A method and device for flexible control of wind power stations in power systems with a high proportion of new energy

Abstract

The present invention belongs to the technical field of power system stability control, and specifically relates to a method and device for flexible control of wind power stations in a power system with a high proportion of renewable energy. The method changes the power tracking mechanism of the wind turbine generator set belonging to the wind power station to make it operate at a predetermined power point below the maximum power point, thereby ensuring high efficiency while storing a certain capacity of standby power that can be used for the frequency regulation needs of the power system, thereby enhancing the flexibility of the wind power station output and enabling the wind power station to have real-time frequency response and the ability to cope with unexpected load fluctuations. The method provides an effective method and means for the dispatching of wind power stations in new power systems with a high proportion of renewable energy, and helps to improve the level of safe and stable control of new power systems.

Description

Technical Field

[0001] The present invention belongs to the technical field of power system stability control, and specifically relates to a method and device for flexible control of a wind power station in a power system with a high proportion of renewable energy. Background Art

[0002] my country has proposed the strategic goal of reaching carbon peak by 2030 and carbon neutrality by 2060, and requires the construction of a new power system with new energy as the main body to achieve this goal. In the new power system, on the one hand, the proportion of new energy power generation such as wind power, which has zero-carbon characteristics, will gradually increase, and in some local areas, the installed capacity of new energy power generation will even exceed the corresponding load; on the other hand, the power grid's ability to absorb and regulate high-proportion new energy needs to be further strengthened to ensure that new energy power generation such as wind power should be fully developed. The contradiction between new energy power generation and the power grid's absorption capacity has put forward high requirements for the dispatch of new energy power sources. For new power systems with a high proportion of new energy (the so-called high proportion is relative to the traditional power system, and the proportion of new energy power sources such as wind power and photovoltaic power in the entire power system power supply has been relatively increased to a certain high proportion (for example, 30%)), the dispatch of wind power stations must meet the principle of high efficiency, that is, the wind turbines belonging to the wind power station should efficiently convert wind energy into electrical energy, and at the same time meet the principle of flexibility, that is, the wind power station can quickly and flexibly adjust its output according to the peak regulation and frequency regulation needs of the power system.

[0003] How to dispatch wind power stations efficiently and flexibly is a key technical issue in building a new power system and making it operate safely and stably. At present, the wind turbines belonging to wind power stations adopt the maximum power tracking mechanism, that is, when the wind speed is lower than the rated wind speed, the maximum wind energy is obtained by variable speed operation, and when the wind speed exceeds the rated wind speed, the wind energy corresponding to the rated power of the unit is obtained by controlling the pitch angle. The advantage of this operation mode of wind power stations is high efficiency, and the disadvantage is insufficient flexibility. Especially when wind power stations account for a high proportion of the new power system and there are no other peak-shaving and frequency-regulating resources in the system, it is very easy for wind power stations to fail to respond to power dispatching instructions such as frequency regulation, increase or decrease power output, etc., causing frequency over-limit, difficulty in real-time power balance, and even causing power system instability accidents. So far, power dispatching agencies are in the exploratory stage on how to efficiently and flexibly dispatch wind power stations in new power systems with a high proportion of new energy, and there are no effective, mature, and standardized methods and technical means. Therefore, in order to effectively solve the problem of wind power station dispatching in new power systems with a high proportion of new energy, the present invention proposes a flexible control method for wind power stations in power systems with a high proportion of new energy. By changing the power tracking mechanism of the wind turbine generator set belonging to the wind power station, it is operated at a predetermined power point below the maximum power point. While ensuring high efficiency, a certain capacity of standby power that can be used for the frequency regulation needs of the power system is stored, which enhances the flexibility of wind power station output and enables the wind power station to have real-time frequency response and the ability to cope with unexpected load fluctuations. This method provides an effective method and means for the dispatching of wind power stations in new power systems with a high proportion of new energy, and helps to improve the level of safe and stable control of new power systems. Summary of the invention

[0004] The purpose of the present invention is to solve the above problems existing in the prior art and to provide a method and device for flexible control of wind power stations in a power system with a high proportion of new energy.

[0005] To achieve the above objectives, the present invention provides the following technical solutions:

[0006] A method for flexible control of wind power stations in a power system with a high proportion of renewable energy is divided into the following steps:

[0007] S1. Obtain status data of a wind turbine generator set belonging to a wind power station, including a wind turbine generator set output power measurement value, a wind turbine generator set rotation speed measurement value, and a pitch angle measurement value.

[0008] Assume that the number of wind turbines in a wind power station is N, the sequence number of the wind turbine is i, and the state data set Gen_Set of the i-th wind turbine is i for:

[0009] Gen_Set i = {P w,i ,ω r,i,β i |i∈(1,2,…,N)},

[0010] Among them, P w,i is the output power measurement value of the i-th wind turbine generator set, ω r,i is the measured speed value of the i-th wind turbine generator set, β i is the measured value of the pitch angle of the i-th wind turbine generator set.

[0011] S2. Determine the optimal rotation speed value of the wind turbine generator set according to the status data of the wind turbine generator set belonging to the wind power station obtained in S1.

[0012] Since the output power of wind turbines is closely related to air density, blade swept area, equivalent wind speed, wind energy conversion efficiency of wind turbines, etc., we have:

[0013]

[0014] Among them, A i is the area swept by the blades of the i-th wind turbine, C p,i is the wind energy conversion efficiency coefficient of the i-th wind turbine generator set, which is the tip speed ratio λ of the i-th wind turbine generator set i and pitch angle β i The nonlinear function, ρ i is the air density at the i-th wind turbine, v eq,i is the equivalent wind speed of the i-th wind turbine.

[0015] The wind energy conversion efficiency coefficient C of the i-th wind turbine generator set is p,i for:

[0016]

[0017] Since the wind energy conversion efficiency coefficient C of the wind turbine p,i is the tip speed ratio λ i and pitch angle β i is a nonlinear function, so the tip speed ratio λ of the i-th wind turbine i for:

[0018] λ i =f i (C p,i ,β i ),

[0019] Among them, f i (·,·) represents the wind energy conversion efficiency coefficient C of the i-th wind turbine p,i and pitch angle β i Tip speed ratio λ i The mapping relationship is the same below.

[0020] Assume that the wind energy conversion efficiency coefficient C of the i-th wind turbine is p,i The maximum value is C pm,i , then the optimal tip speed ratio λ of the i-th wind turbine generator set is r_opt,i for:

[0021] λ r_opt,i =f i (C pm,i ,β i ),

[0022] The optimal speed value ω of the i-th wind turbine r_opt,i for:

[0023]

[0024] Among them, R i is the blade radius of the i-th wind turbine.

[0025] S3. Determine the wind turbine generator set's standby power, the wind turbine generator set's reference speed value, and the wind power station's total standby power under reduced power operation according to the wind turbine generator set's optimal speed value and the standby power coefficient.

[0026] S3-1, the standby power P of the i-th wind turbine generator set under reduced power operation w_bak,i The calculation is done using the following formula:

[0027] P w_bak,i =P w,i *k bak,i ,

[0028] where k bak,i is the reserve power coefficient of the i-th wind turbine generator set under reduced power operation.

