A wind farm level small reactive power control method and system
By initializing the wind turbine power management system in the wind farm-level small reactive power control method, calculating the average initial reactive power value, setting control logic flags, arranging the wind turbine status in sequence, and rationally allocating reactive power setpoints, the problem of unstable small reactive power scheduling in the existing technology is solved, higher control accuracy and stability are achieved, and the burden on the wind turbine converter is reduced.
Patent Information
- Application Number
- CN202610231928.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-02-27
- Publication Date
- 2026-06-23
AI Technical Summary
Existing reactive power control methods at the wind farm level suffer from instability issues in low reactive power dispatch scenarios, leading to wind farm outlet voltages failing to meet grid dispatch requirements. This increases the operational burden and losses of SVG equipment. Furthermore, existing technologies cannot effectively address the problems of unreasonable instruction allocation and reactive power jumps in wind turbines under low reactive power dispatch targets.
A wind farm-level reactive power control method is adopted. By initializing the wind turbine power management system, calculating the average initial reactive power value, setting control logic flags, judging the entry conditions of dispatching commands, arranging the wind turbine status in sequence, and rationally allocating reactive power setpoints, the wind farm-level reactive power control process is realized in a loop, avoiding frequent adjustments and power oscillations.
It improves the stability of reactive power control at the wind farm level, reduces the reactive power generation load of the wind turbine converter, meets the grid's dispatch requirements for low reactive power scenarios, and enhances control accuracy and stability.
Smart Images
Figure CN122267934A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of wind farm-level energy control technology, specifically to a wind farm-level low reactive power control method and system. Background Technology
[0002] With the rapid development of the wind power industry, the installed capacity of wind turbines has been increasing year by year, and the proportion of wind farms in the power system has been continuously rising. As a result, the State Grid Corporation of China has been raising its requirements for the stability and security of power grid operation. Among these requirements, reactive power control, as a core component for maintaining grid voltage stability and ensuring power quality, directly affects the safe and efficient operation of the power grid due to its control accuracy and stability.
[0003] Currently, many existing wind farms contain a large number of small-megawatt, outdated wind turbines. These turbines have significant shortcomings in reactive power control capabilities, especially in scenarios with low reactive power control, where instability is particularly prominent. In actual operation, to maintain grid voltage stability, grid dispatching departments often issue small reactive power dispatching instructions, such as 0 kvar, to wind farms to achieve precise regulation of grid voltage.
[0004] Currently, reactive power control at the wind farm level generally adopts the overall PI control method. When dealing with large reactive power dispatch commands at the farm level (i.e., the reactive power of the dispatch command is greater than the sum of the upper or lower limits of the reactive power control instability dead zones of all wind turbine units), the reactive power control system can accurately distribute the farm-level dispatch command to each wind turbine unit, and the unit command response is precise, thereby achieving accurate control of reactive power at the farm level and meeting the grid dispatch requirements.
[0005] However, when the power grid dispatching authority issues a small reactive power dispatch command at the wind farm level (i.e., the reactive power of the dispatch command is less than the sum of the upper or lower limits of the unstable dead zones of reactive power control for all wind turbines), the shortcomings of the existing overall PI control method become apparent. In particular, when the reactive power control system allocates reactive power commands to a large number of wind turbines and enters the unstable range of turbine execution, the reactive power of the turbines will exhibit rapid jumps between positive and negative reactive power under the influence of the inductive or capacitive equipment of the turbines. This reactive power oscillation ultimately makes it difficult to accurately control the target reactive power at the wind farm level, resulting in the wind farm's outlet voltage not meeting the requirements of the power grid dispatching authority and affecting grid stability. Simultaneously, to compensate for insufficient reactive power control, the wind farm's SVG (Static Var Generator) equipment needs to bear more reactive power regulation load, increasing the operating burden and losses of the SVG equipment, reducing its service life, and also increasing the wind farm's operation and maintenance costs.
