A hybrid energy storage system primary frequency modulation control method, medium and system

Abstract

The present invention discloses a primary frequency regulation control method, medium, and system for a hybrid energy storage system, comprising: determining the current regulation capability of a coal-fired power generation unit in a normal operating state, wherein the regulation capability includes upward regulation capability and downward regulation capability; calculating the load regulation power required by the power grid based on the current actual frequency deviation of the obtained power grid; controlling the rotation speed of the flywheel energy storage array based on the type of regulation capability possessed by the coal-fired power generation unit, and controlling the flywheel energy storage array to perform primary frequency regulation based on the load regulation power. The present invention can improve the primary frequency regulation capability of the unit while ensuring the frequency regulation amount, reduce the frequent operation of the high-pressure regulating valve of the coal-fired power generation unit, reduce the power fluctuation caused by the step operation of the high-pressure regulating valve of the coal-fired power generation unit, reduce the coal consumption of the coal-fired power generation unit, and improve the utilization rate of the flywheel energy storage array.

Description

Technical Field

[0001] The present invention relates to the technical field of frequency modulation of hybrid energy storage systems, and in particular to a primary frequency modulation control method, medium and system for a hybrid energy storage system. Background Art

[0002] The primary frequency regulation of existing coal-fired power units typically utilizes the thermal storage capacity of the unit's boiler and turbine, responding to frequency action via the turbine's high-pressure control valve to meet primary frequency regulation requirements. This approach requires the turbine's high-pressure control valve to have a fast response speed, high-strength tolerance, and a certain amount of throttling. The increasing proportion of renewable energy in the construction of new power systems has significantly increased grid frequency fluctuations, significantly increasing the frequency and scope of primary frequency regulation for coal-fired units. Primary frequency regulation for coal-fired units is typically implemented at or above 60% of the unit's rated power, and is now gradually extending to the deep peak-shaving period for coal-fired units.

[0003] Flywheel energy storage offers rapid charging and discharging capabilities and quick response, meeting the grid's primary frequency regulation requirements. However, flywheel energy storage has limited capacity and cannot fully meet the primary frequency regulation amplitude requirements of coal-fired power plants. Existing technologies for flywheel energy storage in primary frequency regulation primarily focus on the control logic for primary frequency regulation when a frequency difference occurs in the grid, employing flywheel energy storage and coal-fired units to participate in frequency regulation simultaneously. This approach fails to consider the actual grid conditions and the unique characteristics of flywheel energy storage and coal-fired power primary frequency regulation, failing to fully leverage the advantages of both. Summary of the Invention

[0004] The embodiments of the present invention provide a hybrid energy storage system primary frequency regulation control method, medium and system to solve the problem that existing primary frequency regulation technology does not consider the various characteristics of flywheel energy storage and coal-fired power primary frequency regulation and cannot fully utilize the advantages of both.

[0005] In a first aspect, a method for controlling primary frequency regulation of a hybrid energy storage system is provided, comprising:

[0006] Determining the current regulation capability of the coal-fired power generation unit in a normal operating state, wherein the regulation capability includes: upward regulation capability and downward regulation capability;

[0007] Calculating the load regulation power required by the power grid based on the obtained current actual frequency deviation of the power grid;

[0008] According to the type of regulation capability of the coal-fired power generation unit, the rotation speed of the flywheel energy storage array is controlled, and the flywheel energy storage array is controlled to perform a frequency regulation according to the load regulation power.

[0009] In a second aspect, a computer-readable storage medium is provided, on which computer program instructions are stored; when the computer program instructions are executed by a processor, the primary frequency regulation control method of the hybrid energy storage system as described in the embodiment of the first aspect above is implemented.

[0010] In a third aspect, a hybrid energy storage system primary frequency regulation control system is provided, comprising: a computer-readable storage medium as described in the embodiment of the second aspect above.

