Method and apparatus for controlling the transient stability of an integrated wind and thermal power generation system.

Abstract

A method and apparatus for controlling the transient stability of an integrated wind power and thermal power generation system, the method comprising: acquiring the terminal voltage of a dual-fed wind turbine in real time when the integrated wind power and thermal power generation system fails (S1); receiving that the terminal voltage of the dual-fed wind turbine is in a first voltage drop section, reducing the amplitude of the acceleration phase of the synchronous generator during the failure period by increasing the reactive current injection coefficient of the dual-fed wind turbine according to a preset adjustment rule (S2); receiving that the terminal voltage of the dual-fed wind turbine is in a second voltage drop section, reducing the amplitude of the acceleration phase and deceleration phase of the synchronous generator during the failure period by increasing the reactive current injection coefficient of the dual-fed wind turbine according to an adjustment rule (S3); and receiving that the terminal voltage of the dual-fed wind turbine is in a third voltage drop section, reducing the amplitude of the deceleration phase of the synchronous generator during the failure period by decreasing the reactive current injection coefficient of the dual-fed wind turbine according to an adjustment rule (S4).

Description

[Technical Field]

[0001] This invention claims priority to the Chinese patent application filed with the China Patent Administration on 30 July 2024, application number 202411033542.9, and all contents of said application are incorporated herein by reference.

[0002] This application relates to the technical field of integrated wind power and thermal power generation systems, and more particularly to a method and apparatus for controlling the transient stability of an integrated wind power and thermal power generation system. [Background technology]

[0003] In recent years, with the large-scale development of wind power generation, dual-fed wind turbines are gradually complementing synchronous machines and becoming an even more important power generation unit on the generating side of power systems. However, the physical structure and operating principle of dual-fed wind turbines are clearly different from conventional synchronous machines, and their transient characteristics are more complex, flexible, and variable. This can significantly alter the transient behavior of wind power grid-connected systems and potentially lead to new transient stability problems.

[0004] Currently, research on transient problems in grid-connected power systems for dual-fed wind turbines often involves studying the transient stability of specific power systems using numerical simulation methods. Numerical simulation methods consider complex transient models of dual-fed wind turbines that include multiple phases such as normal control, transient control, and hardware protection, and can reproduce the transient processes of each variable in each complex system as accurately as possible and reflect them intuitively. However, there is still a gap in understanding the influence of transient control parameters (e.g., reactive current injection coefficient) on the transient stability of the system.

[0005] Specifically, for example, conventional methods involve obtaining fault analysis parameters for a wind power plant, calculating voltage division parameters at the grid connection point of the wind power plant, creating a reactive injection proportional coefficient test array and a grid connection point voltage test array, calculating the reactive / active current and terminal voltage of the wind power plant, determining the output active power of each test value in the reactive injection proportional coefficient test array, and determining the test value of the reactive injection proportional coefficient corresponding to the maximum output active power as the optimization parameter for the fault ride-through of the wind power plant. The purpose of this method is to improve the transient stability of the wind power plant after fault recovery, but it fails to improve the transient stability during and after the system failure, and furthermore, this method requires processing a large amount of data, resulting in poor control effects, low control efficiency, and low practicality. [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] The embodiments of this application provide a method and apparatus for controlling the transient stability of an integrated wind power and thermal power generation system, thereby improving the control efficiency and practicality of the transient stability of the integrated wind power and thermal power generation system. [Means for solving the problem]

[0007] The embodiments of this application are as follows: To acquire the terminal voltage of a dual-feed wind turbine in real time during a failure of an integrated wind power generation and thermal power generation system, Given that the terminal voltage of the dual-feed wind turbine is in the first voltage drop zone, the amplitude of the acceleration phase of the synchronous generator during the failure period is reduced by increasing the reactive current injection coefficient of the dual-feed wind turbine according to a predetermined adjustment rule. Given that the terminal voltage of the dual-feed wind turbine is in the second voltage drop zone, the adjustment rules apply. Furthermore, by increasing the reactive current injection coefficient of the dual-feed wind turbine, the amplitude of the acceleration phase and the deceleration phase of the synchronous generator during the failure period can be reduced. Receiving that the terminal voltage of the dual-feed wind turbine is in the third voltage drop section, the adjustment rules are followed to reduce the amplitude of the deceleration phase of the synchronous generator during the fault period, including reducing the reactive current injection coefficient of the dual-feed wind turbine. This invention provides a method for controlling the transient stability of an integrated wind power and thermal power generation system.

[0008] In one embodiment, the first voltage drop interval is less than the first limit value, the second voltage drop interval is greater than the second limit value and less than a preset upper voltage value, and the third voltage drop interval is greater than the first limit value and less than the second limit value.

[0009] In one embodiment, the method is: The terminal voltage history and reactive current injection coefficient history of a dual-feed wind turbine in the event of a failure in an integrated wind and thermal power generation system are acquired, and the reactive current value is determined based on the terminal voltage history and reactive current injection coefficient history. The reactive current value is obtained based on the preset maximum capacity of the current transformer and the reactive injection current value, The method further includes determining a first limit value based on the maximum capacity of the current transformer, the reactive injection current value, and the reactive current value.

[0010] In one embodiment, the method is: To acquire the terminal voltage history of a dual-feed wind turbine in the event of a failure in an integrated wind and thermal power generation system, and to determine the limit value of the low-voltage active limiting logic based on the terminal voltage history, The active current value is obtained based on the preset maximum capacity of the current transformer and the limit value of the low-voltage active limiting logic, The method further includes determining a second limit value based on the maximum capacity of the current transformer, the limit value of the low-voltage active limiting logic, and the active current value.

[0011] The embodiments of this application are as follows: A terminal voltage module configured to acquire the terminal voltage of a dual-feed wind turbine in real time during a failure in an integrated wind and thermal power generation system, A first voltage drop section module is configured to reduce the amplitude of the acceleration phase of the synchronous generator during a failure period by increasing the reactive current injection coefficient of the dual-feed wind turbine in accordance with a preset adjustment rule, based on the fact that the terminal voltage of the dual-feed wind turbine is in the first voltage drop section, A second voltage drop section module is configured to reduce the amplitude of the acceleration phase and the deceleration phase of the synchronous generator during a failure period by increasing the reactive current injection coefficient of the dual-feed wind turbine in accordance with adjustment rules, given that the terminal voltage of the dual-feed wind turbine is in the second voltage drop section. The system includes a third voltage drop section module configured to reduce the amplitude of the deceleration phase of the synchronous generator during a failure period by reducing the reactive current injection coefficient of the dual-feed wind turbine in accordance with the adjustment rule, in response to the terminal voltage of the dual-feed wind turbine being in the third voltage drop section, Further provides a control device for the transient stability of integrated wind and thermal power generation systems.

