A method, device, equipment and readable storage medium for adjusting power grid frequency

Abstract

The present application discloses a method, device, equipment and readable storage medium for adjusting the frequency of a power grid, including: obtaining the original frequency of the power grid; determining the control mode of the power grid according to the original frequency; if the control mode of the power grid is an inertia response mode, calculating the actual frequency modulation power of the power grid according to the original frequency, the actual frequency modulation power is determined according to the secondary change rate of the original frequency, and the secondary change rate of the original frequency is used to indicate the change speed of the change rate of the original frequency; adjusting the frequency of the power grid according to the actual frequency modulation power. In the present application, when the control mode of the power grid is an inertia response mode, the actual frequency modulation power is calculated according to the secondary change rate of the original frequency of the power grid, and the frequency of the power grid is adjusted according to the actual frequency modulation power, that is, the change speed of the change rate of the original frequency of the power grid is taken into account when adjusting the frequency of the power grid, so that the adjustment of the power grid frequency can be achieved more accurately, thereby improving the accuracy of the power grid frequency adjustment.

Description

Technical Field

[0001] The present application relates to the field of power systems, and more specifically, to a method, device, equipment and readable storage medium for adjusting power grid frequency. Background Art

[0002] my country is accelerating the construction of a new power system with new energy as the main body. To gradually reduce the use of fossil energy, new energy should be developed on a larger scale. In this context, the proportion of synchronous units with rotational kinetic energy reserves will drop significantly, and new energy will be connected to the power system at a higher proportion. However, new energy sources such as wind power and photovoltaics that use conventional control cannot provide frequency support such as inertia and primary frequency regulation like traditional synchronous generator sets. After replacing traditional synchronous generator sets, new energy will worsen the frequency dynamics of the system under power disturbances. This will cause the equivalent inertia of the power system to continue to weaken and its ability to resist frequency disturbances to deteriorate, causing potential serious frequency accidents. Therefore, it is necessary to make timely frequency adjustments when the frequency of the power system is disturbed to improve the stability of the power system.

[0003] However, the current grid frequency adjustment method is usually based on the rate of change of the grid frequency, which has low accuracy and cannot further improve the stability of the grid. Summary of the invention

[0004] The embodiments of the present application provide a method, device, equipment and readable storage medium for adjusting the frequency of a power grid, which can improve the accuracy of the frequency adjustment of the power grid and thus improve the stability of the power grid.

[0005] In view of this, an embodiment of the present application provides a method for adjusting power grid frequency, the method comprising:

[0006] Get the original frequency of the power grid;

[0007] determining a control mode of the power grid according to the original frequency;

[0008] If the control mode of the power grid is the inertia response mode, the actual frequency modulation power of the power grid is calculated according to the original frequency, and the actual frequency modulation power is determined according to the quadratic change rate of the original frequency, and the quadratic change rate of the original frequency is used to indicate the change speed of the change rate of the original frequency;

[0009] The frequency of the power grid is adjusted according to the actual frequency modulation power.

[0010] Optionally, the calculating according to the original frequency to obtain the actual frequency modulation power of the power grid includes:

[0011] Calculate the rate of change of the original frequency and the frequency change amount of the original frequency according to the original frequency;

[0012] Calculating the secondary change rate of the original frequency according to the change rate of the original frequency;

[0013] Obtaining the rated frequency modulation power of the power grid, the rated frequency of the power grid, the inertia time constant and the rated active power of the converter;

[0014] The actual frequency modulation power of the power grid is calculated according to the change rate of the original frequency, the secondary change rate of the original frequency, the frequency change of the original frequency, the rated frequency modulation power of the power grid, the rated frequency of the power grid, the inertia time constant and the rated active power of the converter.

[0015] Optionally, calculating the actual frequency modulation power of the power grid according to the change rate of the original frequency, the secondary change rate of the original frequency, the frequency change of the original frequency, the rated frequency modulation power of the power grid, the rated frequency of the power grid, the inertia time constant and the rated active power of the converter includes:

[0016] If the product of the quadratic change rate of the original frequency and the change rate of the original frequency is greater than zero, the power adjustment amount is calculated according to the change rate of the original frequency, the quadratic change rate of the original frequency, the frequency change amount of the original frequency, the inertia time constant and the rated active power of the converter;

[0017] If the product of the quadratic change rate of the original frequency and the change rate of the original frequency is less than zero, the power adjustment amount is calculated according to the change rate of the original frequency, the frequency change of the original frequency, the inertia time constant and the rated active power of the converter;

[0018] The actual frequency regulation power of the power grid is obtained by calculation according to the power adjustment amount and the rated frequency regulation power of the power grid.

[0019] Optionally, determining a control mode of a power grid according to the original frequency includes:

[0020] Calculating the frequency change of the original frequency and the change rate of the original frequency according to the original frequency of the power grid;

[0021] If the product of the frequency change of the original frequency and the change rate of the original frequency is greater than zero, and the absolute value of the frequency change of the original frequency is greater than the inertia response critical value, then determining that the control mode of the power grid is the inertia response mode;

[0022] If the product of the frequency change of the original frequency and the change rate of the original frequency is greater than zero, and the absolute value of the frequency change of the original frequency is greater than the inertia response critical value, the control mode of the power grid is determined to be the normal control mode.

