A dynamic networking coordination control method and device for an off-grid wind-load storage system

Abstract

The present invention belongs to the field of wind power generation and energy storage technology, and discloses a dynamic networking coordination control method and device for an off-grid wind-load storage system; the device: the output end of the wind turbine is divided into two paths, one path is connected to the input end of the box-type transformer T1 through the circuit breaker K1, and the other path is connected to the input end of the box-type transformer T1 through the wind turbine converter; the output end of the box-type transformer T1 is connected to one end of the circuit breaker K2 through a cable, and the other end of the circuit breaker K2 is connected to the high-voltage bus; the energy storage system is connected to the high-voltage bus through the box-type transformer T2; the reactive standby load P1 and the active load P2 are both connected to the high-voltage bus. In the present invention, a reactive standby load P1 and an active load P2 are provided; when the reactive load is insufficient during the start-up phase of the wind turbine, a standby reactive load is put into operation; when the wind turbine begins to absorb reactive power during startup, the reactive load is gradually cut out, thereby achieving system voltage stability and avoiding system overvoltage problems caused by long cables.

Description

Technical Field

[0001] The present invention belongs to the technical field of wind power generation and energy storage, and in particular relates to a dynamic networking coordination control method and device for an off-grid wind-load storage system. Background Art

[0002] In recent years, with global energy shortages and increasingly prominent environmental issues caused by traditional power generation, wind power generation has rapidly developed due to its mature technology and commercial potential. Off-grid wind power systems can operate independently without the support of a large power grid, providing power to their surrounding areas and playing a significant role in alleviating power supply constraints. However, wind power generation is volatile and random. Wind speed fluctuations cause corresponding fluctuations in wind turbine output power, resulting in poor power generation stability. This leads to a series of problems such as fluctuations in wind power output, output voltage, and frequency, which can even threaten the stability and safety of the system. Currently, most research on wind power generation focuses on grid-connected wind power, while relatively little research has been conducted on off-grid wind power generation. In off-grid wind power generation systems, the aforementioned problems are even more prominent due to the lack of effective support from the large power grid. Most research on off-grid wind power generation focuses on situations where grid-connected wind power generation systems transition to isolated grid operation due to certain reasons. This research has not considered the issues that arise during black starts of wind power generation systems or the dynamic networking of off-grid wind-load storage systems. Summary of the Invention

[0003] The purpose of the present invention is to provide a method and device for dynamic networking coordination control of an off-grid wind-load storage system to solve the problems existing in the black start of a wind power generation system and the dynamic networking operation of an off-grid wind-load storage system.

[0004] In a first aspect, the present invention provides a dynamic networking coordination control device for an off-grid wind-load storage system, comprising:

[0005] Wind turbine, energy storage system, box-type transformer T1, cables, box-type transformer T2, reactive standby load P1, active load P2 and high-voltage busbar;

[0006] The output end of the fan is divided into two paths. One path is connected to the input end of the box-type transformer T1 through the circuit breaker K1, and the other path is connected to the input end of the box-type transformer T1 through the fan converter. The output end of the box-type transformer T1 is connected to one end of the circuit breaker K2 through a cable, and the other end of the circuit breaker K2 is connected to the high-voltage busbar.

[0007] The energy storage system is connected to the high-voltage busbar through the box-type transformer T2;

[0008] The reactive standby load P1 and the active load P2 are both connected to the high-voltage bus.

[0009] A further improvement of the present invention is that the energy storage system uses a plurality of energy storage devices connected in parallel.

[0010] A further improvement of the present invention is that the energy storage system adopts virtual synchronous control, which is divided into active frequency control and reactive voltage control, which are respectively used to simulate the speed regulation and excitation system of the synchronous generator.

[0011] A further improvement of the present invention is that the energy storage system is a voltage source type energy storage system.

[0012] A further improvement of the present invention is that it also includes a load power control device; the load power control device is used to measure the active power and reactive power generated by the wind turbine; and control the switching of the reactive standby load P1 and the active load P2.

