A flexible coordinated control device and method for offshore wind power with dual busbars and live-loop control.

Abstract

This invention relates to a flexible coordinated control device and method for dual-busbar live-loop operation in offshore wind power, comprising a loop-closing branch, a bus tie switch, a first electrical mechanism, and a second electrical mechanism. The first electrical mechanism, the second electrical mechanism, and the bus tie switch are all located on the loop-closing branch, with the bus tie switch positioned between the first and second electrical mechanisms. The first electrical mechanism includes multiple sets of first generator components and a first reactive power generator. The second electrical mechanism includes multiple sets of second generator components and a second reactive power generator. A coordination controller is also included, comprising a voltage phase compensation loop and a voltage amplitude compensation loop. Both the voltage phase compensation loop and the voltage amplitude compensation loop are connected to the bus tie switch, the first generator components, the first reactive power generator, the second generator components, and the second reactive power generator. The device compensates online for the effective voltage difference and phase angle difference at the loop-closing point of the offshore wind power system, enabling the system to reach optimal loop-closing conditions and effectively reducing the impact of loop-closing operations on the system.

Description

Technical Field

[0001] This invention relates to the field of offshore wind power technology, and in particular to a flexible coordinated control device and method for offshore wind power dual-busbar live-line control. Background Technology

[0002] Currently, my country's power system is mostly designed with a closed loop and operates with an open loop. The closed loop design is used to improve operational flexibility and power supply reliability, while the open loop operation is used to limit short-circuit fault current and prevent circuit breakers from exceeding their breaking capacity and exploding. It also controls the scope of the fault and avoids the power outage from spreading. Furthermore, the multi-source connection method with converters at the bus end of renewable energy systems has been widely used. For offshore wind power systems, closed loops can be used to ensure that wind turbines do not disconnect from the grid, which not only meets the requirements of system maintenance but also maximizes the utilization of wind resources.

[0003] However, unlike traditional generators, wind power, as a new energy source, has a weak overall system inertia, high harmonic content, and poor anti-interference ability when integrated into the grid due to the large number of inverter and rectifier devices it contains. Abnormal fluctuations in power flow can easily cause system oscillations. In order to meet the requirements of grid operation, wind power generation busbars generally need to be equipped with grounding transformers, reactive power compensators, and other power devices. Compared with conventional power systems, the operating conditions of systems powered by new energy sources using power electronic converters are more complex. The loop current generated in the line during loop closing may cause risks such as circuit breaker tripping, line overload, and malfunction of overcurrent protection or instantaneous overcurrent protection. In particular, offshore wind power systems need to ensure that switching is carried out under conditions of minimal changes in power flow distribution in order to ensure the safe and stable operation of the system and the maximum utilization of wind resources.

[0004] Therefore, most existing loop closing methods rely on manual adjustment of the voltage and phase on both sides of the closing point, combined with the experience of the staff, which introduces significant random risks in actual operation. There are two main types: the first is based on the characteristics of the distribution network loop closing, employing a combined control method of distributed power sources and energy storage. This involves offline calculation of the voltage, active and reactive loads of each node in the distribution network, as well as the active and reactive power of distributed power sources, to implement adjustments and suppress loop closing fluctuations. The second type involves setting up voltage and phase compensation devices at the closing point to achieve voltage and phase compensation.

[0005] However, offline calculations require the use of a large amount of measurement data, especially for offshore wind power systems, where current, voltage, and power vary with wind resources. Furthermore, offline calculations and manual circuit breaking involve significant uncertainties and safety risks associated with circuit breaking. Additionally, adding extra phase-shifting transformers, converters, and similar power flow controllers to the system increases the investment in wind power generation systems and affects the stability of the system during steady-state operation. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to overcome the defects of uncertainty and safety hazards in the offline loop closing of offshore wind power systems in the prior art, thereby providing a flexible coordinated control device and method for offshore wind power dual-bus active loop closing.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A flexible coordinated control device for offshore wind power with dual busbars and live loop connection includes: a loop connection branch, a bus tie switch, a first electrical mechanism, and a second electrical mechanism.

[0009] The first electrical mechanism, the second electrical mechanism, and the bus tie switch are all located on the closed loop branch, and the bus tie switch is located between the first electrical mechanism and the second electrical mechanism;

[0010] The first electrical mechanism includes multiple sets of first power generation components and a first reactive power generator; the second electrical mechanism includes multiple sets of second power generation components and a second reactive power generator.

[0011] It also includes a coordination controller, which comprises a voltage phase compensation loop and a voltage amplitude compensation loop.

