Wind power plant reactive power control method, device, system, equipment and program product

Abstract

The invention provides a wind power plant reactive power control method, device, system, equipment and program product, the method is at least used for realizing closed-loop control of wind power plant grid-connected point reactive power and voltage, and the method comprises the following steps: obtaining a grid-connected point reactive power target value, a reactive power feedback value and a grid-connected point voltage feedback value; based on the grid-connected point reactive power target value, the reactive power feedback value and the grid-connected point voltage feedback value, adopting double-loop PI control to obtain a fan group reactive power distribution value so as to maintain the stability of the grid-connected point reactive power and voltage; performing equal proportion distribution according to the fan group reactive power distribution value and the available reactive power of each fan to obtain a reactive power target value of each fan; and sending the reactive power target value to each wind turbine generator to enable the wind turbine generator to respond to the corresponding reactive power target value. According to the invention, through double-loop reactive voltage closed-loop control, stable operation of reactive power and voltage of a grid-connected point of the wind power plant is maintained, and through reasonable distribution of reactive power, it is ensured that the voltage of a fan side does not exceed the limit.

Description

Technical Field

[0001] The present disclosure relates to the field of new energy technology, and in particular to a method, device, system, equipment and program product for controlling reactive power of a wind farm. Background Art

[0002] After large-scale wind power is connected to the grid, the volatility and randomness of wind resources can easily cause fluctuations in active / reactive power of wind farms, which will seriously impact the frequency and voltage of the power grid. Therefore, it is very important to build a "grid-friendly" wind farm. "Grid-friendly" wind farms require wind turbines to have active, reactive, frequency modulation, inertia and voltage regulation functions, and be able to ensure the stable operation of the power grid when the power grid fluctuates. Among them, for reactive power control of wind farms, the current mainstream technology is that the wind turbine energy management platform controls the reactive power of wind turbines through average, geometric and other distribution methods according to the reactive power instructions issued by the AVC (automatic voltage control) substation of the wind farm, and the wind turbine converter responds. However, this method of allocating reactive power in place at one time will cause uneven voltage on the wind turbine side. When the reactive power instruction is large, it will cause voltage fluctuations on the wind turbine side. If the voltage on the wind turbine side is too high or too low, it will cause high and low wear failures of the wind turbine, which will affect the stability of the voltage at the grid connection point.

[0003] In addition, in the prior art, the reactive power control parameters of a single machine are optimized by adaptively adjusting the voltage of the wind turbine, and the average reactive power setting value of the single machine after PI (Proportional-Integral) control is superimposed to realize the distribution of reactive power. The reactive power distribution is averaged, which is not suitable for mixed wind farms. Moreover, the redistribution through the optimization parameters of a single machine is likely to cause reactive power oscillation in the whole farm, thereby causing voltage fluctuations. Summary of the invention

[0004] The technical problem to be solved by the present disclosure is to overcome the defect in the prior art that unreasonable reactive power distribution of wind turbine groups causes excessively high or low voltage on the wind turbine side, which can lead to high or low breakdown of the wind turbine, and to provide a wind farm reactive power control method, device, system, equipment and program product.

[0005] The present invention solves the above technical problems through the following technical solutions:

[0006] In a first aspect, the present disclosure provides a wind farm reactive power control method, wherein the wind farm reactive power control method is at least used to implement voltage closed-loop control, including:

[0007] Obtaining the grid connection point voltage target value, reactive power feedback value and grid connection point voltage feedback value;

[0008] Based on the grid connection point voltage target value, the reactive power feedback value and the grid connection point voltage feedback value, as well as the upper and lower limits of the grid connection point voltage, a double-loop PI control is adopted to obtain a reactive power distribution value of the wind turbine group;

[0009] The reactive power target value of each controllable wind turbine is obtained by performing proportional distribution according to the reactive power distribution value of the wind turbine group and the reactive power output capacity of each wind turbine;

[0010] The reactive power target value of the controllable wind turbine is sent to each wind turbine group, so that the wind turbine group responds to the corresponding reactive power target value.

[0011] Optionally, obtaining a target grid connection point voltage value includes:

[0012] Obtaining the reactive power target value and reactive power feedback value of the grid connection point;

[0013] Based on the reactive power target value of the grid connection point and the reactive power feedback value of the grid connection point, outer loop PI control is adopted to obtain the grid connection point voltage target value.

[0014] Optionally, the outer loop PI control is adopted to obtain the grid connection point voltage target value based on the grid connection point reactive power target value and the grid connection point reactive power feedback value, including:

[0015] Obtaining a first difference between the reactive power target value of the grid connection point and the reactive power feedback value of the grid connection point;

[0016] The first difference is added to a preset feedforward value after being controlled by the outer loop PI to obtain the grid connection point voltage target value.

[0017] Optionally, the inner loop PI control is adopted to obtain the reactive power distribution value of the wind turbine group based on the grid connection point voltage target value, the grid connection point voltage feedback value and the grid connection point reactive power feedback value, as well as the upper and lower limits of the grid connection point voltage, including:

[0018] Obtaining the upper and lower limits of the grid connection point voltage;

[0019] Based on the upper and lower limits of the grid connection point voltage, the grid connection point voltage target value is limited, and the voltage target value after limiting is used as the grid connection point voltage reference value;

[0020] Obtaining a second difference between the grid connection point voltage reference value and the grid connection point voltage feedback value;

[0021] Performing inner loop PI control on the second difference to obtain a reactive power reference value of the wind turbine group;

[0022] Obtaining upper and lower limits of the reactive power reference value of the wind turbine group, and limiting the reactive power reference value of the wind turbine group;

[0023] The reactive power distribution value of the wind turbine group is obtained according to the difference between the reactive power reference value of the wind turbine group and the reactive power feedback value of the uncontrollable wind turbine.

[0024] Optionally, before the step of performing reactive proportional distribution according to the reactive power distribution value of the wind turbine group to obtain the reactive power target value of each controllable wind turbine, the wind farm reactive power control method further includes:

[0025] Obtain the fan side voltage value, the fan side voltage safety upper limit, the fan side voltage safety lower limit, the fan reactive power feedback value, the fan available inductive reactive power and available capacitive reactive power;

[0026] Based on the wind turbine side voltage value, the wind turbine side voltage safety upper limit, the wind turbine side voltage safety lower limit, the wind turbine reactive power feedback value, the available inductive reactive power and the available capacitive reactive power, the available inductive reactive power and the available capacitive reactive power are optimized to obtain the optimized wind turbine available inductive reactive power and the wind turbine available capacitive reactive power;

[0027] The reactive power target value of each controllable wind turbine is obtained by performing reactive proportional distribution according to the reactive power distribution value of the wind turbine group, including:

[0028] According to the optimized available inductive reactive power of the wind turbine and the available capacitive reactive power of the wind turbine, the reactive power distribution value of the wind turbine group is distributed equally among the controllable wind turbines to obtain the reactive power target value of the controllable wind turbine.

[0029] Optionally, the optimizing the available inductive reactive power and the available capacitive reactive power to obtain the optimized available inductive reactive power and the available capacitive reactive power of the wind turbine includes:

[0030] Filtering the fan side voltage value within a preset time period to obtain a filtered voltage;

[0031] Obtaining the current boostable voltage on the fan side based on the difference between the fan side voltage safety upper limit and the filter voltage;

[0032] According to the relationship function between the reactive power and the voltage on the wind turbine side and the current increaseable voltage on the wind turbine side, the current increaseable inductive reactive power value is obtained;

[0033] The sum of the wind turbine reactive power feedback value and the current inductive reactive power value that can be increased is obtained to obtain the updated wind turbine side voltage safety upper limit, which is used as the wind turbine side voltage safety upper limit. The total inductive reactive power that can be generated by the internal fans;

[0034] The sum is passed through zero and the available inductive reactive power is limited to obtain the optimized available inductive reactive power of the wind turbine.

[0035] Optionally, the optimizing the available inductive reactive power and the available capacitive reactive power to obtain the optimized available inductive reactive power and the available capacitive reactive power of the wind turbine further includes:

[0036] Obtaining a difference between the wind turbine side voltage safety lower limit and the filter voltage, and using the difference as the current wind turbine side drop-able voltage;

[0037] According to the relationship function and the current machine-side voltage that can be reduced, a current value of capacitive reactive power that can be increased is obtained;

[0038] Based on the sum of the wind turbine reactive power feedback value and the current capacitive reactive power value that can be increased, an updated wind turbine side voltage safety lower limit is obtained to be used as the wind turbine side voltage safety lower limit The total capacitive reactive power that can be generated by the internal fans;

[0039] The sum is passed through zero and the available capacitive reactive power is limited.

