Voltage-reactive power adaptive optimization control method, system, equipment and medium

Abstract

The present invention belongs to the technical field of photovoltaic inverters, and specifically relates to a voltage-reactive adaptive optimization control method and system, equipment and medium. In view of the shortcomings that when the inverter in the existing photovoltaic system participates in voltage regulation, the droop coefficient is fixed or the adjustment strategy does not take into account the operating status of the distribution network and the source-load fluctuation, and the voltage regulation effect is not ideal, the present invention adopts the following technical scheme: The voltage-reactive adaptive optimization control method includes: performing a primary adjustment, recording various parameters before, after and during the start of the primary adjustment; performing a secondary adjustment; calculating the reactive power change of the inverter; calculating the reactive reference value; calculating the voltage-reactive droop coefficient according to the obtained reactive reference value and the target voltage of the grid connection point, and adjusting the voltage-reactive curve according to the new droop coefficient, and controlling the inverter to perform secondary adjustment. The beneficial effect of the present invention is that the grid droop coefficient still changes according to the current voltage and grid operation conditions, and the voltage over-limit suppression effect is more obvious.

Description

Technical Field

[0001] The present invention belongs to the technical field of photovoltaic inverters, and in particular relates to a voltage-reactive power adaptive optimization control method and system, equipment and medium. Background Art

[0002] As the penetration rate of photovoltaic power increases, photovoltaic power generation may exceed the load power, resulting in power backflow to the transmission network, which will lead to serious overvoltage problems, seriously threatening the power quality and power supply reliability of the distribution network, and restricting the further development of distributed photovoltaic power. The dynamic reactive power compensation device installed in the distribution network can suppress the overvoltage problem, but this will reduce the economic efficiency of the power grid. The photovoltaic grid-connected inverter itself can output reactive power. Making full use of the reactive power of the inverter to control the voltage can improve the voltage support capacity of distributed photovoltaic power.

[0003] Traditional voltage control methods rely on local information and use voltage-reactive power curve control. By measuring the voltage at the photovoltaic grid-connected point, the reactive power reference value that the inverter needs to absorb or emit is calculated according to the voltage-reactive power curve, and the output of reactive power is dynamically adjusted to achieve the effect of voltage control. However, the voltage control effect is affected by the droop slope of the voltage-reactive power curve. Under normal circumstances, the droop coefficient is a certain value, and the voltage-reactive power curve is fixed. If the droop slope is not selected to adapt to the voltage change of the distribution network, it will affect the voltage-reactive power control. In addition, different photovoltaic access locations / distribution network operation conditions will also have different requirements for the droop slope. Improper setting of the droop coefficient may cause the reactive power of the photovoltaic inverter to not be fully utilized, limiting the voltage support capacity of the photovoltaic inverter.

[0004] In view of the different photovoltaic access locations, some literature has proposed using voltage-reactive sensitivity to obtain the droop slope of different access points. However, this method requires knowledge of the entire distribution network line information, which increases the complexity of control and does not consider the impact of the load. It is possible that the calculated voltage-reactive curve cannot adapt to changes in the power grid.

[0005] In view of the operation of the distribution network, some literatures have proposed to change the voltage-reactive power droop coefficient according to the grid connection point voltage, but the regulation time of the droop coefficient does not match the voltage change time, and the overvoltage suppression effect is questionable. Some solutions also use segmented voltage-reactive power control curves to update the droop control coefficient at a certain frequency (minute level) according to the grid connection point voltage segment, but these solutions do not optimize the voltage-reactive power control curve according to the photovoltaic inverter's own state and regulation capability, the distribution network operation characteristics and scenario requirements, fail to fully utilize the inverter's reactive power regulation capacity, and the suppression effect on the rapidly changing grid voltage fluctuations is not ideal.

[0006] In short, the existing voltage-reactive power control droop coefficient is fixed or the adjustment strategy does not take into account the operating status of the distribution network and source-load fluctuations, and the voltage regulation effect is not ideal. Summary of the invention

[0007] The present invention aims at the problem that when the inverter in the existing photovoltaic system participates in voltage regulation, the droop coefficient is fixed or the adjustment strategy does not take into account the operating state of the distribution network and the source-load fluctuation, resulting in an unsatisfactory voltage regulation effect. The present invention also provides a voltage-reactive adaptive optimization control system, equipment and medium.

