Energy storage system frequency stability control method and device, electronic equipment and medium

Abstract

The invention relates to a frequency stability control method and device of an energy storage system, electronic equipment and a medium, and belongs to the technical field of energy storage. Power disturbance occurs in the steady-state operation process of the system, the disturbance is not a three-phase short circuit, primary frequency modulation is used for frequency modulation of the system, the system can be effectively and stably controlled, and the stability of the system is improved. When the frequency is not recovered to an allowable range after the primary frequency modulation, performing accelerated frequency modulation, and after the accelerated frequency modulation, if the frequency is recovered to a rated value, ending the frequency modulation; if the frequency is not recovered to the rated value, performing secondary frequency modulation, and ending frequency modulation when the frequency is recovered to the rated value; wherein the accelerated frequency modulation is used for supplementing the primary frequency modulation, so that the frequency vacancy required to be supplemented by the secondary frequency modulation is reduced, the speed of the secondary frequency modulation is higher, the impact of the secondary frequency modulation on the system is also reduced, and the stability of the system is effectively improved.

Description

Technical Field

[0001] The present invention relates to the field of energy storage technology, and in particular to a frequency stabilization control method, device, electronic equipment and medium for an energy storage system. Background Art

[0002] With the rapid development of new power system construction, the power system grid structure is moving towards power electronics. Some regional power grids can already be independently powered by energy storage as the main power source. One of the main tasks of power system operation is to control the grid frequency. The existing technology often uses a droop control strategy to control the system, but when a three-phase short circuit fault occurs, the droop control strategy is not enough to meet the system frequency stability requirements and needs to be switched to other control modes. When a system fault occurs, primary and secondary frequency modulation is generally performed based on the current control mode.

[0003] Primary frequency regulation refers to the service provided by conventional units through the automatic response of the speed regulation system, and grid-connected entities such as new energy and energy storage through rapid frequency response to reduce frequency deviation when the power system frequency deviates from the target frequency. Secondary frequency regulation refers to the service provided by the grid-connected entity through automatic power control technology, including automatic generation control (AGC) and automatic power control (APC), to track the instructions issued by the power dispatching agency and adjust the power generation and consumption in real time at a certain adjustment rate to meet the power system frequency and interconnection line power control requirements. For energy storage, it is mainly AGC service. Only after secondary frequency regulation can the grid frequency be accurately maintained at a constant value. However, since secondary frequency regulation faces frequency deviation caused by large load changes and long change cycles, it will cause secondary frequency regulation to have large frequency modulation amplitude and slow frequency modulation speed, thus affecting the stability of the system. Summary of the invention

[0004] The purpose of the present invention is to provide a method, device, electronic equipment and medium for frequency stability control of an energy storage system, so as to solve the problem that the secondary frequency modulation has a large impact and the frequency modulation is slow, which affects the stability of the system.

[0005] In order to solve the above technical problems, the present invention provides a frequency stabilization control method for an energy storage system, comprising:

[0006] If a power disturbance occurs during the steady-state operation of the system, and the cause of the disturbance is not a three-phase short circuit, the energy storage system will perform a frequency modulation within the frequency modulation setting time based on the droop principle;

[0007] If the frequency is not restored to the allowable range after the first frequency modulation, the acceleration frequency modulation is performed within the acceleration frequency modulation setting time. The process of the acceleration frequency modulation is as follows: the product of the frequency deviation after the first frequency modulation and the frequency modulation coefficient of the energy storage system is calculated to obtain the acceleration frequency modulation power command, and the acceleration frequency modulation power command is superimposed on the power command after the first frequency modulation;

[0008] After the accelerated frequency modulation, if the frequency recovers to the rated value, the frequency modulation ends; if the frequency does not recover to the rated value, a secondary frequency modulation is performed, and the frequency modulation ends when the frequency recovers to the rated value.

