CN118040767A

CN118040767A - Grouping method, device, equipment and storage medium for new energy station

Info

Publication number: CN118040767A
Application number: CN202410032915.4A
Authority: CN
Inventors: 周鑫; 朱益华; 张丽; 罗超; 姜訸; 涂亮; 何鑫; 余佳微; 刘宇嫣; 曾冠铭
Original assignee: CSG Electric Power Research Institute; Electric Power Research Institute of Yunnan Power Grid Co Ltd
Current assignee: CSG Electric Power Research Institute; Electric Power Research Institute of Yunnan Power Grid Co Ltd
Priority date: 2024-01-09
Filing date: 2024-01-09
Publication date: 2024-05-14

Abstract

The embodiment of the application discloses a grouping method, a grouping device, grouping equipment and a storage medium of a new energy station, wherein the method comprises the following steps: collecting wind speed data of each wind turbine in the new energy station; dividing wind speed data of each model wind turbine generator set by using a starting point and an ending point of an MPPT region of each model wind turbine generator set to obtain wind turbine generator sets in different wind speed regions; dividing all wind turbines in each wind speed interval of each model into a grouping group to obtain a grouping result of the new energy station. The grouping result obtained by the method has higher equivalent precision and stronger wind speed scene adaptability, and has higher engineering practicability.

Description

Grouping method, device, equipment and storage medium for new energy station

Technical Field

The present application relates to the field of power systems, and in particular, to a method, an apparatus, a device, and a storage medium for grouping new energy stations.

Background

With the proposal of the 'double carbon' strategy in China, the new energy power generation technology represented by wind power is rapidly developed, the new energy generator set is connected with the grid on a large scale, and the installed ratio is rapidly improved. However, the inherent fluctuations and uncertainties in the active output of wind turbines are continuously deteriorating the frequency safety profile of the power system. Meanwhile, the factors such as economy and wind abandoning rate are considered, the wind generating set is operated in MPPT mode, and the wind generating set does not participate in inertia support and primary frequency modulation of the system, so that the problems are further aggravated. In order to realize the accurate simulation analysis of the frequency characteristics of the novel power system and the optimal design of related control strategies, a fine simulation model of the wind turbine generator and the station is necessarily required to be established.

Different from the traditional synchronous generator, the single-machine capacity of the wind turbine generator is smaller, the wind turbine generator sets are relatively dispersed, and one wind power station often comprises tens or even hundreds of wind turbine generator sets. The wind farm detailed model of all wind turbines is established, so that the complexity and the simulation calculation time geometry of the wind turbines are increased, the modeling and simulation efficiency is greatly reduced, and therefore, the development of a rapid and effective wind farm equivalent modeling method is important.

At present, researchers have proposed diversified wind farm equivalent methods to improve simulation efficiency on the premise of ensuring accuracy, but the problem of poor engineering practicability often exists. In addition, equivalent modeling and simulation of the wind power plant are aimed at steady-state operation, voltage disturbance and short-circuit fault working conditions, and research on frequency modulation working conditions is deficient.

Disclosure of Invention

The embodiment of the application provides a grouping method, device, equipment and storage medium for a new energy station, which solve the problems of low equivalent precision and low engineering practicability of a wind power plant.

The embodiment of the application provides a grouping method of new energy stations, which comprises the following steps:

Collecting wind speed data of each wind turbine in the new energy station;

Dividing wind speed data of each model wind turbine generator set by using a starting point and an ending point of an MPPT region of each model wind turbine generator set to obtain wind turbine generator sets in different wind speed regions;

dividing all wind turbines in each wind speed interval of each model into a grouping group to obtain a grouping result of the new energy station.

The embodiment of the application also provides a grouping device of the new energy station, which comprises:

the acquisition module is used for acquiring wind speed data of each wind turbine generator in the new energy station;

The dividing module is used for dividing wind speed data of each model wind turbine generator set according to the starting point and the ending point of the MPPT area of the model wind turbine generator set to obtain wind turbine generator sets in different wind speed intervals;

The grouping module is used for dividing all the wind turbines in each wind speed interval of each model into a group to obtain a grouping result of the new energy station.

The embodiment of the application also provides grouping equipment of the new energy station, which comprises: a memory and at least one processor, the memory having instructions stored therein, the memory and the at least one processor being interconnected by a line;

the at least one processor invokes the instructions in the memory to cause the grouping device of the new energy station to perform the steps of:

Collecting wind speed data of each wind turbine in the new energy station;

The embodiment of the application also provides a computer readable storage medium, wherein the computer readable storage medium stores a computer program, and the computer program realizes the following steps when being executed by a processor:

Collecting wind speed data of each wind turbine in the new energy station;

The embodiment of the application has the following beneficial effects:

According to the clustering method for the new energy station, provided by the embodiment of the application, the wind speed data of each type of wind turbine is divided through the starting point and the ending point of the MPPT area of each type of wind turbine, and the wind speed data of each wind turbine in the new energy station is replaced by wind turbines in different wind speed intervals; dividing all wind turbines in each wind speed interval of each model into a grouping group to obtain a grouping result of the new energy station. The grouping result obtained by the method has higher equivalent precision and stronger wind speed scene adaptability, and has higher engineering practicability. The grouping device, the grouping equipment and the storage medium for the new energy station can achieve the above effects.

