A coordinated control method for generator sets

Abstract

The present invention discloses a coordinated control method for a generator set, and the control method is as follows: S1: adopting a machine-boiler coordinated mode to operate the boiler and the steam turbine in a fixed-slip-constant pressure mode; S2: the machine-boiler coordinated mode sends the power deviation signal P0-PE to the steam turbine controller to form a power closed-loop control, and at the same time adds the power deviation signal to the nonlinear link and the feedforward signal P0 to form the boiler main controller feedforward signal; S3: during the power closed-loop control, the steam turbine adopts a dynamic load forward feedback mode to achieve a rapid response of the dynamic process of the steam turbine; S4: the boiler main controller feedforward signal corrects the fuel calorific value in the boiler in real time through a fuel correction loop. The present invention provides a coordinated control method for a generator set, which can achieve a rapid response of the dynamic process of the steam turbine through the machine-boiler coordinated mode when implementing coordinated control; so that the output of the steam turbine unit is adapted to the load requirements of the power grid, and the two energy supply and demand balance relationships are reasonably maintained.

Description

Technical Field

[0001] The present invention relates to the field of thermal power generating sets, and in particular to the field of generating set coordinated control systems. Background Art

[0002] The proportion of thermal power generating units in the power grid is getting larger and larger. Due to the change of power consumption structure, the peak-to-valley difference of load is gradually increasing. Therefore, large units are required to have the ability to operate with variable loads in order to quickly meet the needs of load changes and participate in power grid frequency regulation. Whether the output power of thermal power units is consistent with the load requirements reflects the balance relationship between the energy supply and demand between the units and the external power grid. The main steam pressure reflects the balance relationship between the energy supply and demand between the boiler and the steam turbine generator inside the unit. The coordinated control system is set up to achieve these two balance relationships. When the coordinated control system is in operation, the boiler, steam turbine and generator with large differences in dynamic characteristics are controlled as a unified whole. It organically and coordinately controls the boiler's fuel, air supply, induced draft and feed water, as well as the opening of the steam turbine regulating door, so as to minimize the impact of various variables. Most of them have the problem of tight debugging time and insufficient debugging during the infrastructure debugging period, which leads to the problem of slow load tracking and inability to adapt to various working conditions after the unit is put into production. Summary of the invention

[0003] Purpose of the invention: In order to overcome the deficiencies in the prior art, the present invention provides a method for coordinated control of a generator set, which can achieve rapid response of the dynamic process of the turbine through coordination between the machine and the boiler when implementing coordinated control; make the output of the turbine set compatible with the load requirements of the power grid, and reasonably maintain the balance between the supply and demand of the two energies.

[0004] Technical solution: To achieve the above purpose, the technical solution of the present invention is as follows:

[0005] A coordinated control method for a generator set, the control method comprising:

[0006] S1: The boiler and steam turbine are operated in a fixed-sliding-constant pressure mode by using the boiler-turbine coordination mode;

[0007] S2: The power deviation signal P0-PE is sent to the steam turbine controller in a coordinated manner to form a power closed-loop control. At the same time, the power deviation signal is added to the nonlinear link and the feedforward signal P0 to form the boiler main controller feedforward signal;

[0008] S3: During power closed-loop control, the steam turbine uses dynamic load forward feedback to achieve rapid response of the dynamic process of the steam turbine, so that the output of the steam turbine unit is compatible with the grid load requirements;

[0009] S4: The feedforward signal of the boiler main controller corrects the fuel calorific value in the boiler in real time through the fuel correction loop to achieve a balance between energy supply and demand between the boiler and the turbine.

[0010] Furthermore, in S2, the adjustment steps of the machine-boiler coordination mode are:

[0011] S11: Assuming that the load command P0 increases, the power command signal is sent to the steam turbine controller and the boiler controller in parallel, the steam turbine controller quickly opens the steam turbine regulating valve, the actual main steam pressure Pt decreases, the boiler releases the stored heat, and the steam flow rate increases to meet the load increase requirements;

[0012] S12: Based on the load change rate set by the unit, the load instruction P0 is used as a feedforward signal to the boiler to compensate for the inertia and delay of the boiler;

[0013] S13: When the steam pressure deviation |Ps--Pt|≥△ of the dead zone component, the dead zone component will limit the turbine regulating steam valve from opening further;

[0014] S14: The steam pressure deviation signals Ps--Pt are simultaneously sent to the boiler controller to adjust the boiler to supplement the additional fuel amount caused by the change in boiler heat storage due to the change in steam pressure;

[0015] S15: When the adjustment is completed, the equilibrium state of P0=PE and Pt=Ps is reached.

