Flywheel energy storage power station primary frequency modulation method and system

Abstract

The invention discloses a primary frequency modulation method and system for a flywheel energy storage power station, and belongs to the field of electrical engineering, and the method comprises the steps: detecting the voltage and frequency of a grid-connected point and the initial power of a PCS, and determining to carry out rotating speed balance or primary frequency modulation operation according to whether the frequency is in a dead zone or not. The frequency modulation power is preferentially distributed to the flywheel for energy storage, and wind and light participation is considered and distributed in proportion when energy is insufficient. According to the flywheel rotating speed, the safety state and the power constraint, single-machine pre-distribution power is calculated, the rotating speed at the future moment is estimated, and safety state and power out-of-limit verification is carried out. And if the power is vacant and the flywheel does not reach the maximum power, redistributing the power and repeatedly calculating until no vacant power exists or the flywheel is full of power, and finally outputting the distribution power of each unit. According to the invention, when the wind-solar storage device quickly responds to the primary frequency modulation requirement, the rotating speed and power of the flywheels in the flywheel array are optimally managed, and the safety state of the flywheel single machine is verified.

Description

Technical Field

[0001] The invention belongs to the field of electrical engineering, and mainly relates to a primary frequency modulation method and system for a flywheel energy storage power station. Background Art

[0002] As the proportion of new energy and power electronic devices in new power systems continues to increase, the power grid's demand for high-frequency frequency regulation is increasing. Compared with new energy storage such as electrochemical energy storage, flywheel energy storage has the advantages of high charging and discharging frequency, long service life, and high power generation efficiency, and is suitable for participating in the primary frequency regulation of the power grid. Flywheel energy storage has the phenomenon of self-discharge. After long-term operation, there will be speed inconsistency between single flywheel units, which will affect the overall output and control performance of the flywheel array. The flywheel unit needs to be adjusted to restore the speed to ensure the speed consistency. At the same time, the speed of the high-speed flywheel is above 10,000 rpm. Improper control will cause a flying accident, which has very serious consequences. Most of the currently operating flywheel energy storage power stations adopt a control strategy of consistent single-machine charge state or average distribution of power instructions. There is a lack of flywheel array collaborative control methods that consider factors such as flywheel speed balance and self-recovery, and flywheel safe operation constraints. Summary of the invention

[0003] In order to overcome the shortcomings of the above-mentioned prior art, the present invention provides a primary frequency regulation method and system for a flywheel energy storage power station. While the wind, solar and energy storage quickly respond to the primary frequency regulation needs, the present invention realizes the optimized management of the flywheel speed and power in the flywheel array and verifies the safety status of the single flywheel.

[0004] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0005] In a first aspect, the present invention provides a primary frequency regulation method for a flywheel energy storage power station that takes into account both speed regulation and state safety, comprising:

[0006] S1: Initialization of high-speed flywheel array parameters, including: single-machine flywheel speed ni, charge and discharge safety status Start-stop state, power constraint;

[0007] S2: Obtain the voltage, frequency, and PCS initial power of the grid connection point, and calculate the power demand ΔP in two cases based on the voltage, frequency, and PCS initial power of the grid connection point. f :First, when the frequency is in the dead zone, the flywheel speed balancing operation is performed, and the speed balancing power ΔP re ; Second, when the frequency exceeds the dead zone, a frequency modulation operation is performed, ΔP f is the primary frequency modulation power;

[0008] S3: The frequency modulation power demand ΔP fAllocate to flywheel energy storage, wind power, and photovoltaics; give priority to flywheel energy storage frequency regulation, and then allocate wind and solar frequency regulation power in proportion according to the real-time output of wind and solar;

[0009] S4: In frequency modulation power demand ΔP f After allocation, the power of the high-speed flywheel unit in response to the primary frequency modulation of the power grid is set to ΔP FESS ; According to the speed n of the high-speed flywheel energy storage unit i , safe state of charge and discharge Power constraint, calculate the pre-allocated power of a single flywheel unit;

[0010] S5: estimating the speed of each flywheel at time t+T according to the pre-allocated power;

[0011] S6: Perform safety status verification at the estimated speed of each flywheel at time t+T, and adjust the power of the flywheel energy storage unit whose safety status is less than 1;

[0012] S7: After the power is adjusted, a power over-limit check is performed and the power shortage is calculated;

[0013] S8: Determine whether the power shortage is less than the threshold value. If not, the power shortage is redistributed to the high-speed flywheel whose speed does not exceed the limit, and return to S5, and repeat until there is no frequency modulation power shortage or each flywheel energy storage unit reaches the maximum power; if it is less than, the power allocated to each unit is output.