Drawings

In order to more clearly illustrate the embodiments of the application or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, it being obvious that the drawings in the following description are only some embodiments of the application, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Wherein:

FIG. 1 is a general main circuit topology diagram of a full power wind turbine provided by an embodiment of the application;

FIG. 2 is a schematic diagram of a typical approximate functional relationship of C _p with respect to λ and β;

fig. 3 is a schematic topology diagram of a back-to-back full-power converter according to an embodiment of the present application;

fig. 4 (a) is a control block diagram of a network side controller according to an embodiment of the present application;

FIG. 4 (b) is a control block diagram of a machine side controller according to an embodiment of the present application;

fig. 5 is a schematic flow chart of a grouping method of a new energy station according to an embodiment of the present application;

FIG. 6 is a schematic diagram of a three-machine equivalent grouping result provided by an embodiment of the present application;

FIG. 7 (a) is a schematic diagram of equivalent pre-post frequency modulation response curves for a first group of wind turbines;

FIG. 7 (b) is a schematic diagram of equivalent pre-post frequency modulation response curves for a first group of wind turbines;

FIG. 7 (c) is a schematic diagram of equivalent pre-post frequency modulation response curves for a first group of wind turbines;

FIG. 8 is a schematic diagram of a typical fan speed versus active power operation;

FIG. 9 is a comprehensive inertia control block diagram;

FIG. 10 is a schematic diagram of a de-load backup mode of a wind turbine;

FIG. 11 is a pitch angle control block diagram;

fig. 12 is a frequency modulation control block diagram of the MPPT region;

FIG. 13 is a block diagram of FM control in the constant speed region and the constant power region;

FIG. 14 (a) is a waveform of a frequency change with a frequency setting of 48HZ under test conditions of inertia response characteristics of a wind turbine generator;

FIG. 14 (b) is a waveform of frequency variation with a frequency setting of 51.5HZ under test conditions of inertia response characteristics of a wind turbine generator;

FIG. 14 (c) is a waveform of frequency variation with a frequency setting of less than 50HZ under the test condition of the frequency modulation characteristic of the wind turbine generator;

FIG. 14 (d) is a waveform of frequency variation with a frequency setting greater than 50HZ under test conditions of wind turbine frequency modulation characteristics

Fig. 15 is a schematic structural diagram of a grouping device for a new energy station according to an embodiment of the present application;

Fig. 16 is a schematic structural diagram of a grouping device of a new energy station according to an embodiment of the present application;

fig. 17 is a schematic structural diagram of a computer readable storage medium according to an embodiment of the present application.

Detailed Description

The following description of the embodiments of the present application will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present application, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.

As shown in fig. 1, in the general main circuit topology diagram of a full-power wind turbine provided by the embodiment of the application, wind energy is captured by a wind turbine of the full-power wind turbine, and a permanent magnet synchronous generator is driven to generate alternating current, and then the alternating current is synchronously connected to a power grid through a back-to-back full-power converter and a machine-end transformer.

The main function of the wind turbine is to capture kinetic energy (wind energy) in the air through the wind wheel blades and convert the kinetic energy (wind energy) into mechanical energy of a direct-drive rotating system. According to the aerodynamic model, in the working wind speed interval of the wind turbine, the mechanical power P _m transmitted to the permanent magnet synchronous motor by the wind turbine is as follows:

wherein lambda is the tip speed ratio, an

P _w is wind power, ρ is air density, R is wind wheel radius, v is wind speed, β is pitch angle, ω _m is fan mechanical angular velocity, C _P is wind energy utilization coefficient, which is used to represent conversion efficiency of wind energy into mechanical energy, and is determined by tip speed ratio and pitch angle together. The maximum value of C _p given by the Betts theory is 0.593, and a typical approximate functional curve of C _p with respect to λ and β is shown in FIG. 2.

The permanent magnet synchronous generator is a core conversion device for converting mechanical energy into electric energy in a full-power wind generating set, and adopts a dq axis mathematical model under a synchronous rotation coordinate system, and a stator equation can be expressed as follows:

Where u _ds is the d-axis component of the stator voltage, u _qs is the q-axis component of the stator voltage, i _ds is the d-axis component of the stator current, i _qs is the q-axis component of the stator current, R _s is the stator resistance, L _ds is the stator d-axis inductance, L _qs is the stator q-axis inductance, ω _e is the synchronous speed, and ψ _f is the permanent magnet flux linkage.

The electromagnetic torque equation under the dq coordinate system can be expressed as:

Wherein n _p is the rotation speed of the fan; phi _ds denotes the flux linkage d-axis component; and ψ _qs denotes the flux linkage q-axis component.

The back-to-back full-power converter can realize the frequency conversion function of alternating current. The machine side converter rectifies alternating current generated by the permanent magnet synchronous generator into direct current, converts the direct current into stable power frequency alternating current through the grid side converter, and finally sends out wind power to a power grid through the machine side transformer. Fig. 3 is a schematic topology diagram of a back-to-back full-power converter according to an embodiment of the present application.

In the topology of the "back-to-back" full power converter shown in fig. 3, the converter losses are ignored and there is, according to active power conservation:

P_s＝P_dc+P_g (5)

Wherein P _s is the active power of the machine side converter, and

P_s＝u_dci_s (6)

P _dc is the active power of the dc capacitor,

P _g is the active power of the grid-side converter.

P_g＝u_dci_g (8)

Where u _dc is a dc capacitor voltage, i _s is a machine side converter current, i _dc is a dc capacitor current, C is a capacitance value of a dc capacitor, and i _g is a grid side converter current.

The output reactive power of the converter is as follows:

Wherein, P _g is the active power output by the converter, Q _g is the reactive power output by the converter, u _dg is the d-axis component of the AC voltage of the grid-side converter, u _qg is the Q-axis component of the AC voltage of the grid-side converter, i _dg is the d-axis component of the AC current of the grid-side converter, and i _qg is the Q-axis component of the AC current of the grid-side converter.

The main function of the network side controller is to maintain the stability of the direct current side voltage and output active power and reactive power to the power grid, and the alternating current voltage is as follows:

wherein v _dg is the d-axis alternating voltage component of the grid-side controller, v _qg is the q-axis alternating voltage component of the grid-side controller, R _g is the grid-side resistor, i _dg is the d-axis alternating current component of the grid-side controller, i _qg is the q-axis alternating current component of the grid-side controller, L _g is the grid-side reactance, ω _s is the synchronous speed, and u _dg is the d-axis component of the grid-side converter alternating voltage.