[0029] S3-2, reference speed value ω of the i-th wind turbine generator set under reduced power operation r_ref,i The calculation is performed using the following steps:

[0030] S3-2-1. Determine the output power P of the i-th wind turbine generator set under reduced power operation w_out,i :

[0031] P w_out,i =P w,i -P w_bak,i ,

[0032] S3-2-2. Determine the wind energy conversion efficiency coefficient C of the i-th wind turbine generator set under reduced power operation p_out,i :

[0033]

[0034] S3-2-3. Determine the tip speed ratio λ of the i-th wind turbine generator set under reduced power operation i_out :

[0035] λ i_out =f i (C p_out,i ,β i_out ),

[0036] Among them, β i_out is the pitch angle of the i-th wind turbine generator set under reduced power operation.

[0037] S3-2-4. Determine the reference speed value ω of the i-th wind turbine generator set under reduced power operation r_ref,i :

[0038]

[0039] S3-3. Total standby power of wind power station under reduced power operation P w_bak for:

[0040]

[0041] S4. Determine the frequency regulation power requirement of the wind power station based on the measured value of the power system frequency and the upper and lower limits of the frequency adjustment.

[0042] Wind power station frequency regulation power requirement ΔP w for:

[0043]

[0044] Where, f is the measured value of the power system frequency, f N,up and f N,low They are the upper and lower limits of frequency adjustment respectively (generally determined according to relevant rules and standards in my country: for example, the Power Supply Business Rules stipulate that for power systems with installed capacity of 3 million kilowatts and above, the upper and lower limits of frequency adjustment are 50.2 and 49.8 respectively; for power systems with installed capacity below 3 million kilowatts, the upper and lower limits of frequency adjustment are 50.5 and 49.5 respectively). When the measured frequency value of the power system is between the upper and lower limits of frequency adjustment, the wind power station does not respond to frequency adjustment, k up and k down They are respectively the proportional coefficient for adjusting the frequency up and the proportional coefficient for adjusting the frequency down. <f N,low When the total power generation of the power system is less than the total load power, in order to maintain the frequency within the lower limit of the frequency adjustment, the wind power station needs to enter the upward frequency adjustment mode and increase the output power of the wind power station ΔP w ; When f>f N,upWhen the total power generation of the power system is greater than the total load power, in order to maintain the frequency within the upper limit of the frequency adjustment, the wind power station needs to enter the downward frequency adjustment mode to reduce the output power of the wind power station ΔP w .

[0045] S5. In the upward frequency regulation mode of the wind power station, the standby power of the wind turbine generator set, the reference speed value of the wind turbine generator set and the total standby power of the wind power station are determined according to the frequency regulation demand power of the wind power station under the upward frequency regulation operation.

[0046] S5-1. In the upward frequency regulation mode of the wind power station, if the total reserve power of the wind power station P is reduced in power operation w_bak Greater than or equal to the wind power station frequency regulation power demand ΔP w , then the wind power station can fully meet the upward frequency regulation requirements, and the completed upward frequency regulation power value is ΔP w ; If the total reserve power of the wind power station under power reduction operation is P w_bak Less than the wind power station frequency regulation power requirement ΔP w , the wind power station cannot fully meet the upward frequency regulation requirements, and the completed upward frequency regulation power value is P w_bak , the unfinished up-frequency modulation power value is |ΔP w -P w_bak |.

[0047] S5-2. Construct a database of wind turbine generator sets to be dispatched under reduced power operation for upward frequency regulation according to the upward frequency regulation scheduling priority.

[0048] Assign the wind turbines belonging to the wind power station the upward frequency regulation scheduling priority PR i , and adjust the frequency upward according to the priority PR i The database DB1 of wind turbine generators to be dispatched under reduced power operation for upward frequency regulation is constructed by sorting from small to large. The database structure is shown in the following table:

[0049]

[0050] Among them, s i To increase the frequency of operation, press the priority PR i The wind turbine generator set number after sorting from small to large, the wind turbine generator set upward frequency regulation priority PR i Satisfaction: PR i ≤PR i+1 , P.R. i The smaller the value, the higher the priority of upward frequency modulation scheduling. w_bak,si For reduced power operation, i The standby power of wind turbine generator sets, ω r_ref,si For reduced power operation, i Reference speed value of wind turbine generator set.

[0051] S5-3, according to the database DB1 of wind turbine generators to be dispatched under reduced power operation for upward frequency regulation, ΔP w Allocate to each wind turbine.

[0052] First determine the critical upward frequency regulation wind turbine generator set number I:

[0053] (1) If the wind power station can fully meet the upward frequency regulation requirements, I is calculated using the following formula:

[0054] I

[0055]

[0056] The wind power station is assigned to the s i The power required for the upward frequency regulation of the wind turbine generator set ΔP w,si for:

[0057]

[0058] Wherein, j is an integer ranging from 1 to (I-1).

[0059] Upward FM operation next s i Reserve power P′ of wind turbine generator set w_bak,si for:

[0060]

[0061] Upward FM operation next s i Reference speed value ω′ of wind turbine generator set r_ref,si for:

[0062]

[0063] Among them, the standby power (P w_bak,si -ΔP w,si ) corresponds to the wind turbine generator speed value ω * The calculation process is as follows:

[0064] First calculate the sth i Wind energy conversion efficiency coefficient C of wind turbine generator set p,si :

[0065]

[0066] Among them, P w,si , A si , ρ si and v eq,si Respectively i The output power measurement value of the wind turbine generator set, iThe area swept by the blades of the wind turbine generator set, i The air density at the wind turbine and the i Equivalent wind speed of wind turbine generator set.

[0067] Then calculate the sth i Tip speed ratio of wind turbine generator set λ si :

[0068] λ si =f si (C p,si ,β si ),

[0069] Among them, β si Indicates the s i The pitch angle of the wind turbine.

[0070] Therefore, the standby power (P w_bak,si -ΔP w,si ) corresponds to the wind turbine generator speed value ω * for:

[0071]

[0072] Among them, R si For the s i The blade radius of a wind turbine.

[0073] PR by priority i The wind turbine dispatching database DB1_up under upward frequency regulation operation is constructed by sorting from small to large. The database structure is shown in the following table:

[0074]

[0075] Among them, ω r_opt,si For the s i The optimal speed value of wind turbine generator set.

[0076] The total reserve power of the wind power station under the upward frequency regulation operation when the wind power station can fully complete the upward frequency regulation demand for:

[0077]

[0078] (2) When the wind power station cannot fully meet the upward frequency regulation requirements, the structure of the wind turbine generator group dispatching database DB1_up' under the upward frequency regulation operation is shown in the following table:

[0079]

[0080] The total reserve power P′ of the wind power station under the upward frequency regulation operation when the wind power station cannot fully complete the upward frequency regulation demandbak_2 for:

[0081]

[0082] according to and The power dispatching agency allocates the new power system upward frequency regulation task among wind power stations. A value of 0 indicates that the wind power station could not fully meet the upward frequency regulation requirements during the last frequency regulation task. Currently, the wind power station has no upward frequency regulation reserve power and will not participate in the allocation of new power system upward frequency regulation tasks.

[0083] S6. In the downward frequency regulation mode of the wind power station, the reserve power of the wind turbine generator set, the reference speed value of the wind turbine generator set and the total reserve power of the wind power station are determined according to the frequency regulation demand power of the wind power station under the downward frequency regulation operation.

