Reactive power control method and device for fan group

Abstract

Provided are a reactive power control method and device for a wind turbine group. The reactive power control method for the wind turbine group comprises: obtaining a total reactive power demand value required by a power grid for the wind turbine group to reach and a total actual reactive power value of the wind turbine group; inputting the total reactive power demand value into a feedforward controller to obtain a first reactive power target value output by the feedforward controller; inputting a difference between the total reactive power demand value and the total actual reactive power value into a PI controller to obtain a second reactive power target value output by the PI controller; determining a total reactive power target value of the wind turbine group based on the first reactive power target value and the second reactive power target value; and determining a reactive power target value of each wind turbine generator set in the wind turbine group based on the total reactive power target value.

Description

Technical Field

[0001] This disclosure generally relates to the field of power technology, and more specifically, to a method and apparatus for reactive power control of a wind turbine group. Background Technology

[0002] With the introduction of the "dual carbon" target, new energy sources will gradually become the main power source in the entire power system. Under the new power system, higher requirements will inevitably be placed on the grid-friendliness of new energy power plants, and the reactive power and voltage control of new energy power plants will therefore become more important.

[0003] Reactive power and voltage control in renewable energy power plants typically involves several stages. First, a reactive power and voltage control (AVC) substation system is installed at the power plant to receive reactive power and voltage dispatch commands from the power grid and then distributes the final reactive power commands to each controlled reactive power unit through control calculations. In actual engineering projects, the power plant's reactive power and voltage control substation often cannot communicate directly with the wind turbine generators (hereinafter referred to as wind turbines or wind turbine units). Therefore, reactive power control of the wind farm group is often handled by the wind turbine group controller, such as... Figure 1 As shown, after the wind turbine group controller receives the reactive power command from the power plant's reactive power and voltage control system, it calculates the command using a specific allocation strategy and then sends it to the wind turbine generators. Upon receiving the reactive power command, the wind turbine generators perform a rapid closed-loop response to achieve the final reactive power and voltage control target at the power plant end. Therefore, the quality of the wind turbine group controller's control directly affects the overall reactive power and voltage control effect. Selecting appropriate control methods and strategies plays a crucial role in achieving the overall reactive power and voltage control target and improving the grid connection characteristics of renewable energy power plants. Summary of the Invention

[0004] An exemplary embodiment of this disclosure provides a reactive power control method and apparatus for a wind turbine group, which can effectively and reasonably control the reactive power of the wind turbine group to meet the grid demand.

[0005] According to a first aspect of the present disclosure, a reactive power control method for a wind turbine group is provided, comprising: obtaining a total reactive power demand value required by the power grid for the wind turbine group and an actual total reactive power value of the wind turbine group; inputting the total reactive power demand value into a feedforward controller to obtain a first reactive power target value output by the feedforward controller; inputting the difference between the total reactive power demand value and the actual total reactive power value into a PI controller to obtain a second reactive power target value output by the PI controller; determining a total reactive power target value for the wind turbine group based on the first reactive power target value and the second reactive power target value; and determining a reactive power target value for each wind turbine generator unit in the wind turbine group based on the total reactive power target value.

[0006] Optionally, the PI controller is an anti-integral saturation PI controller, wherein the reactive power control method further includes: setting an upper limit value and a lower limit value of the saturation limit of the anti-integral saturation module of the PI controller based on the feedforward coefficient of the feedforward controller.

[0007] Optionally, the step of setting the upper limit and lower limit of the saturation limit of the anti-integral saturation module of the PI controller based on the feedforward coefficient of the feedforward controller includes: when the feedforward coefficient is 1, setting the upper limit of the saturation limit to the sum of the reactive power control accuracy of each wind turbine generator set, and setting the lower limit of the saturation limit to the negative of the sum of the reactive power control accuracy of each wind turbine generator set.

[0008] Optionally, the step of setting the upper and lower limits of the saturation limit of the anti-integral saturation module of the PI controller based on the feedforward coefficient of the feedforward controller includes: when the feedforward coefficient is not 1, setting the upper limit of the saturation limit based on the sum of the reactive power control accuracy of each wind turbine generator set, the total capacitive reactive power limit of the wind turbine group, and the feedforward coefficient; and setting the lower limit of the saturation limit based on the negative number of the sum of the reactive power control accuracy of each wind turbine generator set, the total inductive reactive power limit of the wind turbine group, and the feedforward coefficient.

[0009] Optionally, the step of determining the total reactive power target value of the wind turbine group based on the first reactive power target value and the second reactive power target value includes: performing a limiting process on the sum of the first reactive power target value and the second reactive power target value, and using the result of the limiting process as the total reactive power target value of the wind turbine group, wherein the upper limit of the limiting process is the total capacitive reactive power limit value of the wind turbine group, and the lower limit of the limiting process is the total inductive reactive power limit value of the wind turbine group.

[0010] Optionally, the step of determining the reactive power target value of each wind turbine generator set in the wind turbine group based on the total reactive power target value includes: when the total reactive power target value is greater than 0, for each wind turbine generator set, the product of the capacitive reactive power limit of the wind turbine generator set and a first proportional coefficient is determined as the reactive power target value of the wind turbine generator set; when the total reactive power target value is less than 0, for each wind turbine generator set, the product of the inductive reactive power limit of the wind turbine generator set and a second proportional coefficient is determined as the reactive power target value of the wind turbine generator set; wherein, the first proportional coefficient is the ratio of the total reactive power target value to the total capacitive reactive power limit of the wind turbine group; and the second proportional coefficient is the ratio of the total reactive power target value to the total inductive reactive power limit of the wind turbine group.