[0006] Furthermore, regarding reactive power control, patent document CN102299527A discloses a method and system for reactive power control in wind farms. This technology can ensure that the reactive power output at the wind farm's grid connection point meets the system's requirements, suppress bus voltage fluctuations, adjust the wind farm's power factor, and coordinate the reactive power output of each wind turbine and centralized reactive power compensation equipment within the wind farm. However, in-depth analysis reveals that this technology does not consider the farm-level control requirements under small reactive power dispatch commands, and it does not specifically address the unstable dead zone of wind turbine reactive power control or the impact of inductive and capacitive equipment in the turbines. It cannot solve the problems of unreasonable command allocation, wind turbine reactive power jumps, and overall reactive power oscillations under small reactive power dispatch targets. Therefore, it cannot achieve precise farm-level control of small reactive power and still cannot meet the grid's dispatch requirements for small-megawatt, older wind turbines under small reactive power scenarios. Summary of the Invention
[0007] This invention proposes a wind farm-level low reactive power control method and system, aiming to solve the technical problem of instability in existing wind farm-level reactive power control under low reactive power control scenarios.
[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A method for controlling low reactive power at the wind farm level includes the following steps: S1. Initialize the wind turbine power management system to a state where no reactive power command is sent to the wind turbine; S2. Calculate the average initial reactive power Q of all operating wind turbines in the wind farm. ave ; S3. Set the flow flag FistAvcControl of the control logic, and assign FistAvcControl=1 during the first control flow. S4. Obtain the scheduling command Q for the wind farm in the current control flow. p and determine the scheduling instruction Q p The entry condition for execution is in the scheduling instruction Q. p When the entry conditions are met, calculate the number of currently operating wind turbines, TurbNum_2, and switch to S5 if TurbNum_2≠0; S5. Determine the assignment status of FistAvcControl and, according to the scheduling instruction Q p and average initial reactive power Q ave Determine the number of fans participating in the adjustment under the corresponding assigned state of FistAvcControl; S6. Assign FistAvcControl=0, obtain the sign bit of the number of fans participating in the adjustment, calculate the fan reactive power setpoint avcPowerRef based on the sign bit; then set the number of fans that need to be temporarily adjusted TurbControlNum_Tmp=|TurbControlNum_1|, and initialize the number of fans executing avcPowerRef in the current control flow to wtbNum=0. S7. Arrange the wind turbines participating in the adjustment in sequence, and iterate through the status of all wind turbines. If the wind turbine is in normal power generation and the reactive power control function is enabled, continue to check whether wtbNum is less than TurbControlNum_Tmp. If it is less, check whether the wind farm has reactive power decoupling. If it does, increment the wtbNum variable by 1 and issue the reactive power setpoint avcPowerRef for that wind turbine. If it does not, continue to check whether the current active power P of the wind turbine is greater than 3*T. t If the conditions are met, the variable wtbNum is incremented by 1 and the reactive power setting value avcPowerRef for the wind turbine is issued. If the conditions are not met, the reactive power setting value for the wind turbine is set to 0. If wtbNum is greater than or equal to TurbControlNum_Tmp, the reactive power setting value for the wind turbine is set to 0. If the wind turbine is in an abnormal power generation state and the reactive power control function is enabled, the reactive power setting value for the wind turbine is set to 0. S8. The wind turbine power management system issues reactive power commands according to the control logic of S7 to complete one wind farm-level reactive power control process; then repeats S4-S8 to cyclically realize the wind farm-level reactive power control process.
[0009] In S2, the average initial reactive power value Q ave The calculation method is as follows: count the number of all operating wind turbines in the wind farm. If the number of all operating wind turbines is greater than 90% of the total number of wind turbines in the wind farm, then calculate the sum of the reactive power Q of all operating wind turbines in their initial state. sum And according to Q ave =Q sum The average initial reactive power value Q is calculated using / TurbNum_1. ave If the number of all operating generating wind turbines is less than 90% of the total number of wind turbines in the wind farm, then the historical stored value or the default average value will be used as the average initial reactive power value Q of the wind farm's wind turbines. ave .
[0010] In S3, the condition for assigning the process flag FistAvcControl=1 is: Q p >T t *TurbNum_1 or Q p <-T t *TurbNum_1 or |Q p -Qplast |>△Q;where, Q p This is the current control flow's wind farm scheduling instruction; Q plast Q is the scheduling instruction for the wind farm in the previous control process. p For the first control flow, Q plast The default value is 0; T t TurbNum_1 represents the dead zone for reactive power control in the wind farm; TurbNum_1 represents the number of currently operating wind turbines; △Q represents the reactive power regulation accuracy of the wind farm.
