A switching control method for high standby operation mode of primary frequency modulation of coal-fired unit

Abstract

The application discloses a switching control method for primary frequency modulation high standby operation mode of a coal-fired unit, which comprises the following steps: designing the primary frequency modulation high standby operation mode and obtaining parameters; judging the switching logic between the primary frequency modulation high standby operation mode and the economic operation mode; and switching the control method between the primary frequency modulation high standby operation mode and the economic operation mode. The application adds a set of control logic for the primary frequency modulation high standby operation mode on the basis of the original logic of the coal-fired unit, and adds the judging logic and the control logic for switching between the economic operation mode and the primary frequency modulation high standby operation mode. The application enables the coal-fired unit to operate in the mode of mainly maintaining the economic operation under the condition that the power system is relatively safe, and enables the coal-fired unit to select the primary frequency modulation high standby mode under the condition that the primary frequency modulation capacity of the power system is small, so that the partial operation economy of the unit is sacrificed to provide high-capacity standby for the frequency stability of the power system, and the problem that the operation economy and the frequency modulation capacity of the unit are difficult to be considered together is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to a primary frequency modulation optimization control method of a coal-fired unit, in particular to a high standby operation mode and switching control method of a primary frequency modulation of a coal-fired unit. BACKGROUND

[0002] The existing design method of the sliding pressure curve of the coal-fired unit is: considering the economic operation as the main factor, and designing according to the minimum standard of the primary frequency modulation regulation capacity to meet the grid evaluation. This kind of operation mode mainly considers the economy of the unit, which is called the economic operation mode in the present application. The present application proposes an operation mode in which the unit can provide high-capacity primary frequency modulation standby, and the unit can sacrifice part of the economy to provide high-capacity primary frequency modulation standby for the power system, which can maximize the stability of the power system frequency. This kind of operation mode is called the primary frequency modulation high standby operation mode in the present application. The switching control method of the primary frequency modulation high standby operation mode of the coal-fired unit proposed in the present application adds a set of high standby operation logic in the unit, forms two operation modes for selection, and then realizes the switching control between the economic operation mode and the primary frequency modulation high standby mode, solving the problem that the unit cannot balance the operation economy and the primary frequency modulation adjustable capacity.

[0003] The comparison of the existing invention and reference is as follows:

[0004] A primary frequency modulation control method for a full-load coal-fired unit CN2020101217868 adopts a closed-loop control method, dynamically and real-time corrects the main steam pressure set value according to the grid frequency deviation, effectively avoids the anti-regulation of the primary frequency modulation under the turbine following mode, ensures the rapidity and accuracy of the primary frequency modulation performance of the unit under this mode, and corrects the sliding pressure curve according to the primary frequency modulation control performance.

[0005] A primary frequency modulation optimization control method based on the heat storage of the thermal system of the coal-fired unit CN2019101890431 measures and records the temperature and pressure of the working medium and the metal wall surface of each part of the thermal system of the coal-fired unit in real time, and then converts the heat storage amount of the thermal system, so as to efficiently and accurately participate in the primary frequency modulation control and maintain the rapid stability of the grid frequency.

[0006] A primary frequency modulation time period control system and method for a coal-fired power generating unit CN202111271283X proposes a new primary frequency modulation time period control method, which can not only quickly affect the grid frequency requirement, but also ensure the integral contribution of the primary frequency modulation, and can stably and smoothly adjust the high-pressure regulating valve under large disturbance primary frequency modulation, which can effectively prevent the high-frequency swing of the high-pressure regulating valve GV3 and GV4.

[0007] A control system and method for improving the primary frequency regulation performance index of a thermal power unit CN202210603152 5, comprising a steam turbine speed or grid frequency signal acquisition device F1, which sends the collected signals to the primary frequency regulation optimization control system after signal processing; at the same time, the increased high-precision grid frequency synchronous acquisition device sends the collected grid frequency synchronous signals (synchronous with PMU) to the primary frequency regulation optimization control system, and the primary frequency regulation optimization control system sends the processed primary frequency regulation load instruction to the steam turbine main control system, and the output of the steam turbine main control system is sent to the steam turbine control system, and at the same time the steam turbine control system also receives the primary frequency regulation gate command output by the primary frequency regulation optimization control system to jointly control the steam turbine gate action.