[0011] Optionally, the reactive power control method further includes: obtaining the actual reactive power value, capacitive reactive power limit, and inductive reactive power limit of each wind turbine generator set; determining the total actual reactive power value of the wind turbine group as the sum of the actual reactive power values ​​of each wind turbine generator set; determining the total capacitive reactive power limit of the wind turbine group as the sum of the capacitive reactive power limit of each wind turbine generator set; and determining the total inductive reactive power limit of the wind turbine group as the sum of the inductive reactive power limit of each wind turbine generator set.

[0012] According to a second aspect of the present disclosure, a reactive power control device for a wind turbine group is provided, comprising: a data acquisition unit configured to acquire a total reactive power demand value required by the power grid for the wind turbine group and an actual total reactive power value of the wind turbine group; a feedforward control unit configured to input the total reactive power demand value into a feedforward controller to obtain a first reactive power target value output by the feedforward controller; a closed-loop control unit configured to input the difference between the total reactive power demand value and the actual total reactive power value into a PI controller to obtain a second reactive power target value output by the PI controller; a total target value determination unit configured to determine the total reactive power target value of the wind turbine group based on the first and second reactive power target values; and a single-unit target value determination unit configured to determine the reactive power target value of each wind turbine generator unit in the wind turbine group based on the total reactive power target value.

[0013] Optionally, the PI controller is an anti-integral saturation PI controller, wherein the reactive power control device further includes: a saturation limit setting unit, configured to set the upper limit and lower limit of the saturation limit of the anti-integral saturation module of the PI controller based on the feedforward coefficient of the feedforward controller.

[0014] Optionally, the saturation limit setting unit is configured to: when the feedforward coefficient is 1, set the upper limit of the saturation limit to the sum of the reactive power control accuracy of each wind turbine generator set, and set the lower limit of the saturation limit to the negative of the sum of the reactive power control accuracy of each wind turbine generator set.

[0015] Optionally, the saturation limit setting unit is configured to: when the feedforward coefficient is not 1, set the upper limit of the saturation limit based on the sum of the reactive power control accuracy of each wind turbine generator set, the total capacitive reactive power limit of the wind turbine group, and the feedforward coefficient; and set the lower limit of the saturation limit based on the negative number of the sum of the reactive power control accuracy of each wind turbine generator set, the total inductive reactive power limit of the wind turbine group, and the feedforward coefficient.

[0016] Optionally, the total target value determination unit is configured to: perform a limiting process on the sum of the first reactive power target value and the second reactive power target value, and use the result of the limiting process as the total reactive power target value of the wind turbine group, wherein the upper limit of the limiting process is the total capacitive reactive power limit of the wind turbine group, and the lower limit of the limiting process is the total inductive reactive power limit of the wind turbine group.

[0017] Optionally, the single-unit target value determination unit is configured to: when the total reactive power target value is greater than 0, for each of the wind turbine generator sets, determine the reactive power target value of that wind turbine generator set by multiplying the capacitive reactive power limit of that wind turbine generator set by a first proportional coefficient; when the total reactive power target value is less than 0, for each of the wind turbine generator sets, determine the reactive power target value of that wind turbine generator set by multiplying the inductive reactive power limit of that wind turbine generator set by a second proportional coefficient; wherein, the first proportional coefficient is the ratio of the total reactive power target value to the total capacitive reactive power limit of the wind turbine group; and the second proportional coefficient is the ratio of the total reactive power target value to the total inductive reactive power limit of the wind turbine group.

[0018] Optionally, the data acquisition unit is configured to: acquire the actual reactive power value, capacitive reactive power limit value, and inductive reactive power limit value of each wind turbine generator set; determine the total actual reactive power value of the wind turbine group as the sum of the actual reactive power values ​​of each wind turbine generator set; determine the total capacitive reactive power limit value of the wind turbine group as the sum of the capacitive reactive power limit values ​​of each wind turbine generator set; and determine the total inductive reactive power limit value of the wind turbine group as the sum of the inductive reactive power limit values ​​of each wind turbine generator set.

[0019] Optionally, the reactive power control device is installed in the wind turbine group controller, which is electrically connected to the main controller of each wind turbine generator set in the wind turbine group and the wind farm controller; the wind farm controller is used to send the total reactive power demand value; or, the reactive power control device is installed in the wind farm controller, which is electrically connected to the main controller of each wind turbine generator set in the wind turbine group.

[0020] According to a third aspect of the present disclosure, a computer-readable storage medium storing a computer program is provided, which, when executed by a processor, causes the processor to perform the reactive power control method for a wind turbine group as described above.

[0021] According to a fourth aspect of the present disclosure, a reactive power control device for a wind turbine group is provided. The reactive power control device includes: a processor; and a memory storing a computer program, wherein when the computer program is executed by the processor, it causes the processor to execute the reactive power control method for the wind turbine group as described above.

[0022] Optionally, the reactive power control device is installed in the wind turbine group controller, which is electrically connected to the main controller of each wind turbine generator set in the wind turbine group and the wind farm controller; the wind farm controller is used to send the total reactive power demand value; or, the reactive power control device is installed in the wind farm controller, which is electrically connected to the main controller of each wind turbine generator set in the wind turbine group.

[0023] The reactive power control method and apparatus for wind turbine groups according to the exemplary embodiments of this disclosure adopt a reactive power control method that combines reactive power command feedforward control with PI-based fast closed-loop control, which has the advantages of fast control speed and good fluctuation suppression performance.

[0024] Furthermore, the reactive power control method and apparatus for wind turbine groups according to the exemplary embodiments of this disclosure also provide a method for calculating the PI saturation limit, which can improve the PI anti-saturation capability, thereby further improving the reliability and stability of reactive power control.