[0016] Furthermore, the load instruction of the machine-boiler coordination mode is generated through a load instruction generation loop, and a load rate function is constructed to take the smaller value than the operator's set value, and automatic speed reduction in the high load section is achieved through the automatically generated load instruction.

[0017] Furthermore, the adjustment step of the boiler main controller in S2 is:

[0018] S21: Modify the load-coal quantity function;

[0019] S22: Separate the dynamic and static parameters of the boiler master regulator;

[0020] S23: After the load change ends, there is a delay of 60 seconds and the boiler master control switches from dynamic parameters to static parameters;

[0021] S24: When the steam turbine master control is in manual mode, the boiler master control is automatically switched to manual mode;

[0022] S25: Add boiler master control lockout conditions.

[0023] Furthermore, in S3, when performing rapid response to the dynamic process of the steam turbine, the main steam pressure in the pressure pull-back loop function is first modified, and then in the AGC mode, the third-order inertia of the steam turbine instruction is cancelled, and the AGC mode load grabbing loop is added.

[0024] Furthermore, the steps of generating the main steam pressure through the main steam pressure setting generation circuit are as follows:

[0025] S31: Because the primary frequency modulation is a transient mode, the influence of the primary frequency modulation on the main steam pressure setting is eliminated;

[0026] S32: Change the pressure setting from third-order inertia to first-order inertia, and the inertia time is 150s;

[0027] S33: Modify the sliding pressure rate curve under normal working conditions.

[0028] Furthermore, in S4, the adjustment steps of the fuel correction circuit are:

[0029] S41: Construct a BTU automatic regulator, set the theoretical fuel quantity under the current load according to the unit load setting or the actual power, compare it with the corrected fuel quantity after BTU correction, enter the PID regulator to adjust the BTU output coefficient, and its control dead zone is ±4t / h;

[0030] S42: BTU output is a coefficient, its physical meaning = designed fuel quantity / actual fuel quantity, adjustable range is 0.8-1.2;

[0031] S43: The fuel calibration circuit has two modes: manual and automatic;

[0032] S44: When any of the following situations occurs: unit load change, coal mill start / stop within 5 minutes, power deviation exceeds 10MW, or main steam pressure deviation exceeds 1MPa, BTU regulation maintains the current output in automatic state;

[0033] S45: When the fuel master control is manual or the unit load is less than 300MW, the BTU adjustment is switched to manual mode.

[0034] Furthermore, in S42, when BTU is less than 1, the actual coal consumption is greater than the designed coal consumption; when BTU is greater than 1, the actual coal consumption is less than the designed coal consumption.

[0035] Beneficial effects: The present invention sends the unit load command directly to the boiler and steam turbine main controller, so that the unit can obtain faster load response. At the same time, the power correction and front-end pressure correction loops are used as lag corrections in load changes, so that the unit can accurately control power and pressure. When the generator set implements coordinated control, the turbine adopts a dynamic load forward feedback method to achieve rapid response of the turbine dynamic process, so that the output of the turbine unit is adapted to the grid load requirements. The boiler main controller feedforward signal corrects the fuel calorific value in the boiler in real time through the fuel correction loop to achieve a balance between energy supply and demand between the boiler and the steam turbine, and then can coordinate the actions of both sides of the machine and the boiler well, reasonably maintain the two energy supply and demand balance relationships, and take into account both load response performance and internal operating parameter stability. The adjustment quality of the main operating parameters of the unit is improved, so that the unit output is adapted to the grid load requirements and meets the requirements of the unit's rapid response AGC. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Attached Figure 1 It is a step diagram of the coordinated control method of the generator set;

[0037] Attached Figure 2 This is the principle block diagram of the load control object of the generator set;

[0038] Attached Figure 3 This is the logic block diagram of the coordinated control of the unit. DETAILED DESCRIPTION

[0039] The present invention will be further described below in conjunction with the accompanying drawings.

