A stepwise regression frequency control method and system

Abstract

The application discloses a kind of stepwise regression primary frequency control method and system, the method includes: obtaining primary frequency power theoretical value, and setting regression coefficient;Record the maximum frequency modulation component when the process of primary frequency action;When frequency is in low frequency stage, again primary frequency is from the maximum frequency modulation component regression stage, with k*△Q as regression step, satisfy (1-n*k)*△Q≤△N<(1-(n-1)*k)*△Q, then actual unit real-time primary frequency component is (1-(n-1)*k)*△Q;When frequency is in high frequency stage, again primary frequency is from the maximum frequency modulation component regression stage, with k*△Q regression step, satisfy (1-n*k)*△Q≥△N>(1-(n-1)*k)*△Q, then actual unit real-time primary frequency component is (1-(n-1)*k)*△Q;Wherein,△N indicates primary frequency power theoretical value, k indicates regression coefficient;△Q indicates maximum frequency modulation component;N indicates the number of steps of stepwise regression. By the stepwise regression primary frequency control method and system disclosed in the application, the stability of primary frequency adjustment can be improved.

Description

Technical Field

[0001] This invention relates to the field of primary frequency modulation technology, specifically to a cascade regression primary frequency modulation control method and system. Background Technology

[0002] Grid frequency is a measure of the balance between power generation and electricity load. When the grid frequency deviates from its rated value, generating units in the grid adjust their active power to limit frequency fluctuations. Currently, my country's grid frequency adjustment mainly relies on coal-fired power units and other thermal power generating units rapidly changing their output to ensure timely grid frequency stability.

[0003] Currently, most thermal power units operate under Automatic Gain Control (AGC) mode, where load regulation targets are received from grid dispatch instructions. This results in significant randomness in unit load regulation, which cannot be accurately predicted through effective means. Analysis of the primary frequency regulation actions and assessment results of thermal power units reveals that even if experimental primary frequency regulation test results meet industry regulations, the timing and amplitude of primary frequency regulation actions remain uncertain during frequent load adjustments under AGC mode. Existing primary frequency regulation control is based on frequency difference proportional regulation. With rapid changes in grid frequency or variations in the response capabilities of the unit's frequency measurement devices, large and rapid fluctuations can easily occur during frequency regulation, which is detrimental to grid stability and also restricts the unit's primary frequency regulation performance.

[0004] Existing technology, specifically invention patent CN110311389A, describes a method and system for joint frequency regulation and peak shaving of cascade hydropower plants suitable for renewable energy consumption. The method includes converting the grid frequency deviation into ACE (Active Frequency Control), obtaining the required total regulation, allocating the total regulation based on the regulation margin of each unit in the cascade hydropower plant, and distributing the allocated regulation to each unit. However, this existing technology allocates the regulation based on the regulation margin of each unit, improving the flexibility of hydropower operation and avoiding unstable operating conditions of the hydropower units. Summary of the Invention

[0005] The technical problem to be solved by this invention is to address the issue of grid instability and the limitation of primary frequency regulation performance of generating units caused by primary frequency regulation based on frequency difference ratio.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0007] A step-regression primary frequency modulation control method includes the following steps:

[0008] Obtain the theoretical value of primary frequency modulation power and set the regression coefficient;

[0009] Record the frequency modulation components during a single frequency modulation operation, and obtain the maximum frequency modulation component during that single frequency modulation operation.

[0010] When the frequency is in the low frequency stage, the frequency is adjusted again from the maximum frequency adjustment component return stage, with k*△Q as the return step size, satisfying (1-n*k)*△Q≤△N<(1-(n-1)*k)*△Q, then the actual unit real-time primary frequency adjustment component is (1-(n-1)*k)*△Q.

[0011] When the frequency is in the high-frequency stage, the frequency is adjusted again from the maximum frequency adjustment component return stage, with a return step of k*△Q, satisfying (1-n*k)*△Q≥△N>(1-(n-1)*k)*△Q, then the actual unit real-time primary frequency adjustment component is (1-(n-1)*k)*△Q.

[0012] Where △N represents the theoretical value of primary frequency modulation power, k represents the regression coefficient, △Q represents the maximum frequency modulation component, and n represents the number of stages in the ladder.

[0013] In one embodiment of the present invention, during the frequency modulation operation recovery phase, a step threshold is set, and when the frequency recovers to 0 according to the set step threshold, the fluctuation frequency during the frequency modulation process can be reduced.

[0014] In one embodiment of the present invention, the step threshold is obtained by the following formula:

[0015] T = △Q / n;

[0016] Where T represents the step threshold.