[0012] In one embodiment, the first voltage drop interval is less than the first limit value, the second voltage drop interval is greater than the second limit value and less than a preset upper voltage value, and the third voltage drop interval is greater than the first limit value and less than the second limit value.

[0013] In one embodiment, the apparatus is A reactive current injection module is configured to acquire the terminal voltage history and reactive current injection coefficient history of a dual-feed wind turbine in the event of a failure in an integrated wind power generation and thermal power generation system, and to determine the reactive current injection value based on the terminal voltage history and reactive current injection coefficient history. A reactive current value module configured to acquire a reactive current value based on a preset maximum capacity of a current transformer and the reactive injection current value, The system further comprises a first limit value module configured to determine a first limit value based on the maximum capacity of the current transformer, the reactive injection current value, and the reactive current value.

[0014] In one embodiment, the apparatus is A limit value module configured to acquire the terminal voltage history of a dual-feed wind turbine in the event of a failure in an integrated wind and thermal power generation system, and to determine the limit value of the low-voltage active limit logic based on the terminal voltage history, An active current value module configured to acquire an active current value based on a preset maximum capacity of a current transformer and a limit value of a low-voltage active limit logic, The system further comprises a second limit value module configured to determine a second limit value based on the maximum capacity of the current transformer, the limit value of the low-voltage active limit logic, and the active current value.

[0015] This application is, The system includes memory, a processor, and a computer program stored in memory and executable by the processor, and when the processor executes the program, the above method is realized. We will provide even more electronic devices.

[0016] This application is, A computer program that causes the computer to perform the above method is stored in the computer. Further computer-readable storage media will be provided.

[0017] This application is, When executed by a processor, it includes a computer program / instruction that accomplishes the steps of the above method, We will provide even more computer program products. [Brief explanation of the drawing]

[0018] [Figure 1] This is a flowchart of the transient stability control method for an integrated wind and thermal power generation system according to an embodiment of the present invention. [Figure 2] This is a flowchart for determining the first limit value in the embodiment of the present application. [Figure 3] This is a flowchart for determining the second limit value in the embodiment of the present application. [Figure 4] This is a schematic diagram illustrating the control of transient current commands for the rotor converter in an embodiment of the present invention. [Figure 5A] This is a schematic diagram illustrating the relationship between the active / reactive current and terminal voltage of a dual-powered wind turbine during a failure period in an embodiment of the present invention. [Figure 5B] This is a schematic diagram illustrating the relationship between the active / reactive current and terminal voltage of a dual-powered wind turbine during a failure period in an embodiment of the present invention. [Figure 6] This is a topology map of the integrated wind and thermal power generation system in an embodiment of the present invention. [Figure 7] This is a schematic diagram of the terminal voltage of a dual-feed wind turbine with 50% wind turbine connection at fault location 2 in an embodiment of the present invention, and with different reactive current injection coefficients. [Figure 8A] This is a schematic diagram of the power angle change of the synchronous machine group at different reactive current injection coefficients for fault location 1 in an embodiment of the present invention. [Figure 8B] This is a schematic diagram of the power angle change of the synchronous machine group at different reactive current injection coefficients for fault location 1 in an embodiment of the present invention. [Figure 8C] This is a schematic diagram of the power angle change of the synchronous machine group at different reactive current injection coefficients for fault location 1 in an embodiment of the present invention. [Figure 9A] This is a schematic diagram of the power angle change of the synchronous machine group at different reactive current injection coefficients at fault location 2 in the embodiment of the present invention. [Figure 9B] This is a schematic diagram of the power angle change of the synchronous machine group at different reactive current injection coefficients at fault location 2 in the embodiment of the present invention. [Figure 9C] This is a schematic diagram of the power angle change of the synchronous machine group at different reactive current injection coefficients at fault location 2 in the embodiment of the present invention. [Figure 10A] This is a schematic diagram showing the terminal voltage, active current, and power angle changes of a dual-feed wind turbine with different reactive current injection coefficients during a metal-to-ground fault at fault location 1 in an embodiment of the present invention. [Figure 10B] This is a schematic diagram showing the terminal voltage, active current, and power angle changes of a dual-feed wind turbine with different reactive current injection coefficients during a metal-to-ground fault at fault location 1 in an embodiment of the present invention. [Figure 10C]This is a schematic diagram showing the terminal voltage, active current, and power angle changes of a dual-feed wind turbine with different reactive current injection coefficients during a metal-to-ground fault at fault location 1 in an embodiment of the present invention. [Figure 11A] This is a schematic diagram showing the terminal voltage, active current, and power angle changes of the synchronous machine group of a dual-feed wind turbine with different reactive current injection coefficients during a metal-to-ground fault at fault location 2 in an embodiment of the present invention. [Figure 11B] This is a schematic diagram showing the terminal voltage, active current, and power angle changes of the synchronous machine group of a dual-feed wind turbine with different reactive current injection coefficients during a metal-to-ground fault at fault location 2 in an embodiment of the present invention. [Figure 11C] This is a schematic diagram showing the terminal voltage, active current, and power angle changes of the synchronous machine group of a dual-feed wind turbine with different reactive current injection coefficients during a metal-to-ground fault at fault location 2 in an embodiment of the present invention. [Figure 12A] This is a schematic diagram showing the terminal voltage, active current, and power angle changes of a dual-feed wind turbine with different reactive current injection coefficients during a non-metallic ground fault at fault location 1 in an embodiment of the present invention. [Figure 12B] This is a schematic diagram showing the terminal voltage, active current, and power angle changes of a dual-feed wind turbine with different reactive current injection coefficients during a non-metallic ground fault at fault location 1 in an embodiment of the present invention. [Figure 12C] This is a schematic diagram showing the terminal voltage, active current, and power angle changes of a dual-feed wind turbine with different reactive current injection coefficients during a non-metallic ground fault at fault location 1 in an embodiment of the present invention. [Figure 13] This is a schematic diagram of the structure of a transient stability control device for an integrated wind and thermal power generation system according to an embodiment of the present invention. [Figure 14] This is a schematic diagram of the structure of a transient stability control device for an integrated wind and thermal power generation system in another embodiment of the present invention. [Figure 15] This is a schematic diagram of the structure of a control device for transient stability of an integrated wind and thermal power generation system in a further embodiment of the present invention. [Figure 16] This is a schematic diagram of the structure of an electronic device according to one embodiment of the present invention. [Modes for carrying out the invention]

[0019] Embodiments of the present invention provide a method and apparatus for controlling the transient stability of an integrated wind power and thermal power generation system.