[0040] In a second aspect, the present disclosure provides a wind farm reactive power control device, the wind farm reactive power control device is used to implement reactive power control, and includes: a voltage closed-loop control module;

[0041] The voltage closed-loop control module includes an inner-loop PI controller, which is used to limit the target voltage value of the grid connection point in the inner loop, and distribute the reactive power of the wind turbine according to the voltage target value after limiting;

[0042] The voltage closed-loop control module is connected to the grid connection point voltage target value, the grid connection point voltage feedback value and the grid connection point voltage upper and lower limits, and outputs the wind turbine group reactive power distribution value based on the grid connection point voltage target value, the grid connection point voltage feedback value and the grid connection point voltage upper and lower limits.

[0043] Optionally, the wind farm reactive power control device further comprises: a reactive power closed-loop control module;

[0044] The reactive power closed-loop control module includes an outer-loop PI controller, which is used to obtain the voltage target value based on the reactive power target value of the grid connection point and the reactive power feedback value of the entire field.

[0045] Optionally, the voltage closed-loop control module further includes: a first limiter, a second limiter, a first adder, and a second adder;

[0046] The input end of the first limiter is connected to the grid connection point voltage target value, the control end of the first limiter is respectively connected to the preset grid connection point voltage upper limit and voltage lower limit, the output end of the first limiter outputs the grid connection point voltage reference value to the first input end of the first adder, the second input end of the first adder is connected to the inverted grid connection point voltage feedback value, and the output end of the first adder outputs the second difference to the input end of the inner loop PI controller;

[0047] The output end of the inner loop PI controller outputs the reactive power reference value of the wind turbine group to the input end of the second limiter, the control end of the second limiter is respectively connected to the upper limit of the reactive power of the wind turbine group and the lower limit of the reactive power of the wind turbine group, the output end of the second limiter is connected to the first input end of the second adder, and the second input end of the second adder is connected to the reactive power feedback value of the inverted uncontrollable wind turbine;

[0048] The output end of the second adder outputs the reactive power distribution value of the wind turbine group.

[0049] Optionally, the reactive power closed-loop control module further includes: a third adder and a fourth adder;

[0050] The first input end of the third adder is connected to the grid-connected point reactive power target value, the second input end of the third adder is connected to the inverted grid-connected point reactive power feedback value, and the output end of the third adder outputs the first difference to the input end of the outer loop PI controller;

[0051] The output end of the outer loop PI controller is connected to the first input end of the fourth adder, the second input end of the fourth adder is connected to the feedforward value, and the output end of the fourth adder outputs the grid connection point voltage target value.

[0052] In a third aspect, the present disclosure provides a wind farm reactive power control system, which is used at least to achieve closed-loop control of reactive power and voltage at a wind farm grid connection point, including: an acquisition module, a reactive power closed-loop control module, a reactive proportional distribution module, and a transmission module;

[0053] The acquisition module is used to obtain the grid connection point voltage target value, the grid connection point voltage feedback value and the reactive power feedback value;

[0054] The reactive power closed-loop control module is used to adopt double-loop PI control and obtain the reactive power distribution value of the wind turbine group based on the grid connection point voltage target value, the grid connection point voltage feedback value, the grid connection point reactive power feedback value, and the grid connection point voltage upper and lower limits, so as to maintain the stability of the grid connection point voltage;

[0055] The reactive power proportional distribution module is used to perform proportional distribution according to the reactive power distribution value of the wind turbine group and the reactive power output capacity of each wind turbine to obtain the reactive power target value of each controllable wind turbine;

[0056] The sending module is used to send the reactive power target value of the controllable wind turbine to each wind turbine group, so that the wind turbine group responds to the corresponding reactive power target value.

[0057] Optionally, the acquisition module is further used to acquire a reactive power target value of a grid connection point and a reactive power feedback value of a grid connection point;

[0058] The acquisition module is also used to adopt outer loop PI control and obtain the grid connection point voltage target value based on the grid connection point reactive power target value and the grid connection point reactive power feedback value.

[0059] Optionally, the reactive power closed-loop control module is further used to obtain a first difference between the reactive power target value of the grid connection point and the reactive power feedback value of the grid connection point;

[0060] The reactive power closed-loop control module is further used to add the first difference after the outer loop PI control to a preset feedforward value to obtain the grid connection point voltage target value;

[0061] Optionally, the reactive power closed-loop control module is also used to obtain the upper and lower limits of the grid connection point voltage for safe operation of the grid connection point;

[0062] The reactive power closed-loop control module is also used to limit the grid connection point voltage target value based on the grid connection point voltage upper and lower limits, and use the grid connection point voltage target value after limiting as the grid connection point voltage reference value;

[0063] The reactive power closed-loop control module is also used to obtain a second difference between the grid connection point voltage reference value and the grid connection point voltage feedback value;

[0064] The reactive power closed-loop control module is further used to perform the inner-loop PI control on the second difference to obtain a reactive power target value of the wind turbine group;

[0065] The reactive power closed-loop control module is also used to obtain the upper and lower limits of the reactive power reference value of the wind turbine group and to limit the reactive power target value of the wind turbine group;

[0066] The reactive power closed-loop control module is further used to obtain the reactive power distribution value of the wind turbine group according to the difference between the reactive power target value of the wind turbine group and the reactive power feedback value of the uncontrollable wind turbine.

[0067] Optionally, the wind farm reactive power control system further comprises: a reactive power optimization module;

[0068] The acquisition module is also used to acquire the wind turbine side voltage value, the wind turbine side voltage safety upper limit, the wind turbine side voltage safety lower limit, the wind turbine reactive power feedback value, the wind turbine available inductive reactive power and available capacitive reactive power;

[0069] The reactive power optimization module is used to optimize the available inductive reactive power and the available capacitive reactive power based on the wind turbine side voltage value, the wind turbine side voltage safety upper limit, the wind turbine side voltage safety lower limit, the wind turbine reactive power feedback value, the available inductive reactive power and the available capacitive reactive power, and obtain the optimized wind turbine available inductive reactive power and wind turbine available capacitive reactive power;

[0070] The reactive proportional distribution module is also used to distribute the reactive power distribution value of the wind turbine group in equal proportion among the controllable wind turbines according to the available inductive reactive power of the wind turbine and the available capacitive reactive power of the wind turbine to obtain the reactive power target value of the controllable wind turbine; wherein, the available inductive reactive power of the wind turbine represents the available inductive reactive power of a single wind turbine when the reactive power distribution value of the wind turbine group is positive, and the available capacitive reactive power of the wind turbine represents the available capacitive reactive power of a single wind turbine when the reactive power distribution value of the wind turbine group is negative.

[0071] Optionally, the reactive power optimization module is further used to filter the voltage value on the fan side within a preset time period to obtain a filtered voltage;

[0072] The reactive power optimization module is further used to obtain the current boostable voltage on the wind turbine side based on the difference between the wind turbine side voltage safety upper limit and the filter voltage;

[0073] The reactive power optimization module is also used to obtain the current increaseable inductive reactive power value according to the relationship function between the reactive power and the voltage on the wind turbine side and the current increaseable voltage on the wind turbine side;

[0074] The reactive power optimization module is also used to obtain the sum of the reactive power feedback value of the wind turbine and the current inductive reactive power value that can be increased;

[0075] The reactive power optimization module is further used to obtain the optimized available inductive reactive power of the wind turbine by limiting the sum through zero and the available inductive reactive power.

[0076] Optionally, the reactive power optimization module is further used to obtain the difference between the wind turbine side voltage safety lower limit and the filter voltage, and use the difference as the current wind turbine side drop-able voltage;

[0077] The reactive capacity optimization module is further used for reducing the voltage on the machine side according to the relationship function and the current voltage reduction;

[0078] The reactive power optimization module is further used to obtain the current increaseable capacitive reactive power value according to the relationship function and the current machine-side dropable voltage;

[0079] The reactive power optimization module is also used to obtain the sum of the reactive power feedback value of the wind turbine and the current increaseable capacitive reactive power value;

[0080] The reactive power optimization module is further used for limiting the sum through zero and the available capacitive reactive power to obtain the optimized available capacitive reactive power of the wind turbine.

[0081] In a fourth aspect, the present disclosure further provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and used to run on the processor, wherein the processor implements the above-mentioned wind farm reactive power control method when executing the computer program.