[0017] In one embodiment of the present invention, the regression coefficient is an empirical value that is dynamically adjusted manually.

[0018] In one embodiment of the present invention, when the frequency is low, the maximum frequency modulation component is positive; when the frequency is high, the maximum frequency modulation component is negative.

[0019] This invention also provides a system for a cascaded regression primary frequency modulation control method, comprising:

[0020] The theoretical value and regression coefficient module is used to obtain the theoretical value of primary frequency modulation power and set the regression coefficient;

[0021] The maximum frequency modulation component module records the frequency modulation components during a single frequency modulation operation and obtains the maximum frequency modulation component during the current single frequency modulation operation.

[0022] The low-frequency primary frequency modulation component module is used to perform a secondary frequency modulation from the maximum frequency modulation component back to the stage when the frequency is in the low-frequency stage, with k*△Q as the regression step size, satisfying (1-n*k)*△Q≤△N<(1-(n-1)*k)*△Q, then the actual real-time primary frequency modulation component of the unit is (1-(n-1)*k)*△Q;

[0023] The high-frequency primary frequency modulation component module is used to perform a secondary frequency modulation from the maximum frequency modulation component back to the stage when the frequency is in the high-frequency stage, with a return step size of k*△Q, satisfying (1-n*k)*△Q≥△N>(1-(n-1)*k)*△Q, then the actual real-time primary frequency modulation component of the unit is (1-(n-1)*k)*△Q.

[0024] Where △N represents the theoretical value of primary frequency modulation power, k represents the regression coefficient, △Q represents the maximum frequency modulation component, and n represents the number of stages in the ladder.

[0025] In one embodiment of the present invention, the system further includes a stepped threshold module, which is used to set a stepped threshold during the return phase of a frequency modulation action. When the system recovers to 0 according to the stepped threshold, the frequency fluctuation during the frequency modulation process can be reduced.

[0026] In one embodiment of the present invention, the step threshold is obtained by the following formula:

[0027] T = △Q / n;

[0028] Where T represents the step threshold.

[0029] In one embodiment of the present invention, the regression coefficient is an empirical value that is dynamically adjusted manually.

[0030] In one embodiment of the present invention, when the frequency is low, the maximum frequency modulation component is positive; when the frequency is high, the maximum frequency modulation component is negative.

[0031] Compared with existing technologies, the beneficial effects of this invention are: by returning the primary frequency modulation component in a stepped manner, the value of the frequency modulation component during the primary frequency modulation process is increased, thereby enhancing the unit's contribution to primary frequency modulation adjustment. This significantly reduces unnecessary disturbances in the primary frequency modulation adjustment process caused by fluctuations in speed or frequency measurements, and improves the stability of the unit's participation in primary frequency modulation adjustment. Furthermore, by setting a stepped threshold, the fluctuation frequency during frequency modulation can be adjusted, reducing the fluctuation frequency during frequency modulation and improving the overall response capability. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the theoretical value curve of the primary frequency modulation power of the present invention.

[0033] Figure 2This is a flowchart of a step-regression primary frequency modulation control method according to the present invention.

[0034] Figure 3 This is a flowchart of the low-frequency stage step-regression primary frequency modulation control method of the present invention.

[0035] Figure 4 This is a flowchart of the high-frequency stage step-regression primary frequency modulation control method of the present invention.

[0036] Figure 5 This is a system block diagram of a step-regression primary frequency modulation control method according to the present invention. Detailed Implementation

[0037] To facilitate understanding of the technical solution of the present invention by those skilled in the art, the technical solution of the present invention will now be further described in conjunction with the accompanying drawings.

[0038] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0039] Please see Figure 1 As shown, the theoretical value of the primary frequency regulation power ΔN is calculated based on the speed deviation Δr and the corresponding unit speed unequal rate, where the unit speed unequal rate is a fixed value. That is, ΔN is the real-time primary frequency regulation component calculated based on the speed deviation Δr and the corresponding unit speed unequal rate. Therefore, under a fixed speed deviation, the theoretical value of the primary frequency regulation power is fixed. Regardless of the unit's operating condition, the calculated primary frequency regulation power under the same speed deviation is a fixed value corresponding to the speed deviation. However, in dynamic processes, the speed deviation often fluctuates frequently due to measurement factors, leading to instability in the primary frequency regulation process and affecting the unit's contribution to primary frequency regulation.

