A hybrid energy storage power distribution method based on grid frequency regulation requirements

Abstract

The application discloses a hybrid energy storage power distribution method based on power grid frequency modulation demand, and relates to the field of hybrid energy storage frequency modulation. The method comprises the following steps: when the primary frequency modulation signal instruction and the secondary frequency modulation signal instruction are consistent, determining the first total response instruction of the hybrid energy storage system and the working condition of the hybrid energy storage system; based on the working condition of the hybrid energy storage system, distributing power instructions to each energy storage unit according to the first total response instruction of the hybrid energy storage system, with the target of prolonging the continuous adjustment capacity of the hybrid energy storage system; when the primary frequency modulation signal instruction and the secondary frequency modulation signal instruction are opposite, taking the primary frequency modulation signal instruction as the second total response instruction, and distributing initial power instructions to each energy storage unit; dynamically adjusting the initial power instructions of each energy storage unit by using a fuzzy controller; and determining the final power instructions of each energy storage unit according to the adjusted power instructions and the rated power of each energy storage unit. The application can improve the accuracy and stability of frequency modulation, and effectively reduce energy loss.

Description

TECHNICAL FIELD

[0001] The application relates to the field of hybrid energy storage frequency modulation, and particularly relates to a hybrid energy storage power distribution method based on power grid frequency modulation demand. BACKGROUND

[0002] With large-scale grid connection of new energy, the demand for power grid frequency modulation is increasing, and higher performance of frequency modulation power supply is required. Only traditional thermal power units cannot meet the demand for rapid change of power grid frequency regulation, and energy storage, as a new type of technology, has the ability of fast response and strong instantaneous power output, and becomes an important resource for assisting the frequency modulation of new power systems.

[0003] According to the time scale and capacity size of energy storage, energy storage can be divided into energy storage and power storage. However, a single energy storage method has gradually failed to meet all requirements, and therefore the combination of multiple energy storage methods has been widely applied. Although research on hybrid energy storage systems has made certain progress, current research is mostly focused on the power distribution strategy of hybrid energy storage systems participating in primary frequency modulation or secondary frequency modulation of thermal power units, and there is no research on the power distribution strategy of energy storage systems participating in primary and secondary frequency modulation at the same time. SUMMARY

[0004] The application aims to provide a hybrid energy storage power distribution method based on power grid frequency modulation demand, which can improve the accuracy and stability of frequency modulation and effectively reduce energy loss.

[0005] To achieve the above-mentioned purpose, the application provides the following solutions.

[0006] The application provides a hybrid energy storage power distribution method based on power grid frequency modulation demand, which comprises the following steps: acquiring 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 state of charge of each energy storage unit in a hybrid energy storage system; when the directions of the primary frequency modulation signal instruction and the secondary frequency modulation signal instruction are consistent, 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 working condition of the hybrid energy storage system according to the state of charge of each energy storage unit in the hybrid energy storage system; based on the working condition of the hybrid energy storage system, distributing power instructions to each energy storage unit according to the first total response instruction of the hybrid energy storage system, with the goal of prolonging the continuous adjustment capacity 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 of the hybrid energy storage system, and distributing initial power instructions to each energy storage unit according to the second total response instruction of the hybrid energy storage system; dynamically adjusting the initial power instructions of each energy storage unit by using a fuzzy controller according to the power grid frequency deviation; and determining the final power instructions of each energy storage unit according to the adjusted power instructions of each energy storage unit and the rated power of each energy storage unit.