[0023] Optionally, after adjusting the frequency of the power grid according to the actual frequency modulation power, the method further includes:

[0024] Obtaining an adjusted frequency of the power grid;

[0025] If the adjustment frequency of the power grid meets the exit condition of the inertia response mode, determining the adjustment step size according to the actual frequency modulation power;

[0026] Adjust the actual frequency modulation power according to the adjustment step to obtain a target frequency modulation power;

[0027] Adjusting the frequency of the power grid according to the target frequency modulation power;

[0028] Return to the step of adjusting the actual frequency modulation power according to the adjustment step to obtain the target frequency modulation power, until the target frequency modulation power is equal to the rated frequency modulation power of the power grid.

[0029] The present application also provides a power grid frequency adjustment device, the device comprising:

[0030] An acquisition unit, used for acquiring the original frequency of the power grid;

[0031] a determining unit, configured to determine a control mode of a power grid according to the original frequency;

[0032] a calculation unit, configured to calculate, if the control mode of the power grid is an inertia response mode, an actual frequency modulation power of the power grid according to the original frequency, wherein the actual frequency modulation power is determined according to a quadratic change rate of the original frequency, wherein the quadratic change rate of the original frequency is used to indicate a change speed of a change rate of the original frequency;

[0033] A frequency modulation unit is used to adjust the frequency of the power grid according to the actual frequency modulation power.

[0034] Optionally, the calculation unit is used to calculate the change rate of the original frequency and the frequency change amount of the original frequency according to the original frequency;

[0035] Calculating the secondary change rate of the original frequency according to the change rate of the original frequency;

[0036] Obtaining the rated frequency modulation power of the power grid, the rated frequency of the power grid, the inertia time constant and the rated active power of the converter;

[0037] The actual frequency modulation power of the power grid is calculated according to the change rate of the original frequency, the secondary change rate of the original frequency, the frequency change of the original frequency, the rated frequency modulation power of the power grid, the rated frequency of the power grid, the inertia time constant and the rated active power of the converter.

[0038] Optionally, the computing unit is specifically configured to:

[0039] If the product of the quadratic change rate of the original frequency and the change rate of the original frequency is greater than zero, the power adjustment amount is calculated according to the change rate of the original frequency, the quadratic change rate of the original frequency, the frequency change amount of the original frequency, the inertia time constant and the rated active power of the converter;

[0040] If the product of the quadratic change rate of the original frequency and the change rate of the original frequency is less than zero, the power adjustment amount is calculated according to the change rate of the original frequency, the frequency change of the original frequency, the inertia time constant and the rated active power of the converter;

[0041] The actual frequency regulation power of the power grid is obtained by calculation according to the power adjustment amount and the rated frequency regulation power of the power grid.

[0042] The embodiment of the present application also provides a computer device, including: a memory, a processor, and a bus system;

[0043] Wherein, the memory is used to store programs;

[0044] The processor is used to execute the program in the memory to implement any one of the above-mentioned power grid frequency adjustment methods;

[0045] The bus system is used to connect the memory and the processor so that the memory and the processor can communicate with each other.

[0046] An embodiment of the present application also provides a computer-readable storage medium storing instructions, which, when executed on a computer, enables the computer to execute any one of the power grid frequency adjustment methods described above.

[0047] The embodiment of the present application provides a method for adjusting the frequency of a power grid, including: obtaining the original frequency of the power grid; determining the control mode of the power grid according to the original frequency; if the control mode of the power grid is an inertia response mode, calculating the actual frequency modulation power of the power grid according to the original frequency, the actual frequency modulation power is determined according to the secondary change rate of the original frequency, and the secondary change rate of the original frequency is used to represent the change speed of the change rate of the original frequency; adjusting the frequency of the power grid according to the actual frequency modulation power. It can be seen that in the present application, when the control mode of the power grid is an inertia response mode, the actual frequency modulation power is calculated according to the secondary change rate of the original frequency of the power grid, and the frequency of the power grid is adjusted according to the actual frequency modulation power, that is, the change speed of the change rate of the original frequency of the power grid is considered when adjusting the power grid frequency, so that the adjustment of the power grid frequency can be achieved more accurately, thereby improving the accuracy of the power grid frequency adjustment, and then improving the stability of the power grid. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0049] Figure 1 A schematic diagram of a flow chart of a method for adjusting power grid frequency provided in an embodiment of the present application;

[0050] Figure 2 A schematic diagram of the structure of a power grid frequency adjustment system provided in an embodiment of the present application;

[0051] Figure 3 A schematic diagram of a flow chart of an EMS control mode provided in an embodiment of the present application;

[0052] Figure 4 A schematic diagram of the relationship between the charging coefficient K1 and the remaining power SOC in an EMS control mode provided in an embodiment of the present application;