[0084] S6-1. In the wind power station downward frequency regulation mode, if the wind power station total reserve power P is reduced in power operation w_bak and the wind power station frequency regulation power demand ΔP w The sum is less than or equal to the maximum value P of the total standby power of the wind power station under reduced power operation w_bak,max , then the wind power station can fully meet the downward frequency regulation requirements, and the completed downward frequency regulation power value is ΔP w ; If the total reserve power of the wind power station under power reduction operation is P w_bak and the wind power station frequency regulation power demand ΔP w The sum is greater than the maximum value P of the total standby power of the wind power station under reduced power operation w_bak,max , the wind power station cannot fully meet the downward frequency regulation requirements, and the completed downward frequency regulation power value is ΔP w , the unfinished down-frequency modulation power value is |P w_bak,max -ΔP w |.

[0085] S6-2. In the downward frequency regulation mode of the wind power station, a database of wind turbine generator sets to be dispatched under reduced power operation for downward frequency regulation is constructed according to the downward frequency regulation scheduling priority.

[0086] Assign the wind turbines belonging to the wind power station a downward frequency regulation priority PR′ i , and follow the downward frequency scheduling priority PR′ i The database DB2 of wind turbine generators to be dispatched under power reduction operation for downward frequency regulation is constructed by sorting from small to large. The database structure is shown in the following table:

[0087]

[0088] Among them, l i To down-shift the frequency, press the priority PR′ iThe order of wind turbine generator sets after sorting from small to large, the priority PR′ of wind turbine generator set for downward frequency regulation i Satisfaction: PR′ i ≤PR′ i+1 , PR′ i The smaller the value, the higher the priority of downward frequency modulation scheduling. w_bak,li For the first i The standby power of wind turbine generator sets, ω r_ref,li For the first i Reference speed value of wind turbine generator set.

[0089] S6-3, for downward frequency regulation, the database DB2 of wind turbine generators to be dispatched under power reduction operation is used to sort ΔP in ascending order of priority. w Allocate to each wind turbine.

[0090] First, determine the critical downward frequency regulation wind turbine generator set number I′:

[0091] (1) When the wind power station can fully meet the downward frequency regulation requirements, I′ is calculated using the following formula:

[0092] minI′

[0093]

[0094] Among them, P w_bak,li,max For the first i The maximum standby power of the wind turbine generator set and the maximum total standby power of the wind power station under reduced power operation P w_bak,max equal The wind power station is assigned to the first i The power required for the downward frequency regulation of the wind turbine generator set ΔP w,li for:

[0095]

[0096] Downward frequency operation i Reserve power P′ of wind turbine generator set w_bak,li for:

[0097]

[0098] Downward frequency operation i Reference speed value ω′ of wind turbine generator set r_ref,li for:

[0099]

[0100] Among them, the standby power P w_bak,li,max The corresponding wind turbine speed value ωr_max,li The calculation process is as follows:

[0101] First calculate the lth i Wind energy conversion efficiency coefficient C of wind turbine generator set p,li :

[0102]

[0103] Among them, P w,li , A li , ρ li and v eq,li The first i The output power measurement value of the wind turbine generator set, the l i The area swept by the blades of the wind turbine generator set, the area swept by the blades of the wind turbine generator set i The air density at the wind turbine and the l i Equivalent wind speed of wind turbine generator set.

[0104] Then calculate the lth i Tip speed ratio of wind turbine generator set λ li :

[0105] λ li =f li (C p,li ,β li ),

[0106] Among them, β li Indicates the first i The pitch angle of the wind turbine.

[0107] Therefore, the reserve power P w_bak,li,max The corresponding wind turbine speed value ω r_max,li for:

[0108]

[0109] Among them, R li For the first i Radius of blades of wind turbines. Reserve power The corresponding wind turbine speed value is ω * ′.

[0110] By priority PR′ i The wind turbine dispatching database DB2_down is constructed by sorting from small to large. The database structure is shown in the following table:

[0111]

[0112] The total reserve power of the wind power station when the wind power station can fully complete the downward frequency regulation operation under the condition of downward frequency regulation demand for:

[0113] P″ w_bak_1 =P w_bak +ΔP w .

[0114] (2) In the case where the wind power station cannot fully meet the downward frequency regulation requirements, the structure of the wind turbine generator group dispatching database DB2_down' under the downward frequency regulation operation is shown in the following table:

[0115]

[0116] The total reserve power P″ of the wind power station under the downward frequency regulation operation when the wind power station cannot fully complete the downward frequency regulation demand w_bak_2 for:

[0117]

[0118] According to P″ w_bak_1 and P″ w_bak_2 The power dispatching agency allocates the new power system frequency regulation task among wind power stations. Obviously, P″ w_bak_2 for It means that the wind power station could not fully meet the downward frequency regulation requirements during the last downward frequency regulation task. Currently, the wind power station has no reserve power for downward frequency regulation and will not participate in the allocation of new power system downward frequency regulation tasks.

[0119] S7. Determine the speed deviation according to the reference speed value of the wind turbine generator set under upward and downward frequency modulation operation and the speed measurement value of the wind turbine generator set, and generate a power reference value for rotor-side inverter control through speed control.

[0120] S7-1, in the upward frequency modulation operation, set the s i The speed deviation of the wind turbine generator set is Δω r,si , then

[0121] Δω r,si =ω r,si -ω′ r_ref,si ,

[0122] Among them, ω r,si For the s i The measured value of the speed of wind turbine generator set.

[0123] No. i The power reference value for rotor-side inverter control of a wind turbine generator set is:

[0124]

[0125] Among them, K P,si and T P,siRespectively i Proportional coefficient and integral coefficient of wind turbine speed control.

[0126] S7-2, in the downward frequency modulation operation, set the first i The speed deviation of the wind turbine generator set is Δω r,li , then

[0127] Δω r,li =ω r,li -ω′ r_ref,li

[0128] Among them, ω r,li For the first i The measured value of the speed of wind turbine generator set.

[0129] No.1 i The power reference value for rotor-side inverter control of a wind turbine generator set is:

[0130]

[0131] Among them, K P,li and T P,li The first i Proportional coefficient and integral coefficient of wind turbine speed control;

[0132] Regardless of whether it is upward frequency regulation operation or downward frequency regulation operation, the power reference value used for rotor-side inverter control can be determined based on the speed deviation and the proportional coefficient and integral coefficient of the wind turbine speed control, so that the wind turbine can operate according to this power reference value, realizing flexible control of the wind power station under the conditions that the power system frequency measurement value and the upper and lower limits of the frequency adjustment are known.