[0008] To achieve the above object, the present invention adopts the following technical solution: a voltage-reactive power adaptive optimization control method, the voltage-reactive power adaptive optimization control method comprising:

[0009] Step S1, obtaining the grid connection point voltage in real time, comparing the absolute value of the voltage difference between the current grid connection point voltage and the preset grid connection point target voltage with the preset voltage threshold, and controlling the inverter to perform an adjustment when the absolute value of the voltage difference is greater than the preset voltage threshold;

[0010] Step S2, recording the instantaneous reactive power of the inverter at the beginning of the primary adjustment, the instantaneous voltage of the grid connection point when the primary adjustment is completed, the instantaneous reactive power of the inverter when the primary adjustment is completed, and the maximum voltage of the grid connection point during the primary adjustment stage, and judging whether the instantaneous voltage of the current grid connection point meets the requirements when the primary adjustment is completed, and performing secondary adjustment if it does not meet the requirements;

[0011] Step S3, calculating the required inverter reactive power change according to the instantaneous voltage at the grid connection point when the primary adjustment is completed, the target voltage at the grid connection point, and the voltage change and reactive power change during the primary adjustment process;

[0012] Step S4, calculating a reactive power reference value according to the instantaneous reactive power of the inverter at the beginning of a regulation and the calculated reactive power change of the inverter;

[0013] Step S5: Calculate the voltage-reactive power droop coefficient according to the obtained reactive power reference value and the target voltage of the grid connection point, adjust the voltage-reactive power curve according to the new droop coefficient, and control the inverter to perform secondary regulation.

[0014] As an improvement, in step S1, the grid connection point voltage at the current moment is assumed to be U, and the grid connection point target voltage is , the preset voltage threshold is ε1, and the absolute value of the voltage difference |u|=|U ref -U|, compare |u| with ε1, and control the inverter to adjust when the absolute value of the voltage difference |u| is greater than the preset voltage threshold ε1.

[0015] As an improvement, in step S2, the absolute value of the reactive difference between the inverter reactive power at the current moment and the reference reactive power of the primary regulating inverter is compared with a preset reactive threshold. When the absolute value of the reactive difference is less than or equal to the preset reactive threshold, it indicates that the primary regulation is completed. The reference reactive power of the primary regulating inverter is obtained based on the preset grid-connected point target voltage and the current voltage-reactive curve.

[0016] As an improvement, in step S2, the reactive power of the inverter at the current moment is assumed to be Q, and the reference reactive power of the inverter is adjusted to be , the preset reactive power threshold is ε2, and the absolute value of reactive power difference DQ=|Q ref -Q|, compare DQ with ε2;

[0017] The signal when DQ≤ε2 is marked as ks_t=0, the signal when DQ>ε2 is marked as ks_t=1, and the signal at the previous moment is recorded as ks_t-1;

[0018] When ks_t-1=0, ks_t=1, the reactive power of the inverter at this time is recorded as the instantaneous reactive power Q1 of the inverter at the beginning of the primary regulation;

[0019] When ks_t-1=1 and ks_t=0, the reactive power of the inverter is measured as the instantaneous reactive power Q2 of the inverter when the primary regulation is completed. At this time, the voltage of the photovoltaic grid-connected point is measured as U min ;

[0020] The maximum voltage of the grid connection point in the ks_t=1 stage is U max .

[0021] As an improvement, in step S2, the magnitude of |u| and ε1 is also compared to determine whether the instantaneous voltage at the grid connection point meets the requirement when one adjustment is completed.

[0022] As an improvement, in step S3, the target voltage at the grid connection point is reached. Required inverter reactive power change The calculation formula is:

[0023]

[0024]

[0025] .

[0026] As an improvement, in step S4, the reactive power reference value The calculation formula is:

[0027] .

[0028] As an improvement, in step S5, the voltage-reactive power droop coefficient K The calculation formula is:

[0029] .