[0020] The embodiments of this application will be described clearly and completely below, in conjunction with the drawings of the embodiments. The embodiments described are only some of the embodiments of this application, not all of them.

[0021] As shown in Figure 1, control of transient stability of the wind power and thermal power integrated system of the embodiment of the present invention This is a flowchart of the method, and the implementing body of the transient stability control method for an integrated wind and thermal power generation system according to the embodiment of the present application includes a computer. The present application provides rapid and effective transient stability control of a dual-fed wind turbine by determining the trend of the effect of the reactive current injection coefficient on the transient stability of an integrated wind and thermal power generation system, thereby improving the transient stability control effect of the integrated wind and thermal power generation system, increasing control efficiency and practicality, and providing a basis for adjusting the transient control parameters of the dual-fed wind turbine. The method shown in the figure includes the following steps.

[0022] In step S1, the terminal voltage of the dual-powered wind turbine is acquired in real time in the event of a failure in the integrated wind and thermal power generation system.

[0023] In step S2, upon receiving that the terminal voltage of the dual-feed wind turbine is in the first voltage drop section, the amplitude of the acceleration phase of the synchronous generator during the fault period is reduced by increasing the reactive current injection coefficient of the dual-feed wind turbine according to a predetermined adjustment rule.

[0024] In step S3, given that the terminal voltage of the dual-feed wind turbine is in the second voltage drop section, the amplitude of the acceleration phase and the deceleration phase of the synchronous generator during the failure period are reduced by increasing the reactive current injection coefficient of the dual-feed wind turbine according to the adjustment rule.

[0025] In step S4, given that the terminal voltage of the dual-feed wind turbine is in the third voltage drop section, the amplitude of the deceleration phase of the synchronous generator during the failure period is reduced by decreasing the reactive current injection coefficient of the dual-feed wind turbine according to the adjustment rule.

[0026] Here, the reactive injection coefficient is a proportional parameter that determines how much reactive current a dual-fed wind turbine preferentially injects into the power grid based on the degree of voltage drop in the power grid. During a failure in an integrated wind and thermal power system, the active and reactive currents of the dual-fed wind turbines in the integrated wind and thermal power system change in accordance with the changes in the terminal voltage of the dual-fed wind turbines. Specifically, the degree of terminal voltage drop can be divided into three cases depending on the phase that leads the transient control of the active and reactive currents.

[0027] In some embodiments, when the terminal voltage of a dual-feed wind turbine is in the second voltage drop zone, the reactive current increases with decreasing terminal voltage, driven by the reactive proportional injection phase, while the active current decreases with decreasing terminal voltage, driven by the limiting phase of the Low Voltage Active Power Limiting Logic (LVPL), leaving a margin for the converter.

[0028] In some embodiments, when the terminal voltage of a dual-fed wind turbine is in the third voltage drop section, the reactive current is still driven by the reactive proportional injection phase, but the active current is limited by the reactive current and maximum capacity and decreases with decreasing terminal voltage. When the terminal voltage of a dual-fed wind turbine is in the first voltage drop section, the reactive current reaches the converter's maximum capacity and stops changing with decreasing terminal voltage, and the active current is 0.

[0029] Here, by making different adjustments to the reactive current injection coefficient of the dual-fed wind turbine in different voltage drop sections, precise control of transient stability in the event of a failure in the integrated wind and thermal power generation system is achieved. In some embodiments, the preset adjustment rules can be set according to the actual operating conditions, for example, by setting the increment value, decrement value, and number of adjustments for each adjustment of the reactive current injection coefficient of the dual-fed wind turbine.

[0030] In some embodiments, the first synchronous generator in a wind power and thermal power integrated system When focusing on the amplitude of the oscillation (acceleration phase of the synchronous generator during the fault period), analysis of relevant historical data revealed that as the reactive current injection coefficient of the dual-fed wind turbine increased, the amplitude of the first oscillation of the synchronous generator decreased, improving the transient stability of the integrated wind and thermal power system. Furthermore, when focusing on the amplitude of the second oscillation of the synchronous generator in the integrated wind and thermal power system (deceleration phase of the synchronous generator after the fault has been removed), it is necessary to consider the starting value of the increase in active current during the fault recovery period. Thus, the starting value of the increase in active current varies depending on the different voltage drop intervals, i.e., the first, second, and third voltage drop intervals, in accordance with the change in the reactive current injection coefficient of the dual-fed wind turbine.

[0031] For example, within the first voltage drop section, the active current in the initial stages of fault recovery starts to rise from 0. At this time, the starting value of the rise in active current does not change with the reactive current injection coefficient of the dual-fed wind turbine, remaining at 0 in all cases. This indicates that the effect of the reactive current injection coefficient of the dual-fed wind turbine on the transient stability of the integrated wind and thermal power system is small. Within the second voltage drop section, as the reactive current injection coefficient of the dual-fed wind turbine increases, the amplitude of the second deflection decreases, which is favorable for the transient stability of the integrated wind and thermal power system. Within the third voltage drop section, the amplitude of the second deflection decreases with increasing reactive current injection coefficient of the dual-fed wind turbine. However, when the reactive current injection coefficient of the dual-fed wind turbine increases to a certain value (generally 5) or higher, the second deflection conversely increases with the reactive current injection coefficient of the dual-fed wind turbine, which is unfavorable for the transient stability of the integrated wind and thermal power system.

[0032] This revealed that when controlling the transient stability of an integrated wind and thermal power generation system using the reactive current injection coefficient of a dual-fed wind turbine, it is necessary to focus primarily on the amplitude of the second oscillation. This is because the amplitude of the first oscillation decreases as the reactive current injection coefficient of the dual-fed wind turbine increases. Therefore, when controlling the system to reduce the reactive current injection coefficient of the dual-fed wind turbine, it is necessary to reduce the second oscillation as slowly as possible, that is, to ensure that the amplitude of the first oscillation does not increase significantly while reducing the amplitude of the second oscillation.