[0053] Figure 5 A schematic diagram of the relationship between the discharge coefficient K2 and the remaining power SOC in an EMS control mode provided in an embodiment of the present application;

[0054] Figure 6 A schematic diagram of the structure of a power grid frequency adjustment device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0055] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0056] The terms "first", "second", "third", "fourth", etc. (if any) in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments described herein can be implemented in an order other than that illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0057] my country is accelerating the construction of a new power system with new energy as the main body. To gradually reduce the use of fossil energy, new energy should be developed on a larger scale. In this context, the proportion of synchronous units with rotational kinetic energy reserves will drop significantly, and new energy will be connected to the power system at a higher proportion. However, new energy sources such as wind power and photovoltaics that use conventional control cannot provide frequency support such as inertia and primary frequency regulation like traditional synchronous generator sets. After replacing traditional synchronous generator sets, new energy will worsen the frequency dynamics of the system under power disturbances. This will cause the equivalent inertia of the power system to continue to weaken and its ability to resist frequency disturbances to deteriorate, causing potential serious frequency accidents. Therefore, it is necessary to make timely frequency adjustments when the frequency of the power system is disturbed to improve the stability of the power system.

[0058] However, the current grid frequency adjustment method is usually based on the rate of change of the grid frequency, which has low accuracy and cannot further improve the stability of the grid.

[0059] Therefore, in response to the above problems, the embodiments of the present application provide a power grid frequency adjustment method, device, equipment and readable storage medium, which can improve the accuracy of power grid frequency adjustment and thereby improve the stability of the power grid.

[0060] See also Figure 1 A grid frequency adjustment method provided in an embodiment of the present application can be applied to a power conversion system (PCS) controller, and specifically includes the following steps.

[0061] S101. Obtain the original frequency of the power grid.

[0062] In this embodiment, the original frequency of the power grid can be obtained first. It can be understood that Figure 2 As shown, the PCS controller can sample the grid voltage through the voltage sensor, and then obtain the original frequency of the grid through further calculation, which can be represented by f. It can also further obtain the rated frequency modulation power P of the grid. EMS , that is, the active power set by the Energy Management System (EMS) controller, which can be positive or negative. A positive value indicates that the energy storage battery pack is discharging, and a negative value indicates that the energy storage battery pack is charging. The rated frequency f of the power grid can also be obtained. N , inertia time constant T j and the rated active power P of the converter, i.e. the energy storage battery pack N .

[0063] S102: Determine a control mode of the power grid according to the original frequency.

[0064] In this embodiment, after the original frequency of the power grid is obtained, the control mode of the power grid can be determined according to the original frequency. It can be understood that the PCS controller can judge the state of the power grid according to the original frequency of the power grid, that is, it can judge whether the power grid is in a stable state or an unstable state, so as to adopt different control modes to control the power grid, thereby improving the accuracy of the power grid frequency adjustment and further improving the stability of the power grid. Specifically, if the power grid is in a stable state, the control mode of the power grid can be a normal control mode, that is, an EMS control mode; if the power grid is in an unstable state, the control mode of the power grid can be an inertia response mode.

[0065] In one possible implementation, the frequency change of the original frequency and the rate of change of the original frequency can be calculated according to the original frequency of the power grid; if the product of the frequency change of the original frequency and the rate of change of the original frequency is greater than zero, and the absolute value of the frequency change of the original frequency is greater than the inertia response critical value, then the control mode of the power grid is determined to be the inertia response mode; if the product of the frequency change of the original frequency and the rate of change of the original frequency is not greater than zero, and the absolute value of the frequency change of the original frequency is greater than the inertia response critical value, then the control mode of the power grid is determined to be the normal control mode.

[0066] It can be understood that the frequency change Δf and the change rate of the original frequency can be calculated based on the original frequency f of the power grid. Where Δf = ff N , f N is the rated frequency of the power grid. and |Δf| > f dead , where f dead is a preset critical value of inertia response, that is, when the product of the frequency change of the original frequency and the change rate of the original frequency is greater than zero, and the absolute value of the frequency change of the original frequency is greater than the critical value of inertia response, it can be explained that the grid state is an unstable state at this time, and the control mode of the grid can be the inertia response mode; if it does not meet and |Δf| > f dead , where f dead is a preset critical value of inertia response, that is, when the product of the frequency change of the original frequency and the change rate of the original frequency is not greater than zero, and the absolute value of the frequency change of the original frequency is greater than the critical value of inertia response, it can be explained that the grid state is a stable state at this time, and the control mode of the grid can be the ordinary control mode, that is, the EMS control mode.

