A grid frequency control method and system based on a liquid hydrogen superconducting synergistic energy storage system

Abstract

This invention discloses a method and system for participating in grid frequency control using liquid hydrogen superconducting co-existing energy storage, belonging to the field of electrical engineering. The method includes: when a grid frequency event occurs, obtaining the maximum value of the system frequency change rate based on the instantaneous frequency change rate of the grid; determining the active power output control quantity of the liquid hydrogen superconducting co-existing energy storage system based on the maximum value of the system frequency change rate and the power response coefficient. Using the charging and discharging dynamic characteristics of the liquid hydrogen superconducting co-existing energy storage system and the system's energy storage capacity as operational constraints, the system's output is controlled according to a time-series tiered response control strategy. The superconducting magnetic energy storage system's rapid power response satisfies the active power output control quantity; after exceeding the set output duration of the superconducting magnetic energy storage system, the hydrogen energy storage system coordinates its output to compensate for the active power output control quantity deficit caused by the superconducting magnetic energy storage system's load reduction. This effectively coordinates the active power output of various devices within the system based on the operating characteristics of the liquid hydrogen superconducting co-existing energy storage system, improving grid frequency stability.

Description

Technical Field

[0001] This invention belongs to the field of electrical engineering, and more specifically, relates to a power grid frequency control method and system based on a liquid hydrogen superconducting synergistic energy storage system. Background Technology

[0002] With the integration of a high proportion of fluctuating renewable energy sources, grid frequency stability is under greater pressure, increasing the demand for flexible resources to mitigate real-time active power imbalances. New energy storage technologies, capable of spatiotemporal energy transfer, are becoming crucial players in maintaining grid frequency stability. However, among existing new energy storage technologies, power-type energy storage, while capable of delivering large amounts of active power in a short period, is limited by its capacity and cannot provide sustained frequency support. Generally, it is only suitable for inertial support and primary frequency regulation, and there is a risk of a secondary frequency drop when it exits regulation. Energy-type energy storage can provide large-scale, long-term active power support during frequency events, but its response speed is slower than that of power-type energy storage. It typically participates in primary and secondary frequency regulation, potentially leading to a rapid drop in system frequency in the initial stages of a frequency event. Based on the respective frequency regulation characteristics of power-type and energy-type energy storage, the application of hybrid energy storage combining these two types in frequency control can help improve the ability of new energy storage technologies to support system frequency and ensure grid frequency stability.

[0003] Liquid hydrogen superconducting co-existing energy storage combines superconducting magnetic energy storage (power-type) with hydrogen energy storage (energy-type). Utilizing the characteristics of superconducting coils and liquid hydrogen, it achieves the fusion of matter and energy during the storage process, demonstrating significant potential for grid applications. Currently, in grid-oriented applications, liquid hydrogen superconducting co-existing energy storage systems primarily leverage their rapid response capabilities to achieve power system power smoothing and optimized operation, but lack real-time control strategies for grid frequency disturbances. However, there are still challenges in integrating liquid hydrogen superconducting co-existing energy storage into grid frequency control: First, the different technical characteristics of the superconducting magnetic energy storage, electrolyzer, and hydrogen fuel cell within the liquid hydrogen superconducting co-existing energy storage system necessitate coordinating the active power output of the energy storage in response to grid frequency events; second, balancing the frequency regulation characteristics and cost of liquid hydrogen superconducting co-existing energy storage requires a frequency control strategy that fully utilizes the regulation speed of power-type energy storage while also appropriately leveraging the energy storage's frequency regulation capacity to enhance regulation economy.

[0004] Furthermore, the dynamic characteristics of charging and discharging of liquid hydrogen superconducting co-existing energy storage systems and the operational constraints of energy storage systems have not been fully considered in the design of grid frequency control strategies. This results in a gap between frequency control and the actual operational requirements of the energy storage system, making it difficult to achieve coordinated operation of various devices within the co-existing energy storage system and restricting the application of liquid hydrogen superconducting co-existing energy storage systems in grid frequency control. Summary of the Invention

[0005] To address the shortcomings of related technologies, the present invention aims to provide a grid frequency control method and apparatus based on a liquid hydrogen superconducting synergistic energy storage system. This invention addresses the problem that existing technologies do not consider the charging and discharging dynamic characteristics of the liquid hydrogen superconducting synergistic energy storage system and the operational constraints of the energy storage system in grid frequency control, resulting in a gap between frequency control and the actual operational requirements of the energy storage system.