[0033] In some embodiments, the reactive current injection coefficient of the dual-fed wind turbine increases within the first and second voltage drop intervals, which is advantageous in ensuring the transient stability of the integrated wind and thermal power generation system. Furthermore, as the reactive current injection coefficient of the dual-fed wind turbine increases, the first amplitude also decreases simultaneously. Therefore, when setting the adjustment rules, the increment value of the reactive current injection coefficient of the dual-fed wind turbine can be set to 0.5 or 1 each time, and this setting method can significantly improve the control efficiency of the transient stability of the integrated wind and thermal power generation system. In addition, the increment value of the reactive current injection coefficient of the dual-fed wind turbine can be set according to the actual situation.

[0034] In some embodiments, the amplitude of the first oscillation can be increased by reducing the reactive current injection coefficient of the dual-fed wind turbine. Therefore, within the third voltage drop section, the decrease value corresponding to the reactive current injection coefficient of the dual-fed wind turbine in the adjustment rule is smaller than the increase value. For example, the decrease value each time is 0.2, which enables an appropriate reduction of the reactive current injection coefficient of the dual-fed wind turbine, ensuring that the amplitude of the first oscillation does not become excessive, while also reducing the amplitude of the second oscillation and improving the transient stability of the integrated wind and thermal power system.

[0035] In some embodiments, the first voltage drop interval is less than the first limit value, the second voltage drop interval is greater than the second limit value and less than a preset upper voltage value, and the third voltage drop interval is greater than the first limit value and less than the second limit value.

[0036] Here, when setting the first, second, and third voltage drop sections, the upper and lower limits of each section are determined. It is necessary. For example, the first limit value U t1 This is the boundary value between the first voltage drop section and the third voltage drop section, and the second limit value U t2 This is the boundary value between the third voltage drop section and the second voltage drop section, and the preset voltage upper limit U1 is the upper limit of the second voltage drop section. The voltage upper limit can be adjusted and set according to the actual operating conditions.

[0037] In this embodiment, as shown in Figure 2, the method further includes the following steps.

[0038] In step S21, the terminal voltage history and reactive current injection coefficient history of the dual-feed wind turbine during a failure of the integrated wind and thermal power generation system are obtained, and the reactive current value is determined based on the terminal voltage history and reactive current injection coefficient history.

[0039] In step S22, the reactive current value is obtained based on the preset maximum capacity of the current transformer and the reactive injection current value.

[0040] In step S23, the first limit value is determined based on the maximum capacity of the current transformer, the reactive injection current value, and the reactive current value.

[0041] In some embodiments, the boundary values of each voltage drop interval can be determined based on the historical data during a fault of the wind power and thermal power integrated system. Exemplarily, as shown in the control schematic diagram of the transient current command of the rotor converter shown in FIG. 4, the reactive injection current can be obtained from the terminal voltage of the dual-fed wind generator and the reactive current injection coefficient, and it is found that the reactive injection current value can be determined by using the terminal voltage history and the reactive current injection coefficient history. Further, the reactive current value can be obtained from the reactive injection current value and the preset maximum capacity of the converter, and the process of obtaining the reactive injection current value and the reactive current value can adopt the conventional method.

[0042] In some embodiments, the reactive injection current value i determined based on different terminal voltage histories and reactive current injection coefficient histories p rq_inj +i p rq_ctrl_10 and the reactive current value i p rq are associated with the maximum capacity I of the converter as shown in FIG. 5A, and the intersection of these three lines is the first limit value U rmax which is. t1

[0043] In this embodiment, as shown in FIG. 3, the method further includes the following steps.

[0044] In step S31, the terminal voltage history of the dual-fed wind generator during a fault of the wind power and thermal power integrated system is obtained, and the limit value of the low-voltage active limit logic is determined based on the terminal voltage history.

[0045] In step S32, the active current value is obtained based on the preset maximum capacity of the converter and the limit value of the low-voltage active limit logic.

[0046] In step S33, the second limit value is determined based on the maximum capacity of the converter, the limit value of the low-voltage active limit logic, and the active current value.

[0047] ​As shown in Figure 4, similar to the method for determining the first limit value, the LVPL limit, which is the limit value of the low-voltage effective limiting logic, can be determined by utilizing the terminal voltage history of the dual-fed wind turbine during a failure in the integrated wind and thermal power generation system. The effective current value can be determined by utilizing the limit value of the low-voltage effective limiting logic and the preset maximum capacity of the current transformer. Conventional methods can be used for the process of determining the effective current value and the limit value of the low-voltage effective limiting logic.

[0048] In some examples, the low-voltage effective limit theory was determined based on different terminal voltage histories. The limit value of reason i p rdmax2 and the effective current value i p rd As shown in Figure 5B, the maximum capacity of the current transformer I rmax In connection with this, the intersection of these three lines is the second limit value U t2 That is the case.

[0049] This invention aims to provide rapid and effective control of the transient stability of a dual-fed wind turbine by determining the trend of the effect of the reactive current injection coefficient on the transient stability of an integrated wind and thermal power generation system. This will improve the transient stability control effect of the integrated wind and thermal power generation system, enhance control efficiency and practicality, and provide a basis for adjusting the transient control parameters of the dual-fed wind turbine.

[0050] In some embodiments, the transient control policy for the rotor-side transducer of a dual-powered wind turbine is as shown in Figure 4: during the transient control operation period, all normal control integrators are frozen and retain the steady-state values ​​before the failure. p rq_ctrl This is the reactive current output under normal control, i p rd_ctrl This is the active current output under normal control.

[0051] Here, in the invalid branch circuit, the steady-state value i before the failure p rq_ctrl and the injected current i obtained in the inactive injection phasep rq_inj is the converter capacity limit i rmax After being restricted by, the actual reactive current command i p rq is obtained, and U t is the voltage amplitude value at the terminal voltage, and U tref is the terminal voltage reference value, and k qv is the reactive injection coefficient.