[0133] The present invention also provides a wind power station flexible control device for a power system with a high proportion of new energy, including a basic data extraction module, a wind generator set power reduction operation module, a wind generator set frequency regulation operation module, a wind generator set speed control module, and a system output module;

[0134] The basic data extraction module is used to obtain the status data of the wind turbine generator set belonging to the wind power station, including the output power measurement value of the wind turbine generator set, the speed measurement value of the wind turbine generator set, and the pitch angle measurement value;

[0135] The wind turbine generator set power reduction operation module is used to determine the wind turbine generator set backup power, the wind turbine generator set reference speed value and the total backup power of the wind power station under power reduction operation according to the wind turbine generator set optimal speed value and the backup power coefficient;

[0136] The wind turbine generator set frequency regulation operation module is used for: 1. determining the wind power station frequency regulation demand power according to the power system frequency measurement value and the upper and lower limits of the frequency adjustment; 2. determining the wind turbine generator set standby power, wind turbine generator set reference speed value and wind power station total standby power under upward frequency regulation operation according to the wind power station frequency regulation demand power in the wind power station upward frequency regulation mode; 3. determining the wind turbine generator set standby power, wind turbine generator set reference speed value and wind power station total standby power under downward frequency regulation operation according to the wind power station frequency regulation demand power in the wind power station downward frequency regulation mode.

[0137] The wind turbine generator set speed control module is used to: 1. determine the speed deviation based on the wind turbine generator set reference speed value and the wind turbine generator set speed measurement value under upward and downward frequency modulation operation; 2. determine the power reference value for rotor side inverter control based on the speed deviation and the proportional coefficient and integral coefficient of the wind turbine generator speed control.

[0138] The system output module is used to output the status data of the wind generator set, the power reduction operation data of the wind generator set, the frequency regulation operation data of the wind generator set, and the speed control data of the wind generator set according to the comprehensive control needs of the wind power station.

[0139] Each module in the above-mentioned flexible control device for a wind power station in a power system with a high proportion of renewable energy can be fully or partially implemented through software, hardware and a combination thereof.

[0140] The above modules may be embedded in or independent of a processor in a computer device in the form of hardware, or may be stored in a memory in a computer device in the form of software, so that the processor can call and execute operations corresponding to the above modules.

[0141] Compared with the prior art, the present invention has the following beneficial effects:

[0142] The present invention provides a method and device for flexible control of wind power stations in power systems with a high proportion of new energy. First, according to the state data of the wind generator set, the optimal speed value of the wind generator set and the reserve power coefficient, the reserve power of the wind generator set under reduced power operation, the reference speed value of the wind generator set and the total reserve power of the wind power station are determined, so that the wind generator set operates at a predetermined power point below the maximum power point, so that the wind power station has a certain reserve capacity; then, according to the frequency regulation demand power of the wind power station and the frequency regulation priority of the wind generator set, the reserve power of the wind generator set under frequency regulation operation, the reference speed value of the wind generator set and the total reserve power of the wind power station are determined, so that the wind generator set can respond to the frequency regulation demand of power dispatch according to the frequency regulation priority, so that the wind power station has orderly frequency regulation capabilities. This method provides an effective method and means for the dispatch of wind power stations in new power systems with a high proportion of new energy, and helps to solve the problem that the volatility and randomness of new energy power generation in new power systems make the power system difficult to control. The beneficial effects of the present invention are remarkable and prominent, which are embodied in the following aspects: first, it breaks through the restriction of maximum power tracking control of wind turbine generator sets, and proposes that wind turbine generator sets may not operate at the maximum power point, but at a predetermined power point below the maximum power point, thereby storing a certain capacity of standby power that can be used for the frequency regulation demand of the power system while ensuring high efficiency, thereby enhancing the flexibility of wind power station output; second, the standby power of wind turbine generator sets, the reference speed value of wind turbine generator sets and the total standby power of wind power station under frequency regulation operation are determined according to the frequency regulation demand power of wind power station and the frequency regulation priority of wind turbine generator sets, and a power reference value for rotor-side inverter control is generated through speed control, so that the wind power station has the ability to respond to frequency in real time and cope with unexpected load fluctuations, and the design of frequency regulation priority enables wind turbine generator sets to participate in frequency regulation in an orderly manner (such as wind turbines that have been in operation for too long). The wind turbines under maintenance are given lower priority, and the wind turbines under maintenance are not given priority, etc.). In this way, the reliability of wind turbines in responding to frequency modulation is improved, the adverse effects of volatility and randomness of renewable energy power generation in new power systems are reduced, and the safety and stability control level of new power systems is improved; thirdly, for new power systems with a higher proportion of renewable energy, especially new power systems with a higher proportion of wind power, the beneficial effects of the present invention are more prominent. This is because the higher the proportion of renewable energy, the more obvious the volatility and randomness of renewable energy power generation, and the more difficult it is to regulate the power system using conventional methods. The new power system with a higher proportion of wind power allows more wind turbines to operate at reduced power, and the ability to resist volatility and randomness of renewable energy power generation is stronger. Therefore, the use of the present invention is more helpful to improve the safety and stability control level of new power systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0143] Figure 1 It is a flow chart of the method for flexible control of wind power stations in a power system with a high proportion of renewable energy in the present invention;

[0144] Figure 2 It is a mapping relationship diagram of blade tip speed ratio, pitch angle, and wind energy conversion efficiency coefficient in the present invention;

[0145] Figure 3 It is a control structure diagram of power reduction operation and frequency modulation operation of a wind turbine generator in the present invention;

[0146] Figure 4 It is a system structure diagram of a flexible control device for a wind power station in an electric power system with a high proportion of renewable energy in the present invention. DETAILED DESCRIPTION

[0147] The present invention will be further described below in conjunction with specific implementations and drawings.

[0148] Figure 1 This is a flow chart of the flexible control method of a wind power station in a power system with a high proportion of renewable energy in the present invention. The process is as follows:

[0149] S1. Obtaining status data of the wind turbine generator set belonging to the wind power station, including the output power measurement value of the wind turbine generator set, the speed measurement value of the wind turbine generator set, and the pitch angle measurement value;

[0150] S2. Determine the optimal speed value of the wind turbine generator set according to the status data of the wind turbine generator set belonging to the wind power station;

[0151] S3, determining the wind turbine generator set standby power, the wind turbine generator set reference speed value and the total standby power of the wind power station under reduced power operation according to the wind turbine generator set optimal speed value and the standby power coefficient;

[0152] S4. Determine the frequency regulation power requirement of the wind power station according to the measured value of the power system frequency and the upper and lower limits of the frequency adjustment;

[0153] S5. Determine the standby power of the wind turbine generator set, the reference speed value of the wind turbine generator set and the total standby power of the wind power station under the upward frequency regulation operation according to the frequency regulation demand power of the wind power station in the upward frequency regulation mode of the wind power station;

[0154] S6. Determine the reserve power of the wind turbine generator set, the reference speed value of the wind turbine generator set and the total reserve power of the wind power station under the downward frequency regulation operation according to the frequency regulation demand power of the wind power station in the downward frequency regulation mode of the wind power station;

[0155] S7. Determine the speed deviation according to the reference speed value of the wind turbine generator set in the upward (downward) frequency modulation operation and the speed measurement value of the wind turbine generator set, and generate a power reference value for controlling the rotor-side frequency converter through speed control.

[0156] Figure 2 It is a mapping relationship diagram of the blade tip speed ratio, pitch angle, and wind energy conversion efficiency coefficient in the present invention.