[0040] As attached Figure 1-3 : A coordinated control method for a generator set, the control method is:

[0041] S1: The boiler and steam turbine are operated in a fixed-sliding-constant pressure mode by using the boiler-turbine coordination mode;

[0042] S2: The power deviation signal P0-PE is sent to the steam turbine controller in a coordinated manner to form a power closed-loop control. At the same time, the power deviation signal is added to the nonlinear link and the feedforward signal P0 to form the boiler main controller feedforward signal;

[0043] S3: During power closed-loop control, the steam turbine uses dynamic load forward feedback to achieve rapid response of the dynamic process of the steam turbine, so that the output of the steam turbine unit is compatible with the grid load requirements;

[0044] S4: The feedforward signal of the boiler main controller corrects the fuel calorific value in the boiler in real time through the fuel correction loop to achieve a balance between energy supply and demand between the boiler and the turbine.

[0045] The boiler and turbine of the generator set are two relatively independent devices. From the perspective of unit load control, the generator set is a multivariable control object with interrelated variables. With appropriate assumptions, it can be regarded as an interrelated controlled object with two inputs and two outputs. Figure 2 As shown; where TD = turbine master control instruction; μT = turbine regulating valve opening; PE = unit load; BD = boiler master control instruction; μB = boiler combustion rate and corresponding feed water volume; Pt = machine front pressure.

[0046] According to the characteristics of the thermal system, the dynamic characteristics of the load control object are: when the turbine valve opening is activated, the controlled quantities PE and Pt respond very quickly, that is, the thermal inertia is small; when the boiler combustion rate changes, the responses of PE and Pt are very slow, that is, the thermal inertia is large. The fast and slow responses are the big differences in the dynamic characteristics of the boiler object. Therefore, the two energy supply and demand relationships inside the generator set restrict each other, and there is an inherent contradiction between the external load response performance and the stability of the internal operating parameters. According to this characteristic, when implementing coordinated control, the generator set must coordinate the actions on both sides of the boiler well and reasonably maintain the balance of the two energy supply and demand relationships to take into account both the load response performance and the stability of the internal operating parameters.

[0047] The unit boiler coordination control system consists of boiler coordination mode (CCS), boiler tracking mode (BF), turbine tracking mode (TF) and basic mode (BH); when the unit is operating normally, the boiler coordination mode is generally adopted and the unit operates in a fixed-slide-constant pressure mode.

[0048] Boiler-machine coordination mode CCS: refers to controlling the boiler-turbine generator set as a whole, coordinating the boiler and turbine to operate in an automatic state through the control loop, and issuing instructions to the automatic control system of the boiler and turbine to adapt to the needs of load changes and maximize the frequency regulation and peak regulation capabilities of the unit. The execution level it directly acts on is the boiler fuel control system and the turbine control system; Boiler tracking mode BF: It is a control mode in which the turbine controls the power and the boiler controls the steam pressure to adapt the boiler load to the needs of turbine load changes; Turbine tracking mode TF: According to the requirements of the power grid load, the power regulator directly controls the fuel amount B of the boiler; As the heat input of the boiler increases or decreases, the main steam pressure pt will change. At this time, the main steam pressure regulator will continuously change the opening of the steam regulating valve to maintain the stability of the main steam pressure. The opening or closing of the steam regulating valve means the change of the unit output, thereby adapting to the needs of the power grid load; When the unit is operating normally, the boiler-machine coordination mode is generally adopted, and it operates in a fixed-sliding-constant pressure mode; Basic mode BH: In multiple tests, it is very important to control the probability of making the first type of error. Bonferroni once proposed to use a / m as the a value for each subtest; however, the disadvantage of this correction method is that it is too conservative. For example, when comparing whether there are differences between 10 groups, If a=0.05, then the α value for each test is Therefore, the null hypothesis is rarely or almost never rejected; therefore, Benjamini and Hochberg proposed a new method to control the accuracy of the test by controlling the size of FDR.