[0052] In some embodiments, in the active branch part, the pre-fault steady value i p rd_ctrl is the converter capacity limit i p rdmax1 and the LVPL limit i p rdmax2 After being restricted by both, the actual active current command i p rd is obtained. Here, in the LVPL limit phase, based on the drop situation of the terminal voltage U t the limit value i p rdmax2 of the active current of the dual-fed wind generator is calculated, and when U t > U1, there is no limit value for the active current, and when U0 < U t < U1, the limit value of the active current and the voltage are linearly related. The lower the voltage, the smaller the limit value of the active current. When U t < U0, the limit value of the active current is 0.

[0053] In transient control, the reactive current i p rq of the dual-fed wind generator is p rq_ctrl the sum of the pre-fault steady value i p rq_inj and the reactive current injection i rmax p and the minimum value of the converter capacity limit i rq is determined by, and i p rq_ctrl = min{i p rq_inj + i rmax}, where the pre-fault steady value i p rq_ctrland the capacity limit i of the converter rmax is independent of the degree of failure and is only the reactive current injection i p rq_inj that is related to the terminal voltage amplitude value U t during the fault period and the reactive current injection coefficient k qv In a system with the same structure and operating conditions, the reactive current i p rq during the fault period is dependent on the terminal voltage U t and the reactive current injection coefficient k qv That is, i p <000007l>= F irq (U t , k qv ). The active current i p rd is composed of both the LVPL limit i p rdmax2 andthe constraint of the converter capacity limit i p rdmax1 , i p rd = min{i p rdmax1 , i p rdmax2}. Here, the LVPL limit i p rdmax2 is related to the terminal voltage amplitude value U t and the slope k d of the LVPL limit curve. The constraint of the converter capacity limit i p rdmax1 is related to the reactive current i p rq . The reactive current i p rq is dependent on the terminal voltage amplitude value U t . Therefore, the active current i p rd is dependent on the terminal voltage amplitude value U t , the slope k d of the LVPL limit curve, and the reactive current injection coefficient k qv , that is, i p rd = F ird (U t , k d , k qv ).

[0054] Here, FIGS. 5A and 5B respectively show the tendency of change in the terminal voltage U irq (U t ,k qv ) and U ird (U t ,k d ,k qv ). The degree of terminal voltage drop can be divided into three cases according to the phase that dominates the transient control of the active current and the reactive current. Second voltage drop interval: When U t2 < U t < U1, the reactive current is dominated by the reactive proportional injection phase and increases as the terminal voltage decreases, and the active current is dominated by the LVPL limit t phase and decreases as the terminal voltage decreases, and there is still margin in the converter. Third voltage drop interval: When U t1 < U t < U t2 , the reactive current is still dominated by the reactive proportional injection phase, but the active current is limited by the reactive current and the maximum capacity and decreases as the terminal voltage decreases. First voltage drop interval: When U t < U t1 , the reactive current reaches the maximum capacity of the converter and does not change as the terminal voltage decreases, and the active current is 0.

[0055]

[0056] In this embodiment, relevant historical data is used to determine the tendency rule of the influence on the transient stability of the system by different wind power connection ratios and the reactive current injection coefficients in different faults.

[0056] Here, the reactive current injection coefficient dominates the transient characteristics during the fault period of the dual-fed wind generator, takes the wind power thermal power integrated power transmission system as the research object, reflects the transient stability of the system by the power angle of the synchronous generator group, studies the tendency of the influence on the transient stability of the system by the reactive current injection coefficient, and gives an interpretation of the mechanism.

[0057] In some embodiments, the topology of the integrated wind and thermal power generation system is as shown in Figure 6, where the dual-fed wind turbines and synchronous generators are connected to an infinite power grid via three double-circuit transmission lines, the synchronous generators have a capacity of 4000 MW, and the dual-fed wind turbines are connected according to different wind power connection ratios of 50%, 30%, and 10%, with corresponding capacities of 4000 MW, 1714.29 MW, and 444.44 MW, respectively. The fault is a three-phase ground fault with a fault duration of 0.1 s, and the fault location includes (1) Fault_1 in the busbar and (2) Fault_2, Fault_3, and Fault_4 in the middle of one of the double-circuit transmission lines. In the figure, DFIG is a dual-fed wind turbine and SG is a synchronous generator.

[0058] The reactive current injection coefficient k is calculated for wind turbine connection proportionality of 50%, 30%, and 10% and different fault locations. qv The power angle waveform of the synchronous generator is changed, and the power angle of the synchronous generator (with the voltage phase of infinite power supply 1 as the reference phase) is obtained. The power angle of the synchronous generator is then used as the evaluation criterion for the transient stability of the system.

[0059] Here, when we focus on the amplitude of the first deflection (the acceleration phase of the synchronous generator during the failure period), the reactive current injection coefficient k of the dual-feed wind turbine is... qv As k increased, the amplitude of the first oscillation of the synchronous generator decreased, and the transient stability of the system improved, as shown in Figures 8A-8C and 9A-9C, where Figures 8A and 9A are 50% wind power connection proportional, Figures 8B and 9B are 30% wind power connection proportional, and Figures 8C and 9C are 10% wind power connection proportional. This is because k qv As a result of this increase, the dual-feed wind turbine can output more reactive power during a failure period, its voltage support capacity becomes stronger, the voltage drop at the point of failure decreases (as shown in Figure 7, for example), the output of active power from the synchronous machine increases, the unbalanced power (the difference between input mechanical power and output electromagnetic power) experienced by the synchronous machine decreases, and transient stability improves.

[0060] In some embodiments, when paying attention to the amplitude of the second swing (the deceleration stage of the synchronous generator after the fault is removed), it is necessary to consider the starting value of the increase in the effective current during the fault recovery period, which can be divided into the following three cases.

[0061] 1) During the fault period U t <U t1 In the case of, as shown in Fig. 10A, the limit value of the effective current obtained by LVPL is 0 (a three-phase metallic ground fault occurred in the busbar). The effective current at the initial stage of fault recovery starts to increase from 0. As shown in Fig. 10B, in this case, the starting value of the increase in the effective current does not change with qv and is 0 in all cases. The influence of qv on the transient stability of the system is small. The power angle of the synchronous machine is as shown in Fig. 10C.