[0013] In a second aspect, the present invention provides a control method for a dynamic networking coordination control device of an off-grid wind-load storage system, comprising:

[0014] Disconnect circuit breaker K2, start the energy storage system, and put active load into operation. Operation, forming an off-grid load storage system;

[0015] When the output voltage and power of the off-grid load storage system are stable and operating normally, close the circuit breaker K2 and connect the wind turbine;

[0016] Measure the reactive power Q0 generated by the wind turbine and input an equal reactive load from the reactive standby load P1

[0017] The wind turbine converter starts to modulate, establishing a stable DC bus voltage between the rectifier and inverter of the wind turbine converter. The voltage starts to synchronize with the energy storage side voltage. When the phase, amplitude and frequency deviations fall within the set range, the grid-connected circuit breaker K1 is closed.

[0018] Set the set values ​​of the active power and reactive power of the fan; the fan starts to output active power and reactive power and climbs at a constant speed; before the fan output reactive power climbs to the set value, gradually reduce the reactive load input from the reactive standby load P1;

[0019] When the active power output of the fan reaches the set value, the remaining active load is put into operation. When the reactive power output reaches the set value, the reactive load in the reactive standby load P1 is completely cut off; the total capacity of the active load P1 is

[0020] A further improvement of the present invention is that the active load The size is less than 20% of the total capacity of the energy storage system.

[0021] The present invention is further improved in that: at time t1, the fan starts to generate active power and reactive power and climbs at a constant speed; at time t2, the active power output of the fan reaches the reference value. At t3, the reactive power output of the fan reaches the reference value

[0022] A further improvement of the present invention is that the active power ramp rate R of the fan is p satisfy Satisfy the unit's maximum ramp rate constraint R p ≤R Pm ; Reactive power ramp rate of the wind turbine And satisfy R Q ≤R Qm ; R Pm and R Qm They are the maximum ramp rates of active power and reactive power of the wind turbine respectively.

[0023] A further improvement of the present invention is that: before the wind turbine output reactive power reaches the set value, in the step of gradually reducing the reactive load input from the reactive standby load P1, the reactive load is cut out n times; each time the reactive load is cut out, the reactive load is cut out for n times. Wherein, n is a positive integer greater than or equal to 2.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] The present invention provides a method and device for dynamic networking and coordinated control of an off-grid wind-load storage system. The device is equipped with a reactive standby load P1 and an active load P2. When the reactive load is insufficient during the wind turbine startup phase, the standby reactive load is activated. When the wind turbine begins to absorb reactive power during startup, the reactive load is gradually switched off, thereby stabilizing the system voltage and avoiding system overvoltage problems caused by long cables. The energy storage system of the present invention features flexible control and rapid response, can smooth wind power fluctuations, and effectively support the system's voltage and frequency, thereby improving system stability.

[0026] The coordinated reactive power control method for standby loads and wind turbines employed in this invention not only achieves voltage and frequency stability and accurate active power output through voltage-source energy storage, but also, thanks to the presence of long cables, avoids overvoltage issues associated with voltage-source energy storage alone by actively controlling the reactive power of the load and wind turbine. This is of great significance for the dynamic networking and stable operation of wind-load storage systems.

[0027] Through the dynamic networking coordination control method and device of the off-grid wind-storage-load system of the present invention, it is possible to break away from the support of the large power grid and realize power supply to surrounding loads. It is very suitable for pastoral areas, forest areas, islands and other areas that cannot be effectively covered by the large power grid, and is of great significance for alleviating the tension in power supply. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The accompanying drawings, which constitute part of the present invention, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0029] Figure 1 This is a structural diagram of a dynamic networking coordination control device for an off-grid wind-load storage system according to the present invention;

[0030] Figure 2 This is a structural block diagram of a load power control device of a dynamic networking coordination control device for an off-grid wind-load storage system of the present invention;

[0031] Figure 3 This is a schematic diagram of the wind turbine load power coordinated control according to the present invention. DETAILED DESCRIPTION

[0032] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments. It should be noted that, in the absence of conflict, the embodiments and features of the embodiments of the present invention can be combined with each other.

[0033] The following detailed description is an exemplary description and is intended to provide further detailed description of the present invention. Unless otherwise indicated, all technical terms used in the present invention have the same meaning as those generally understood by those skilled in the art to which the present invention belongs. The terms used in the present invention are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention.

[0034] Example 1

[0035] The wind turbine used in the present invention is a doubly fed asynchronous wind turbine generator (DFIG), and the energy storage is a voltage source type energy storage with virtual synchronous control.