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

[0008] The application provides a hybrid energy storage power distribution method based on power grid frequency modulation demand, for the two working conditions that the primary frequency modulation signal instruction and the secondary frequency modulation signal instruction are consistent or opposite, different power distribution strategies are formulated under the comprehensive consideration of the state of charge of each energy storage unit in the hybrid energy storage system, and the initial power instruction of each energy storage unit is dynamically adjusted by using a fuzzy controller, so that the power distribution is flexibly adjusted, the adaptability and flexibility of the strategy are significantly improved, the accuracy and stability of frequency modulation are greatly enhanced, and energy loss is effectively reduced. BRIEF DESCRIPTION OF DRAWINGS

[0009] In order to more clearly illustrate the technical solutions in the embodiments of the application or the related art, the drawings needed to be used in the embodiments will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0010] Figure 1 A flowchart of a hybrid energy storage power distribution method based on power grid frequency modulation demand provided by an embodiment of the application;

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

[0012] The technical solutions in the embodiments of the application will be described clearly and completely below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are only some of the embodiments of the application, not all. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the application.

[0013] In order to make the above-mentioned purposes, features and advantages of the application more obvious and easy to understand, the application will be further described in detail below with reference to the drawings and specific embodiments.

[0014] Power-type energy storage excels in applications requiring rapid response to frequent power demands due to its fast charging and discharging capabilities. In power system operation, it mainly undertakes frequency modulation tasks. Representative technologies include flywheel energy storage, supercapacitors, and superconducting magnetic energy storage. In contrast, energy-type energy storage is known for its high energy storage density and large storage capacity, making it suitable for applications requiring sustained and large energy input. In grid peak shaving and other long-term, large-capacity energy input scenarios, energy-type energy storage plays a crucial role. Representative technologies include 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 recombination on the real-time output power of the hybrid energy storage system, ensuring that each energy storage medium can undertake 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] Therefore, in order to determine the power allocation strategy of the energy storage system when participating in primary and secondary frequency modulation simultaneously, in an exemplary embodiment, as shown in Figure 1 a hybrid energy storage power allocation method based on grid frequency modulation demand is provided, comprising the following steps 101 to 107. Among them:

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

[0018] Step 102: When the directions of the primary frequency modulation signal instruction and the secondary frequency modulation signal instruction are consistent, determine the 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.

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

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

[0021] Step 105: When the directions of the primary frequency modulation signal instruction and the secondary frequency modulation signal instruction are opposite, take the primary frequency modulation signal instruction as the second total response instruction of the hybrid energy storage system, and allocate initial power instructions 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, dynamically adjust the initial power instructions of each energy storage unit using a fuzzy controller.

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

[0024] The steps 101 to 107 are implemented, and for the two working conditions that the primary frequency modulation signal instruction and the secondary frequency modulation signal instruction are consistent or opposite, different power distribution strategies are formulated in comprehensive consideration of the state of charge of each energy storage unit in the hybrid energy storage system, and the initial power instruction of each energy storage unit is dynamically adjusted by using the fuzzy controller, so as to flexibly adjust the power distribution, significantly improve the adaptability and flexibility of the strategy, greatly enhance the accuracy and stability of frequency modulation, and effectively reduce the energy loss.

[0025] In another exemplary embodiment of the present application, the state of charge of each energy storage unit in the hybrid energy storage system obtained in the step 101 is in the range of 0 to 1, indicating the size of the current storage capacity of the energy storage unit. The secondary frequency modulation signal instruction is specifically the grid secondary frequency modulation signal AGC (Automatic Generation Control) instruction. In addition to obtaining the primary frequency modulation signal instruction P1, the secondary frequency modulation signal instruction P2, the grid frequency deviation Δf and the state of charge of each energy storage unit in the hybrid energy storage system, the rated power of each energy storage unit can also be obtained. AGG , the load of the thermal power unit P g , the grid frequency deviation Δf and the state of charge of each energy storage unit in the hybrid energy storage system, the rated power of each energy storage unit can also be obtained.

[0026] The present application formulates different power distribution strategies according to whether the directions of the primary frequency modulation signal instruction and the secondary frequency modulation signal instruction are consistent. The two power distribution strategies are introduced respectively as follows.