[0011] In S4, the entry condition for determining the execution of the scheduling instruction Qp is: (1), Q p <T t *TurbNum_1 or Q p >-T t *TurbNum_1; (2) Increase the control waiting time Time, and Time > Time p ; Where TurbNum_1 represents the number of currently operating wind turbines; T t Wind farm reactive power control dead zone, Time p This refers to the effective response feedback time of the wind turbine's reactive power.
[0012] In S5, the calculation method for the number of fans participating in regulation, TurbControlNum_1, is as follows: If FistAvcControl=1, then:
[0013] If FistAvcControl=0, then:
[0014] In any control flow other than the first one, the number of fans involved in the adjustment is the sum of the number of fans in the previous control flow and the number of fans in the current control flow.
[0015] In S6, the calculation method for the wind turbine reactive power setpoint avcPowerRef is as follows: avcPowerRef=sigTubNum*T t Wherein, sigTubNum is the sign bit of the number of fans involved in the regulation, and sigTubNum is +1 or -1.
[0016] In S7, the method for sequentially arranging the fans participating in the regulation is as follows: the fans participating in the regulation are sorted by number and stored in the list 'turbineMap', and a sequentially arranged loop is created according to the 'turbineMap' list.
[0017] A wind farm-level low reactive power control system, including Initialization module: Used to initialize the wind turbine power management system to a state where no reactive power command is sent to the wind turbine; Initial reactive power calculation module: Used to calculate the average initial reactive power Q of all operating wind turbines in the wind farm. ave ; Preset module: Used to set the flow flag FistAvcControl of the control logic, and assigns FistAvcControl=1 during the first control flow; Logic judgment module: Used to obtain the scheduling instruction Q of the wind farm in the current control flow. p and determine the scheduling instruction Q p The entry condition for execution is in the scheduling instruction Q. p When the entry condition is met, calculate the number of currently operating wind turbines, TurbNum_2, and when TurbNum_2≠0, proceed to the flag bit judgment module; Flag determination module: Used to determine the assignment status of FistAvcControl and according to the scheduling instruction Q. p and average initial reactive power Q ave Determine the number of fans participating in the adjustment under the corresponding assigned state of FistAvcControl; Assignment module: used to assign FistAvcControl=0, obtain the sign bit of the number of fans participating in the adjustment, calculate the fan reactive power setpoint avcPowerRef based on the sign bit; then set the number of fans that need to be temporarily adjusted TurbControlNum_Tmp=|TurbControlNum_1|, and initialize the number of fans executing avcPowerRef in the current control flow wtbNum=0. Logic module: Used to sequentially arrange the wind turbines participating in the regulation, traversing the status of all wind turbines. If the wind turbine is in normal power generation and reactive power control is enabled, it continues to check whether wtbNum is less than TurbControlNum_Tmp. If it is less, it checks whether the wind farm has reactive power decoupling. If it does, it increments the wtbNum variable by 1 and issues the reactive power setpoint avcPowerRef for that wind turbine. If it does not, it continues to check whether the current active power P of the wind turbine is greater than 3*T. tIf the conditions are met, the variable wtbNum is incremented by 1 and the reactive power setting value avcPowerRef for the wind turbine is issued. If the conditions are not met, the reactive power setting value for the wind turbine is set to 0. If wtbNum is greater than or equal to TurbControlNum_Tmp, the reactive power setting value for the wind turbine is set to 0. If the wind turbine is in an abnormal power generation state and the reactive power control function is enabled, the reactive power setting value for the wind turbine is set to 0. The loop module is used to enable the wind turbine power management system to issue reactive power commands according to the control logic of the logic module, complete one wind farm-level reactive power control process; then, it repeatedly executes the logic judgment module, flag judgment module, assignment module and logic module to loop through the wind farm-level reactive power control process.
