Hybrid energy storage power distribution method based on power grid frequency modulation demand

Abstract

The invention discloses a hybrid energy storage power distribution method based on a power grid frequency modulation demand, and relates to the field of hybrid energy storage frequency modulation. The method comprises the steps that when a primary frequency modulation signal instruction and a secondary frequency modulation signal instruction are consistent in direction, a first total response instruction of the hybrid energy storage system and the working condition of the hybrid energy storage system are determined; based on the working condition of the hybrid energy storage system, aiming at prolonging the continuous regulation capability of the hybrid energy storage system, distributing a power instruction for each energy storage unit according to a first total response instruction of the hybrid energy storage system; when the directions of the primary frequency modulation signal instruction and the secondary frequency modulation signal instruction are opposite, taking the primary frequency modulation signal instruction as a second total response instruction, and distributing an initial power instruction for each energy storage unit; dynamically adjusting an initial power instruction of each energy storage unit by using a fuzzy controller; and determining a final power instruction of each energy storage unit according to the adjusted power instruction and rated power of each energy storage unit. The frequency modulation accuracy and stability can be improved, and the energy loss can be effectively reduced.

Description

Technical Field

[0001] The present application relates to the field of hybrid energy storage frequency regulation, and in particular to a hybrid energy storage power distribution method based on power grid frequency regulation requirements. Background Art

[0002] With the large-scale grid connection of new energy sources, the demand for grid frequency regulation is increasing and higher requirements are placed on the performance of frequency regulation power sources. Traditional thermal power units alone are difficult to meet the rapidly changing grid frequency regulation needs. Energy storage, as a new technology, has fast response and strong instantaneous power output capabilities, and has become an important resource to assist the frequency regulation of new power systems.

[0003] According to the time scale and capacity of energy storage, it can be divided into energy storage and power storage. However, a single energy storage method has gradually been unable to meet all needs, so the combination of multiple energy storage methods has begun to be widely used. Although the research on hybrid energy storage systems has made certain progress, current research is mostly focused on the power allocation strategy of hybrid energy storage systems participating in the primary frequency regulation or secondary frequency regulation of thermal power units. There is no research on the power allocation strategy when the energy storage system participates in both primary and secondary frequency regulation. Summary of the invention

[0004] The purpose of this application is to provide a hybrid energy storage power allocation method based on the frequency regulation requirements of the power grid, which can improve the accuracy and stability of frequency regulation and effectively reduce energy loss.

[0005] To achieve the above objectives, this application provides the following solutions:

[0006] The present application provides a hybrid energy storage power allocation method based on power grid frequency regulation demand, including: obtaining in real time a primary frequency modulation signal instruction, a secondary frequency modulation signal instruction, a thermal power unit load, a power grid frequency deviation, and a charge state of each energy storage unit in a hybrid energy storage system; when the primary frequency modulation signal instruction and the secondary frequency modulation signal instruction are in the same direction, determining a first total response instruction of the hybrid energy storage system according to the primary frequency modulation signal instruction, the secondary frequency modulation signal instruction, and the thermal power unit load; determining a hybrid energy storage system operating condition according to the charge state of each energy storage unit in the hybrid energy storage system; and based on the hybrid energy storage system operating condition, extending the hybrid energy storage system. The continuous regulation capability of the hybrid energy storage system is taken as the goal, and power instructions are allocated to each energy storage unit according to the first total response instruction of the hybrid energy storage system; when the primary frequency modulation signal instruction and the secondary frequency modulation signal instruction are in opposite directions, the primary frequency modulation signal instruction is used as the second total response instruction of the hybrid energy storage system, and initial power instructions are allocated to each energy storage unit according to the second total response instruction of the hybrid energy storage system; according to the frequency deviation of the power grid, the initial power instruction of each energy storage unit is dynamically adjusted by using a fuzzy controller; according to the adjusted power instructions of each energy storage unit and the rated power of each energy storage unit, the final power instruction of each energy storage unit is determined.