[0082] In a fifth aspect, the present disclosure further provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program implements the above-mentioned wind farm reactive power control method when executed by a processor.

[0083] In a sixth aspect, the present disclosure further provides a computer program product, including a computer program, which implements the wind farm reactive power control method as described above when executed by a processor.

[0084] On the basis of being in accordance with the common sense in the art, the above-mentioned preferred conditions can be arbitrarily combined to obtain the preferred embodiments of the present disclosure.

[0085] The positive progressive effect of the present disclosure is that in reactive power control, voltage closed-loop control is achieved through inner-loop PI control, which can ensure that the voltage on the wind turbine side does not exceed the limit under the condition of a clear voltage target value, so as to maintain the stable operation of the whole-field voltage and take into account the impact of the wind turbine reactive output on the whole-field voltage.

[0086] Furthermore, outer-loop PI control is used for reactive power control, and the inner-loop PI control and outer-loop PI control constitute cascade reactive PI control. The inner loop of the voltage closed-loop control is embedded in the reactive power closed-loop control, and the reactive output of the wind turbine is reasonably allocated under the constraints of the upper and lower limits of the grid-connected point voltage and the upper and lower limits of the reactive power, so as to maintain the stable operation of the voltage in the entire field.

[0087] In addition, considering the voltage-reactive function of the specific model and the current reactive operating condition of the wind turbine, the current wind turbine side voltage and actual reactive output are combined to calculate the additional inductive reactive power value and the additional capacitive reactive power value of the wind turbine under the current operating conditions, and then optimize the inductive reactive power and capacitive reactive power of the wind turbine, eliminating the excessive correction of the inductive / capacitive reactive power of the wind turbine when the actual reactive output is not considered, making the field-level control more stable. BRIEF DESCRIPTION OF THE DRAWINGS

[0088] Figure 1 A flowchart of a wind farm reactive power control method provided in Embodiment 1 of the present disclosure;

[0089] Figure 2A A reactive power control flow chart of a wind farm reactive power control method provided in Embodiment 1 of the present disclosure;

[0090] Figure 2B A flowchart of a specific implementation of step S11 of a wind farm reactive power control method provided in Example 1 of the present disclosure;

[0091] Figure 3 A flowchart of a specific implementation of step S12 of a wind farm reactive power control method provided in Example 1 of the present disclosure;

[0092] Figure 4 A flowchart of a specific implementation of step S123 of a wind farm reactive power control method provided in Example 1 of the present disclosure;

[0093] Figure 5 A flowchart of a specific implementation of a wind farm reactive power control method provided in Example 1 of the present disclosure;

[0094] Figure 6 A reactive power upper and lower limit optimization flow chart of a reactive power control method for a wind farm provided in Embodiment 1 of the present disclosure;

[0095] Figure 7 A flowchart of a specific implementation of step S22 of a wind farm reactive power control method provided in Example 1 of the present disclosure;

[0096] Figure 8 A flowchart of another specific implementation of step S22 of a wind farm reactive power control method provided in Embodiment 1 of the present disclosure;

[0097] Fig. 9 A comparison diagram of reactive power control curves of the entire wind farm before and after the application of an example of a reactive power control method for a wind farm provided in Embodiment 1 of the present disclosure;

[0098] Fig.10 A reactive upper and lower limits, machine-side voltage, energy management instructions and actual response change curve of wind turbine No. 1 in an example of a reactive power control method for a wind farm provided in Embodiment 1 of the present disclosure;

[0099] Fig.11 A reactive upper and lower limits, machine-side voltage, energy management instructions and actual response change curve of wind turbine No. 14, which is an example of a reactive power control method for a wind farm provided in Embodiment 1 of the present disclosure;

[0100] Fig.12 A reactive upper and lower limits, machine-side voltage, energy management instructions and actual response change curve of wind turbine No. 16, which is an example of a reactive power control method for a wind farm provided in Embodiment 1 of the present disclosure;

[0101] Fig.13A A schematic structural diagram of a wind farm reactive power control device provided in Embodiment 2 of the present disclosure;

[0102] Fig. 13B A module schematic diagram of a wind farm reactive power control system provided in Embodiment 3 of the present disclosure;

[0103] Fig.14 A schematic diagram of the structure of an electronic device provided in Embodiment 4 of the present disclosure. DETAILED DESCRIPTION

[0104] The present disclosure is further described below by way of examples, but the present disclosure is not limited to the scope of the examples.

[0105] Prefixes such as "first" and "second" are used in the embodiments of the present disclosure only to distinguish different description objects, and have no limiting effect on the position, order, priority, quantity or content of the described objects. The use of prefixes such as ordinal numbers to distinguish description objects in the embodiments of the present disclosure does not constitute a limitation on the described objects. For the statement of the described objects, please refer to the description in the context of the claims or embodiments, and no unnecessary limitation should be constituted due to the use of such prefixes. In addition, in the description of the present embodiment, unless otherwise specified, the meaning of "plurality" is two or more.

[0106] Example 1

[0107] Figure 1 A flowchart of a wind farm reactive power control method provided by an exemplary embodiment of the present disclosure, the wind farm reactive power control method is at least used to achieve reactive power and voltage closed-loop control of wind farm grid connection points, including:

[0108] S11. Obtaining the target value of the grid connection voltage U cmd , grid connection point voltage feedback value U feedback And reactive power feedback value Q Unctrl The grid voltage target value U can be obtained through the outer loop PI control cmd .

[0109] S12, based on the grid voltage target value U cmd , grid connection point voltage feedback value U feedback and the reactive power feedback value Q of the uncontrollable wind turbine Unctrl, as well as the upper and lower limits of the grid-connected point voltage, the double-loop PI control is used to obtain the wind turbine group reactive power distribution value Q dist .

[0110] S13, according to the reactive power distribution value Q of the wind turbine group dist The reactive power target value of each controllable wind turbine is obtained by proportionally allocating it to the reactive power output capacity of each wind turbine.

[0111] S14: sending the reactive power target value of the controllable wind turbine to each wind turbine group, so that the wind turbine group responds to the corresponding reactive power target value.

[0112] Among them, before implementing the wind farm reactive power control method of this embodiment, it is necessary to ensure that the communication between the wind turbine energy management platform and the AVC manufacturer in the upstream station and the downstream wind turbine master control is normal; and clarify the installed capacity of the entire wind farm, the rated voltage of the grid connection point, and the rated voltage of the machine side.

[0113] Voltage closed loop control Figure 2A In the dotted box part, the underline in the figure is used to distinguish the subscript. Through the inner loop voltage closed-loop control, when the voltage target value is clear, for example, when the field control receives the grid-connected point voltage target value, it is only necessary to close the voltage. Then, it is only necessary to execute the inner loop PI control (voltage control closed loop) to ensure that the voltage on the wind turbine side does not exceed the limit, so as to maintain the stable operation of the voltage of the entire field.

[0114] It is worth noting that in the entire control process, all data need to be normalized, the full-field values ​​involved are all one-dimensional data, and the fan-side data involved are all arrays.

[0115] In this embodiment, voltage closed-loop control is achieved through inner-loop PI control. Under the condition of clear voltage target value, it is ensured that the voltage on the wind turbine side does not exceed the upper and lower limits of the grid connection point for safe operation, that is, the voltage on the wind turbine side does not exceed the limit. Under the constraints of the upper and lower limits of the grid connection point voltage, the reactive output of the wind turbine is reasonably distributed to maintain the stable operation of the voltage in the whole field.

[0116] In one embodiment, referring to Figure 2B In step S11, "obtaining the grid voltage target value U cmd ",include:

[0117] S111. Obtaining the reactive power target value Q of the grid connection point cmd And the grid-connected point reactive power feedback value Q feedback .

[0118] S112, based on the reactive power target value Q of the grid connection point cmd And the grid-connected point reactive power feedback value Q feedback , using the outer loop PI control and obtaining the grid connection point voltage target value U cmd .

[0119] The inner and outer loop PI control can be implemented by using a PI controller. The relevant PI controller parameters can be set according to the specific application example. The settings of the proportional coefficient, integral coefficient, etc. are all existing technologies and will not be repeated here. The inner loop PI control and the outer loop PI control together constitute the cascade reactive PI control. The cascade reactive PI control process is as follows Figure 2A As shown, Figure 2A The underscore is used to distinguish the subscript. After the reactive control target of the whole field passes through the cascade reactive PI controller, the reactive target value of the whole field is proportionally distributed to each wind turbine according to the optimized upper and lower limits of the reactive power of the wind turbine. Compared with the current existing reactive control technology, this embodiment adds a voltage control link realized by the inner loop PI control, and realizes from the field control level that the reactive output of the wind turbine is controlled so that the grid connection point voltage and the machine side voltage are both operated within a safe range.