[0011] In this way, the embodiment of the present invention can improve the primary frequency regulation capability of the unit while ensuring the frequency regulation amount, reduce the frequent operation of the high-pressure regulating valve of the coal-fired power generation unit, reduce the power fluctuation caused by the step operation of the high-pressure regulating valve of the coal-fired power generation unit, reduce the coal consumption of the coal-fired power generation unit, and improve the utilization rate of the flywheel energy storage array. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0013] Figure 1 This is a flow chart of a primary frequency modulation control method for a hybrid energy storage system according to an embodiment of the present invention. DETAILED DESCRIPTION

[0014] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. All other embodiments derived by ordinary technicians in this field based on the embodiments of the present invention without creative work are within the scope of protection of the present invention.

[0015] The embodiment of the present invention discloses a method for controlling primary frequency modulation of a hybrid energy storage system. Figure 1 As shown, the method of the embodiment of the present invention includes the following steps:

[0016] Step S101: determining the current regulation capability of the coal-fired power generation unit in a normal operating state.

[0017] Among them, the adjustment ability includes: upward adjustment ability and downward adjustment ability.

[0018] The regulation capacity can be determined by the current load of the coal-fired power generation unit and the opening of the current high-pressure regulating valve feedback signal. Therefore, preferably, before this step, the method of the embodiment of the present invention includes:

[0019] Determine the current load of the coal-fired power generation unit and the opening of the current high-pressure valve feedback signal.

[0020] The specific process is as follows:

[0021] (1) If the current load of the coal-fired power generation unit is the maximum load and the opening of the current high-pressure regulating valve feedback signal is greater than the first preset opening, it is determined that the coal-fired power generation unit currently does not have the upward regulation capability.

[0022] The first preset opening can be set based on experience. Generally, the first preset opening is close to the maximum opening.

[0023] (2) If the current load of the coal-fired power generation unit is a steady-burning load, and the opening of the current high-pressure valve feedback signal is less than the second preset opening, it is determined that the coal-fired power generation unit currently does not have the ability to adjust downward.

[0024] It should be understood that the second preset opening is smaller than the first preset opening. The second preset opening can be set based on experience. Generally, the second preset opening is close to the minimum opening.

[0025] (3) If the current load of the coal-fired power generation unit is less than the maximum load and greater than the steady-burning load, and the opening of the current high-pressure valve feedback signal is not greater than the first preset opening and not less than the second preset opening, it is determined that the coal-fired power generation unit currently has the ability to adjust upward and the ability to adjust downward.

[0026] Step S102: Calculate the load regulation power required by the power grid based on the obtained current actual frequency deviation of the power grid.

[0027] Specifically, the calculation formula for the load regulation power required by the power grid is:

[0028]

[0029] Among them, Δp represents the load regulation power, Δf represents the actual frequency deviation, Δf=ff d , f represents the detected frequency deviation of the power grid, f d represents the dead zone frequency of the coal-fired generator set, δ represents the speed inequality of the coal-fired generator set, and p n Indicates the rated power of coal-fired generating units.

[0030] Step S103: According to the type of regulation capability of the coal-fired power generation unit, the speed of the flywheel energy storage array is controlled, and the flywheel energy storage array is controlled to adjust the power according to the load to perform a frequency regulation.

[0031] Specifically, this step includes the following situations:

[0032] (1) If the coal-fired power generation unit currently does not have the ability to adjust upward, the speed of the flywheel energy storage array is controlled to the maximum speed, so that the flywheel energy storage array discharges according to the discharge power being the absolute value of the load adjustment power.

[0033] For example, consider a 600MW generator set equipped with a 36MW flywheel energy storage array. When the coal-fired generator set is operating at its full 600MW load (maximum load), and the high-pressure valve feedback signal is fully open (inherently greater than the first preset opening), the coal-fired generator set has no upward adjustment capability. The flywheel energy storage array is adjusted to its maximum speed, allowing it to discharge, not charge.