[0157] Since the output power of wind turbines is closely related to air density, the area swept by the blades, wind speed, and wind energy conversion efficiency of wind turbines, we have:

[0158]

[0159] Among them, P w,i is the output power measurement value of the i-th wind turbine generator set, A i is the area swept by the blades of the i-th wind turbine, C p,i is the wind energy conversion efficiency coefficient of the i-th wind turbine generator set, which is the tip speed ratio λ of the i-th wind turbine generator set i and pitch angle β i The nonlinear function, ρ i is the air density at the i-th wind turbine, v eq,i is the equivalent wind speed of the i-th wind turbine.

[0160] Assume that the pitch angle of the i-th wind turbine is β i , the tip speed ratio is λ i , then the wind energy conversion efficiency coefficient C of the i-th wind turbine generator set is p,i is the pitch angle β i and tip speed ratio λ i The function of is mainly determined by the design of the blade and can be approximated by the following formula:

[0161]

[0162] exist Figure 2 In the figure, β and i =0°, β i =5°, β i =10° and β i =15° when the wind energy conversion efficiency coefficient C of the i-th wind turbine generator set p,i With tip speed ratio λ i The change law of. As can be seen from the figure, for a given pitch angle of β i , there is always a tip speed ratio λ i The value of wind energy conversion efficiency coefficient C p,i can reach the maximum value, that is, there is always a tip speed ratio λ i The value of makes the wind energy conversion efficiency of the i-th wind turbine generator set maximum. This also means that for the changing wind speed, the rotor speed of the i-th wind turbine generator set must be variable to make the tip speed ratio λ i The value of satisfies the wind energy conversion efficiency coefficient C p,i Take the maximum value.

[0163] However, since the measurement of wind speed is affected by blade height, blade obstruction and tower, the wind speed signal obtained by the anemometer is difficult to reflect the wind speed felt by the wind turbine blades. Therefore, the wind turbine control does not use wind speed as the input control signal, but uses the wind turbine speed as the input control signal. That is, the reference speed is obtained through the output power of the wind turbine, and the speed deviation is obtained by comparing the reference speed with the actual speed, thereby forming a feedback control system based on speed control.

[0164] The wind energy conversion efficiency coefficient C of the i-th wind turbine generator set p,i for:

[0165]

[0166] Since the wind energy conversion efficiency coefficient of a wind turbine is a nonlinear function of the tip speed ratio and the pitch angle, the tip speed ratio λ of the i-th wind turbine is i for:

[0167] λ i =f i (C p,i ,β i ),

[0168] Among them, f i (·,·) represents the wind energy conversion efficiency coefficient C of the i-th wind turbine p,i and pitch angle β i Tip speed ratio λ i The mapping relationship.

[0169] Assume that the wind energy conversion efficiency coefficient C of the i-th wind turbine is p,i The maximum value is C pm,i , then the optimal tip speed ratio λ of the i-th wind turbine generator set is r_opt,i for:

[0170] λ r_opt,i =f i (C pm,i ,β i )

[0171] The optimal speed value ω of the i-th wind turbine r_opt,i for:

[0172]

[0173] Among them, R i is the blade radius of the i-th wind turbine.

[0174] When the i-th wind turbine generator set is at the optimal speed value ω r_opt,i During operation, the wind energy conversion efficiency coefficient C of the i-th wind turbine generator set p,i Take the maximum value Cpm,i , the i-th wind turbine achieves maximum wind energy capture. At this time, the output power is the maximum power that can be generated under the wind speed, and the backup power provided is 0.

[0175] When the i-th wind turbine generator set is in reduced power operation, the output power P of the i-th wind turbine generator set under reduced power operation is w_out,i , P w_out,i The calculation formula is:

[0176] P w_out,i =P w,i -P w_bak,i ,

[0177] Wind energy conversion efficiency coefficient C of the i-th wind turbine generator set under reduced power operation p_out,i The calculation formula is:

[0178]

[0179] Tip speed ratio λ of the i-th wind turbine under reduced power operation i_out The calculation formula is:

[0180] λ i_out =f i (C p_out,i ,β i_out ),

[0181] Among them, β i_out is the pitch angle of the i-th wind turbine generator set under reduced power operation.

[0182] Reference speed value ω of the i-th wind turbine generator set under reduced power operation r_ref,i The calculation formula is:

[0183]

[0184] When the i-th wind turbine generator set rotates at the reference speed value ω r_ref,i During operation, the output power of the i-th wind turbine generator set is P w_out,i , the backup power provided is P w_bak,i .

[0185] Figure 3 is a control structure diagram of the wind turbine generator power reduction operation and frequency modulation operation in the present invention. Among them, situation (1) represents the upward frequency modulation mode, at this time f <f N,low , that is, the total power generation of the power system is less than the total load power. To maintain the frequency within the lower limit of the frequency adjustment f N,low The wind power station needs to enter the upward frequency regulation mode to increase the wind power station output power ΔP w To increase the system frequency; case (2) represents the downward frequency modulation mode, when f>f N,up, that is, the total power generation of the power system is greater than the total load power. To maintain the frequency within the upper limit of the frequency adjustment f N,up The wind power station needs to enter the downward frequency regulation mode to reduce the wind power station output power ΔP w To reduce the system frequency.

[0186] For case (1), the sth i The measured output power of the wind turbine generator set is P w,si , allocated to the sth wind power station i The power required for the upward frequency regulation of the wind turbine generator set ΔP w,si for:

[0187]

[0188] Where j is an integer ranging from 1 to (I-1). I is calculated using the following formula:

[0189] I

[0190]

[0191] Upward FM operation next s i Reserve power P′ of wind turbine generator set w_bak,si for:

[0192]

[0193] Upward FM operation next s i Reference speed value ω′ of wind turbine generator set r_ref,si for:

[0194]

[0195] Among them, the standby power (P w_bak,si -ΔP w,si ) corresponds to the wind turbine generator speed value ω * The calculation process is as follows: First, calculate the sth i Wind energy conversion efficiency coefficient C of wind turbine generator set p,si :

[0196]

[0197] Among them, P w,si , A si , ρ si and v eq,si Respectively i The output power measurement value of the wind turbine generator set, i The area swept by the blades of the wind turbine generator set, i The air density at the wind turbine and the iEquivalent wind speed of wind turbine generator set.

[0198] Then calculate the sth i Tip speed ratio of wind turbine generator set λ si :

[0199] λ si =f si (C p,si ,β si ),

[0200] Among them, f si (·,·) indicates the sth i Wind energy conversion efficiency coefficient C of wind turbine generator set p,si and pitch angle β si Tip speed ratio λ si The mapping relationship.

[0201] Therefore, the reserve power P w_bak,si -ΔP w,si The corresponding wind turbine speed value ω * for:

[0202]

[0203] Among them, R si For the s i The blade radius of a wind turbine.

[0204] In upward frequency modulation operation, set the s i The speed deviation of the wind turbine generator set is Δω r,si , then

[0205] Δω r,si =ω r,si -ω′ r_ref,si ,

[0206] Among them, ω r,si For the s i The measured value of the speed of wind turbine generator set.

[0207] No. i The power reference value for rotor-side inverter control of a wind turbine generator set is:

[0208]

[0209] Among them, K P,si and T P,si Respectively i Proportional coefficient and integral coefficient of wind turbine speed control.