[0067] It should be noted that as Figure 3 shown, when the control mode of the grid is the EMS control mode, the PCS controller can receive the active and reactive power commands set by the EMS controller, that is, the rated frequency modulation power P EMS of the grid. The PCS calculates the grid frequency f by sampling the three-phase voltage of the grid, saves the grid frequency into the array F[N], that is, F[i] = f, and calculates the frequency change rate where i is the current count value, i is automatically incremented by 1 each time it is operated, j is the value corresponding to the time window Δt for calculating the frequency change rate, and the frequency change rate is saved into the array F1[N]. The PCS controller communicates with the new energy battery pack to obtain the remaining battery power SOC value, and limits the charge and discharge power according to the battery SOC value. In order to limit the maximum discharge power at the end of battery discharge, the maximum charge power can be limited at the end of battery charge to ensure that the charge and discharge power of the battery is limited within a safe value at the end of charge and discharge, which can extend the life of the battery and ensure the safety and reliability of the battery.

[0068] Specifically, when B1 <= SOC <= B2, the energy storage battery pack can charge and discharge at the rated frequency modulation power, the charge coefficient k1 = 1, and the discharge coefficient k2 = 1, where B1 is the lower limit constant of the SOC for charge and discharge at the rated frequency modulation power, and B2 is the upper limit constant of the SOC for charge and discharge at the rated frequency modulation power; when B2 < SOC, the charge coefficient k1 = [(1 - SOC) / (1 - B2)]^n, the discharge coefficient k2 = 1, the charge is subject to a certain power limit, and the discharge is not affected; when SOC < B1, the discharge coefficient k2 = (SOC / B1)^n, the charge coefficient k1 = 1, the discharge is subject to a certain power limit, and the charge is not affected. n is a constant. When n = 3, the curves of the charge coefficient and the discharge coefficient are plotted respectively as Figure 4 、 Figure 5As shown, it can be seen from the figure that the charge and discharge coefficient changes continuously, and the battery charge and discharge control is relatively friendly.

[0069] EMS sets power P EMS >=0, that is, discharge, when P EMS >K2*P Bat_N , the power set by EMS is greater than the power limit of battery discharge, and the power given by PCS is executed according to the limited power of the battery, that is, P ref =K2*P Bat_N (P Bat_N is the rated power value of the battery); when P EMS <K2*P Bat_N , the power set by EMS is not greater than the power limit of the battery, and the PCS responds to the EMS power command, that is, P ref =P EMS ; EMS has power P EMS <0, that is, charging, when P EMS <-K1*P Bat_N , the power set by EMS is greater than the power limit of battery charging, and the power given by PCS is executed according to the limited power of the battery, that is, P ref =-K1*P Bat_N When P EMS >-K1*P Bat_N , the power set by EMS is not greater than the power limit of the battery, and the PCS responds to the EMS power command, that is, P ref =P EMS .

[0070] S103: If the control mode of the power grid is an inertia response mode, obtain the actual frequency modulation power of the power grid according to the original frequency.

[0071] In this embodiment, if it is determined that the control mode of the power grid is the inertia response mode, the actual frequency modulation power of the power grid can be calculated according to the original frequency. Among them, the actual frequency modulation power is determined according to the quadratic change rate of the original frequency, and the quadratic change rate of the original frequency is used to indicate the change speed of the change rate of the original frequency. It can be understood that when the control mode of the power grid is the inertia response mode, the change rate of the original frequency can be first calculated according to the original frequency, and then the quadratic change rate of the original frequency can be calculated according to the change rate of the original frequency, and finally the actual frequency modulation power of the power grid can be calculated based on the quadratic change rate of the original frequency, so that the frequency of the power grid can be adjusted according to the actual frequency modulation power, that is, the change speed of the change rate of the original frequency of the power grid is taken into account when adjusting the power grid frequency, and the adjustment of the power grid frequency can be realized more accurately, thereby improving the accuracy of the power grid frequency adjustment, and then improving the stability of the power grid.

[0072] In one possible implementation, the rate of change of the original frequency and the frequency change of the original frequency can be calculated based on the original frequency; the secondary rate of change of the original frequency can be calculated based on the rate of change of the original frequency; the rated frequency modulation power of the power grid, the rated frequency of the power grid, the inertia time constant and the rated active power of the converter can be obtained; the actual frequency modulation power of the power grid can be calculated based on the rate of change of the original frequency, the secondary rate of change of the original frequency, the frequency change of the original frequency, the rated frequency modulation power of the power grid, the rated frequency of the power grid, the inertia time constant and the rated active power of the converter.

[0073] It is understandable that the rate of change of the original frequency can be calculated based on the original frequency f of the power grid. And the frequency change Δf of the original frequency, specifically, the original frequency f can be saved in the array F[N], that is, F[i] = f, and then according to Where i is the current count value, which is automatically increased by 1 each time it is calculated, and j is the value corresponding to the time window Δt of the frequency change rate, which is used to calculate the change rate of the original frequency. The frequency change of the original frequency is calculated as Δf = ff N , f N is the rated frequency of the power grid. Then according to the change rate of the original frequency Calculate the quadratic rate of change of the original frequency The specific formula is Then the rated frequency modulation power P of the power grid can be obtained EMS , the rated frequency of the power grid f N , Inertia time constant T j and the rated active power P of the converter, i.e. the energy storage battery pack N , and finally the rate of change of the original frequency can be The quadratic rate of change of the original frequency The frequency change of the original frequency Δf, the rated frequency modulation power P of the power grid EMS , the rated frequency of the power grid f N , Inertia time constant T j and the rated active power P of the converter, i.e. the energy storage battery pack N The actual frequency modulation power of the power grid is calculated so that the frequency of the power grid can be adjusted according to the actual frequency modulation power. That is, the speed of change of the rate of change of the original frequency of the power grid is taken into account when adjusting the frequency of the power grid, and the frequency of the power grid can be adjusted more accurately, thereby improving the accuracy of the frequency adjustment of the power grid and further improving the stability of the power grid.