[0034] The detected grid frequency deviation is -0.1833 Hz, while the actual frequency deviation is -0.15 Hz. Using the formula in step S102, the absolute value of the required upward load regulation power is calculated to be 36 MW. This load command is then transmitted to the flywheel energy storage array, which discharges and outputs 36 MW.

[0035] (2) If the coal-fired power generation unit currently does not have the ability to adjust downward, the speed of the flywheel energy storage array is controlled to the minimum speed, so that the flywheel energy storage array is charged according to the charging power being the absolute value of the load adjustment power.

[0036] For example, consider a 600MW generator set equipped with a 36MW flywheel energy storage array. When the coal-fired generator set is operating at a steady-state load of 200MW, the high-pressure valve feedback signal is already at its minimum opening (i.e., necessarily less than the second preset opening). The coal-fired generator set has no ability to adjust downward. The flywheel energy storage array is adjusted to its minimum speed, allowing it to only charge, not discharge.

[0037] The detected grid frequency deviation is 0.1833 Hz, while the actual frequency deviation is 0.15 Hz. Using the formula in step S102, the absolute value of the required downward load regulation power is calculated to be 36 MW. This load command is then transmitted to the flywheel energy storage array, which then charges and absorbs 36 MW.

[0038] (3) If the coal-fired power generation unit currently has the ability to adjust upward and downward, the speed of the flywheel energy storage array is controlled to be an intermediate speed, and the flywheel energy storage array is controlled to charge and discharge based on the positive and negative nature of the current actual frequency deviation according to the relationship between the maximum frequency deviation that the flywheel energy storage array can provide and the absolute value of the current actual frequency deviation.

[0039] The intermediate rotational speed is less than the maximum rotational speed of the flywheel energy storage array and greater than the minimum rotational speed of the flywheel energy storage array.

[0040] The maximum frequency deviation that the flywheel energy storage array can provide can be obtained through the following process:

[0041] The maximum frequency deviation that can be provided by the flywheel energy storage array is obtained by multiplying the historical frequency deviation that occurs most frequently in the historical frequency deviations that occur within the preset historical time period by a preset percentage.

[0042] The preset historical time period can be determined based on experience, for example, the preset historical time period is 1 year. The historical frequency deviation can be obtained through PMU data analysis. The preset percentage can be determined based on experience, for example, the preset percentage is 80%. By determining the maximum frequency deviation that the flywheel energy storage array can provide, the model of the selected flywheel energy storage array can be determined to meet the power requirements that can be provided. The power calculation formula is as described above, that is, Where Δp p represents the power that the flywheel energy storage array can provide, f p represents the maximum frequency deviation that the flywheel energy storage array can provide, δ represents the speed inequality, and p n Indicates the rated power of coal-fired generating units.

[0043] For example, consider a 600MW generator set equipped with a 36MW flywheel energy storage array. When the coal-fired generator set operates at a 400MW load and the high-pressure valve feedback signal opening is at an intermediate value, between the first and second preset openings, the coal-fired generator set has the ability to adjust upward and downward. Adjusting the flywheel energy storage array's speed to the intermediate speed allows it to both charge and discharge, with the specific charge or discharge behavior determined by the positive or negative value of the actual frequency deviation.

[0044] For this situation, there are several specific control methods including the following:

[0045] ① If the absolute value of the current actual frequency deviation is not greater than the maximum frequency deviation that the flywheel energy storage array can provide, and the current actual frequency deviation is negative, the flywheel energy storage array is controlled to discharge according to the absolute value of the load adjustment power at the discharge power.

[0046] Take a 600MW generator set equipped with a 36MW flywheel energy storage array as an example. The detected frequency deviation of the power grid is -0.1833Hz, and the actual frequency deviation is -0.15Hz, whose absolute value is not greater than the maximum frequency deviation f that the flywheel energy storage array can provide. p The absolute value of the required upward load regulation power calculated by the calculation formula in step S102 is 36MW. At this time, this load instruction is transmitted to the flywheel energy storage array, and the flywheel energy storage array discharges and outputs 36MW.