[0210] For case (2), the wind power station is assigned to the lth iThe power required for the downward frequency regulation of the wind turbine generator set ΔP w,li for:

[0211]

[0212] I' is calculated using the following formula:

[0213] minI′

[0214]

[0215] Among them, P w_bak,li,max For the first i The maximum standby power of wind turbine generator set. The maximum total standby power of wind power station under reduced power operation P w_bak,max equal

[0216] Downward frequency operation i Reserve power P′ of wind turbine generator set w_bak,li for:

[0217]

[0218] Downward frequency operation i Reference speed value ω′ of wind turbine generator set r_ref,li for:

[0219]

[0220] Among them, the standby power P w_bak,li,max The corresponding wind turbine speed value ω r_max,li The calculation process is as follows: First, calculate the lth i Wind energy conversion efficiency coefficient C of wind turbine generator set p,li :

[0221]

[0222] Among them, P w,li , A li , ρ li and v eq,li The first i The output power measurement value of the wind turbine generator set, the l i The area swept by the blades of the wind turbine generator set, the area swept by the blades of the wind turbine generator set i The air density at the wind turbine and the l i Equivalent wind speed of wind turbine generator set.

[0223] Then calculate the lth i Tip speed ratio of wind turbine generator set λ li :

[0224] λ li =f li (C p,li ,β li ),

[0225] Among them, f li (·,·) indicates the first i Wind energy conversion efficiency coefficient C of wind turbine generator set p,li and pitch angle β li Tip speed ratio λ li The mapping relationship.

[0226] Therefore, the reserve power P w_bak,li,max The corresponding wind turbine speed value ω r_max,li for:

[0227]

[0228] Among them, R li For the first i Radius of blades of wind turbines. Reserve power The corresponding wind turbine speed value is ω * ′.

[0229] In the downward frequency modulation operation, set the first i The speed deviation of the wind turbine generator set is Δω r,li , then

[0230] Δω r,li =ω r,li -ω′ r_ref,li

[0231] Among them, ω r,li For the first i The measured value of the speed of wind turbine generator set.

[0232] No.1 i The power reference value for rotor-side inverter control of a wind turbine generator set is:

[0233]

[0234] Among them, K P,li and T P,li The first i Proportional coefficient and integral coefficient of wind turbine speed control.

[0235] Figure 4It is a system structure diagram of the flexible control device of a wind power station in the power system with a high proportion of new energy in the present invention. The system consists of a basic data extraction module, a wind turbine power reduction operation module, a wind turbine frequency regulation operation module, a wind turbine speed control module, and a system output module. Among them, the basic data extraction module obtains the status data of the wind turbines belonging to the wind power station from the wind power station dispatching and control system, such as the wind turbine output power measurement value, the wind turbine speed measurement value, the pitch angle measurement value, etc., which are used for the closed-loop control of the wind turbine power reduction operation or frequency regulation operation; the wind turbine power reduction operation module is used to determine the wind turbine backup power, the wind turbine reference speed value and the total backup power of the wind power station under power reduction operation according to the optimal speed value and the backup power coefficient of the wind turbine. In this case, the wind turbine reserves a certain amount of backup power; the wind turbine frequency regulation operation module is used to: ① determine the wind power station frequency regulation demand power according to the power system frequency measurement value and the upper and lower limits of the frequency adjustment; ② determine the wind power station frequency regulation demand power under the upward frequency regulation operation according to the wind power station frequency regulation demand power in the upward frequency regulation mode The system output module is used to output the status data of the wind turbine, the power reduction operation data of the wind turbine, the frequency regulation operation data of the wind turbine, and the speed control data of the wind turbine according to the needs of the wind power station for comprehensive control of the wind power station.

Claims

1. A method for flexible control of wind power stations in a power system with a high proportion of renewable energy, characterized in that: The method is divided into the following steps: S1. Obtaining status data of the wind turbine generator set belonging to the wind power station, including the output power measurement value of the wind turbine generator set, the speed measurement value of the wind turbine generator set, and the pitch angle measurement value; Assume that the number of wind turbines in a wind power station is N, the sequence number of the wind turbine is i, and the state data set Gen_Set of the i-th wind turbine is i for: Gen_Set i ={P w,i ,oh r,i ,b i |i∈(1,2,…,N)}, Among them, P w,i is the output power measurement value of the i-th wind turbine generator set, ω r,i is the measured speed value of the i-th wind turbine generator set, β i is the measured value of the pitch angle of the i-th wind turbine generator set; S2, determining the optimal speed value of the wind turbine generator set according to the status data of the wind turbine generator set belonging to the wind power station obtained in S1; Since the output power of wind turbines is closely related to air density, blade swept area, equivalent wind speed, and wind energy conversion efficiency of wind turbines, we have: Among them, A i is the area swept by the blades of the i-th wind turbine, C p,i is the wind energy conversion efficiency coefficient of the i-th wind turbine generator set, which is the tip speed ratio λ of the i-th wind turbine generator set i and pitch angle β i The nonlinear function, ρ i is the air density at the i-th wind turbine, v eq,i is the equivalent wind speed of the i-th wind turbine generator set; The wind energy conversion efficiency coefficient C of the i-th wind turbine generator set is p,i for: Since the wind energy conversion efficiency coefficient C of the wind turbine p,i is the tip speed ratio λ i and pitch angle β i is a nonlinear function, so the tip speed ratio λ of the i-th wind turbine i for: l i =f i (C p,i ,b i ), Among them, f i (·,·) represents the wind energy conversion efficiency coefficient C of the i-th wind turbine p,i and pitch angle β i Tip speed ratio λ i The mapping relationship of Assume that the wind energy conversion efficiency coefficient C of the i-th wind turbine is p,i The maximum value is C pm,i , then the optimal tip speed ratio λ of the i-th wind turbine generator set is r_opt,i for: l r_opt,i =f i (C pm,i ,b i ), The optimal speed value ω of the i-th wind turbine r_opt,i for: Among them, R i is the blade radius of the i-th wind turbine; S3, determining the wind turbine generator set standby power, the wind turbine generator set reference speed value and the total standby power of the wind power station under reduced power operation according to the wind turbine generator set optimal speed value and the standby power coefficient; S3-1, the standby power P of the i-th wind turbine generator set under reduced power operation w_bak,i The calculation is done using the following formula: P w_bak，i =P w，i *k bak，i , where k bak，i is the reserve power coefficient of the i-th wind turbine generator set under reduced power operation; S3-2, reference speed value ω of the i-th wind turbine generator set under reduced power operation r_ref，i The calculation is performed using the following steps: S3-2-1. Determine the output power P of the i-th wind turbine generator set under reduced power operation w_out，i : P w _ out，i =P w，i -P w_bak，i , S3-2-2. Determine the wind energy conversion efficiency coefficient C of the i-th wind turbine generator set under reduced power operation p_out，i : S3-2-3. Determine the tip speed ratio λ of the i-th wind turbine generator set under reduced power operation i_out : l i_out =f i (C p_out，i ,b i_out ), Among them, β i_out is the pitch angle of the i-th wind turbine generator set under reduced power operation; S3-2-4. Determine the reference speed value ω of the i-th wind turbine generator set under reduced power operation r_ref,i : S3-3. Total standby power of wind power station under reduced power operation P w_bak for: S4. Determine the frequency regulation power requirement of the wind power station according to the measured value of the power system frequency and the upper and lower limits of the frequency adjustment; Wind power station frequency regulation power requirement ΔP w for: Where, f is the measured value of the power system frequency, f N，up and f N，low are the upper and lower limits of frequency adjustment respectively. When the measured frequency value of the power system is between the upper and lower limits of frequency adjustment, the wind power station does not respond to frequency adjustment. up and k down They are respectively the proportional coefficient for adjusting the frequency up and the proportional coefficient for adjusting the frequency down; when f<f N，low When the total power generation of the power system is less than the total load power, in order to maintain the frequency within the lower limit of the frequency adjustment, the wind power station needs to enter the upward frequency adjustment mode and increase the output power of the wind power station ΔP w ; When f>f N，up When the total power generation of the power system is greater than the total load power, in order to maintain the frequency within the upper limit of the frequency adjustment, the wind power station needs to enter the downward frequency adjustment mode to reduce the output power of the wind power station ΔP w ; S5. Determine the standby power of the wind turbine generator set, the reference speed value of the wind turbine generator set and the total standby power of the wind power station under the upward frequency regulation operation according to the frequency regulation demand power of the wind power station in the upward frequency regulation mode of the wind power station; S6. Determine the reserve power of the wind turbine generator set, the reference speed value of the wind turbine generator set and the total reserve power of the wind power station under the downward frequency regulation operation according to the frequency regulation demand power of the wind power station in the downward frequency regulation mode of the wind power station; S7, determining the speed deviation according to the reference speed value of the wind turbine generator set under upward and downward frequency modulation operation and the speed measurement value of the wind turbine generator set, and generating a power reference value for rotor-side inverter control through speed control; S7-1, in upward frequency modulation operation, set the s i The speed deviation of the wind turbine generator set is Δω r，si , then Give r,si =ω r，si -ω′ r_ref,si , Among them, ω r，si For the s i The measured value of the speed of wind turbine generator set; No. i The power reference value for rotor-side inverter control of a wind turbine generator set is: Among them, K P，si and T P，si Respectively i Proportional coefficient and integral coefficient of wind turbine speed control; S7-2, in the downward frequency modulation operation, set the first i The speed deviation of the wind turbine generator set is Δω r，li , then Give r,li =ω r，li -ω′ r_ref,li Among them, ω r，li For the first i The measured value of the speed of wind turbine generator set; No.1 i The power reference value for rotor-side inverter control of a wind turbine generator set is: Among them, K P，li and T P，li The first i Proportional coefficient and integral coefficient of wind turbine speed control; Regardless of whether it is upward frequency regulation operation or downward frequency regulation operation, the power reference value used for rotor-side inverter control can be determined based on the speed deviation and the proportional coefficient and integral coefficient of the wind turbine speed control, so that the wind turbine can operate according to this power reference value, realizing flexible control of the wind power station under the conditions that the power system frequency measurement value and the upper and lower limits of the frequency adjustment are known.