[0027] (I) The power distribution strategy when the directions of the primary frequency modulation signal instruction and the secondary frequency modulation signal instruction 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 have the same action direction, the hybrid energy storage system simultaneously distributes power for primary and secondary frequency modulation. Since the secondary frequency modulation instruction signal is generally a step change, the thermal power unit will follow the AGC instruction signal to increase or decrease the load, and therefore the flywheel and the flow battery simultaneously respond to the secondary frequency modulation signal and the difference between the output P g of the thermal power unit and the primary signal instruction P1. Therefore, the calculation formula of the first total response instruction of the hybrid energy storage system in the step 102 is as follows:

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

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

[0031] In another example embodiment of the present application, to avoid overcharging and over-discharging problems and prolong the service life of the energy storage, the SOC states of the flywheel and the battery are considered when the hybrid energy storage system responds to the signal instruction P2, the SOC intervals of the flywheel and the battery are divided, and the working conditions of the hybrid energy storage system in different SOC combinations are determined. Then, the above step 103 can be replaced by steps 201-203:

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

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

[0034] Step 203: According to the state of charge of each energy storage unit in the hybrid energy storage system, determine the working condition of the hybrid energy storage system by using the correspondence between the state of charge combination and the working condition of the hybrid energy storage system.

[0035] In another example embodiment of the present application, when the hybrid energy storage system includes a flywheel energy storage and a full vanadium redox flow battery, the correspondence between the state of charge combination and the working condition of the hybrid energy storage system is as follows:

[0036] When the state of charge interval of the flywheel energy storage is [0.1, 0.3), and the state of charge interval of the full vanadium redox flow battery is [0.1, 0.3), the working condition of the hybrid energy storage system is S1.

[0037] When the state of charge interval of the flywheel energy storage is [0.3, 0.7), and the state of charge interval of the full vanadium redox flow battery is [0.1, 0.3), the working condition of the hybrid energy storage system is S2.

[0038] When the state of charge interval of the flywheel energy storage is [0.7, 0.9], and the state of charge interval of the full vanadium redox flow battery is [0.1, 0.3), the working condition of the hybrid energy storage system is S3.

[0039] When the state of charge interval of the flywheel energy storage is [0.1, 0.3), and the state of charge interval of the full vanadium redox flow battery is [0.3, 0.7), the working condition of the hybrid energy storage system is S4.

[0040] When the state of charge interval of the flywheel energy storage is [0.3, 0.7), and the state of charge interval of the full vanadium redox flow battery is [0.3, 0.7), the working condition of the hybrid energy storage system is S5.

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

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

[0043] When the state of charge interval of the flywheel energy storage is [0.1, 0.3) and the state of charge interval of the all-vanadium redox flow battery is [0.7, 0.9], the working condition of the hybrid energy storage system is S7.

[0044] When the state of charge interval of the flywheel energy storage is [0.1, 0.3) and the state of charge interval of the all-vanadium redox flow battery is [0.7, 0.9], the working condition of the hybrid energy storage system is S7.

[0045] The correspondence between the state of charge combination and the working condition of the hybrid energy storage system can be seen from Table 1.

[0046] Table 1: Working condition division of the hybrid energy storage system

[0047]

[0048]

[0049] In another exemplary embodiment of the present application, the power instruction requirement is comprehensively considered, the flywheel energy storage SOC is preferentially responded by the flywheel energy storage when the flywheel energy storage SOC is suitable for responding to the instruction, the flywheel energy storage SOC is preferentially responded by the battery energy storage when the flywheel energy storage SOC is too high or too low, and the hybrid energy storage system SOC is uniformly too high or too low, and the dynamic residual capacity proportion distribution strategy is used for responding, so as to achieve the purpose of prolonging the continuous adjustment capability of the hybrid energy storage system. The above step 104 can be replaced by the following steps 301-303:

[0050] Step 301: when the first total response instruction is less than 0 and the working condition of the hybrid energy storage system is S4, S7 or S8, the power instruction is allocated to each energy storage unit according to the formula P1=P1max*P1 / P1max+P2 / P2max f P1 is the flywheel energy storage power instruction, P1max is the flywheel energy storage rated power, v P2 is the all-vanadium redox flow battery power instruction, P2max is the all-vanadium redox flow battery rated power. fm P1 is the flywheel energy storage power instruction, P1max is the flywheel energy storage rated power, vm P2 is the all-vanadium redox flow battery power instruction, P2max is the all-vanadium redox flow battery rated power.