[0047] ② If the absolute value of the current actual frequency deviation is not greater than the maximum frequency deviation that the flywheel energy storage array can provide, and the current actual frequency deviation is positive, the flywheel energy storage array is controlled to charge according to the charging power being the absolute value of the load adjustment power.

[0048] Take a 600MW generator set equipped with a 36MW flywheel energy storage array as an example. The detected frequency deviation of the power grid is 0.1833Hz, and the actual frequency deviation is 0.15Hz, whose absolute value is not greater than the maximum frequency deviation f that the flywheel energy storage array can provide. p The absolute value of the required downward load regulation power calculated by the calculation formula in step S102 is 36MW. At this time, this load instruction is transmitted to the flywheel energy storage array, and the flywheel energy storage array charges and absorbs 36MW.

[0049] ③ If the absolute value of the current actual frequency deviation is greater than the maximum frequency deviation that the flywheel energy storage array can provide, and the current actual frequency deviation is negative, the flywheel energy storage array is controlled to discharge according to the discharge power corresponding to the maximum frequency deviation that the flywheel energy storage array can provide, and the coal-fired power generation unit is controlled to increase its own output power according to the power corresponding to the difference between the absolute value of the current actual frequency deviation and the maximum frequency deviation that the flywheel energy storage array can provide.

[0050] It should be understood that since the flywheel energy storage array can both charge and discharge at this time, the discharge power and charging power corresponding to its maximum frequency deviation are equal, both being half of the total power corresponding to its maximum frequency deviation.

[0051] Take a 600MW generator set equipped with a 36MW flywheel energy storage array as an example. The detected frequency deviation of the power grid is -0.1833Hz, and the actual frequency deviation is -0.15Hz, whose absolute value is greater than the maximum frequency deviation f that the flywheel energy storage array can provide. p The absolute value of the required upward load regulation power calculated by the calculation formula in step S102 is 36MW. At this time, this load instruction is transmitted to the flywheel energy storage array, and the flywheel energy storage array discharges and outputs the maximum frequency deviation f p The corresponding discharge power is 18MW, and the remaining 18MW is completed by the steam turbine speed control system of the coal-fired generator set, which increases the output power of the coal-fired generator set by 18MW.

[0052] In this process, the high-pressure door action rate is also reduced.

[0053] ④ If the absolute value of the current actual frequency deviation is greater than the maximum frequency deviation that the flywheel energy storage array can provide, and the current actual frequency deviation is positive, the flywheel energy storage array is controlled to charge according to the charging power corresponding to the maximum frequency deviation that the flywheel energy storage array can provide, and the coal-fired power generation unit is controlled to reduce its own output power according to the difference between the absolute value of the current actual frequency deviation and the maximum frequency deviation that the flywheel energy storage array can provide.

[0054] Take a 600MW generator set equipped with a 36MW flywheel energy storage array as an example. The detected frequency deviation of the power grid is 0.1833Hz, and the actual frequency deviation is 0.15Hz, whose absolute value is greater than the maximum frequency deviation f that the flywheel energy storage array can provide. p The absolute value of the required downward load regulation power calculated by the calculation formula in step S102 is 36MW. At this time, this load instruction is transmitted to the flywheel energy storage array, and the flywheel energy storage array charges to absorb the maximum frequency deviation f p The corresponding charging power is 18MW, and the remaining 18MW is completed by the turbine speed control system of the coal-fired generator set, reducing the output power of the coal-fired generator set by 18MW.

[0055] In this process, the high-pressure door action rate is also reduced.

[0056] Through the above-mentioned primary frequency regulation method, taking the unit equipped with flywheel energy storage with a rated capacity of 36MW as an example, 1MW is theoretically equivalent to 1.229 tons of standard coal, which can save 44.244 (36*1.229=44.244) tons of standard coal.