[0074] In one possible implementation, if the product of the quadratic change rate of the original frequency and the change rate of the original frequency is greater than zero, the power adjustment amount can be calculated based on the change rate of the original frequency, the quadratic change rate of the original frequency, the frequency change of the original frequency, the inertia time constant and the rated active power of the converter; if the product of the quadratic change rate of the original frequency and the change rate of the original frequency is less than zero, the power adjustment amount can be calculated based on the change rate of the original frequency, the frequency change of the original frequency, the inertia time constant and the rated active power of the converter; the actual frequency modulation power of the power grid can be calculated based on the power adjustment amount and the rated frequency modulation power of the power grid.

[0075] It is understandable that the power adjustment ΔP can be calculated first, and then the power adjustment ΔP and the rated frequency modulation power P of the power grid can be used to adjust the power. EMS To calculate the actual frequency modulation power P of the power grid ref If the product of the quadratic rate of change of the original frequency and the rate of change of the original frequency is greater than zero, that is, When , it means that the grid frequency is in a positive growth or negative growth situation, that is, the grid frequency is in a serious unstable state. At this time, it is necessary to suppress the serious unstable state of the grid frequency as soon as possible, that is, the new energy converter needs to provide a large inertia power to respond to the grid frequency instability. At this time, the formula for calculating the power adjustment ΔP can be:

[0076]

[0077] Among them, m1 and m2 are constants. is the rate of change of the original frequency, is the quadratic change rate of the original frequency, Δf is the frequency change of the original frequency, f N is the rated frequency of the power grid, T j is the inertia time constant, the rated active power P of the converter, i.e. the energy storage battery pack N is the rated active power of the converter. When the grid frequency is seriously unstable, the power adjustment ΔP of the inertia response is and (1+|Δf|) grow exponentially, and the power adjustment ΔP is related to is positively correlated with Δf, Used to suppress rapid frequency changes, (1+|Δf|) m2 Used to suppress frequency deviation.

[0078] If the product of the quadratic rate of change of the original frequency and the rate of change of the original frequency is less than zero, that is, At this time, the grid frequency is generally unstable. The formula for calculating the power adjustment ΔP can be:

[0079]

[0080] Where m2 is a constant, is the rate of change of the original frequency, is the quadratic change rate of the original frequency, Δf is the frequency change of the original frequency, f N is the rated frequency of the power grid, T j is the inertia time constant, the rated active power P of the converter, i.e. the energy storage battery pack N is the rated active power of the converter. The power adjustment ΔP of the inertia response increases exponentially with (1+|Δf|), and the power adjustment ΔP is positively correlated with Δf, (1+|Δf|) m2 Used to suppress frequency deviation.

[0081] After the power adjustment ΔP is calculated, the power adjustment ΔP and the rated frequency modulation power P of the power grid can be used to calculate the power adjustment ΔP. EMS To calculate the actual frequency modulation power P of the power grid ref , the specific formula is:

[0082] P ref =P EMS +ΔP;

[0083] Among them, P ref is the actual frequency regulation power of the power grid, P EMS is the rated frequency modulation power P of the power grid EMS , ΔP is the power adjustment amount. Since the change rate of the original frequency of the power grid is taken into account when adjusting the power grid frequency, the adjustment of the power grid frequency can be achieved more accurately, thereby improving the accuracy of the power grid frequency adjustment and further improving the stability of the power grid.

[0084] S104: Adjust the frequency of the power grid according to the actual frequency modulation power.

[0085] In this embodiment, after calculating the actual frequency modulation power of the power grid, the frequency of the power grid can be adjusted according to the actual frequency modulation power. Since the speed of change of the change rate of the original frequency of the power grid is taken into account when adjusting the power grid frequency, the adjustment of the power grid frequency can be achieved more accurately, thereby improving the accuracy of the power grid frequency adjustment and further improving the stability of the power grid.

[0086] Specifically, when the actual frequency modulation power P ref >0 controls the energy storage battery pack to discharge. ref >K2*P Bat_N , the power set by EMS is greater than the power limit of battery discharge, and the power given by PCS controller, that is, the actual frequency modulation power, is executed according to the limited power of the battery, that is, P ref =K2*P Bat_N (P Bat_Nis the rated power value of the battery); when P ref <K2*P Bat_N , the power set by EMS is not greater than the power limit of the battery, and the power given by the PCS controller is also the actual frequency modulation power P ref =P EMS +ΔP. When the actual FM power P ref <0 controls the energy storage battery pack to discharge, when P ref <-K1*P Bat_N , the power set by EMS is greater than the power limit of battery charging, and the power given by PCS controller, that is, the actual frequency modulation power, is executed according to the limited power of the battery, that is, P ref =-K1*P Bat_N When P ref >-K1*P Bat_N , the power set by EMS is not greater than the power limit of the battery, and the power given by the PCS controller is also the actual frequency modulation power P ref =P EMS +ΔP.