Adding PI control and adding a decoupled feed-forward input to the coupling term yields:

fig. 4 (a) is a control block diagram of a network side controller according to an embodiment of the present application, where the network side controller controls a d-axis component through d-axis directional power grid voltage to implement dc bus voltage control, and controls a q-axis component to implement reactive power control.

The main function of the machine side controller is to follow the active power of the permanent magnet synchronous generator and inject active and reactive current to the direct current side, and a double closed loop vector control strategy of a power outer loop and a current inner loop is adopted.

Neglecting the stator resistance of the generator, the voltage-current dynamic equation of the permanent magnet synchronous generator in the formula (3) can be rewritten as the formula (12):

in the rotating coordinate system, the active power P _s and the reactive power Q _s of the permanent magnet synchronous generator can be calculated by formula (13):

Adding PI control and coupling term to the decoupled feed-forward input results in a control block diagram of the machine side controller as shown in fig. 4 (b).

As shown in fig. 5, a flow chart of a grouping method of a new energy station according to an embodiment of the present application is shown, where the method includes:

step S501, collecting wind speed data of each wind turbine generator in a new energy station;

Specifically, in this embodiment, the new energy station is a set of all devices below a wind farm or a solar power station grid-connected point that are connected to the power system in a centralized manner, including a transformer, a bus, a line, a converter, energy storage, a wind turbine, photovoltaic power generation devices, reactive power regulation devices, auxiliary devices, and the like. The wind turbine generator is a device for generating electricity by using wind energy, and consists of a wind wheel, a generator, a gear box, a tower and the like. The wind wheel captures wind energy through the blades and drives the generator to rotate, so that mechanical energy is converted into electric energy. The gearbox then acts to increase the rotational speed and torque. The fault types of the wind turbine mainly comprise gear box faults, electric system faults, generator faults and the like. The wind speed data of each wind turbine generator in the new energy station can be acquired through the existing wind speed acquisition device or wind speed acquisition method.

Step S502, dividing wind speed data of each model wind turbine generator set by a starting point and an ending point of an MPPT region of the wind turbine generator set to obtain wind turbine generator sets in different wind speed regions;

Specifically, in this embodiment, all wind turbines are classified into wind turbines of different models according to the models of all wind turbines in the energy station, so as to obtain a wind turbine model classification result. And dividing the wind speed data of all the wind turbines in the classification result of each wind turbine model into wind speed data of different wind speed intervals according to the starting point and the ending point of the MPPT area of the wind turbine model, and obtaining wind turbines corresponding to the wind speed data of different wind speed intervals according to the corresponding relation between the wind speed data and the wind turbines.

It should be noted that in different wind speed ranges, the frequency modulation response of the wind turbine generator is different under the same disturbance frequency disturbance. Besides the fact that the wind turbine generator in the wind speed interval before the MPPT area starting point of the wind turbine generator in the model does not respond to frequency disturbance, the wind turbine generator in the rest wind speed intervals jointly provides active adjustment quantity through virtual inertia control and sagging control in the climbing stage after the frequency disturbance occurs. After the frequency climbing is finished, the virtual inertia control exits, and only the sagging control continues to act, so that the absolute value of the active adjustment quantity at the moment is suddenly reduced and enters a stable state, and the active adjustment quantity at the frequency recovery stage also changes according to the slope. The active power regulation speed of the wind turbine running in the constant rotation speed zone and the constant power zone is slower than that of the MPPT zone due to the action speed of the pitch angle. Therefore, according to the frequency modulation response characteristic of the full-power wind turbine, the wind turbine in the wind speed range before the MPPT area starting point of the wind turbine is not involved in frequency modulation (2) the pitch angle control is adopted to realize load shedding operation, and the active regulation speed when the wind turbine is involved in system frequency modulation is obviously lower than the situation of adopting overspeed load shedding control. Taking the (1) and the (2) as clustering characteristics, and dividing the wind turbines in different wind speed intervals for each model of wind turbine.

And S503, dividing all wind turbines in each wind speed interval of each model into a group to obtain a grouping result of the new energy station.

Specifically, in this embodiment, as shown in fig. 6, a schematic diagram of a three-machine equivalent grouping result provided by the embodiment of the present application is shown, where a wind motor component in a wind speed interval before a start point of an MPPT area of a wind turbine of the model is a1 st group, a wind motor component in an MPPT area of the wind turbine of the model is a 2 nd group, and a wind motor component in a wind speed interval after the start point of the MPPT area of the wind turbine of the model is a 3 rd group.

The wind turbine generator sets with the full power of 1.5MW respectively have corresponding wind speed dividing points of 4.8326m/s and 8.05m/s. The effectiveness of the grouping method provided by the embodiment is verified, 10 corresponding wind speeds are selected according to the equidistant active output in the corresponding wind speed intervals of the 1 st group, the 2 nd group and the 3 rd group respectively, and a single-machine equivalent method is adopted to equivalent each group of fans to an equivalent machine, so that an electromagnetic transient model of the electromagnetic transient model is established. Then, a unified frequency disturbance condition (the frequency step drops to 49.5Hz, lasts for 30s and recovers) is set, and the frequency modulation response conditions of the wind power generator group before and after the equivalent are tested, and the result is shown in figure 7.

As can be seen from the comparison result of FIG. 7, the frequency modulation response of the three groups of fans corresponding to the single machine equivalent model is consistent with that of the detailed model, and the calculated average absolute deviation of the disturbance overall process is 0.0023%, 0.0257% and 0.051% respectively, which indicates that the wind turbines working in the wind speed section before the start point of the MPPT area of the wind turbine model, the wind turbines working in the MPPT area of the wind turbine model and the wind speed section after the end point of the MPPT area of the wind turbine model can be respectively equivalent to an equivalent machine, and the equivalent precision is higher.