[0008] Zeng Jiangzhuo, Sun Zhe, Pan Yang. Optimization of throttle pressure operation curve of throttle pressure regulating turbine unit based on primary frequency modulation capacity [J]. Hubei Electric Power, 2016, 40(06): 37-41. Taking throttle pressure regulating turbine unit as the research object and taking its primary frequency modulation capacity and coal consumption of thermal power unit as the target conditions, the quantitative relationship between different throttle pressure curve setting values and the primary frequency modulation capacity of the unit is compared, and the setting principle of the throttle pressure curve of this type of turbine unit is proposed.

[0009] Li Bingtian, Liang Zhuo, Du Xinjiang, Yang Xuhui, Yang Sen. Research on throttle pressure curve of throttle pressure regulating turbine unit based on primary frequency modulation capacity [J]. Henan Electric Power, 2022(S2): 10-14. In this paper, the high gate flow characteristics of throttle pressure regulating turbine are calculated based on historical operation data, and the sliding pressure operation test is carried out. The relationship between high gate opening and turbine heat consumption rate is obtained through comparison test under different typical loads.

[0010] Yu Jinshu. Comprehensive optimization strategy of turbine operation mode under large flow extraction condition [J]. Thermal Power Engineering, 2017, 32(06): 123-128+138. A comprehensive optimization strategy of inlet steam mode under large flow extraction condition is proposed.

[0011] However, the above prior art does not mention that a set of primary frequency modulation high standby capacity operation mode can be added inside the coal-fired unit, does not mention that the control logic of economic operation and high standby operation mode can exist at the same time, and does not mention the sliding pressure curve switching control method. SUMMARY

[0012] In order to solve the defects in the prior art, the present application discloses a switching control method for primary frequency modulation high standby operation mode of coal-fired unit, and the technical scheme is as follows:

[0013] A switching control method for primary frequency modulation high standby operation mode of coal-fired unit, characterized in that it comprises the following steps:

[0014] Step 1: Design and parameter determination of primary frequency regulation high standby operation mode: The primary frequency regulation high standby operation mode of the coal-fired unit refers to a mode in which the coal-fired unit can be selected to operate. In this high standby operation mode, the main steam pressure of the coal-fired unit under various operating conditions is higher than that of the economic operation mode. The high standby operation mode is achieved by modifying the unit's sliding pressure operation curve to increase the main steam pressure of the coal-fired unit under various operating conditions. The unit operating under high main steam pressure obtains a primary frequency regulation standby capacity higher than the grid assessment benchmark. The specific standby capacity increment is manually input.

[0015] The parameter acquisition in the high standby operation mode of the coal-fired unit refers to recalculating the sliding pressure operation curve in the high standby mode based on the manually input standby capacity increment.

[0016] Step 2: Logic for switching between high standby operation mode and economic operation mode in primary frequency regulation:

[0017] The switching judgment logic includes the following two aspects:

[0018] ① Judgment logic for switching the economic operation mode to the primary frequency regulation high reserve mode;

[0019] There are two criteria for whether a coal-fired power unit should switch from the economic operation mode to the primary frequency regulation high standby operation mode. Criterion 1 determines whether the unit needs to enter the primary frequency regulation high standby mode based on the statistical analysis results of the real-time frequency stability of the power system. The output result of criterion 1 is TRUE or FALSE.

[0020] Criterion 2 is confirmed by the grid dispatcher from the perspective of the day-ahead and intraday dispatch results and the operation time point, and then the power plant operator is notified. After the operator judges and decides whether it is necessary to enter the primary frequency regulation high standby mode, Criterion 2 directly outputs TRUE or FALSE.

[0021] The results of criterion 1 and criterion 2 are subjected to a logical OR operation. If the output result is TRUE, flag A is set to 1 and flag B is set to 0; otherwise, A is set to 0 and B is set to 1.

[0022] ② Judgment logic for switching from high standby mode to economic operation mode in primary frequency regulation:

[0023] There are two criteria for whether a coal-fired power unit should switch from the primary frequency regulation high standby mode to the economic operation mode. Criterion 1 determines whether the unit needs to enter the primary frequency regulation high standby mode based on the real-time frequency stability statistical analysis results of the power system. The output result of criterion 1 is TRUE or FALSE.

[0024] Criterion 2 is confirmed by the grid dispatcher from the perspective of the day-ahead and intraday dispatch results and the operation time point, and then the power plant operator is notified. After the operator judges and decides whether it is necessary to exit the primary frequency regulation high standby mode, Criterion 2 directly outputs TRUE or FALSE.