[0012] The voltage phase compensation loop and the voltage amplitude compensation loop are both connected to the two ends of the bus tie switch to obtain the corresponding voltage phase angle difference and effective voltage difference; and based on the voltage phase angle difference and effective voltage difference, the first coordinated control power reference value of the active power of the first power generation component and the second power generation component and the second coordinated power reference value of the first reactive power generator and the second reactive power generator are obtained.

[0013] The voltage phase compensation loop and the voltage amplitude compensation loop are both connected to the first power generation component and the second power generation component, and the active power coordination coefficient of the first power generation component and the second power generation component is corrected based on the first coordinated control power reference value.

[0014] The voltage phase compensation loop and the voltage amplitude compensation loop are both connected to the first reactive power generator and the second reactive power generator, and the reactive power coordination coefficient of the first reactive power generator and the second reactive power generator is corrected based on the second coordinated power reference value.

[0015] The bus tie switch is connected to the voltage phase compensation loop and the voltage amplitude compensation loop, and is used to receive the loop closing signal.

[0016] Preferably, the voltage phase compensation loop includes an integrated first calculation unit, a first comparison unit, and a first integration control unit.

[0017] Preferably, the voltage amplitude compensation loop includes an integrated second calculation unit, a second comparison unit, and a second integral control unit.

[0018] Preferably, the coordination controller further includes a signal control module, which includes a transmitting end and a receiving end.

[0019] The receiving end is connected to the voltage phase compensation loop and the voltage amplitude compensation loop, and the transmitting end is connected to the bus tie switch, the first power generation component, the first reactive power generator, the second power generation component, and the second reactive power generator.

[0020] Preferably, the coordination controller further includes a pre-control unit connected to the receiving end.

[0021] Preferably, the first power generation component includes a first wind turbine and a first converter, one end of the first converter is connected to the first wind turbine, the other end is connected to the loop branch, and the coordination controller is signal-connected to the first converter;

[0022] The second power generation component includes a second wind turbine and a second converter. One end of the second converter is connected to the second wind turbine, and the other end is connected to the loop branch. The coordination controller is signal-connected to the second converter.

[0023] Preferably, it further includes a first busbar assembly and a second busbar assembly, the first busbar assembly and the second busbar assembly being respectively connected to the loop-connected branches on both sides of the bus tie switch; and the first electrical mechanism and the second electrical mechanism supply power to the first busbar assembly and the second busbar assembly.

[0024] Preferably, the first busbar assembly includes a first busbar, a first data collector, and a first main transformer. The first busbar is connected to the loop branch. The first data collector and the first main transformer are both located on the first busbar, and the first data collector is signal-connected to the coordination controller.

[0025] The second busbar assembly includes a second busbar, a second data acquisition unit, and a second main transformer. The second busbar is connected to the loop branch. The second data acquisition unit and the second main transformer are both located on the second busbar, and the second data acquisition unit is signal-connected to the controller.

[0026] Preferably, it further includes a transmission circuit, which is connected to the end of the first busbar and the second busbar away from the loop branch, respectively.

[0027] A flexible coordinated control method for dual-busbar offshore wind power with live power supply, employing any of the flexible coordinated control devices described above, includes the following steps:

[0028] Step 1: Obtain the voltage phase angle difference across the bus tie switch through the voltage phase compensation loop, and denote the voltage phase angle difference as Δθ; obtain the effective voltage difference across the bus tie switch through the voltage amplitude compensation loop, and denote the effective voltage difference as ΔU.

[0029] Step 2: Based on the pre-loop closing signal, the active power of the first power generation component and the second power generation component are recorded during the pre-loop closing, and the reactive power of the first reactive power generator and the second reactive power generator are recorded during the pre-loop closing; at the same time, the loop closing coordination control mode is entered.

[0030] Step 3: The voltage phase compensation loop obtains the phase angle comparison difference through Δθ, and records the phase angle comparison difference as Δθerr. It then obtains the active power coordination coefficient of the first power generation component and the second power generation component through Δθerr, and records the active power coordination coefficient as Kp.

[0031] Step 4: Obtain the first coordinated control power reference value using the active power and Kp recorded by the first power generation component and the second power generation component during pre-loop closing in Step 2; and apply the first coordinated control power reference value to the first power generation component and the second power generation component.

[0032] Step 5: The voltage amplitude compensation loop obtains the amplitude comparison difference through ΔU, and records the amplitude comparison difference as ΔUerr. It also obtains the reactive power coordination coefficient between the first reactive power generator and the second reactive power generator through ΔUerr, and records the reactive power coordination coefficient as Kq.