[0030] A voltage-reactive power adaptive optimization control system is used to implement the aforementioned voltage-reactive power adaptive optimization control method, and the voltage-reactive power adaptive optimization control system includes:

[0031] The voltage acquisition module is used to obtain the grid connection point voltage in real time, including the instantaneous voltage of the grid connection point when the primary regulation is completed and the maximum voltage of the grid connection point during the regulation stage;

[0032] A threshold comparison module, used to compare the absolute value of the voltage difference between the grid connection point voltage at the current moment and the preset grid connection point target voltage with a preset threshold;

[0033] A reactive power acquisition module is used to acquire the instantaneous reactive power of the inverter when a regulation starts;

[0034] The voltage-reactive power curve module is used to obtain the reference reactive power of the inverter when the primary regulation is completed according to the preset grid connection point target voltage and voltage-reactive power curve;

[0035] A primary regulation module, used for controlling the inverter to perform primary regulation according to the reference reactive power of the inverter when the primary regulation is completed when the absolute value of the voltage difference is greater than a preset threshold value;

[0036] The reactive power variation calculation module is used to calculate the required inverter reactive power variation according to the instantaneous voltage at the grid connection point when the primary regulation is completed, the target voltage at the grid connection point, and the voltage variation and reactive power variation during the primary regulation process;

[0037] A reactive reference value calculation module is used to calculate a reactive reference value according to the instantaneous reactive power of the inverter at the beginning of a primary regulation and the calculated reactive power change of the inverter;

[0038] A voltage-reactive power droop coefficient updating module is used to calculate the voltage-reactive power droop coefficient according to the calculated reactive power reference value;

[0039] The secondary regulation module is used to adjust the voltage-reactive power curve according to the new droop coefficient and control the inverter to perform secondary regulation.

[0040] The computer device includes a processor and a storage medium. The storage medium stores a computer program. When the computer program is executed by the processor, the aforementioned voltage-reactive power adaptive optimization control method is implemented.

[0041] A computer-readable storage medium stores a computer program, which, when executed, implements the aforementioned voltage-reactive power adaptive optimization control method.

[0042] The beneficial effect of the voltage-reactive adaptive optimization control method of the present invention is: when the voltage after the first adjustment is completed still does not meet the requirements, a secondary adjustment is performed; during the secondary adjustment, the required inverter reactive power change is calculated according to the instantaneous voltage of the grid connection point when the first adjustment is completed (also the initial voltage during the second adjustment), the target voltage of the grid connection point, and the voltage change and reactive change during the first adjustment process, and then the reactive reference value is obtained, and finally a new droop coefficient is obtained, that is, the droop coefficient changes dynamically according to the previous adjustment situation, so that it can automatically adapt to the operating state of the distribution network and the source-load fluctuation, and has good applicability. Usually, the requirements can be met after the second adjustment. When the requirements are still not met after the second adjustment, the relevant steps are repeated. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 It is a schematic diagram of the structure of a distributed photovoltaic system in a distribution network and a photovoltaic control block diagram of an embodiment of the present invention.

[0044] Figure 2 It is a flow chart of the voltage-reactive power adaptive optimization control method according to an embodiment of the present invention.

[0045] Figure 3 It is a block diagram for judging the reactive power regulation state of the inverter according to an embodiment of the present invention.

[0046] Figure 4 It is a block diagram of actual reactive power and grid-connected point voltage at the beginning of primary regulation of the inverter according to an embodiment of the present invention.

[0047] Figure 5 It is a block diagram of actual reactive power and grid-connected point voltage when the inverter of an embodiment of the present invention completes primary regulation.

[0048] Figure 6 It is a block diagram for calculating the voltage-reactive power curve droop coefficient according to an embodiment of the present invention.

[0049] Figure 7 This is a result diagram obtained by controlling a voltage-reactive power curve with a fixed curve slope.

[0050] Figure 8 It is a result diagram obtained by controlling a voltage-reactive curve selected according to voltage using a curve slope.

[0051] Fig. 9 This is a result diagram obtained by controlling the voltage-reactive power curve with the adaptive droop coefficient according to the embodiment of the present invention. DETAILED DESCRIPTION

[0052] The technical solutions of the embodiments of the present invention are explained and described below, but the following embodiments are only preferred embodiments of the present invention, not all. Based on the embodiments in the implementation mode, other embodiments obtained by those skilled in the art without creative work are all within the protection scope of the present invention.