[0007] According to the specific embodiments provided in this application, this application has the following technical effects:

[0008] The present application provides a hybrid energy storage power allocation method based on the frequency regulation demand of the power grid. For the two working conditions where the primary frequency regulation signal instruction and the secondary frequency regulation signal instruction are in the same direction or in opposite directions, different power allocation strategies are formulated by comprehensively considering the charge state of each energy storage unit in the hybrid energy storage system, and a fuzzy controller is used to dynamically adjust the initial power instruction of each energy storage unit, so as to flexibly adjust the power allocation, significantly improve the adaptability and flexibility of the strategy, greatly enhance the accuracy and stability of frequency regulation, and effectively reduce energy loss. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0010] Figure 1 A schematic diagram of a flow chart of a hybrid energy storage power allocation method based on power grid frequency regulation requirements provided in one embodiment of the present application;

[0011] Figure 2 A schematic diagram of the overall control process of a hybrid energy storage system when the primary and secondary frequency modulation signal instructions are in opposite directions is provided in another embodiment of the present application. DETAILED DESCRIPTION

[0012] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0013] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0014] Power-based energy storage performs well in applications that require rapid response to frequent power demands due to its fast charging and discharging capabilities. It mainly undertakes frequency regulation tasks in the operation of power systems. Representative technologies include flywheel energy storage, supercapacitors, and superconducting magnetic energy storage. In contrast, energy-based energy storage is known for its high energy storage density and large storage capacity. It is mainly suitable for occasions that require continuous and large energy input. In situations such as power grid peak regulation where long-term and large-capacity energy input is required, energy-based energy storage plays a vital role. The main representative technologies are pumped storage, electrochemical energy storage, and compressed air energy storage.

[0015] When applying hybrid energy storage systems to different scenarios, a key step is to optimize the power allocation strategy between different energy storage units. The core strategy is to perform frequency decomposition and reorganization of the real-time output power of the hybrid energy storage system to ensure that each energy storage medium can bear the corresponding frequency component according to its inherent characteristics to meet the actual power demand and improve the overall operating efficiency of the system.

[0016] In view of this, in order to determine the power allocation strategy when the energy storage system participates in both primary and secondary frequency regulation, in an exemplary embodiment, Figure 1 As shown, a hybrid energy storage power distribution method based on power grid frequency regulation requirements is provided, including the following steps 101 to 107. Among them:

[0017] Step 101: Acquire in real time the primary frequency modulation signal instruction, the secondary frequency modulation signal instruction, the load of the thermal power unit, the grid frequency deviation, and the charge state of each energy storage unit in the hybrid energy storage system.

[0018] Step 102: When the primary frequency modulation signal instruction and the secondary frequency modulation signal instruction are in the same direction, a first total response instruction of the hybrid energy storage system is determined according to the primary frequency modulation signal instruction, the secondary frequency modulation signal instruction and the load of the thermal power unit.

[0019] Step 103: Determine the operating condition of the hybrid energy storage system according to the charge state of each energy storage unit in the hybrid energy storage system.

[0020] Step 104: Based on the operating condition of the hybrid energy storage system and with the goal of extending the continuous regulation capability of the hybrid energy storage system, power instructions are allocated to each energy storage unit according to the first total response instruction of the hybrid energy storage system.

[0021] Step 105: When the primary frequency modulation signal instruction and the secondary frequency modulation signal instruction are in opposite directions, the primary frequency modulation signal instruction is used as the second total response instruction of the hybrid energy storage system, and an initial power instruction is allocated to each energy storage unit according to the second total response instruction of the hybrid energy storage system.

[0022] Step 106: According to the grid frequency deviation, the fuzzy controller is used to dynamically adjust the initial power command of each energy storage unit.

[0023] Step 107: Determine the final power command of each energy storage unit according to the adjusted power command of each energy storage unit and the rated power of each energy storage unit.

[0024] By implementing the above steps 101 to 107, for the two working conditions where the primary frequency modulation signal instruction and the secondary frequency modulation signal instruction are in the same direction or in opposite directions, different power allocation strategies are formulated by comprehensively considering the charge state of each energy storage unit in the hybrid energy storage system, and the fuzzy controller is used to dynamically adjust the initial power instruction of each energy storage unit, so as to flexibly adjust the power allocation, significantly improve the adaptability and flexibility of the strategy, greatly enhance the accuracy and stability of frequency modulation, and effectively reduce energy loss.