[0025] Further aspects and / or advantages of the general concept of this disclosure will be set forth in part in the description which follows, and in part will be clear from the description or may be learned by practice of the general concept of this disclosure. Attached Figure Description

[0026] The above and other objects and features of exemplary embodiments of this disclosure will become clearer from the following description taken in conjunction with the accompanying drawings, which exemplarily illustrate the embodiments, wherein:

[0027] Figure 1 The topology of a power station reactive voltage integrated control system according to an exemplary embodiment of the present disclosure is shown.

[0028] Figure 2 A flowchart illustrating a reactive power control method for a wind turbine group according to an exemplary embodiment of the present disclosure is shown.

[0029] Figure 3 A control logic diagram of a reactive power control method for a wind turbine group according to an exemplary embodiment of the present disclosure is shown.

[0030] Figure 4 A flowchart illustrating a reactive power control method for a wind turbine group according to another exemplary embodiment of the present disclosure;

[0031] Figure 5A structural block diagram of a reactive power control device for a wind turbine group according to an exemplary embodiment of the present disclosure is shown.

[0032] Figure 6 A structural block diagram of a wind turbine group controller according to an exemplary embodiment of the present disclosure is shown. Detailed Implementation

[0033] The embodiments of this disclosure will now be described in detail with reference to the accompanying drawings, examples of which are illustrated in the drawings, wherein the same reference numerals always refer to the same parts. The embodiments will now be described with reference to the accompanying drawings in order to explain this disclosure.

[0034] Figure 2 A flowchart illustrating a reactive power control method for a wind turbine group according to an exemplary embodiment of the present disclosure is shown.

[0035] As an example, the reactive power control method for a wind turbine group according to an exemplary embodiment of the present disclosure can be executed by a wind turbine group controller, for example, the wind turbine group controller can be a wind farm controller.

[0036] As an example, the wind turbine group may consist of all the wind turbine generators within the wind farm, or it may consist of some of the wind turbine generators within the wind farm. In other words, a wind farm may include at least one wind turbine group, and each wind turbine group may include at least one wind turbine generator.

[0037] Reference Figure 2 And can be combined Figure 3 In step S101, the total reactive power demand value required by the power grid for the wind turbine group and the actual total reactive power value of the wind turbine group are obtained.

[0038] As an example, the reactive power command value Q can be received from the power station's AVC system in response to the power grid's reactive power dispatch command. set The received reactive power command value Q set A limiting process is applied, and the result of this limiting process is the total reactive power demand that the power grid requires from the wind turbine group. For example, the upper limit value of this limiting process is Q. max This can be the upper limit of the total theoretical non-functional capacity of the wind turbine group or the upper limit of the current total actual non-functional capacity of the wind turbine group; the lower limit of the limiting process is Q. min It can be the lower limit of the total theoretical non-functional capacity of the wind turbine group or the lower limit of the current total actual non-functional capacity of the wind turbine group.

[0039] For example, the upper limit of the total theoretical reactive power capacity of a wind turbine cluster can refer to the sum of the upper limits of reactive power capacity of all wind turbine generators in the cluster; while the current upper limit of the total actual reactive power capacity of the wind turbine cluster can refer to the sum of the upper limits of reactive power capacity of the currently reactive-controlled wind turbine generators in the cluster. For example, the lower limit of the total theoretical reactive power capacity of a wind turbine cluster can refer to the sum of the lower limits of reactive power capacity of all wind turbine generators in the cluster; while the current lower limit of the total actual reactive power capacity of the wind turbine cluster can refer to the sum of the lower limits of reactive power capacity of the currently reactive-controlled wind turbine generators in the cluster. For example, the currently reactive-controlled wind turbine generators can be the wind turbine generators that are currently operating normally.

[0040] For example, the upper limit of the total reactive power of a wind turbine group can be: the limit of the total capacitive reactive power of the wind turbine group; the upper limit of the reactive power of a wind turbine generator can be: the limit of the capacitive reactive power of the wind turbine generator. For example, the lower limit of the total reactive power of a wind turbine group can be: the limit of the total inductive reactive power of the wind turbine group; the lower limit of the reactive power of a wind turbine generator can be: the limit of the inductive reactive power of the wind turbine generator.

[0041] Furthermore, as another example, the reactive power command value issued by the wind turbine group in response to the reactive power dispatch command from the power station AVC system can be received and directly used as the total reactive power demand value that the power grid requires for the wind turbine group. For example, the power station AVC system can limit the reactive power dispatch command value from the power grid according to the total theoretical reactive power capacity limit of the wind turbine group to obtain the reactive power command value and issue it.

[0042] As an example, the actual total reactive power Q of this wind turbine group meas This can be the sum of the actual reactive power values ​​of all wind turbine generators in the wind turbine group. For example, here, each wind turbine generator can refer to the wind turbine generators in the wind turbine group whose reactive power is currently controlled.

[0043] As an example, prior to step S101, the reactive power control method for a wind turbine group according to an exemplary embodiment of this disclosure may further include: acquiring the actual reactive power value, capacitive reactive power limit, and inductive reactive power limit of each wind turbine generator set in the wind turbine group. For example, here, each wind turbine generator set may refer to the wind turbine generator sets in the wind turbine group whose reactive power is currently controlled. For example, the actual reactive power value, capacitive reactive power limit, and inductive reactive power limit reported by each wind turbine generator set may be received.

[0044] Then, the total reactive power of the wind turbine group can be determined as the sum of the actual reactive power of each wind turbine generator set; the total capacitive reactive power limit of the wind turbine group can be determined as the sum of the capacitive reactive power limits of each wind turbine generator set; and the total inductive reactive power limit of the wind turbine group can be determined as the sum of the inductive reactive power limits of each wind turbine generator set.

