Method for damping control of main power type doubly-fed wind farm based on multi-machine parameter adjustment

Abstract

The application provides a main power type doubly-fed wind farm damping control method based on multi-machine parameter adjustment, comprising the following steps: considering AC grid impedance, establishing an aggregated admittance model of the main power type doubly-fed wind farm; extracting a dominant instability mode of the wind farm station, determining an adjustment amplitude of the aggregated parameters by calculating sensitivity; considering multi-working condition operation, establishing a mapping relationship between short circuit ratio and working point and the parameter adjustment amplitude; according to SCADA real-time measurement data, online inversely distributing the parameter adjustment amplitude of each wind turbine generator, and improving system stability margin. The main power type doubly-fed wind farm damping control method provided by the application can effectively avoid invalid parameter adjustment based on quantitative characterization of key parameter sensitivity; the formed multi-working condition mapping relationship can reflect the influence of real-time state change of the system on parameter damping, and is convenient for online application.

Description

Technical Field

[0001] This invention relates to the field of damping stability control technology for main-power type doubly-fed wind farms, specifically to a damping control method, system, terminal, and medium for main-power type doubly-fed wind farms based on multi-machine parameter adjustment. Background Technology

[0002] In the context of a "dual-high" power system characterized by a high proportion of renewable energy and a high proportion of power electronic equipment, the proportion of synchronous generators, which traditionally support the stable operation of the power system, is gradually decreasing. This necessitates renewable energy power plants to assume the responsibility of maintaining basic grid operating parameters (such as frequency and inertia). However, renewable energy power plants that previously relied on grid-connected control (such as phase-locked loop control) find it difficult to achieve this goal. Wind farms, which utilize voltage source control as their main power source, possess active response and self-organizing grid operation capabilities, making them one of the key technologies for the power supply side in constructing a "dual-high" power system.

[0003] However, due to the multi-bandwidth coupling effect of voltage source control, main-power wind farms are highly susceptible to oscillation risks over a wide frequency range. For example, virtual / inertial synchronization loops can easily induce sub- / super-synchronous frequency band oscillations, and the coupling effect of virtual admittance control and current loops can easily induce mid-to-high frequency oscillations. Identifying the key parameters causing oscillation instability in main-power wind farms and designing damped stability control strategies that can adapt to various operating conditions is crucial for ensuring their safe and stable operation. In recent years, domestic and international research on stability control has mainly focused on grid-connected wind farms, with less consideration given to the emerging main-power wind farm category. Therefore, it is necessary to conduct relevant research in this area. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the purpose of this invention is to provide a damping control method and system for a main power source type doubly fed wind farm based on multi-machine parameter adjustment.

[0005] According to a first aspect of the present invention, a damping control method for a doubly fed wind farm based on multi-machine parameter adjustment is provided, comprising:

[0006] Establish a single-unit aggregation model for a doubly-fed wind farm with a main power source, and derive its AC admittance model Y. WF (s), forming a closed-loop model Y considering the internal impedance of the power grid. sys (s);

[0007] Based on the closed-loop model Y sys (s) Extract the dominant instability mode of the main power source type doubly fed wind farm, calculate the sensitivity information of key parameters in the aggregate parameters, and determine the adjustment range of the aggregate parameters;

[0008] Considering the full-condition operation of the main power source type doubly fed wind farm and the changes in grid intensity, a mapping relationship P between the operating point, short-circuit ratio and the adjustment range of the aggregation parameter is established;

[0009] Based on the site status measurement data and the mapping relationship P, the adjustment range of the aggregated parameters is given online, and the adjustment range of the aggregated parameters of each wind turbine in the main power source type doubly fed wind farm is distributed in reverse according to the active power output of the wind turbine, thereby improving the stability margin of the main power source type doubly fed wind farm.

[0010] Preferably, the main power supply type doubly fed wind farm includes a main circuit and a control circuit, wherein the main circuit includes a front-end wind turbine aerodynamic part, a two-mass block equivalent transmission chain, a doubly fed induction motor, a turbine-side converter, a grid-side converter, a DC-side capacitor, an AC-side filter, and a transformer connected in sequence.

[0011] The control circuit includes a machine-side control circuit and a grid-side control circuit. The machine-side control circuit includes an inner current loop connected to the machine-side converter. One side of the inner current loop is connected in series with a reactive power-voltage droop loop and a virtual admittance, and the other side is connected in series with a virtual synchronization loop and a maximum power tracking loop. The grid-side control circuit includes an inner current loop. One side of the inner current loop is connected to a phase-locked loop, and the other side is connected in series with a reactive power outer loop and a DC voltage outer loop.