[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. The method and system provided by this invention include a total of 8 processes, of which S1 and S2 The purpose of S3 is to increase the versatility of the system, ensuring that the system can be used in wind farms with different numbers of wind turbines, different wind turbine capacities, and different wind turbine states without being affected. The purpose of S4 is to avoid the problem of needing to make large-scale adjustments in every process cycle of the system. After the first instruction is issued, the reactive power adjustment only needs to be adjusted in small batches based on the results of the adjustment. This operation can effectively improve the stability of reactive power control in wind farms. The purpose of S4 and S5 is to calculate how reactive power needs to be adjusted under the current dispatch instruction. S4 sets a control waiting time. Since it takes a certain amount of time for the wind turbine to receive the reactive power setting instruction and for the system to complete the execution and detect the execution effect, this time varies from wind farm to wind farm. Therefore, adding this waiting time avoids the risk of increasing reactive power oscillation in wind farms due to multiple adjustments by the system in a short period of time. The cooperation of S4 and S5 helps to ensure the stable operation of reactive power in wind farms. The purpose of S6 and S7 is to distribute and calculate the final instruction issued by the system to the wind turbine. After accurately analyzing the reactive power available state of the wind farm's wind turbines, S7 reasonably issues the reactive power set value to the wind turbine, ensuring that the reactive power of the wind farm can accurately follow the dispatch instruction.
[0019] In summary, this invention, within the specified conditions, defines the control process cycle interval according to the response time of the data upload between the control system and the wind turbine. This effectively avoids power oscillations caused by issuing secondary control commands too quickly before the actual control effect is detected, thus improving the stability of existing wind farm-level reactive power control in low reactive power control scenarios.
[0020] 2. This invention can effectively utilize the uncontrolled reactive power generation of wind turbines to reduce the reactive power load of wind turbine converters in wind farms.
[0021] 3. The present invention adopts fixed sequence control. When the wind turbine status does not change, it avoids frequent changes in the controlled wind turbine object. Compared with the prior art, it improves the stability of the control and avoids the wind turbine converter frequently adjusting the output reactive power, further reducing the power generation load of the converter.
[0022] 4. Compared with existing general PI or PID regulation, the present invention, by adding small reactive power control logic and coordinating with conventional general control, can more accurately and quickly meet the reactive power output requirements of the power grid. Attached Figure Description
[0023] Figure 1 This is a flowchart of the present invention; Figure 2 This is a system block diagram of the present invention; Figure 3 This is a graph showing the reactive power control curve of a wind farm before its renovation in Example 3. Figure 4 This is a small reactive power control curve diagram after the wind farm was modified in Example 3. Detailed Implementation
[0024] The present invention will be further described below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
[0025] Example 1 See Figure 1 This embodiment provides a wind farm-level low reactive power control method, which is particularly suitable for the grid's dispatch requirements for low reactive power scenarios of small-megawatt old wind turbine units. The method specifically includes the following steps: S1. Initialize the wind turbine power management system to a state where no reactive power command is issued to the wind turbine.
[0026] S2. The average initial reactive power Q of all operating wind turbines in the wind farm is calculated by the wind turbine power management system. ave .
[0027] In this embodiment, the average initial reactive power value Q ave The calculation method is as follows: First, count the number of all operating wind turbines in the wind farm, and determine whether the number of all operating wind turbines is greater than 90% of the total number of wind turbines in the wind farm. If the number of all operating wind turbines is greater than 90% of the total number of wind turbines in the wind farm, then calculate the sum of the reactive power Q of all operating wind turbines in the initial state. sum And according to Q ave =Q sum The average initial reactive power value Q is calculated using / TurbNum_1. aveIf the number of all operating generating wind turbines is less than 90% of the total number of wind turbines in the wind farm, then the historical stored value or the default average value will be used as the average initial reactive power value Q of the wind farm's wind turbines. ave .
[0028] S3. Set the flow flag FistAvcControl of the control logic, and assign FistAvcControl=1 during the first control flow. In this embodiment, the condition for assigning the process flag FistAvcControl=1 is: Q p >T t *TurbNum_1 or Q p <-T t *TurbNum_1 or |Q p -Q plast |>△Q;where, Q p This is the current control flow's wind farm scheduling instruction; Q plast Q is the scheduling instruction for the wind farm in the previous control process. p For the first control flow, Q plast The default value is 0; T t TurbNum_1 represents the dead zone for reactive power control in the wind farm; TurbNum_1 represents the number of currently operating wind turbines; △Q represents the reactive power regulation accuracy of the wind farm.