[0062] 2) During the fault period U t2 <U t <U1, as shown in Fig. 11A, is a schematic diagram of the terminal voltage of the dual-fed wind power generator with different reactive current injection coefficients during the metallic ground fault at fault location 2. As shown in Fig. 11B, it is a schematic diagram of the effective current with different reactive current injection coefficients during the metallic ground fault at fault location 2. The limit value of the effective current is linearly related to the voltage but is not limited by the capacity of the converter (a three-phase metallic ground fault occurred in the middle of one of the two-line lines). In this case, the larger qv is, the stronger the voltage support ability is, the higher the terminal voltage of the dual-fed wind power generator is, and the larger the limit value of the effective current obtained by LVPL is, the larger the starting value of the increase in the effective current at the initial stage of fault recovery is, and it is easier to recover. As shown in Fig. 11C, it is a schematic diagram of the power angle change of the synchronous machine group with different reactive current injection coefficients during the metallic ground fault at fault location 2. With the increase of qv , the amplitude of the second swing decreases, which is beneficial to the transient stability of the system.

[0063] 3) During the fault period U t1 <U t <U t2In this case, as shown in Figure 12A, it is a schematic diagram of the terminal voltage at different reactive current injection coefficients during a nonmetallic ground fault at fault location 1, limited by the current transformer capacity (a three-phase nonmetallic ground fault occurred at the busbar).

[0064] Here, k qv As it increases to a certain extent, it is limited by the current transformer capacity, the limit value of the active current decreases and then becomes 0, and the starting value for the increase of the active current decreases and then becomes 0. As shown in Figure 12B, this is a schematic diagram of the active current at different reactive current injection coefficients during a non-metallic ground fault at fault location 1. As the starting value for the increase decreases and then becomes 0, even if the increase coefficient is the same, the starting point is lower, so recovery after the fault is slower, the amplitude of the second deflection is larger, and it is unfavorable for the transient stability of the system. As shown in Figure 12C, this is the power angle change of the synchronous machine group at different reactive current injection coefficients during a non-metallic ground fault at fault location 1, k qv If is small, the amplitude of the second deflection is k qv It decreases as k increases, qv When increases to 5 or more, the amplitude of the second deflection is reversed to k qv It was found that this increases with the increase in [something], which is detrimental to the transient stability of the system.

[0065] In this embodiment, using the power system shown in Figure 6 as an example, we will explain a method for improving the transient stability of a system by adjusting the reactive injection coefficient of a dual-feed wind turbine.

[0066] In the event of a serious power grid failure, the terminal voltage of dual-fed wind turbines is monitored in real time during the failure period, and the magnitude of the reactive injection coefficient is determined based on the degree of voltage drop of the dual-fed wind turbines.

[0067] 1) U during the failure period t t1 In this case, that is, when the terminal voltage of the dual-feed wind turbine is in the first voltage drop section, the reactive current injection coefficient k of the dual-feed wind turbine is qv ​By increasing it, the amplitude of the first swing of the synchronous generator is reduced, but the amplitude of the second swing is hardly affected, improving the transient stability of the system.

[0068] 2) During the fault, U t2 <U t When <U1, that is, when the terminal voltage of the dual-fed wind generator is in the second voltage drop interval, the reactive current injection coefficient k of the dual-fed wind generator qv By increasing it, the amplitudes of the first swing and the second swing of the synchronous generator can be simultaneously reduced, improving the transient stability of the system.

[0069] 3) During the fault, U t1 <U t <U t2 When <U, that is, when the terminal voltage of the dual-fed wind generator is in the third voltage drop interval, the reactive current injection coefficient k of the dual-fed wind generator qv By appropriately reducing it, the amplitude of the second swing of the synchronous generator is reduced, and the amplitude of the first swing is not excessively increased, improving the transient stability of the system.

[0070] Here, the adjustment of the reactive current injection coefficient of the dual-fed wind generator can be performed according to a preset rule.

[0071] Simultaneously consider the influence on the transient stability of the system by the acceleration stage (amplitude of the first swing) of the synchronous generator during the fault and the deceleration stage (amplitude of the second swing) of the generator after the fault is removed.

[0072] This application found through theory and simulation analysis that at the initial stage of fault recovery, when the effective rise coefficient is the same, the amplitude of the second swing is affected by the starting value of the rise of the active current. Based on the amplitude value of the terminal voltage during the fault, the starting value of the rise of the active current is divided into three cases as shown in the following formula.

Equation

[0073] In particular, during the fault, Ut1 t t2 In this case, the active current is limited by the capacity of the current transformer, k qv As k increases, the starting point for the rise in active current decreases, which may increase the second amplitude and is detrimental to the transient stability of the system. This is because when focusing only on the amplitude of the first deflection, "k qv This is contrary to the conclusion that "an increase is advantageous," so it is necessary to comprehensively consider the effects of two stages: acceleration of the synchronous generator during the failure period and deceleration of the generator after the failure has been removed.

[0074] Furthermore, theoretical and simulation analyses of this method reveal that, when not limited by the capacity of the wind turbines, increasing the reactive current injection coefficient is advantageous for the transient stability of the system, and when limited by the capacity of the wind turbines, appropriately reducing the reactive current injection coefficient is advantageous for the transient stability of the system. Moreover, this effect becomes greater as the proportion of wind power generation increases.

[0075] This invention aims to provide rapid and effective control of the transient stability of a dual-fed wind turbine by determining the trend of the effect of the reactive current injection coefficient on the transient stability of an integrated wind and thermal power generation system. This will improve the transient stability control effect of the integrated wind and thermal power generation system, enhance control efficiency and practicality, and provide a basis for adjusting the transient control parameters of the dual-fed wind turbine.

[0076] As shown in Figure 13, this is a schematic diagram of the structure of a transient stability control device for an integrated wind and thermal power generation system according to an embodiment of the present invention, and the device shown in the figure is A terminal voltage module 10 is configured to acquire the terminal voltage of a dual-feed wind turbine in real time in the event of a failure in an integrated wind power and thermal power generation system, The first voltage drop section module 20 is configured to reduce the amplitude of the acceleration phase of the synchronous generator during the failure period by increasing the reactive current injection coefficient of the dual-powered wind turbine in accordance with a preset adjustment rule, in response to the terminal voltage of the dual-powered wind turbine being in the first voltage drop section, ​​In response to the terminal voltage of the dual-feed wind turbine being in the second voltage drop section, a second voltage drop section module 30 is configured to reduce the amplitude of the acceleration phase and the deceleration phase of the synchronous generator during the failure period by increasing the reactive current injection coefficient of the dual-feed wind turbine according to the adjustment rules, Given that the terminal voltage of the dual-feed wind turbine is in the third voltage drop zone, the reactive current injection coefficient of the dual-feed wind turbine is reduced in accordance with the adjustment rule, thereby synchronizing during the fault period. The system includes a third descent section module 40 configured to reduce the amplitude of the deceleration phase of the generator.