[0051] If the first total response instruction is less than 0, the hybrid energy storage system is charged. When the hybrid energy storage system is in the working condition of S4, S7 or S8, compared with the SOC of the battery, the flywheel SOC is lower, so the flywheel is preferentially charged, and the battery is supplemented.

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

[0053] When the hybrid energy storage system is in S2, S3 or S6, the SOC of the battery is lower than that of the flywheel, so the battery is preferentially charged 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 is in S1, S5 or S9, the power instruction for each energy storage unit is allocated according to the formula f SOCf is the state of charge of the flywheel energy storage, SOC v SOCv is the state of charge of the all-vanadium redox flow battery.

[0055] When the hybrid energy storage system is in S1, S5 or S9, the SOC of the flywheel and the battery is similar, so

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

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

[0058] Step 401: When the first total response instruction is greater than 0 and the hybrid energy storage system is in S2, S3 or S6, the power instruction for each energy storage unit is allocated according to the formula f Pf is the flywheel energy storage power instruction, P v Pv is the all-vanadium redox flow battery power instruction, P2 is the first total response instruction, P fm Pf is the flywheel energy storage rated power, P vm Pv is the all-vanadium redox flow battery rated power.

[0059] If the first total response instruction is greater than 0, the hybrid energy storage system is discharged. When the hybrid energy storage system is in S2, S3 or S6, the SOC of the flywheel is higher than that of the battery, so the flywheel is preferentially discharged and the battery is supplemented.

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

[0061] When the hybrid energy storage system is in S4, S7 or S8, the SOC of the battery is higher than that of the flywheel, so the battery is preferentially discharged 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 is in S1, S5 or S9, the power instruction for each energy storage unit is allocated according to the formula , wherein SOC f is the state of charge of the flywheel energy storage, SOC v is the state of charge of the all-vanadium redox flow battery.

[0063] When the hybrid energy storage system is in S1, S5 or S9, the SOC of the flywheel and the battery is not much different, so a strategy of dynamically adjusting the output of the flywheel and the battery according to the SOC state is adopted to prolong 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 modulation instruction and the secondary frequency modulation instruction conflict, i.e., the directions of action of the two are opposite, the grid evaluation rules stipulate that when the direction of action of the primary frequency modulation of the unit is opposite to the direction of the AGC instruction, the unit should set the primary frequency modulation as the priority, and since the primary frequency modulation can quickly stabilize the frequency of the power system, it can effectively prevent the risk of system instability or even collapse that may be caused by a large deviation of the frequency from the normal value, and the primary frequency modulation instruction should also be given priority. Therefore, the total response instruction of the flywheel and the flow battery is:

[0066] P2=P1

[0067] In order to more accurately respond to such conflicts of frequency modulation instructions, fully considering the current operating conditions and actual needs of the grid, when the hybrid energy storage system includes a flywheel energy storage and an all-vanadium redox flow battery, first, the SOC of the flywheel and the battery is divided into working conditions to determine the initial output instruction P f1 and P v1 of the flywheel and the battery, and this process is the same as the power allocation strategy when the primary frequency modulation signal instruction and the secondary frequency modulation signal instruction are in the same direction. Then, step 105 above allocates the initial power instruction for each energy storage unit according to the second total response instruction of the hybrid energy storage system, which can be replaced by steps 501-502 as follows:

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

[0069] Step 502: Based on the working condition of the hybrid energy storage system, allocate the power instruction for each energy storage unit according to the second total response instruction of the hybrid energy storage system, with the goal of prolonging the continuous regulation capacity of the hybrid energy storage system.