[0006] To achieve the above objectives, in a first aspect, the present invention provides a grid frequency control method based on a liquid hydrogen superconducting synergistic energy storage system, comprising:

[0007] S100. When a grid frequency event occurs, obtain the maximum value of the system frequency change rate based on the instantaneous frequency change rate of the grid, and determine the active power output control quantity of the liquid hydrogen superconducting co-existing energy storage system based on the maximum value of the system frequency change rate and the power response coefficient.

[0008] S200. Using the dynamic characteristics of the charge-discharge cycle and the system energy storage capacity of the liquid hydrogen superconducting synergistic energy storage system as operational constraints, and according to a time-series tiered response control strategy, the active power output of the superconducting magnetic energy storage in the liquid hydrogen superconducting synergistic energy storage system is controlled to meet the active power output control amount. After the set duration of superconducting magnetic energy storage output is exceeded, the active power output of the superconducting magnetic energy storage is controlled to gradually decrease over time. At the same time, the active power output of the hydrogen energy storage in the liquid hydrogen superconducting synergistic energy storage system is controlled to compensate for the shortfall in active power output control amount caused by the load reduction of the superconducting magnetic energy storage, so that the two cooperate with each other to stabilize the grid frequency.

[0009] Optionally, in the event of a power grid frequency event, the following may also be included:

[0010] The real-time frequency change rate of the power grid is obtained, and the sign of the real-time frequency change rate is compared with the over-frequency response event action threshold and the under-frequency response event action threshold, respectively, to determine whether the power grid frequency event is an over-frequency event or an under-frequency event. If the over-frequency response event action threshold / under-frequency response event action threshold is exceeded, it is determined to be an over-frequency event / under-frequency event, and an event trigger signal is generated to trigger the corresponding over-frequency event / under-frequency event.

[0011] Optionally, when a power grid frequency event occurs, obtaining the maximum or minimum system frequency change rate based on the instantaneous frequency change rate of the power grid includes:

[0012] Real-time frequency measurements are performed at measurement points on the power grid, and the rate of frequency change is obtained by differentiating the real-time frequency measurements. The event is compared with the over-frequency response event action threshold and the under-frequency response event action threshold to determine whether the power grid frequency event is an over-frequency event or an under-frequency event; the logical relationship for generating the event trigger signal is as follows:

[0013]

[0014] Among them, SGL uf ROCOF is the trigger signal for the underfrequency response event. uf The action threshold for under-frequency response events; SGL of ROCOF is the overclocking response event trigger signal. of The threshold for overclocking response events;

[0015] For underfrequency response events, obtain the minimum frequency change rate from historical events, compare it with the current frequency change rate, and use the minimum value to calculate the active power output control quantity.

[0016] ΔP uf =-K re ·SGL uf ·min(ROCOF·SGL uf ,ROCOF min_pre )

[0017] Wherein, ΔP uf K is the active power output control quantity for the underfrequency response event; re ROCOF is the power response coefficient. min_pre This represents the minimum rate of frequency change among historical under-frequency response events.

[0018] For overclocking response events, obtain the maximum value of the frequency change rate in historical events, compare it with the current frequency change rate, and use the maximum value to calculate the active power output control quantity:

[0019] ΔP of =-K re ·SGL of ·max(ROCOF·SGL of ,ROCOF max_pre )

[0020] Wherein, ΔP of ROCOF is the active power output control quantity for overclocking response events. max_pre This represents the maximum rate of frequency change in historical overclocking response events.

[0021] Optionally, the operational constraints include: superconducting magnetic energy storage constraints and hydrogen energy storage liquid level constraints;

[0022] The confinement for superconducting magnetic energy storage is:

[0023]

[0024] Wherein, ΔSOC SMES_min This represents the lower limit of the change in state of charge (ΔSOC) in superconducting magnetic energy storage. SMES_max The upper limit of the change in the state of charge of superconducting magnetic energy storage; ΔP SMESE represents the active power response of superconducting magnetic energy storage. SMES For superconducting magnetic energy storage capacity; T SL The output time is limited by the superconducting magnetic energy storage;

[0025] The hydrogen storage liquid level constraint is:

[0026]

[0027] Wherein, ΔSOC H_min This represents the lower limit of the change in state of charge (SOC) in hydrogen energy storage; ΔSOC H_max This represents the upper limit of the change in the state of charge of hydrogen energy storage; ΔP H The active power response of hydrogen storage is given by the active power response ΔP of the electrolyzer. EL With the active power response ΔP of hydrogen fuel cells FC Composition; E H For hydrogen energy storage capacity; K ev The coefficient of liquid hydrogen evaporation caused by superconducting magnetic energy storage heating; T HL The output time is limited by hydrogen storage.