[0025] The results of criterion 1 and criterion 2 are subjected to a logical OR operation. If the output result is TRUE, A is set to 1 and B is set to 0; otherwise, A is set to 0 and B is set to 1.

[0026] Step 3: Control method for switching between primary frequency regulation high standby operation mode and economic operation mode:

[0027] Design the switching control logic for the sliding pressure curve of a coal-fired power unit. This switching control logic is designed by using a switching block.

[0028] The data input format of the switching block is as follows: the upper left corner of the switching block is introduced as a judgment quantity, which is an external input. The value of the judgment quantity is 0 or 1. The upper part of the switching block is introduced as the first input quantity, and the right side of the switching block is introduced as the second input quantity.

[0029] The operation logic of the switching block is as follows: when the judgment quantity is 0, the output of the judgment block executes the first input quantity; when the judgment quantity is 1, the output of the judgment block executes the second input quantity.

[0030] The control logic for switching the sliding pressure curve of the coal-fired power unit is as follows:

[0031] Load command N set After economic operation and sliding pressure operation curve f1(N) set Obtain the main steam pressure P for economical operation st1 The result of subtracting the measured main steam pressure P from the actual steam pressure of the unit becomes the second input of the switching block T1:

[0032] f1(N set )-P

[0033] The first input of switching block T1 is 0, the judgment value is B, and the output result is a;

[0034] The aforementioned control logic for switching the sliding pressure curve of the coal-fired power unit further includes the following:

[0035] Load command N set After economic operation and sliding pressure operation curve f1(N) set Obtain the main steam pressure P for economical operation st1 N becomes the first input to switching block T2; set After economic operation and sliding pressure operation curve f2(N) set Obtain the main steam pressure P for economical operation st2, becomes the second input quantity of the switching block T2; the judging quantity of the switching block T2 is B, and the output result is b;

[0036] The main steam pressure P st2 , and becomes the second input quantity of the switching block T3 after being subtracted by the measured main steam pressure P of the unit group:

[0037] f2(N set )-P

[0038] The first input quantity of the switching block T3 is 0, the judging quantity is A, and the output result is d;

[0039] The judging quantity of the switching block T4 is A, the first input quantity is c, the second input quantity is e, and the output result is the real-time calculation result P of the main steam pressure set value set , and satisfies the following relationship:

[0040] c=a / (Ts+1)+b

[0041] e=f1(N set )+d / (Ts+1)

[0042] Wherein, T is an inertia time constant, artificially experienced, and the value range is between 10-25; s is a Laplace operator.

[0043] Beneficial effects

[0044] The main idea of the present application is to add a set of primary frequency modulation high standby control logic on the basis of the original logic, and to add the judgment logic of switching from the economic operation mode to the primary frequency modulation high standby operation mode and switching from the primary frequency modulation high standby operation mode to the economic operation mode. The present application realizes the above-mentioned logic modification, so that the coal-fired unit group runs in the mode of mainly maintaining economic operation under the condition that the power system is relatively safe, and the coal-fired unit group selects to enter the primary frequency modulation high standby mode under the condition that the primary frequency modulation capacity of the power system is small, sacrifices part of the unit operation economy, provides large-capacity standby for the frequency stability of the power system, and solves the problem that the unit operation economy and the frequency modulation capacity are difficult to be considered.

[0045] The switching operation mode only needs to be realized by the operation adjustment of the main steam pressure, the main steam pressure setting mode is modified in the logic configuration diagram, and no additional equipment is needed, so the modification cost and workload are small.

[0046] The inertia link shown in formula (10) and (11) is adopted in the switching control logic designed by the present application, which can effectively avoid the violent fluctuation of the main parameter, ensure the smoothness of the switching process, and maintain the stability of the unit operation. BRIEF DESCRIPTION OF DRAWINGS

[0047] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiments will be briefly introduced as follows. Obviously, the drawings in the following description only constitute some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from these drawings without any creative labor.

