Flywheel energy storage self-restoration control method and system considering unit AGC frequency modulation state

Abstract

The application discloses a flywheel energy storage self-recovery control method considering the frequency modulation state of a unit AGC, and comprises the following steps: S1, when detecting that there is any step change in the AGC instruction, acquiring the state information of the flywheel energy storage, and calculating the corresponding state of charge value; S2, when the state of charge value meets the constraint condition, setting two threshold points to divide the state of charge into multiple regions; S3, based on the rated power of the flywheel energy storage and the power deviation of the unit, calculating the required output power of the flywheel energy storage and outputting; S4, adding a virtual AGC instruction control logic and generating a virtual load instruction increment ΔAGC of the unit, adjusting the size of the load instruction increment ΔAGC, and controlling the current value of the state of charge value in the optimal charge interval. According to the state information of the flywheel energy storage, the application dynamically adjusts the virtual AGC instruction of the unit, and then adjusts the output power of the unit, and simultaneously enables the flywheel energy storage to operate in the optimal charge interval.

Description

Technical Field

[0001] This invention relates to the fields of flywheel energy storage and thermal power unit control technology, specifically to a flywheel energy storage self-recovery control method and system that takes into account the frequency regulation state of the unit's AGC. Background Technology

[0002] The new energy industry is developing rapidly, the proportion of clean energy consumption is increasing significantly, and the green and low-carbon transformation is accelerating. It is projected that by 2030, the proportion of non-fossil energy consumption will reach approximately 25%, with clean energy becoming the main driver of incremental energy consumption. As the installed capacity of new energy continues to expand, the integration of new energy sources has become a key issue. At the same time, due to the volatility and intermittency of new energy grid connection, exhibiting a "duck-shaped curve" load characteristic, coal-fired power units face increasing pressure in participating in deep peak shaving and frequency regulation to achieve a low-carbon energy transformation.

[0003] With the continuous optimization of new energy deployment and the sustained decline in energy storage costs, guided by national policies, the business models of energy storage in the power ancillary services market, peak-valley price arbitrage, and addressing wind and solar curtailment are gradually strengthening. Flywheel energy storage boasts advantages such as frequent charge-discharge capability and long cycle life, exceeding 5 million cycles. A flywheel + thermal power unit combined frequency regulation system can participate in AGC frequency regulation and obtain ancillary service compensation revenue.

[0004] On the other hand, due to the high energy cost of flywheel energy storage, the power generation side often considers the cost recovery period when configuring flywheel energy storage, and the power capacity of flywheel energy storage is not sufficient to meet the all-weather frequency regulation conditions; thus reducing the frequency regulation performance of the thermal-storage joint system, reducing the participation of flywheel energy storage, and reducing the revenue of the joint system.

[0005] While some self-recovering control strategies force SOC self-recovery when it exceeds the normal charging and discharging range (SOC stands for State of Charge), they do not consider whether the combined system is participating in AGC frequency regulation. This leads to lower frequency regulation performance of the combined energy storage system, and even sudden drops in grid frequency. AGC stands for Automatic Generation Control, a technology in power systems used to maintain grid frequency, control power exchange between interconnected areas, and adjust generator output in response to load changes.

[0006] Currently, existing technologies for flywheel energy storage coupled with thermal power units still have the following shortcomings regarding the self-recovery of State of Charge (SOC): 1) The importance of the optimal state of charge of flywheel energy storage in the frequency regulation process was not fully considered; 2) The lack of attention to the SOC recovery strategy caused the flywheel energy storage to operate in a boundary state for a long time; 3) The output characteristics of the unit are not fully utilized during the SOC transformation process. Summary of the Invention

[0007] In view of the above three problems, the object of the present invention is to propose a flywheel energy storage self-restoration control method and system considering the AGC frequency modulation state of the unit, which can dynamically adjust the virtual AGC command of the unit according to the state information of the flywheel energy storage, and then adjust the output power of the unit. At the same time, the operation of the flywheel energy storage is in the optimal state of charge, realizing the combined frequency modulation of thermal power and energy storage, improving the adjustable energy of the flywheel energy storage, giving full play to the output characteristics of the unit, meeting the all-weather AGC frequency modulation service, realizing the optimal configuration and control of energy storage resources and the maximum utilization, and improving the project rate of return.