[0053] In order to better illustrate the voltage-reactive power adaptive optimization control method of the embodiment of the present invention, the existing distributed photovoltaic distribution network system is first introduced. Figure 1 An existing distributed photovoltaic distribution network system includes a power grid, a transformer (OLTC is a core component of the transformer), a line, a load and distributed photovoltaic ( i , j , k ). Each photovoltaic uses grid-following control, and the control system consists of a voltage loop, a power loop, and a current loop. PV stands for photovoltaic.

[0054] Each photovoltaic system adopts local control. For the sake of simplicity, a photovoltaic k In photovoltaic k middle, V abc is the three-phase voltage at the grid-connected point, Q is the reactive power absorbed / generated by the inverter, and the subscripts “d” and “q” are the d-axis and q-axis components, respectively. Figure 1 The content in the box is the existing photovoltaic control method.

[0055] See also Figure 2 The voltage-reactive power multi-scenario adaptive optimization control method of the embodiment of the present invention includes:

[0056] Step S1, obtaining the grid connection point voltage in real time, comparing the absolute value of the voltage difference between the current grid connection point voltage and the preset grid connection point target voltage with the preset voltage threshold, and controlling the inverter to perform an adjustment when the absolute value of the voltage difference is greater than the preset voltage threshold;

[0057] Step S2, after the primary adjustment is completed, record the instantaneous reactive power of the inverter at the beginning of the primary adjustment, the instantaneous voltage of the grid connection point when the primary adjustment is completed, the instantaneous reactive power of the inverter when the primary adjustment is completed, and the maximum voltage of the grid connection point during the primary adjustment stage. When the primary adjustment is completed, determine whether the instantaneous voltage of the current grid connection point meets the requirements. If not, perform secondary adjustment;

[0058] Step S3, calculating the required inverter reactive power change according to the instantaneous voltage at the grid connection point when the primary adjustment is completed, the target voltage at the grid connection point, and the voltage change and reactive power change during the primary adjustment process;

[0059] Step S4, calculating a reactive power reference value according to the instantaneous reactive power of the inverter at the beginning of a regulation and the calculated reactive power change of the inverter;

[0060] Step S5: Calculate the voltage-reactive power droop coefficient according to the obtained reactive power reference value and the target voltage of the grid connection point, adjust the voltage-reactive power curve according to the new droop coefficient, and control the inverter to perform secondary regulation.

[0061] In this embodiment, in step S1, the grid connection point voltage at the current moment is assumed to be U, and the grid connection point target voltage is , the preset voltage threshold is ε1, the absolute value of the voltage difference |u|=|Uref-U|, compare |u| with ε1, and when the absolute value of the voltage difference |u| is greater than the preset voltage threshold ε1, the inverter is controlled to adjust. According to relevant standards, when When ε1 is 1.02pu, ε1 can be 0.005pu.

[0062] The target voltage at the grid connection point is It is known that during operation, the system always monitors the grid connection point voltage U and compares |u| with ε1.

[0063] In this embodiment, in step S2, the reactive power of the inverter at the current moment is compared with the absolute value of the reactive power difference between the reference reactive power of the primary regulating inverter and the preset reactive threshold. When the absolute value of the reactive difference is less than or equal to the preset reactive threshold, it indicates that the primary regulation is completed. The reference reactive power of the primary regulating inverter is obtained based on the preset grid-connected point target voltage and the current voltage-reactive curve.

[0064] In step S2, the reactive power of the inverter at a certain moment in the primary regulation process is assumed to be Q, and the reference reactive power of the primary regulation inverter is , the preset reactive power threshold is ε2, and the absolute value of reactive power difference DQ=|Q ref -Q|, compare DQ with ε2;

[0065] The signal when DQ≤ε2 is marked as ks_t=0, the signal when DQ>ε2 is marked as ks_t=1, and the signal at the previous moment is recorded as ks_t-1;

[0066] When ks_t-1=0, ks_t=1, the reactive power of the inverter at this time is recorded as the instantaneous reactive power Q1 of the inverter at the beginning of the primary regulation;

[0067] When ks_t-1=1 and ks_t=0, the reactive power of the inverter is measured as the instantaneous reactive power Q2 of the inverter when the primary regulation is completed. At this time, the voltage of the photovoltaic grid-connected point is measured as U min ;

[0068] The maximum voltage of the grid connection point in the ks_t=1 stage is Umax .