[0009] The beneficial effects of the above technical solution are: when power disturbance occurs during the steady-state operation of the system, and the cause of the disturbance is not a three-phase short circuit, the system can be effectively stabilized by using primary frequency modulation to modulate the system. When the frequency has not recovered to the allowable range after the primary frequency modulation, accelerated frequency modulation is performed. Accelerated frequency modulation is a supplement to the primary frequency modulation, which reduces the frequency shortage that needs to be supplemented by the secondary frequency modulation, making the secondary frequency modulation faster and reducing the impact of the secondary frequency modulation on the system. If the frequency has not recovered to the rated value after accelerated frequency modulation, secondary frequency modulation is performed to restore the system frequency to stability through secondary frequency modulation.

[0010] Furthermore, if the frequency recovers to within the allowable range after one frequency modulation, the frequency modulation is terminated.

[0011] The beneficial effect of the above technical solution is that when the frequency returns to stability after one frequency modulation, there is no need to perform subsequent steps, and the frequency modulation is directly ended to save adjustment time.

[0012] Furthermore, if the disturbance is caused by a three-phase short circuit, the energy storage system switches to a constant frequency control mode to limit the output voltage and current to maintain the frequency near the rated value.

[0013] The beneficial effect of the above technical solution is: if the disturbance is caused by a three-phase short circuit, the system bus voltage will drop sharply and the system power will also increase suddenly, making it difficult to adjust the frequency based on the droop principle. Therefore, constant frequency control is selected to adjust the system to maintain system stability.

[0014] Furthermore, after the energy storage system switches to the constant frequency control mode, if the system short circuit fault is removed, the system switches back to the normal working mode; if the system short circuit fault is not removed, the system maintains the constant frequency mode unchanged until the fault is removed.

[0015] The beneficial effects of the above technical solution are: when the system fault is eliminated, the system does not need to continue in the constant frequency control mode, and switching the system back to the normal working mode is beneficial to the stability of the system; if the system short-circuit fault has not been eliminated, the system still has unstable factors. At this time, for the stability of the system, the constant frequency mode should be maintained unchanged to help the relay protection device and new energy effectively eliminate the fault and provide reactive voltage support.

[0016] In order to solve the above technical problems, the present invention also provides a frequency stabilization control device for an energy storage system, comprising:

[0017] The primary frequency modulation module is used to perform a frequency modulation within the primary frequency modulation setting time based on the droop principle if a power disturbance occurs during the steady-state operation of the system and the disturbance is not caused by a three-phase short circuit;

[0018] The acceleration frequency modulation module is used to perform acceleration frequency modulation within the acceleration frequency modulation setting time if the frequency has not been restored to the allowable range after the first frequency modulation. The process of acceleration frequency modulation is as follows: the product of the frequency deviation after the first frequency modulation and the frequency modulation coefficient of the energy storage system is calculated to obtain the acceleration frequency modulation power instruction, and the acceleration frequency modulation power instruction is superimposed on the power instruction after the first frequency modulation;

[0019] The secondary frequency modulation module is used to terminate the frequency modulation if the frequency recovers to the rated value after the acceleration frequency modulation; if the frequency does not recover to the rated value, secondary frequency modulation is performed, and the frequency modulation ends when the frequency recovers to the rated value.

[0020] The beneficial effects of the above technical solution are: the frequency stability control device of the energy storage system controls the system, and power disturbance occurs during the steady-state operation of the system, and the cause of the disturbance is not a three-phase short circuit. The system is frequency-modulated using primary frequency modulation, which can effectively stabilize the system. When the frequency has not recovered to the allowable range after the primary frequency modulation, accelerated frequency modulation is performed. Accelerated frequency modulation is a supplement to the primary frequency modulation, which reduces the frequency shortage that needs to be supplemented by the secondary frequency modulation, making the secondary frequency modulation faster, and also reducing the impact of the secondary frequency modulation on the system. If the frequency has not recovered to the rated value after the accelerated frequency modulation, secondary frequency modulation is performed, and the system frequency is restored to stability through secondary frequency modulation.

[0021] Furthermore, if the frequency recovers to within the allowable range after one frequency modulation, the frequency modulation is terminated.

[0022] The beneficial effect of the above technical solution is that when the frequency in the energy storage system frequency stability control device returns to stability after one frequency modulation, there is no need to perform subsequent steps, and the frequency modulation is directly ended to save adjustment time.

[0023] Furthermore, if the disturbance is caused by a three-phase short circuit, the energy storage system switches to a constant frequency control mode to limit the output voltage and current to maintain the frequency near the rated value.