[0008] It is achieved through the following technical solutions: First, a flywheel energy storage self-restoration control method considering the AGC frequency modulation state of the unit is proposed, including the following steps: S1. Obtain the AGC command of the power grid. When any step change is detected in the AGC command, obtain the state information of the flywheel energy storage and calculate the state of charge value SOC of the flywheel energy storage at the corresponding step change. S2. Determine whether the state of charge value SOC in step S1 satisfies the constraint condition: 0.2 ≤ SOC ≤ 0.95; if not, prohibit charging and discharging of the flywheel energy storage; if satisfied, set threshold point A and threshold point B to divide the state of charge of the flywheel energy storage into multiple regions, and then enter step S3; where 0.2 < A < B < 0.95, (A, B) is the optimal state of charge interval. S3. Obtain the actual power P g (t) of the unit, and calculate the power deviation P e (t) = P AGC (t) - P g (t), where P AGC [[ID=2VI]] (t) is the current specified power value of the power grid, and P g (t) is the rated power of the unit. Based on the rated power of the flywheel energy storage and the power deviation of the unit, according to formula (1): Calculate the output power P f (t) required by the flywheel energy storage, where P fe is the rated power of the flywheel energy storage; Output the flywheel energy storage according to the calculated output power P f (t). S4. Add virtual AGC command control logic to the unit and generate an incremental virtual load command ΔAGC of the unit, and obtain the current value of the state of charge value SOC of the flywheel energy storage after outputting according to the output power P f (t) in step S3. Adjust the load command increment ΔAGC to control the current value of the state of charge (SOC) within the optimal charge range; when the current value of SOC is A or B and ΔAGC = 0, stop the unit regulation.

[0009] By treating the step change of the AGC command as a frequency regulation command, a rapid response can be achieved. Then, the output power of the flywheel energy storage can be accurately obtained based on the unit's output power. The virtual AGC command control logic is then used to dynamically adjust the load command increment, so that the flywheel energy storage can operate stably in the optimal charge range.

[0010] Preferably, the state information obtained in step S1 includes the rated angular velocity of the flywheel energy storage. angular velocity Rated power E e And the current charge E, the state of charge (SOC) = Where J is the moment of inertia. By combining the rated information with the current actual information, the current state of charge can be effectively calculated, facilitating adjustments based on the state of charge.

[0011] Preferably, in step S2, A=0.4, B=0.8; (0.2,0.4) and (0.8,0.95) are both secondary charge ranges. Setting A=0.4 and B=0.8 ensures that the flywheel energy storage has sufficient buffer range to cope with sudden changes in energy demand or supply, without having to frequently reach the limit value, thereby improving the stability and efficiency of the system.

[0012] Preferably, the unit is equipped with a dead-zone power value, the magnitude of which is equal to the unit's rated power P. g (t) is 1%. The dead zone power value can optimize the unit's response characteristics. The dead zone power value is only 1% of the unit's rated power, which is small enough to improve the response speed to load changes.

[0013] Preferably, when generating the unit's load command increment ΔAGC in step S4, ΔAGC does not exceed the dead zone power value. Limiting ΔAGC to not exceed the dead zone power value can maintain the stable operation of the unit.

[0014] Preferably, after obtaining the current value of the state of charge (SOC) in step S4, a charging power rate parameter k is set. d and a discharge power ratio parameter k c According to k d and k c Calculate the virtual load command increment ΔAGC for the unit. Charging power rate parameter k. d and a discharge power ratio parameter k cIt is an important parameter related to the state of charge, and can effectively calculate the corresponding load command increment ΔAGC.

[0015] Preferably, , When ΔP>0, ΔAGC= When Δp < 0, ΔAGC = Where ΔP is the updated value of flywheel energy storage, ΔP = P ACG (t1)-P ACG (t0), P ACG (t1) represents the ACG instruction value at time t1, P ACG (t0) represents the ACG instruction value one moment before time t1; the virtual AGC instruction value of the unit is denoted as P. * AGC (t), ΔAGC=P * AGC (t)-P AGC (t), by modifying P * AGC (t) Control ΔAGC until the current value of the state of charge (SOC) is A or B and ΔAGC = 0, then stop the unit regulation. By modifying the virtual AGC command value of the unit, the combined frequency regulation of thermal and energy storage power can be completed, which not only keeps the flywheel energy storage in the optimal charge range, but also makes full use of the unit's output characteristics, and the regulation speed is fast.