[0087] In one possible implementation, after the frequency of the power grid is adjusted according to the actual frequency modulation power, the adjusted frequency of the power grid can also be obtained; if the adjusted frequency of the power grid meets the exit condition of the inertia response mode, the adjustment step is determined according to the actual frequency modulation power; the actual frequency modulation power is adjusted according to the adjustment step to obtain the target frequency modulation power; the frequency of the power grid is adjusted according to the target frequency modulation power; and the step of adjusting the actual frequency modulation power according to the adjustment step to obtain the target frequency modulation power is returned to execute until the target frequency modulation power is equal to the rated frequency modulation power of the power grid.

[0088] It can be understood that after adjusting the frequency of the power grid according to the actual frequency modulation power, it can be determined whether the power grid frequency has reached the exit condition of the inertia response mode at this time, that is, whether the fluctuation of the power grid frequency has been reduced to a normal state at this time, and whether it is necessary to switch the control mode of the power grid from the inertia response mode to the normal control mode, that is, the EMS control mode. Therefore, the adjusted frequency of the power grid after the actual frequency modulation power adjustment can be obtained first, and then the change rate of the adjusted frequency and the frequency change of the adjusted frequency can be calculated according to the adjusted frequency of the power grid. If the product of the frequency change of the adjusted frequency and the change rate of the adjusted frequency is less than zero, and the absolute value of the frequency change of the adjusted frequency is less than the inertia response critical value, it can be determined whether the power grid frequency has reached the exit condition of the inertia response mode at this time. Then at this time, the PCS controller can perform the inertia response to exit the soft switching mode, that is, the adjustment step length P can be determined first. T , the actual frequency modulation power P at this time ref =P EMS+ΔP', ΔP' is the power adjustment when the grid frequency meets the exit condition of inertia response mode. When ΔP'>0, ΔP' is adjusted by step size P T Reduce to obtain the target frequency modulation power and gradually adjust the frequency of the power grid based on the target frequency modulation power until ΔP'=0, at which time P ref =P EMS , when ΔP'<0, ΔP' is adjusted by step size P T Increase to obtain the target frequency modulation power and gradually adjust the frequency of the power grid based on the target frequency modulation power until ΔP'=0, at which time P ref =P EMS , thereby realizing soft switching from inertia response mode to EMS control mode, avoiding the hard switching from inertia response mode to EMS control mode, which may cause power mutation and thus change the grid frequency, and ultimately cause secondary fluctuation hazards of the grid frequency, thereby improving the accuracy of grid frequency adjustment and thus improving the stability of the grid.

[0089] It can be seen from this that an embodiment of the present application provides a method for adjusting the frequency of a power grid. When the control mode of the power grid is the inertia response mode, the actual frequency modulation power is calculated according to the secondary change rate of the original frequency of the power grid, and the frequency of the power grid is adjusted according to the actual frequency modulation power. That is, when the power grid frequency is adjusted, the speed of change of the change rate of the original frequency of the power grid is taken into account, and the adjustment of the power grid frequency can be achieved more accurately, thereby improving the accuracy of the power grid frequency adjustment and further improving the stability of the power grid.

[0090] See also Figure 6 The present application also provides a power grid frequency adjustment device, the device comprising:

[0091] An acquisition unit 601 is used to acquire the original frequency of the power grid;

[0092] A determining unit 602, configured to determine a control mode of a power grid according to the original frequency;

[0093] a calculation unit 603, configured to calculate, if the control mode of the power grid is an inertia response mode, actual frequency modulation power of the power grid according to the original frequency, wherein the actual frequency modulation power is determined according to a quadratic change rate of the original frequency, and the quadratic change rate of the original frequency is used to indicate a change speed of a change rate of the original frequency;

[0094] The frequency modulation unit 604 is used to adjust the frequency of the power grid according to the actual frequency modulation power.

[0095] Optionally, the calculation unit 603 is used to calculate the change rate of the original frequency and the frequency change amount of the original frequency according to the original frequency;

[0096] Calculating the secondary change rate of the original frequency according to the change rate of the original frequency;

[0097] Obtaining the rated frequency modulation power of the power grid, the rated frequency of the power grid, the inertia time constant and the rated active power of the converter;

[0098] The actual frequency modulation power of the power grid is calculated according to the change rate of the original frequency, the secondary change rate of the original frequency, the frequency change of the original frequency, the rated frequency modulation power of the power grid, the rated frequency of the power grid, the inertia time constant and the rated active power of the converter.