[0012] Preferably, the main circuit includes two busbars, each busbar containing two feeders, and each feeder is connected to two doubly fed induction motors.

[0013] Preferably, the establishment of a single-unit aggregation model for a main power source type doubly-fed wind farm and the derivation of its AC admittance model Y WF (s), forming a closed-loop model Y considering the internal impedance of the power grid. sys (s), including:

[0014] Based on the principle of capacity equivalence, the electrical and control aggregation parameters of the main power supply type doubly-fed wind farm generator units are calculated. Small-signal models of each component in the main circuit are established. After eliminating the intermediate variables of the small-signal models, the input-output relationship of AC voltage and current on the grid-connected side is extracted, and a single-unit aggregation model Y of the main power supply type doubly-fed wind farm is established. WT (s), in the form of:

[0015]

[0016] In the formula, Δi d (s), Δi q (s) represents the small-signal AC current components along the d-axis and q-axis, Δu d (s), Δu q (s) represents the small-signal AC voltage components of the d-axis and q-axis; Ydd (s), Y dq (s), Y qd (s), Y qq (s) represent the admittances of the dd, dq, qd, and qq channels, respectively;

[0017] The equivalent pooling impedance Y of the power collection network of the power station is calculated based on the principle of energy conservation. Line (s), through circuit calculations, an AC admittance model Y of the main power supply type doubly fed wind farm is formed. WF (s), in the form of:

[0018]

[0019] In the formula, Y 11 (s), Y 12 (s), Y 21 (s) and Y 22 (s) is Y WF The matrix elements of (s);

[0020] Considering the Thevenin equivalent impedance of the power grid as Y Grid (s), a closed-loop analysis model for the main power source type doubly fed wind farm is established as Y SYS (s), in the form of:

[0021] Y sys (s)=Y WF (s)+Y Grid (s).

[0022] Preferably, the closed-loop model Y is used as the basis for... sys (s) Extract the dominant instability mode of the main power source type doubly-fed wind farm, calculate the sensitivity information of key parameters in the aggregated parameters, and determine the adjustment range of the aggregated parameters, including:

[0023] Calculate the closed-loop model Y sys The determinant of (s) is given, and its zero-point distribution is described. The weakly damped mode, i.e., the real part mode at the zero point, is extracted as the dominant instability mode of the system. m :

[0024] det[Y sys [(s)]=0

[0025] →Zero-point distribution: {s1,s2,...,s} n}

[0026] → Dominant instability mode: min{|Re(s) m )|}

[0027] Substituting the determined dominant instability mode into the closed-loop model Y sys (s) and perform eigenvalue decomposition:

[0028]

[0029] In the formula, r1 and r2 are the right column eigenvectors, l1 and l2 are the left row eigenvectors, and λ1 and λ2 are the modal admittances of the system, with one term being 0, i.e., the weakest modal admittance;

[0030] Setting λ2 = 0, the weakest mode admittance is extracted. Considering the key parameters of the main power source type doubly-fed wind farm, including the virtual synchronous damping coefficient D and the reactive power-voltage droop coefficient K, the sensitivity sen(s) of the key parameters is calculated based on the derivative chain rule. m ,ρ k ):

[0031]

[0032] In the formula, PF 11 PF 12 PF 21 and PF 22 ρ represents the participation factor of each matrix element in the dominant instability mode. k This represents the key parameters being considered;

[0033] The sensitivity of the key parameters is normalized, and considering the effective characterization range ξ of the first-order perturbation, the adjustment range η(s) of the key parameters is set. i ,ρ k ):

[0034]

[0035] In the formula, This represents the normalized parameter sensitivity.

[0036] Preferably, the step of establishing a mapping relationship P between the operating point, short-circuit ratio, and the adjustment range of the aggregation parameter, considering the full-condition operation of the main power source-type doubly-fed wind farm and changes in grid intensity, includes:

[0037] The main power source type wind turbine unit operates under all operating conditions, with the active power output value ranged from 10% to 100% at the operating point, and the power factor of the reactive power output set to 1;

[0038] The short-circuit ratio is set to a range of 1.2 to 6.