[0120] It is worth noting that in the entire control process, all data need to be normalized, the full-field values ​​involved are all one-dimensional data, and the fan-side data involved are all arrays.

[0121] This embodiment is compatible with two control modes: reactive power closed loop and voltage closed loop. If the reactive power closed loop is used, an outer loop PI controller and an inner loop PI control are used in sequence; if the voltage closed loop is used, an inner loop PI control is used. Figure 2A In order to complete the process of cascade reactive PI control when the reactive power is closed-loop, if the field control receives the voltage target value and only needs to perform closed-loop control on the voltage, it is only necessary to perform inner-loop PI control (voltage control closed-loop). The parameters of the inner and outer-loop PI controllers can be set according to specific application examples. The settings of the proportional coefficient, integral coefficient, etc. are all existing technologies and will not be repeated here.

[0122] In this embodiment, through the inner loop voltage closed-loop control, the voltage on the wind turbine side is ensured not to exceed the limit while the grid-connected point voltage target value is clearly defined, so as to maintain the stable operation of the voltage of the entire field; based on the cascade reactive PI control, the reactive power closed-loop control considering the grid-connected point voltage is realized, so that the reactive power closed-loop control includes the inner loop voltage closed-loop control, and the inner loop of the voltage closed-loop control is embedded in the reactive power closed-loop control. Taking into account the impact of the wind turbine reactive output on the entire field voltage, the cascade reactive PI control is adopted to reasonably allocate the wind turbine reactive output under the constraints of the upper and lower limits of the grid-connected point voltage and the upper and lower limits of the reactive power, so as to form an inner and outer double closed-loop to maintain the stable operation of the voltage of the entire field.

[0123] In one embodiment, referring to Figure 3 , step S112 includes:

[0124] S1121. Obtaining the reactive power target value Q of the grid connection point cmd And the reactive power feedback value Qfeedback The first difference E Q .

[0125] S1122, first difference E Q After the outer loop PI control, the voltage target value U of the grid connection point is obtained by adding the preset feedforward value. cmd .

[0126] The purpose of adding a preset feedforward in this link is to speed up the control speed, and the feedforward value is generally set to 1. The feedforward value can be set according to the actual situation.

[0127] In one embodiment, referring to Figure 4 , step S12 comprises:

[0128] S121. Obtain the upper and lower limits of the grid connection point voltage U for safe operation of the grid connection point max and U min .

[0129] S122, based on the upper and lower limits of the grid connection point voltage U max and U min , for the grid voltage target value U cmd The voltage at the grid point after limiting is set to the target value U cmd As the grid voltage reference value U ref .

[0130] S123, obtain the grid connection point voltage reference value U ref And the grid voltage feedback value U feedback The second difference E U .

[0131] S124, for the second difference E U Perform inner loop PI control to obtain the reactive power reference value Q of the wind turbine group ref .

[0132] S125. Obtain the upper and lower limits Q of the reactive power reference value of the wind turbine group max and Q min , the reactive power reference value Q of the wind turbine group ref Limiting is performed.

[0133] S126, based on the reactive power reference value Q of the wind turbine group ref and the reactive power feedback value Q of the uncontrollable wind turbine Unctrl The difference between the wind turbine group reactive power distribution value Q is obtained. dist .

[0134] In one embodiment, referring to Figure 5 Before step S13, the wind farm reactive power control method further includes:

[0135] S21. Obtain the voltage value U on the fan side WT , Wind turbine side voltage safety upper limit Wind turbine side voltage safety lower limit Wind turbine reactive power feedback value Q WT , Available inductive reactive power of the wind turbine and capacitive reactive power

[0136] S22, based on the fan side voltage value U WT , Wind turbine side voltage safety upper limit Wind turbine side voltage safety lower limit Wind turbine reactive power feedback value Q WT , Inductive reactive power and capacitive reactive power Optimize the available inductive reactive power and available capacitive reactive power of the wind turbine to obtain the optimized available inductive reactive power of the wind turbine and wind turbine available capacitive reactive power

[0137] Step S13 includes:

[0138] S131, based on the available inductive reactive power of the fan and wind turbine available capacitive reactive power The reactive power distribution value Q of the wind turbine group dist The reactive power target value of the controllable wind turbines is obtained by distributing the reactive power of the controllable wind turbines in equal proportion. Indicates the reactive power distribution value Q in the wind turbine group dist When it is positive, the available inductive reactive power of a single wind turbine and the capacitive reactive power of the wind turbine Indicates the reactive power distribution value Q in the wind turbine group dist The available capacitive reactive power of a single wind turbine when it is a negative value.

[0139] Among them, in order to consider the upper and lower limits of the powerless capacity optimization of the generator side voltage safety, Figure 6 As shown, an optimization method for available inductive reactive power and available capacitive reactive power on the wind turbine side is included.

[0140] The logic of optimizing the reactive capacity by considering the current reactive working condition of the wind turbine mainly makes up for the drawback of directly optimizing the upper and lower limits of the available inductive and available capacitive reactive power of the wind turbine according to the machine-side voltage in the prior art: if the voltage is near the critical value of the safety voltage, the reactive capacity of the wind turbine fluctuates greatly, and the reactive command of the single wind turbine will change greatly when the field control refers to the available power for allocation. Considering the response time of the wind turbine, it may cause the reactive power of the whole field to oscillate. This embodiment combines the current wind turbine side voltage and the actual reactive power output to calculate the inductive / capacitive reactive power that the wind turbine can generate under the current working condition, and then optimizes the inductive / capacitive reactive power of the wind turbine, eliminating the excessive correction of the inductive / capacitive reactive power of the wind turbine when the actual reactive power output is not considered, so that the field-level control is more stable.

[0141] The reactive power target value is sent to each controllable wind turbine. dist is a positive value, then according to the available inductive reactive power of the fan The reactive power distribution value Q of the wind turbine group dist The reactive power target value is obtained by proportional distribution; if the reactive power distribution value of the wind turbine group is Q dist If it is a negative value, then according to the available capacitive reactive power of the wind turbine The reactive power distribution value Q of the wind turbine group dist The reactive power target value of a single wind turbine is obtained by equal proportion distribution. For example, the reactive power distribution value of the wind turbine group is Q dist The available inductive reactive power of wind turbine No. 1 is 900. =1000, the available inductive reactive power of fan No. 2 is If the power is 500, then 600 is allocated to fan No. 1 and 300 is allocated to fan No. 2. It is an existing technology to proportionally allocate the reactive power distribution value of the fan group to the controllable fans according to the available inductive reactive power and the available capacitive reactive power of the fans (the upper and lower limits of the reactive power of the fans), which will not be described here.

[0142] In this embodiment, through the voltage closed-loop control of the inner loop, the voltage on the wind turbine side is ensured not to exceed the limit while the target value of the grid-connected point voltage is clearly defined, so as to maintain the stable operation of the voltage of the entire field; based on the series reactive PI control, the reactive power closed-loop control considering the grid-connected point voltage is realized, and the reactive power closed-loop control includes the voltage closed-loop control of the inner loop. The inner loop of the voltage closed-loop control is embedded in the reactive power closed-loop control. Taking into account the influence of the reactive output of the wind turbine on the voltage of the entire field, the series reactive PI control is adopted to reasonably allocate the reactive output of the wind turbine under the constraints of the upper and lower limits of the grid-connected point voltage and the upper and lower limits of the reactive power, so as to form an inner and outer double closed-loop to maintain the stable operation of the voltage of the entire field. In addition, considering the voltage-reactive function of the specific model and the current reactive operating condition of the wind turbine, the current wind turbine side voltage and actual reactive output are combined to calculate the additional inductive reactive power value and the additional capacitive reactive power value of the wind turbine under the current operating conditions, and then optimize the inductive reactive power and capacitive reactive power of the wind turbine, eliminating the excessive correction of the inductive / capacitive reactive power of the wind turbine when the actual reactive output is not considered, making the field-level control more stable.

[0143] In one embodiment, referring to Figure 7 , step S22 comprises:

[0144] S221, the fan side voltage value U within the preset time period Δt WT The filtering voltage U is obtained by filtering.

[0145] S222, based on the wind turbine side voltage safety upper limit The difference between the filter voltage U and the current generator side voltage ΔU up .