[0048] Wherein:

[0049] Figure 1 The logic for switching from the economic operation mode to the primary frequency modulation high standby mode;

[0050] Figure 2 The judgment logic for switching from the primary frequency modulation high standby mode to the economic operation mode;

[0051] Figure 3 The commonly used logic for setting the main steam pressure value of the existing coal-fired unit;

[0052] Figure 4 The main steam pressure value modification logic proposed by the present application;

[0053] Figure 5 Comparison of the sliding pressure curve in the embodiments. DETAILED DESCRIPTION

[0054] The embodiments of the present application will be described in detail below, and examples of the embodiments are shown in the drawings, wherein the same or similar reference signs represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary and are only used to explain the present application, and cannot be understood as a limitation of the present application. On the contrary, the embodiments of the present application include all changes, modifications and equivalents falling within the spirit and scope of the appended claims.

[0055] A switching control method of a primary frequency modulation high standby operation mode of a coal-fired unit, comprising the following steps:

[0056] Step 1: design and parameter calculation of the primary frequency modulation high standby operation mode;

[0057] The primary frequency modulation high standby operation mode of the coal-fired unit refers to a mode in which the coal-fired unit can be selected to enter operation, and the main steam pressure of the coal-fired unit under each working condition in the high standby operation mode is higher than that in the economic operation mode. The high standby operation mode is realized by modifying the sliding pressure operation curve of the unit, improving the main steam pressure of the coal-fired unit under each working condition, and running the unit under high main steam pressure to obtain a primary frequency modulation standby capacity higher than the grid evaluation benchmark, and the specific standby capacity increment is manually inputted by human;

[0058] The parameter calculation in the high standby operation mode of the coal-fired unit includes the following contents:

[0059] ①According to the historical operation data of the coal-fired unit, the relationship between the main steam flow, the main steam pressure and the unit load under all working conditions is calculated, and a corresponding function is established;

[0060] The current sliding pressure operation mode mainly considers the operation economy, and the main steam flow and the main steam pressure corresponding to each load point under the existing sliding pressure operation mode are known quantities, i.e.

[0061] G = k1(N) (1)

[0062] P st = f1(N) (2)

[0063] In the formula, G is the main steam flow, t / h; N is the electric load, MW; P st is the main steam pressure, MPa; u is the main steam valve opening, %; k1 and f1 are known functions fitted according to the field data.

[0064] The flow characteristic curve function G u of the main steam valve is G u = L(u), which needs to be obtained through field test, G x is the main steam flow percentage, %; L is the function relationship from the main steam valve opening to the main steam flow, which is a known function.

[0065] The standby capacity increment of each working condition under the high standby operation mode of primary frequency modulation is artificially specified, a discount function is added in the DCS through manual input, and the function of the standby capacity increment is obtained:

[0066] X = h(N) (3)

[0067] In the formula, X is the standby capacity increment, which represents the primary frequency modulation standby capacity that needs to be added on the basis of the original system, % Pe (Pe is the rated load); the function h is formed after the manual input data.

[0068] Suppose that the electric load under a working condition is N1, and according to the historical operation data, the corresponding main steam valve opening is u1, and according to the valve flow characteristic curve, the corresponding flow percentage is L(u1). The flow percentage under the standby capacity increment requirement (X%) can be solved by the following formula:

[0069] L(u x ) = L(u1) - X%·Pe·L(u1) / N1 (4)

[0070] Where u xis the valve opening corresponding to the operating condition in the high standby mode, %.

[0071] Then u x is solved according to the valve flow characteristic curve.

[0072] Then u x is solved according to the selected sliding pressure operation mode CV, L(u x ), by the steam turbine distribution calculation method. x :

[0073] p x = g(CV, L(u x )) (5)

[0074] In the formula, g is the steam distribution iterative calculation expression.

[0075] The corrected main steam pressure in other operating conditions is obtained by using the method under the condition Other operating conditions The main steam pressure setting value curve in the high standby mode is

[0076] P st = f2(N) (6).

[0077] Step 2: The switching judgment logic of the primary frequency regulation high standby operation mode and the economic operation mode;

[0078] ① The judgment logic of switching from the economic operation mode to the primary frequency regulation high standby mode.

[0079] There are two criteria for switching from the economic operation mode to the primary frequency regulation high standby operation mode of the coal-fired unit, and the judgment logic block diagram is shown in Figure 1 .

[0080] Criterion 1: The average relative error of the unit slip in the current period of time is large, which satisfies the following formula,

[0081]

[0082] Wherein, n is the statistical time length, s; Δω is the steam turbine slip, rad / min; γ is the critical judgment value of the speed deviation, which is artificially set and can be selected as 5-8 rad / min.