[0029] S4. Obtain the scheduling command Q for the wind farm in the current control flow. p and determine the scheduling instruction Q p The entry condition for execution is in the scheduling instruction Q. p When the entry conditions are met, calculate the number of currently operating wind turbines, TurbNum_2, and switch to S5 when TurbNum_2≠0.
[0030] In this embodiment, the entry condition for determining the execution of the scheduling instruction Qp is: (1), Q p <T t *TurbNum_1 or Q p >-T t *TurbNum_1; (2) Increase the control waiting time Time, and Time > Time p ; Where TurbNum_1 represents the number of currently operating wind turbines; T t Wind farm reactive power control dead zone, Time p This refers to the effective response feedback time of the wind turbine's reactive power.
[0031] It should be noted that when TurbNum_2=0, it indicates that the scheduling instruction Q... pIf the conditions for execution are not met, the process continues until the scheduling instruction Q is reached. p The conditions for execution entry are met.
[0032] S5. Determine the assignment status of FistAvcControl and, according to the scheduling instruction Q p and average initial reactive power Q ave Determine the number of fans participating in the adjustment under the corresponding assigned state of FistAvcControl.
[0033] In this embodiment, FistAvcControl has two assignment states: one is to assign FistAvcControl=1, and the other is to assign FistAvcControl=0.
[0034] If FistAvcControl=1, the calculation method for the number of fans participating in the regulation, TurbControlNum_1, is as follows:
[0035] If FistAvcControl=0, the calculation method for the number of fans participating in the regulation, TurbControlNum_1, is as follows:
[0036] In any control flow other than the first one (when the flag FistAvcControl=0), the number of fans participating in the adjustment is the sum of the number of fans in the previous control flow and the number of fans in the current control flow.
[0037] After S6.S5 is completed, FistAvcControl=0 is assigned, the sign bit of the number of fans participating in the adjustment is obtained, and the reactive power setpoint avcPowerRef of the fans is calculated based on the sign bit; then the number of fans that need to be temporarily adjusted is set TurbControlNum_Tmp=|TurbControlNum_1|, and the number of fans executing avcPowerRef in the current control flow is initialized wtbNum=0.
[0038] In this embodiment, the calculation method for the wind turbine reactive power setpoint avcPowerRef is as follows: avcPowerRef=sigTubNum*T t Wherein, sigTubNum is the sign bit of the number of fans involved in the regulation, and sigTubNum is +1 or -1.
[0039] S7. Arrange the wind turbines participating in the regulation in sequence. Store the wind turbines in a fixed order by their numbers in a list `turbineMap`, and create a loop body arranged in sequence according to the `turbineMap` list. Then iterate through the status of all wind turbines. If the wind turbine is in normal power generation and reactive power control is enabled, continue to check if `wtbNum` is less than `TurbControlNum_Tmp`. If it is, check if the wind farm has reactive power decoupling. If it does, increment the `wtbNum` variable by 1 and issue the reactive power setpoint `avcPowerRef` for that wind turbine. If it does not, continue to check if the current active power P of the wind turbine is greater than 3*T. t If the conditions are met, the variable wtbNum is incremented by 1 and the reactive power setting value avcPowerRef for the wind turbine is issued. If the conditions are not met, the reactive power setting value for the wind turbine is set to 0. If wtbNum is greater than or equal to TurbControlNum_Tmp, the reactive power setting value for the wind turbine is set to 0. If the wind turbine is in an abnormal power generation state and the reactive power control function is enabled, the reactive power setting value for the wind turbine is set to 0.
[0040] S8. The wind turbine power management system issues reactive power commands according to the control logic of S7 to complete one wind farm-level reactive power control process; then repeats S4-S8 to cyclically realize the wind farm-level reactive power control process.