[0146] S223, according to the relationship function Q=f(U) between the wind turbine side reactive power and voltage and the current wind turbine side voltage rise ΔU up , get the current additional inductive reactive power value ΔQ up .

[0147] S224, obtain the wind turbine reactive power feedback value Q WT And the current inductive reactive power value that can be increased ΔQ up The sum of .

[0148] S225, the sum passes through zero and the available inductive reactive power The available inductive reactive power of the wind turbine after the optimized limiting

[0149] Among them, the relationship function Q=f(U) between the reactive power Q and the voltage U on the wind turbine side is actually an inverse function of voltage and reactive power, which can be obtained by testing various types of wind turbines in various application environments. Multiple single-machine tests can be performed on multiple wind turbines multiple times, and the reactive power command can be changed to make the wind turbine respond and record the changes in the voltage on the machine side. The relationship between voltage and reactive power is mapped according to the actual test conditions to obtain the function U=f(Q) as the voltage-reactive function for determining the model.

[0150] In one embodiment, referring to Figure 8 , step S22 further includes:

[0151] S226, obtain the voltage safety lower limit on the fan side The difference between the filtered voltage U and the current generator side voltage drop ΔU down .

[0152] S227, according to the relationship function Q=f(U) and the current generator side voltage drop ΔU down , obtain the current capacitive reactive power value ΔQ that can be increased down .

[0153] S228, obtain the wind turbine reactive power feedback value Q WT and the current capacitive reactive power value that can be increased ΔQ down The sum of .

[0154] S229, the sum passes through zero and the available capacitive reactive power Available capacitive reactive power of wind turbine after optimized limiting

[0155] If the updated wind turbine side voltage safety lower limit is greater than zero, the optimized capacitive reactive power of the wind turbine is equal to zero.

[0156] The following two examples are used to introduce the implementation process of the wind farm reactive power control method.

[0157] Example 1

[0158] Taking the whole field reactive power closed loop as the control target, the implementation process is as follows:

[0159] (1) Obtain the voltage value U on the fan side WT , filtering the voltage within a preset time period Δt through a filter to obtain a filtered voltage U;

[0160] (2) The safe upper limit of the fan side voltage for stable operation of the fan side Subtract the filtered voltage U to get the current generator-side voltage that can be increased ΔU up , the fan side voltage safety lower limit for stable operation of the fan side Subtract the filtered voltage U to get the current generator side voltage drop ΔU down ;

[0161] (3) According to the relationship function between the reactive power Q and the voltage U on the wind turbine side, the current additional inductive reactive power value ΔQ is obtained. up and the current additional capacitive reactive power value ΔQ down ;

[0162] (4) Obtaining the wind turbine reactive power feedback value Q WT ;

[0163] (5) Fan reactive power feedback value Q WT And the current inductive reactive power value that can be increased ΔQ up Add together to get the safe upper limit of the voltage on the fan side The total inductive reactive power generated by the internal fans, or the fan reactive power feedback value Q WT and the current capacitive reactive power value that can be increased ΔQ down Add together to get the safe lower limit of the voltage on the fan side The total capacitive reactive power that can be generated by the internal fans;

[0164] (6) Available inductive reactive power through 0 and the fan The optimized inductive reactive power of the fan after limiting Capacitive reactive power of the fan itself The optimized capacitive reactive power of the wind turbine is obtained after the limit is 0.

[0165] (7) Obtaining the reactive power target value Q of the grid connection point cmd And the grid-connected point reactive power feedback value Q feedback ;

[0166] (8) Obtain the first difference E between the reactive power target value and the feedback value Q ;

[0167] (9) First difference E Q The target voltage value U of the grid connection point required for the whole field is obtained by adding the outer loop PI controller to the feedforward value. cmd ,Feedforward is added in this link to speed up the control speed, and the feedforward value is generally set to 1;

[0168] (10) Grid connection point voltage target value U cmd The upper voltage limit U for safe operation through the grid connection point max And the voltage lower limit U min Output grid connection point voltage reference value U after limiting ref ;

[0169] (11) Obtaining the grid-connected point voltage feedback value Ufeedback ;

[0170] (12) Obtain the second difference E between the voltage reference value and the feedback value U ;

[0171] (13) Second difference E U After the inner loop PI controller, the wind turbine group reactive power reference value Q is output ref ;

[0172] (14) Wind turbine group reactive power reference value Q ref The upper limit of reactive power reference Q of wind turbine group max And the wind turbine group reactive power reference lower limit Q min After limiting, subtract the reactive power feedback value Q of the uncontrollable fan Unctrl , output wind turbine group reactive power distribution value Q dist ;

[0173] (15) Based on the optimized available inductive reactive power of the fan and wind turbine available capacitive reactive power Q dist Distribute it to the controllable fans in equal proportion.

[0174] The application prerequisites of Example 1 are shown in the following table.

[0175] Number of fans 20 Rated voltage of grid connection point (kV) 220 Rated capacity(kW) 6250 Reactive power upper limit (kVar) 2000 Reactive power lower limit (kVar) -2000 Rated voltage on the machine side (V) 690

[0176] The application conditions are as follows: the reactive power command of the entire field increases from 0kVar to 40000kVar, then decreases to -40000kVar, and finally returns to 0kVar. The time step for each command issuance is 60s, and the absolute value of each command change is 10000kVar. The impact of the reactive power of the entire field / single machine on the grid connection point / machine side voltage is simulated, and an initial disturbance is added to the machine side voltage of each wind turbine.

[0177] Fig. 9 The following is a comparison of the reactive power control curves of the entire field before and after the application of Example 1, including the reactive power response of the entire field and the voltage change at the grid connection point. It can be seen from the curve comparison that this example can ensure that when the reactive power command is too large, the cascade reactive power PI control can achieve timely protection of the entire field voltage and maintain the grid connection point voltage within a safe range. Figure 5 The optimization results of the upper and lower limits of the reactive capacity of the three typical wind turbines extracted after the application of this example, the reactive power set value issued by the field control, the actual reactive power response of the wind turbine and the machine-side voltage change diagram.

[0178] pass Fig.10 , Fig.11 and Fig.12 The comparison shows that:

[0179] (1) This example can optimize the upper and lower limits of the wind turbine's reactive power response based on the current wind turbine's side voltage and reactive power output.

[0180] (2) Through proportional distribution, field control can reduce the reactive power distribution value to the wind turbine when the voltage on the wind turbine side approaches the safe voltage, thereby ensuring the safe operation of the voltage on the wind turbine side.

[0181] (3) Considering the optimization method of the current reactive power output can effectively avoid the fluctuation of the reactive setting value.

[0182] Example 2

[0183] (1) Obtain the voltage value U on the fan side WT , filtering the voltage within a preset time period Δt through a filter to obtain a filtered voltage U;

[0184] (2) The safe upper limit of the fan side voltage for stable operation of the fan side Subtract the filtered voltage U to get the current generator side voltage that can be increased ΔU up , the fan side voltage safety lower limit for stable operation of the fan side Subtract the filtered voltage U to get the current generator side voltage drop ΔU down ;

[0185] (3) According to the relationship function between the reactive power Q and the voltage U on the wind turbine side, the current additional inductive reactive power value ΔQ is obtained. up and the current additional capacitive reactive power value ΔQ down ;

[0186] (4) Obtain the wind turbine reactive power feedback value Q WT ;

[0187] (5) Fan reactive power feedback value Q WT And the current inductive reactive power value that can be increased ΔQ up Add together to get the safe upper limit of the voltage on the fan side The total inductive reactive power generated by the internal fans, or the fan reactive power feedback value Q WT and the current capacitive reactive power value ΔQ that can be increased down Add together to get the lower limit of the voltage safety on the wind turbine side The total capacitive reactive power that can be generated by the internal fans;

[0188] (6) Available inductive reactive power through 0 and the fan The optimized inductive reactive power of the fan after limiting Capacitive reactive power of the fan itself The optimized capacitive reactive power of the wind turbine is obtained after the limit is 0.

[0189] (7) Obtaining the target voltage value U at the grid connection point cmd , the upper voltage limit U for safe operation through the grid connection point max And the voltage lower limit U min Output grid connection point voltage reference value U after limiting ref ;

[0190] (8) Obtaining the grid-connected point voltage feedback value U feedback ;

[0191] (9) Obtain the second difference E between the voltage reference value and the feedback value U ;

[0192] (10) Second difference E U After the inner loop PI controller, the wind turbine group reactive power reference value Q is output ref ;

[0193] (11) Reactive power reference value Q ref The reactive power reference upper limit Q max And the lower limit of reactive power reference Q min After limiting, subtract the reactive power feedback value Q of the uncontrollable fan Unctrl , output wind turbine group reactive power distribution value Q dist ;

[0194] (12) According to the optimized fan inductive reactive power and wind turbine capacitive reactive power Q dist Distribute it to the controllable fans in equal proportion.