[0014] As a further improvement of the present invention, in S2: the power demand ΔP is calculated in two cases f , specifically:

[0015]

[0016] The first case: when f min ≤f≤f max When the frequency is not required, the speed n of the flywheel energy storage system is adjusted to the reference value. When the frequency modulation dead zone is reached and the flywheel speed is close to the maximum and minimum speed values, the balanced power ΔP is used. re Balance the speed of the flywheel energy storage system to the reference value

[0017] The second case: When the frequency f exceeds the dead zone, a frequency modulation operation is required, using the power demand ΔP f Perform a frequency modulation operation, where δ% is the frequency modulation difference rate of the new energy station, P N is the rated power of the new energy station, f is the real-time frequency of the grid-connected point, and m is the frequency modulation adaptive coefficient.

[0018] As a further improvement of the present invention, the speed reference value Determined according to the highest or lowest speed of a single machine in the flywheel energy storage array;

[0019] First, the flywheel speed is divided into n min ,n l ,n h ,n max , lower than n l or higher than n h Need to Based on the relationship between speed and energy, the balanced power ΔP of the i-th flywheel unit is set. adj,i for:

[0020]

[0021] Where n i is the speed of the i-th unit; α is the balance coefficient; P fess,N is the single-unit rated power of the flywheel; when n h <n i ≤n max When the speed needs to be lowered, ΔP adj,i is positive, discharge; when n min <n i ≤n l When the speed needs to be increased, ΔP adj,i is negative, charging the energy storage;

[0022] Define the power change boundary value ΔP av , ΔP av Determined by the frequency modulation dead zone boundary value, the energy storage is ΔP av Charging and discharging does not cause the frequency to exceed the dead zone, and the power ΔP is balanced re Need to be adjusted to ΔP adj and ΔP av The smaller value of , that is:

[0023]

[0024] As a further improvement of the present invention, the frequency modulation adaptive coefficient m increases when the frequency is close to the limit value, and when the frequency exceeds the limit value, the frequency modulation is no longer responded.

[0025] As a further improvement of the present invention, in S4, according to the speed ni of the high-speed flywheel energy storage unit, the charging and discharging safety state Calculate the pre-allocated power of a single flywheel machine based on power constraints and other parameters; including:

[0026]

[0027] In the formula, is the charging power pre-allocated to the i-th flywheel, is the discharge power pre-allocated to the i-th flywheel, K is the number of flywheel units, is the power demand allocated to the flywheel array at time t, is the speed of the i-th flywheel unit at time t, n i,max is the maximum speed of the i-th flywheel unit, Represent the safe status of charging and discharging respectively.

[0028] As a further improvement of the present invention, in S5: estimating the speed of each high-speed flywheel unit at time t+T according to the pre-allocated power includes:

[0029]

[0030] In the formula, is the charging power allocated to the i-th flywheel at time t, which is a negative value; is the discharge power allocated to the i-th flywheel at time t, which is a positive value; E N,i is the rated energy of the i-th flywheel, p i T represents the energy stored in i flywheels after T cycles.

[0031] As a further improvement of the present invention, in S6, a security status check is performed, including:

[0032] 1) Charging safety status

[0033]

[0034] Where n i,N is the rated speed of the i-th flywheel unit; in the charging state, when the speed is less than or equal to 95% of the rated speed, it is considered to be in a completely safe state, and the corresponding safety value is 1; when the speed is in the range of 95%-100% of the rated speed, the safety state gradually decreases;

[0035] 2) Discharge safety status

[0036]

[0037] In the discharge state, when the speed is greater than or equal to 5% of the rated speed, it is a completely safe state, and the corresponding safety value is 1; when the speed is in the rated speed range of 5%-0%, the safety state gradually decreases.

[0038] As a further improvement of the present invention, it also includes adjusting the power of the flywheel energy storage unit whose safety state is less than 1:

[0039]

[0040] In the formula, p B is the power limit.

[0041] As a further improvement of the present invention, in S7: determining whether the charging and discharging power of each flywheel exceeds the power limit, and calculating the power shortage, specifically includes:

[0042]

[0043] In a second aspect, the present invention provides a primary frequency regulation system for a flywheel energy storage power station that takes into account both speed regulation and state safety, comprising:

[0044] Includes: dispatching layer, station control layer, and ground layer;

[0045] Wherein, the dispatching layer refers to power grid dispatching;

[0046] The station control layer includes energy storage primary frequency modulation control device, energy storage monitoring, wind and solar station monitoring module, network switch, and energy storage communication management machine;

[0047] The present formation is a flywheel array composed of multiple high-speed flywheel machines;

[0048] The energy storage primary frequency modulation device is connected to the grid connection point to detect the frequency change of the grid connection point, and calculate the power that each flywheel needs to bear according to the preset frequency dead zone and the speed and charge and discharge authority of each flywheel; the energy storage monitoring system is capable of monitoring the status information of each flywheel and managing the flywheel unit; the flywheel array receives the upper power grid dispatch, automatic primary frequency modulation or speed balancing instructions, and the primary frequency modulation instruction has a higher priority than the dispatch instruction;

[0049] The wind and solar station monitoring module is used to control the wind turbine power generation and photovoltaic power generation to respond to the frequency modulation power;

[0050] Each device communicates with each other through a local area network formed by a network switch;

[0051] The energy storage communication management machine is used for communication management of the flywheel array.