[0045] In step S102, the total reactive power demand value is input into the feedforward controller to obtain the first reactive power target value output by the feedforward controller.

[0046] As an example, the filtered total reactive power demand value can be input into the feedforward controller. For example, such as... Figure 3 As shown, the inertial time constant T used for filtering can be set according to the actual situation and requirements. Qset .

[0047] As an example, the feedforward coefficient K of the feedforward controller can be related to the reactive power performance of the wind turbine generators in the wind turbine group. It can be set according to the actual situation and specific needs, and the value range can be 0≤K≤1.0. For example, the reactive power performance of the wind turbine generators can include: reactive power control accuracy.

[0048] In step S103, the difference between the total reactive power demand value and the actual total reactive power value is input into the PI controller to obtain the second reactive power target value output by the PI controller.

[0049] As an example, the difference between the filtered total reactive power demand value and the filtered actual total reactive power value can be input into the PI controller to obtain the second reactive power target value output by the PI controller. For example, as... Figure 3 As shown, the inertial time constant T used for filtering the actual value of total reactive power can be set according to actual conditions and needs. Qmeas .

[0050] As an example, the PI controller used could be a PI controller with anti-integral saturation. For example, the PI controller could be as follows: Figure 3 As shown, K p T represents the proportionality coefficient; p T represents the time constant of the proportional portion of inertia. i Q represents the integral constant; TMAXOFFSET This indicates the upper limit of PI control saturation; Q TMINOFFSET K represents the lower limit of PI control saturation; anti This represents the feedback coefficient.

[0051] As an example, the reactive power control method for a wind turbine group according to an exemplary embodiment of this disclosure may further include: before step S103, setting an upper limit and a lower limit of the saturation limit of the anti-integral saturation module of the PI controller based on the feedforward coefficients of the feedforward controller. Further, as an example, the upper limit and lower limit of the saturation limit of the anti-integral saturation module of the PI controller may be set based on the feedforward coefficients of the feedforward controller, the reactive power control accuracy and / or reactive power capacity of each wind turbine generator set.

[0052] As an example, when the feedforward coefficient of the feedforward controller is 1, the upper limit value of the saturation limit Q can be set. TMAXOFFSET Set to the sum of reactive power control accuracy of each wind turbine generator set, and set the lower limit of saturation limit Q. TMINOFFSET Set to the negative of the sum of the reactive power control accuracy of each wind turbine generator set.

[0053] For example, when the feedforward coefficient is 1, the upper limit value of the saturation limit Q can be calculated using equation (1). TMAXOFFSET The lower limit value Q of the saturation limit is calculated using equation (2). TMINOFFSET .

[0054]

[0055]

[0056] Where 0≤Q j_error Q j_error The value represents the reactive power control accuracy of the j-th wind turbine generator set, N represents the total number of wind turbine generator sets, and j represents the index number of the wind turbine generator set.

[0057] As an example, the reactive power control accuracy of a wind turbine generator set can also be understood as the reactive power command execution accuracy, reactive power command response accuracy, reactive power command control deviation, and reactive power command execution deviation. For example, the reactive power control accuracy of a wind turbine generator set can be defined as the rated power P of the wind turbine generator set. n 1%.

[0058] As an example, when the feedforward coefficient of the feedforward controller is not 1, the upper limit of the saturation limit can be set based on the sum of the reactive power control accuracy of each wind turbine generator set, the total capacitive reactive power limit of the wind turbine group, and the feedforward coefficient; and the lower limit of the saturation limit can be set based on the negative number of the sum of the reactive power control accuracy of each wind turbine generator set, the total inductive reactive power limit of the wind turbine group, and the feedforward coefficient.

[0059] For example, when the feedforward coefficient is not 1.0, the execution deviation caused by the feedforward instruction needs to be considered. The upper limit value of the saturation limit Q can be calculated by equation (3). TMAXOFFSET The lower limit value Q of the saturation limit is calculated using equation (4).TMINOFFSET .

[0060]

[0061]

[0062] Among them, Q TMAXWF ≥0 indicates the total capacitive residual capacity limit of the wind turbine group, specifically the sum of the capacitive residual capacity limits of each individual unit. Q capj Q represents the capacitive non-functional limit of the j-th unit; TMINWF ≤0 indicates the total inductive dynamic capacity limit of the wind turbine group, specifically the sum of the inductive dynamic capacity limits of each individual turbine unit. Q indj This represents the inductive non-functional limit of the j-th generator unit; 0 ≤ Q j_error Q j_error The value represents the reactive power control accuracy of the j-th wind turbine generator set, N represents the total number of wind turbine generator sets, j represents the index number of the wind turbine generator set, and K represents the feedforward coefficient of the feedforward controller.

[0063] In step S104, the total reactive power target value of the wind turbine group is determined based on the first reactive power target value and the second reactive power target value.

[0064] As an example, the sum of the first and second reactive power target values ​​can be limited, and the result of the limiting process can be used as the total reactive power target value for the wind turbine group. For example, the upper limit value Q of this limiting process can be... TMAXWF This can be the total capacitive non-functional capacity limit of the wind turbine group, and the lower limit of the limiting treatment is Q. TMINWF This can be the limit of the total inductive non-functional capacity of the wind turbine group.