[0049] From the study of the dynamic characteristics of the generator set object, it is known that the dynamic characteristics of the main operating parameters of the unit, namely the unit power and the main steam pressure, under the control of the generator set and the boiler, are very different. The starting point of the design of the generator set boiler coordinated control system is that the rapid load response of the unit and the necessary stability of the main operating parameters of the unit must be considered at the same time. In view of this, the basic control strategy of the boiler coordinated control system is to speed up the boiler combustion rate control rate as much as possible, and appropriately sacrifice the boiler stability to meet the real-time power demand.

[0050] Unit load changes before control system optimization:

[0051] 1) When the unit change rate is set to 9MW / min, the load response is slow, with the actual rate being around 5MW / min. The intermediate point temperature, main steam temperature and reheat steam temperature fluctuate greatly, and the water-cooled wall is prone to overheating, which cannot meet the requirements of rapid load response and stable operation of the unit.

[0052] 2) The variable load feedforward of the unit is a constant variable load quantity, which is only related to the variable load rate and cannot be automatically adjusted according to different working conditions such as load and pressure, thus causing the press furnace to be out of adjustment during the continuous load change process.

[0053] 3) The fuel correction circuit is not put into operation. The coal quality of the current unit has changed compared with the trial operation period and has a certain volatility; the original control logic has not been corrected accordingly, which will cause fluctuations in important parameters such as main steam pressure, temperature and superheat under the condition of coal quality changes.

[0054] 4) The dynamic and static states of the boiler master control are not separated. During the steady state and load change process of the unit, the dynamic characteristics of the boiler and the steam turbine are different; the current logic boiler master control uses a single parameter and does not distinguish between dynamic and static states, which easily causes overshoot in the dynamic process and undershoot in the static process.

[0055] According to the on-site conditions, the coordinated control ideas of the unit boiler are:

[0056] 1) When the unit load changes, the primary air changes to speed up the boiler response speed, allowing the main steam pressure to change slightly. After the load stabilizes, the main steam pressure is adjusted by the boiler combustion rate. The control effect achieved is that in the process of changing the unit power, the unit load response requirements are met. At the same time, the main steam pressure and other main operating parameters of the unit are guaranteed to be relatively stable, and the dynamic and static deviations of the main steam pressure are relatively small. Therefore, the unit optimization control strategy adopts a coordinated control method based on boiler following. The unit load command is sent directly to the boiler and steam turbine main controller, so that the unit can obtain a faster load response. At the same time, the power correction and pre-machine pressure correction loops are used as lag corrections in load changes, so that the unit can accurately control power and pressure; see the optimized control strategy. Figure 3 .

[0057] In said S2, the adjustment steps of the boiler-machine coordination mode are as follows: wherein P0: unit load instruction; Ps: unit main steam pressure setting value; PE: unit actual load; Pt: actual main steam pressure; BID: boiler input instruction;

[0058] S11: Assuming that the load command P0 increases, the power command signal is sent to the steam turbine controller and the boiler controller in parallel, the steam turbine controller quickly opens the steam turbine regulating valve, the pressure Pt in front of the machine decreases, the boiler releases the stored heat, and the steam flow rate increases to meet the load increase requirements;

[0059] S12: Since the boiler responds slower to load changes than the turbine, the load instruction P0 is used as the feedforward signal sent to the boiler according to the load change rate set by the unit to compensate for the inertia and delay of the boiler; at the same time, the integral link of the boiler main controller performs closed-loop correction on the pressure before the machine to achieve the purpose of accurately controlling the main steam pressure;

[0060] S13: If the rate and amplitude of the load requirement increase is large, the steam pressure Pt may change too much; when the steam pressure deviation |Ps--Pt|≥△ of the dead zone component, the dead zone component will limit the turbine regulating steam valve from opening further to ensure that the steam pressure Pt changes within the allowable range;

[0061] S14: The steam pressure deviation signals Ps--Pt are simultaneously sent to the boiler controller to strengthen the regulation of the boiler to supplement the additional fuel caused by the change in boiler heat storage due to the change in steam pressure;

[0062] S15: When the adjustment is finished, the equilibrium state of P0 = PE, Pt = Ps is reached. The characteristic of this system is that it can compensate for the inertia and delay of the boiler and strengthen the control effect on the boiler.