[0041] It should be noted that S1 and S2 run only once during the first control flow of the system, and the average initial reactive power value Q is calculated after the run. ave S1 and S2 are used until the system stops running, and will not be executed in subsequent control flows. S3 is only assigned the value FistAvcControl=1 in the first control flow. After being assigned the value FistAvcControl=0 in S6, S3 maintains the assigned value FistAvcControl=0 in subsequent control flows. S4 checks the execution entry condition in each control flow. S5-S8 will only run if the condition of S4 is met, thus achieving stable control with low reactive power.
[0042] This embodiment, through the control method of the above specific steps, can determine the cycle interval of the control process according to the response time of the data upload between the control system and the wind turbine within the range of conditions met. This effectively avoids the power oscillation caused by issuing secondary control commands too quickly and not detecting the actual control effect, thus making the existing wind farm-level reactive power control more stable in low reactive power control scenarios.
[0043] Example 2 See Figure 2 This embodiment provides a wind farm-level low reactive power control system, including... Initialization module: Used to initialize the wind turbine power management system to a state where no reactive power command is sent to the wind turbine; Initial reactive power calculation module: Used to calculate the average initial reactive power Q of all operating wind turbines in the wind farm. ave ; Preset module: Used to set the flow flag FistAvcControl of the control logic, and assigns FistAvcControl=1 during the first control flow; Logic judgment module: Used to obtain the scheduling instruction Q of the wind farm in the current control flow. p and determine the scheduling instruction Q p The entry condition for execution is in the scheduling instruction Q. p When the entry condition is met, calculate the number of currently operating wind turbines, TurbNum_2, and when TurbNum_2≠0, proceed to the flag bit judgment module; Flag determination module: Used to determine the assignment status of FistAvcControl and according to the scheduling instruction Q. p and average initial reactive power Q ave Determine the number of fans participating in the adjustment under the corresponding assigned state of FistAvcControl; Assignment module: used to assign FistAvcControl=0, obtain the sign bit of the number of fans participating in the adjustment, calculate the fan reactive power setpoint avcPowerRef based on the sign bit; then set the number of fans that need to be temporarily adjusted TurbControlNum_Tmp=|TurbControlNum_1|, and initialize the number of fans executing avcPowerRef in the current control flow wtbNum=0. Logic module: Used to sequentially arrange the wind turbines participating in the regulation, traversing the status of all wind turbines. If the wind turbine is in normal power generation and reactive power control is enabled, it continues to check whether wtbNum is less than TurbControlNum_Tmp. If it is less, it checks whether the wind farm has reactive power decoupling. If it does, it increments the wtbNum variable by 1 and issues the reactive power setpoint avcPowerRef for that wind turbine. If it does not, it continues to check whether the current active power P of the wind turbine is greater than 3*T. t If the conditions are met, the variable wtbNum is incremented by 1 and the reactive power setting value avcPowerRef for the wind turbine is issued. If the conditions are not met, the reactive power setting value for the wind turbine is set to 0. If wtbNum is greater than or equal to TurbControlNum_Tmp, the reactive power setting value for the wind turbine is set to 0. If the wind turbine is in an abnormal power generation state and the reactive power control function is enabled, the reactive power setting value for the wind turbine is set to 0. The loop module is used to enable the wind turbine power management system to issue reactive power commands according to the control logic of the logic module, complete one wind farm-level reactive power control process; then, it repeatedly executes the logic judgment module, flag judgment module, assignment module and logic module to loop through the wind farm-level reactive power control process.
[0044] In detail, based on the same innovative concept, each module in the system described in this embodiment adopts the same technical means as in Embodiment 1 when used, and can produce the same technical effect, which will not be repeated here.
[0045] Experimental Example This experimental example verifies the control method of Example 1, as detailed below: 1. See Figure 3 A certain wind farm has 25 turbine units, with a total installed capacity of 50MW. Figure 3 The actual operation of the wind farm before the small reactive power control modification is shown. When the reactive power dispatch command is small, the reactive power of the wind farm fluctuates frequently above and below the dispatch command. The maximum reactive power is 1146.9 Kvar, which clearly reflects the poor stability of small reactive power control.