[0039] Based on different combinations of active / reactive power operating states and short-circuit ratios, the corresponding adjustment ranges of key parameters are obtained, forming a mapping relationship P:

[0040]

[0041] In the formula, P1, Q1, SCR1, ..., Pn Q n SCR n Y represents the different combinations of active power, reactive power, and short-circuit ratios considered. sysi (s) represents the system frequency domain admittance matrix corresponding to the i-th operating condition combination, s i Represents the corresponding dominant instability mode, ρ k This represents the key parameters being considered.

[0042] Preferably, the step of giving the adjustment range of the aggregation parameter online based on the station status measurement data and the mapping relationship P includes:

[0043] Considering the station condition measurement data as {P m Q m SCR m}, through aggregation parameter ρ k Adjustment range η m (ρ k The parameter adjustment range for each wind turbine is as follows:

[0044]

[0045] In the formula, P WTl The active power output level of the l-th wind turbine is obtained from the monitoring system.

[0046] According to a second aspect of the present invention, a main power supply-type doubly fed wind farm damping control system based on multi-machine parameter adjustment is provided, comprising:

[0047] The modeling module establishes a single-unit aggregated model of the main power source type doubly-fed wind farm and derives its AC admittance model Y. WF (s), forming a closed-loop model Y considering the internal impedance of the power grid. sys (s);

[0048] Adjustment amplitude shaping module, this module is based on the closed-loop model Y sys (s) Extract the dominant instability mode of the main power source type doubly fed wind farm, calculate the sensitivity information of key parameters in the aggregate parameters, and determine the adjustment range of the aggregate parameters;

[0049] The mapping module considers the full-condition operation of the main power source type doubly fed wind farm and the changes in grid intensity, and establishes a mapping relationship P between the operating point, short-circuit ratio and the adjustment range of the aggregation parameter;

[0050] The adjustment range quantitative module, based on the station status measurement data and the mapping relationship P, gives the adjustment range of the aggregated parameters online, and distributes the parameter adjustment range of each wind turbine in the main power source type doubly fed wind farm in reverse according to the active power output of the wind turbine, thereby improving the stability margin of the main power source type doubly fed wind farm.

[0051] According to a third aspect of the present invention, a terminal is provided, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, it can be used to execute the aforementioned mains power type doubly fed wind farm damping control method based on multi-machine parameter adjustment, or to run the aforementioned mains power type doubly fed wind farm damping control system based on multi-machine parameter adjustment.

[0052] According to a fourth aspect of the present invention, a computer-readable storage medium is provided having a computer program stored thereon, which, when executed by a processor, can be used to perform the aforementioned mains power type doubly fed wind farm damping control method based on multi-machine parameter adjustment, or to run the aforementioned mains power type doubly fed wind farm damping control system based on multi-machine parameter adjustment.

[0053] Compared with the prior art, the embodiments of the present invention have at least one of the following beneficial effects:

[0054] The damping control method and system for a doubly fed wind farm based on multi-machine parameter adjustment in this invention embodiment can effectively avoid ineffective parameter adjustment and reduce the cost of parameter adjustment by quantitatively characterizing the sensitivity of key parameters.

[0055] The damping control method and system for a doubly fed wind farm based on multi-machine parameter adjustment in this invention can reflect the impact of real-time system state changes on parameter stabilization through the multi-condition mapping relationship formed, which is convenient for online application. Attached Figure Description

[0056] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0057] Figure 1 This is a flowchart of a main power supply-type doubly fed wind farm damping control method based on multi-machine parameter adjustment in one embodiment of the present invention;

[0058] Figure 2 This is a schematic diagram of the main circuit and control circuit of a voltage source type doubly fed wind turbine generator according to an embodiment of the present invention;

[0059] Figure 3 This is a schematic diagram of the main circuit of a doubly fed wind farm with a main power source in a preferred embodiment of the present invention;

[0060] Figure 4 This is a frequency sweep verification diagram of the aggregated admittance of a single unit in a main power supply type doubly fed wind farm in a preferred embodiment of the present invention.

[0061] Figure 5This is a schematic diagram of the dominant instability mode and its corresponding key parameter sensitivity in a preferred embodiment of the invention, where a is a schematic diagram of the dominant instability mode; b is a schematic diagram of the key parameter sensitivity.

[0062] Figure 6 This is a time-domain simulation test diagram of the damping control method for a doubly fed wind farm based on multi-machine parameter adjustment in one application embodiment of the present invention; where a is the effect diagram of adjusting the virtual damping coefficient; b is the effect diagram of adjusting the reactive power droop coefficient. Detailed Implementation

[0063] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention. These all fall within the scope of protection of the present invention.