[0077] In some embodiments, the first voltage drop interval is less than the first limit value, the second voltage drop interval is greater than the second limit value and less than a preset upper voltage value, and the third voltage drop interval is greater than the first limit value and less than the second limit value.

[0078] In this embodiment, as shown in Figure 14, the apparatus is A reactive injection module 21 is configured to acquire the terminal voltage history and reactive current injection coefficient history of a dual-feed wind turbine in the event of a failure in an integrated wind power generation and thermal power generation system, and to determine the reactive current injection value based on the terminal voltage history and reactive current injection coefficient history. A reactive current value module 22 is configured to acquire a reactive current value based on a preset maximum capacity of a current transformer and a reactive injection current value, The system further comprises a first limit value module 23 configured to determine a first limit value based on the maximum capacity of the current transformer, the reactive injection current value, and the reactive current value.

[0079] In this embodiment, as shown in Figure 15, the apparatus is A limit value module 31 is configured to acquire the terminal voltage history of a dual-feed wind turbine in the event of a failure in an integrated wind power generation and thermal power generation system, and to determine the limit value of the low-voltage active limit logic based on the terminal voltage history, An active current value module 32 is configured to acquire an active current value based on a preset maximum capacity of the current transformer and a limit value of the low-voltage active limit logic, The system further comprises a second limit value module 33 configured to determine a second limit value based on the maximum capacity of the current transformer, the limit value of the low-voltage active limit logic, and the active current value.

[0080] Based on the same patent concept as the method for controlling the transient stability of the wind-power and thermal power integrated system described above, this application further provides a control device for the transient stability of the wind-power and thermal power integrated system. Since the principle of solving the problem of the control device for the transient stability of the wind-power and thermal power integrated system is similar to the method for controlling the transient stability of the wind-power and thermal power integrated system, the implementation of the control device for the transient stability of the wind-power and thermal power integrated system can be based on the implementation of the method for controlling the transient stability of the wind-power and thermal power integrated system, and a repeated explanation will be omitted.

[0081] This invention aims to provide rapid and effective control of the transient stability of a dual-fed wind turbine by determining the trend of the effect of the reactive current injection coefficient on the transient stability of an integrated wind and thermal power generation system. This will improve the transient stability control effect of the integrated wind and thermal power generation system, enhance control efficiency and practicality, and provide a basis for adjusting the transient control parameters of the dual-fed wind turbine.

[0082] The present invention further provides an electronic device that includes memory, a processor, and a computer program stored in the memory and executable by the processor, wherein the processor executes the program, thereby realizing the above method.

[0083] The present invention further provides a computer program product that includes a computer program / instruction that, when executed by a processor, realizes the steps of the above method.

[0084] The present invention further provides a computer-readable storage medium in which a computer program that causes a computer to perform the above method is stored.

[0085] As shown in Figure 16, the electronic device 600 further includes components such as a communication module 110, an input unit 120, an audio processor 130, a display 160, and a power supply 170. However, the electronic device 600 may include some of the components shown in Figure 16, or it may include components not shown in Figure 16.

[0086] As shown in Figure 16, the central processor 100 may also be called a controller or processor, and may include a microprocessor, other processor devices and / or logic devices, and the central processor 100 receives inputs and controls the operation of each component of the electronic device 600.

[0087] Here, memory 140 may be a buffer, flash memory, hard drive, removable media, volatile memory, non-volatile memory, or one or more other suitable devices. It can store information related to the above-mentioned failure, and can also store a program to execute the related information. The central processor 100 can execute the program stored in memory 140 to store or process the information.

[0088] The input unit 120 provides input to the central processor 100. The input unit 120 may be a key or touch input device. The power supply 170 is used to supply power to the electronic device 600. The display 160 is used to display images, characters, and other display objects. The display may be a liquid crystal display (LCD).

[0089] The memory 140 may be a solid-state memory such as read-only memory (ROM), random access memory (RAM), or USB. It may also be a memory that retains information even when the power is turned off, can be selectively erased, and can store more data, for example, an erasable programmable read-only memory. It may be Read-Only Memory (EPROM), etc. Memory 140 may be of other types. Memory 140 includes a buffer memory 141 (sometimes called a buffer). Memory 140 may also include an application / function storage unit 142 for storing application programs and function programs, and for the central processor 100 to execute the operation flow of the electronic device 600.

[0090] The memory 140 may further include a data storage unit 143 for storing data such as contacts, digital data, photographs, audio and / or any other data used by the electronic device. The driver program storage unit 144 of the memory 140 may include various driver programs for the communication functions of the electronic device and / or for performing other functions of the electronic device (e.g., message transmission applications, address book applications, etc.).

[0091] The communication module 110 is a transmitter / receiver 110 that transmits and receives signals via the antenna 111. The communication module (transmitter / receiver) 110 is connected to the central processor 100 to provide input signals and receive output signals, which is the same as in conventional mobile communication terminals.

[0092] Based on different communication technologies, the same electronic device may be equipped with multiple communication modules 110, such as a cellular network module, a Bluetooth module, and / or a wireless local area network module. The communication module (transmitter / receiver) 110 is further coupled to a speaker 131 and a microphone 132 via an audio processor 130, providing audio output via the speaker 131 and receiving audio input from the microphone 132, thereby realizing conventional telecommunication functions. The audio processor 130 may include any suitable buffer, decoder, amplifier, etc. The audio processor 130 is further connected to the central processor 100, and can record audio via the microphone 132 and play back the audio stored in the device via the speaker 131.

[0093] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Accordingly, this application may take the form of complete hardware embodiments, complete software embodiments, or embodiments combining software and hardware. Furthermore, this application may take the form of a computer program product implemented on one or more computer-readable storage media (including magnetic disk memory, Compact Disc Read-Only Memory (CD-ROM), optical memory, etc.) containing computer-readable program code.