[0033] Step 6: Obtain the second coordinated control power reference value by using the reactive power and Kq recorded by the first reactive power generator and the second reactive power generator during the pre-loop closing in Step 2, and apply the second coordinated control power reference value to the first reactive power generator and the second reactive power generator.

[0034] Step 7: The coordination controller corrects Kp and Kq so that ΔU and Δθ tend to 0; and when ΔU and Δθ are both equal to 0, the coordination controller sends a loop closing command to the bus tie switch, the bus tie switch is closed, and the coordination controller completes the coordination control.

[0035] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0036] The aforementioned technical solution provides a flexible coordinated control device and method for offshore wind power dual-busbar active loop closure. Through online compensation of voltage phase and voltage amplitude in the coordinated controller, it compensates for the effective voltage difference and phase angle difference at the loop closure point of the offshore wind power system, thereby achieving optimal loop closure conditions. This effectively reduces the impact of loop closure operations on the system and avoids the uncertainties of manual, experience-based loop closure. Simultaneously, online compensation of the effective voltage difference and phase angle difference avoids the uncertainties arising from variations in the effective voltage difference and voltage phase angle difference during wind power system loop closure due to changes in wind resources, making the offshore wind power system loop closure process safer and more reliable. Furthermore, this coordinated controller can directly cooperate with existing equipment in the offshore wind power system for loop closure operations, ensuring the overall steady-state operation of the original system while reducing system design costs. Attached Figure Description

[0037] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0038] Figure 1 This is a schematic diagram of the overall structure of a flexible coordinated control device for offshore wind power with dual busbars and live-loop connection provided in one embodiment of the present invention.

[0039] Figure 2 for Figure 1 The diagram shows the overall structure of the flexible coordination control device.

[0040] Figure 3 for Figure 1 The diagram shows the control flow of the flexible coordination control device.

[0041] Figure 4 A power simulation diagram for the first bus without a coordination control device.

[0042] Figure 5 The current simulation diagram is for the first busbar without a coordination control device.

[0043] Figure 6 A power simulation diagram of setting up a coordination control device for the first bus.

[0044] Figure 7 Current simulation diagram of setting up a coordination control device for the first busbar.

[0045] Figure 8 A simulation diagram of the voltage across the bus tie switch after setting up the coordination control device.

[0046] Explanation of reference numerals in the attached figures:

[0047] 1. Loop branch; 11. Bus tie switch; 12. First generator assembly; 121. First wind turbine; 122. First converter; 123. First reactive power generator; 13. Second generator assembly; 131. Second wind turbine; 132. Second converter; 133. Second reactive power generator; 14. First busbar; 141. First data acquisition unit; 142. First main transformer; 15. Second busbar; 151. Second data acquisition unit; 152. Second main transformer; 16. Transmission line;

[0048] 2. Coordination Controller; 21. Voltage Phase Compensation Loop; 211. First Calculation Unit; 212. First Comparison Unit; 213. First Integral Control Unit; 22. Voltage Amplitude Compensation Loop; 221. Second Calculation Unit; 222. Second Comparison Unit; 223. Second Integral Control Unit; 23. Signal Control Module; 24. Pre-Control Unit. Detailed Implementation

[0049] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0050] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0051] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0052] Based on the closed-loop power impact formula, it can be seen that the magnitude of the closed-loop impact current is related to the effective voltage difference and voltage phase angle difference across the bus tie switch during closed-loop operation; specifically, the closed-loop power impact formula is as follows:

[0053]

[0054] in,

[0055] E m This represents the voltage difference across the bus tie switch when the loop is closed.

[0056] δ is the initial phase angle of the closed loop corresponding to the voltage.

[0057] R and L are the equivalent resistance and inductance of the closed-loop circuit.

[0058] T a The time constant (T) a =L / R);

[0059] Meanwhile, based on the characteristics of the 220kV main transformer, the voltage expression between the two busbars is:

[0060]

[0061] in,

[0062] P1 and Q1 represent the active and reactive power outputs of the wind turbines in section I of the busbar.

[0063] P2 and Q2 represent the active and reactive power outputs of the fan in section II of the busbar.

[0064] X1 and X2 are the equivalent inductive reactances of main transformer 1 and main transformer 2;

[0065] Therefore, it can be seen that the real part of the voltage components of the two main transformers on the double busbar is mainly related to the reactive power output, while the imaginary part is mainly related to the active power output. That is, by controlling the active and reactive power flowing through the two main transformers on the double busbar, the effective voltage difference and voltage phase angle difference across the bus tie switch can be made to approach 0, thus suppressing the loop impact.