[0025] In another exemplary embodiment of the present application, the charge state of each energy storage unit in the hybrid energy storage system obtained in the above step 101 has a value range of 0 to 1, indicating the amount of electricity currently stored in the energy storage unit. The secondary frequency modulation signal instruction is specifically a grid secondary frequency modulation signal AGC (Automatic Generation Control) instruction. In addition to obtaining the primary frequency modulation signal instruction P1 and the secondary frequency modulation signal instruction P AGG 、The load of thermal power unit P g , grid frequency deviation Δf and the charge state of each energy storage unit in the hybrid energy storage system, and the rated power of each energy storage unit can also be obtained.

[0026] This application formulates different power allocation strategies according to whether the directions of the primary frequency modulation signal instruction and the secondary frequency modulation signal instruction are consistent. The following introduces two power allocation strategies respectively.

[0027] (i) Power allocation strategy when the primary frequency modulation signal instruction and the secondary frequency modulation signal instruction directions are consistent.

[0028] In another exemplary embodiment of the present application, when the primary frequency modulation signal P1 and the secondary frequency modulation signal P AGC When the action direction is the same, the hybrid energy storage system distributes power to the primary and secondary frequency modulation at the same time. Since the secondary frequency modulation command signal is generally a step change, the thermal power unit will increase or decrease the load according to the AGC command signal. Therefore, the flywheel and flow battery respond to the secondary frequency modulation signal and the output P of the thermal power unit at the same time. g The difference and the primary signal instruction P1, the calculation formula of the first total response instruction of the hybrid energy storage system in the above step 102 is:

[0029] P2=P AGC -P g +P1;

[0030] Where, P2 is the first total response instruction, P AGG is the secondary frequency modulation signal instruction, Pg is the load of the thermal power unit, and P1 is the primary frequency modulation signal instruction.

[0031] In another exemplary embodiment of the present application, in order to avoid the problem of overcharging and overdischarging and extend the life of energy storage, when the hybrid energy storage responds to the signal instruction P2 at the same time, it is necessary to consider the SOC status of both, divide the range of the SOC interval of the flywheel and the battery, and determine the operating conditions of the hybrid energy storage system under different SOC combination states. Then the above step 103 can be replaced by steps 201 to 203:

[0032] Step 201: The state of charge of each energy storage unit in the hybrid energy storage system is divided into intervals, and the state of charge intervals of each energy storage unit are arbitrarily combined to obtain a plurality of state of charge combinations.

[0033] Step 202: Determine the corresponding relationship between the state of charge combination and the operating condition of the hybrid energy storage system.

[0034] Step 203: According to the charge state of each energy storage unit in the hybrid energy storage system, the operating state of the hybrid energy storage system is determined by using the corresponding relationship between the charge state combination and the operating state of the hybrid energy storage system.

[0035] In another exemplary embodiment of the present application, when the hybrid energy storage system includes flywheel energy storage and all-vanadium liquid flow battery, the corresponding relationship between the state of charge combination and the operating condition of the hybrid energy storage system is:

[0036] When the charge state range of the flywheel energy storage is [0.1, 0.3), and the charge state range of the all-vanadium liquid flow battery is [0.1, 0.3), the operating condition of the hybrid energy storage system is S1.

[0037] When the charge state range of the flywheel energy storage is [0.3, 0.7) and the charge state range of the all-vanadium liquid flow battery is [0.1, 0.3), the operating condition of the hybrid energy storage system is S2.

[0038] When the charge state range of the flywheel energy storage is [0.7, 0.9] and the charge state range of the all-vanadium liquid flow battery is [0.1, 0.3), the operating condition of the hybrid energy storage system is S3.

[0039] When the charge state range of the flywheel energy storage is [0.1, 0.3) and the charge state range of the all-vanadium liquid flow battery is [0.3, 0.7), the operating condition of the hybrid energy storage system is S4.

[0040] When the charge state range of the flywheel energy storage is [0.3, 0.7), and the charge state range of the all-vanadium liquid flow battery is [0.3, 0.7), the operating condition of the hybrid energy storage system is S5.

[0041] When the charge state range of the flywheel energy storage is [0.7, 0.9], and the charge state range of the all-vanadium liquid flow battery is [0.3, 0.7), the operating condition of the hybrid energy storage system is S6.

[0042] When the state of charge range of the flywheel energy storage is [0.1, 0.3) and the state of charge range of the all-vanadium liquid flow battery is [0.7, 0.9], the operating condition of the hybrid energy storage system is S7.