According to the grouping method of the new energy station, wind speed data of wind turbines of each model are divided through the starting point and the ending point of the MPPT area of the wind turbine of each model, and wind speed data of each wind turbine in the new energy station are replaced by wind turbines in different wind speed intervals; dividing all wind turbines in each wind speed interval of each model into a grouping group to obtain a grouping result of the new energy station. The grouping result obtained by the method has higher equivalent precision and stronger wind speed scene adaptability, and has higher engineering practicability.

In some embodiments, the method further comprises:

And obtaining the equivalent machine parameters of each wind turbine group, and establishing a single machine equivalent model according to the equivalent machine parameters.

In some embodiments, obtaining the equivalent machine parameters for each wind farm includes:

Wherein S _eq is equivalent machine capacity; p _eq is the equivalent machine active power; s _i is the capacity and active power of the ith wind turbine generator in the current cluster; p _i is the active power of the ith wind turbine generator in the current cluster; n is the number of wind turbines in the current cluster.

Specifically, in this embodiment, according to wind speed data of each wind turbine, after dividing wind turbine components in a wind power plant into three groups by taking a start point and an end point of an MPPT region of a current model wind turbine as dividing point wind speeds, respectively calculating equivalent machine parameters of each wind turbine group based on a formula (14) and establishing a single machine equivalent model, and calculating equivalent cable parameters according to a principle that power losses of current collecting networks before and after equivalent are equal, thereby completing three machines equivalent of the wind power plant. For the situation that the number of wind turbines in an individual cluster is 0 in certain wind speed scenes, the number of equivalent turbines can be reduced to 1 or 2 according to the situation.

In some embodiments, the method further comprises:

in a wind speed interval before the MPPT zone starting point of each model of wind turbine, the running state of the wind turbine is a starting zone;

In a wind speed interval between the starting point and the ending point of the MPPT area of each model of wind turbine generator, the running state of the wind turbine generator is the MPPT area;

And in a wind speed interval after the MPPT area end point of each model of wind turbine, the running state of the wind turbine is a constant rotating speed area and a constant power area.

Specifically, in the embodiment, the variable speed constant frequency wind turbine generator allows the rotation speed of the prime motor directly connected with the generator to change within a certain range, so that the prime motor can conveniently work at an optimal working point, and the maximum utilization of wind energy is realized. The running state of the wind turbine generator can be divided into: a typical fan speed-active power operating curve is shown in fig. 8 for the startup zone, MPPT zone, constant speed zone, and constant power zone.

When the rotating speed of the wind turbine is in the AB interval in FIG. 8, the fan is operated in the maximum wind energy tracking state, and the pitch angle of the fan is 0 degrees. According to the relation between the wind energy utilization coefficient, the pitch angle and the rotor rotating speed, each wind speed in the interval has a unique corresponding optimal rotating speed to enable C _P to reach C _Pmax, and the MPPT control curve in the interval can be obtained by connecting all the optimal rotating speeds. As shown in section BC of fig. 8, which is a constant rotation speed control region of the wind turbine, it can be seen from equation (1) that, when the wind turbine reaches the rated rotation speed, the active output can still be increased with the increase of the wind speed. Therefore, the wind turbine generator system in the working area maintains the rotating speed at the rated rotating speed until the active power output reaches the rated power. As shown in the section CD of FIG. 8, which is a constant power control region of the wind turbine, the active power of the wind turbine is maximized at this time, and the pitch angle needs to be increased according to the wind speed condition to avoid the wind turbine running in an overload state.

In some embodiments, in a wind speed interval before the MPPT zone starting point of each model of wind turbine, the wind turbine does not participate in frequency modulation of the new energy grid-connected power generation system;

in a wind speed interval between the starting point and the ending point of the MPPT area of each model of wind turbine, the wind turbine performs load shedding through overspeed control to participate in frequency modulation of the new energy grid-connected power generation system;

In some embodiments, the motor group performs load shedding through overspeed control to participate in frequency modulation of the new energy grid-connected power generation system, and the method comprises the following steps:

during steady-state operation, the rotor is overspeed to the load-shedding operation rotating speed based on the current wind speed and the load-shedding standby coefficient, the mechanical power and the electromagnetic power are balanced, and the rotating speed is kept stable;

When the system frequency drops, the wind energy utilization coefficient is improved until the mechanical power captured by the wind turbine and the electromagnetic power output by the generator reach new balance;

when the system frequency rises, the rotating speed of the wind turbine generator is increased, and the active output is reduced.

And in a wind speed interval after the MPPT area end point of each model of wind turbine, the wind turbine performs load shedding standby through pitch-variable angle control to participate in frequency modulation of the new energy grid-connected power generation system.

In some embodiments, the wind turbine generator performs load shedding reserve to participate in frequency modulation of the new energy grid-connected power generation system through pitch-variable angle control, and the method comprises the following steps:

When the system frequency drops or rises, the pitch angle control adjusts the pitch angle in real time until the rotating speed is stabilized at the rated rotating speed again.

Specifically, in this embodiment, under the condition of not considering cooperation with the energy storage device, the current method of the wind turbine participating in frequency modulation is mainly divided into rotor kinetic energy control and power standby control according to energy sources. The rotor kinetic energy control mainly comprises virtual inertia control and sagging control, and the power standby control mainly comprises overspeed load shedding control and pitch angle control.

The virtual inertia control simulates the rotational inertia characteristic of the synchronous generator, so that the wind turbine generator can utilize the rotor kinetic energy stored by the fan rotating system to support active power adjustment, and participate in system frequency modulation control. As can be seen from fig. 9, the virtual inertia control response is the rate of change of the system frequency, which can be specifically expressed as:

Wherein Δp ₁ is the active output reference value adjustment quantity of the virtual inertia control output, f _db1 is the frequency-up dead zone, Δf is the system frequency deviation, f _db2 is the frequency-down dead zone, K _1u is the frequency-up virtual inertia control coefficient, P ₀ is the active output of the wind turbine generator set in steady state operation, K _1d is the frequency-down virtual inertia control coefficient, f is the system frequency, and t is time.