[0028] Optionally, the operational constraints also include:

[0029] The dynamic characteristics constraints of the charge and discharge of the liquid hydrogen superconducting synergistic energy storage system are as follows:

[0030]

[0031] Among them, K SMES T is the proportionality constant of superconducting magnetic energy storage; SMES ΔP is the response time constant of superconducting magnetic energy storage. S_c K is the active power output control quantity for superconducting magnetic energy storage. EL T is the proportionality constant of the electrolytic cell; EL ΔP is the response time constant of the electrolyzer; EL_c K is the active power output control quantity of the electrolytic cell. FC T is the proportionality constant of the hydrogen fuel cell; FC ΔP is the response time constant of the hydrogen fuel cell; FC_c This refers to the active power output control quantity of hydrogen fuel cells.

[0032] Optionally, the active power output control quantity ΔP of the superconducting magnetic energy storage S_c :

[0033]

[0034] Among them, K S_up K represents the superconducting magnetic energy storage output loading rate. S_d For superconducting magnetic energy storage output load reduction rate; P S_max This represents the upper limit of superconducting magnetic energy storage output; Tset The set duration of superconducting magnetic energy storage output is used to support the power system frequency before hydrogen energy storage is activated;

[0035] The active power output control quantity ΔP of the hydrogen energy storage H_c :

[0036]

[0037] Where H represents an electrolyzer (EL) or a hydrogen fuel cell (FC), and K... H_up For hydrogen energy storage output loading rate; K H_d For hydrogen storage output load reduction rate; P H_max This represents the upper limit of hydrogen storage power output.

[0038] Optionally, the timing-based tiered response control strategy satisfies the following constraints:

[0039] T set ≥T HS

[0040] ΔP H_c =0,T set ≥T HL

[0041] Among them, the duration of superconducting magnetic energy storage output T set Longer than the start-up time T of hydrogen energy storage HS If the superconducting magnetic energy storage output duration T is reached... set Before, hydrogen storage power output time T HS If the limit has been reached, the hydrogen storage power output will not be activated.

[0042] In a second aspect, the present invention also provides a power grid frequency control system based on a liquid hydrogen superconducting synergistic energy storage system, comprising: a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to perform the method provided in any of the first aspects.

[0043] Thirdly, the present invention also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the method provided in any of the first aspects.

[0044] Compared with the prior art, the above-described technical solutions conceived in this invention can achieve the following results.

[0045] Beneficial effects:

[0046] 1. This invention provides a grid frequency control method based on a liquid hydrogen superconducting synergistic energy storage system. When a grid frequency event occurs, the active power output control quantity of the liquid hydrogen superconducting synergistic energy storage system is calculated based on the maximum and minimum values ​​of the system frequency change rate. Taking into full account the dynamic charging and discharging characteristics of the liquid hydrogen superconducting synergistic energy storage system and the operational constraints of the system's energy storage capacity, and based on the instantaneous response of superconducting magnetic energy storage and the need for a certain start-up time for hydrogen energy storage, a time-sequential response control strategy is formulated to regulate the grid frequency. This achieves coordinated operation of the various devices within the power-type (superconducting magnetic energy storage) and energy-type (hydrogen storage) synergistic energy storage systems, improving the grid frequency control effect. Especially during the phase when superconducting magnetic energy storage withdraws from the system, the output of hydrogen energy storage is coordinated to compensate for the system power control deficit, ensuring continuous and coordinated output between superconducting magnetic energy storage and hydrogen energy storage, reducing the risk of secondary frequency drops, and improving the grid frequency regulation capability. This also reduces the problem of insufficient response capability and poor regulation speed of traditional frequency regulation resources such as thermal power in the grid.