[0070] In another exemplary embodiment of this application, compared to the flywheel energy storage system, the instantaneous charge and discharge power capability of the flow battery is insufficient, and frequent charge and discharge will lead to a rapid decline in the lifespan of the flow battery. Considering the introduction of a fuzzy controller to further dynamically adjust the output of each component of the hybrid energy storage system, the flywheel energy storage system responds more to short-term, low-power adjustment commands, thereby improving the overall lifespan of the hybrid energy storage system. The core of dynamic adjustment lies in the initial output command P of the flow battery. v1 Multiply by the battery output adjustment coefficient T, which is flexibly adjusted according to changes in system frequency.

[0071] Because the flywheel has rapid charging and discharging capabilities and can quickly respond to frequent power demands, when |Δf| is small, and If the frequency is too high, T should be reduced to decrease the output of battery energy storage. Flywheel energy storage should then take on more frequency regulation tasks and respond quickly to balance grid frequency fluctuations. When the load is relatively small, the load fluctuations are smooth, the frequency regulation requirement decreases, and the output of the battery storage is increased appropriately to coordinate the output distribution between the flywheel and the battery storage. When |Δf| is large, T should be increased to take advantage of the large energy capacity of the battery storage. Therefore, the overall control strategy of the hybrid energy storage system is as follows: Figure 2 As shown.

[0072] Design a two-input, single-output fuzzy controller for the battery output adjustment coefficient T that needs to be adjusted. (Frequency change rate) The fuzzy universe of discourse for is [-0.01, 0.01], and the fuzzy subset is {NB(negative large), NS(negative small), NZ(negative zero), PZ(positive zero), PS(positive small), PB(positive large)}; the fuzzy universe of discourse for Δf is [-0.1, 0.1], and the fuzzy subset is {NB(negative large), NS(negative small), NZ(negative zero), PZ(positive zero), PS(positive small), PB(positive large)}; the fuzzy universe of discourse for the battery output adjustment coefficient T is [0, 1], and the fuzzy subset is {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 vanadium redox flow battery, step 106 above 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, the initial power instruction of each energy storage unit is adjusted according to the formula The initial power instruction of the flywheel energy storage is P f1 The initial power instruction of the flywheel energy storage is P v1 The initial power instruction of the flywheel energy storage is P f,T The adjusted power instruction of the flywheel energy storage is P v,T The adjusted power instruction of the flywheel energy storage is P

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

[0079]

[0080] The final power instruction of the flywheel energy storage is P f The final power instruction of the flywheel energy storage is P v The final power instruction of the flywheel energy storage is P f,T The adjusted power instruction of the flywheel energy storage is P v,T The adjusted power instruction of the flywheel energy storage is P fm The rated power of the flywheel energy storage is P vm The rated power of the flywheel energy storage is P

[0081] In another exemplary embodiment of the present application, when the hybrid energy storage system comprises the flywheel energy storage and the all-vanadium redox 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 step 107 above can also be:

[0082]

[0083] The final power instruction of the flywheel energy storage is P f The final power instruction of the flywheel energy storage is P v The final power instruction of the flywheel energy storage is P f,T The adjusted power instruction of the flywheel energy storage is P v,T The adjusted power instruction of the flywheel energy storage is P fm The rated power of the flywheel energy storage is P vm The rated power of the flywheel energy storage is P

[0084] The application proposes a power distribution strategy considering that the hybrid energy storage participates in primary and secondary frequency modulation, and parameters are self-adjusted based on system characteristics, so that the power distribution strategy can be flexibly adjusted according to the actual demand and operating state of the power grid, especially in the power grid with a high proportion of new energy power generation, to handle higher frequency and larger power frequency modulation demand, improve overall efficiency and reduce energy loss.

[0085] The application ingeniously combines the respective advantages of energy storage and power storage, and innovatively proposes a hybrid energy storage parameter self-adjusting control strategy for power grid frequency modulation demand. Not only does it comprehensively consider the power distribution problem of primary and secondary frequency modulation, but also realizes close cooperation between the two. By comprehensively considering the SOC of the energy storage system, according to the actual demand and operating state of the power grid, using the output distribution strategy and dynamic parameter adjustment method for different working conditions, the power distribution is flexibly adjusted, the adaptability and flexibility of the strategy are significantly improved, the accuracy and stability of frequency modulation are greatly enhanced, and energy loss is effectively reduced, providing strong support for the stability of the power grid frequency.