[0040] Please see Figure 2 As shown, the present invention provides a cascaded regression primary frequency modulation control method, comprising the following steps:

[0041] S100 obtains the theoretical value of primary frequency modulation power and sets the regression coefficient.

[0042] The theoretical value of primary frequency regulation power is calculated based on the speed deviation and the speed unequal rate of the corresponding unit level. The regression coefficient is an empirical value, which is dynamically adjusted manually. Specifically, it needs to be dynamically adjusted manually based on the specific engineering adjustment effect.

[0043] S200 records the frequency modulation components during a single frequency modulation operation and obtains the maximum frequency modulation component during the current single frequency modulation operation.

[0044] Specifically, when the frequency is low, the maximum frequency modulation (FM) component is positive; when the frequency is high, the maximum FM component is negative. Using 50 Hz as a standard, frequencies above 50 Hz are considered high-frequency and require a single FM modulation to be downgraded to the 50 Hz standard. Therefore, at high frequencies, the maximum FM component needs to be negative. Similarly, frequencies below 50 Hz are considered low-frequency and require a single FM modulation to be upgraded to the 50 Hz standard. Therefore, at low frequencies, the maximum FM component needs to be positive for compensation.

[0045] S300, when the frequency is in the low frequency stage, the frequency is adjusted again from the maximum frequency adjustment component return stage, with k*△Q as the return step size, satisfying (1-n*k)*△Q≤△N<(1-(n-1)*k)*△Q, then the actual unit real-time primary frequency adjustment component is (1-(n-1)*k)*△Q.

[0046] S400, when the frequency is in the high-frequency stage, the frequency is adjusted again from the maximum frequency adjustment component return stage, with a return step of k*△Q, satisfying (1-n*k)*△Q≥△N>(1-(n-1)*k)*△Q, then the actual unit real-time primary frequency adjustment component is (1-(n-1)*k)*△Q.

[0047] Where △N represents the theoretical value of primary frequency modulation power, k represents the regression coefficient, △Q represents the maximum frequency modulation component, and n represents the number of stages in the ladder.

[0048] Please see Figures 2 to 4 As shown, in one embodiment of the present invention, during the frequency modulation recovery phase, a stepped threshold is set. When the frequency recovers to 0 according to the set stepped threshold, the fluctuation frequency during frequency modulation can be reduced. The stepped threshold is obtained by the following formula:

[0049] T = △Q / n;

[0050] Where T represents the step threshold.

[0051] By regressing the primary frequency regulation component in a stepped manner, the value of the frequency regulation component during the primary frequency regulation process is increased, thereby enhancing the unit's contribution to the primary frequency regulation adjustment. On the other hand, it greatly reduces unnecessary disturbances in the primary frequency regulation process caused by fluctuations in speed or frequency measurements, thus improving the stability of the unit's participation in the primary frequency regulation adjustment.

[0052] Please see Figure 5As shown, the present invention also provides a system for a step-regression primary frequency modulation control method, including a theoretical value and regression coefficient module 100, a maximum frequency modulation component module 200, a low-frequency primary frequency modulation component module 300, a high-frequency primary frequency modulation component module 400, and a step threshold module 500. The theoretical value and regression coefficient module 100 is used to obtain the theoretical value of the primary frequency modulation power and set the regression coefficients. The maximum frequency modulation component module 200 is used to record the frequency modulation components during the primary frequency modulation operation and obtain the maximum frequency modulation component during the current primary frequency modulation operation. The low-frequency primary frequency modulation component module 300 is used to, when the frequency is in the low-frequency stage, perform a secondary frequency modulation from the maximum frequency modulation component regression stage, with k*ΔQ as the regression step size, satisfying (1-n*k)*ΔQ≤ΔN< The actual real-time primary frequency modulation component of the unit is (1-(n-1)*k)*△Q. The high-frequency primary frequency modulation component module 400 is used to, when the frequency is in the high-frequency stage, perform a primary frequency modulation from the maximum frequency modulation component regression stage, with a regression step size of k*△Q, satisfying (1-n*k)*△Q≥△N>(1-(n-1)*k)*△Q. Here, △N represents the theoretical value of the primary frequency modulation power, k represents the regression coefficient, △Q represents the maximum frequency modulation component, and n represents the number of stages. The step threshold module 500 is used to set a step threshold during the primary frequency modulation action regression stage. When the step threshold recovers to 0, the fluctuation frequency during frequency modulation can be reduced. The step threshold is obtained through the following formula:

[0053] T = △Q / n;

[0054] Where T represents the step threshold.