[0057] Preferably, before step S101, the following steps may be used to determine whether the coal-fired power generation unit is in a normal operating state:

[0058] (1) Collect pressure, temperature and flow signals of coal-fired power generation units.

[0059] Specifically, the pressure signal includes: a main steam pressure signal and a condenser pressure signal. The temperature signal includes: a main steam temperature signal and a condenser temperature signal. The flow signal includes: a main steam flow signal and a condenser flow signal.

[0060] (2) Determine whether there are alarm signals in the pressure, temperature and flow signals of the coal-fired power generation unit.

[0061] (3) If there are no alarm signals, it is determined that the coal-fired power generation unit is in normal operation.

[0062] That is, if at least one signal has an alarm signal, the coal-fired unit is in an abnormal operating state. The abnormal condition should be eliminated first to make the coal-fired unit operate normally, and then the frequency modulation should be performed using the method of the embodiment of the present invention.

[0063] An embodiment of the present invention further discloses a computer-readable storage medium having computer program instructions stored thereon; when the computer program instructions are executed by a processor, the primary frequency modulation control method of the hybrid energy storage system as described in the above embodiment is implemented.

[0064] An embodiment of the present invention further discloses a primary frequency regulation control system of a hybrid energy storage system, comprising: a computer-readable storage medium as described in the above embodiment.

[0065] In summary, the embodiments of the present invention adjust the state of the flywheel energy storage array according to the operating load range of the unit, thereby improving the primary frequency regulation capability of the unit and ensuring the frequency regulation amount, reducing the frequent operation of the high-pressure regulating valve of the coal-fired power generation unit, reducing the power fluctuation caused by the step operation of the high-pressure regulating valve of the coal-fired power generation unit, reducing the coal consumption of the coal-fired power generation unit, and improving the utilization rate of the flywheel energy storage array.

[0066] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A primary frequency modulation control method for a hybrid energy storage system, characterized in that: include: Determining the current regulation capability of the coal-fired power generation unit in a normal operating state, wherein the regulation capability includes: upward regulation capability and downward regulation capability; Calculating the load regulation power required by the power grid based on the obtained current actual frequency deviation of the power grid; Controlling the speed of the flywheel energy storage array according to the type of regulation capability of the coal-fired power generation unit, and controlling the flywheel energy storage array to perform a frequency modulation according to the load regulation power; The step of controlling the flywheel energy storage array to perform a frequency modulation according to the load power regulation comprises: If the coal-fired power generation unit currently does not have the ability to adjust upward, the speed of the flywheel energy storage array is controlled to be the maximum speed, so that the flywheel energy storage array discharges according to the discharge power being the absolute value of the load adjustment power; If the coal-fired power generation unit currently does not have the ability to adjust downward, the speed of the flywheel energy storage array is controlled to be the minimum speed, so that the flywheel energy storage array is charged according to the charging power being the absolute value of the load adjustment power; If the coal-fired power generation unit currently has the ability to adjust upward and downward, the speed of the flywheel energy storage array is controlled to be an intermediate speed, and the flywheel energy storage array is controlled to charge and discharge based on the positive or negative sign of the current actual frequency deviation according to the relationship between the maximum frequency deviation that the flywheel energy storage array can provide and the absolute value of the current actual frequency deviation, wherein the intermediate speed is less than the maximum speed of the flywheel energy storage array and greater than the minimum speed of the flywheel energy storage array; The calculation formula for the load regulation power required by the power grid is: ； in, Indicates load regulation power, Indicates the actual frequency deviation, , f Indicates the detected frequency deviation of the power grid, Indicates the dead-band frequency of coal-fired generator sets, Indicates the speed inequality of the coal-fired generator set. Indicates the rated power of coal-fired generating units.

2. The primary frequency modulation control method of the hybrid energy storage system according to claim 1, characterized in that: Before the step of determining the current regulation capability of the coal-fired power generation unit in a normal operating state, the method includes: Determine the current load of the coal-fired power generation unit and the opening of the current high-pressure regulating valve feedback signal.