[0052] In a third aspect, the present invention provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the primary frequency regulation method of a flywheel energy storage power station that takes into account both speed regulation and state safety is implemented.

[0053] In a fourth aspect, the present invention provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the primary frequency regulation method of a flywheel energy storage power station that takes into account both speed regulation and state safety.

[0054] In a fifth aspect, the present invention provides a computer program product, the computer program product comprising computer instructions, the computer instructions instructing a computer to execute the primary frequency regulation method of a flywheel energy storage power station that takes into account both speed regulation and state safety.

[0055] The beneficial effects of the present invention compared with the prior art are as follows:

[0056] In view of the shortcomings of MW-class high-speed flywheels in practical applications, the present invention proposes a primary frequency regulation method for flywheel energy storage power stations that takes into account both speed adjustment and state safety. This method can effectively improve the frequency regulation capability and operating efficiency of flywheel energy storage arrays in new power systems by optimizing control strategies, especially while meeting high-frequency frequency regulation requirements, significantly improving the safety and stability of the system. Moreover, even when the initial speeds of individual flywheel units differ greatly, coordinated control can be used to achieve rapid convergence of the speeds of individual units, ensuring that the total speed of the flywheel array remains near the reference value for a long time. This optimization strategy not only improves the energy utilization efficiency of the entire system, but also reduces energy loss during the frequency regulation process. In addition, the present invention adopts a real-time safety status verification mechanism, combined with dynamic adjustment of the speed and charge and discharge status, to effectively ensure the safety of the flywheel unit and the system as a whole, and reduce the safety risks that may be caused by high-speed operation. This technology can also be applied to a variety of application scenarios, including wind storage, light storage and other joint operation modes, and has a wide range of applicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the embodiments of the present invention or the drawings of related technical solutions in the prior art are introduced below. It should be understood that the drawings introduced below are only for the convenience of clearly describing some embodiments of the technical solutions of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0058] Figure 1 It is a schematic diagram of a frequency modulation curve;

[0059] Figure 2 It is a frequency regulation control architecture for flywheel energy storage and wind and solar power stations;

[0060] Figure 3 A frequency regulation flow chart for flywheel energy storage in coordination with wind and solar power stations;

[0061] Figure 4 This is a schematic diagram of the calculation curve of the frequency modulation adaptive coefficient m. DETAILED DESCRIPTION

[0062] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and are not to be construed as limitations of the present invention. For the step numbers in the following embodiments, they are only provided for the convenience of explanation, and the order between the steps is not limited in any way, and the execution order of each step in the embodiment can be adaptively adjusted according to the understanding of those skilled in the art.

[0063] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0064] In order to achieve the control requirements of flywheel single machine speed consistency, flywheel energy state balanced regulation, and flywheel safe operation in the control process of flywheel energy storage power station, the present invention proposes a flywheel energy storage power station primary frequency adaptation method, system and device that take into account both speed adjustment and state safety.

[0065] Specifically, Figure 3 As shown, the first object of the present invention is to provide a primary frequency regulation method for a flywheel energy storage power station that takes into account both speed regulation and state safety, and the method comprises the following steps:

[0066] Step 1: Initialize the high-speed flywheel array parameters, including: flywheel single machine speed ni, charge and discharge safety status (1 means safe, 0 means unsafe), start / stop status, power constraint, etc.;

[0067] Step 2: The device detects the voltage, frequency, PCS initial power and other signals at the grid connection point, and calculates the power demand ΔP in two cases f :First, when the frequency is in the dead zone, the flywheel speed balancing operation is performed, and the speed balancing power ΔP re ; Second, when the frequency exceeds the dead zone, a frequency modulation operation is performed, ΔP f is the primary frequency modulation power.