[0043] When the charge state range of the flywheel is [0.3, 0.7) and the charge state range of the all-vanadium liquid flow battery is [0.7, 0.9], the operating condition of the hybrid energy storage system is S8.

[0044] When the state of charge range of the flywheel energy storage is [0.7, 0.9] and the state of charge range of the all-vanadium liquid flow battery is [0.7, 0.9], the operating condition of the hybrid energy storage system is S9.

[0045] The corresponding relationship between the state of charge combination and the operating conditions of the hybrid energy storage system can be seen in Table 1.

[0046] Table 1 Classification of hybrid energy storage system operating conditions

[0047]

[0048]

[0049] In another exemplary embodiment of the present application, the power command requirements are comprehensively considered, and the flywheel energy storage is given priority to respond when the flywheel energy storage SOC is suitable for responding to the command, and the battery energy storage is given priority to respond when the flywheel energy storage SOC is too high or too low, and is not suitable for responding to the command. When the SOC of the hybrid energy storage system is too high or too low, the dynamic remaining capacity ratio allocation strategy responds, so as to achieve the purpose of extending the continuous adjustment capability of the hybrid energy storage system. Then the above step 104 can be replaced by the following steps 301 to 303:

[0050] Step 301: When the first total response instruction is less than 0 and the hybrid energy storage system operating condition is S4, S7 or S8, according to the formula Assign power instructions to each energy storage unit; where P f is the flywheel energy storage power command, P v is the power command of the all-vanadium liquid flow battery, P2 is the first total response command, P fm is the flywheel energy storage rated power, P vm Rated power of all-vanadium redox flow battery.

[0051] If the first total response command is less than 0, the hybrid energy storage system is charged. When the hybrid energy storage system is in S4, S7 or S8 operating conditions, the flywheel SOC is lower than the battery SOC, so the flywheel is charged first and the battery is charged as a supplement.

[0052] Step 302: When the first total response instruction is less than 0 and the hybrid energy storage system operating condition is S2, S3 or S6, according to the formula Allocate power instructions to each energy storage unit.

[0053] When the hybrid energy storage system is in S2, S3 or S6 operating conditions, the battery SOC is lower than that of the flywheel, so the battery is charged first and the flywheel supplements the output.

[0054] Step 303: When the first total response instruction is less than 0 and the hybrid energy storage system operating condition is S1, S5 or S9, according to the formula Assign power instructions to each energy storage unit; where SOC f is the state of charge of the flywheel energy storage, SOC v is the state of charge of the all-vanadium liquid flow battery.

[0055] When the hybrid energy storage system is in S1, S5 or S9 conditions, the SOC of the flywheel and the battery are almost the same.

[0056] This strategy adopts a strategy of dynamically adjusting the output of both the flywheel and the battery according to the SOC state to extend the overall output capacity of the hybrid energy storage system.

[0057] In another exemplary embodiment of the present application, the above step 104 may also be replaced by the following steps 401 to 403:

[0058] Step 401: When the first total response instruction is greater than 0 and the hybrid energy storage system operating condition is S2, S3 or S6, according to the formula Assign power instructions to each energy storage unit; where P f is the flywheel energy storage power command, P v is the power command of the all-vanadium liquid flow battery, P2 is the first total response command, P fm is the flywheel energy storage rated power, P vm Rated power of all-vanadium redox flow battery.

[0059] If the first total response command is greater than 0, the hybrid energy storage system discharges. When the hybrid energy storage system is in S2, S3 or S6 operating conditions, the flywheel SOC is higher than the battery SOC, so the flywheel is discharged first and the battery is used as a supplement.

[0060] Step 402: When the first total response instruction is greater than 0 and the hybrid energy storage system operating condition is S4, S7 or S8, according to the formula Allocate power instructions to each energy storage unit.

[0061] When the hybrid energy storage system is in S4, S7 or S8 operating conditions, the battery has a higher SOC than the flywheel, so the battery discharges first and the flywheel supplements the output.

[0062] Step 403: When the first total response instruction is greater than 0 and the hybrid energy storage system operating condition is S1, S5 or S9, according to the formula Assign power instructions to each energy storage unit; where SOC f is the state of charge of the flywheel energy storage, SOC v is the state of charge of the all-vanadium liquid flow battery.