[0099] Optionally, the calculation unit 603 is specifically configured to:

[0100] If the product of the quadratic change rate of the original frequency and the change rate of the original frequency is greater than zero, the power adjustment amount is calculated according to the change rate of the original frequency, the quadratic change rate of the original frequency, the frequency change amount of the original frequency, the inertia time constant and the rated active power of the converter;

[0101] If the product of the quadratic change rate of the original frequency and the change rate of the original frequency is less than zero, the power adjustment amount is calculated according to the change rate of the original frequency, the frequency change of the original frequency, the inertia time constant and the rated active power of the converter;

[0102] The actual frequency regulation power of the power grid is obtained by calculation according to the power adjustment amount and the rated frequency regulation power of the power grid.

[0103] Optionally, the determining unit 602 is specifically configured to:

[0104] Calculating the frequency change of the original frequency and the change rate of the original frequency according to the original frequency of the power grid;

[0105] If the product of the frequency change of the original frequency and the change rate of the original frequency is greater than zero, and the absolute value of the frequency change of the original frequency is greater than the inertia response critical value, then determining that the control mode of the power grid is the inertia response mode;

[0106] If the product of the frequency change of the original frequency and the change rate of the original frequency is greater than zero, and the absolute value of the frequency change of the original frequency is greater than the inertia response critical value, the control mode of the power grid is determined to be the normal control mode.

[0107] Optionally, the device further comprises:

[0108] The acquisition unit 601 is further configured to acquire the adjusted frequency of the power grid;

[0109] The determining unit 602 is further configured to determine an adjustment step size according to the actual frequency modulation power if the adjustment frequency of the power grid meets the exit condition of the inertia response mode;

[0110] An adjustment unit, configured to adjust the actual frequency modulation power according to the adjustment step size to obtain a target frequency modulation power;

[0111] The frequency modulation unit 604 is further configured to adjust the frequency of the power grid according to the target frequency modulation power;

[0112] A return unit is used to return to the step of adjusting the actual frequency regulation power according to the adjustment step to obtain the target frequency regulation power until the target frequency regulation power is equal to the rated frequency regulation power of the power grid.

[0113] The embodiment of the present application also provides a computer device, including: a memory, a processor, and a bus system;

[0114] Wherein, the memory is used to store programs;

[0115] The processor is used to execute the program in the memory to implement any one of the above-mentioned power grid frequency adjustment methods;

[0116] The bus system is used to connect the memory and the processor so that the memory and the processor can communicate with each other.

[0117] An embodiment of the present application also provides a computer-readable storage medium storing instructions, which, when executed on a computer, enables the computer to execute any one of the power grid frequency adjustment methods described above.

[0118] Finally, it should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0119] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for adjusting power grid frequency, characterized in that: The method comprises: Get the original frequency of the power grid; determining a control mode of the power grid according to the original frequency; If the control mode of the power grid is the inertia response mode, the actual frequency modulation power of the power grid is calculated according to the original frequency, and the actual frequency modulation power is determined according to the quadratic change rate of the original frequency, and the quadratic change rate of the original frequency is used to indicate the change speed of the change rate of the original frequency; Adjusting the frequency of the power grid according to the actual frequency modulation power; Wherein, determining the control mode of the power grid according to the original frequency includes: Calculating the frequency change of the original frequency and the change rate of the original frequency according to the original frequency of the power grid; If the product of the frequency change of the original frequency and the change rate of the original frequency is greater than zero, and the absolute value of the frequency change of the original frequency is greater than the inertia response critical value, then determining that the control mode of the power grid is the inertia response mode; If the product of the frequency change of the original frequency and the change rate of the original frequency is greater than zero, and the absolute value of the frequency change of the original frequency is greater than the inertia response critical value, then the control mode of the power grid is determined to be the normal control mode; The step of calculating the actual frequency modulation power of the power grid according to the original frequency includes: Calculate the rate of change of the original frequency and the frequency change amount of the original frequency according to the original frequency; Calculating the secondary change rate of the original frequency according to the change rate of the original frequency; Obtaining the rated frequency modulation power of the power grid, the rated frequency of the power grid, the inertia time constant and the rated active power of the converter; The actual frequency modulation power of the power grid is calculated according to the change rate of the original frequency, the secondary change rate of the original frequency, the frequency change of the original frequency, the rated frequency modulation power of the power grid, the rated frequency of the power grid, the inertia time constant and the rated active power of the converter; The step of calculating the actual frequency modulation power of the power grid according to the rate of change of the original frequency, the secondary rate of change of the original frequency, the frequency change of the original frequency, the rated frequency modulation power of the power grid, the rated frequency of the power grid, the inertia time constant and the rated active power of the converter includes: If the product of the quadratic change rate of the original frequency and the change rate of the original frequency is greater than zero, the power adjustment amount is calculated according to the change rate of the original frequency, the quadratic change rate of the original frequency, the frequency change amount of the original frequency, the inertia time constant and the rated active power of the converter; If the product of the quadratic change rate of the original frequency and the change rate of the original frequency is less than zero, the power adjustment amount is calculated according to the change rate of the original frequency, the frequency change of the original frequency, the inertia time constant and the rated active power of the converter; The actual frequency modulation power of the power grid is obtained by calculation according to the power adjustment amount and the rated frequency modulation power of the power grid; The power adjustment amount is calculated according to the change rate of the original frequency, the secondary change rate of the original frequency, the frequency change of the original frequency, the inertia time constant and the rated active power of the converter, specifically including: Among them, m1 and m2 are constants. is the rate of change of the original frequency, is the quadratic change rate of the original frequency, Δf is the frequency change of the original frequency, f N is the rated frequency of the power grid, T j is the inertia time constant, P N is the rated active power of the converter; The power adjustment amount is calculated according to the change rate of the original frequency, the frequency change of the original frequency, the inertia time constant and the rated active power of the converter, specifically including: Where m2 is a constant, is the rate of change of the original frequency, Δf is the frequency change of the original frequency, f N is the rated frequency of the power grid, T j is the inertia time constant, P N is the rated active power of the converter.