[0068] Step 3: Convert the frequency modulation power demand ΔP f Distributed to flywheel energy storage, wind power, and photovoltaics. Since most wind power and photovoltaic units use the maximum power point tracking (MPPT) control method, wind and photovoltaic units cannot increase power when the frequency of the grid connection point decreases. In order to improve the consumption of wind and light, flywheel energy storage frequency regulation is preferred. When flywheel energy storage cannot meet the frequency regulation requirements, wind and solar power are selected to participate in the frequency regulation. Then, according to the real-time output of wind and light, the frequency regulation power of wind and light is proportionally allocated;

[0069] Step 4: Set the power of the high-speed flywheel unit in response to the primary frequency modulation of the power grid to ΔP FESS , according to the speed n of the high-speed flywheel energy storage unit i , safe state of charge and discharge Calculate the pre-allocated power of a single flywheel unit based on parameters such as power constraints;

[0070] Step 5: Estimate the speed of each flywheel at time t+T based on the pre-allocated power;

[0071] Step 6: Perform safety status verification and adjust the power of the flywheel energy storage unit whose safety status is less than 1;

[0072] Step 7: Perform power over-limit check and calculate power shortage;

[0073] Step 8: Determine whether the power shortage is less than the threshold value. If not, the power shortage will be redistributed to the high-speed flywheel whose speed does not exceed the limit. Return to step 5 and repeat the above calculation until there is no frequency regulation power shortage or each flywheel energy storage unit reaches the maximum power. If it is less than, the power allocated to each unit is output.

[0074] The present invention first initializes the flywheel parameters, including speed, charge and discharge safety status, start and stop status, and power constraints. Then, the grid connection point voltage, frequency, and PCS initial power are detected, and speed balancing or a frequency modulation operation is performed according to whether the frequency is in the dead zone. The frequency modulation power is preferentially allocated to the flywheel energy storage. When it is insufficient, wind and solar power are considered to participate and allocated in proportion. The single-machine pre-allocated power is calculated according to the flywheel speed, safety status, and power constraints, the speed at future times is estimated, and the safety status and power limit checks are performed. If there is a power shortage and the flywheel has not reached the maximum power, the power is reallocated and the calculation is repeated until there is no shortage or the flywheel is at full power. Finally, the allocated power of each unit is output. This process ensures the stability of the grid frequency, improves the absorption of wind and light, and ensures the safe operation of the flywheel energy storage unit.

[0075] Furthermore, by optimizing the power distribution and speed recovery management of the flywheel array, it is possible to quickly respond to the primary frequency regulation needs of the power grid while achieving efficient coordinated control of the flywheel array with new energy sources such as wind and solar power, thereby improving the energy utilization efficiency and operational safety of the system.

[0076] Therefore, in the frontier flywheel energy storage technology, the present invention takes high-speed MW-level flywheel single machine as the mainstream direction. Moreover, with the large-scale new energy grid connection, the power system's demand for high rotational inertia and high-frequency frequency modulation is increasing. A large-scale flywheel energy storage array composed of MW-level flywheel single machines can give full play to the flywheel's long life and fast response operating characteristics to support grid frequency modulation.

[0077] like Figure 2Another object of the present invention is to propose a system and device for primary frequency regulation of a flywheel energy storage power station that takes into account both speed regulation and state safety, which includes a dispatching layer, a station control layer, and a ground layer. The dispatching layer refers to power grid dispatching, the station control layer is composed of energy storage primary frequency regulation control devices, energy storage monitoring, wind and solar station monitoring modules, network switches, and energy storage communication management machines, and the ground layer is a flywheel array composed of multiple high-speed flywheel machines.

[0078] The energy storage primary frequency control device is responsible for detecting the frequency change of the grid connection point, and calculating the power that each flywheel needs to bear based on the preset frequency dead zone and the speed, charge and discharge authority of each flywheel. The energy storage monitoring system has the functions of monitoring the status information of each flywheel and managing the flywheel unit. The flywheel array can receive the upper grid dispatch, automatic primary frequency regulation or speed balancing instructions, and the primary frequency regulation instructions have a higher priority than the dispatch instructions.

[0079] In the above scheme, the dispatching layer is responsible for the overall dispatching and command issuance of the power grid to ensure the frequency stability and safe operation of the power grid. The station control layer includes energy storage primary frequency regulation control devices, energy storage monitoring, wind and solar station monitoring modules, network switches and energy storage communication management machines. This layer is a bridge connecting the dispatching layer and the ground layer, responsible for receiving dispatching instructions, monitoring flywheel status, calculating power distribution, etc. The ground layer is composed of a flywheel array composed of multiple high-speed flywheels, which is responsible for the actual execution of frequency regulation instructions and supports the frequency of the power grid by adjusting the speed.

[0080] Among them, the frequency modulation principle includes the following steps:

[0081] Frequency detection: The energy storage primary frequency control device detects the frequency changes of the grid connection point (i.e. the connection point between the flywheel energy storage power station and the power grid) in real time.