[0064] This invention is mainly based on the quantitative characterization of the dominant instability modes and parameter sensitivity of the main power source type wind farm. It further considers the different active / reactive power output states of each wind turbine unit within the farm and the strength changes of the power grid, and establishes a mapping relationship between the adjustment range of key parameters and the system operating status. Based on this mapping relationship, combined with the real-time measurement data of the farm system, the parameter adjustment commands of each voltage source type wind turbine unit are distributed online in reverse, thereby improving the overall stability margin of the farm.

[0065] Based on the above inventive concept, the present invention provides an embodiment, see below. Figure 1 A damping control method for a doubly fed wind farm with a main power source based on multi-machine parameter adjustment is described below.

[0066] S1. Establish a single-unit aggregation model for the main power source type doubly-fed wind farm and derive its AC admittance model Y. WF (s), forming a closed-loop model Y considering the internal impedance of the power grid. sys (s);

[0067] S2, the closed-loop model Y obtained based on S1 sys (s) Extract the dominant instability mode of the main power source type doubly fed wind farm, calculate the sensitivity information of key parameters in the aggregate parameters, and determine the adjustment range of the aggregate parameters;

[0068] S3, considering the full-condition operation of the main power source type doubly fed wind farm and the changes in grid intensity, establish the mapping relationship P between the operating point, short-circuit ratio and the adjustment range of the aggregate parameters obtained in S2;

[0069] S4, based on the mapping relationship P between the station status measurement data and S3, provides the adjustment range of the aggregated parameters online, and distributes the parameter adjustment range of each wind turbine in the main power source type doubly fed wind farm in reverse according to the active power output of the wind turbine, thereby improving the stability margin of the main power source type doubly fed wind farm.

[0070] This embodiment can distribute parameter adjustment commands for each voltage source type wind turbine in reverse online based on real-time measurement data of the station system, thereby improving the overall stability margin of the station.

[0071] In a preferred embodiment of the present invention, a main power source type doubly-fed wind farm is provided, comprising voltage source type doubly-fed wind turbine generators, wherein the generator-side converter adopts virtual synchronization control (voltage source control), including virtual synchronization loop, maximum power point tracking control, reactive power-voltage droop control, virtual admittance, and current inner loop; the grid-side converter adopts constant DC voltage control (current source control), including phase-locked loop, reactive power outer loop, DC voltage outer loop, and current inner loop. The power collection network of the wind farm, i.e., the overhead lines connecting the wind farm to each wind turbine generator, includes the wind turbine generator output transformer, land cable, overhead line, and the wind farm step-up transformer.

[0072] In a preferred embodiment of the present invention, S1 is implemented as follows:

[0073] S11. Based on the principle of capacity equivalence, calculate the electrical and control aggregation parameters of the voltage source type doubly-fed induction generator (DFIG) wind turbine. Establish small-signal models of its front-end aerodynamic components, drive train, DFIG induction motor, turbine-side converter, grid-side converter, and DC capacitor. After eliminating intermediate variables, extract the input-output relationship between the grid-connected AC voltage and current to establish the AC admittance aggregation model of the voltage source type DFIG wind turbine (considering a certain operating state, such as active / reactive power output of P). m and Q m The specific format is as follows:

[0074]

[0075] In the formula, Δi d (s), Δi q (s) represents the small-signal AC current components along the d-axis and q-axis, Δu d (s(、Δu q (s) represents the small-signal AC voltage components along the d-axis and q-axis. dd (s), Y dq (s), Y qd (s), Y qq (s) represent the admittances of the dd, dq, qd, and qq channels, respectively.

[0076] S12, simultaneously, the equivalent pooling impedance Y of the power collection network of the station is calculated based on the principle of energy conservation. Line (s), through circuit calculations, the AC aggregate admittance Y of the main power supply type doubly fed wind farm is formed. WF (s), specifically as follows:

[0077]

[0078] In the formula, Y 11 (s), Y 12 (s), Y 21 (s) and Y 22 (s) is Y WF The matrix elements of (s).