2. The method according to claim 1, characterized in that: After adjusting the frequency of the power grid according to the actual frequency modulation power, the method further includes: Obtaining an adjusted frequency of the power grid; If the adjustment frequency of the power grid meets the exit condition of the inertia response mode, determining the adjustment step size according to the actual frequency modulation power; Adjust the actual frequency modulation power according to the adjustment step to obtain a target frequency modulation power; Adjusting the frequency of the power grid according to the target frequency modulation power; Return to the step of adjusting the actual frequency modulation power according to the adjustment step to obtain the target frequency modulation power, until the target frequency modulation power is equal to the rated frequency modulation power of the power grid.

3. A power grid frequency adjustment device, characterized in that: The device comprises: An acquisition unit, used for acquiring the original frequency of the power grid; a determining unit, configured to determine a control mode of a power grid according to the original frequency; a calculation unit, configured to calculate, if the control mode of the power grid is an inertia response mode, actual frequency modulation power of the power grid according to the original frequency, wherein the actual frequency modulation power is determined according to a quadratic change rate of the original frequency, wherein the quadratic change rate of the original frequency is used to indicate a change speed of a change rate of the original frequency; A frequency modulation unit, used for adjusting the frequency of the power grid according to the actual frequency modulation power; Wherein, the determining unit is specifically used for: Calculating the frequency change of the original frequency and the change rate of the original frequency according to the original frequency of the power grid; If the product of the frequency change of the original frequency and the change rate of the original frequency is greater than zero, and the absolute value of the frequency change of the original frequency is greater than the inertia response critical value, then determining that the control mode of the power grid is the inertia response mode; If the product of the frequency change of the original frequency and the change rate of the original frequency is greater than zero, and the absolute value of the frequency change of the original frequency is greater than the inertia response critical value, then the control mode of the power grid is determined to be the normal control mode; The computing unit is specifically used for: Calculate the rate of change of the original frequency and the frequency change amount of the original frequency according to the original frequency; Calculating the secondary change rate of the original frequency according to the change rate of the original frequency; Obtaining the rated frequency modulation power of the power grid, the rated frequency of the power grid, the inertia time constant and the rated active power of the converter; The actual frequency modulation power of the power grid is calculated according to the change rate of the original frequency, the secondary change rate of the original frequency, the frequency change of the original frequency, the rated frequency modulation power of the power grid, the rated frequency of the power grid, the inertia time constant and the rated active power of the converter; The computing unit is specifically used for: If the product of the quadratic change rate of the original frequency and the change rate of the original frequency is greater than zero, the power adjustment amount is calculated according to the change rate of the original frequency, the quadratic change rate of the original frequency, the frequency change amount of the original frequency, the inertia time constant and the rated active power of the converter; If the product of the quadratic change rate of the original frequency and the change rate of the original frequency is less than zero, the power adjustment amount is calculated according to the change rate of the original frequency, the frequency change of the original frequency, the inertia time constant and the rated active power of the converter; The actual frequency modulation power of the power grid is obtained by calculation according to the power adjustment amount and the rated frequency modulation power of the power grid; The computing unit is specifically used for: Among them, m1 and m2 are constants. is the rate of change of the original frequency, is the quadratic change rate of the original frequency, Δf is the frequency change of the original frequency, f N is the rated frequency of the power grid, T j is the inertia time constant, P N is the rated active power of the converter; The computing unit is specifically used for: Where m2 is a constant, is the rate of change of the original frequency, Δf is the frequency change of the original frequency, f N is the rated frequency of the power grid, T j is the inertia time constant, P N is the rated active power of the converter.

4. A computer device, characterized in that: include: Memory, processor, and bus system; Wherein, the memory is used to store programs; The processor is used to execute the program in the memory to implement the method according to any one of claims 1 to 2; The bus system is used to connect the memory and the processor so that the memory and the processor can communicate with each other.

5. A computer-readable storage medium, characterized in that: The device stores instructions which, when executed on a computer, cause the computer to execute the method according to any one of claims 1 to 2.

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