[0016] Secondly, a system is proposed that operates using a flywheel energy storage self-recovery control method that considers the frequency regulation state of the generator AGC, as described in any of the preceding items.

[0017] Furthermore, an electronic device is proposed for supporting the operation of the system as described above.

[0018] In addition, a storage medium is proposed for supporting the operation of the aforementioned electronic devices.

[0019] The beneficial effects of this invention compared to the prior art are: The technical solution of this invention can dynamically adjust the virtual AGC commands of the generator unit based on the state information of the flywheel energy storage, thereby adjusting the output power of the generator unit. At the same time, it can make the flywheel energy storage operate in the optimal charge range, realize the joint frequency regulation of thermal and energy storage power, improve the adjustable energy of flywheel energy storage, give full play to the output characteristics of the generator unit, meet the all-weather AGC frequency regulation service, realize the optimal configuration, control and maximum utilization of energy storage resources, and improve the project yield. Attached Figure Description

[0020] Figure 1 A flowchart of a flywheel energy storage self-recovery control method considering the frequency regulation state of the generator set's AGC; Figure 2 It is a schematic diagram of combined fire and energy storage frequency regulation after a step change in the AGC command; Figure 3 It is a schematic diagram of the output of a unit when increasing load according to a virtual AGC command; Figure 4 It is a schematic diagram of the output of a unit when decreasing load according to a virtual AGC command. Specific implementation manners

[0021] Next, the technical solutions in the embodiments of the present invention will be described in detail with reference to the accompanying drawings in the embodiments of the present invention.

[0022] As Figure 1 shown, it is a flowchart of a flywheel energy storage self - recovery control method considering the AGC frequency regulation state of a unit. According to the state information of the flywheel energy storage, the output power of the unit, that is, the output power of the unit, is dynamically adjusted, which can effectively control the flywheel energy storage to operate in the optimal state of charge. The full name of the flywheel energy storage is the flywheel energy storage system. The method specifically includes the following steps: S1. Obtain the AGC command of the power grid. When any step change is detected in the AGC command, obtain the state information of the flywheel energy storage, and calculate the state of charge value SOC of the flywheel energy storage at the corresponding step change. Denote the required command update value of the flywheel energy storage at the step change as ΔP, ΔP = P ACG (t1) - P ACG (t0), P ACG (t1) is the AGC command value at time t1, P ACG (t0) is the AGC command value at time t0, which is also the AGC command value at the moment before t1. ΔP≠0 means that the operating condition of the flywheel energy storage needs to be changed.

[0023] In this embodiment, the state information obtained in step S1 includes the rated angular velocity of the flywheel energy storage , angular velocity , rated electric quantity E e and the current electric quantity E. The state of charge value SOC = ,, where J is the moment of inertia.

[0024] S2. Judge whether the state of charge value SOC in step S1 satisfies the constraint condition: 0.2≤SOC≤0.95; if not, it means that the flywheel energy storage is operating in a relatively extreme situation at this time, and it is difficult to adjust, so it is not suitable for dynamic change. Then, the flywheel energy storage is prohibited from charging and discharging; if it is satisfied, set the threshold point A and threshold point B to divide the state of charge of the flywheel energy storage into multiple regions, and then enter step S3; where 0.2 < A < B < 0.95, (A, B) is the optimal state of charge interval, which is also the optimal operating interval of the flywheel energy storage.

[0025] Specifically, A=0.4 and B=0.8 can be set. In this case, (0.4, 0.8) is the optimal charging range, with the largest charge / discharge margin and strong ability to handle continuous charging and discharging. (0.2, 0.4) and (0.8, 0.95) are both secondary charging ranges, possessing a certain degree of unidirectional charge / discharge capability. Setting A=0.4 and B=0.8 provides the flywheel energy storage with sufficient buffer range to cope with sudden changes in energy demand or supply, without having to frequently reach the limit value, thereby improving the stability and efficiency of the system.

[0026] S3, Obtain the actual power P of the unit g (t), the unit is the thermal power unit, and the power deviation P is calculated. e (t) = P AGC (t)-P g (t), where P AGC (t) represents the current specified power value of the power grid, P g (t) represents the rated power of the unit; based on the rated power of the flywheel energy storage and the power deviation of the unit, according to formula (1): Calculate the output power P required for flywheel energy storage. f (t), where P fe The rated power of the flywheel energy storage; the flywheel energy storage is calculated according to the output power P. f (t) is used for output.