3. The primary frequency modulation control method of the hybrid energy storage system according to claim 2, characterized in that: The step of determining the current regulation capability of the coal-fired power generation unit in a normal operating state includes: If the current load of the coal-fired power generation unit is the maximum load, and the opening of the current high-pressure regulating valve feedback signal is greater than the first preset opening, it is determined that the coal-fired power generation unit currently does not have the upward regulation capability; If the current load of the coal-fired power generation unit is a steady-burning load and the opening of the current high-pressure regulating valve feedback signal is less than a second preset opening, it is determined that the coal-fired power generation unit currently does not have the ability to adjust downward; If the current load of the coal-fired power generation unit is less than the maximum load and greater than the stable combustion load, and the opening of the current high-pressure valve feedback signal is not greater than the first preset opening and not less than the second preset opening, it is determined that the coal-fired power generation unit currently has the ability to adjust upward and downward.

4. The primary frequency modulation control method of the hybrid energy storage system according to claim 1, characterized in that: The step of controlling the flywheel energy storage array to charge and discharge based on the positive or negative value of the current actual frequency deviation according to the magnitude relationship between the maximum frequency deviation that can be provided by the flywheel energy storage array and the absolute value of the current actual frequency deviation comprises: If the absolute value of the current actual frequency deviation is not greater than the maximum frequency deviation that can be provided by the flywheel energy storage array, and the current actual frequency deviation is negative, controlling the flywheel energy storage array to discharge according to the discharge power being the absolute value of the load regulation power; If the absolute value of the current actual frequency deviation is not greater than the maximum frequency deviation that can be provided by the flywheel energy storage array, and the current actual frequency deviation is positive, controlling the flywheel energy storage array to charge according to the charging power being the absolute value of the load regulation power; If the absolute value of the current actual frequency deviation is greater than the maximum frequency deviation that can be provided by the flywheel energy storage array, and the current actual frequency deviation is negative, the flywheel energy storage array is controlled to discharge according to the discharge power corresponding to the maximum frequency deviation that can be provided by the flywheel energy storage array, and the coal-fired power generation unit is controlled to increase its own output power according to the power corresponding to the difference between the absolute value of the current actual frequency deviation and the maximum frequency deviation that can be provided by the flywheel energy storage array; If the absolute value of the current actual frequency deviation is greater than the maximum frequency deviation that can be provided by the flywheel energy storage array, and the current actual frequency deviation is positive, the flywheel energy storage array is controlled to be charged according to the charging amount corresponding to the maximum frequency deviation that can be provided by the flywheel energy storage array, and the coal-fired power generation unit is controlled to reduce its own output power according to the difference between the absolute value of the current actual frequency deviation and the maximum frequency deviation that can be provided by the flywheel energy storage array.

5. The primary frequency modulation control method of the hybrid energy storage system according to claim 1, characterized in that: Also includes: The maximum frequency deviation that can be provided by the flywheel energy storage array is obtained by multiplying the historical frequency deviation that occurs most frequently in the historical frequency deviations that occur within a preset historical time period by a preset percentage.

6. The primary frequency modulation control method of the hybrid energy storage system according to claim 1, characterized in that: Before the step of determining the current regulation capability of the coal-fired power generation unit in a normal operating state, the method includes: Collecting pressure, temperature and flow signals of the coal-fired power generation unit; Determining whether there are alarm signals in the pressure, temperature and flow signals of the coal-fired power generation unit; If there is no alarm signal, it is determined that the coal-fired power generation unit is in normal operation.

7. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer program instructions; when the computer program instructions are executed by the processor, the primary frequency regulation control method of the hybrid energy storage system according to any one of claims 1 to 6 is implemented.

8. A hybrid energy storage system primary frequency modulation control system, characterized in that: include: The computer-readable storage medium of claim 7.

Images