[0024] The beneficial effect of the above technical solution is: in the frequency stability control device of the energy storage system, if the disturbance cause is a three-phase short circuit, the system bus voltage will drop sharply and the system power will also increase suddenly, making it difficult to adjust the frequency based on the droop principle. Therefore, constant frequency control is selected to adjust the system to maintain system stability.

[0025] Furthermore, after the energy storage system switches to the constant frequency control mode, if the system short circuit fault is removed, the system switches back to the normal working mode; if the system short circuit fault is not removed, the system maintains the constant frequency mode unchanged until the fault is removed.

[0026] The beneficial effects of the above technical solution are: in the frequency stability control device of the energy storage system, when the system fault is eliminated, the system does not need to continue the constant frequency control mode, and switching the system back to the normal working mode is beneficial to the stability of the system; if the system short-circuit fault is not eliminated, the system still has unstable factors. At this time, for the stability of the system, it should also be maintained in the constant frequency mode unchanged, helping the relay protection device and new energy to effectively eliminate the fault and provide reactive voltage support.

[0027] To solve the above technical problems, the present invention also provides an electronic device, including a memory and a processor, and a computer program stored in the memory and running on the processor, wherein the processor is used to execute the computer program instructions stored in the memory to implement a frequency stabilization control method for an energy storage system.

[0028] The beneficial effect of the above technical solution is that the electronic device executes the energy storage system frequency stabilization control method stored in the memory through the processor to control the system so that the system maintains steady-state operation under power disturbance.

[0029] In order to solve the above technical problems, the present invention also provides a storage medium, on which a computer program is stored, characterized in that the computer program is used to implement a frequency stabilization control method for an energy storage system when executed by a processor.

[0030] The beneficial effect of the above technical solution is: the storage medium is used for the frequency stability control method of the energy storage system, which is executed by the processor to achieve control of the system so that the system maintains steady-state operation under power disturbance. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a schematic diagram of an application scenario of a frequency stabilization control method for an energy storage system according to an embodiment of the method of the present invention;

[0032] Figure 2 It is a flow chart of a frequency stabilization control method for an energy storage system according to an embodiment of the present invention. DETAILED DESCRIPTION

[0033] A frequency stabilization control method for an energy storage system includes the following steps: first, if a power disturbance occurs during the steady-state operation of the system, and the cause of the disturbance is not a three-phase short circuit, the energy storage system performs a frequency modulation within the primary frequency modulation setting time based on the droop principle; then, if the frequency does not recover to the allowable range after the primary frequency modulation, an accelerated frequency modulation is performed within the accelerated frequency modulation setting time, and after the accelerated frequency modulation, if the frequency recovers to the rated value, the frequency modulation ends; if the frequency does not recover to the rated value, a secondary frequency modulation is performed, and finally the frequency recovers to the rated value and the frequency modulation ends; the accelerated frequency modulation supplements the primary frequency modulation between the primary and secondary frequency modulations, reducing the frequency shortage that needs to be supplemented by the secondary frequency modulation, thereby reducing the impact of the secondary frequency modulation on the system and the time required for the secondary frequency modulation. Figure 1 The figure shows an example of the application scenario of this patent. The system is independently powered by energy storage as the main power source. The entire system is equipped with a relay protection device. At the same time, the new energy generator set can be connected to the grid to provide clean energy for the system.

[0034] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is further described in detail below with reference to the accompanying drawings and embodiments.

[0035] An energy storage system frequency stabilization control method embodiment:

[0036] A frequency stabilization control method for an energy storage system, specifically Figure 2 As shown:

[0037] 1) If a power disturbance occurs during the steady-state operation of the system, first determine whether the disturbance is caused by a three-phase short circuit. If not, the energy storage system performs a frequency modulation based on the droop principle, that is, the active power of the energy storage and the frequency of the output voltage are in an inverse linear relationship. When the active power increases, the frequency decreases. Otherwise, the specific calculation formula for adjusting the power is:

[0038] ΔP=K*Δf

[0039] In the formula, ΔP is the power regulation command increase value, K is the frequency regulation coefficient of the energy storage system, and Δf is the frequency deviation.