[0063] Considering the relatively large delay and inertia of the boiler and its subsystems, in order to achieve rapid response of the unit's dynamic process, the unit adopts a dynamic variable load feedforward method. The feedforward amount is automatically adjusted according to the current load, pressure, load span and change rate to adapt to the various operating conditions of the boiler; the loop acts on the fuel, feed water, superheat, cooling water, primary air, supply air, induced draft and denitrification related sub-loops; optimize the fuel correction loop (BTU) to adapt to changes in coal quality and ensure real-time response of the unit load.

[0064] The load command of the machine-boiler coordination mode is generated by the load command generation loop, and the load change rate is automatically limited. Considering that the output of the coal mill in the high-load section is close to the limit, the pulverized coal speed is significantly slowed down, and the boiler inertia is significantly increased. In order to ensure the safety of the unit and the boiler is not over-pressurized, a load rate function is constructed to take the smaller value than the operator's set value, and the automatic speed reduction of the high-load section is achieved through the automatically generated load command; as shown in Table 1.

[0065] Table 1 Unit load-rate function table

[0066] Load command (MW) Load changing rate (MW / min) 0 18 500 18 590 18 600 12 610 9 660 6

[0067] The adjustment steps of the boiler main controller in S2 are:

[0068] S21: Modify the load-coal quantity function to ensure the accuracy of load linear feedforward;

[0069] S22: Separate the dynamic and static parameters of the boiler master control regulator; in static state, strengthen the proportional, integral and differential effects to ensure the stability of the main steam pressure and the energy balance between the boiler and the steam turbine; in dynamic state, weaken the proportional, integral and differential effects to avoid overshoot of the boiler master control due to pressure lag;

[0070] S23: After the load change ends, there is a delay of 60 seconds and the boiler master control switches from dynamic parameters to static parameters;

[0071] S24: When the steam turbine master control is in manual mode, the boiler master control is automatically switched to manual mode;

[0072] S25: Add the boiler master control lockout condition to avoid the boiler master control integral saturation caused by the factor loop output exceeding the limit.

[0073] Table 2 Boiler load - linear function table

[0074] Load command (MW) Coal volume (t / h) 0 0 211.2 85 264 101 330 125.6 495 190 660 260 700 263.3

[0075] Table 3 Boiler master control lockout conditions

[0076]

[0077] In the S3, when the dynamic process of the steam turbine is being rapidly responded, the main steam pressure in the pressure pull-back loop function (such as Tables 4 and 5) is first modified. When the high-pressure section is over-pressured, the pull-back loop is strengthened to ensure the safety of the unit; in other cases, the pull-back loop is weakened to ensure the accuracy of load regulation; then in the AGC mode, the third-order inertia of the steam turbine command is canceled to reduce the load response time; and the AGC mode load grabbing loop is added; in the AGC mode, when the load increases, the steam turbine load command is increased by 2MW to improve the load response rate; when the load change ends, the 2MW additional command disappears. Automatic Generation Control (AGC) is an important function in the energy management system EMS. It controls the output of the frequency-modulating unit to meet the ever-changing power needs of users and keep the system in an economical operating state;

[0078] Table 4 Steam turbine pull-back loop function table

[0079] Pressure deviation PV-SP(MPa) Power(MW) -2 -8 -1 -2 -0.5 0 0.5 0 1 2 2 8

[0080] Table 5 Turbine pull-back loop correction function table

[0081] Main steam pressure(MPa) Gain 0 1 10 1 20 1 24 1 25 3 26 5

[0082] The steps of generating the main steam pressure through the main steam pressure setting generation circuit are as follows:

[0083] S31: Because the primary frequency modulation is a transient mode, the influence of the primary frequency modulation on the main steam pressure setting is eliminated;

[0084] S32: Change the pressure setting from third-order inertia to first-order inertia, and the inertia time is 150s;

[0085] S33: Modify the normal operating condition sliding pressure rate curve (as shown in Table 6).