2. A method for flexible control of wind power stations in a power system with a high proportion of renewable energy according to claim 1, characterized in that: The specific steps of S5 are as follows: S5-1. In the upward frequency regulation mode of the wind power station, if the total reserve power of the wind power station P is reduced in power operation w_bak Greater than or equal to the wind power station frequency regulation power demand ΔP w , then the wind power station can fully meet the upward frequency regulation requirements, and the completed upward frequency regulation power value is ΔP w ; If the total reserve power of the wind power station under power reduction operation is P w_bak Less than the wind power station frequency regulation power requirement ΔP w , the wind power station cannot fully meet the upward frequency regulation requirements, and the completed upward frequency regulation power value is P w_bak , the unfinished up-frequency modulation power value is |ΔP w -P w_bak |; S5-2, constructing a database of wind turbine generators to be dispatched under reduced power operation for upward frequency regulation according to the upward frequency regulation scheduling priority; Assign the wind turbines belonging to the wind power station the upward frequency regulation scheduling priority PR i , and adjust the frequency upward according to the priority PR i The database DB1 of wind turbine generators to be dispatched under reduced power operation for upward frequency regulation is constructed by sorting from small to large. The database structure is shown in the following table: Among them, s i To increase the frequency of operation, press the priority PR i The wind turbine generator set number after sorting from small to large, the wind turbine generator set upward frequency regulation priority PR i Satisfaction: PR i ≤PR i+1 , P.R. i The smaller the value, the higher the priority of upward frequency modulation scheduling. w_bak，si For reduced power operation, i The standby power of wind turbine generator sets, ω r_ref，si For reduced power operation, i Reference speed value of wind turbine generator set; S5-3, according to the database DB1 of wind turbine generators to be dispatched under reduced power operation for upward frequency regulation, ΔP w Allocate to each wind turbine generator set; First determine the critical upward frequency regulation wind turbine generator set number I: (1) If the wind power station can fully meet the upward frequency regulation requirements, I is calculated using the following formula: min I The wind power station is assigned to the s i The power required for the upward frequency regulation of the wind turbine generator set ΔP w，si for: Where j is an integer ranging from 1 to (I-1); Upward FM operation next s i Reserve power P′ of wind turbine generator set w_bak，si for: Upward FM operation next s i Reference speed value ω′ of wind turbine generator set r_ref,si for: Among them, the standby power (P w_bak，si -ΔP w，si ) corresponds to the wind turbine generator speed value ω * The calculation process is as follows: First calculate the sth i Wind energy conversion efficiency coefficient C of wind turbine generator set p，si : Among them, P w，si , A si , ρ si and v eq，si Respectively i The output power measurement value of the wind turbine generator set, i The area swept by the blades of the wind turbine generator set, i The air density at the wind turbine and the i Equivalent wind speed of wind turbine generator set; Then calculate the sth i Tip speed ratio of wind turbine generator set λ si : l si =f si (C p，si ,b si ), Among them, β si Indicates the s i Pitch angle of wind turbine generator set; Therefore, the standby power (P w_bak，si -ΔP w，si ) corresponds to the wind turbine generator speed value ω * for: Among them, R si For the s i Radius of blades of wind turbines; PR by priority i The wind turbine generator group dispatching database DB1_up under upward frequency regulation operation is constructed by sorting from small to large. The database structure is shown in the following table: Among them, ω r_opt,si For the s i The optimal speed value of wind turbine generator set; The total reserve power of the wind power station under the upward frequency regulation operation when the wind power station can fully complete the upward frequency regulation demand for: (2) When the wind power station cannot fully meet the upward frequency regulation requirements, the structure of the wind turbine generator group dispatching database DB1_up' under the upward frequency regulation operation is shown in the following table: Total reserve power of wind power stations under upward frequency regulation when wind power stations cannot fully complete the upward frequency regulation demand for: according to and The power dispatching agency allocates the new power system upward frequency regulation task among wind power stations. Obviously, A value of 0 indicates that the wind power station could not fully meet the upward frequency regulation requirements during the last frequency regulation task. Currently, the wind power station has no upward frequency regulation reserve power and will not participate in the allocation of new power system upward frequency regulation tasks.