[0047] 2. The present invention provides a grid frequency control method based on a liquid hydrogen superconducting synergistic energy storage system. Facing the complex and variable underfrequency and overfrequency response requirements of the power grid, the method obtains the corresponding active power output control quantity of the liquid hydrogen superconducting synergistic energy storage system based on the measurement of the grid frequency change rate. This adapts to the output characteristics of the liquid hydrogen superconducting synergistic energy storage system, enabling the effective participation of the liquid hydrogen superconducting synergistic energy storage system in frequency regulation under bidirectional fluctuations of unbalanced power in the real power grid. Based on a time-sequenced response control strategy, the active power output control quantities of the superconducting magnetic energy storage and hydrogen energy storage in the liquid hydrogen superconducting synergistic energy storage system are finely adjusted, achieving inter-device coordination under different output characteristics and regulation rates.

[0048] 3. The present invention provides a power grid frequency control method based on a liquid hydrogen superconducting co-existing energy storage system. In view of the current situation where the high proportion of new energy access in the new power system leads to the decrease of system inertia, the method controls the liquid hydrogen superconducting co-existing energy storage system, a large-capacity flexible energy storage system, to provide rapid active power support. This is conducive to the engineering promotion and application of the liquid hydrogen superconducting co-existing energy storage system and fully leverages the beneficial role of new energy storage technology in participating in frequency auxiliary services and improving the frequency security of the power grid. Attached Figure Description

[0049] Figure 1 A flowchart of a power grid frequency control method based on a liquid hydrogen superconducting syn-energy storage system provided in an embodiment of the present invention;

[0050] Figure 2 A power grid system architecture diagram for connecting liquid hydrogen superconducting co-existing energy storage;

[0051] Figure 3 A comparison chart of the control effects of different energy storage configurations participating in grid frequency control under frequency events;

[0052] Figure 4 A comparison chart of the control effects of different energy storage configurations participating in grid frequency control under frequency events on the rate of frequency change of the grid system.

[0053] Figure 5 This is a comparison chart showing the output performance of a thermal power unit participating in grid frequency regulation under different energy storage configurations during frequency events. Detailed Implementation

[0054] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0055] The following description, in conjunction with a preferred embodiment, illustrates the content involved in the above embodiments.

[0056] Example 1

[0057] like Figure 1 As shown, this invention provides a grid frequency control method based on a liquid hydrogen superconducting synergistic energy storage system, comprising:

[0058] S100. When a grid frequency event occurs, obtain the maximum value of the system frequency change rate based on the instantaneous frequency change rate of the grid, and determine the active power output control quantity of the liquid hydrogen superconducting co-existing energy storage system based on the maximum value of the system frequency change rate and the power response coefficient.

[0059] S200. Using the dynamic characteristics of the charge-discharge cycle and the system energy storage capacity of the liquid hydrogen superconducting synergistic energy storage system as operational constraints, and according to a time-series tiered response control strategy, the active power output of the superconducting magnetic energy storage in the liquid hydrogen superconducting synergistic energy storage system is controlled to meet the active power output control amount. After the set duration of superconducting magnetic energy storage output is exceeded, the active power output of the superconducting magnetic energy storage is controlled to gradually decrease over time. At the same time, the active power output of the hydrogen energy storage in the liquid hydrogen superconducting synergistic energy storage system is controlled to compensate for the shortfall in active power output control amount caused by the load reduction of the superconducting magnetic energy storage, so that the two cooperate with each other to stabilize the grid frequency.

[0060] An event triggering mechanism for liquid hydrogen superconducting co-existing energy storage to participate in grid frequency control is designed based on instantaneous frequency change rate measurement. The grid frequency events include over-frequency events and under-frequency events. When a grid frequency event occurs, the specific event triggering mechanism includes: acquiring the real-time frequency change rate of the grid, and comparing it with the over-frequency response event action threshold and the under-frequency response event action threshold, respectively, based on the sign of the real-time frequency change rate; if the corresponding over-frequency response event action threshold / under-frequency response event action threshold is exceeded, an event triggering signal is generated to trigger the corresponding over-frequency event / under-frequency event.