[0082] Power calculation: Calculate the power that each flywheel needs to bear based on the preset frequency dead zone (i.e. the allowable frequency fluctuation range) and the speed, charge and discharge authority and other information of each flywheel.

[0083] Instruction issuance: The calculated power instruction is sent to the flywheel array in the ground through the station control layer.

[0084] Execution adjustment: The flywheel array adjusts the speed according to the received instructions, thereby supporting and regulating the grid frequency.

[0085] Priority processing: The priority of the primary frequency modulation instruction is higher than the dispatch instruction. When the grid frequency fluctuates greatly, the system can quickly respond and execute the primary frequency modulation instruction to ensure the safe and stable operation of the grid.

[0086] As an example, the flywheel energy storage power station of the embodiment of the present invention has the characteristics of fast response speed, and can adjust the rotation speed in a very short time and support the frequency of the power grid. Through the calculation and allocation of the energy storage primary frequency regulation control device, the power distribution can be flexibly adjusted according to the actual situation of each flywheel to ensure the optimization of the frequency regulation effect. The system has complete monitoring and management functions, which can monitor the flywheel status information in real time and manage the flywheel unit. At the same time, the priority setting of the primary frequency regulation instruction ensures the safe and stable operation of the power grid in an emergency. The system can monitor and coordinate with other new energy sites (such as wind farms, photovoltaic power stations, etc.) to improve the flexibility and stability of the entire power grid.

[0087] The control method and system of the present invention are further described in detail below in combination with the accompanying drawings and specific embodiments.

[0088] Figure 1 is the active power-frequency characteristic curve of the energy storage equipped with the new energy station participating in the primary frequency regulation, where is the active power limiting coefficient β, that is, [f min ,f max ] is the dead zone of grid frequency regulation, [f n ,f m ] are the upper and lower limits of primary frequency modulation.

[0089] like Figure 2 As shown in the figure, the flywheel energy storage coordinated wind and solar power station frequency regulation control architecture consists of power grid dispatching, energy storage primary frequency regulation device, energy storage monitoring, wind turbine monitoring, energy storage communication management machine, and high-speed flywheel array. Among them, the energy storage primary frequency regulation device is connected to the grid connection point, responsible for detecting the frequency change of the grid connection point and issuing primary frequency regulation or speed balancing instructions; the energy storage monitoring system is responsible for monitoring the status information of the flywheel unit and managing the flywheel array; the wind and solar power station monitoring module is used to control the wind turbine power generation and photovoltaic power generation to respond to the frequency regulation power; the various devices communicate through a local area network formed by a network switch, supporting the IEC104 / 61850-MMS protocol.

[0090] Figure 3 This is a control method and implementation block diagram of flywheel energy storage cooperating with wind and solar power stations to perform primary frequency regulation, which specifically includes the following steps:

[0091] Step 1: Initialize the high-speed flywheel array parameters, including: flywheel single machine speed ni, charge and discharge safety status Start / stop status, power constraints, etc.

[0092] Step 2: The energy storage primary frequency control device detects the voltage, frequency, PCS initial power and other signals of the grid connection point, and calculates the power demand ΔP in two cases f:First, when the frequency is in the dead zone, the flywheel speed is balanced; second, when the frequency exceeds the dead zone, a frequency modulation operation is performed, ΔP f is the primary frequency modulation power.

[0093] Furthermore, in step 2: the power demand ΔP is calculated in two cases f for

[0094]

[0095] (1) When f min ≤f≤f max When the frequency modulation is not required, the speed n of the flywheel energy storage system can be adjusted to the reference value. Therefore, the speed reference value is defined as When the frequency modulation dead zone is reached and the flywheel speed is close to the maximum and minimum speed values, the balanced power ΔP is used. re Balance the speed of the flywheel energy storage system to the reference value The speed reference value Determined according to the highest or lowest speed of a single unit in the flywheel energy storage array. First, the flywheel speed is divided into n min ,n l ,n h ,n max , it is considered that lower than n l or higher than n h , need to Based on the relationship between speed and energy, the balanced power ΔP of the i-th flywheel unit is first set. adj,i for:

[0096]

[0097]

[0098] Where n i is the speed of the i-th unit; α is the balance coefficient; P fess,N is the single unit rated power of the flywheel. h <n i ≤n max When the speed needs to be lowered, ΔP adj,i is positive, discharge; when n min <n i ≤n l When the speed needs to be increased, ΔP adj,i Negative, that is, charging the energy storage.