[0195] Example 2

[0196] This embodiment provides a wind farm reactive power control device, referring to Fig.13A The wind farm reactive power control device is used to realize reactive power control, and includes: a voltage closed-loop control module 20.

[0197] The voltage closed-loop control module 20 includes an inner-loop PI controller 21 for limiting the voltage in the inner loop and performing reactive power distribution of a single wind turbine according to the limited voltage.

[0198] The voltage closed-loop control module 20 receives the voltage target value, the grid-connected point voltage feedback value and the reactive power feedback value, as well as the upper and lower limits of the grid-connected point voltage, and outputs the reactive power distribution value of the wind turbine group based on the voltage target value, the grid-connected point voltage feedback value and the reactive power feedback value, as well as the upper and lower limits of the grid-connected point voltage.

[0199] In this embodiment, through the voltage closed-loop control of the inner loop, the voltage on the wind turbine side is ensured not to exceed the limit under the condition of a clear voltage target value, so as to maintain the stable operation of the voltage of the whole field; based on the series reactive PI control, the reactive power closed-loop control considering the voltage of the grid point is realized, and the reactive power closed-loop control includes the voltage closed-loop control of the inner loop. The inner loop of the voltage closed-loop control is embedded in the reactive power closed-loop control. Taking into account the influence of the reactive output of the wind turbine on the voltage of the whole field, the series reactive PI control is adopted to reasonably allocate the reactive output of the wind turbine under the constraints of the upper and lower limits of the grid point voltage and the upper and lower limits of the reactive power, so as to form an inner and outer double closed-loop to maintain the stable operation of the voltage of the whole field. In addition, considering the voltage-reactive function of the specific model and the current reactive operating condition of the wind turbine, the current wind turbine side voltage and actual reactive output are combined to calculate the additional inductive reactive power value and the additional capacitive reactive power value of the wind turbine under the current operating conditions, and then optimize the inductive reactive power and capacitive reactive power of the wind turbine, eliminating the excessive correction of the inductive / capacitive reactive power of the wind turbine when the actual reactive output is not considered, making the field-level control more stable.

[0200] In one embodiment, the wind farm reactive power control device further includes: a reactive power closed-loop control module 30 .

[0201] The reactive power closed-loop control module 30 includes an outer-loop PI controller 31, which is used to obtain the voltage target value based on the reactive power target value of the grid connection point and the reactive power feedback value of the entire field.

[0202] In one embodiment, the voltage closed-loop control module 20 further includes: a first limiter 22 , a second limiter 23 , a first adder 24 and a second adder 25 .

[0203] The input end of the first limiter 22 is connected to the voltage target value, the control end of the first limiter 22 is respectively connected to the voltage upper limit and the voltage lower limit, the output end of the first limiter 22 outputs the grid-connected point voltage reference value to the first input end of the first adder 24, the second input end of the first adder 24 is connected to the inverted grid-connected point voltage feedback value, and the output end of the first adder 24 outputs the second difference to the input end of the inner loop PI controller 21.

[0204] The output end of the inner loop PI controller 21 outputs the reactive power reference value of the wind turbine group to the input end of the second limiter 23. The control end of the second limiter 23 is respectively connected to the upper limit and the lower limit of the reactive power of the whole field. The output end of the second limiter 23 is connected to the first input end of the second adder 25. The second input end of the second adder 25 is connected to the reactive power feedback value of the reversed uncontrollable wind turbine.

[0205] The output end of the second adder 25 outputs the reactive power distribution value of the wind turbine group.

[0206] In one embodiment, the reactive power closed-loop control module 30 further includes: a third adder 32 and a fourth adder 33 .

[0207] The first input end of the third adder 32 is connected to the reactive power target value of the grid connection point, the second input end of the third adder 32 is connected to the inverted full-field reactive power feedback value, and the output end of the third adder 32 outputs the first difference to the input end of the outer loop PI controller 31.

[0208] The output end of the outer loop PI controller 31 is connected to the first input end of the fourth adder 33 , the second input end of the fourth adder 33 is connected to the feedforward value, and the output end of the fourth adder 33 outputs the voltage target value.

[0209] Example 3

[0210] Corresponding to the aforementioned embodiment of the reactive power control method of a wind farm, the present disclosure also provides an embodiment of a reactive power control system of a wind farm.

[0211] Fig. 13B A module schematic diagram of a wind farm reactive power control system provided by an exemplary embodiment of the present disclosure includes: an acquisition module 1, a reactive power closed-loop control module 2, a reactive proportional distribution module 3 and a sending module 4.

[0212] The acquisition module 1 is used to obtain the grid connection point voltage target value, the grid connection point voltage feedback value and the reactive power feedback value.

[0213] The reactive power closed-loop control module 2 is used to adopt double-loop PI control and obtain the reactive power distribution value of the wind turbine group based on the grid connection point voltage target value, grid connection point voltage feedback value and reactive power feedback value to maintain the stability of the grid connection point voltage.

[0214] The reactive power proportional distribution module 3 is used to perform proportional distribution according to the reactive power distribution value of the wind turbine group and the reactive power output capacity of each wind turbine to obtain the reactive power target value of the controllable wind turbine.

[0215] The sending module 4 is used to send the reactive power target value of the controllable wind turbine to each wind turbine group, so that the wind turbine group responds to the corresponding reactive power target value.

[0216] In this embodiment, through the inner loop voltage closed-loop control, the voltage on the wind turbine side is ensured not to exceed the limit while the grid-connected point voltage target value is clear, so as to maintain the stable operation of the grid-connected point voltage; based on the series reactive PI control, the reactive power closed-loop control of the grid-connected point voltage is considered, and the reactive power closed-loop control includes the inner loop voltage closed-loop control. The inner loop of the voltage closed-loop control is embedded in the reactive power closed-loop control. Taking into account the impact of the wind turbine reactive output on the whole field voltage, the series reactive PI control is adopted to reasonably allocate the wind turbine reactive output under the constraints of the upper and lower limits of the grid-connected point voltage and the upper and lower limits of the reactive power, so as to form an inner and outer double closed-loop to maintain the stable operation of the grid-connected point voltage.

[0217] In one embodiment, the acquisition module 1 is further used to obtain the reactive power target value of the grid connection point and the reactive power feedback value of the grid connection point;

[0218] The acquisition module 1 is also used based on the reactive power target value of the grid connection point and the reactive power feedback value of the grid connection point.

[0219] The acquisition module 1 is also used to adopt outer loop PI control and obtain the grid connection point voltage target value based on the grid connection point reactive power target value and the grid connection point reactive power feedback value.

[0220] In one embodiment, the reactive power closed-loop control module 2 is further used to obtain a first difference between the reactive power target value of the grid connection point and the reactive power feedback value of the grid connection point.

[0221] The reactive power closed-loop control module 2 is further used to add the first difference after the outer-loop PI control to a preset feedforward value to obtain a voltage target value.

[0222] In one embodiment, the reactive power closed-loop control module 2 is also used to obtain the upper and lower limits of the grid connection point voltage for safe operation of the grid connection point.

[0223] The reactive power closed-loop control module 2 is also used to limit the grid connection point voltage target value based on the grid connection point voltage upper and lower limits, and use the grid connection point voltage target value after limiting as the grid connection point voltage reference value.

[0224] The reactive power closed-loop control module 2 is further used to obtain a second difference between the grid connection point voltage reference value and the grid connection point voltage feedback value.

[0225] The reactive power closed-loop control module 2 is also used to perform inner-loop PI control on the second difference to obtain a reactive power reference value of the wind turbine group.

[0226] The reactive power closed-loop control module 2 is also used to obtain the upper and lower limits of the reactive power reference value of the wind turbine group, and limit the reactive power reference value of the wind turbine group;

[0227] The reactive power closed-loop control module 2 is further used to obtain the reactive power distribution value of the wind turbine group according to the difference between the reactive power reference value of the wind turbine group and the reactive power feedback value of the uncontrollable wind turbine.

[0228] In one embodiment, the wind farm reactive power control system further includes: a reactive power optimization module 5 .