[0063] When the hybrid energy storage system is in S1, S5 or S9 operating conditions, the SOC of the flywheel and the battery are not much different. Therefore, a strategy of dynamically adjusting the output of both the flywheel and the battery according to the SOC status is adopted to extend the overall output capacity of the hybrid energy storage system.

[0064] (ii) Power allocation strategy when the primary frequency modulation signal instruction and the secondary frequency modulation signal instruction are in opposite directions.

[0065] In another exemplary embodiment of the present application, when the primary frequency regulation instruction conflicts with the secondary frequency regulation instruction, that is, the two have opposite directions of action, the power grid assessment rules stipulate that when the primary frequency regulation action direction of the unit is opposite to the AGC instruction direction, the unit should set the primary frequency regulation priority, and because the primary frequency regulation can quickly stabilize the frequency of the power system, it can effectively prevent the risk of system instability or even collapse caused by a large deviation of the frequency from the normal value, and the execution of the primary frequency regulation instruction should also be given priority. Therefore, the total response instruction of the flywheel and flow battery is:

[0066] P2=P1

[0067] In order to more accurately deal with the conflict of frequency modulation instructions and fully consider the current operation status and actual needs of the power grid, when the hybrid energy storage system includes flywheel energy storage and all-vanadium liquid flow batteries, the operating conditions are first divided according to the SOC of the flywheel and the battery, and the initial output instructions P of the flywheel and the battery are determined. f1 and P v1 This process is the same as the power allocation strategy when the directions of the primary frequency modulation signal instruction and the secondary frequency modulation signal instruction are consistent. Then the above step 105 allocates the initial power instruction to each energy storage unit according to the second total response instruction of the hybrid energy storage system, which can be replaced by the following steps 501 to 502:

[0068] Step 501: Determine the operating condition of the hybrid energy storage system according to the charge state of each energy storage unit in the hybrid energy storage system.

[0069] Step 502: Based on the operating condition of the hybrid energy storage system and with the goal of extending the continuous regulation capability of the hybrid energy storage system, power instructions are allocated to each energy storage unit according to the second total response instruction of the hybrid energy storage system.

[0070] In another exemplary embodiment of the present application, compared with the flywheel energy storage system, the instantaneous charge and discharge power capacity of the flow battery is insufficient. Frequent charge and discharge will cause the life of the flow battery to decrease rapidly. Consider introducing a fuzzy controller to further dynamically adjust the output of the hybrid energy storage. The flywheel energy storage system responds more to short-term and low-power regulation instructions, thereby improving the overall life of the hybrid energy storage system. The core of the dynamic adjustment is to adjust the initial output instruction P of the flow battery. v1 Multiply by the battery output adjustment factor T which is flexibly adjusted according to the changes in system frequency.

[0071] Since the flywheel has fast charging and discharging capabilities and can quickly respond to frequent power demands, when |Δf| is small and If the frequency is large, T should be reduced, the output of battery energy storage should be reduced, and the flywheel energy storage should take on more frequency regulation tasks and respond quickly to balance the frequency fluctuation of the power grid; When |Δf| is small, the load fluctuation is smooth, the frequency regulation demand is reduced, T is appropriately increased, the output of the battery energy storage is increased, and the output distribution between the flywheel and the battery energy storage is coordinated; when |Δf| is large, T should be increased to give full play to the advantages of the large energy capacity of the battery energy storage. Therefore, the overall control strategy of the hybrid energy storage system is as follows Figure 2 shown.

[0072] For the battery output adjustment coefficient T that needs to be adjusted, a two-input, single-output fuzzy controller is designed. Frequency change rate The fuzzy domain of is [-0.01, 0.01], and the fuzzy subsets are {NB (negative large), NS (negative small), NZ (negative zero), PZ (positive zero), PS (positive small), PB (positive large)}; the fuzzy domain of Δf is [-0.1, 0.1], and the fuzzy subsets are {NB (negative large), NS (negative small), NZ (negative zero), PZ (positive zero), PS (positive small), PB (positive large)}; the fuzzy domain of battery output adjustment coefficient T is [0, 1], and the fuzzy subsets are {NB (negative large), NM (negative medium), NS (negative small), NZ (negative zero), PZ (positive zero), PS (positive small), PM (positive medium), PB (positive large)}; the fuzzy rules are shown in Table 2.