[0099] In order to ensure that the charging and discharging behavior during the energy storage balancing process does not have a significant impact on the access point frequency, the power change boundary value ΔP is defined av, this value is determined by the frequency modulation dead zone boundary value. The energy storage is charged and discharged at this value without causing the frequency to exceed the dead zone, so the balanced power ΔP re Need to be adjusted to ΔP adj and ΔP av The smaller value of , that is:

[0100]

[0101] (2) When the frequency f exceeds the dead zone, a frequency modulation operation is required. The power demand of the frequency modulation is shown in formula (1), where δ% is the frequency modulation difference rate of the new energy station, P N is the rated power of the new energy station, f is the real-time frequency of the grid-connected point, and m is the frequency modulation adaptive coefficient. The value of m is as follows: Figure 4 As shown. Figure 4 As shown, the frequency modulation adaptive coefficient m increases when the frequency is close to the limit value, which plays a role in accelerating the frequency regulation; when the frequency exceeds the limit value, the system will no longer respond to the frequency modulation.

[0102] Step 3: Frequency modulation power allocation. Since wind power and photovoltaic units often operate in maximum power point tracking (MPPT) control mode and have no active reserve capacity, wind and photovoltaic units cannot generate additional power when the frequency at the grid connection point drops. Flywheel energy storage is used for frequency modulation first. When flywheel energy storage cannot meet the frequency modulation demand, wind power and photovoltaics participate in frequency modulation and only respond to downward frequency modulation. Based on the real-time output of wind and photovoltaic power, the abandoned wind and photovoltaic power are allocated according to the real-time power generation ratio;

[0103] Step 4: Set the power of the high-speed flywheel array in response to the primary frequency modulation of the power grid to P FESS The power control cycle is T. According to the speed ni of the high-speed flywheel energy storage unit, the charging and discharging safety state Calculate the pre-allocated power of a single flywheel unit based on parameters such as power constraints;

[0104] Further, in step 4: according to the speed ni of the high-speed flywheel energy storage unit, the charging and discharging safety state The pre-allocated power of a single flywheel unit is calculated based on power constraints and other parameters:

[0105]

[0106] In the formula, is the charging power pre-allocated to the i-th flywheel, is the discharge power pre-allocated to the i-th flywheel, K is the number of flywheel units, is the power demand allocated to the flywheel array at time t, is the speed of the i-th flywheel unit at time t, n i,max is the maximum speed of the i-th flywheel unit, Represent the safe status of charging and discharging respectively.

[0107] Step 5: Estimate the speed of each flywheel at time t+T based on the pre-allocated power;

[0108] Further, in step 5: the speed of each high-speed flywheel unit at time t+T is estimated based on the pre-allocated power,

[0109]

[0110] In the formula, is the charging power allocated to the i-th flywheel at time t, which is a negative value; is the discharge power allocated to the i-th flywheel at time t, which is a positive value; E N,i is the rated energy of the i-th flywheel. In this example, the control mode of the flywheel is to charge and discharge at constant power through PCS, so p i T represents the energy stored in i flywheels after T cycles.

[0111] Step 6: Perform safety status verification and adjust the power of the flywheel energy storage unit whose safety status is less than 1;

[0112] Further, in step 6: perform security status verification

[0113] (1) Charging safety status

[0114]

[0115] Where n i,N is the rated speed of the i-th flywheel unit. In the charging state, when the speed is less than or equal to 95% of the rated speed, it is considered to be a completely safe state, and the corresponding safety value is 1; when the speed is in the range of 95%-100% of the rated speed, the safety state gradually decreases.

[0116] (2) Discharge safety status

[0117]

[0118] In the discharge state, when the speed is greater than or equal to 5% of the rated speed, it is considered to be a completely safe state, and the corresponding safety value is 1; when the speed is in the rated speed range of 5%-0%, the safety state gradually decreases.

[0119] And adjust the power of the flywheel energy storage unit whose safety status is less than 1:

[0120]

[0121] Where p B is the power limit, which is set according to the charge and discharge status.

[0122] Step 7: Perform power over-limit check and calculate power shortage;

[0123] Further, in step 7: determine whether the charge and discharge power of each flywheel exceeds the power limit, and calculate the power shortage

[0124]

[0125] Step 8: Determine whether the power shortage is less than the threshold value. If not, the power shortage will be redistributed to the high-speed flywheel whose speed does not exceed the limit. Return to step 5 and repeat the above calculation until there is no frequency regulation power shortage or each flywheel energy storage unit reaches the maximum power. If it is less than, the power allocated to each unit is output.