[0086] The technical features of the above embodiments can be combined in any way. To make the description concise, not all possible combinations of the technical features in the above embodiments are described, but as long as the combinations of the technical features do not exist contradictions, they should be considered as the scope of the present application.

[0087] The principles and implementation modes of the application are described by applying specific examples in this paper, and the above embodiment descriptions are only used to help understand the method and its core idea; at the same time, for those skilled in the art, according to the idea of the application, the specific implementation mode and application range will be changed. In conclusion, the content of the specification should not be understood as a limitation of the application.

Claims

1. A hybrid energy storage power distribution method based on grid frequency regulation demand, characterized in that, The application relates to a power distribution method for a hybrid energy storage system, and belongs to the field of power distribution. Real-time acquisition of primary frequency modulation signal instructions, secondary frequency modulation signal instructions, thermal power unit load, power grid frequency deviation and state of charge of each energy storage unit in the hybrid energy storage system; the hybrid energy storage system comprises a flywheel energy storage and a full vanadium redox battery; 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 thermal power unit load, and a calculation formula of the first total response instruction of the hybrid energy storage system is P2 = P AGC - P g + P1; wherein P2 is the first total response instruction, P AGG is the secondary frequency modulation signal instruction, P g is the thermal power unit load, and P1 is the primary frequency modulation signal instruction. According to the state of charge of each energy storage unit in the hybrid energy storage system, the working condition of the hybrid energy storage system is determined; Based on the working condition of the hybrid energy storage system, power instructions are distributed to each energy storage unit according to the first total response instruction of the hybrid energy storage system, with the target of prolonging the continuous adjustment capability of the hybrid energy storage system; When the directions of the primary frequency modulation signal instructions and the secondary frequency modulation signal instructions are opposite, the primary frequency modulation signal instructions are taken as the second total response instruction of the hybrid energy storage system, and initial power instructions are distributed to each energy storage unit according to the second total response instruction of the hybrid energy storage system; According to the power grid frequency deviation, a fuzzy controller is used to dynamically adjust the initial power instructions of each energy storage unit; specifically, the real-time acquired power grid frequency deviation and frequency change rate are input into the fuzzy controller to obtain a real-time battery output adjustment coefficient; According to the real-time battery output adjustment coefficient, according to the formula The initial power instruction of each energy storage unit is dynamically adjusted; wherein, P f1 is the initial power instruction of the flywheel energy storage, P v1 is the initial power instruction of the all-vanadium redox flow battery, T is the battery output adjustment coefficient, P f,T is the adjusted power instruction of the flywheel energy storage, P v,T is the adjusted power instruction of the all-vanadium redox flow battery; According to the adjusted power instruction 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; if the second total response instruction is less than 0, the calculation formula of the final power instruction of each energy storage unit is: In the formula, P' is the final power instruction of the flywheel energy storage, P' is the final power instruction of the all-vanadium redox flow battery, P is the rated power of the flywheel energy storage, P is the rated power of the all-vanadium redox flow battery, and P is the final power instruction of each energy storage unit. f v fm vm If the second total response instruction is greater than 0, the calculation formula of the final power instruction of each energy storage unit is: ​​​ 2. The method of claim 1, wherein, According to the state of charge of each energy storage unit in the hybrid energy storage system, the working condition of the hybrid energy storage system is determined, specifically 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 interval of each energy storage unit is combined in any way to obtain a plurality of state of charge combinations; The corresponding relationship between the state of charge combinations and the working condition of the hybrid energy storage system is determined; According to the state of charge of each energy storage unit in the hybrid energy storage system, the corresponding relationship between the state of charge combinations and the working condition of the hybrid energy storage system is used to determine the working condition of the hybrid energy storage system.