[0086] Table 6 Main steam pressure setting sliding pressure rate curve

[0087] Load change rate (MW / min) Original sliding pressure rate (MPa / min) New sliding pressure rate (MPa / min) 0 0.1 0.1 6 0.15 0.25 10 0.4 0.45 13.2 0.6 0.6

[0088] Boiler variable load feedforward control loop: In order to speed up the boiler response and meet the AGC requirements, the variable load feedforward loop is rebuilt to control the boiler energy in advance and reduce its system inertia. The feedforward amount is automatically adjusted according to the current load, pressure, load span and change rate to adapt to the various working conditions of the boiler; the loop acts on the fuel, feed water, superheat, desuperheating water, primary air, supply air, induced draft and denitrification related sub-loops.

[0089] The boiler fuel correction circuit, the main control adjustment and fuel setting of the unit boiler are based on the designed coal type. By adjusting the heat entering the furnace, the water, coal, wind and other sub-circuits are coordinated with each other to achieve the purpose of accurately controlling the energy output and matching the steam turbine demand. Therefore, when the quality of the coal entering the furnace changes greatly, the reference point of the boiler main control coal quantity adjustment has deviated from the original value, causing large fluctuations in the main steam pressure and steam temperature, and at the same time causing the water-coal and wind-coal ratios to approach the limit, without adjustment margin. Therefore, it is necessary to correct the fuel calorific value in real time to ensure that the control reference point of the boiler energy remains unchanged and realize adaptive adjustment under coal quality fluctuations. According to the above requirements, the fuel correction circuit (BTU) was redesigned to achieve this function.

[0090] In S4, the adjustment steps of the fuel correction circuit are:

[0091] S41: Construct a BTU automatic regulator, set the theoretical fuel quantity under the current load according to the unit load setting or the actual power, compare it with the corrected fuel quantity after BTU correction, enter the PID regulator to adjust the BTU output coefficient, and its control dead zone is ±4t / h;

[0092] S42: BTU output is a coefficient, and its physical meaning = designed fuel quantity / actual fuel quantity, and the adjustable range is 0.8-1.2; when BTU < 1, it indicates that the actual coal type is poor, and the actual coal consumption is greater than the designed coal quantity; when BTU > 1, it indicates that the actual coal type is good, and the actual coal consumption is less than the designed coal quantity;

[0093] S43: The fuel correction circuit has two modes: manual and automatic. Under normal circumstances, the BTU circuit automatically adjusts to adapt to the slow changes in coal quality. When the coal quality changes drastically or abnormal operating conditions occur and the coal quantity needs to be changed quickly, this circuit can be switched to manual mode for manual addition and subtraction. When the BTU output is increased (decreased) by 0.01, the actual coal quantity is reduced (increased) by 1% of the current coal quantity.

[0094] S44: When any of the following situations occurs: unit load change, coal mill start / stop within 5 minutes, power deviation exceeds 10MW, or main steam pressure deviation exceeds 1MPa, BTU regulation maintains the current output in automatic state to avoid the influence of system disturbance on regulation;

[0095] S45: When the fuel master control is manual or the unit load is less than 300MW, the BTU adjustment is switched to manual mode.

[0096] After the coordinated control system of the unit is working, the load can be increased or decreased quickly while ensuring the stability of the main steam pressure, main reheat steam temperature and other parameters. The actual load change rate reaches more than 1.3% Pe / min, which improves the regulation quality of the main operating parameters of the unit, makes the unit output compatible with the grid load requirements, and meets the requirements of the unit's rapid response to AGC.

[0097] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. A person skilled in the art may make several improvements and changes without departing from the above principles of the present invention, and these improvements and changes are also considered to be within the protection scope of the present invention.