[0036] See also Figure 1 As shown, the present invention provides a dynamic networking coordination control device for an off-grid wind-load storage system, including a wind turbine 1 (using a doubly-fed asynchronous wind turbine generator), an energy storage system 2, a box-type transformer T1, a cable 3, a box-type transformer T2, a reactive standby load P1, an active load P2 and a high-voltage bus 4.

[0037] Voltage source energy storage system 2 utilizes m parallel energy storage devices 21. Energy storage system 2 employs virtual synchronous control, which is divided into active frequency control and reactive voltage control, simulating the speed regulation and excitation systems of synchronous generators, respectively. After a black start, energy storage system 2 must be able to adequately respond to fluctuations in wind turbine output and load.

[0038] The output end of the wind turbine 1 is divided into two paths. One path is connected to the input end of the box-type transformer T1 through the circuit breaker K1, and the other path is connected to the input end of the box-type transformer T1 through the wind turbine converter 11. The output end of the box-type transformer T1 is connected to one end of the circuit breaker K2 through the cable 3, and the other end of the circuit breaker K2 is connected to the high-voltage bus 4.

[0039] The energy storage system 2 is connected to the high voltage bus 4 via the box-type transformer T2;

[0040] The reactive standby load P1 and the active load P2 are both connected to the high-voltage bus 4 .

[0041] See also Figure 2 As shown, the present invention discloses a dynamic networking and coordinated control device for an off-grid wind-load storage system, including a load power control device. The load power control device includes a data acquisition module and a load control unit. The data acquisition module is used to measure the active power and reactive power generated by the wind turbine, and the load control unit can control the switching of active and reactive loads. When the wind turbine circuit breaker K1 is closed, a reactive load equal to the measured wind turbine-end reactive power Q0 is switched on. When the wind turbine's active power output stabilizes, all active loads are switched on. As the wind turbine's reactive power output ramps, the reactive loads are gradually switched off.

[0042] In a specific embodiment, a first branch, a second branch, a third branch and a fourth branch are connected in parallel to the high-voltage bus 4; in the first branch, the output end of the wind turbine 1 is divided into two branches, one branch is connected to the input end of the box-type transformer T1 through the circuit breaker K1, and the other branch is connected to the input end of the box-type transformer T1 through the wind turbine converter 11; the output end of the box-type transformer T1 is connected to one end of the circuit breaker K2 through the cable 3, and the other end of the circuit breaker K2 is connected to the high-voltage bus 4; in the second branch, the energy storage system 2 is connected to the high-voltage bus 4 through the box-type transformer T2; in the third branch, the reactive standby load P1 is connected to the high-voltage bus 4; in the fourth branch, the active load P2 is connected to the high-voltage bus 4.

[0043] In a specific embodiment, a first branch, a second branch, and a third branch are connected in parallel to the high-voltage bus 4; in the first branch, the output end of the wind turbine 1 is divided into two branches, one branch is connected to the input end of the box-type transformer T1 through the circuit breaker K1, and the other branch is connected to the input end of the box-type transformer T1 through the wind turbine converter 11; the output end of the box-type transformer T1 is connected to one end of the circuit breaker K2 through the cable 3, and the other end of the circuit breaker K2 is connected to the high-voltage bus 4; in the second branch, the energy storage system 2 is connected to the high-voltage bus 4 through the box-type transformer T2; in the third branch, the reactive standby load P1 and the active load P2 are connected in series and then connected to the high-voltage bus 4.

[0044] Example 2

[0045] See also Figures 1 to 3As shown, the following is a detailed description of a dynamic networking coordination control method for an off-grid wind-storage-load system of the present invention in combination with specific implementation steps, which specifically includes the following steps:

[0046] Step 1: Disconnect circuit breaker K2, start voltage source energy storage system 2, and add a small amount of active load. Operation forms an off-grid load storage system; the voltage source energy storage system 2 adopts a virtual synchronous control mode; a small amount of active load Refers to the load used to form an off-grid load storage system, the load size of which is less than 20% of the total capacity of the voltage source energy storage system 2.

[0047] Step 2: When the output voltage and power of the off-grid load storage system are stable and operating normally, close the circuit breaker K2 and connect wind turbine 1.

[0048] Step 3: Measure the reactive power Q0 generated by the wind turbine and add an equal reactive load from the reactive standby load P1.