[0066] Therefore, embodiments of the present invention provide a flexible coordinated control device for offshore wind power with dual busbars and live loop connection, such as... Figure 1 and Figure 2 The system includes: a closed-loop branch 1, a bus tie switch 11, a first electrical mechanism, and a second electrical mechanism. The first electrical mechanism, the second electrical mechanism, and the bus tie switch 11 are all located on the closed-loop branch 1, with the bus tie switch 11 positioned between the first and second electrical mechanisms to control the connection and disconnection between them. Specifically, the first electrical mechanism includes multiple sets of first power generation components 12 and first reactive power generators 123, and the second electrical mechanism includes multiple sets of second power generation components 13 and second reactive power generators 133. Both the first power generation components 12 and the second power generation components 13 are used for converter power generation, and both the first reactive power generators 123 and the second reactive power generators 133 are used for reactive power compensation. The system also includes a coordination controller 2, which includes a voltage phase compensation loop 21 and a voltage amplitude compensation loop 22. The voltage phase compensation loop 21 and the voltage amplitude compensation loop 22 are used to compensate for the voltage amplitude difference and voltage phase angle difference at the closed-loop point of the system online, thereby achieving the optimal closed-loop state of the system and suppressing the reactive power generated by the closed-loop operation. The voltage phase compensation loop 21 and voltage amplitude compensation loop 22 are both connected to both ends of the bus tie switch 11 to obtain the corresponding voltage phase angle difference and effective voltage difference; and based on the voltage phase angle difference and effective voltage difference, the first coordinated control power reference value of the first power generation component 12 and the second power generation component 13 and the second coordinated power reference value of the first reactive power generator 123 and the second reactive power generator 133 are obtained; the voltage phase compensation loop 21 and voltage amplitude compensation loop 22 are both connected to the first power generation component 12 and the second power generation component 13. The system connects and corrects the active power coordination coefficients of the first power generation component 12 and the second power generation component 13 based on the first coordinated control power reference value; the voltage phase compensation loop 21 and the voltage amplitude compensation loop 22 are both connected to the first reactive power generator 123 and the second reactive power generator 133, and correct the reactive power coordination coefficients of the first reactive power generator 123 and the second reactive power generator 133 based on the second coordinated power reference value; the bus tie switch 11 is connected to the voltage phase compensation loop 21 and the voltage amplitude compensation loop 22, and is used to receive the loop closing signal.

[0067] The voltage phase compensation loop 21 and voltage amplitude compensation loop 22 in the coordinated controller 2 provide online compensation for the effective voltage difference and phase angle difference at the loop closing point of the offshore wind power system, thereby enabling the system to reach the optimal loop closing conditions. This effectively reduces the impact of loop closing operations on the system and avoids the uncertainty of manual loop closing based on experience. At the same time, online compensation for effective voltage difference and phase angle difference also avoids the uncertainty caused by the changes in effective voltage difference and voltage phase angle difference during loop closing of the wind power system with wind resource variations, making the loop closing process of the offshore wind power system safer and more reliable. In addition, the coordinated controller can directly cooperate with existing equipment in the offshore wind power system to perform loop closing operations, ensuring the overall steady-state operation of the original system while reducing the cost of system design.

[0068] like Figure 2 As shown, the voltage phase compensation loop 21 includes an integrated first calculation unit 211, a first comparison unit 212, and a first integral control unit 213. The first calculation unit 211 is used to calculate the voltage phase angle difference across the bus tie switch 11 when the system is closed. The first comparison unit 212 obtains the phase angle comparison difference based on the voltage phase angle difference obtained by the first calculation unit 211, and obtains the active power coordination coefficient between the first motor in the first power generation component 12 and the second motor in the second power generation component 13 by combining the phase angle comparison difference obtained by the first comparison unit 212 with the first integral control unit 213. In addition, the first calculation unit 211 includes a chip with calculation function, the first comparison unit 212 includes a chip with a fixed comparison value, and the first integral control unit 213 is a proportional-integral controller in the prior art.