[0083] At the same time, whether to exit the economic operation mode is confirmed by the operator, and the criterion 1 outputs the judgment result TRUE or FALSE.

[0084] Criterion 2: human judgment. According to the day-ahead / day-ahead dispatching plan, whether the power system is facing high power output of new energy and extra-high voltage transmission in the current and near future, whether the penetration rate is greater than the critical parameter, if so, the power grid dispatcher notifies the power plant operator to select the high standby mode of primary frequency modulation of thermal power units; whether the current and future are facing special moments of maintaining high stability of the power grid, such as whether it is in the holiday time, whether the power grid needs to carry out disturbance test, etc., if so, the power grid dispatcher notifies the power plant operator to select the high standby mode of primary frequency modulation of thermal power units; and other reasons. The result of human judgment is called by the operator's direct command, and the output result of criterion 2 is TRUE or FALSE.

[0085] The judgment results of criterion 1 and criterion 2 are subjected to or logical judgment operation, and when the output result is TRUE, A is set to 1 and B is set to 0, otherwise A is set to 0 and B is set to 1.

[0086] 2. The judgment logic of switching from the high standby mode of primary frequency modulation to the economic operation mode.

[0087] The judgment logic block diagram is shown in Figure 2 .

[0088] Criterion 1: the average relative error of unit swing in the current period of time is large, which satisfies the following formula,

[0089]

[0090] Then the operator confirms whether to exit the high standby mode of primary frequency modulation, and criterion 1 outputs TRUE or FALSE.

[0091] Criterion 2: human judgment. The result of human judgment is executed by the operator's direct command, and criterion 2 outputs TRUE or FALSE.

[0092] Criterion 1 and criterion 2 are subjected to or logical judgment operation, and when the output result is TRUE, A is set to 0 and B is set to 1, otherwise A is set to 1 and B is set to 0.

[0093] Step 3: switching control method of the high standby mode of primary frequency modulation and the economic operation mode.

[0094] The existing conventional sliding pressure curve setting function is shown in Figure 3 , and the main steam pressure switching logic proposed by the application is shown in Figure 4 .

[0095] The data input format of the switching block T is as follows: the upper left corner of the switching block is used as a judgment value, which is an external input and can be either 0 or 1. The upper part of the switching block is used as the first input value, and the right side of the switching block is used as the second input value. The operation logic of the switching block is as follows: when the judgment value is 0, the output of the switching block executes the first input value; when the judgment value is 1, the output of the switching block executes the second input value.

[0096] The input quantity for the main steam pressure switching operation logic is N. set and P, N set is the current input load command, MW; P is the current measured main steam pressure, MPa.

[0097] The decision variable for switching block T1 is B, the first input is 0, and the second input is f1(N). set )-P, the output result is a;

[0098] The decision variable for switching block T2 is B, and the first input variable is f1(N). set The second input is f2(N). set The output result is b;

[0099] The decision variable for switching block T3 is A, the first input is 0, and the second input is f2(N). set -P, the output result is d;

[0100] The decision value for switch block T4 is A, the first input value is c, the second input value is e, and the output value is the main steam pressure setpoint P. set And satisfy the following relationship:

[0101] c = a / (Ts+1) + b (9)

[0102] e = f1(N) set )+d / (Ts+1) (10)

[0103] Where T is the inertial time constant, which is given empirically and ranges from 10 to 25. By adding this inertial logic, the smoothness of parameter changes during the switching process is ensured, and fluctuations are reduced.

[0104] Implementation 1

[0105] Taking a 350MW supercritical condensing thermal power unit as the implementation object, data such as unit load, main steam flow, and valve opening were collected from the unit's historical operating data. After removing outliers, linear fitting was used to fit the data, and the following linear fitting equation is given:

[0106] G = 3.02 N

[0107]

[0108] Simultaneously, on-site valve tests were conducted, including valve opening tests under different loads. Unit load, main steam flow rate, and overall valve opening were recorded. Combined with historical operating data, the valve flow characteristic curve was obtained through data fitting, as shown in the following formula:

[0109] G u = -2.319 × 10⁻⁶ u 4 +0.0008123u 3 -0.1014u 2 +5.383u-3.909(0≤u

[0110] ≤100)

[0111] In addition, the reserve capacity increment is manually set, as shown in the table below:

[0112]

[0113] Based on the table above, the following equations are fitted:

[0114]

[0115] Selecting the 50% Pe operating condition, a 1.5% Pe adjustment margin is required. Historical operating data shows that during stable operation at 50% rated load, the main steam valve opening is approximately 40%. Therefore, artificially setting a 1.5% Pe flow increment is necessary, based on G... u From the formula, the valve opening is 37.8%. Therefore, in the primary frequency regulation high standby mode, the main steam valve opening corresponding to 50% Pe is 37.8%. Using the Flügger formula and turbine variable operating condition calculations, the main steam pressure after the main steam valve change at this load point is approximately 16.5 MPa. Using the above methods, the pressure change value at the full load point was calculated, and the sliding pressure curve in the primary frequency regulation high standby mode was obtained:

[0116]

[0117] Comparison of sliding pressure curves under economic operation mode and primary frequency regulation high reserve operation mode. Figure 5 As shown.

[0118] Then, in the target unit's DCS, add a new logical page, according to... Figure 1 and Figure 2 The design block diagram is logically configured, with γ set to 8 rad / min and n set to 120. In the target DCS, locate the logic page for the sliding pressure curve setting and configure it accordingly. Figure 3 The logic shown is modified as follows: Figure 4 The logic is then implemented. After downloading and running the logic, the objective of this invention can be achieved.

[0119] This invention proposes an operating mode for generating units to provide high-capacity primary frequency regulation reserve. By sacrificing some economic efficiency, the unit can provide high-capacity primary frequency regulation reserve for the power system, maximizing its support for power system stability. Furthermore, this invention designs a method for obtaining parameters, a switching judgment logic, and a switching control method for this high-reserve operation mode, enabling smooth switching between the two modes. The modification cost and workload are relatively small, and it is easy to implement on-site.

[0120] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention. The scope of protection claimed by the appended claims and their equivalents is defined.

Claims

1. A switching control method for a primary frequency regulation high standby operation mode of a coal-fired power unit, characterized in that: Step 1: Design and parameter determination of the primary frequency regulation high standby operation mode; The primary frequency regulation high standby operation mode of the coal-fired unit refers to a mode in which the coal-fired unit can be selected for operation. In this mode, the coal-fired unit has a high primary frequency regulation standby capacity under various operating conditions; This high standby operation mode is achieved by modifying the unit's sliding pressure operation curve to increase the main steam pressure of the coal-fired unit under various operating conditions. The unit operating under high main steam pressure obtains a primary frequency regulation standby capacity higher than the grid assessment benchmark. The specific standby capacity increment can be manually input; The parameter determination of the coal-fired unit's high standby operation mode refers to recalculating the sliding pressure operation curve under the high standby operation mode based on the manually input standby capacity increment; Step 2: The logic for switching between high-standby operation mode and economic operation mode in primary frequency regulation includes two aspects: ① Judgment logic for switching the economic operation mode to the primary frequency regulation high reserve mode; There are two criteria for whether a coal-fired power unit should switch from the economic operation mode to the primary frequency regulation high standby operation mode. Criterion 1 determines whether the unit needs to enter the primary frequency regulation high standby mode based on the statistical analysis results of the real-time frequency stability of the power system. The output result of criterion 1 is TRUE or FALSE. Criterion 2 is confirmed by the grid dispatcher from the perspective of the day-ahead and intraday dispatch results and the operation time point, and then the power plant operator is notified. After the operator judges and decides whether it is necessary to enter the primary frequency regulation high standby mode, Criterion 2 directly outputs TRUE or FALSE. The results of criterion 1 and criterion 2 are subjected to a logical OR operation. If the output result is TRUE, flag A is set to 1 and flag B is set to 0; otherwise, A is set to 0 and B is set to 1. ② Judgment logic for switching from high standby mode to economic operation mode in primary frequency regulation: There are two criteria for whether a coal-fired power unit should switch from the primary frequency regulation high standby mode to the economic operation mode. Criterion 1 determines whether the unit needs to enter the primary frequency regulation high standby mode based on the statistical analysis results of the real-time frequency stability of the power system. The output result of criterion 1 is TRUE or FALSE. Criterion 2 is confirmed by the grid dispatcher from the perspective of the day-ahead and intraday dispatch results and the operation time point, and then the power plant operator is notified. After the operator judges and decides whether it is necessary to exit the primary frequency regulation high standby mode, Criterion 2 directly outputs TRUE or FALSE. The results of criterion 1 and criterion 2 are subjected to a logical OR operation. If the output result is TRUE, A is set to 1 and B is set to 0; otherwise, A is set to 0 and B is set to 1. Step 3: Switching control logic between primary frequency regulation high standby operation mode and economic operation mode, including the following: designing the switching control logic for the sliding pressure curve of the coal-fired unit, which is implemented using a switching block; The data input format of the switching block is as follows: the upper left corner of the switching block is introduced as a judgment quantity, which is an external input. The value of the judgment quantity is 0 or 1. The upper part of the switching block is introduced as the first input quantity, and the right side of the switching block is introduced as the second input quantity. The operation logic of the switching block is as follows: when the judgment quantity is 0, the output of the judgment block executes the first input quantity; when the judgment quantity is 1, the output of the judgment block executes the second input quantity. The control logic for switching the sliding pressure curve of the coal-fired power unit is as follows: Load command N set After economic operation and sliding pressure operation curve f1(N) set Obtain the main steam pressure P for economical operation st1 The result of subtracting the measured main steam pressure P from the actual steam pressure of the unit becomes the second input of the switching block T1: f1(N set )-P The first input of switching block T1 is 0, the judgment value is B, and the output result is a; The aforementioned control logic for switching the sliding pressure curve of the coal-fired power unit further includes the following: Load command N set After economic operation and sliding pressure operation curve f1(N) set Obtain the main steam pressure P for economical operation st1 N becomes the first input to switching block T2; set After economic operation and sliding pressure operation curve f2(N) set Obtain the main steam pressure P for economical operation st2 This becomes the second input of switching block T2; the decision value of switching block T2 is B, and the output result is b. The main steam pressure P st2 The result of subtracting the measured main steam pressure P from the actual steam pressure of the unit becomes the second input value of the switching block T3: f2(N set )-P The first input of switching block T3 is 0, the judgment value is A, and the output result is d; The decision value of switch block T4 is A, the first input value is c, the second input value is e, and the output result is the real-time calculation result P of the main steam pressure setpoint. set And satisfy the following relationship: c = a / (Ts+1) + b (9) e=f1(N set )+d / (Ts+1) (10) Where T is the inertial time constant, which is given empirically and ranges from 10 to 25; s is the Laplace operator.