[0065] According to an exemplary embodiment of this disclosure, a command feedforward method is proposed to directly distribute the reactive power commands received by the group controller to the generating units according to a certain allocation method. Under normal circumstances, after the generating units execute the commands, the deviation between the overall reactive power commands and the actual reactive power output of the group is the total command difference caused by the reactive power accuracy deviation of each generating unit in the group. Therefore, the deviation between the reactive power commands and the actual reactive power output can be used as input for PI control. At this time, the upper and lower limits of PI control can be set by comprehensively considering the reactive power accuracy deviation of the group and the feedforward coefficient. The reactive power accuracy of the generating units is generally high, according to the standard NBT The "Technical Requirements and Test Procedures for Reactive Power Voltage Regulation of Wind Turbine Units (10314-2019)" requires that the voltage regulation should generally be within 2% of Pn. Therefore, the overall limit value is much smaller than the sum of reactive power capacity of traditional turbine groups. In this way, when the reactive power output of the unit is limited by safety constraints, the sum of the PI control command and the feedforward command will always be within a reasonable range. This allows the overall control to operate stably and smoothly under both normal and abnormal unit response conditions, greatly reducing reactive power fluctuations and effectively solving the problem of reactive power fluctuations caused by integral oversaturation.

[0066] In step S105, based on the total reactive power target value of the wind turbine group, the reactive power target value of each wind turbine generator is determined.

[0067] As an example, the target value of the total reactive power of the wind turbine group and the total reactive power capacity Q of the wind turbine group can be used as a basis. total (That is, the total reactive power limit of the wind turbine group), determine the reactive power command coefficient Q of the wind turbine. cmdf , this coefficient Q cmdf Multiplying this by the reactive power limit of the wind turbine generator yields the actual reactive power command value (i.e., the reactive power target value) for that wind turbine generator. For example, Q cmdf This can be expressed as the target value of the total reactive power of the wind turbine group divided by the total reactive power capacity Q of the wind turbine group. total .

[0068] As an example, when the total reactive power target value is greater than 0, for each wind turbine generator set among those currently under reactive power control, the product of the capacitive reactive power limit of that wind turbine generator set and a first proportional coefficient can be used to determine the reactive power target value of that wind turbine generator set. The first proportional coefficient is the ratio of the total reactive power target value of the wind turbine group to the total capacitive reactive power limit of the wind turbine group.

[0069] As an example, when the total reactive power target value is less than 0, for each wind turbine generator set among those currently under reactive power control, the product of the inductive reactive power limit of that wind turbine generator set and the second proportional coefficient can be used to determine the reactive power target value of that wind turbine generator set. The second proportional coefficient is the ratio of the total reactive power target value of the wind turbine group to the total inductive reactive power limit of the wind turbine group.

[0070] Furthermore, the reactive power control method for a wind turbine group according to an exemplary embodiment of this disclosure may further include: controlling the reactive power of each wind turbine generator set according to a determined reactive power target value for each wind turbine generator set. For example, a reactive power command with a command value corresponding to its reactive power target value may be sent to each wind turbine generator set, so that each wind turbine generator set responds to the received reactive power command and controls its reactive power output.

[0071] According to an exemplary embodiment of this disclosure, a reactive power closed-loop control method combining PI and reactive power command feedforward is proposed. This method can improve control accuracy and minimize reactive power response fluctuations caused by mismatches between unit reactive power output and command values. By reasonably calculating and setting the PI saturation limit value, this method prevents oversaturation of the reactive power command caused by unit response problems, thus avoiding large fluctuations in reactive power. This allows the overall control to meet normal control requirements while minimizing control fluctuations and negative impacts caused by integral control, enhancing the stability and reliability of the overall control. This method has significant practical value in the field.

[0072] Figure 4 A flowchart illustrating a reactive power control method for a wind turbine group according to another exemplary embodiment of the present disclosure is provided. As an example, the reactive power control method for a wind turbine group according to another exemplary embodiment of the present disclosure can be executed by a wind turbine group controller, for example, the wind turbine group controller can be a wind farm controller.

[0073] Reference Figure 4 and combined Figure 3 In step S201, the wind turbine data of the wind turbine generator sets in the wind turbine group are traversed through communication to obtain information such as single-unit reactive power command, actual reactive power output, upper limit of reactive power output, and lower limit of reactive power output.

[0074] In step S202, the total reactive power Q of the wind turbine group is calculated based on the reactive power output of a single unit, the upper limit of reactive power output, and the lower limit of reactive power output. meas The total power capacity of the wind turbine group has no upper limit Q. TMAXWF (Control the upper limit of reactive power command for the wind turbine group Q) max Generally, the upper limit of the actual no-function capacity of the turbine group and the lower limit of the total no-function capacity of the wind turbine group are taken as Q. TMINWF(Control the lower limit of reactive power command for the wind turbine group Q) min Generally, the lower limit of the actual non-functional capacity of the machine group is taken.

[0075] In step S203, the wind turbine group controller receives the reactive power command Q from the power station AVC system. set And according to Q max and Q min The value is limited; the reactive power command deviation value is calculated based on the reactive power command of the wind turbine group and the actual reactive power output of the group.

[0076] In step S204, it is determined whether the reactive power command deviation value exceeds the control dead zone. If it exceeds the control dead zone, step S205 is executed; otherwise, the process returns to step S201. Wherein, D... bnQ D represents the dead zone under reactive power control. bpQ This indicates the dead zone in reactive power control.

[0077] In step S205, the upper limit value Q of the PI saturation limit is calculated and set. TMAXOFFSET and lower limit value Q TMINOFFSET .

[0078] In step S206, the total reactive power command is fed forward directly controlled, and based on the reactive power command deviation value Q... error Perform closed-loop PI control of the generator group's reactive power to update the total reactive power command of the generator group.

[0079] In step S207, the reactive power instructions for each generator set are updated based on the total reactive power instructions of the generator set according to a specific allocation algorithm. It should be noted that this disclosure does not restrict the reactive power allocation strategy for the generator set; therefore, different reactive power allocation strategies are applicable to this disclosure.