[0069] Specifically, the voltage amplitude compensation loop 22 includes an integrated second calculation unit 221, a second comparison unit 222, and a second integral control unit 223. The second calculation unit 221 calculates the effective voltage difference across the bus tie switch 11 when the system loop is closed. The second comparison unit 222 obtains the amplitude comparison difference based on the effective voltage difference obtained by the second calculation unit 221, and uses the second integral control unit 223 to combine the amplitude comparison difference obtained by the second comparison unit 222 to obtain the reactive power coordination coefficient of the first reactive power generator 123 and the second reactive power generator 133. Furthermore, the second calculation unit 221 includes a chip with calculation functions, the second comparison unit 222 includes a chip with a fixed comparison value, and the second integral control unit 223 is a proportional-integral controller (PIC) as used in the prior art.

[0070] Furthermore, the comparison values ​​set for both the first comparison unit 212 and the second comparison unit 222 are 0.

[0071] Specifically, the coordination controller 2 also includes a signal control module 23, which is used to control the transmission of signals when the system is closed in a loop. Specifically, the signal control module 23 includes a transmitting end and a receiving end, and the receiving end is connected to the voltage phase compensation loop 21 and the voltage auxiliary compensation loop 22, while the transmitting end is connected to the bus tie switch 11, the first power generation component 12, the first reactive power generator 123, the second power generation component 13, and the second reactive power generator 133.

[0072] Preferably, to facilitate the pre-loop closing signal processing of the coordination controller 2, the coordination controller 2 further includes a pre-control unit 24; specifically, the pre-control unit 24 is connected to the receiving end of the signal control module 23; when the signal control module 23 receives the pre-loop closing signal sent by the pre-control unit 24, the signal control module 23 will transfer the pre-loop closing signal and send it to the first reactive power generator 123 and several first fans 121 in the first electrical mechanism, and the second reactive power generator 133 and several second fans 131 in the second electrical mechanism.

[0073] like Figure 1 As shown, the first power generation component 12 includes a first wind turbine 121 and a first converter 122. One end of the first converter 122 is connected to the first wind turbine 121, and the other end is connected to the loop-closing branch 1. The signal control module 23 of the coordination controller 2 is connected to the first converter 122. The first wind turbine 121 is used to generate electricity. One end of the first converter 122 is connected to the first wind turbine 121 and is used to perform voltage and frequency regulation on the electricity generated by the first wind turbine 121. The other end of the first converter 122 is connected to the signal control module 23 of the coordination controller 2 and is used to receive the loop-closing control signal from the signal control module 23 or the pre-loop-closing signal transferred by the signal control module 23.

[0074] Specifically, the second power generation component 13 includes a second wind turbine 131 and a second converter 132. One end of the second converter 132 is connected to the second wind turbine 131, and the other end is connected to the loop-closing branch 1. The signal control module 23 of the coordination controller 2 is connected to the second converter 132. The first wind turbine 121 is used to generate electricity. One end of the first converter 122 is connected to the first wind turbine 121 and is used to perform voltage and frequency regulation on the electricity generated by the first wind turbine 121. The other end of the first converter 122 is connected to the signal control module 23 of the coordination controller 2 and is used to receive the loop-closing control signal from the signal control module 23 or the pre-loop-closing signal transferred by the signal control module 23.

[0075] Specifically, the wind power system corresponding to the device also includes a first busbar assembly and a second busbar assembly; wherein, the first busbar assembly and the second busbar assembly are respectively connected to the loop branch 1 on both sides of the bus tie switch 11, and both the first busbar assembly and the second busbar assembly are used for power transmission and transformation; and the first electrical mechanism and the second electrical mechanism are used to supply power to the first busbar assembly and the second busbar assembly.

[0076] Specifically, the first busbar assembly includes a first busbar 14, a first data acquisition unit 141, and a first main transformer 142; the first busbar 14 is connected to the loop branch 1, and the first busbar 14 includes a high-voltage transmission line for transmitting the power generated by the loop branch 1; the first data acquisition unit 141 and the first main transformer 142 are both installed on the first busbar 14, the first data acquisition unit 141 includes a voltage or current acquisition device for acquiring power signals on the first busbar 14, the first main transformer 142 is used to change the AC voltage on the first busbar 14, and the first data acquisition unit 141 is signal-connected to the coordination controller 2 for transmitting the acquired power signals to the coordination controller 2 for further processing.

[0077] Specifically, the second busbar assembly includes a second busbar 15, a second data acquisition unit 151, and a second main transformer 152. The second busbar 15 is connected to the loop branch 1 and includes a high-voltage transmission line for transmitting the power generated by the loop branch 1. The second data acquisition unit 151 and the second main transformer 152 are both installed on the second busbar 15. The second data acquisition unit 151 includes a voltage or current acquisition device for acquiring power signals on the second busbar 15. The second main transformer 152 is used to change the AC voltage on the second busbar 15. The second data acquisition unit 151 is connected to the controller signal for transmitting the acquired power signals to the coordination controller 2 for further processing. The first main transformer 142 and the second main transformer 152 are both the main transformers mentioned above.