[0040] 2) If the frequency is restored to within the allowable range after one frequency modulation, the frequency modulation is terminated; if the frequency is not restored to within the allowable range, the frequency modulation is accelerated;

[0041] 3) The process of accelerating frequency modulation is as follows: the product of the frequency deviation after the primary frequency modulation and the frequency modulation coefficient of the energy storage system is calculated to obtain the accelerating frequency modulation power instruction, and the accelerating frequency modulation power instruction is superimposed on the power instruction after the primary frequency modulation and then executed by the energy storage converter. The specific calculation formula of the regulating power of accelerating frequency modulation is:

[0042] ΔP1=K*Δf1

[0043] Where ΔP1 is the increase in the power command for acceleration frequency regulation, K is the frequency regulation coefficient of the energy storage system, and Δf1 is the frequency deviation after the first frequency regulation.

[0044] 4) After the accelerated frequency modulation, if the frequency returns to the rated value, the frequency modulation ends; if the frequency does not return to the rated value, a secondary frequency modulation is performed, and the frequency modulation ends when the frequency returns to the rated value;

[0045] 5) In step 1), when the disturbance is caused by a three-phase short circuit, the energy storage system switches to a constant frequency control mode. At this time, the output frequency of the energy storage is no longer affected by the active power, that is, no matter how the system power changes during a three-phase short circuit, the output frequency of the energy storage is at the rated value. In order to reduce the power surge caused by the short circuit, the output voltage and current will be limited. Since the system frequency can be maintained unique throughout the network without being affected by the line distance, no matter how far the short circuit point is from the energy storage output end, the system frequency will always be maintained near the rated value;

[0046] 6) When the system short-circuit fault is removed, it switches back to the droop mode. If the short-circuit fault is not removed, the constant frequency mode is maintained until the fault is removed.

[0047] An energy storage system frequency stabilization control device embodiment:

[0048] The present invention also provides a frequency stabilization control device for an energy storage system, comprising:

[0049] The primary frequency modulation module is used to perform a frequency modulation within the primary frequency modulation setting time based on the droop principle if a power disturbance occurs during the steady-state operation of the system and the disturbance is not caused by a three-phase short circuit;

[0050] The acceleration frequency modulation module is used to perform acceleration frequency modulation within the acceleration frequency modulation setting time if the frequency has not been restored to the allowable range after the first frequency modulation. The process of acceleration frequency modulation is as follows: the product of the frequency deviation after the first frequency modulation and the frequency modulation coefficient of the energy storage system is calculated to obtain the acceleration frequency modulation power instruction, and the acceleration frequency modulation power instruction is superimposed on the power instruction after the first frequency modulation;

[0051] The secondary frequency modulation module is used to terminate the frequency modulation if the frequency recovers to the rated value after the acceleration frequency modulation; if the frequency does not recover to the rated value, secondary frequency modulation is performed, and the frequency modulation ends when the frequency recovers to the rated value.

[0052] The above device is actually a computer solution for a frequency stabilization control method of an energy storage system. The specific process of the method has been described in detail in the embodiment of the frequency stabilization control method of an energy storage system, and will not be repeated here.

[0053] An electronic device embodiment:

[0054] The present invention also provides an electronic device, including a memory and a processor, and a computer program stored in the memory and running on the processor, wherein the processor and the memory exchange data via an internal bus, and the processor is used to execute computer program instructions stored in the memory to implement a frequency stabilization control method for an energy storage system. The specific process has been described in detail in the embodiment of the frequency stabilization control method for an energy storage system, and will not be repeated here. Among them, the processor can select a processing device such as a microprocessor MCU, a programmable logic device FPGA, etc., and the memory can select a storage device such as a mobile hard disk, a read-only memory (ROM), and a random access memory (RAM).

[0055] A storage medium embodiment:

[0056] The present invention also provides a storage medium, which can be a storage device such as a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), etc., and a computer program is stored on the storage medium, and the computer program is used to implement the frequency stability control method of the energy storage system when executed by the processor. The specific process of the method has been described in detail in the embodiment of the frequency stability control method of the energy storage system, and will not be repeated here.