[0027] like Figure 2 The diagram shows a combined thermal power generation and energy storage frequency regulation after an AGC command undergoes a step change. Combined thermal power generation and energy storage refers to the coordinated operation of the thermal power unit and the flywheel energy storage. At time t1, the AGC command undergoes a step change, and the unit operates according to the AGC command. The flywheel energy storage assists the thermal power unit in its frequency regulation response curve, discharging stored energy. Figure 2 In the diagram, the red line represents the AGC command line, the black line represents the actual power output curve of the thermal power unit (also known as the actual power output curve), and the blue line represents the flywheel energy storage power curve, which includes discharge or charging. At time t3, the thermal power unit tracks the AGC command, meaning the thermal power unit has completed the execution of the command, and the flywheel energy storage stops adjusting.

[0028] S4. Add virtual AGC command control logic to the unit and generate virtual load command increment ΔAGC for the unit, and obtain the flywheel energy storage output power P according to step S3. f (t) The current value of the state of charge (SOC) after output; adjust the magnitude of the load command increment ΔAGC to control the current value of the SOC within the optimal charge range; when the current value of the SOC is A or B and ΔAGC = 0, stop the unit regulation.

[0029] In this embodiment, the unit is equipped with a dead-zone power value, the magnitude of which is equal to the unit's rated power P. g (t) 1%; When generating the unit's load command increment ΔAGC in step S4, ΔAGC does not exceed the dead zone power value. The dead zone power value can optimize the unit's response characteristics. The dead zone power value accounts for only 1% of the unit's rated power, which is small enough to improve the response speed to load changes.

[0030] In this embodiment, after obtaining the current value of the state of charge (SOC) in step S4, a charging power rate parameter k is set. d and a discharge power ratio parameter k c ;in, , According to k d and k c Calculate the virtual load command increment ΔAGC for the unit. When ΔP > 0, ΔAGC = When Δp < 0, ΔAGC = The virtual AGC command value of the unit is recorded as P. * AGC (t), ΔAGC=P * AGC (t)-P AGC (t), by modifying P * AGC (t) Control ΔAGC until the current value of the state of charge (SOC) is A or B and ΔAGC = 0, then stop the unit regulation. By modifying the virtual AGC command value of the unit, the combined frequency regulation of thermal and energy storage power can be completed, which not only keeps the flywheel energy storage in the optimal charge range, but also makes full use of the unit's output characteristics, and the regulation speed is fast.

[0031] like Figure 3 The diagram shows the output of a unit when increasing load according to a virtual AGC command. The above method is used to verify the load increase. At time t1, the load change occurs in the AGC command, and the unit starts to run according to the virtual AGC command. The frequency response curve of the flywheel energy storage auxiliary thermal power unit continues to output according to formula (1). The red line is the AGC command line, the red dotted line is the virtual AGC command, the black line is the actual power curve of the thermal power unit, and the blue line is the discharge power curve of the flywheel energy storage. At time t2, the thermal power unit tracks the AGC command. At time t3, the thermal power unit tracks the virtual AGC command until the state of charge (SOC) value of the flywheel energy storage is 0.4, the virtual AGC increment is 0, and the unit adjustment is completed.

[0032] like Figure 4The diagram shows the output of a unit when reducing load according to a virtual AGC command. The load reduction is verified again using the above method. At time t1, the load reduction changes due to the AGC command. The unit starts running according to the virtual AGC command. The frequency response curve of the flywheel energy storage-assisted thermal power unit continues to be output according to formula (1). The red line is the AGC command line, the red dashed line is the virtual AGC command, the black line is the actual power curve of the thermal power unit, and the purple line is the charging power curve of the flywheel energy storage. At time t2, the thermal power unit tracks the AGC command. At time t3, the thermal power unit tracks the virtual AGC command. The unit adjusts until the state of charge (SOC) value of the flywheel energy storage is 0.8 and the virtual AGC increment is 0.

[0033] Secondly, a system is proposed that operates using a flywheel energy storage self-recovery control method that considers the frequency regulation state of the generator set's AGC.

[0034] Furthermore, an electronic device is proposed for supporting the operation of the system as described above.