[0080] After step S207, the next reactive power control cycle begins, and steps S201 to S207 are repeated.

[0081] It should be noted that the above process is only an introduction to the overall control. The order of some steps can be adjusted accordingly, but it will not affect the final control effect of the method.

[0082] The exemplary embodiments of this disclosure employ a reactive power closed-loop control method combining PI control and reactive power command feedforward. This method can improve reactive power control accuracy while minimizing reactive power response fluctuations caused by mismatches between generator reactive power output and commands. Specifically, because generator reactive power output is limited by its own constraints (such as terminal voltage), after receiving a reactive power command, the actual reactive power output may consistently deviate from the target command during execution. This deviation differs from the generator's reactive power response accuracy and is influenced by other constraints. In this situation, if the reactive power closed-loop control is based solely on deviation control or PI-based closed-loop control, the commands from the generator group will continuously accumulate due to the superposition of closed-loop factors until the upper or lower limit of the generator group's reactive power capacity is reached. Thus, after the generator constraints return to normal, the generator group will quickly respond to the reactive power command, causing the actual reactive power output to rapidly reach the upper or lower limit of the generator group's capacity. This leads to significant fluctuations in the generator group's reactive power output, resulting in a large deviation from the command and affecting the overall control effect. In more severe cases, it may cause voltage fluctuations or even oscillations at the power station. That is, when the generator group is subject to other safety constraints, such as excessively high or low voltage or other factors that prevent the units from continuing to follow the reactive power command, the PI control output value will continuously increase until it reaches the saturation upper limit value Q. TMQX Or the lower limit of saturation Q TMIN As can be seen from the overall control strategy, in order to flexibly adjust the reactive power output of the generator group between the upper and lower limits, Q... TMQX It needs to be set to the maximum value of the cluster's non-functional capabilities, Q. TMIN The reactive power capacity of the wind turbine group needs to be set as a lower limit, with both the upper and lower limits being relatively large. If changes in unit or system conditions allow the wind turbine group to respond to reactive power commands, significant reactive power control fluctuations will occur, hindering closed-loop reactive power control and system voltage stability. In more severe cases, this could cause oscillations in the overall control of the wind farm. To address the oversaturation problem of PI control, this disclosure considers the characteristics of wind turbine group reactive power control and adopts a feedforward control method. Reactive power commands are directly distributed to the wind turbine group, and the deviation between the reactive power command and the actual reactive power generated by each unit is the control deviation. Then, PI closed-loop control is applied to the overall control deviation. This significantly reduces the saturation limit of PI closed-loop control and avoids the resulting reactive power fluctuations.

[0083] Figure 5 A structural block diagram of a reactive power control device for a wind turbine group according to an exemplary embodiment of the present disclosure is shown.

[0084] like Figure 5As shown, the reactive power control device for a wind turbine group according to an exemplary embodiment of the present disclosure includes: a data acquisition unit 101, a feedforward control unit 102, a closed-loop control unit 103, a total target value determination unit 104, and a single-unit target value determination unit 105.

[0085] Specifically, the data acquisition unit 101 is configured to acquire the total reactive power demand value that the power grid needs to achieve for the wind turbine group and the actual total reactive power value of the wind turbine group.

[0086] The feedforward control unit 102 is configured to input the total reactive power demand value into the feedforward controller to obtain the first reactive power target value output by the feedforward controller.

[0087] The closed-loop control unit 103 is configured to input the difference between the total reactive power demand value and the actual total reactive power value into the PI controller to obtain the second reactive power target value output by the PI controller.

[0088] The total target value determination unit 104 is configured to determine the total reactive power target value of the wind turbine group based on the first reactive power target value and the second reactive power target value.

[0089] The single-unit target value determination unit 105 is configured to determine the reactive power target value of each wind turbine generator unit in the wind turbine group based on the total reactive power target value.

[0090] As an example, the PI controller may be an anti-integral saturation PI controller, wherein the reactive power control device for a wind turbine group according to an exemplary embodiment of the present disclosure may further include: a saturation limit setting unit (not shown), which is configured to set an upper limit value and a lower limit value of the saturation limit of the anti-integral saturation module of the PI controller based on the feedforward coefficient of the feedforward controller.

[0091] As an example, the saturation limit setting unit can be configured to: when the feedforward coefficient is 1, set the upper limit of the saturation limit to the sum of the reactive power control accuracy of each wind turbine generator set, and set the lower limit of the saturation limit to the negative of the sum of the reactive power control accuracy of each wind turbine generator set.

[0092] As an example, the saturation limit setting unit can be configured to: when the feedforward coefficient is not 1, set the upper limit of the saturation limit based on the sum of the reactive power control accuracy of each wind turbine generator set, the total capacitive reactive power limit of the wind turbine group, and the feedforward coefficient; and set the lower limit of the saturation limit based on the negative number of the sum of the reactive power control accuracy of each wind turbine generator set, the total inductive reactive power limit of the wind turbine group, and the feedforward coefficient.

[0093] As an example, the total target value determination unit 104 can be configured to: perform a limiting process on the sum of the first reactive power target value and the second reactive power target value, and use the result of the limiting process as the total reactive power target value of the wind turbine group, wherein the upper limit of the limiting process is the total capacitive reactive power limit of the wind turbine group, and the lower limit of the limiting process is the total inductive reactive power limit of the wind turbine group.