The basic principle of droop control is to add an active power reference value regulating quantity proportional to the system frequency deviation on the basis of the active power reference value of the wind turbine generator, so as to participate in system frequency modulation. As can be seen from fig. 9, the droop control can be expressed as:

Wherein Δp ₂ is the active output reference adjustment amount of the droop control output, K _2u is the up-regulated droop control coefficient, and K _2d is the down-regulated droop control coefficient.

Meanwhile, virtual inertia control and sagging control, namely comprehensive inertia control, are adopted, so that the kinetic energy of the rotor can actively respond to the frequency change of the system, and the frequency stability of the power system is improved. However, during the rotor speed drop to the limit or frequency recovery, the rotor needs to absorb active power to increase the speed, at which time there is a risk of a secondary drop in frequency.

If the wind turbine is to realize primary frequency modulation in the true sense, a certain frequency modulation standby power must be reserved in steady state operation, and the method for load shedding operation of the wind turbine mainly comprises pitch angle control and overspeed load shedding control. As can be seen from fig. 2, the wind energy utilization ratio C _p of the wind turbine generator is determined by the tip speed ratio λ and the pitch angle β, and the power reserve and release can be achieved by indirectly changing the wind energy utilization coefficient by changing the tip speed ratio and the pitch angle.

The curve of the wind energy utilization coefficient C _p about the pitch angle and the tip speed ratio is shown in fig. 10, and as the pitch angle of the fan increases, the working point of the fan is changed from the point A to the point B, and the output power is reduced. Based on the principle, the variable pitch angle control shown in fig. 11 can realize the load shedding operation of the fan according to the set load shedding standby coefficient eta _del, and can indirectly adjust the active output by adjusting the pitch angle in real time when the frequency disturbance occurs in the system.

As shown in formula (17), when the pitch angle of the wind turbine generator is constant, under each wind speed condition, the unique fan rotating speed omega _opt enables the fan to reach the optimal tip speed ratio, and then the fan reaches the maximum wind energy utilization state.

If the rotating speed of the fan is controlled to deviate from the optimal rotating speed omega _opt, the power load shedding of the unit can be realized, and the power standby is provided for the frequency modulation of the fan. However, if the wind turbine generator is used to realize load shedding, the stability of the system will be reduced, so that the wind turbine generally adopts overspeed control to realize active load shedding. As shown in FIG. 10, after overspeed control is adopted, the fan operating point is moved from the point A to the point C, the wind energy utilization rate is reduced from C _Pmax to C _Pdel according to the load shedding standby coefficient, and when the frequency disturbance occurs in the system, the active force can be reduced or increased through further overspeed or deceleration, so that primary frequency modulation of the wind turbine generator is realized.

Under overspeed load shedding control, the wind turbine generator system can convert rotor kinetic energy into electromagnetic power to support the system frequency while releasing the standby power to support the system frequency. Therefore, the frequency modulation response speed is higher, but is limited by the upper and lower limits of the rotating speed, and when the wind turbine generator participates in the system frequency modulation through pitch angle changing control, frequent pitch angle adjustment can cause accelerated abrasion of a mechanical system of the wind turbine, so that the operation life of the wind turbine generator is reduced. In addition, pitch angle control includes mechanical control components, resulting in a greater inertia and slower speed of pitch angle changes. In summary, in a low wind speed scene, in order to ensure the stability of the active output of the wind turbine, the wind turbine does not participate in system frequency modulation; under the medium wind speed scene, namely after overspeed load shedding according to the load shedding standby coefficient, the rotating speed does not exceed the upper limit, and the load shedding is implemented by adopting overspeed control preferentially; in a high wind speed scenario, i.e. when the load shedding reserve requirement cannot be met by only adopting overspeed control, load shedding reserve should be implemented by adopting pitch angle control.

The frequency modulation response characteristic of the wind turbine generator is determined by a control strategy, control parameters and an initial running state. The key control parameters mainly comprise: the upper and lower frequency modulation dead zones f _db1 and f _db2, the upper and lower virtual inertia coefficients K _1u and K _1d, the upper and lower droop coefficients K _2u and K _2d, the load shedding reserve coefficient eta _del and the upper and lower active regulation limits dP _max and dP _min.

The upper active regulation limit is mainly determined by the load shedding reserve coefficient, and in consideration of economic factors, the upper active regulation limit is generally equal to the load shedding amount in value, so that the load shedding reserve coefficient has similar influence on the frequency modulation response characteristic of the wind turbine generator. And then, respectively adopting disturbance working conditions of frequency step change, slope change and step change, and carrying out detailed sensitivity analysis on the frequency modulation dead zone, the virtual inertia coefficient, the sagging coefficient and the load shedding standby coefficient.

The frequency modulation dead zone mainly influences the sensitivity degree of the wind turbine generator to participate in system frequency adjustment, the response delay of the wind turbine generator after disturbance occurs can be obviously increased by the increase of the frequency modulation dead zone, but frequent action of frequency modulation control of the wind turbine generator is caused by the fact that the frequency modulation dead zone is too small, and the mechanical loss and the frequency oscillation risk are increased. According to the specification of GB/T40595-2021 about the primary frequency modulation dead zone of the new energy station, the primary frequency modulation dead zone of the wind turbine generator set is set within the range of +/-0.03 Hz-0.1 Hz, and is determined according to actual requirements. In an actual wind power station, except for partial experimental scenes, the frequency modulation dead zone of most wind power stations which enable frequency modulation control in China is set to be about +/-0.1 Hz at present, and almost no system frequency modulation is involved. However, under the background that the demands of the wind turbine generator for participating in frequency modulation gradually increase, future frequency modulation dead zones tend to gradually decrease according to the demands.