2. The switching control method for the primary frequency regulation high standby operation mode of a coal-fired unit according to claim 1, characterized in that: The parameter determination includes the following: ①Based on historical operating data of coal-fired units, calculate the relationship between main steam flow, main steam pressure and unit load under all operating conditions, and establish corresponding functions; ② Obtain the flow characteristic curve of the main steam valve through field tests; ③ The reserve capacity increment for primary frequency regulation is set manually; ④ Calculate the sliding pressure operation curve under the high standby operation mode of primary frequency regulation.

3. The switching control method for the primary frequency regulation high standby operation mode of a coal-fired unit according to claim 1, characterized in that: Criterion 1 in the judgment logic for switching from the economic operation mode to the primary frequency regulation high reserve mode is: the average relative error of the unit slip over a period of time is used to measure the frequency stability of the power system. When the average relative error is large, the following formula is satisfied: Where n is the statistical duration, s; Δω is the turbine slip, rad / min; γ is the critical judgment value of the speed deviation, selected as 5-8 rad / min; The above judgment result is logically ANDed with the operator's confirmation of whether to exit the economic operation mode. Criterion 1 outputs the judgment result TRUE or FALSE.

4. The switching control method for the primary frequency regulation high standby operation mode of a coal-fired unit according to claim 3, characterized in that: The criterion 1 in the judgment logic for switching from the high reserve mode to the economic operation mode of the primary frequency regulation is: the average relative error of the unit slip over a period of time is used to measure the frequency stability of the power system. When the average relative error is small, the following formula is satisfied: The above judgment result is combined with the operator's confirmation of whether to exit the high standby mode of frequency modulation. The judgment result of criterion 1 is TRUE or FALSE.

5. An electronic device, characterized in that, It includes a processor and a memory; the memory stores computer-readable instructions, and the processor is configured to execute the computer-readable instructions, wherein the computer-readable instructions, when executed, perform the method according to any one of claims 1 to 4.

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