[0094] As an example, the single-unit target value determination unit 105 can be configured to: when the total reactive power target value is greater than 0, for each of the wind turbine generator sets, determine the reactive power target value of that wind turbine generator set by multiplying the capacitive reactive power limit of that wind turbine generator set by a first proportional coefficient; when the total reactive power target value is less than 0, for each of the wind turbine generator sets, determine the reactive power target value of that wind turbine generator set by multiplying the inductive reactive power limit of that wind turbine generator set by a second proportional coefficient; wherein, the first proportional coefficient is the ratio of the total reactive power target value to the total capacitive reactive power limit of the wind turbine group; and the second proportional coefficient is the ratio of the total reactive power target value to the total inductive reactive power limit of the wind turbine group.

[0095] As an example, the data acquisition unit 101 can be configured to: acquire the actual reactive power value, capacitive reactive power limit value, and inductive reactive power limit value of each wind turbine generator set; determine the total actual reactive power value of the wind turbine group as: the sum of the actual reactive power values ​​of each wind turbine generator set; determine the total capacitive reactive power limit value of the wind turbine group as: the sum of the capacitive reactive power limit values ​​of each wind turbine generator set; and determine the total inductive reactive power limit value of the wind turbine group as: the sum of the inductive reactive power limit values ​​of each wind turbine generator set.

[0096] As an example, a reactive power control device according to an exemplary embodiment of this disclosure may be installed in a wind turbine group controller, which is electrically connected to the main controller of each wind turbine generator in the wind turbine group and a wind farm controller. For example, the wind farm controller is used to send a total reactive power demand value.

[0097] As an example, a reactive power control device according to an exemplary embodiment of the present disclosure may be installed in a wind farm controller, wherein the main controller of each wind turbine generator set of the wind turbine group is electrically connected to the wind farm controller.

[0098] It should be understood that the specific processing performed by the reactive power control device according to the exemplary embodiments of this disclosure has been referenced. Figures 1 to 4 A detailed description has been provided, and the relevant details will not be repeated here.

[0099] It should be understood that the various units in the reactive power control device according to the exemplary embodiments of this disclosure may be implemented as hardware components and / or software components. Those skilled in the art can implement the various units, for example, using field-programmable gate arrays (FPGAs) or application-specific integrated circuits (ASICs), based on the processes performed by the defined various units.

[0100] Figure 6 A structural block diagram of a wind turbine group controller according to an exemplary embodiment of the present disclosure is shown.

[0101] like Figure 6 As shown, the wind turbine group controller according to the exemplary embodiments of the present disclosure, in addition to including the reactive power control device for the wind turbine group according to the exemplary embodiments of the present disclosure, may also include: a data acquisition module, a data interaction module, a front-end human-machine interaction control platform, a data management platform, a comprehensive alarm module, and an operation analysis and evaluation module.

[0102] Specifically, the data acquisition module mainly completes the acquisition of electrical analog quantity information of wind turbine units in the wind farm, which may include, but is not limited to, phase voltage, phase current, line voltage, active power, reactive power, apparent power, etc. of each phase of the unit.

[0103] The data interaction module mainly realizes the communication function between the system and upstream and downstream devices. The data information includes telemetry, teleindication, etc. The communication protocol may include, but is not limited to: Modbus, IEC60870-5-101 / 104, OPC UA, etc.

[0104] The front-end human-machine interaction control platform is mainly a front-end server, which can be a PC or other forms of devices with human-machine interaction interfaces. Its main function is to provide personnel with methods and means to monitor, view, operate, control, draw views, real-time curves, and reports on the control system.

[0105] The data management platform is mainly a historical database used to save parameter settings, lockout settings, and adjustment processes.

[0106] The integrated alarm module mainly provides fault diagnosis functions for the device itself, such as communication abnormalities, program crashes, and protection triggers. When an abnormality occurs, the device can sound an alarm and stop automatic adjustment. When the abnormality is resolved, the program can return to normal.

[0107] The operation analysis and evaluation module can perform online assessment of equipment operation, online analysis and calculation of control effects, and evaluation of the overall system control effect, such as optimizing control time, control cycle, strategy generation time, and control pass rate.

[0108] The reactive power control device of the wind turbine group mainly completes the calculation of the overall reactive power control strategy and the generation of instructions.

[0109] An exemplary embodiment of this disclosure provides a computer-readable storage medium storing a computer program that, when executed by a processor, causes the processor to perform a reactive power control method for a wind turbine group as described in the exemplary embodiment above. The computer-readable storage medium is any data storage device capable of storing data read from a computer system. Examples of computer-readable storage media include: read-only memory, random access memory, read-only optical disk, magnetic tape, floppy disk, optical data storage device, and carrier waves (such as data transmission via the Internet through wired or wireless transmission paths).

[0110] A reactive power control device for a wind turbine group according to an exemplary embodiment of the present disclosure includes a processor (not shown) and a memory (not shown), wherein the memory stores a computer program that, when executed by the processor, causes the processor to perform a reactive power control method for a wind turbine group as described in the exemplary embodiment above.

[0111] As an example, the reactive power control device can be installed in the wind turbine group controller, which is electrically connected to the main controller of each wind turbine generator in the wind turbine group and the wind farm controller. For example, the wind farm controller is used to send the total reactive power demand value.

[0112] As an example, the reactive power control device can be installed in the wind farm controller, and the main controller of each wind turbine generator set in the wind turbine group is electrically connected to the wind farm controller.

[0113] While some exemplary embodiments of this disclosure have been shown and described, those skilled in the art will understand that modifications may be made to these embodiments without departing from the principles and spirit of this disclosure, which are defined by the claims and their equivalents.