The virtual inertia response system frequency change rate, and from the system frequency, the virtual inertia coefficient mainly affects the maximum frequency change rate ROCOF the system and the frequency nadir. The droop control provides active support at longer time scales in response to the frequency offset of the system, affecting the frequency of the system at transient steady state. The increase of the virtual inertia coefficient will increase the active adjustment quantity of the wind turbine generator set when the frequency is changed, and the increase of the sagging coefficient will increase the active adjustment quantity in the stable section after the frequency step. According to GB/T19963.1-2021, the first part of the technical specification of wind farm access to the electric power system: the regulation of the onshore wind power on the inertia response and primary frequency modulation of the wind power plant is that the equivalent inertia time constant T _J of the wind power set is generally set to be in the range of 8-12s, and the equivalent inertia time constant T _J converted into the virtual inertia control coefficient K ₁ is in the range of 0.16-0.24; the active frequency modulation coefficient K ₂ of the wind turbine is generally set in the range of 10-50. The virtual inertia coefficient and the sagging control coefficient are increased, so that the wind turbine generator can release more rotor kinetic energy and standby power when the system generates frequency disturbance, but secondary reduction of frequency can be caused under the condition that active standby is insufficient, and the safety of the system frequency is not facilitated.

The load shedding reserve coefficient simultaneously influences the active output of the wind turbine generator in a steady state operation state and the active variation under frequency disturbance. The larger load shedding standby coefficient means larger active up-regulating space, but also reduces active output in steady state operation, and restricts economic operation of the wind turbine generator.

In conclusion, the influence of the frequency modulation key parameters on the frequency modulation response of the wind turbine is remarkable, and the accuracy of the parameters needs to be fully considered when the wind turbine or the station is subjected to fine modeling.

The steady-state operation of the full-power wind turbine generator can be divided into four working operation regions, namely a starting region, an MPPT region, a constant rotating speed region and a constant power region according to a wind speed scene. And the four areas divide the coordination relation of frequency modulation control.

A) Start-up region:

In this working interval, the wind speed and the rotation speed of the blower are lower, so the active force and the kinetic energy of the rotor of the blower are also at lower level. If the system frequency is reduced at this time, the wind turbine responds to the increase in active output of the system frequency, and the reduction in rotational speed may cause the wind turbine to stall. In order to ensure the stable operation of the wind turbine, the wind turbine in the area does not implement load shedding standby and does not participate in system frequency modulation. The in-section relief coefficient η _del, the virtual inertia control coefficient K ₁, and the droop control coefficient K ₂ are all set to 0.

B) MPPT area:

In the working interval, the wind speed and the rotating speed of the fan are improved, and the pitch angle of the fan is always maintained at 0 degree under MPPT control. As shown in FIG. 12, the wind turbine generator in the interval adopts overspeed load shedding control to realize load shedding operation, and participates in system frequency modulation in cooperation with comprehensive inertia control, and the specific principle is as follows:

when the transmission loss is ignored, the wind turbine captures wind energy and transmits the wind energy to the permanent magnet synchronous motor, and the mechanical power is as follows:

In the starting and running process of the wind turbine generator, the motion process of the rotor always follows the following swinging equation:

wherein J is the rotational inertia of the wind turbine generator, omega _r is the rotor speed, and P _e is the electromagnetic power output by the generator.

The load shedding power tracking equation of the wind turbine generator in the overspeed load shedding mode is as follows:

k_del＝(1-η_del)k_opt (21)

Where P _del is the off-load operating power, k _del is the off-load operating tracking coefficient, k _opt is the maximum power tracking coefficient, and η _del is the off-load backup coefficient.

During steady-state operation, overspeed load shedding control enables the rotor to overspeed to the load shedding operation rotating speed based on the current wind speed and the load shedding standby coefficient, and at the moment, the mechanical power and the electromagnetic power are balanced, and the rotating speed is kept stable. According to equations (18), (20) and (21), when the system frequency drops, the integrated inertia control will increase the electromagnetic power output, resulting in a reduced rotational speed and an increased wind energy utilization factor, until the mechanical power captured by the wind turbine and the electromagnetic power output by the generator reach a new balance. Otherwise, when the system frequency rises, the fan reduces the active output by further increasing the rotating speed and continuously participates in frequency modulation.

C) Constant rotation speed region and constant power region:

In the constant rotation speed area, the rotation speed of the fan is kept unchanged, but the active output of the wind turbine generator can still be continuously increased along with the increase of the wind speed. In the constant power area, the active output of the wind turbine generator reaches the upper limit, and in order to avoid overload of the converter, the pitch angle control maintains the active output of the wind turbine generator at rated power by increasing the pitch angle. Because the fan speed reaches the rated speed in the two working intervals, overspeed load shedding control cannot be adopted to implement load shedding. Therefore, as shown in fig. 13, the wind turbine generator in the interval adopts pitch angle control to realize load shedding operation, and participates in system frequency modulation in cooperation with comprehensive inertia control. When the system frequency drops or rises, the integrated inertia control correspondingly increases or decreases the electromagnetic power output, resulting in a rotational speed deviating from a steady state value. At this time, the PI control link in the pitch angle control adjusts the pitch angle in real time until the rotation speed is stabilized at the rated rotation speed again.