[0069] See also Figure 3 , during the primary regulation process, the inverter reactive power Q at the current moment is proportional to the reference reactive power of the primary regulation inverter When the absolute value of the difference in reactive power is less than or equal to the preset reactive threshold ε2 (the reactive power was adjusted before because the grid connection point voltage did not meet the requirements), it is considered that the reactive power has stabilized and one adjustment has been completed.

[0070] See also Figure 4 and Figure 5 During the primary regulation process, the instantaneous reactive power Q1 of the inverter at the beginning of the primary regulation, the instantaneous voltage Umin of the grid connection point when the primary regulation is completed, the instantaneous reactive power Q2 of the inverter when the primary regulation is completed, and the maximum voltage Umax of the grid connection point during the primary regulation stage are recorded. The reactive power of the inverter at a certain moment during the primary regulation process is Q. Vd is the d-axis voltage. Step S2 includes:

[0071] S21, detection Q and The value of , let DQ = |Q ref -Q|, by judging the size of the DQ value, the reactive power regulation state of the inverter is obtained, and the trigger signal is obtained according to the regulation state, thereby obtaining the logical relationship of the trigger signal; the signal at the previous moment is recorded as ks_t-1, and the next step of processing is performed by judging the logical relationship between ks_t and ks_t-1;

[0072] S22, after making corresponding judgment on the logical relationship, the change state of reactive power is obtained, and the reactive power output by the inverter before and after the state change, i.e., Q1, Q2, and the grid connection point voltage, i.e., U, are obtained according to the change state. min , U max .

[0073] Specifically, the inverter reactive power state adjustment process is: when DQ<ε2, it is considered that Q is When DQ>ε2, the inverter reactive power regulation is stable, and the signal at this time is recorded as ks_t=0; when DQ>ε2, it is considered that Q is equal to If they are not equal, adjust the inverter reactive power and record the signal at this time as ks_t=1. And record the signal at the previous moment as ks_t-1. ε2 is a specific value.

[0074] The logic relationship judgment process of the trigger signal is: when ks_t-1=0, ks_t=1, it is considered that the regulation state of the inverter reactive power has changed from stable regulation to starting regulation or being adjusted, and this state is recorded as state one; when ks_t-1=1, ks_t=0, it is considered that the regulation state of the inverter reactive power has changed from being adjusted to stable regulation, and this state is recorded as state two.

[0075] Obtaining the inverter reactive power and photovoltaic grid-connected point voltage data:

[0076] 1) When the inverter is in state 1, the reactive power of the inverter is recorded as Q1;

[0077] 2) When the inverter is in state 2, the inverter reactive power is recorded as Q2, and the photovoltaic grid voltage is recorded as U min ;

[0078] 3) When ks_t=1, the inverter is adjusting reactive power, and the maximum value of the photovoltaic grid-connected point voltage at this stage is recorded as U max .

[0079] In the subsequent steps, the obtained relevant data is used to perform calculations to obtain a new droop coefficient K of the voltage-reactive power control curve, and the droop coefficient K is updated to the voltage-reactive power control curve.

[0080] In step S2, when the reactive power regulation is stable (indicating that one-time regulation is completed), the comparison of |u| (the absolute value of the voltage difference between the grid connection point voltage at the current moment and the preset grid connection point target voltage) and ε1 (the preset voltage threshold) is also used to determine whether the instantaneous voltage of the grid connection point meets the requirements when one-time regulation is completed.

[0081] In step S2, the required parameters in the primary regulation process are recorded, including the instantaneous reactive power of the inverter at the beginning of the primary regulation, the instantaneous voltage of the grid connection point when the primary regulation is completed, the instantaneous reactive power of the inverter when the primary regulation is completed, and the maximum voltage of the grid connection point during the primary regulation stage.

[0082] See also Figure 6 In steps S3 to S5, the grid connection point voltage change is expressed as:

[0083]

[0084] The reactive power change of the photovoltaic inverter is expressed as:

[0085] .

[0086] Target grid connection point voltage ( )The calculation process of the required inverter reactive power output (Q3) is:

[0087] First, the change in inverter reactive power required to achieve the target voltage is calculated as:

[0088]

[0089] Secondly, the reactive power reference value is obtained according to the reactive power change of the inverter:

[0090]

[0091] Finally, the voltage-reactive power droop factor K is:

[0092] .