Claims

1. A method for reactive power control of a wind turbine group, characterized in that, include: Obtain the total reactive power demand value that the power grid needs to achieve for the wind turbine group and the actual total reactive power value of the wind turbine group; The total reactive power demand value is input into the feedforward controller to obtain the first reactive power target value output by the feedforward controller; The difference between the total reactive power demand value and the actual total reactive power value is input into the PI controller to obtain the second reactive power target value output by the PI controller; Based on the first and second reactive power target values, the total reactive power target value of the wind turbine group is determined. Based on the total reactive power target value, the reactive power target value for each wind turbine generator unit in the wind turbine group is determined. The step of determining the total reactive power target value of the wind turbine group based on the first reactive power target value and the second reactive power target value includes: The sum of the first reactive power target value and the second reactive power target value is subjected to a limiting process, and the result of the limiting process is used as the total reactive power target value of the wind turbine group. Wherein, the upper limit of the limiting process is the total capacitive reactive power limit of the wind turbine group, and the lower limit of the limiting process is the total inductive reactive power limit of the wind turbine group.

2. The reactive power control method according to claim 1, characterized in that, The PI controller is a PI controller that prevents integral saturation. The reactive power control method further includes: setting the upper limit and lower limit of the saturation limit of the anti-integral saturation module of the PI controller based on the feedforward coefficient of the feedforward controller.

3. The reactive power control method according to claim 2, characterized in that, The steps for setting the upper and lower limits of the saturation limit of the anti-integral saturation module of the PI controller based on the feedforward coefficient of the feedforward controller include: When the feedforward coefficient is 1, the upper limit of the saturation limit is set to the sum of the reactive power control accuracies of all wind turbine generators, and the lower limit of the saturation limit is set to the negative of the sum of the reactive power control accuracies of all wind turbine generators; and / or, When the feedforward coefficient is not 1, the upper limit of the saturation limit is set based on the sum of the reactive power control accuracy of each wind turbine generator set, the total capacitive reactive power limit of the wind turbine group, and the feedforward coefficient; and the lower limit of the saturation limit is set based on the negative number of the sum of the reactive power control accuracy of each wind turbine generator set, the total inductive reactive power limit of the wind turbine group, and the feedforward coefficient.

4. The reactive power control method according to claim 1, characterized in that, Based on the total reactive power target value, the steps for determining the reactive power target value of each wind turbine generator unit in the wind turbine group include: When the total reactive power target value is greater than 0, for each of the wind turbine generator sets, the product of the capacitive reactive power limit of the wind turbine generator set and the first proportional coefficient is determined as the reactive power target value of the wind turbine generator set. When the total reactive power target value is less than 0, for each wind turbine generator set, the product of the inductive reactive power limit of the wind turbine generator set and the second proportional coefficient is determined as the reactive power target value of the wind turbine generator set. Wherein, the first proportionality coefficient is the ratio of the total reactive power target value to the total capacitive reactive power limit value of the wind turbine group; the second proportionality coefficient is the ratio of the total reactive power target value to the total inductive reactive power limit value of the wind turbine group.

5. The reactive power control method according to any one of claims 1 to 4, characterized in that, The reactive power control method also includes: Obtain the actual reactive power value, capacitive reactive power limit, and inductive reactive power limit of each wind turbine generator set; The total reactive power of the wind turbine group is defined as the sum of the actual reactive power of each wind turbine generator set. The total capacitive non-functional capacity limit of the wind turbine group is defined as the sum of the capacitive non-functional capacity limits of each wind turbine generator set. The total inductive non-functional capacity limit of the wind turbine group is defined as the sum of the inductive non-functional capacity limits of each wind turbine generator unit.

6. A reactive power control device for a wind turbine group, characterized in that, include: The data acquisition unit is configured to acquire the total reactive power demand value that the power grid needs to achieve from the wind turbine group and the actual total reactive power value of the wind turbine group; The feedforward control unit is configured to input the total reactive power demand value into the feedforward controller to obtain a first reactive power target value output by the feedforward controller. A closed-loop control unit is configured to input the difference between the total reactive power demand value and the actual total reactive power value into a PI controller to obtain a second reactive power target value output by the PI controller. The total target value determination unit is configured to determine the total reactive power target value of the wind turbine group based on the first reactive power target value and the second reactive power target value; The single-unit target value determination unit is configured to determine the reactive power target value of each wind turbine generator unit in the wind turbine group based on the total reactive power target value. The total target value determination unit is configured to: perform amplitude limiting processing on the sum of the first reactive power target value and the second reactive power target value, and use the result of the amplitude limiting processing as the total reactive power target value of the wind turbine group, wherein the upper limit of the amplitude limiting processing is the total capacitive reactive power limit of the wind turbine group, and the lower limit of the amplitude limiting processing is the total inductive reactive power limit of the wind turbine group.

7. The reactive power control device according to claim 6, characterized in that, The reactive power control device is installed in the wind turbine group controller, which is electrically connected to the main controller of each wind turbine generator set in the wind turbine group and the wind farm controller; the wind farm controller is used to send the total reactive power demand value. or, The reactive power control device is installed in the wind farm controller, and the main controller of each wind turbine generator set in the wind turbine group is electrically connected to the wind farm controller.

8. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it causes the processor to perform the reactive power control method for the wind turbine group as described in any one of claims 1 to 5.

9. A reactive power control device for a wind turbine group, characterized in that, The reactive power control device includes: processor; A memory storing a computer program that, when executed by a processor, causes the processor to perform the reactive power control method for a wind turbine group as described in any one of claims 1 to 5.

10. The reactive power control device according to claim 9, characterized in that, The reactive power control device is installed in the wind turbine group controller, which is electrically connected to the main controller of each wind turbine generator set in the wind turbine group and the wind farm controller; the wind farm controller is used to send the total reactive power demand value. or, The reactive power control device is installed in the wind farm controller, and the main controller of each wind turbine generator set in the wind turbine group is electrically connected to the wind farm controller.

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