[0078] Preferably, the device further includes a transmission circuit 16, which is connected to the ends of the first busbar 14 and the second busbar 15 away from the loop branch 1, respectively; the transmission circuit 16 is used to integrate and utilize the power transmitted through the first busbar assembly and the second busbar assembly.

[0079] It is worth noting that the signal transmission involved in the above schemes can be carried out in wired or wireless transmission methods according to actual needs; however, in this embodiment, fiber optic wired transmission is preferred for ease of operation and debugging.

[0080] A flexible coordinated control method for dual-busbar offshore wind power systems, employing the aforementioned flexible coordinated control device, such as... Figure 3 The steps shown are as follows:

[0081] Step 1: The first collector 141 and the second collector 151 acquire power information located on both sides of the bus tie switch 11, respectively, and transmit the acquired power signals to the coordination controller 2 via wired or wireless means. Specifically, the voltage phase compensation loop 21 in the coordination controller 2 acquires the voltage phase angle difference across the bus tie switch 11 based on the power information acquired by the first collector 141 and the second collector 151, and records the voltage phase angle difference as Δθ; the voltage amplitude compensation loop 22 in the coordination controller 2 acquires the effective voltage difference across the bus tie switch 11 based on the power information acquired by the first collector 141 and the second collector 151, and records the effective voltage difference as ΔU.

[0082] Step two: The pre-loop control unit 24 sends a pre-loop closing signal to the signal control module 23, and then the signal control module 23 transfers the pre-loop closing signal to the first reactive power generator 123, the second reactive power generator 133, several first wind turbines 121, and several second wind turbines 131 for pre-loop closing; the first converter corresponding to the first wind turbine 121 and the second converter corresponding to the second wind turbine 131 record the active power at the time of pre-loop closing, and record the pre-loop closed active power as P1, P2, P3...Pn; the first reactive power generator 123 and the second reactive power generator 133 record the reactive power at the time of pre-loop closing, and record the pre-loop closed reactive power as Q1 and Q2. Further, the loop closing coordination control mode is entered.

[0083] Step 3: The phase angle comparison difference is generated by comparing Δθ with the first comparison module in the voltage phase compensation loop 21, and the phase angle comparison difference is recorded as Δθerr. The first integral controller processes Δθerr to obtain the active power coordination coefficient of several wind turbines and several second wind turbines 131, and the active power coordination coefficient is recorded as Kp. At the same time, Kp is transmitted to the first converter 122 corresponding to the first wind turbine 121 and the second converter corresponding to the second wind turbine 131.

[0084] Step four: Multiply the active power recorded in the first converter 122 and the second converter 132 during pre-loop closing by Kp to obtain the first coordinated control power reference value for the first wind turbine 121 and the second wind turbine 131; further, apply the obtained first coordinated control power reference value to the corresponding first wind turbine 121 and the second wind turbine 131, and record the first coordinated control power reference value as Pref-1, Pref-2, Pref-3...Pref-n;

[0085] Step 5: The amplitude comparison difference is generated by comparing ΔU with the second comparison module in the voltage amplitude compensation loop 22, and the amplitude comparison difference is recorded as ΔUerr. The first integral controller processes ΔUerr to obtain the reactive power coordination coefficient of the first reactive power generator 123 and the second reactive power generator 133, and the reactive power coordination coefficient is recorded as Kq. At the same time, Kq is transmitted to the reactive power controllers of the first reactive power generator 123 and the second reactive power generator 133.

[0086] Step 6: Using the reactive power and Kq recorded by the first reactive power generator 123 and the second reactive power generator 133 during the pre-loop closing in Step 2, obtain the second coordinated control power reference value of the first reactive power generator 123 and the second reactive power generator. Further, apply the second coordinated control power reference value to the first reactive power generator 123 and the second reactive power generator 133, and record the second coordinated control power reference value as SVGref-1 and SVGref-2.