[0229] The acquisition module 1 is also used to obtain the wind turbine side voltage value, the wind turbine side voltage safety upper limit, the wind turbine side voltage safety lower limit, the wind turbine reactive power feedback value, the wind turbine available inductive reactive power and available capacitive reactive power.

[0230] The reactive capacity optimization module 5 is used to optimize the upper and lower limits of the reactive capacity of the fan based on the fan side voltage value, the fan side voltage safety upper limit, the fan side voltage safety lower limit, the fan reactive power feedback value, the available inductive reactive power and the available capacitive reactive power, and obtain the optimized fan available inductive reactive power and the fan available capacitive reactive power.

[0231] The reactive proportional distribution module 3 is also used to distribute the reactive power distribution value of the wind turbine group among each controllable wind turbine in equal proportion according to the available inductive reactive power of the wind turbine and the available capacitive reactive power of the wind turbine to obtain the reactive power target value of the controllable wind turbine. Among them, the available inductive reactive power of the wind turbine represents the available inductive reactive power of a single wind turbine when the reactive power distribution value of the wind turbine group is a positive value, and the available capacitive reactive power of the wind turbine represents the available capacitive reactive power of a single wind turbine when the reactive power distribution value of the wind turbine group is a negative value.

[0232] In this embodiment, through the voltage closed-loop control of the inner loop, the voltage on the wind turbine side is ensured not to exceed the limit under the condition of a clear voltage target value, so as to maintain the stable operation of the voltage of the whole field; based on the series reactive PI control, the reactive power closed-loop control of the grid-connected point voltage is considered, and the reactive power closed-loop control includes the voltage closed-loop control of the inner loop. The inner loop of the voltage closed-loop control is embedded in the reactive power closed-loop control. Taking into account the influence of the reactive output of the wind turbine on the voltage of the whole field, the series reactive PI control is adopted to reasonably allocate the reactive output of the wind turbine under the constraints of the upper and lower limits of the grid-connected point voltage and the upper and lower limits of the reactive power, so as to form an inner and outer double closed-loop to maintain the stable operation of the voltage of the whole field. In addition, considering the voltage-reactive function of the specific model and the current reactive operating condition of the wind turbine, the current wind turbine side voltage and actual reactive output are combined to calculate the additional inductive reactive power value and the additional capacitive reactive power value of the wind turbine under the current operating conditions, and then optimize the inductive reactive power and capacitive reactive power of the wind turbine, eliminating the excessive correction of the inductive / capacitive reactive power of the wind turbine when the actual reactive output is not considered, making the field-level control more stable.

[0233] In one embodiment, the reactive power optimization module 5 is further configured to filter the voltage value on the fan side within a preset time period to obtain a filtered voltage.

[0234] The reactive capacity optimization module 5 is also used to obtain the current boostable voltage on the wind turbine side based on the difference between the wind turbine side voltage safety upper limit and the filter voltage.

[0235] The reactive power optimization module 5 is also used to obtain the current increaseable inductive reactive power value according to the relationship function between the reactive power and the voltage on the wind turbine side and the current increaseable voltage on the wind turbine side.

[0236] The reactive power optimization module 5 is also used to obtain the sum of the reactive power feedback value of the wind turbine and the current increaseable inductive reactive power value.

[0237] The reactive power optimization module 5 is further used to obtain the optimized available inductive reactive power of the wind turbine by limiting the sum through zero and the available inductive reactive power.

[0238] In one embodiment, the reactive power optimization module 5 is further used to obtain the difference between the wind turbine side voltage safety lower limit and the filter voltage, and use the difference as the current wind turbine side step-down voltage.

[0239] The reactive power optimization module 5 is also used to obtain the current increaseable capacitive reactive power value according to the relationship function and the current machine-side voltage that can be reduced.

[0240] The reactive power optimization module 5 is also used to obtain the sum of the reactive power feedback value of the wind turbine and the current increaseable capacitive reactive power value.

[0241] The reactive power optimization module 5 is further used to obtain the optimized available capacitive reactive power of the wind turbine by limiting the sum through zero and the available capacitive reactive power.

[0242] As for the system embodiment, since it basically corresponds to the method embodiment, the relevant parts can refer to the partial description of the method embodiment. The system embodiment described above is only illustrative, wherein the units described as separate components may or may not be physically separated, and the components as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the disclosed solution.

[0243] Example 4

[0244] Fig.14 This is a structural schematic diagram of an electronic device shown in an example embodiment of the present disclosure, the electronic device includes a memory, a processor, and a computer program stored in the memory and used to run on the processor, and when the processor executes the computer program, the wind farm reactive power control method described in any of the above embodiments is implemented. Fig.14The electronic device 90 shown is only an example and should not bring any limitation to the functions and scope of use of the embodiments of the present disclosure.

[0245] like Fig.14 As shown, the electronic device 90 may be in the form of a general-purpose computing device, for example, it may be a server device. The components of the electronic device 90 may include, but are not limited to: at least one processor 91, at least one memory 92, and a bus 93 connecting different system components (including the memory 92 and the processor 91).

[0246] The bus 93 includes a data bus, an address bus, and a control bus.

[0247] The memory 92 may include a volatile memory, such as a random access memory (RAM) 921 and / or a cache memory 922 , and may further include a read-only memory (ROM) 923 .

[0248] The memory 92 may also include a program tool 925 (or utility) having a set (at least one) of program modules 924, such program modules 924 including but not limited to: an operating system, one or more application programs, other program modules and program data, each of which or some combination may include an implementation of a network environment.

[0249] The processor 91 executes various functional applications and data processing by running the computer program stored in the memory 92, such as the wind farm reactive power control method provided by any of the above embodiments.

[0250] The electronic device 90 may also communicate with one or more external devices 94 (e.g., keyboards, pointing devices, etc.). Such communication may be performed via an input / output (I / O) interface 95. Furthermore, the electronic device 90 may also communicate with one or more networks (e.g., local area networks (LANs), wide area networks (WANs), and / or public networks, such as the Internet) via a network adapter 96. As shown, the network adapter 96 communicates with other modules of the electronic device 90 via a bus 93. It should be understood that, although not shown in the figure, other hardware and / or software modules may be used in conjunction with the electronic device 90, including but not limited to: microcode, device drivers, redundant processors, external disk drive arrays, RAID (disk array) systems, tape drives, and data backup storage systems, etc.

[0251] It should be noted that although several units / modules or sub-units / modules of the electronic device are mentioned in the above detailed description, this division is merely exemplary and not mandatory. In fact, according to the embodiments of the present disclosure, the features and functions of two or more units / modules described above can be embodied in one unit / module. Conversely, the features and functions of one unit / module described above can be further divided into multiple units / modules to be embodied.

[0252] Example 5

[0253] The embodiments of the present disclosure further provide a computer-readable storage medium having a computer program stored thereon, and when the program is executed by a processor, the method for controlling reactive power of a wind farm provided in any of the above embodiments is implemented.

[0254] The readable storage medium may include but is not limited to: a portable disk, a hard disk, a random access memory, a read-only memory, an erasable programmable read-only memory, an optical storage device, a magnetic storage device or any suitable combination of the above.

[0255] Example 6

[0256] The embodiments of the present disclosure further provide a computer program product, including a computer program, which implements any of the wind farm reactive power control methods described above when executed by a processor.

[0257] Among them, the program code for executing the computer program product of the present disclosure can be written in any combination of one or more programming languages, and the program code can be executed completely on the user device, partially on the user device, as an independent software package, partially on the user device and partially on a remote device, or completely on the remote device.

[0258] Although the specific embodiments of the present disclosure are described above, those skilled in the art should understand that this is only an example, and the protection scope of the present disclosure is defined by the appended claims. Those skilled in the art may make various changes or modifications to these embodiments without departing from the principles and essence of the present disclosure, but these changes and modifications all fall within the protection scope of the present disclosure.

Claims

1. A method for controlling reactive power of a wind farm, characterized in that: The wind farm reactive power control method is at least used to achieve closed-loop control of reactive power and voltage at a wind farm grid connection point, and includes: Obtaining the grid connection point voltage target value, reactive power feedback value and grid connection point voltage feedback value; Based on the grid connection point voltage target value, the reactive power feedback value and the grid connection point voltage feedback value, as well as the upper and lower limits of the grid connection point voltage, a double-loop PI control is adopted to obtain a reactive power distribution value of the wind turbine group; The reactive power target value of each controllable wind turbine is obtained by performing proportional distribution according to the reactive power distribution value of the wind turbine group and the reactive power output capacity of each wind turbine; The reactive power target value of the controllable wind turbine is sent to each wind turbine group, so that the wind turbine group responds to the corresponding reactive power target value.