[0055] Please see Figure 5 As shown, in one embodiment of the present invention, the regression coefficient is an empirical value, which is dynamically adjusted manually. When the frequency is low, the maximum frequency modulation component is positive; when the frequency is high, the maximum frequency modulation component is negative.

[0056] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention, and no reference numerals in the claims should be construed as limiting the scope of the claims.

[0057] The above embodiments are merely examples of implementation methods of the invention. The scope of protection of the present invention is not limited to the above embodiments. For those skilled in the art, several modifications and improvements can be made without departing from the concept of the present invention, and these all fall within the scope of protection of the present invention.

Claims

1. A step-regression primary frequency modulation control method, characterized in that, Includes the following steps: Obtain the theoretical value of primary frequency modulation power and set the regression coefficient; Record the frequency modulation components during a single frequency modulation operation, and obtain the maximum frequency modulation component during that single frequency modulation operation. When the frequency is in the low frequency stage, the frequency is adjusted again from the maximum frequency adjustment component return stage, with k*△Q as the return step size, satisfying (1-n*k)*△Q≤△N<(1-(n-1)*k)*△Q, then the actual unit real-time primary frequency adjustment component is (1-(n-1)*k)*△Q. When the frequency is in the high-frequency stage, the frequency is adjusted again from the maximum frequency adjustment component return stage, with a return step of k*△Q, satisfying (1-n*k)*△Q≥△N>(1-(n-1)*k)*△Q, then the actual unit real-time primary frequency adjustment component is (1-(n-1)*k)*△Q. Where △N represents the theoretical value of primary frequency modulation power, k represents the regression coefficient, △Q represents the maximum frequency modulation component, and n represents the number of stages in the ladder.

2. The cascade regression primary frequency modulation control method according to claim 1, characterized in that, During the frequency modulation recovery phase, a stepped threshold is set. When the frequency returns to 0 according to the set stepped threshold, the frequency fluctuation during the frequency modulation process can be reduced.

3. The cascade regression primary frequency modulation control method according to claim 2, characterized in that, The stepped threshold is obtained using the following formula: T = △Q / n; Where T represents the step threshold.

4. The cascade regression primary frequency modulation control method according to claim 1, characterized in that, The regression coefficients are empirical values ​​that are dynamically adjusted manually.

5. The cascade regression primary frequency modulation control method according to claim 1, characterized in that, When the frequency is low, the maximum frequency modulation component is positive; when the frequency is high, the maximum frequency modulation component is negative.

6. A system based on any one of the stepwise regression primary frequency modulation control methods described in 1-5, characterized in that, include: The theoretical value and regression coefficient module is used to obtain the theoretical value of primary frequency modulation power and set the regression coefficient; The maximum frequency modulation component module records the frequency modulation components during a single frequency modulation operation and obtains the maximum frequency modulation component during the current single frequency modulation operation. The low-frequency primary frequency modulation component module is used to perform a secondary frequency modulation from the maximum frequency modulation component back to the stage when the frequency is in the low-frequency stage, with k*△Q as the regression step size, satisfying (1-n*k)*△Q≤△N<(1-(n-1)*k)*△Q, then the actual real-time primary frequency modulation component of the unit is (1-(n-1)*k)*△Q; The high-frequency primary frequency modulation component module is used to perform a secondary frequency modulation from the maximum frequency modulation component back to the stage when the frequency is in the high-frequency stage, with a return step size of k*△Q, satisfying (1-n*k)*△Q≥△N>(1-(n-1)*k)*△Q, then the actual real-time primary frequency modulation component of the unit is (1-(n-1)*k)*△Q. Where △N represents the theoretical value of primary frequency modulation power, k represents the regression coefficient, △Q represents the maximum frequency modulation component, and n represents the number of stages in the ladder.

7. The system of the cascade regression primary frequency modulation control method according to claim 6, characterized in that, The system also includes a stepped threshold module, which is used to set a stepped threshold during the return phase of a frequency modulation action. When the system recovers to 0 based on the stepped threshold, the frequency fluctuation during the frequency modulation process can be reduced.

8. The system of the cascade regression primary frequency modulation control method according to claim 7, characterized in that, The stepped threshold is obtained using the following formula: T = △Q / n; Where T represents the step threshold.

9. The system of the cascade regression primary frequency modulation control method according to claim 6, characterized in that, The regression coefficients are empirical values ​​that are dynamically adjusted manually.

10. The system of the cascade regression primary frequency modulation control method according to claim 6, characterized in that, When the frequency is low, the maximum frequency modulation component is positive; when the frequency is high, the maximum frequency modulation component is negative.

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