[0094] This application will be described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of this application. It should be understood that computer program instructions can realize each flow and / or block in the flowcharts and / or block diagrams, and combinations of flows and / or blocks in the flowcharts and / or block diagrams. To generate a device, these computer program instructions can be provided to the processor of a general-purpose computer, a dedicated computer, an embedded processor, or other programmable data processing device, so that the instructions executed by the processor of the computer or other programmable data processing device generate a device to realize a function specified in one flow of a flowchart or one or more blocks of multiple flows and / or block diagrams.

[0095] These computer program instructions may be stored in computer-readable memory that can guide a computer or other programmable data processing device to operate in a particular manner, thereby generating a product that includes an instruction unit that implements a function specified in one or more flows of a flowchart and / or one or more blocks of a block diagram.

[0096] These computer program instructions may be loaded into a computer or other programmable data processing device to generate processing that the computer or programmable device performs by executing a series of operational steps, and the instructions executed by the computer or programmable device provide steps to realize a function specified in one or more flows of a flowchart and / or one or more blocks of a block diagram.

Claims

1. To acquire the terminal voltage of a dual-feed wind turbine in real time during a failure of an integrated wind power generation and thermal power generation system, In response to the terminal voltage of the dual-feed wind turbine being in the first voltage drop zone, the amplitude of the acceleration phase of the synchronous generator during the failure period is reduced by increasing the reactive current injection coefficient of the dual-feed wind turbine according to a predetermined adjustment rule. In response to the terminal voltage of the dual-feed wind turbine being in the second voltage drop zone, the reactive current injection coefficient of the dual-feed wind turbine is increased in accordance with the adjustment rule, thereby reducing the amplitude of the acceleration phase and the deceleration phase of the synchronous generator during the failure period. Receiving that the terminal voltage of the dual-feed wind turbine is in the third voltage drop section, the amplitude of the deceleration phase of the synchronous generator during the failure period is reduced by reducing the reactive current injection coefficient of the dual-feed wind turbine in accordance with the adjustment rule, including: A method for controlling the transient stability of an integrated wind and thermal power generation system.

2. The first voltage drop interval is less than the first limit value, the second voltage drop interval is greater than the second limit value and less than the preset upper voltage value, and the third voltage drop interval is greater than the first limit value and less than the second limit value. A method for controlling the transient stability of an integrated wind power and thermal power generation system according to claim 1.

3. The terminal voltage history and reactive current injection coefficient history of a dual-feed wind turbine during a failure in an integrated wind power generation and thermal power generation system are acquired, and the reactive current injection value is determined based on the terminal voltage history and the reactive current injection coefficient history. The reactive current value is obtained based on the preset maximum capacity of the current transformer and the reactive injection current value, The further step is to determine a first limit value based on the maximum capacity of the current transformer, the reactive injection current value, and the reactive current value. A method for controlling the transient stability of an integrated wind power and thermal power generation system according to claim 2.

4. The system acquires the terminal voltage history of a dual-feed wind turbine in the event of a failure in an integrated wind and thermal power generation system, and determines the limit value of the low-voltage active limiting logic based on the terminal voltage history. The active current value is obtained based on the preset maximum capacity of the current transformer and the limit value of the low-voltage active limiting logic, The further step includes determining a second limit value based on the maximum capacity of the current transformer, the limit value of the low-voltage active limiting logic, and the active current value. A method for controlling the transient stability of an integrated wind power and thermal power generation system according to claim 2.

5. A terminal voltage module configured to acquire the terminal voltage of a dual-feed wind turbine in real time during a failure in an integrated wind and thermal power generation system, A first voltage drop section module is configured to reduce the amplitude of the acceleration phase of the synchronous generator during a failure period by increasing the reactive current injection coefficient of the dual-powered wind turbine in accordance with a preset adjustment rule, based on the fact that the terminal voltage of the dual-powered wind turbine is in the first voltage drop section, A second voltage drop section module is configured to reduce the amplitude of the acceleration phase and the deceleration phase of the synchronous generator during a failure period by increasing the reactive current injection coefficient of the dual-powered wind turbine in accordance with the adjustment rule, based on the terminal voltage of the dual-powered wind turbine being in the second voltage drop section, A third voltage drop section module is configured to reduce the amplitude of the deceleration phase of the synchronous generator during a failure period by reducing the reactive current injection coefficient of the dual-powered wind turbine in accordance with the adjustment rule, based on the fact that the terminal voltage of the dual-powered wind turbine is in the third voltage drop section, Equipped with, A control device for transient stability in an integrated wind and thermal power generation system.

6. The first voltage drop interval is less than the first limit value, the second voltage drop interval is greater than the second limit value and less than the preset upper voltage value, and the third voltage drop interval is greater than the first limit value and less than the second limit value. A control device for the transient stability of an integrated wind power and thermal power generation system according to claim 5.

7. A reactive current injection module is configured to acquire the terminal voltage history and reactive current injection coefficient history of a dual-feed wind turbine in the event of a failure in an integrated wind power generation and thermal power generation system, and to determine the reactive current injection value based on the terminal voltage history and the reactive current injection coefficient history. A reactive current value module configured to acquire a reactive current value based on a preset maximum capacity of a current transformer and the reactive injection current value, The system further comprises a first limit value module configured to determine a first limit value based on the maximum capacity of the current transformer, the reactive injection current value, and the reactive current value. A control device for the transient stability of an integrated wind power and thermal power generation system according to claim 6.

8. A limit value module configured to acquire the terminal voltage history of a dual-feed wind turbine in the event of a failure in an integrated wind power and thermal power generation system, and to determine the limit value of the low-voltage active limit logic based on the terminal voltage history, An active current value module configured to acquire an active current value based on a preset maximum capacity of a current transformer and a limit value of the low-voltage active limiting logic, The system further comprises a second limit value module configured to determine a second limit value based on the maximum capacity of the current transformer, the limit value of the low-voltage active limit logic, and the active current value. A control device for the transient stability of an integrated wind power and thermal power generation system according to claim 6.

9. The system includes memory, a processor, and a computer program stored in the memory and executable by the processor, wherein when the processor executes the computer program, the method according to any one of claims 1 to 4 is realized. electronic equipment.

10. A computer program is stored which causes the computer to perform the method described in any one of claims 1 to 4. Computer-readable storage medium.

11. When executed by a processor, the computer program includes a computer program that implements the steps of the method according to any one of claims 1 to 4. Computer program products.

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