3. A method for flexible control of wind power stations in a power system with a high proportion of renewable energy according to claim 1, characterized in that: The specific steps of S6 are as follows: S6-1. In the wind power station downward frequency regulation mode, if the wind power station total reserve power P is reduced in power operation w_bak and the wind power station frequency regulation power demand ΔP w The sum is less than or equal to the maximum value P of the total standby power of the wind power station under reduced power operation w_bak,max , then the wind power station can fully meet the downward frequency regulation requirements, and the completed downward frequency regulation power value is ΔP w ; If the total reserve power of the wind power station under power reduction operation is P w_bak and the wind power station frequency regulation power demand ΔP w The sum is greater than the maximum value P of the total standby power of the wind power station under reduced power operation w_bak,max , the wind power station cannot fully meet the downward frequency regulation requirements, and the completed downward frequency regulation power value is ΔP w The unfinished down-frequency modulation power value is |P w_bak，max -ΔP w |; S6-2, in the downward frequency regulation mode of the wind power station, constructing a database of wind turbine generator sets to be dispatched under reduced power operation for downward frequency regulation according to the downward frequency regulation scheduling priority; Assign the wind turbines belonging to the wind power station a downward frequency regulation priority PR′ i , and follow the downward frequency scheduling priority PR′ i The database DB2 of wind turbine generators to be dispatched under power reduction operation for downward frequency regulation is constructed by sorting from small to large. The database structure is shown in the following table: Among them, l i To down-shift the frequency, press the priority PR′ i The order of wind turbine generator sets after sorting from small to large, the priority PR′ of wind turbine generator set for downward frequency regulation i Satisfaction: PR′ i ≤PR′ i+1 , PR′ i The smaller the value, the higher the priority of downward frequency modulation scheduling. w_bak，li For the first i The standby power of wind turbine generator sets, ω r_ref，li For the first i Reference speed value of wind turbine generator set; S6-3, the database DB2 of wind turbine generators to be dispatched under power reduction operation for downward frequency regulation, in order of priority from small to large, ΔP w Allocate to each wind turbine generator set; First, determine the critical downward frequency regulation wind turbine generator set number I′: (1) When the wind power station can fully meet the downward frequency regulation requirements, I′ is calculated using the following formula: min I′ Among them, P w_bak,li,max For the first i The maximum standby power of the wind turbine generator set and the maximum total standby power of the wind power station under reduced power operation P w_bak，max equal The wind power station is assigned to the first i The power required for the downward frequency regulation of the wind turbine generator set ΔP w，li for: Downward frequency operation i Reserve power P′ of wind turbine generator set w_bak，li for: Downward frequency operation i Reference speed value ω′ of wind turbine generator set r-ref,li for: Among them, the standby power P w_bak,li,max The corresponding wind turbine speed value ω r_max,li The calculation process is as follows: First calculate the lth i Wind energy conversion efficiency coefficient C of wind turbine generator set pr，l : Among them, P w，li , A li , ρ li and v eq,li The first i The output power measurement value of the wind turbine generator set, the l i The area swept by the blades of the wind turbine generator set, the area swept by the blades of the wind turbine generator set i The air density at the wind turbine and the i Equivalent wind speed of wind turbine generator set; Then calculate the lth i Tip speed ratio of wind turbine generator set λ li : l li =f li (C p，li ,b li ), Among them, β li Indicates the first i Pitch angle of wind turbine generator set; Therefore, the reserve power P w_bak,li,max The corresponding wind turbine speed value ω r_max,li for: Among them, R li For the first i Radius of blades of wind turbine generator sets; Standby power The corresponding wind turbine speed value is ω *′ ; By priority PR′ i The wind turbine dispatching database DB2_down is constructed by sorting from small to large. The database structure is shown in the following table: The total reserve power of the wind power station when the wind power station can fully complete the downward frequency regulation operation under the condition of downward frequency regulation demand for: P″ w_bak_1 =P w_bak +ΔP w ; (2) In the case where the wind power station cannot fully meet the downward frequency regulation requirements, the structure of the wind turbine generator group dispatching database DB2_down' under the downward frequency regulation operation is shown in the following table: The total reserve power P″ of the wind power station under the downward frequency regulation operation when the wind power station cannot fully complete the downward frequency regulation demand w_bak_2 for: According to P″ w_bak_1 and P″ w_bak_2 The power dispatching agency allocates the new power system frequency regulation task among wind power stations. Obviously, P″ w_bak_2 for It means that the wind power station could not fully meet the downward frequency regulation requirements during the last downward frequency regulation task. Currently, the wind power station has no reserve power for downward frequency regulation and will not participate in the allocation of new power system downward frequency regulation tasks.

4. A method for flexible control of wind power stations in a power system with a high proportion of renewable energy according to claim 1, characterized in that: In S4, the upper and lower bounds of the frequency adjustment f N，up and f N，low According to relevant rules and standards of my country, the following is determined: For power systems with installed capacity of 3 million kilowatts and above, the upper and lower limits of frequency adjustment are 50.2Hz and 49.8Hz respectively; for power systems with installed capacity of less than 3 million kilowatts, the upper and lower limits of frequency adjustment are 50.5Hz and 49.5Hz respectively.

5. A flexible control device for a wind power station in a power system with a high proportion of new energy according to the method of any one of claims 1 to 4, characterized in that: It includes basic data extraction module, wind turbine power reduction operation module, wind turbine frequency regulation operation module, wind turbine speed control module and system output module; The basic data extraction module is used to obtain the status data of the wind turbine generator set belonging to the wind power station, including the output power measurement value of the wind turbine generator set, the speed measurement value of the wind turbine generator set, and the pitch angle measurement value; The wind turbine generator set power reduction operation module is used to determine the wind turbine generator set backup power, the wind turbine generator set reference speed value and the total backup power of the wind power station under power reduction operation according to the wind turbine generator set optimal speed value and the backup power coefficient; The wind turbine generator set frequency regulation operation module is used for:

1. Determine the frequency regulation demand power of the wind power station according to the frequency measurement value of the power system and the upper and lower limits of the frequency adjustment; 2. Determine the standby power of the wind generator set under the upward frequency regulation operation, the reference speed value of the wind generator set and the total standby power of the wind power station according to the frequency regulation demand power of the wind power station in the upward frequency regulation mode of the wind power station; 3. Determine the standby power of the wind generator set under the downward frequency regulation operation, the reference speed value of the wind generator set and the total standby power of the wind power station according to the frequency regulation demand power of the wind power station in the downward frequency regulation mode of the wind power station; The wind turbine generator speed control module is used to:

1. determine the speed deviation according to the wind turbine generator speed reference value and the wind turbine generator speed measurement value under the upward and downward frequency modulation operation; 2. Determine the power reference value for rotor-side inverter control based on the speed deviation and the proportional coefficient and integral coefficient of the wind turbine speed control; The system output module is used to output the status data of the wind generator set, the power reduction operation data of the wind generator set, the frequency regulation operation data of the wind generator set, and the speed control data of the wind generator set according to the comprehensive control needs of the wind power station.

6. A flexible control device for a wind power station in a power system with a high proportion of renewable energy according to claim 5, characterized in that: Each module in the device may be implemented in whole or in part by software, hardware or a combination thereof.

7. A flexible control device for a wind power station in a power system with a high proportion of renewable energy according to claim 5, characterized in that: Each module in the apparatus may be embedded in or independent of a processor in a computer device in the form of hardware, or may be stored in a memory in a computer device in the form of software, so that the processor can call and execute operations corresponding to each of the above modules.

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