adjustment at the same time; The closing control module is used to detect the voltage amplitude deviation, voltage phase deviation and frequency deviation of the power-off collector line bus and the standby collector line bus after starting the standby automatic control, and to detect whether the voltage amplitude and frequency of the power-off collector line bus exceed the preset limit, and send a closing command to the connecting section circuit breaker between the power-off collector line bus and the standby collector line bus according to the detection results.

7. The offshore wind power collection line synchronous standby automatic switching system according to claim 6, characterized in that: The startup conditions of the standby automatic control are to meet the following requirements at the same time: a1. The position of the circuit breaker on the fan side of any connected transformer is detected to change from closed position to open position; a2. The control system did not receive the locking command; a3. The control system receives a protection action start instruction.

8. The offshore wind power collection line synchronous standby automatic switching system according to claim 6, characterized in that: The step of introducing a frequency adjustment loop and a voltage adjustment loop to adjust the voltage amplitude, phase and frequency of the reserve collector line bus comprises: The frequency regulation loop is introduced to adjust the frequency setting value of the AC side voltage output by the original converter station WFMMC controller to: f ref +f k -f, where f ref is the frequency setting value of the AC side voltage output by the WFMMC controller of the original converter station, f k is the voltage frequency of the power-off collector line bus, and f is the voltage frequency of the standby collector line bus; The voltage regulation loop is introduced to adjust the d-axis voltage set value of the AC side voltage output by the original converter station WFMMC controller to: u wddef -Δu wdk , adjust the q-axis voltage set value of the AC side voltage output by the original converter station WFMMC controller to u wqdef -Δu wqk ; Among them, u wddef is the d-axis voltage given value of the AC side voltage output by the WFMMC controller of the original converter station, u wqdef is the q-axis voltage given value of the AC side voltage output by the WFMMC controller of the original converter station, Δu wdk and Δu wqk They are respectively the d-axis given voltage adjustment value and the q-axis given voltage adjustment value obtained by performing dq transformation on the voltage amplitude and voltage phase difference of the standby collector line bus of the power-off collector line bus.

9. The offshore wind power collection line synchronous standby automatic switching system according to claim 8, characterized in that: The steps of setting basic parameters of frequency regulation and voltage regulation include: The basic parameters for setting frequency regulation include: upper limit of frequency regulation, lower limit of frequency regulation and frequency regulation steps; The basic parameters for setting voltage regulation include: d-axis given voltage amplitude adjustment upper limit, d-axis given voltage amplitude adjustment lower limit, d-axis given voltage amplitude adjustment step, q-axis given voltage amplitude adjustment upper limit, q-axis given voltage amplitude adjustment lower limit and q-axis given voltage amplitude adjustment step.

10. An offshore wind power collection line synchronous standby automatic switching system according to claim 6, characterized in that: The step of sending a closing command according to the detection result comprises: If it is detected that the voltage amplitude deviation value, voltage phase deviation value and frequency deviation value of the power-off collector line bus and the standby collector line bus are all less than the limit value, a closing command is sent to the connecting section circuit breaker between the power-off collector line bus and the standby collector line bus; If it is detected that the voltage amplitude and frequency of the power-off collector line bus exceed the preset limit, a closing command is sent to the connecting section circuit breaker between the power-off collector line bus and the standby collector line bus, and the frequency adjustment loop and voltage adjustment loop are exited at the same time, and the standby automatic transfer control is exited.

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