The frequency modulation response of the wind turbine generator in different working intervals is cooperatively realized by different frequency modulation control methods, so that the research on the frequency modulation characteristics of the wind turbine generator in different wind speed scenes and frequency disturbance is the basis for carrying out equivalent modeling of the wind power plant. Based on the main circuit topology, steady-state operation control and frequency modulation control structure of a certain type of full-power wind turbine, the report establishes an electromagnetic transient model of the full-power wind turbine on a MATLAB/Simulink software platform, and designs a simulation test scene based on GB/T36994-2018 "wind turbine grid adaptability test procedure", specifically as follows:

And connecting the wind turbine with an infinite system, and injecting a frequency disturbance signal into a frequency modulation control module of the wind turbine at 10 s. In order to prevent the active power adjustment quantity from reaching the upper limit and the lower limit under the frequency modulation control action of the wind turbine generator and affecting the subsequent characteristic analysis, the section adopts smaller frequency disturbance amplitude for testing. For the frequency modulation characteristic test, setting the frequency to be respectively up and down to 49.5Hz and 50.5Hz, lasting for 30s and recovering to 50Hz; for the inertia response characteristic test, the set frequency is ramped up and down at a slope of + -0.5 Hz/s, held for 15s after the frequency reaches 49.5Hz and 50.5Hz, and then restored to 50Hz at an opposite slope. Based on the cut-in and cut-out wind speeds of the wind turbine generator, 42 wind speeds are selected at proper intervals in a wind speed range of 3m/s-22m/s, and response curves are respectively tested and drawn. Each curve corresponds to a frequency modulation response result at one wind speed, and the frequency modulation response of the wind turbine generator sets in different wind speed ranges is obviously different under the frequency disturbance of the same disturbance.

The wind turbine mainly takes part in frequency modulation by the cooperation of overspeed load shedding control and pitch angle control and droop control. Because the wind turbine running in the starting area does not implement load shedding and does not participate in frequency modulation, the wind turbine running in the starting area has no response to frequency disturbance. And when the frequency is subjected to step disturbance, the wind turbine generator system only calls the kinetic energy of the rotor through droop control and the standby active power to participate in frequency modulation. Because the active regulation speed of the wind turbine generator set under the control combination is higher, the transient response process of the wind turbine generator set is similar to step change. When the wind turbine works in a constant rotating speed area and a constant power area, load shedding can only be implemented through pitch angle control, and the wind turbine is matched with droop control to participate in frequency modulation. The active power is regulated for a longer time due to the slower action speed of the pitch angle of the fan.

Except that the wind turbine running in the starting area does not respond to the frequency disturbance, the wind turbine running in other intervals jointly provides active adjustment quantity by virtual inertia control and sagging control in the climbing stage after the frequency disturbance occurs. After the frequency climbing is finished, the virtual inertia control exits, and only the sagging control continues to act, so that the absolute value of the active adjustment quantity at the moment is suddenly reduced and enters a stable state, and the active adjustment quantity at the frequency recovery stage also changes according to the slope. The active power regulation speed of the wind turbine running in the constant rotation speed zone and the constant power zone is slower than that of the MPPT zone due to the action speed of the pitch angle.

From the above analysis of the frequency modulation response characteristics of the full-power wind turbine generator, the wind turbine generator working in the starting region, the MPPT region, the constant rotation speed region and the constant power region has obvious clustering characteristics, and the main reasons can be summarized as two points: (1) The wind turbine generator set in the starting area does not participate in frequency modulation (2) and adopts pitch angle control to realize load shedding operation, and the active regulation speed when the wind turbine generator set is matched with the system to participate in frequency modulation is obviously lower than that of the wind turbine generator set adopting overspeed load shedding control.

In order to fully verify the effectiveness of the full-power wind farm three-machine equivalent modeling method suitable for frequency characteristic analysis, a certain 33 multiplied by 1.5MW full-power wind farm is taken as a test object, and a detailed model, a single-machine equivalent model and the three-machine equivalent model are established based on a MATLAB/Simulink platform. Then, two groups of wind speed data are randomly extracted from a 2022-year database of a certain wind power plant, and wind turbines are clustered based on the clustering method provided by the application, so that equivalent machine parameter calculation is completed. Finally, according to relevant standards about wind turbine inertia response characteristic test and wind turbine frequency modulation characteristic test in GB/T36994-2018 wind turbine power grid adaptability test procedure, detailed simulation comparison is carried out on wind turbine frequency modulation response characteristics under three modeling modes, specific frequency disturbance working conditions are shown in tables 1 and 2, and as shown in FIG. 14 (a), frequency variation waveforms with frequency set value of 48HZ under wind turbine inertia response characteristic test working conditions are shown; fig. 14 (b) is a waveform of frequency variation with a frequency setting value of 51.5HZ under the test condition of inertia response characteristics of the wind turbine generator; FIG. 14 (c) is a waveform of frequency variation with a frequency setting of less than 50HZ under the test condition of the frequency modulation characteristic of the wind turbine generator; fig. 14 (d) shows a frequency variation waveform with a frequency setting value greater than 50HZ under the test condition of the frequency modulation characteristic of the wind turbine generator.

TABLE 1 wind turbine inertia response characteristic test condition

Table 2 frequency modulation characteristic test working condition of wind turbine generator

The transient state and steady state responses of the wind power plant equivalent model established by the traditional single machine equivalent method have larger deviation in the frequency disturbance period. The method is characterized in that after all the wind turbine generators are equivalent to one equivalent machine, the active power output of the equivalent machine is the average active power output of all the wind turbine generators, the frequency modulation response characteristic of the equivalent machine can only be represented as one of three groups of the wind turbine generators, and the frequency modulation response characteristic of the actual wind power plant is the sum of the three groups of the characteristics. Specifically, the transient state deviation is derived from the difference between overspeed load shedding control and pitch angle control in the active regulation speed, and the steady state deviation is mainly derived from the fact that the wind turbine generator set in the starting area does not provide active regulation quantity in frequency disturbance. On the other hand, the wind power plant equivalent model established by the three-machine equivalent method provided by the application obviously improves the equivalent precision of the wind power plant, and shows good adaptability, accuracy and practicability of the method.

As shown in fig. 15, a schematic structural diagram of a grouping device for a new energy station according to an embodiment of the present application is shown, where the device 1500 includes:

The acquisition module 1501 is used for acquiring wind speed data of each wind turbine generator in the new energy station;

the dividing module 1502 is configured to divide wind speed data of each model wind turbine with a start point and an end point of an MPPT region of the model wind turbine to obtain wind turbines in different wind speed intervals;

The grouping module 1503 is configured to divide all wind turbines in each wind speed interval of each model into a group, and obtain a grouping result of the new energy station.