[0087] Step seven: Kp and Kq are corrected by the coordination controller 2 so that ΔU and Δθ tend to 0. Specifically, the magnitude of the voltage phase angle difference is related to the active power difference between the first wind turbines 121 and the second wind turbines 131. Therefore, an active power coordination coefficient is generated here by the voltage phase angle difference and the first integral controller. The generated active power coordination coefficient is transmitted through optical fiber to the first converter 122 corresponding to the first wind turbines 121 and the second converter 132 corresponding to the second wind turbines 131, thereby generating a first coordinated control power reference value. The generated first coordinated control power reference value is then applied to the first converters 122 and 132. In converter 122 and several second converters 132, the active power output of each converter 122 and the second converter 132 is adjusted to change the voltage phase angle difference, thus forming a closed-loop control. Furthermore, the active power coordination coefficient generated by the voltage phase compensation loop 21 through the first converter 122 and the second converter 132 can change the active power output, thereby changing the voltage phase angle difference. This voltage phase angle difference then generates a new active power coordination coefficient. Because it is an online adjustment, the voltage phase angle difference is constantly changing, and therefore the active power coordination coefficient is also constantly changing, until the voltage phase angle difference changes to 0; and the effective voltage difference... The reactive power difference between the first reactive power generator 123 and the second reactive power generator 133 is relevant. Therefore, a reactive power coordination coefficient is generated here through the effective voltage difference and the second integral controller. This generated reactive power coordination coefficient is transmitted via optical fiber to the power control loop of the first reactive power generator 123 and the second reactive power generator 133, thereby generating a second coordinated control power reference value. This second coordinated control power reference value is then applied to the first reactive power generator 123 and the second reactive power generator 133, and the reactive power output is adjusted using the first reactive power generator 123 and the second reactive power generator 133, thereby changing the effective voltage difference. Thus, a closed-loop control is formed. Furthermore, the first reactive power generator 123 and the second reactive power generator 133 change the reactive power output through the reactive power coordination coefficient generated by the voltage amplitude compensation loop 22, thereby changing the effective voltage difference. Then, the effective voltage difference generates a new reactive power coordination coefficient. Since it is an online adjustment, the effective voltage difference will keep changing, and thus the reactive power coordination coefficient will also keep changing until the effective voltage difference changes to 0. When ΔU and Δθ are both equal to 0, the coordination controller 2 sends a loop closing command to the bus tie switch 11, the bus tie switch 11 closes, and the coordination controller 2 completes the coordination control.

[0088] like Figure 4 The diagram shows the power of the first bus 14 without the coordination controller 2. Its active and reactive power oscillate during the 8s loop closure. Figure 5The figure shows the current of the first bus 14 without the coordination controller 2, and the current fluctuates and the active power has an over-adjustment of about 60%. The power reaches a steady state after about 750ms.

[0089] like Figure 6 As shown, after the 2s coordinating controller 2 intervenes, the active power supply of the first bus 14 experiences a slight oscillation, with an overshoot of approximately 0.0003%; Figure 7 As shown, the current shows no significant fluctuation; as Figure 8 As shown, the voltage across the bus tie switch 11 drops to 0 kV after the intervention of the coordinating controller 2 (the larger fluctuation is the instantaneous value, and the smoother fluctuation is the effective value). Simulation results show that the coordinating controller 2 can effectively compensate for the effective voltage difference and voltage phase angle difference at the loop closing point online, thereby effectively suppressing the generation of loop oscillations.

[0090] The above embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention shall fall within the scope of protection claimed by the present invention.

Claims

1. A flexible coordinated control device for offshore wind power with dual busbars and live loop control, characterized in that, include: The loop branch circuit, bus tie switch, first electrical mechanism and second electrical mechanism, The first electrical mechanism, the second electrical mechanism, and the bus tie switch are all located on the closed loop branch, and the bus tie switch is located between the first electrical mechanism and the second electrical mechanism; The first electrical mechanism includes multiple sets of first power generation components and a first reactive power generator; the second electrical mechanism includes multiple sets of second power generation components and a second reactive power generator. It also includes a coordination controller, which comprises a voltage phase compensation loop and a voltage amplitude compensation loop. The voltage phase compensation loop and the voltage amplitude compensation loop are both connected to the two ends of the bus tie switch to obtain the corresponding voltage phase angle difference and effective voltage difference; and based on the voltage phase angle difference and effective voltage difference, the first coordinated control power reference value of the active power of the first power generation component and the second power generation component and the second coordinated power reference value of the first reactive power generator and the second reactive power generator are obtained. The voltage phase compensation loop and the voltage amplitude compensation loop are both connected to the first power generation component and the second power generation component, and the active power coordination coefficient of the first power generation component and the second power generation component is corrected based on the first coordinated control power reference value. The voltage phase compensation loop and the voltage amplitude compensation loop are both connected to the first reactive power generator and the second reactive power generator, and the reactive power coordination coefficient of the first reactive power generator and the second reactive power generator is corrected based on the second coordinated power reference value. The bus tie switch is connected to the voltage phase compensation loop and the voltage amplitude compensation loop, and is used to receive the loop closing signal.