[0079] S13, considering the Thevenin equivalent impedance of the power grid as Y Grid (s), a closed-loop analysis model of the system can be established as Y SYS (s), specifically as follows:

[0080] Y sys (s)=Y WF (s)+Y Grid (s) (3)

[0081] In a preferred embodiment of the present invention, S2 is implemented as follows:

[0082] S21, Calculate the closed-loop model Y obtained above. sys The determinant of (s) is given, and its zero-point distribution is described. The weakly damped (real part of zero) mode is extracted as the dominant instability mode of the system. Specifically:

[0083]

[0084] S22, the determined dominant instability mode (in s m (For example) Substitute Y sys (s) and perform feature decomposition, as follows:

[0085]

[0086] In the formula, r1 and r2 are the right column eigenvectors, l1 and l2 are the left row eigenvectors, and λ1 and λ2 are the modal admittances of the system, with one term being 0 (called the weakest modal admittance).

[0087] S23, extract the weakest mode admittance (taking λ2=0 as an example), consider the key controllable parameters of the main power source type wind farm, such as the virtual synchronous damping coefficient D, reactive power-voltage droop coefficient K, etc., and calculate the sensitivity sen(s) of the key parameters based on the derivative chain rule. m ,ρ k The details are as follows:

[0088]

[0089] In the formula, PF 11 PF 12 PF 21 and PF 22 ρ represents the participation factor of each matrix element in the dominant instability mode. k This represents the key parameters being considered.

[0090] S24, normalize the sensitivity of the parameters obtained above, and considering the effective characterization range ξ of the first-order perturbation (e.g., 15%), set the adjustment range η(s) of the parameters. i ,ρ k The details are as follows:

[0091]

[0092] In the formula, This represents the normalized parameter sensitivity.

[0093] In a preferred embodiment of the present invention, S3 is implemented as follows:

[0094] S31, considering the full-condition operation of the main power source type wind turbine, sets the typical value range of active power output to 10% to 100%, and the reactive power output mainly considers the case where the power factor is 1.

[0095] S32, taking into account the changes in power grid strength, sets the typical range of short-circuit ratio to 1.2 to 6.

[0096] S33, based on different combinations of active / reactive power operating states and short-circuit ratios, repeats steps S1 and S2 to obtain the corresponding key parameter adjustment ranges, thereby forming a mapping relationship P. Specifically:

[0097]

[0098] The multi-condition mapping relationship formed in this embodiment can reflect the impact of real-time system state changes on parameter stabilization, which is convenient for online application.

[0099] In a preferred embodiment of the present invention, S4 is implemented as follows:

[0100] S41, based on the above mapping relationship P, and the SCADA measurement data of the main power source type doubly fed wind farm, including the grid impedance, the active / reactive power output of each wind turbine and station, etc., the aggregation parameter adjustment range is given online.

[0101] S42, based on the active power output of each wind turbine, reversely allocates the adjustment range of key parameters.

[0102] Specifically, considering the station's operating status as {P} m Q m SCR m}, with aggregation parameter ρ k Adjustment range η m (ρ k For example, the parameter adjustment range for each wind turbine can be obtained as follows:

[0103]

[0104] In the formula, P WTl The active power output level of the l-th wind turbine can be obtained from the SCADA monitoring system.

[0105] Through the above embodiments, the parameter adjustment commands of each voltage source type wind turbine can be distributed online in reverse by combining the real-time measurement data of the station system, thereby improving the overall station stability margin.

[0106] Based on the same inventive concept, in other embodiments of the present invention, a main power supply-type doubly fed wind farm damping control system based on multi-machine parameter adjustment is provided, comprising:

[0107] The modeling module establishes a single-unit aggregated model of the main power source type doubly-fed wind farm and derives its AC admittance model Y. WF (s), forming a closed-loop model Y considering the internal impedance of the power grid. sys (s);

[0108] Adjustment amplitude shaping module, this module is based on closed-loop model Y sys (s) Extract the dominant instability mode of the main power source type doubly fed wind farm, calculate the sensitivity information of key parameters in the aggregate parameters, and determine the adjustment range of the aggregate parameters;

[0109] The mapping module considers the full-condition operation of the main power source type doubly fed wind farm and the changes in grid intensity, and establishes a mapping relationship P between the operating point, short-circuit ratio and the adjustment range of aggregation parameters;

[0110] The adjustment range quantitative module, based on the station status measurement data and mapping relationship P, gives the adjustment range of the aggregated parameters online. It then distributes the parameter adjustment range of each wind turbine in the main power source type doubly-fed wind farm in reverse according to the active power output of the wind turbine, thereby improving the stability margin of the main power source type doubly-fed wind farm.