[0073] Table 2 Fuzzy rules

[0074]

[0075] When the hybrid energy storage system includes flywheel energy storage and all-vanadium liquid flow batteries, the above step 106 can be replaced by the following steps 601 to 602:

[0076] Step 601: Input the real-time acquired grid frequency deviation and frequency change rate into the fuzzy controller to obtain the real-time battery output adjustment coefficient.

[0077] Step 602: According to the real-time battery output adjustment coefficient, according to the formula Dynamically adjust the initial power command of each energy storage unit; where P f1 is the initial power command of flywheel energy storage, P v1 is the initial power command of the all-vanadium liquid flow battery, T is the battery output adjustment coefficient, P f,T is the power command after flywheel energy storage adjustment, P v,T Adjusted power command for all-vanadium redox flow battery.

[0078] In another exemplary embodiment of the present application, after dynamically adjusting the output distribution of the flywheel and the battery based on fuzzy control, the power command of the hybrid energy storage system is limited by its rated power. When the hybrid energy storage system includes flywheel energy storage and all-vanadium liquid flow batteries, if the second total response command is less than 0, the calculation formula for the final power command of each energy storage unit in the above step 107 is:

[0079]

[0080] Where P f ′ is the final power command of the flywheel energy storage, P v ′ is the final power instruction of the all-vanadium liquid flow battery, P f,T is the power command after flywheel energy storage adjustment, P v,T is the adjusted power command of the all-vanadium liquid flow battery, P fm is the flywheel energy storage rated power, P vm Rated power of all-vanadium redox flow battery.

[0081] In another exemplary embodiment of the present application, when the hybrid energy storage system includes flywheel energy storage and all-vanadium liquid flow battery, if the second total response instruction is greater than 0, the calculation formula of the final power instruction of each energy storage unit in the above step 107 can also be:

[0082]

[0083] Where P f ′ is the final power command of the flywheel energy storage, P v ′ is the final power instruction of the all-vanadium liquid flow battery, P f,T is the power command after flywheel energy storage adjustment, P v,T is the adjusted power command of the all-vanadium liquid flow battery, P fm is the flywheel energy storage rated power, P vm Rated power of all-vanadium redox flow battery.

[0084] This application proposes a power allocation strategy that considers the participation of hybrid energy storage in primary and secondary frequency regulation, and performs parameter self-adjustment based on system characteristics, so that the power allocation strategy can be flexibly adjusted according to the actual needs and operating status of the power grid, especially in power grids with a high proportion of renewable energy generation to handle higher frequency and greater power frequency regulation needs, so as to improve overall efficiency and reduce energy loss.

[0085] This application cleverly combines the respective advantages of energy-type energy storage and power-type energy storage, and innovatively proposes a hybrid energy storage parameter self-adjustment control strategy for the frequency regulation needs of the power grid. Not only does it comprehensively consider the power distribution problem of primary frequency regulation and secondary frequency regulation, but it also achieves close coordination between the two. By comprehensively considering the SOC of the energy storage system, according to the actual needs and operating status of the power grid, using output distribution strategies and dynamic parameter adjustment methods for different working conditions, the power distribution is flexibly adjusted, which significantly improves the adaptability and flexibility of the strategy, greatly enhances the accuracy and stability of frequency regulation, effectively reduces energy loss, and provides strong support for the stability of power grid frequency.

[0086] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0087] This article uses specific examples to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and core ideas of this application. At the same time, for those skilled in the art, according to the ideas of this application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims

1. A hybrid energy storage power allocation method based on power grid frequency regulation requirements, characterized in that: include: Real-time acquisition of primary frequency modulation signal instructions, secondary frequency modulation signal instructions, thermal power unit load, grid frequency deviation, and the charge status of each energy storage unit in the hybrid energy storage system; When the directions of the primary frequency modulation signal instruction and the secondary frequency modulation signal instruction are consistent, the first total response instruction of the hybrid energy storage system is determined according to the primary frequency modulation signal instruction, the secondary frequency modulation signal instruction and the load of the thermal power unit; Determine the operating condition of the hybrid energy storage system according to the charge state of each energy storage unit in the hybrid energy storage system; Based on the operating conditions of the hybrid energy storage system, with the goal of extending the continuous regulation capability of the hybrid energy storage system, power instructions are allocated to each energy storage unit according to the first total response instruction of the hybrid energy storage system; When the primary frequency modulation signal instruction and the secondary frequency modulation signal instruction are in opposite directions, the primary frequency modulation signal instruction is used as the second total response instruction of the hybrid energy storage system, and an initial power instruction is allocated to each energy storage unit according to the second total response instruction of the hybrid energy storage system; According to the grid frequency deviation, the fuzzy controller is used to dynamically adjust the initial power command of each energy storage unit; The final power command of each energy storage unit is determined according to the adjusted power command of each energy storage unit and the rated power of each energy storage unit.