[0049] Step 4: The wind turbine converter 11 of wind turbine 1 starts modulation, and a stable DC bus voltage is established on the DC bus between the rectifier and inverter of the wind turbine converter 11. The voltage begins to synchronize with the energy storage side voltage. When the phase, amplitude and frequency deviations reach the set range, the grid-connected circuit breaker K1 is closed.

[0050] Step 5: Set the active power and reactive power setpoints for wind turbine 1. The active power setpoint is equal to the active load of the off-grid wind-load storage system during normal operation. The inverse of the reactive power setpoint is equal to the reactive load applied in step 3. At this point, wind turbine 1 begins to generate active power and reactive power and ramps up at a constant speed. Before wind turbine 1's output reactive power reaches the setpoint, gradually reduce the reactive load applied from reactive backup load P1.

[0051] Step 6: When the active power output of wind turbine 1 reaches the set value, the remaining active load is put into operation. (The total capacity of active load P1 is ), after the reactive power output reaches the set value, the reactive load in the reactive standby load P1 is completely cut off.

[0052] In step 1, you need to first disconnect the fan side bus switch K1 and put in a small amount of active load Ensure stable operation of the energy storage side and the load side, establish an off-grid load storage system, and output stable voltage and frequency.

[0053] In step 2-3, after the system power and frequency stabilize, K1 is closed at time t0 to connect wind turbine 1. Due to the presence of the long capacitive cable 3, the energy storage absorbs reactive power, causing the output voltage to increase. At this time, the reactive power Q0 output by the wind turbine is calculated, and the same reactive load is added from the reactive standby load P1 to prevent the energy storage from absorbing excessive reactive power.

[0054] Step 4 is the starting process of the doubly fed wind turbine 1. At this time, the machine-side and grid-side converters of the doubly fed wind turbine 1 receive instructions and act.

[0055] Step 5: After the start-up is completed, the power of wind turbine 1 will be output according to the curve at time t1, and the active power output will reach the reference value at time t2. At t3, the reactive power output reaches the reference value in (t2 and t3 are not in particular order and need to be based on the actual input power command.) p satisfy Satisfy the unit's maximum ramp rate constraint R p ≤R Pm . Unit reactive power ramp rate And satisfy R Q ≤R Qm . R Pm and R Qm are the maximum ramp rates of active power and reactive power of wind turbine 1, respectively. Reactive load is continuously cut off from t0 to t3, dropping to zero at t3. This gradual reduction in reactive load prevents excessive reactive power output from energy storage system 2, which could result in a drop in output voltage and a startup failure of wind turbine 1.

[0056] In the preferred embodiment, during the period from t0 to t3, K1 is closed at t0 to connect to wind turbine 1, and the reactive ramp is completed at t3, and the reactive output of wind turbine 1 reaches the reference value. Completely cut off the reactive load; in which, the reactive load from t1 to t3 is finally reduced to 0 after being cut off n times:

[0057]

[0058] The load amount for each cut-out.

[0059] Step 6: When the active power output of wind turbine 1 reaches After that, the remaining active load is put into When the output of wind turbine 1 fluctuates and the load fluctuates, the energy storage system 2 can automatically smooth the wind power and compensate for the load.

[0060] By adopting the above technical solution, the reactive power control method of the present invention reduces the reactive power absorbed by energy storage by regulating the reactive power of the load and the wind turbine, effectively enabling the operation of wind turbines remote from the busbar. Furthermore, when the wind turbines are started, the energy storage system automatically smooths out fluctuations in wind farm output while also compensating for load output fluctuations.

[0061] This invention proposes a method and apparatus for dynamic networking and coordinated control of an off-grid wind-energy storage-load system. Dynamic networking of a wind-energy storage-load system refers to the differentiated dynamic networking control process among the wind power generation system, energy storage system, and loads, based on varying operating conditions, during off-grid operation. For example, after a black start of the energy storage system establishes stable voltage and frequency, the wind turbines are started. Dynamic switching and real-time power optimization control are then implemented for the wind turbines and loads operating in the isolated grid, ensuring balanced power supply and demand for the entire system and stable and reliable operation.

[0062] Wind turbine load power coordinated control method: The standby reactive load is put into operation by calculating the reactive power on the wind turbine side, and the reactive load is gradually cut out when the wind turbine is reactively ramping, thereby compensating for the reactive power emitted by the cable on the wind turbine side.