[0111] The specific implementation techniques of each module / unit in the above examples of the present invention can be referred to the steps of the main power supply type doubly fed wind farm damping control method based on multi-machine parameter adjustment in the above embodiments, and will not be repeated here.

[0112] Based on the same inventive concept, in other embodiments of the present invention, a terminal is provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, it can be used to execute the method described therein, or to run the system described therein.

[0113] Based on the same inventive concept, in other embodiments of the present invention, a computer-readable storage medium is provided having a computer program stored thereon, which, when executed by a processor, can be used to perform the method described thereon, or to run the system described thereon.

[0114] To further understand the technical solutions of the embodiments of the present invention, and to verify the technical effects of the technical solutions in the above embodiments, the present invention provides a specific application embodiment.

[0115] Please see Figure 2 In this embodiment, the voltage-source doubly-fed induction generator (DFIG) is used with a power rating of 1.5MW. The main circuit includes the front-end wind turbine aerodynamic components, a two-mass equivalent transmission chain, a DFIG induction motor, a turbine-side converter, a grid-side converter, a DC-side capacitor (25mF), an AC-side filter (resistance 0.27μΩ, inductance 0.4μH), and a 0.69 / 35kV transformer. Thyristor-side control includes reactive power-voltage droop (droop coefficient 0.002pu), virtual admittance (virtual resistance 0.2pu, virtual inductance 0.2pu), a current inner loop (bandwidth 200Hz), maximum power point tracking control, and virtual synchronization control (virtual inertia coefficient 2p.u., damping coefficient 40p.u.). The controller delay is 100ms. The grid-side control includes a DC voltage outer loop (10Hz bandwidth), a reactive power outer loop (8Hz bandwidth), a current inner loop (200Hz bandwidth), and a phase-locked loop synchronous control (40Hz bandwidth). The controller delay is 100ms.

[0116] Please see Figure 3 In this embodiment, the main power source type doubly-fed wind farm case has two buses, each containing two feeders, and each feeder connects to two 1.5MW voltage source type doubly-fed wind turbine units. It is connected to the AC grid via a step-up transformer at the site, and the AC grid is characterized using the Thevenin equivalent circuit. The AC transmission line resistance is 0.011Ω / km, and the inductance is 0.94mH / km. The entire site contains 11 nodes.

[0117] Please see Figure 4 In this embodiment, the established doubly-fed wind farm single-unit aggregated admittance model was verified. The four sub-figures, from left to right and top to bottom, represent the aggregated impedance amplitudes of the dd, dq, qd, and qq channels, respectively. It can be clearly seen that the measured data with black scattered dots are in good agreement with the theoretical modeling data.

[0118] Please see Figure 5 In Figure a, in this embodiment, the dominant instability mode is determined to be 0.155±j49.9, which is a negative damping instability mode, corresponding to an oscillation frequency of 7.94Hz. Please refer to [link / reference]. Figure 5 Figure b shows the sensitivity indices of key controllable parameters for this dominant instability mode, presented as a histogram and normalized. It can be seen that the virtual damping coefficient D and the reactive power droop coefficient K have the highest sensitivity values ​​and the greatest impact on system instability. Setting the upper limit of parameter adjustment amplitude to 15%, the adjustment amplitude of the aggregate parameter can be determined according to equation (9), where D is 5.7% and K is 2.55%.

[0119] Please see Figure 6 Figure a shows the time-domain simulation results of oscillation suppression for the main power source wind farm based on multi-machine parameter adjustment in this embodiment. The SCADA system detected divergent oscillations in the current at nodes 2, 4, 7, and 9 of the main power source wind farm, and both active and reactive power at the grid connection point of the power station exhibited divergent oscillations. Based on the determined aggregation parameter adjustment range, such as D being 5.7%, the adjustment range of the damping coefficient of each wind turbine was allocated online in reverse, and the action was taken at 0.666s to suppress the oscillations. The current and power at each node then entered a stable state. Please refer to [link to relevant documentation]. Figure 6 Figure b. Similarly, based on the adjustment range of the reactive power droop aggregation parameter K determined above (2.55%), the adjustment range of the droop coefficient of each wind turbine is also distributed online in reverse. The action is taken at 0.666s to suppress the oscillation, and the current and power of each node enter a stable state.

[0120] Therefore, the method of the present invention, by proposing a damping control method for a main power source type doubly fed wind farm based on multi-machine parameter adjustment, can effectively suppress the instability of the station and is easy to apply online.