[0126] Due to the adoption of the above technical solution, the present invention can achieve optimized management of the power and speed of the flywheel array while quickly responding to power demand. Even in the case where the initial speed of a single flywheel is highly discrete, the speed consistency of each flywheel can be adjusted in a short time, and the total speed of the flywheel array is near the reference value most of the time, which is convenient for charging or discharging the flywheel energy storage array, thereby improving the energy utilization efficiency of the entire system. In addition, due to the addition of inertial flywheels in the hybrid flywheel array, inertial support can be provided for the new power system, improving the stability of the system.

[0127] The third object of the embodiment of the present invention is to provide an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the primary frequency regulation method of the flywheel energy storage power station that takes into account both speed regulation and state safety when executing the computer program. It also includes a communication interface and a bus.

[0128] A fourth objective of an embodiment of the present invention is to provide a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the primary frequency regulation method of a flywheel energy storage power station that takes into account both speed regulation and state safety.

[0129] A fifth objective of an embodiment of the present invention is to provide a computer program product, the computer program product comprising computer instructions, the computer instructions instructing a computer to execute the above-mentioned primary frequency regulation method of a flywheel energy storage power station that takes into account both speed regulation and state safety.

[0130] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1A function specified in one or more boxes.

[0131] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process in the computer or other programmable device. Figure 1 A process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0132] The present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, readable storage media, optical storage, etc.) containing computer-usable program codes.

[0133] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0134] Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0135] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A primary frequency modulation method for a flywheel energy storage power station that takes into account both speed regulation and state safety, characterized in that: include: S1: Initialization of high-speed flywheel array parameters, including: single flywheel speed n i , safe state of charge and discharge Start-stop state, power constraint; S2: Obtain the voltage, frequency, and PCS initial power of the grid connection point, and calculate the power demand ΔP in two cases based on the voltage, frequency, and PCS initial power of the grid connection point. f :First, when the frequency is in the dead zone, the flywheel speed balancing operation is performed, and the speed balancing power ΔP re ; Second, when the frequency exceeds the dead zone, a frequency modulation operation is performed, ΔP f is the primary frequency modulation power; S3: The frequency modulation power demand ΔP f Allocate to flywheel energy storage, wind power, and photovoltaics; give priority to flywheel energy storage frequency regulation. If the frequency regulation power is insufficient, the wind and solar frequency regulation power will be allocated in proportion according to the real-time output of wind and solar power; S4: In frequency modulation power demand ΔP f After allocation, the power of the high-speed flywheel unit in response to the primary frequency modulation of the power grid is set to ΔP FESS ; According to the speed n of the high-speed flywheel energy storage unit i , safe state of charge and discharge Power constraint, calculate the pre-allocated power of a single flywheel unit; S5: estimating the speed of each flywheel at time t+T according to the pre-allocated power; S6: Perform safety status verification at the estimated speed of each flywheel at time t+T, and adjust the power of the flywheel energy storage unit whose safety status is less than 1; S7: After the power is adjusted, a power over-limit check is performed and the power shortage is calculated; S8: Determine whether the power shortage is less than the threshold value. If not, the power shortage is redistributed to the high-speed flywheel whose speed does not exceed the limit, and return to S5, and repeat until there is no frequency modulation power shortage or each flywheel energy storage unit reaches the maximum power; if it is less than, the power allocated to each unit is output.

2. A primary frequency modulation method for a flywheel energy storage power station taking into account both speed regulation and state safety according to claim 1, characterized in that: In S2: Calculate the power demand ΔP in two cases f , specifically: The first case: when f min ≤f≤f max When the frequency is not required, the speed n of the flywheel energy storage system is adjusted to the reference value. When the frequency modulation dead zone is reached and the flywheel speed is close to the maximum and minimum speed values, the balanced power ΔP is used. re Balance the speed of the flywheel energy storage system to the reference value The second case: When the frequency f exceeds the dead zone, a frequency modulation operation is required, using the power demand ΔP f Perform a frequency modulation operation, where δ% is the frequency modulation difference rate of the new energy station, P N is the rated power of the new energy station, f is the real-time frequency of the grid-connected point, and m is the frequency modulation adaptive coefficient.

3. A primary frequency modulation method for a flywheel energy storage power station taking into account both speed regulation and state safety according to claim 2, characterized in that: The speed reference value Determined according to the highest or lowest speed of a single machine in the flywheel energy storage array; First, the flywheel speed is divided into n min ,n l ,n h ,n max , lower than n l or higher than n h Need to Based on the relationship between speed and energy, the balanced power ΔP of the i-th flywheel unit is set. adj,i for: Where n i is the speed of the i-th unit; α is the balance coefficient; P fess,N is the single unit rated power of the flywheel; When n h <n i ≤n max When the speed needs to be lowered, ΔP adj,i is positive, discharge; when n min <n i ≤n l When the speed needs to be increased, ΔP adj,i is negative, charging the energy storage; Define the power change boundary value ΔP av , ΔP av Determined by the frequency modulation dead zone boundary value, the energy storage is ΔP av Charging and discharging does not cause the frequency to exceed the dead zone, and the power ΔP is balanced re Need to be adjusted to ΔP adj and ΔP av The smaller value of , that is:

4. A primary frequency modulation method for a flywheel energy storage power station taking into account both speed regulation and state safety according to claim 2, characterized in that: The frequency modulation adaptive coefficient m increases when the frequency is close to the limit value, and when the frequency exceeds the limit value, the frequency modulation is no longer responded.