In some embodiments, the apparatus further comprises:

the building module is used for obtaining the equivalent machine parameters of each wind turbine group and building a single machine equivalent model according to the equivalent machine parameters.

In some embodiments, the setup module is further to:

Obtaining equivalent machine parameters of each wind turbine group comprises the following steps:

In some embodiments, the apparatus further comprises:

The running state dividing module is used for dividing the running state of the wind turbine into a starting region in a wind speed region before the starting point of the MPPT region of each model wind turbine;

In some embodiments, the apparatus further comprises:

The frequency modulation module is used for enabling the wind turbine generators not to participate in frequency modulation of the new energy grid-connected power generation system in a wind speed interval before the MPPT area starting point of each model wind turbine generator;

In some embodiments, the frequency modulation module is further to:

For other details of implementing the above technical solution by each module in the grouping device of the new energy station, reference may be made to the description in the above provided grouping method of the new energy station, which is not repeated here.

As shown in fig. 16, a schematic structural diagram of a cluster tool of a new energy station according to an embodiment of the present application, where the cluster tool 1600 of the new energy station may have relatively large differences due to different configurations or performances, may include one or more processors (central processing units, CPU) 1601 (e.g., one or more processors) and a memory 1602, one or more storage mediums 1603 (e.g., one or more mass storage devices) storing application programs 16031 or data 16032. Wherein the memory 1602 and storage medium 1603 may be transitory or persistent storage. The program stored on the storage medium 1603 may include one or more modules (not shown), each of which may include a series of instruction operations in the cluster tool 1600 of the new energy station. Still further, the processor 1601 may be configured to communicate with a storage medium 1603, and execute a series of instruction operations in the storage medium 1603 on the cluster tool 1600 of the new energy station to implement the steps of:

Collecting wind speed data of each wind turbine in the new energy station;

The cluster tool 1600 of the new energy station may also include one or more power supplies 1604, one or more wired or wireless network interfaces 1605, one or more input/output interfaces 1606, and/or one or more operating systems 16033, such as Windows Serve, mac OS X, unix, linux, freeBSD, and the like. It will be appreciated by those skilled in the art that the configuration of the cluster tool of the new energy station shown in fig. 16 is not limiting of the cluster tool of the new energy station provided by the present application, and may include more or less components than those illustrated, or may combine certain components, or may be arranged in different components.

For further details regarding implementation of the above technical solution by the processor 1601 in the grouping device of the new energy station, reference may be made to the description in the above-provided grouping method of the new energy station, which is not repeated here.

In some embodiments, as shown in fig. 17, a schematic structural diagram of a computer readable storage medium according to an embodiment of the present application is provided, where a readable computer program 1701 is stored on the storage medium; the computer program 1701 may be stored in the storage medium in the form of a software product, and includes several instructions for causing a computer device (which may be a personal computer, a service machine, or a network device) or a processor (processor) to perform the following steps:

Collecting wind speed data of each wind turbine in the new energy station;

And the aforementioned storage medium includes: various media capable of storing program codes, such as a usb disk, a removable hard disk, a magnetic or optical disk, a ROM (Read-Only Memory), a RAM (Random Access Memory), or a terminal device such as a computer, a service machine, a mobile phone, a tablet.

Those skilled in the art will appreciate that all or part of the processes in the methods of the above embodiments may be implemented by a computer program for instructing relevant hardware, where the program may be stored in a non-volatile computer readable storage medium, and where the program, when executed, may include processes in the embodiments of the methods described above. Any reference to memory, storage, database, or other medium used in embodiments provided herein may include non-volatile and/or volatile memory. The nonvolatile memory can include Read Only Memory (ROM), programmable ROM (PROM), electrically Programmable ROM (EPROM), electrically Erasable Programmable ROM (EEPROM), or flash memory. Volatile memory can include Random Access Memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in a variety of forms such as Static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double Data Rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (SYNCHLINK) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), among others.

The technical features of the above embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.

The foregoing examples illustrate only a few embodiments of the application and are described in detail herein without thereby limiting the scope of the application. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the application, which are all within the scope of the application. Accordingly, the scope of protection of the present application is to be determined by the appended claims.

Claims

1. A method for grouping new energy stations, the method comprising:

Collecting wind speed data of each wind turbine in the new energy station;

2. The method of grouping new energy sites of claim 1, further comprising:

3. The method for grouping new energy stations according to claim 2, wherein the obtaining the equivalent machine parameters of each wind turbine group includes:

4. The method of grouping new energy sites of claim 1, further comprising:

5. The method for grouping new energy stations according to claim 4, wherein the wind turbines do not participate in the frequency modulation of the new energy grid-connected power generation system in a wind speed interval before the start point of the MPPT area of each model wind turbine;

6. The method for grouping new energy stations according to claim 5, wherein the motor group performs load shedding to participate in the frequency modulation of the new energy grid-connected power generation system through overspeed control, and the method comprises the following steps:

7. The method for grouping new energy stations according to claim 5, wherein the wind turbine generator performs load shedding backup to participate in frequency modulation of the new energy grid-connected power generation system through pitch-variable angle control, and the method comprises the following steps:

8. A cluster apparatus for a new energy station, the apparatus comprising:

9. A new energy station grouping apparatus, characterized in that the new energy station grouping apparatus comprises: a memory and at least one processor, the memory having instructions stored therein, the memory and the at least one processor being interconnected by a line;

the at least one processor invokes the instructions in the memory to cause the grouping device of the new energy station to perform the steps of the new energy station grouping method of any one of claims 1-7.

10. A computer readable storage medium having stored thereon a computer program, characterized in that the computer program when executed by a processor realizes the steps of the new energy station grouping method according to any of claims 1-7.