[0121] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various modifications or variations within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A main power supply type doubly-fed wind farm damping control method based on multi-machine parameter adjustment, characterized in that, Comprise: A single-machine aggregated model of a doubly-fed wind farm with main power supply is established, and its AC admittance model Y WF (s) is derived sys (s) is formed, which is a closed-loop model considering the grid impedance based on the closed loop model Y sys (s) extracting the dominant instability mode of the main power supply type doubly-fed wind farm, calculating the sensitivity information of the key parameters in the aggregated parameters, and determining the adjustment range of the aggregated parameters; Considering the full operating condition of the main power source type doubly-fed wind farm and the grid strength change, a mapping relationship P of the operating working point, short circuit ratio and the aggregated parameter adjustment amplitude is established; Based on the field station state measurement data and the mapping relationship P, the adjustment amplitude of the aggregated parameter is given online, the aggregated parameter adjustment amplitude of each wind turbine in the main power source type doubly-fed wind farm is inversely distributed according to the active power output of the wind turbine, and the stability margin of the main power source type doubly-fed wind farm is improved; The single-machine aggregated model of the main-force power supply type doubly-fed wind farm is established, and an AC admittance model Y WF (s) is derived, forming a closed-loop model Y sys (s) considering the impedance of the power grid Based on the principle of capacity equivalence, the electrical and control aggregation parameters of the main power type doubly-fed wind farm generator set are calculated, a small signal model of each element in the main circuit is established, the intermediate variables of the small signal model are eliminated, the input and output relationship of the grid-side AC voltage and current is extracted, and a single-machine aggregation model Y of the main power type doubly-fed wind farm is established WT (s) in the form of: where Δi d (s) represents the d-axis and q-axis small-signal ac current components, Δu q (s) represents the d-axis and q-axis small-signal ac voltage components; Y d (s) represents the d-axis and q-axis small-signal ac voltage components; Y q (s) represents the d-axis and q-axis small-signal ac voltage components; Y dd (s) represents the d-axis and q-axis small-signal ac voltage components; Y dq (s) represents the d-axis and q-axis small-signal ac voltage components; Y qd (s) represents the d-axis and q-axis small-signal ac voltage components; Y qq (s) represents the dd, dq, qd, and qq channel admittances, respectively; Based on the principle of energy conservation to calculate the equivalent aggregate impedance Y of the field station power collection network Line (s), the AC admittance model Y of the main power type doubly-fed wind farm is formed by circuit operation WF (s), in the form of: where Y 11 (s), Y 12 (s), Y 21 (s), and Y 22 (s) is Y WF (s) is the matrix element of Y Consider the Thevenin equivalent impedance of the grid as Y Grid (s), the closed-loop analysis model of the main power supply type doubly-fed wind farm is established as Y SYS (s), which is in the form of Y sys (s) = Y WF (s) + Y Grid (s) (3).

2. The method according to claim 1, wherein the method is characterized by, The main power source type doubly-fed wind farm comprises a main circuit and a control circuit, wherein the main circuit comprises, in sequence, a front-end wind turbine aerodynamic part, two mass block equivalent transmission chains, a doubly-fed induction motor, a machine-side converter, a grid-side converter, a DC side capacitor, an AC side filter and a transformer; The control circuit comprises a machine-side control circuit and a grid-side control circuit, the machine-side control circuit comprises a current inner loop connected with the machine-side converter, one side of the current inner loop is connected with a reactive power-voltage droop loop and a virtual admittance in series, and the other side is connected with a virtual synchronization loop and a maximum power tracking loop in series; the grid-side control circuit comprises a current inner loop, one side of the current inner loop is connected with a phase-locked loop, and the other side is connected with a reactive power outer loop and a DC voltage outer loop in series.

3. The method according to claim 2, wherein the method is characterized by, The main circuit comprises two busbars, each of the busbars comprises two feeder lines, and each of the feeder lines is connected with two doubly-fed induction motors.