[0046] 2. See Figure 4 , Figure 4 The operation of the small reactive power command after modification using the control method of Example 1 is shown. The comparison shows that the reactive power control of the wind farm is significantly improved after modification. The maximum reactive power deviation of the selected data segment is only 391 kvar. This proves that the small reactive power control method provided by the present invention improves the control accuracy of small reactive power and the stability of wind farm reactive power control.
[0047] The above description is merely a specific embodiment of the present invention. Any feature disclosed in this specification may be replaced by other equivalent features unless otherwise specified. All features or steps in all methods or processes disclosed may be combined in any way, except for mutually exclusive features and / or steps.
Claims
1. A method for controlling low reactive power at the wind farm level, characterized in that... Includes the following steps: S1. Initialize the wind turbine power management system to a state where no reactive power command is sent to the wind turbine; S2. Calculate the average initial reactive power Q of all operating wind turbines in the wind farm. ave ; S3. Set the flow flag FistAvcControl of the control logic, and assign FistAvcControl=1 during the first control flow. S4. Obtain the scheduling command Q for the wind farm in the current control flow. p and determine the scheduling instruction Q p The entry condition for execution is in the scheduling instruction Q. p When the entry conditions are met, calculate the number of currently operating wind turbines, TurbNum_2, and switch to S5 if TurbNum_2≠0; S5. Determine the assignment status of FistAvcControl and, according to the scheduling instruction Q p and average initial reactive power Q ave Determine the number of fans participating in the adjustment under the corresponding assigned state of FistAvcControl; S6. Assign FistAvcControl=0, obtain the sign bit of the number of fans participating in the adjustment, calculate the fan reactive power setpoint avcPowerRef based on the sign bit; then set the number of fans that need to be temporarily adjusted TurbControlNum_Tmp=|TurbControlNum_1|, and initialize the number of fans executing avcPowerRef in the current control flow to wtbNum=0. S7. Arrange the wind turbines participating in the adjustment in sequence, and iterate through the status of all wind turbines. If the wind turbine is in normal power generation and the reactive power control function is enabled, continue to check whether wtbNum is less than TurbControlNum_Tmp. If it is less, check whether the wind farm has reactive power decoupling. If it does, increment the wtbNum variable by 1 and issue the reactive power setpoint avcPowerRef for that wind turbine. If it does not, continue to check whether the current active power P of the wind turbine is greater than 3*T. t If the conditions are met, the variable wtbNum is incremented by 1 and the reactive power setting value avcPowerRef for the wind turbine is issued. If the conditions are not met, the reactive power setting value for the wind turbine is set to 0. If wtbNum is greater than or equal to TurbControlNum_Tmp, the reactive power setting value for the wind turbine is set to 0. If the wind turbine is in an abnormal power generation state and the reactive power control function is enabled, the reactive power setting value for the wind turbine is set to 0. S8. The wind turbine power management system issues reactive power commands according to the control logic of S7 to complete one wind farm-level reactive power control process; then repeats S4-S8 to cyclically realize the wind farm-level reactive power control process.
2. The wind farm-level low reactive power control method according to claim 1, characterized in that: In S2, the average initial reactive power value Q ave The calculation method is as follows: count the number of all operating wind turbines in the wind farm. If the number of all operating wind turbines is greater than 90% of the total number of wind turbines in the wind farm, then calculate the sum of the reactive power Q of all operating wind turbines in their initial state. sum And according to Q ave =Q sum The average initial reactive power value Q is calculated using / TurbNum_1. ave If the number of all operating generating wind turbines is less than 90% of the total number of wind turbines in the wind farm, then the historical stored value or the default average value will be used as the average initial reactive power value Q of the wind farm's wind turbines. ave .
3. The wind farm-level low reactive power control method according to claim 1, characterized in that: In S3, the condition for assigning the process flag FistAvcControl=1 is: Q p >T t *TurbNum_1 or Q p <-T t *TurbNum_1 or |Q p -Q plast |>△Q;where, Q p This is the current control flow's wind farm scheduling instruction; Q plast Q is the scheduling instruction for the wind farm in the previous control process. p For the first control flow, Q plast The default value is 0; T t TurbNum_1 represents the dead zone for reactive power control in the wind farm; TurbNum_1 represents the number of currently operating wind turbines; △Q represents the reactive power regulation accuracy of the wind farm.