[0057] Specific implementation methods are given above, but the present invention is not limited to the described implementation methods. The basic idea of ​​the present invention lies in the above basic scheme. For ordinary technicians in this field, it does not take creative work to design various deformed models, formulas, and parameters according to the teachings of the present invention. Changes, modifications, substitutions, and variations of the implementation methods without departing from the principles and spirit of the present invention still fall within the scope of protection of the present invention.

Claims

1. A frequency stabilization control method for an energy storage system, characterized in that: include: If a power disturbance occurs during the steady-state operation of the system, and the cause of the disturbance is not a three-phase short circuit, the energy storage system will perform a frequency modulation within the frequency modulation setting time based on the droop principle; If the frequency is not restored to the allowable range after the first frequency modulation, the acceleration frequency modulation is performed within the acceleration frequency modulation setting time. The process of the acceleration frequency modulation is as follows: the product of the frequency deviation after the first frequency modulation and the frequency modulation coefficient of the energy storage system is calculated to obtain the acceleration frequency modulation power command, and the acceleration frequency modulation power command is superimposed on the power command after the first frequency modulation; After the accelerated frequency modulation, if the frequency recovers to the rated value, the frequency modulation ends; if the frequency does not recover to the rated value, a secondary frequency modulation is performed, and the frequency modulation ends when the frequency recovers to the rated value.

2. The energy storage system frequency stabilization control method according to claim 1, characterized in that: If the frequency returns to the allowable range after one frequency modulation, the frequency modulation ends.

3. The energy storage system frequency stabilization control method according to claim 1, characterized in that: If the disturbance is caused by a three-phase short circuit, the energy storage system switches to a constant frequency control mode to limit the output voltage and current to keep the frequency near the rated value.

4. The energy storage system frequency stabilization control method according to claim 3, characterized in that: When the energy storage system switches to the constant frequency control mode, if the system short circuit fault is removed, the system switches back to the normal working mode; if the system short circuit fault is not removed, the system maintains the constant frequency mode unchanged until the fault is removed.

5. A frequency stabilization control device for an energy storage system, characterized in that it comprises: The primary frequency modulation module is used to perform a frequency modulation within the primary frequency modulation setting time based on the droop principle if a power disturbance occurs during the steady-state operation of the system and the disturbance is not caused by a three-phase short circuit; The acceleration frequency modulation module is used to perform acceleration frequency modulation within the acceleration frequency modulation setting time if the frequency has not been restored to the allowable range after the first frequency modulation. The process of acceleration frequency modulation is as follows: the product of the frequency deviation after the first frequency modulation and the frequency modulation coefficient of the energy storage system is calculated to obtain the acceleration frequency modulation power instruction, and the acceleration frequency modulation power instruction is superimposed on the power instruction after the first frequency modulation; The secondary frequency modulation module is used to terminate the frequency modulation if the frequency recovers to the rated value after the acceleration frequency modulation; if the frequency does not recover to the rated value, secondary frequency modulation is performed, and the frequency modulation ends when the frequency recovers to the rated value.

6. The energy storage system frequency stabilization control device according to claim 5, characterized in that: If the frequency returns to the allowable range after one frequency modulation, the frequency modulation ends.

7. The frequency stabilization control device for an energy storage system according to claim 5, characterized in that: If the disturbance is caused by a three-phase short circuit, the energy storage system switches to a constant frequency control mode to limit the output voltage and current to keep the frequency near the rated value.

8. The energy storage system frequency stabilization control device according to claim 7, characterized in that: When the energy storage system switches to the constant frequency control mode, if the system short circuit fault is removed, the system switches back to the normal working mode; if the system short circuit fault is not removed, the system maintains the constant frequency mode unchanged until the fault is removed.

9. An electronic device, characterized in that: It comprises a memory and a processor, and a computer program stored in the memory and running on the processor, wherein the processor is used to execute computer program instructions stored in the memory to implement the energy storage system frequency stabilization control method as claimed in any one of claims 1 to 4.

10. A storage medium having a computer program stored thereon, characterized in that: The computer program is used to implement the energy storage system frequency stabilization control method according to any one of claims 1 to 4 when executed by a processor.

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