[0061] To ensure the effectiveness of liquid hydrogen superconducting co-storage in grid frequency control, it is first necessary to collect and determine the equipment parameters and operating characteristic parameters of the liquid hydrogen superconducting co-storage in advance, specifically including: the upper limit of superconducting magnetic energy storage output P. S_max Energy storage capacity E SMES Superconducting magnetic energy storage proportionality constant K SMES Superconducting magnetic energy storage response time constant T SMES The liquid hydrogen evaporation coefficient K caused by superconducting magnetic energy storage heating ev Electrolytic cell output limit P EL_max Electrolytic cell proportionality constant K EL Electrolytic cell response time constant T EL The upper limit of hydrogen fuel cell output P FC_max Electrolytic cell proportionality constant K FC Electrolytic cell response time constant T FC Hydrogen storage start-up time T HS Hydrogen storage capacity E H Based on the grid capacity and corresponding frequency safety standards, and considering the parameters and operating characteristics of the energy storage equipment, set appropriate over-frequency and under-frequency response event thresholds (ROCOF). of With ROCOF uf Power response coefficient K re .

[0062] Optionally, when a power grid frequency event occurs, obtaining the maximum or minimum system frequency change rate based on the instantaneous frequency change rate of the power grid includes:

[0063] Real-time frequency measurements are performed at measurement points on the power grid, and the rate of frequency change is obtained by differentiating the real-time frequency measurements. The event is compared with the over-frequency response event action threshold and the under-frequency response event action threshold to determine whether the power grid frequency event is an over-frequency event or an under-frequency event; the logical relationship for generating the event trigger signal is as follows:

[0064]

[0065] Among them, SGL ufROCOF is the trigger signal for the underfrequency response event. uf The action threshold for under-frequency response events; SGL of ROCOF is the overclocking response event trigger signal. of The threshold for overclocking response events;

[0066] For underfrequency response events, obtain the minimum frequency change rate from historical events, compare it with the current frequency change rate, and use the minimum value to calculate the active power output control quantity.

[0067] ΔP uf =-K re ·SGL uf ·min(ROCOF·SGL uf ,ROCOF min_pre )

[0068] Wherein, ΔP uf K is the active power output control quantity for the underfrequency response event; re ROCOF is the power response coefficient. min_pre This represents the minimum rate of frequency change among historical under-frequency response events.

[0069] For overclocking response events, obtain the maximum value of the frequency change rate in historical events, compare it with the current frequency change rate, and use the maximum value to calculate the active power output control quantity:

[0070] ΔP of =-K re ·SGL of ·max(ROCOF·SGL of ,ROCOF max_pre )

[0071] Wherein, ΔP of ROCOF is the active power output control quantity for overclocking response events. max_pre This represents the maximum rate of frequency change in historical overclocking response events.

[0072] Based on the event triggering mechanism, determine whether the frequency event occurring in the current power grid is an over-frequency event or an under-frequency event, obtain the maximum value of the system frequency change rate corresponding to the corresponding frequency event, and calculate the active power output control quantity required by the power grid in combination with the power response coefficient.

[0073] Optionally, the operational constraints include: superconducting magnetic energy storage constraints and hydrogen energy storage liquid level constraints;

[0074] Superconducting magnetic energy storage confinement:

[0075]

[0076] Wherein, ΔSOC SMES_minThis represents the lower limit of the change in state of charge (ΔSOC) in superconducting magnetic energy storage. SMES_max The upper limit of the change in the state of charge of superconducting magnetic energy storage; ΔP SMES E represents the active power response of superconducting magnetic energy storage. SMES For superconducting magnetic energy storage capacity; T SL The output time is limited by the superconducting magnetic energy storage;

[0077] Hydrogen storage liquid level constraint:

[0078]

[0079] Wherein, ΔSOC H_min This represents the lower limit of the change in state of charge (SOC) in hydrogen energy storage; ΔSOC H_max This represents the upper limit of the change in the state of charge of hydrogen energy storage; ΔP H The active power response of hydrogen storage is given by the active power response ΔP of the electrolyzer. EL With the active power response ΔP of hydrogen fuel cells FC Composition; E H For hydrogen energy storage capacity; K ev The coefficient of liquid hydrogen evaporation caused by superconducting magnetic energy storage heating; T HL The output time is limited by hydrogen storage.