3. The method of claim 2, wherein, The corresponding relationship between the state of charge combinations and the working condition of the hybrid energy storage system is as follows: When the state of charge interval of the flywheel energy storage is [0.1, 0.3) and the state of charge interval of the full vanadium redox battery is [0.1, 0.3), the working condition of the hybrid energy storage system is S1; When the state of charge interval of the flywheel energy storage is [0.3, 0.7) and the state of charge interval of the full vanadium redox battery is [0.1, 0.3), the working condition of the hybrid energy storage system is S2; When the state of charge interval of the flywheel energy storage is [0.7, 0.9] and the state of charge interval of the full vanadium redox battery is [0.1, 0.3), the working condition of the hybrid energy storage system is S3; When the state of charge interval of the flywheel energy storage is [0.1, 0.3) and the state of charge interval of the full vanadium redox battery is [0.3, 0.7), the working condition of the hybrid energy storage system is S4; When the state of charge interval of the flywheel energy storage is [0.3, 0.7) and the state of charge interval of the full vanadium redox battery is [0.3, 0.7), the working condition of the hybrid energy storage system is S5; When the state of charge interval of the flywheel energy storage is [0.7, 0.9] and the state of charge interval of the full vanadium redox battery is [0.3, 0.7), the working condition of the hybrid energy storage system is S6; When the state of charge interval of the flywheel energy storage is [0.1, 0.3) and the state of charge interval of the full vanadium redox battery is [0.7, 0.9], the working condition of the hybrid energy storage system is S7. When the state of charge interval of the flywheel is [0.3, 0.7) and the state of charge interval of the all-vanadium redox flow battery is [0.7, 0.9], the working condition of the hybrid energy storage system is S8. When the state of charge interval of the flywheel is [0.7, 0.9] and the state of charge interval of the all-vanadium redox flow battery is [0.7, 0.9], the working condition of the hybrid energy storage system is S9.

4. The hybrid energy storage power distribution method based on grid frequency regulation demand according to claim 3, characterized in that, Based on the working condition 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, with the objective of prolonging the continuous adjustment capability of the hybrid energy storage system, and specifically including: When the first total response instruction is less than 0 and the hybrid energy storage system working condition is S4, S7 or S8, the power instruction of each energy storage unit is allocated according to the formula P f P v P When the first total response instruction is less than 0 and the hybrid energy storage system working condition is S2, S3 or S6, the power instruction for each energy storage unit is allocated according to the formula is allocated to each energy storage unit. When the first total response instruction is less than 0 and the hybrid energy storage system working condition is S1, S5 or S9, the power instruction for each energy storage unit is allocated according to the formula SOC is the state of charge of each energy storage unit f SOC is the state of charge of the flywheel energy storage v SOC is the state of charge of the all-vanadium redox flow battery 5. The hybrid energy storage power distribution method based on grid frequency regulation demand according to claim 3 or 4, characterized in that, Based on the working condition 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, with the objective of prolonging the continuous adjustment capability of the hybrid energy storage system, and specifically including: When the first total response instruction is greater than 0 and the hybrid energy storage system working condition is S2, S3 or S6, the power instruction of each energy storage unit is allocated according to the formula P is the power instruction of each energy storage unit, P f P is the flywheel energy storage power instruction, P v P is the all-vanadium redox flow battery power instruction; When the first total response instruction is greater than 0 and the hybrid energy storage system working condition is S4, S7 or S8, the power instruction for each energy storage unit is allocated according to the formula allocating the power instruction for each energy storage unit; When the first total response instruction is greater than 0 and the hybrid energy storage system working condition is S1, S5 or S9, the power instruction for each energy storage unit is allocated according to the formula SOC f SOC v SOC 6. The method of claim 1, wherein, According to the second total response instruction of the hybrid energy storage system, initial power instructions are allocated to each energy storage unit, and specifically including: According to the state of charge of each energy storage unit in the hybrid energy storage system, the working condition of the hybrid energy storage system is determined; Based on the working condition 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, with the objective of prolonging the continuous adjustment capability of the hybrid energy storage system.

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