5. A primary frequency modulation method for a flywheel energy storage power station taking into account both speed regulation and state safety according to claim 1, characterized in that: In S4, according to the speed n of the high-speed flywheel energy storage unit i , safe state of charge and discharge Calculate the pre-allocated power of a single flywheel unit based on parameters such as power constraints; include: In the formula, is the charging power pre-allocated to the i-th flywheel, is the discharge power pre-allocated to the i-th flywheel, K is the number of flywheel units, is the power demand allocated to the flywheel array at time t, is the speed of the i-th flywheel unit at time t, n i,max is the maximum speed of the i-th flywheel unit, Represent the safe status of charging and discharging respectively.

6. A primary frequency modulation method for a flywheel energy storage power station taking into account both speed regulation and state safety according to claim 1, characterized in that: In S5: the speed of each high-speed flywheel unit at time t+T is estimated based on the pre-allocated power, including: In the formula, is the charging power allocated to the i-th flywheel at time t, which is a negative value; is the discharge power allocated to the i-th flywheel at time t, which is a positive value; E N,i is the rated energy of the i-th flywheel, p i T represents the energy stored in i flywheels after T cycles.

7. A primary frequency modulation method for a flywheel energy storage power station taking into account both speed regulation and state safety according to claim 1, characterized in that: In S6, a safety status check is performed, including: 1) Charging safety status Where n i,N is the rated speed of the i-th flywheel unit; in the charging state, when the speed is less than or equal to 95% of the rated speed, it is considered to be in a completely safe state, and the corresponding safety value is 1; when the speed is in the range of 95%-100% of the rated speed, the safety state gradually decreases; 2) Discharge safety status In the discharge state, when the speed is greater than or equal to 5% of the rated speed, it is a completely safe state, and the corresponding safety value is 1; when the speed is in the rated speed range of 5%-0%, the safety state gradually decreases.

8. A primary frequency modulation method for a flywheel energy storage power station taking into account both speed regulation and state safety according to claim 7, characterized in that: It also includes power adjustment for flywheel energy storage units with a safety status less than 1: In the formula, p B is the power limit.

9. A primary frequency modulation method for a flywheel energy storage power station taking into account both speed regulation and state safety according to claim 8, characterized in that: In S7: determining whether the charging and discharging power of each flywheel exceeds the power limit, and calculating the power shortage, specifically including:

10. A primary frequency regulation system for a flywheel energy storage power station that takes into account both speed regulation and state safety, characterized in that: include: Dispatching layer, station control layer, and ground layer; Wherein, the dispatching layer refers to power grid dispatching; The station control layer includes energy storage primary frequency modulation control device, energy storage monitoring, wind and solar station monitoring module, network switch, and energy storage communication management machine; The present formation is a flywheel array composed of multiple high-speed flywheel machines; The energy storage primary frequency modulation device is connected to the grid connection point to detect the frequency change of the grid connection point, and calculate the power that each flywheel needs to bear according to the preset frequency dead zone and the speed and charge and discharge authority of each flywheel; the energy storage monitoring system is capable of monitoring the status information of each flywheel and managing the flywheel unit; the flywheel array receives the upper power grid dispatch, automatic primary frequency modulation or speed balancing instructions, and the primary frequency modulation instruction has a higher priority than the dispatch instruction; The wind and solar station monitoring module is used to control the wind turbine power generation and photovoltaic power generation to respond to the frequency modulation power; Each device communicates with each other through a local area network formed by a network switch; The energy storage communication management machine is used for communication management of the flywheel array.

11. An electronic device, characterized in that: It comprises a memory, a processor and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the primary frequency regulation method of a flywheel energy storage power station taking into account both speed regulation and state safety as described in any one of claims 1 to 9 is implemented.

12. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the primary frequency regulation method of a flywheel energy storage power station that takes into account both speed regulation and state safety as described in any one of claims 1 to 9 is implemented.

13. A computer program product, comprising computer instructions, characterized in that: The computer instructions instruct the computer to execute the primary frequency regulation method of a flywheel energy storage power station that takes into account both speed regulation and state safety as described in any one of claims 1-9.

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