2. The hybrid energy storage power distribution method based on power grid frequency modulation demand according to claim 1 is characterized in that: The calculation formula of the first total response command of the hybrid energy storage system is: P2=P AGC -P g +P1; Where, P2 is the first total response instruction, P AGG is the secondary frequency modulation signal instruction, P g is the load of the thermal power unit, and P1 is the primary frequency modulation signal instruction.

3. The hybrid energy storage power distribution method based on power grid frequency modulation demand according to claim 1 is characterized in that: According to the charge state of each energy storage unit in the hybrid energy storage system, the operating conditions of the hybrid energy storage system are determined, including: The state of charge of each energy storage unit in the hybrid energy storage system is divided into intervals, and the state of charge intervals of each energy storage unit are arbitrarily combined to obtain multiple state of charge combinations; Determine the corresponding relationship between the state of charge combination and the operating conditions of the hybrid energy storage system; According to the charge state of each energy storage unit in the hybrid energy storage system, the operating condition of the hybrid energy storage system is determined by utilizing the corresponding relationship between the charge state combination and the operating condition of the hybrid energy storage system.

4. The hybrid energy storage power distribution method based on power grid frequency modulation demand according to claim 3 is characterized in that: When the hybrid energy storage system includes flywheel energy storage and all-vanadium liquid flow battery, the corresponding relationship between the state of charge combination and the operating condition of the hybrid energy storage system is: When the charge state interval of the flywheel energy storage is [0.1, 0.3), and the charge state interval of the all-vanadium liquid flow battery is [0.1, 0.3), the operating condition of the hybrid energy storage system is S1; When the charge state interval of the flywheel energy storage is [0.3, 0.7), and the charge state interval of the all-vanadium liquid flow battery is [0.1, 0.3), the hybrid energy storage system operating condition is S2; When the charge state interval of the flywheel energy storage is [0.7, 0.9], and the charge state interval of the all-vanadium liquid flow battery is [0.1, 0.3), the hybrid energy storage system operating condition is S3; When the charge state interval of the flywheel energy storage is [0.1, 0.3), and the charge state interval of the all-vanadium liquid flow battery is [0.3, 0.7), the hybrid energy storage system operating condition is S4; When the charge state interval of the flywheel energy storage is [0.3, 0.7), and the charge state interval of the all-vanadium liquid flow battery is [0.3, 0.7), the hybrid energy storage system operating condition is S5; When the charge state interval of the flywheel energy storage is [0.7, 0.9], and the charge state interval of the all-vanadium liquid flow battery is [0.3, 0.7), the hybrid energy storage system operating condition is S6; When the charge state interval of the flywheel energy storage is [0.1, 0.3), and the charge state interval of the all-vanadium liquid flow battery is [0.7, 0.9], the hybrid energy storage system operating condition is S7; When the charge state range of the flywheel is [0.3, 0.7), and the charge state range of the all-vanadium liquid flow battery is [0.7, 0.9], the hybrid energy storage system operating condition is S8; When the state of charge range of the flywheel energy storage is [0.7, 0.9] and the state of charge range of the all-vanadium liquid flow battery is [0.7, 0.9], the operating condition of the hybrid energy storage system is S9.

5. The hybrid energy storage power distribution method based on power grid frequency modulation demand according to claim 4 is characterized in that: Based on the operating conditions of the hybrid energy storage system, with the goal of extending the continuous regulation capability of the hybrid energy storage system, power instructions are allocated to each energy storage unit according to the first total response instruction of the hybrid energy storage system, specifically including: When the first total response command is less than 0 and the hybrid energy storage system operating condition is S4, S7 or S8, according to the formula Assign power instructions to each energy storage unit; where P f is the flywheel energy storage power command, P v is the power command of the all-vanadium liquid flow battery, P2 is the first total response command, P fm is the flywheel energy storage rated power, P vm is the rated power of the all-vanadium liquid flow battery; When the first total response command is less than 0 and the hybrid energy storage system operating condition is S2, S3 or S6, according to the formula Allocating power instructions to each energy storage unit; When the first total response command is less than 0 and the hybrid energy storage system operating condition is S1, S5 or S9, according to the formula Assign power instructions to each energy storage unit; where SOC f is the state of charge of the flywheel energy storage, SOC v is the state of charge of the all-vanadium liquid flow battery.