[0035] In addition, a storage medium is proposed that is readable and used to support the operation of the aforementioned electronic devices.

[0036] In summary, this invention can dynamically adjust the virtual AGC commands of the generator unit based on the state information of the flywheel energy storage, thereby adjusting the unit's output power. Simultaneously, it ensures that the flywheel energy storage operates within its optimal charge range, achieving joint frequency regulation of thermal and energy storage power, enhancing the adjustable energy of the flywheel energy storage, fully utilizing the unit's output characteristics, meeting all-weather AGC frequency regulation service requirements, realizing optimal allocation, control, and maximum utilization of energy storage resources, and improving project profitability. This invention represents a significant advancement.

[0037] The above embodiments are merely illustrative of the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solutions based on the technical concept proposed in this invention shall fall within the scope of protection of this invention.

Claims

1. A flywheel energy storage self-recovery control method considering the frequency regulation state of the generator set's AGC, characterized in that, It includes the following steps: S1. Obtain the AGC command of the power grid. When any step change is detected in the AGC command, obtain the state information of the flywheel energy storage, and calculate the state of charge value SOC of the flywheel energy storage at the corresponding step change; S2. Determine whether the state of charge value SOC in step S1 meets the constraint conditions: 0.2 ≤ SOC ≤ 0.95; if not, prohibit charging and discharging of the flywheel energy storage; if so, set threshold point A and threshold point B to divide the state of charge of the flywheel energy storage into multiple regions, and then enter step S3; where, 0.2 < A < B < 0.95, (A, B) is the optimal state of charge interval; S3, Obtain the rated power P of the unit g (t), calculate the power deviation P e (t) = P AGC (t)-P g (t), where P AGC (t) represents the current specified power value of the power grid, P g (t) represents the rated power of the unit; Based on the rated power of the flywheel energy storage and the power deviation of the unit, according to formula (1): Calculate the output power P required for flywheel energy storage. f (t), where P fe Rated power for flywheel energy storage; The flywheel energy storage is calculated based on the output power P. f (t) is used for output; S4. Add virtual AGC command control logic to the unit and generate virtual load command increment ΔAGC for the unit, and obtain the flywheel energy storage output power P according to step S3. f (t) The current value of the state of charge (SOC) after output, and then set a charging power rate parameter k. d and a discharge power ratio parameter k c According to k d and k c Calculate the virtual load command increment ΔAGC for the unit; the unit is set with a dead zone power value, the size of which is equal to the unit's rated power P. g (t) 1%; When generating the load command increment ΔAGC of the unit, ΔAGC shall not exceed the dead zone power value; Adjust the magnitude of the load command increment ΔAGC to control the current value of the state of charge value SOC within the optimal state of charge interval; when the current value of the state of charge value SOC is A or B and ΔAGC = 0, stop the unit regulation; in, , When ΔP>0, ΔAGC= When ΔP < 0, ΔAGC = Where ΔP is the updated value of flywheel energy storage, ΔP = P AGC (t1)-P AGC (t0), P AGC (t1) represents the AGC command value at time t1, P AGC (t0) represents the AGC command value one moment before time t1; the virtual AGC command value of the unit is denoted as P. * AGC (t), ΔAGC=P * AGC (t)-P AGC (t), by modifying P * AGC (t) Control ΔAGC until the current value of the state of charge (SOC) is A or B and ΔAGC = 0, then stop the unit regulation.

2. The flywheel energy storage self-recovery control method considering the frequency regulation state of the generator AGC as described in claim 1, characterized in that, The state information obtained in step S1 includes the rated angular velocity of the flywheel energy storage. angular velocity Rated power E e And the current charge E, the state of charge (SOC) = , where J is the moment of inertia.

3. The flywheel energy storage self-recovery control method considering the frequency regulation state of the generator set's AGC, as described in claim 1, is characterized in that... In step S2, A = 0.4, B = 0.8; (0.2, 0.4) and (0.8, 0.95) are both secondary state of charge intervals.

4. A system, characterized in that, The system operates by using a flywheel energy storage self-recovery control method as described in any one of claims 1 to 3 that takes into account the AGC frequency modulation state of the unit.

5. An electronic device, characterized in that, The electronic device is used to support the operation of the system as described in claim 4.

6. A storage medium, characterized in that, The storage medium is used to support the operation of the electronic device as described in claim 5.

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