2. The wind farm reactive power control method according to claim 1, characterized in that: The obtaining of the grid connection point voltage target value comprises: Obtain the reactive power target value and reactive power feedback value of the grid connection point Based on the reactive power target value of the grid connection point and the reactive power feedback value of the grid connection point, outer loop PI control is adopted to obtain the grid connection point voltage target value.

3. The wind farm reactive power control method according to claim 2, characterized in that: The method of adopting outer loop PI control and obtaining the grid connection point voltage target value based on the grid connection point reactive power target value and the grid connection point reactive power feedback value comprises: Obtaining a first difference between the reactive power target value of the grid connection point and the reactive power feedback value of the grid connection point; The first difference is added to a preset feedforward value after being controlled by the outer loop PI to obtain the grid connection point voltage target value.

4. The wind farm reactive power control method according to claim 1, characterized in that: The method adopts double-loop PI control and obtains the reactive power distribution value of the wind turbine group based on the grid connection point voltage target value, the grid connection point voltage feedback value and the reactive power feedback value, as well as the upper and lower limits of the grid connection point voltage, including: Obtaining the upper and lower limits of the grid connection point voltage; Based on the upper and lower limits of the grid connection point voltage, the grid connection point voltage target value is limited, and the voltage target value after limiting is used as the grid connection point voltage reference value; Obtaining a second difference between the grid connection point voltage reference value and the grid connection point voltage feedback value; Performing inner loop PI control on the second difference to obtain a reactive power reference value of the wind turbine group; Obtaining upper and lower limits of reactive power reference values ​​of a wind turbine group, and limiting the reactive power reference values ​​of the wind turbine group; The reactive power distribution value of the wind turbine group is obtained according to the difference between the reactive power reference value of the wind turbine group and the reactive power feedback value of the uncontrollable wind turbine.

5. The wind farm reactive power control method according to claim 1, characterized in that: Before the step of performing reactive power proportional distribution according to the reactive power distribution value of the wind turbine group to obtain the reactive power target value of each controllable wind turbine, the wind farm reactive power control method further includes: Obtain the fan side voltage value, the fan side voltage safety upper limit, the fan side voltage safety lower limit, the fan reactive power feedback value, the fan available inductive reactive power and available capacitive reactive power; Based on the wind turbine side voltage value, the wind turbine side voltage safety upper limit, the wind turbine side voltage safety lower limit, the wind turbine reactive power feedback value, the available inductive reactive power and the available capacitive reactive power, the available inductive reactive power and the available capacitive reactive power are optimized to obtain the optimized wind turbine available inductive reactive power and the wind turbine available capacitive reactive power; The reactive power target value of each controllable wind turbine is obtained by performing proportional distribution according to the reactive power distribution value of the wind turbine group, including: According to the optimized available inductive reactive power of the wind turbine and the available capacitive reactive power of the wind turbine, the reactive power distribution value of the wind turbine group is distributed equally among the controllable wind turbines to obtain the reactive power target value of the controllable wind turbine.

6. The wind farm reactive power control method according to claim 5, characterized in that: The optimization of available inductive reactive power and available capacitive reactive power to obtain optimized available inductive reactive power and available capacitive reactive power of the wind turbine includes: Filtering the fan side voltage value within a preset time period to obtain a filtered voltage; Obtaining the current boostable voltage on the fan side based on the difference between the fan side voltage safety upper limit and the filter voltage; According to the relationship function between the reactive power and the voltage on the wind turbine side and the current increaseable voltage on the wind turbine side, the current increaseable inductive reactive power value is obtained; Obtaining the sum of the wind turbine reactive power feedback value and the current increaseable inductive reactive power value; The sum is passed through zero and the available inductive reactive power is limited to obtain the optimized available inductive reactive power of the wind turbine.

7. The wind farm reactive power control method according to claim 6, characterized in that: The step of optimizing the available inductive reactive power and the available capacitive reactive power to obtain the optimized available inductive reactive power and the available capacitive reactive power of the wind turbine also includes: Obtaining a difference between the wind turbine side voltage safety lower limit and the filter voltage, and using the difference as the current wind turbine side drop-able voltage; According to the relationship function and the current machine-side voltage that can be reduced, a current value of capacitive reactive power that can be increased is obtained; Obtaining the sum of the wind turbine reactive power feedback value and the current increaseable capacitive reactive power value; The sum is passed through zero and the available capacitive reactive power is limited to obtain the optimized available capacitive reactive power of the wind turbine.

8. A wind farm reactive power control device, characterized in that: The wind farm reactive power control device is used to realize reactive power control, and includes: a voltage closed-loop control module; The voltage closed-loop control module includes an inner-loop PI controller, which is used to limit the target voltage value of the grid connection point in the inner loop, and distribute the reactive power of the wind turbine according to the voltage target value after limiting; The voltage closed-loop control module is connected to the grid connection point voltage target value, the grid connection point voltage feedback value and the grid connection point voltage upper and lower limits, and outputs the wind turbine group reactive power distribution value based on the grid connection point voltage target value, the grid connection point voltage feedback value and the grid connection point voltage upper and lower limits.

9. The wind farm reactive power control device according to claim 8, characterized in that: The wind farm reactive power control device further comprises: a reactive power closed-loop control module; The reactive power closed-loop control module includes an outer-loop PI controller, which is used to obtain the grid connection point voltage target value based on the grid connection point reactive power target value and the grid connection point reactive power feedback value.

10. The wind farm reactive power control device according to claim 8, characterized in that: The voltage closed-loop control module further includes: a first limiter, a second limiter, a first adder and a second adder; The input end of the first limiter is connected to the grid connection point voltage target value, the control end of the first limiter is respectively connected to the preset grid connection point voltage upper limit and voltage lower limit, the output end of the first limiter outputs the grid connection point voltage reference value to the first input end of the first adder, the second input end of the first adder is connected to the inverted grid connection point voltage feedback value, and the output end of the first adder outputs the second difference to the input end of the inner loop PI controller; The output end of the inner loop PI controller outputs the reactive power reference value of the wind turbine group to the input end of the second limiter, the control end of the second limiter is respectively connected to the upper limit of the reactive power of the wind turbine group and the lower limit of the reactive power of the wind turbine group, the output end of the second limiter is connected to the first input end of the second adder, and the second input end of the second adder is connected to the reactive power feedback value of the inverted uncontrollable wind turbine; The output end of the second adder outputs the reactive power distribution value of the wind turbine group.

11. The wind farm reactive power control device according to claim 9, characterized in that: The reactive power closed-loop control module further includes: a third adder and a fourth adder; The first input end of the third adder is connected to the grid-connected point reactive power target value, the second input end of the third adder is connected to the inverted grid-connected point reactive power feedback value, and the output end of the third adder outputs the first difference to the input end of the outer loop PI controller; The output end of the outer loop PI controller is connected to the first input end of the fourth adder, the second input end of the fourth adder is connected to the feedforward value, and the output end of the fourth adder outputs the grid connection point voltage target value.

12. A wind farm reactive power control system, characterized in that: The wind farm reactive power control system is at least used to realize voltage closed-loop control, and includes: an acquisition module, a reactive power closed-loop control module, a reactive proportional distribution module and a transmission module; The acquisition module is used to obtain the grid connection point voltage target value, the grid connection point voltage feedback value and the reactive power feedback value; The reactive power closed-loop control module is used to adopt double-loop PI control and obtain the reactive power distribution value of the wind turbine group based on the grid connection point voltage target value, the grid connection point voltage feedback value and the grid connection point reactive power feedback value, as well as the grid connection point voltage upper and lower limits; The reactive power proportional distribution module is used to perform proportional distribution according to the reactive power distribution value of the wind turbine group and the reactive power output capacity of each wind turbine to obtain the reactive power target value of the controllable wind turbine; The sending module is used to send the reactive power target value of the controllable wind turbine to each wind turbine group, so that the wind turbine group responds to the corresponding reactive power target value.

13. An electronic device comprising a memory, a processor, and a computer program stored in the memory and used to run on the processor, characterized in that: When the processor executes the computer program, the wind farm reactive power control method according to any one of claims 1 to 7 is implemented.

14. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the wind farm reactive power control method according to any one of claims 1 to 7 is implemented.

15. A computer program product comprising a computer program, characterized in that When the computer program is executed by a processor, the wind farm reactive power control method according to any one of claims 1 to 7 is implemented.

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