[0093] The calculated droop coefficient K is updated to the voltage-reactive power control to obtain a new voltage-reactive power curve. The inverter adjusts the reactive power according to this voltage-reactive power curve, and the grid connection point voltage can be adjusted to the grid connection point target voltage. nearby.

[0094] Through the above process, a voltage-reactive power curve suitable for the operation of this grid scenario can be obtained, which can better suppress the voltage limit at the grid connection point and improve the voltage support capacity of the photovoltaic inverter. It can be changed according to actual needs to regulate the voltage more flexibly.

[0095] The following simulation comparison is performed to illustrate the effect of the method of the embodiment of the present invention.

[0096] Assume that the relevant parameters of an existing distribution network are as follows:

[0097]

[0098] The distribution network is a 10-node radial distribution network with a voltage level of 10kv. A single photovoltaic unit is connected to 8 nodes, the photovoltaic access capacity is 1.05×0.73e6VA, and the total line load is 660+j155kVA. The inverter reactive control is turned on at 1.1 seconds of simulation, the grid load is reduced for the first time at 2.6 seconds, and the load is reduced for the second time at 3.2 seconds. Under this grid condition, the three control methods are simulated to compare the effect of grid overvoltage suppression. The results of the three control methods are shown in Figures 7 to 9 , Figures 7 to 9 In the figure, the horizontal axis is time (in seconds), the vertical axes P, Q, and U are active power, reactive power, and voltage, respectively, and pu represents the per-unit value.

[0099] The first control method is the traditional voltage-reactive power curve, the slope of the curve is fixed, and its control results can be found in Figure 7 In this control mode, the droop coefficient (curve slope) is set to k=10, the initial voltage is 1.055pu, the voltage is obviously over the limit, the inverter reactive power control is turned on at 1.1 seconds, the inverter absorbs reactive power, and the voltage is reduced to 1.042pu. At 2.6 seconds, the load is low and the voltage rises. According to the voltage-reactive power control, the inverter absorbs more reactive power to reduce the grid connection point voltage. Affected by the slope of the curve and the change of grid operation, the grid connection point voltage is not significantly reduced.

[0100] The second control method is to select the curve slope k according to the voltage. The control results are shown in Figure 8 The change formula of the curve slope k is expressed as:

[0101]

[0102] The initial voltage is 1.055pu, and the voltage is obviously over-limited. At 1.1 seconds, the inverter reactive control is turned on. When the voltage drops to 1.04pu, the droop coefficient changes, and the voltage stabilizes to 1.038pu. At 2.6 seconds, the grid operation changes, the load decreases, and the voltage increases. When it exceeds 1.04pu, the droop coefficient changes again, and the final voltage reaches 1.049pu. The voltage is still over-limited. In the case of many and fast changes in grid operation, using this method to adjust the droop coefficient is likely to cause frequent changes in the droop coefficient, resulting in voltage control oscillation.

[0103] The third control method is the adaptive droop coefficient voltage-reactive power control of the embodiment of the present invention. The control result is shown in FIG. Fig. 9 .

[0104] The initial voltage is 1.055pu, and the voltage is obviously over-limit. At 1.1 seconds, the inverter reactive control is turned on. Under the initial voltage-reactive control, the voltage is reduced to 1.038pu. The upper limit voltage of the adaptive droop coefficient is set to 1.02pu. Since the voltage is greater than 1.02pu after the initial (primary) adjustment of the voltage-reactive control, the adaptive control is enabled to change the voltage-reactive droop coefficient and perform secondary adjustment. The voltage after secondary adjustment is reduced to 1.02pu, and the voltage over-limit suppression effect is obvious. At 2.6 seconds, the grid operation changes, and the grid droop coefficient changes again according to the current voltage and grid operation conditions and the previous adjustment conditions. The voltage after the final adjustment is 1.028pu (subject to the limitation of the inverter reactive capacity, it is already the maximum reactive power output at this time). Compared with the first two existing methods, the adaptive droop coefficient voltage-reactive control method of the embodiment of the present invention has a more obvious voltage over-limit suppression effect.