Claims

1. A method for coordinated control of a generator set, characterized in that: The control method is: S1: The boiler and steam turbine are operated in a fixed-sliding-constant pressure mode by using the boiler-turbine coordination mode; S2: The power deviation signal P0-PE is sent to the steam turbine controller in a coordinated manner to form a power closed-loop control. At the same time, the power deviation signal is added to the nonlinear link and the feedforward signal P0 to form the boiler main controller feedforward signal; In S2, the adjustment steps of the machine-boiler coordination mode are: S11: Assuming that the unit load command P0 increases, the power command signal is sent to the turbine controller and the boiler controller in parallel, the turbine controller quickly opens the turbine regulating steam valve, the actual main steam pressure Pt decreases, the boiler releases the stored heat, and the steam flow rate increases to meet the load increase requirements; S12: According to the load change rate set by the unit, the unit load instruction P0 is used as the feedforward signal sent to the boiler to compensate for the inertia and delay of the boiler; at the same time, the integral link of the boiler main controller performs closed-loop correction on the pressure before the unit to achieve the purpose of accurately controlling the main steam pressure; S13: When the steam pressure deviation |Ps-Pt|≥ the change amount of the dead zone component, the dead zone component will limit the turbine regulating steam valve from opening further to ensure that the actual main steam pressure Pt changes within the allowable range; S14: The steam pressure deviation signal Ps-Pt is simultaneously sent to the boiler controller to adjust the boiler to supplement the additional fuel amount caused by the change in boiler heat storage due to the change in steam pressure; S15: When the adjustment is finished, the equilibrium state of P0=PE and Pt=Ps is reached; Where P0: unit load instruction; Ps: main steam pressure setting value of the unit; PE: actual load of the unit; Pt: actual main steam pressure; BID: boiler input instruction; The load command of the boiler-machine coordination mode is generated by the load command generation loop, a load rate function is constructed and the smaller of the value set by the operator is taken, and the automatic speed reduction in the high load section is realized through the automatically generated load command; The adjustment steps of the boiler main controller in S2 are: S21: Modify the load-coal quantity function; S22: Separate the dynamic and static parameters of the boiler master regulator; S23: After the load change is over, there is a delay of 60 seconds and the boiler master control switches from dynamic parameters to static parameters; S24: When the steam turbine master control is in manual mode, the boiler master control is automatically switched to manual mode; S25: Add boiler master control lockout conditions; S3: During power closed-loop control, the steam turbine uses dynamic load forward feedback to achieve rapid response of the turbine dynamic process, so that the output of the steam turbine unit is compatible with the grid load requirements; S4: The feedforward signal of the boiler main controller corrects the fuel calorific value in the boiler in real time through the fuel correction loop to achieve a balance between energy supply and demand between the boiler and the turbine.

2. A generator set coordinated control method according to claim 1, characterized in that: In S3, when the dynamic process of the steam turbine is being rapidly responded to, the main steam pressure in the pressure pull-back loop function is first modified, and then the third-order inertia of the steam turbine command is cancelled in the AGC mode, and the AGC mode load grabbing loop is added.

3. A generator set coordinated control method according to claim 2, characterized in that: The steps of generating the main steam pressure through the main steam pressure setting generation circuit are as follows: S31: Because the primary frequency modulation is a transient mode, the influence of the primary frequency modulation on the main steam pressure setting is eliminated; S32: Change the pressure setting from third-order inertia to first-order inertia, and the inertia time is 150s; S33: Modify the sliding pressure rate curve under normal working conditions.

4. A generator set coordinated control method according to claim 3, characterized in that: In S4, the adjustment steps of the fuel correction circuit are: S41: Construct a BTU automatic regulator, set the theoretical fuel quantity under the current load according to the unit load setting or the actual power, compare it with the corrected fuel quantity after BTU correction, enter the PID regulator to adjust the BTU output coefficient, and its control dead zone is ±4t / h; S42: BTU output is a coefficient, its physical meaning = designed fuel quantity / actual fuel quantity, adjustable range is 0.8-1.2; S43: The fuel calibration circuit has two modes: manual and automatic; S44: When any of the following situations occurs: unit load change, coal mill start / stop within 5 minutes, power deviation exceeds 10MW, or main steam pressure deviation exceeds 1MPa, BTU regulation maintains the current output in automatic state; S45: When the fuel master control is manual or the unit load is less than 300MW, the BTU adjustment is switched to manual mode.

5. A generator set coordinated control method according to claim 4, characterized in that: In the above S42, when BTU is less than 1, the actual coal consumption is greater than the designed coal consumption; when BTU is greater than 1, the actual coal consumption is less than the designed coal consumption.

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