[0080] Optionally, the operational constraints also include:

[0081] The dynamic characteristics constraints of the charge and discharge of the liquid hydrogen superconducting synergistic energy storage system are as follows:

[0082]

[0083] Among them, K SMES T is the proportionality constant of superconducting magnetic energy storage; SMES ΔP is the response time constant of superconducting magnetic energy storage. S_c K is the active power output control quantity for superconducting magnetic energy storage. EL T is the proportionality constant of the electrolytic cell; EL ΔP is the response time constant of the electrolyzer; EL_c K is the active power output control quantity of the electrolytic cell. FC T is the proportionality constant of the hydrogen fuel cell; FC ΔP is the response time constant of the hydrogen fuel cell; FC_c This refers to the active power output control quantity of hydrogen fuel cells.

[0084] Based on the active power output characteristics of superconducting magnetic energy storage and hydrogen energy storage, the output timing of liquid hydrogen superconducting co-existing energy storage is configured in stages, and a timing-based tiered response control strategy is formulated. Active power regulation commands are generated to control the coordination between superconducting magnetic energy storage and hydrogen energy storage in the liquid hydrogen superconducting co-existing energy storage system to stabilize the grid frequency.

[0085] Furthermore, starting from the coordination of multiple devices within the liquid hydrogen superconducting co-existing energy storage system, a time-series tiered response strategy is constructed: based on the instantaneous response of superconducting magnetic energy storage and the fact that hydrogen energy storage requires a certain start-up time T. HS The characteristics of this system include a tiered configuration of the output timing of liquid hydrogen superconducting co-existing energy storage. First, the active power output of the superconducting magnetic energy storage is used for frequency control, and then the active power output of the hydrogen energy storage is used for frequency control.

[0086] The timing-sequence response control strategy includes: firstly, using the active power output control amount of superconducting magnetic energy storage for frequency control; and then, after exceeding the set duration of superconducting magnetic energy storage output, using the active power output control amount of hydrogen energy storage for frequency control.

[0087] During the process of controlling the coordination between superconducting magnetic energy storage and hydrogen energy storage in the liquid hydrogen superconducting synergistic energy storage system using active power regulation commands, the active power output control quantity ΔP of the superconducting magnetic energy storage is... Sc :

[0088]

[0089] Among them, K S_up K represents the superconducting magnetic energy storage output loading rate. S_d For superconducting magnetic energy storage output load reduction rate; P S_max This represents the upper limit of superconducting magnetic energy storage output; T set The set duration of superconducting magnetic energy storage output is used to support the power system frequency before hydrogen energy storage is activated;

[0090] The active power output control quantity ΔP of the hydrogen energy storage H_c :

[0091]

[0092] Where H represents an electrolyzer (EL) or a hydrogen fuel cell (FC), and K... H_up For hydrogen energy storage output loading rate; K H_d For hydrogen storage output load reduction rate; P H_max This represents the upper limit of hydrogen storage power output.

[0093] The time-series tiered response control strategy satisfies the following constraints:

[0094] T set ≥T HS

[0095] ΔP H_c =0,T set ≥T HL

[0096] Among them, the duration of superconducting magnetic energy storage output T set Longer than the start-up time T of hydrogen energy storageHS If the superconducting magnetic energy storage output duration T is reached... set Before, hydrogen storage power output time T HS If the limit has been reached, the hydrogen storage power output will not be activated. At this time, the active power control value of the hydrogen storage will be set to 0.

[0097] Based on real-time measurement of the frequency change rate, an online control system for a liquid hydrogen superconducting co-existing energy storage system connected to the power grid provides active power support after a severe source-load imbalance frequency event occurs in the power system. In this embodiment, the liquid hydrogen superconducting co-existing energy storage system is adjusted to participate in grid frequency control according to the actual system conditions and in anticipation of potential frequency events.

[0098] To further illustrate the method for participating in grid frequency control using liquid hydrogen superconducting co-existing energy storage provided in this embodiment, Figure 2 The improved IEEE 9-node system is used as an example to verify the effectiveness of this method. This system includes two thermal power units, one wind farm, and one liquid hydrogen superconducting co-existing energy storage system, with a total active power load of 250MW. The liquid hydrogen superconducting co-existing energy storage system is connected to node 5, with a rated capacity of 7.5MW for superconducting magnetic energy storage, a rated capacity of 5MW for electro-hydrogen generation, and a rated capacity of 5MW for fuel cells. Grid frequency control is performed according to this method.