[0105] The embodiment of the present invention also provides a voltage-reactive power adaptive optimization control system, which is used to implement the aforementioned voltage-reactive power adaptive optimization control method. The voltage-reactive power adaptive optimization control system includes:

[0106] The voltage acquisition module is used to obtain the grid connection point voltage in real time, including the instantaneous voltage of the grid connection point when the primary regulation is completed and the maximum voltage of the grid connection point during the regulation stage;

[0107] A threshold comparison module, used to compare the absolute value of the voltage difference between the grid connection point voltage at the current moment and the preset grid connection point target voltage with a preset threshold;

[0108] A reactive power acquisition module is used to acquire the instantaneous reactive power of the inverter when a regulation starts;

[0109] The voltage-reactive power curve module is used to obtain the reference reactive power of the inverter when the primary regulation is completed according to the preset grid connection point target voltage and voltage-reactive power curve;

[0110] A primary regulation module, used for controlling the inverter to perform primary regulation according to the reference reactive power of the inverter when the primary regulation is completed when the absolute value of the voltage difference is greater than a preset threshold value;

[0111] The reactive power variation calculation module is used to calculate the required inverter reactive power variation according to the instantaneous voltage at the grid connection point when the primary regulation is completed, the target voltage at the grid connection point, and the voltage variation and reactive power variation during the primary regulation process;

[0112] A reactive reference value calculation module is used to calculate a reactive reference value according to the instantaneous reactive power of the inverter at the beginning of a primary regulation and the calculated reactive power change of the inverter;

[0113] A voltage-reactive power droop coefficient updating module is used to calculate the voltage-reactive power droop coefficient according to the calculated reactive power reference value;

[0114] The secondary regulation module is used to adjust the voltage-reactive power curve according to the new droop coefficient and control the inverter to perform secondary regulation.

[0115] The embodiment of the present invention also provides a computer device, including a processor and a storage medium, wherein the storage medium stores a computer program, and when the computer program is executed by the processor, the aforementioned voltage-reactive power adaptive optimization control method is implemented.

[0116] The embodiment of the present invention also provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed, the aforementioned voltage-reactive power adaptive optimization control method is implemented.

[0117] The above is only a specific implementation of the invention, but the protection scope of the invention is not limited thereto. Those skilled in the art should understand that the invention includes but is not limited to the contents described in the above specific implementation. Any modification that does not deviate from the functional and structural principles of the invention will be included in the scope of the claims.

Claims

1. Voltage-reactive power adaptive optimization control method, characterized by: The voltage-reactive power adaptive optimization control method comprises: Step S1, obtaining the grid connection point voltage in real time, comparing the absolute value of the voltage difference between the current grid connection point voltage and the preset grid connection point target voltage with the preset voltage threshold, and controlling the inverter to perform an adjustment when the absolute value of the voltage difference is greater than the preset voltage threshold; Step S2, recording the instantaneous reactive power of the inverter at the beginning of the primary adjustment, the instantaneous voltage of the grid connection point when the primary adjustment is completed, the instantaneous reactive power of the inverter when the primary adjustment is completed, and the maximum voltage of the grid connection point during the primary adjustment stage, and judging whether the instantaneous voltage of the current grid connection point meets the requirements when the primary adjustment is completed, and performing secondary adjustment if it does not meet the requirements; Step S3, calculating the required inverter reactive power change according to the instantaneous voltage at the grid connection point when the primary adjustment is completed, the target voltage at the grid connection point, and the voltage change and reactive power change during the primary adjustment process; Step S4, calculating a reactive power reference value according to the instantaneous reactive power of the inverter at the beginning of a regulation and the calculated reactive power change of the inverter; Step S5: Calculate the voltage-reactive power droop coefficient according to the obtained reactive power reference value and the target voltage of the grid connection point, adjust the voltage-reactive power curve according to the new droop coefficient, and control the inverter to perform secondary regulation.