4. The wind farm-level low reactive power control method according to claim 1, characterized in that: In S4, the entry condition for determining the execution of the scheduling instruction Qp is: (1), Q p <T t *TurbNum_1 or Q p >-T t *TurbNum_1; (2) Increase the control waiting time Time, and Time > Time p ; Where TurbNum_1 represents the number of currently operating wind turbines; T t Wind farm reactive power control dead zone, Time p This refers to the effective response feedback time of the wind turbine's reactive power.
5. The wind farm-level low reactive power control method according to claim 1, characterized in that: In S5, the calculation method for the number of fans participating in regulation, TurbControlNum_1, is as follows: If FistAvcControl=1, then: If FistAvcControl=0, then: In any control flow other than the first one, the number of fans involved in the adjustment is the sum of the number of fans in the previous control flow and the number of fans in the current control flow.
6. The wind farm-level low reactive power control method according to claim 1, characterized in that: In S6, the calculation method for the wind turbine reactive power setpoint avcPowerRef is as follows: avcPowerRef=sigTubNum*T t Wherein, sigTubNum is the sign bit of the number of fans involved in the regulation, and sigTubNum is +1 or -1.
7. The wind farm-level low reactive power control method according to claim 1, characterized in that: In S7, the method for sequentially arranging the fans participating in the regulation is as follows: the fans participating in the regulation are sorted by number and stored in the list 'turbineMap', and a sequentially arranged loop is created according to the 'turbineMap' list.
8. A wind farm-level low reactive power control system, characterized in that... include: Initialization module: Used to initialize the wind turbine power management system to a state where no reactive power command is sent to the wind turbine; Initial reactive power calculation module: Used to calculate the average initial reactive power Q of all operating wind turbines in the wind farm. ave ; Preset module: Used to set the flow flag FistAvcControl of the control logic, and assigns FistAvcControl=1 during the first control flow; Logic judgment module: Used to obtain the scheduling instruction Q of the wind farm in the current control flow. p and determine the scheduling instruction Q p The entry condition for execution is in the scheduling instruction Q. p When the entry condition is met, calculate the number of currently operating wind turbines, TurbNum_2, and when TurbNum_2≠0, proceed to the flag bit judgment module; Flag determination module: Used to determine the assignment status of FistAvcControl and according to the scheduling instruction Q. p and average initial reactive power Q ave Determine the number of fans participating in the adjustment under the corresponding assigned state of FistAvcControl; Assignment module: used to assign FistAvcControl=0, obtain the sign bit of the number of fans participating in the adjustment, calculate the fan reactive power setpoint avcPowerRef based on the sign bit; then set the number of fans that need to be temporarily adjusted TurbControlNum_Tmp=|TurbControlNum_1|, and initialize the number of fans executing avcPowerRef in the current control flow wtbNum=0. Logic module: Used to sequentially arrange the wind turbines participating in the regulation, traversing the status of all wind turbines. If the wind turbine is in normal power generation and reactive power control is enabled, it continues to check whether wtbNum is less than TurbControlNum_Tmp. If it is less, it checks whether the wind farm has reactive power decoupling. If it does, it increments the wtbNum variable by 1 and issues the reactive power setpoint avcPowerRef for that wind turbine. If it does not, it continues to check whether the current active power P of the wind turbine is greater than 3*T. t If the conditions are met, the variable wtbNum is incremented by 1 and the reactive power setting value avcPowerRef for the wind turbine is issued. If the conditions are not met, the reactive power setting value for the wind turbine is set to 0. If wtbNum is greater than or equal to TurbControlNum_Tmp, the reactive power setting value for the wind turbine is set to 0. If the wind turbine is in an abnormal power generation state and the reactive power control function is enabled, the reactive power setting value for the wind turbine is set to 0. The loop module is used to enable the wind turbine power management system to issue reactive power commands according to the control logic of the logic module, complete one wind farm-level reactive power control process; then, it repeatedly executes the logic judgment module, flag judgment module, assignment module and logic module to loop through the wind farm-level reactive power control process.
Citation Information
Patent Citations
A method and system for reactive power control in wind farms
CN102299527A