[0099] The simulation defines a load surge of 10% of the total load as a frequency event. The frequency performance of the systems with no energy storage, superconducting magnetic energy storage alone, hydrogen energy storage alone, and liquid hydrogen superconducting co-storage energy storage are analyzed. The simulation results are as follows: A comparison of the frequency control effects of different energy storage configurations participating in grid frequency control under the frequency event is shown below. Figure 3 The control effect of different energy storage configurations on the rate of change of grid system frequency under frequency events, for example... Figure 4 The output effect of a thermal power unit participating in grid frequency regulation under different energy storage configurations during frequency events, for example... Figure 5 Table 1 compares the maximum frequency deviation and quasi-steady-state frequency deviation of the power grid system participating in grid frequency control under different energy storage configurations during frequency events. Table 2 compares the maximum response output of generating units participating in grid frequency control under different energy storage configurations and the quasi-steady-state response output of a certain thermal power unit.

[0100] Table 1

[0101]

[0102] Table 2

[0103]

[0104] The simulation results show that utilizing liquid hydrogen superconducting co-existing energy storage in grid frequency control can fully leverage the combined power-type energy storage of the superconducting magnetic energy storage device and the energy-type energy storage of the hydrogen energy storage device, thus supporting the system frequency. The high response speed of the superconducting magnetic energy storage device ensures the reduction of the maximum frequency deviation; the output of the hydrogen energy storage device reduces the quasi-steady-state frequency deviation of the system. Overall, the participation of liquid hydrogen superconducting co-existing energy storage in frequency control also reduces the output of traditional thermal power frequency regulation, effectively improving the economic efficiency of system regulation after frequency events. Furthermore, the coordination of multiple devices within the liquid hydrogen superconducting co-existing energy storage avoids the drawbacks of single energy storage participating in frequency control. It avoids the problems of continued frequency drop and large quasi-steady-state frequency deviation when energy storage is withdrawn, as seen with single power-type energy storage, while also compensating for the insufficient response speed and excessive frequency change rate in the early stages of frequency events associated with single energy storage.

[0105] Example 2

[0106] A system for liquid hydrogen superconducting co-existing energy storage to participate in grid frequency control includes: a processor; and a memory storing a computer-executable program, which, when executed by the processor, causes the processor to perform the aforementioned method for liquid hydrogen superconducting co-existing energy storage to participate in grid frequency control. The related technical solutions are the same as in Embodiment 1 and will not be repeated here.

[0107] Example 3

[0108] A computer-readable storage medium stores a computer program thereon, which, when executed by a processor, implements the aforementioned method for participating in grid frequency control of liquid hydrogen superconducting co-existing energy storage. The related technical solutions are the same as in Embodiment 1 and will not be repeated here.

[0109] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for power grid frequency control based on liquid hydrogen superconducting eutectic energy storage system, characterized in that, Comprise: S100, when the power grid frequency event occurs, the maximum value of the system frequency rate of change is obtained according to the instantaneous frequency rate of change of the power grid, and the active power output control quantity of the liquid hydrogen superconducting co-melting energy storage system is determined according to the maximum value of the system frequency rate of change and the power response coefficient; S200, taking the charging and discharging dynamic characteristics of the liquid hydrogen superconducting co-melting energy storage system and the system energy storage capacity as operation constraints, controlling the output of the liquid hydrogen superconducting co-melting energy storage system according to the time sequence step response control strategy to meet the active power output control quantity; The time sequence step response control strategy comprises: firstly, using the active power output control quantity of the superconducting magnetic energy storage to control the frequency, and after exceeding the set superconducting magnetic energy storage output duration, gradually reducing the active power output of the superconducting magnetic energy storage with time, and at the same time, controlling the active power output of the hydrogen energy storage in the liquid hydrogen superconducting co-melting energy storage system to make up for the lack of active power output control quantity caused by the reduction of superconducting magnetic energy storage, so that the two cooperate to stabilize the power grid frequency; Wherein, the time sequence step response control strategy satisfies the following constraints: Wherein, the superconducting magnetic energy storage output duration Longer than hydrogen energy storage start-up time If the superconducting magnetic energy storage output duration The hydrogen energy storage output time Has reached the limit, the hydrogen energy storage output is not started; The hydrogen energy storage active power control quantity, The hydrogen energy storage output time limit.