4. The method of claim 1, wherein the method is characterized by, The closed-loop model Y sys (s) extracting the dominant instability mode of the main power supply type doubly-fed wind farm, calculating the sensitivity information of the key parameters in the aggregated parameters, and determining the adjustment range of the aggregated parameters, comprising: Compute the closed loop model Y sys (s) and give its zero distribution, extract weakly damped, i.e. real part of zeros, as dominant instability mode s m : det[Y sys (s)] = 0 → zero point distribution: {s1, s2,..., s n} Dominant instability mode: min{|Re(s m )|} (4) Substitute the determined dominant instability mode into the closed-loop model Y sys (s) and perform eigen decomposition: In the formula, r1 and r2 are right column eigenvectors, l1 and l2 are left row eigenvectors, λ1 and λ2 are modal admittances of the system, and one item is 0, that is, the weakest modal admittance; Setting λ2=0, extracting the weakest modal admittance, considering the key parameters of the main power type doubly-fed wind farm, including virtual synchronous damping coefficient D, reactive power-voltage droop coefficient K, calculating the sensitivity of the key parameters sen(s m , ρ k ): where PF 11 , PF 12 , PF 21 , and PF 22 are the participation factors of each matrix element to the dominant instability mode, and p k represents the key parameter under consideration; The sensitivity of the key parameter is normalized and the effective range of the first order perturbation ξ is considered, and the adjustment range η(s i ,ρ k ) of the key parameter is set: In the formula, represents the normalized parameter sensitivity.

5. The method of claim 1, wherein the method is a multi-machine parameter adjustment based main power source type DFIG wind farm damping control method. The consideration of the full operating condition of the main power source type doubly-fed wind farm and the grid strength change, and the establishment of the mapping relationship P of the operating working point, short circuit ratio and the aggregated parameter adjustment amplitude, comprise: The full operating condition of the main power source type wind turbine, the value range of the active power output of the set operating working point is 10% to 100%, and the power factor of the reactive power output is 1; According to the grid strength change, the value range of the short circuit ratio is set to 1.2 to 6; Based on different combinations of active / reactive operating states and short circuit ratios, the corresponding key parameter adjustment amplitude is obtained, and the mapping relationship P is formed: where P1, Q1, SCR1,..., P n , Q n , SCR n represent the different active, reactive and short circuit ratio combinations under consideration, Y sysi (s) represents the system frequency domain admittance matrix corresponding to the i-th operating point combination, s i represents the corresponding dominant instability mode, p k represents the key parameter under consideration.

6. The method of claim 1, wherein the method is a multi-machine parameter adjustment based main power source type DFIG wind farm damping control method. The online given adjustment amplitude of the aggregated parameter based on the field station state measurement data and the mapping relationship P, comprises: Consider the station state measurement data as {P m , Q m , SCR m}, by adjusting the range of the aggregation parameter ρ k η m (ρ k ), the parameter adjustment range of each wind turbine is: where P WTl represents the active power level of the first wind turbine, which is obtained by the monitoring system.

7. A multi-machine parameter adjusted main power source type doubly-fed wind farm damping control system for implementing the multi-machine parameter adjusted main power source type doubly-fed wind farm damping control method according to any one of claims 1-6, characterized in that, Comprise: a modeling module that establishes a single-machine aggregated model of the main power supply type doubly-fed wind farm, deriving its AC admittance model Y WF (s) forming a closed-loop model Y sys (s) taking into account the grid impedance an adjustment amplitude shaping module that shapes the adjustment amplitude based on the closed loop model Y sys (s) extracting the dominant instability mode of the main power supply type doubly-fed wind farm, calculating the sensitivity information of the key parameters in the aggregated parameters, and determining the adjustment amplitude of the aggregated parameters; A mapping module, which considers the full operating condition of the main power source type doubly-fed wind farm and the grid strength change, and establishes the mapping relationship P of the operating working point, short circuit ratio and the aggregated parameter adjustment amplitude; An adjustment amplitude quantitative module, which gives the adjustment amplitude of the aggregated parameter online based on the field station state measurement data and the mapping relationship P, and inversely distributes the parameter adjustment amplitude of each wind turbine in the main power source type doubly-fed wind farm according to the active power output of the wind turbine, so as to improve the stability margin of the main power source type doubly-fed wind farm.

8. A terminal comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, The processor executes the program and can be used to execute the main power source type doubly-fed wind farm damping control method based on multi-machine parameter adjustment in any one of claims 1 to 6, or run the main power source type doubly-fed wind farm damping control system based on multi-machine parameter adjustment in claim 7.

9. A computer-readable storage medium having stored thereon a computer program, characterized in that, The program can be executed by the processor to execute the multi-machine parameter adjustment-based main power source type doubly-fed wind farm damping control method of any one of claims 1-6, or run the multi-machine parameter adjustment-based main power source type doubly-fed wind farm damping control system of claim 7.

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