6. The hybrid energy storage power distribution method based on power grid frequency modulation demand according to claim 4 or 5, characterized in that: Based on the operating conditions of the hybrid energy storage system, with the goal of extending the continuous regulation capability of the hybrid energy storage system, power instructions are allocated to each energy storage unit according to the first total response instruction of the hybrid energy storage system, specifically including: When the first total response command is greater than 0 and the hybrid energy storage system operating condition is S2, S3 or S6, according to the formula Assign power instructions to each energy storage unit; where P f is the flywheel energy storage power command, P v is the power command of the all-vanadium liquid flow battery, P2 is the first total response command, P fm is the flywheel energy storage rated power, P vm is the rated power of the all-vanadium liquid flow battery; When the first total response command is greater than 0 and the hybrid energy storage system operating condition is S4, S7 or S8, according to the formula Allocating power instructions to each energy storage unit; When the first total response command is greater than 0 and the hybrid energy storage system operating condition is S1, S5 or S9, according to the formula Assign power instructions to each energy storage unit; where SOC f is the state of charge of the flywheel energy storage, SOC v is the state of charge of the all-vanadium liquid flow battery.

7. The hybrid energy storage power distribution method based on power grid frequency modulation demand according to claim 1 is characterized in that: According to the second total response instruction of the hybrid energy storage system, an initial power instruction is allocated to each energy storage unit, specifically including: Determine the operating condition of the hybrid energy storage system according to the charge state of each energy storage unit in the hybrid energy storage system; Based on the operating conditions of the hybrid energy storage system, with the goal of extending the continuous regulation capability of the hybrid energy storage system, power instructions are allocated to each energy storage unit according to the second total response instruction of the hybrid energy storage system.

8. The hybrid energy storage power distribution method based on power grid frequency modulation demand according to claim 1 is characterized in that: When the hybrid energy storage system includes flywheel energy storage and all-vanadium liquid flow batteries, the fuzzy controller is used to dynamically adjust the initial power instructions of each energy storage unit according to the grid frequency deviation, including: The real-time grid frequency deviation and frequency change rate are input into the fuzzy controller to obtain the real-time battery output adjustment coefficient; According to the real-time battery output adjustment coefficient, according to the formula Dynamically adjust the initial power command of each energy storage unit; where P f1 is the initial power command of flywheel energy storage, P v1 is the initial power command of the all-vanadium liquid flow battery, T is the battery output adjustment coefficient, P fT is the power command after flywheel energy storage adjustment, P v,T Adjusted power command for all-vanadium redox flow battery.

9. The hybrid energy storage power distribution method based on power grid frequency modulation demand according to claim 1 is characterized in that: When the hybrid energy storage system includes flywheel energy storage and all-vanadium liquid flow batteries, if the second total response command is less than 0, the calculation formula for the final power command of each energy storage unit is: Where P f ′ is the final power command of the flywheel energy storage, P v ′ is the final power instruction of the all-vanadium liquid flow battery, P f,T is the power command after flywheel energy storage adjustment, P v,T is the adjusted power command of the all-vanadium liquid flow battery, P fm is the flywheel energy storage rated power, P vm Rated power of all-vanadium redox flow battery.

10. The hybrid energy storage power distribution method based on power grid frequency regulation demand according to claim 1 or 9, characterized in that: When the hybrid energy storage system includes flywheel energy storage and all-vanadium liquid flow batteries, if the second total response command is greater than 0, the calculation formula for the final power command of each energy storage unit is: Where P f ′ is the final power command of the flywheel energy storage, P v ′ is the final power instruction of the all-vanadium liquid flow battery, P f,T is the power command after flywheel energy storage adjustment, P v,T is the adjusted power command of the all-vanadium liquid flow battery, P fm is the flywheel energy storage rated power, P vm Rated power of all-vanadium redox flow battery.

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