2. The grid frequency control method of claim 1, wherein, When the power grid frequency event occurs, it also comprises: Obtaining the real-time frequency rate of change of the power grid, and comparing the positive and negative of the real-time frequency rate of change with the over-frequency response event action threshold and the under-frequency response event action threshold respectively to determine whether the power grid frequency event is an over-frequency event or an under-frequency event; If it exceeds the over-frequency response event action threshold / under-frequency response event action threshold, it is determined as an over-frequency event / under-frequency event, an event trigger signal is generated to trigger the corresponding over-frequency event / under-frequency event.

3. The grid frequency control method of claim 2, wherein, When the power grid frequency event occurs, the maximum value of the system frequency rate of change is obtained according to the instantaneous frequency rate of change of the power grid, comprising: Real-time frequency measurement is performed at a measurement point of a power grid, and a frequency change rate is obtained by derivation of the real-time frequency measurement value ; and the power grid frequency event is determined to be an over-frequency event or an under-frequency event by comparing the real-time frequency measurement value with the over-frequency response event action threshold and the under-frequency response event action threshold, respectively; wherein the logic relationship for generating the event trigger signal is as follows: wherein, is an under-frequency response event trigger signal; is an under-frequency response event action threshold; is an over-frequency response event trigger signal; is an over-frequency response event action threshold; For under-frequency response event, the minimum value of the frequency rate of change in the historical event is obtained, compared with the current frequency rate of change, and the minimum value is calculated as the active power output control quantity: wherein, is the active power control quantity for the under-frequency response event; is the power response coefficient; is the minimum rate of change of frequency in the historical under-frequency response event; For over-frequency response event, the maximum value of the frequency rate of change in the historical event is obtained, compared with the current frequency rate of change, and the maximum value is calculated as the active power output control quantity: wherein, is the active power control quantity for the over-frequency response event; is the maximum value of the rate of change of frequency in the historical over-frequency response events.

4. The grid frequency control method of claim 1, wherein, The operation constraints include superconducting magnetic energy storage constraints and hydrogen energy storage liquid level constraints; The superconducting magnetic energy storage constraint is: wherein, is a lower limit of state of charge variation of the superconducting magnetic energy storage; is an upper limit of state of charge variation of the superconducting magnetic energy storage; is an active power response quantity of the superconducting magnetic energy storage; is a capacity of the superconducting magnetic energy storage; is an output time limit of the superconducting magnetic energy storage; The hydrogen energy storage liquid level constraint is: wherein, is a hydrogen storage energy state of charge change lower limit; is a hydrogen storage energy state of charge change upper limit; is a hydrogen storage energy active power response quantity, which is a function of an electrolyzer active power response quantity and a hydrogen fuel cell active power response quantity ; is a hydrogen storage energy capacity; is a liquid hydrogen evaporation coefficient caused by superconducting magnetic storage energy heat; is a hydrogen storage energy output time limit.

5. The grid frequency control method of claim 4, wherein, The operation constraints also include: The dynamic characteristics of the liquid hydrogen superconducting co-melting energy storage system charging and discharging: wherein, is a proportional constant for the superconducting magnetic energy storage; is a response time constant for the superconducting magnetic energy storage; is an active power output control variable for the superconducting magnetic energy storage, is a proportional constant for the electrolyzer; is a response time constant for the electrolyzer; is an active power output control variable for the electrolyzer; is a proportional constant for the hydrogen fuel cell; is a response time constant for the hydrogen fuel cell; is an active power output control variable for the hydrogen fuel cell.

6. The power grid frequency control method of claim 1, characterized in that, Active power output control variable of superconducting magnetic energy storage : wherein, is the superconducting magnetic energy storage output load rate; is the superconducting magnetic energy storage output unload rate; is the superconducting magnetic energy storage output upper limit; is the set superconducting magnetic energy storage output duration, supporting power system frequency before hydrogen energy storage action. The active power output control amount of the hydrogen storage energy : wherein, H represents an electrolytic tank ( EL ) or a hydrogen fuel cell ( FC ), is a hydrogen storage energy output loading rate; is a hydrogen storage energy output unloading rate; is a hydrogen storage energy output upper limit; 7. A power grid frequency control system based on liquid hydrogen superconducting eutectic energy storage system, characterized in that, Comprise: Memory and processor, the memory stores computer programs, the processor executes the computer programs to execute the method provided in any one of claims 1-6.

8. A computer-readable storage medium having stored thereon a computer program, characterized in that, The program is executed by the processor to realize the liquid hydrogen superconducting co-melting energy storage participating in the power grid frequency control method in any one of claims 1-6.

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