2. The flexible coordination control device according to claim 1, characterized in that, The voltage phase compensation loop includes an integrated first calculation unit, a first comparison unit, and a first integration control unit.

3. The flexible coordination control device according to claim 1, characterized in that, The voltage amplitude compensation loop includes an integrated second calculation unit, a second comparison unit, and a second integral control unit.

4. The flexible coordination control device according to claim 1, characterized in that, The coordination controller further includes a signal control module, which comprises a transmitting end and a receiving end. The receiving end is connected to the voltage phase compensation loop and the voltage amplitude compensation loop, and the transmitting end is connected to the bus tie switch, the first power generation component, the first reactive power generator, the second power generation component, and the second reactive power generator.

5. The flexible coordination control device according to claim 4, characterized in that, The coordination controller also includes a pre-control unit, which is connected to the receiving end.

6. The flexible coordination control device according to claim 1, characterized in that, The first power generation component includes a first wind turbine and a first converter. One end of the first converter is connected to the first wind turbine, and the other end is connected to the loop branch. The coordination controller is signal-connected to the first converter. The second power generation component includes a second wind turbine and a second converter. One end of the second converter is connected to the second wind turbine, and the other end is connected to the loop branch. The coordination controller is signal-connected to the second converter.

7. The flexible coordination control device according to claim 1, characterized in that, It also includes a first busbar assembly and a second busbar assembly, the first busbar assembly and the second busbar assembly being respectively connected to the loop branch on both sides of the bus tie switch; and the first electrical mechanism and the second electrical mechanism supply power to the first busbar assembly and the second busbar assembly.

8. The flexible coordination control device according to claim 7, characterized in that, The first busbar assembly includes a first busbar, a first data collector, and a first main transformer. The first busbar is connected to the loop branch. The first data collector and the first main transformer are both installed on the first busbar, and the first data collector is signal-connected to the coordination controller. The second busbar assembly includes a second busbar, a second data acquisition unit, and a second main transformer. The second busbar is connected to the loop branch. The second data acquisition unit and the second main transformer are both located on the second busbar, and the second data acquisition unit is signal-connected to the controller.

9. The flexible coordination control device according to claim 8, characterized in that, It also includes a transmission circuit, which is connected to the end of the first busbar and the second busbar away from the loop branch, respectively.

10. A flexible coordinated control method for dual-busbar offshore wind power with live source loop, comprising using the flexible coordinated control device described in any one of claims 1-9, characterized in that, Includes the following steps, Step 1: Obtain the voltage phase angle difference across the bus tie switch through the voltage phase compensation loop, and denote the voltage phase angle difference as Δθ; obtain the effective voltage difference across the bus tie switch through the voltage amplitude compensation loop, and denote the effective voltage difference as ΔU. Step 2: Based on the pre-loop closing signal, the active power of the first power generation component and the second power generation component are recorded during the pre-loop closing, and the reactive power of the first reactive power generator and the second reactive power generator are recorded during the pre-loop closing; at the same time, the loop closing coordination control mode is entered. Step 3: The voltage phase compensation loop obtains the phase angle comparison difference through Δθ, and records the phase angle comparison difference as Δθerr. It then obtains the active power coordination coefficient of the first power generation component and the second power generation component through Δθerr, and records the active power coordination coefficient as Kp. Step 4: Obtain the first coordinated control power reference value using the active power and Kp recorded by the first power generation component and the second power generation component during pre-loop closing in Step 2; and apply the first coordinated control power reference value to the first power generation component and the second power generation component. Step 5: The voltage amplitude compensation loop obtains the amplitude comparison difference through ΔU, and records the amplitude comparison difference as ΔUerr. It also obtains the reactive power coordination coefficient between the first reactive power generator and the second reactive power generator through ΔUerr, and records the reactive power coordination coefficient as Kq. Step 6: Obtain the second coordinated control power reference value by using the reactive power and Kq recorded by the first reactive power generator and the second reactive power generator during the pre-loop closing in Step 2, and apply the second coordinated control power reference value to the first reactive power generator and the second reactive power generator. Step 7: The coordination controller corrects Kp and Kq so that ΔU and Δθ tend to 0; and when ΔU and Δθ are both equal to 0, the coordination controller sends a loop closing command to the bus tie switch, the bus tie switch is closed, and the coordination controller completes the coordination control.

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