[0063] The present invention's off-grid wind-storage-load system dynamically networks and controls the wind power generation system, energy storage system, and loads based on different operating conditions during off-grid operation. For example, after a black start with energy storage establishes stable voltage and frequency, the wind turbines are started. Dynamic switching and real-time power optimization control are then implemented for the wind, energy storage, and load systems operating in isolated grid conditions, ensuring balanced power supply and demand across the entire system and stable and reliable operation.

[0064] It is understood from common technical knowledge that the present invention may be implemented by other embodiments that do not depart from its spirit or essential features. Therefore, the embodiments disclosed above are, in all respects, merely illustrative and not exclusive. All modifications within the scope of the present invention or equivalent to the scope of the present invention are intended to be encompassed by the present invention.

[0065] It will be understood by those skilled in the art that embodiments of the present invention may be provided as methods, systems, or computer program products. Thus, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0066] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowcharts and / or block diagrams, as well as combinations of processes and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowcharts and / or block diagrams. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0067] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0068] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0069] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered by the scope of protection of the claims of the present invention.

Claims

1. A control method for a dynamic networking coordination control device of an off-grid wind-load storage system, characterized in that: The off-grid wind-load storage system dynamic networking coordination control device comprises: a wind turbine (1), an energy storage system (2), a box-type transformer T1, a cable (3), a box-type transformer T2, a reactive standby load P1, an active load P2 and a high-voltage bus (4); the output end of the wind turbine (1) is divided into two paths, one path is connected to the input end of the box-type transformer T1 through a circuit breaker K1, and the other path is connected to the input end of the box-type transformer T1 through a wind turbine converter (11); the output end of the box-type transformer T1 is connected to one end of the circuit breaker K2 through a cable (3), and the other end of the circuit breaker K2 is connected to the high-voltage bus (4); the energy storage system (2) is connected to the high-voltage bus (4) through the box-type transformer T2; the reactive standby load P1 and the active load P2 are both connected to the high-voltage bus (4); The control method includes: Disconnect circuit breaker K2, start the energy storage system (2), and put active load into operation. Operation, forming an off-grid load storage system; When the output voltage and power of the off-grid load storage system are stable and operating normally, close the circuit breaker K2 and connect the wind turbine (1); Measure the reactive power generated by the wind turbine and input an equal reactive load from the reactive standby load P1; The wind turbine converter (11) of the wind turbine (1) starts to modulate, and a stable DC bus voltage is established between the rectifier and the inverter of the wind turbine converter (11). The voltage starts to synchronize with the energy storage side voltage. When the phase, amplitude and frequency deviations reach the set range, the grid-connected circuit breaker K1 is closed; The fan (1) starts to generate active power and reactive power and ramps up at a constant speed; before the reactive power output of the fan (1) reaches a set value, the reactive load input from the reactive standby load P1 is gradually reduced; When the active power output of the fan (1) reaches the set value, the remaining active load is put into operation. When the reactive power output reaches the set value, the reactive load put into the reactive standby load P1 is completely cut out. The total capacity of the active load P1 is 2. The control method according to claim 1, characterized in that: Active load The size is smaller than the total capacity of the energy storage system (2).

3. The control method according to claim 1, characterized in that: At t1, the fan (1) starts to generate active power and reactive power and ramps up at a constant speed; at t2, the active power output of the fan (1) reaches the reference value. At t3, the reactive power output of the fan (1) reaches the reference value .

4. The control method according to claim 3, characterized in that: Before the reactive power output of the fan (1) reaches a set value, the reactive load input from the reactive standby load P1 is gradually reduced, and the reactive load is cut out n times.

5. The control method according to claim 1, characterized in that: The energy storage system (2) uses a plurality of energy storage devices (21) connected in parallel.

6. The control method according to claim 5, characterized in that: The energy storage system (2) adopts virtual synchronous control, which is divided into active frequency control and reactive voltage control, which are used to simulate the speed regulation and excitation system of the synchronous generator respectively.

7. The control method according to claim 5, characterized in that: The energy storage system (2) is a voltage source type energy storage system.

8. The control method according to claim 1, characterized in that: The off-grid wind-load storage system dynamic networking coordination control device further comprises a load power control device; the load power control device is used to measure the active power and reactive power generated by the wind turbine (1); and to control the switching of the reactive standby load P1 and the active load P2.

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