2. The voltage-reactive power adaptive optimization control method according to claim 1 is characterized in that: In step S1, the grid connection point voltage at the current moment is assumed to be U, and the grid connection point target voltage is , the preset voltage threshold is ε1, and the absolute value of the voltage difference |u|=|U ref -U|, compare |u| with ε1, and control the inverter to adjust when the absolute value of the voltage difference |u| is greater than the preset voltage threshold ε1; In step S2, the absolute value of the reactive difference between the inverter reactive power at the current moment and the reference reactive power of the primary regulating inverter is compared with the preset reactive threshold. When the absolute value of the reactive difference is less than or equal to the preset reactive threshold, it indicates that the primary regulation is completed. The reference reactive power of the primary regulating inverter is obtained based on the preset grid-connected point target voltage and the current voltage-reactive curve.

3. The voltage-reactive power adaptive optimization control method according to claim 2 is characterized in that: In step S2, the reactive power of the inverter at the current moment is assumed to be Q, and the reference reactive power of the inverter is adjusted to be , the preset reactive power threshold is ε2, and the absolute value of reactive power difference DQ=|Q ref -Q|, compare DQ with ε2; The signal when DQ≤ε2 is marked as ks_t=0, the signal when DQ>ε2 is marked as ks_t=1, and the signal at the previous moment is recorded as ks_t-1; When ks_t-1=0, ks_t=1, the reactive power of the inverter at this time is recorded as the instantaneous reactive power Q1 of the inverter at the beginning of the primary regulation; When ks_t-1=1 and ks_t=0, the reactive power of the inverter is measured as the instantaneous reactive power Q2 of the inverter when the primary regulation is completed. At this time, the voltage of the photovoltaic grid-connected point is measured as U min ; The maximum voltage of the grid connection point in the ks_t=1 stage is U max .

4. The voltage-reactive power adaptive optimization control method according to claim 2 is characterized in that: In step S2, the magnitude of |u| and ε1 is also compared to determine whether the instantaneous voltage at the grid connection point meets the requirement when one adjustment is completed.

5. The voltage-reactive power adaptive optimization control method according to claim 3 is characterized in that: In step S3, the target voltage of the grid connection point is reached Required inverter reactive power change The calculation formula is: 。 6. The voltage-reactive power adaptive optimization control method according to claim 5, characterized in that: In step S4, the reactive power reference value The calculation formula is: 。 7. The voltage-reactive power adaptive optimization control method according to claim 6, characterized in that: In step S5, the voltage-reactive power droop coefficient K The calculation formula is: 。 8. A voltage-reactive power adaptive optimization control system, used to implement the voltage-reactive power adaptive optimization control method according to any one of claims 1 to 7, characterized in that: The voltage-reactive power adaptive optimization control system comprises: The voltage acquisition module is used to obtain the grid connection point voltage in real time, including the instantaneous voltage of the grid connection point when the primary regulation is completed and the maximum voltage of the grid connection point during the regulation stage; A threshold comparison module, used to compare the absolute value of the voltage difference between the grid connection point voltage at the current moment and the preset grid connection point target voltage with a preset threshold; A reactive power acquisition module is used to acquire the instantaneous reactive power of the inverter when a regulation starts; The voltage-reactive power curve module is used to obtain the reference reactive power of the inverter when the primary regulation is completed according to the preset grid connection point target voltage and voltage-reactive power curve; A primary regulation module, used for controlling the inverter to perform primary regulation according to the reference reactive power of the inverter when the primary regulation is completed when the absolute value of the voltage difference is greater than a preset threshold value; The reactive power variation calculation module is used to calculate the required inverter reactive power variation according to the instantaneous voltage at the grid connection point when the primary regulation is completed, the target voltage at the grid connection point, and the voltage variation and reactive power variation during the primary regulation process; A reactive reference value calculation module is used to calculate a reactive reference value according to the instantaneous reactive power of the inverter at the beginning of a primary regulation and the calculated reactive power change of the inverter; A voltage-reactive power droop coefficient updating module is used to calculate the voltage-reactive power droop coefficient according to the calculated reactive power reference value; The secondary regulation module is used to adjust the voltage-reactive power curve according to the new droop coefficient and control the inverter to perform secondary regulation.

9. A computer device comprising a processor and a storage medium, wherein the storage medium stores a computer program, characterized in that: When the computer program is executed by a processor, the voltage-reactive power adaptive optimization control method described in any one of claims 1 to 7 is implemented.

10. A computer-readable storage medium, characterized in that: A computer program is stored thereon, and when the computer program is executed, the voltage-reactive power adaptive optimization control method described in any one of claims 1 to 7 is implemented.

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