CN116500949A - Coordinated control method for generator set - Google Patents
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Abstract
The invention discloses a coordinated control method of a generator set, which comprises the following steps: s1: the boiler and the steam turbine are operated in a fixed-sliding-fixed pressure mode in a machine-furnace coordination mode; s2: the machine-furnace coordination mode sends power deviation signals P0-PE to a steam turbine controller to form power closed-loop control, and meanwhile, the power deviation signals are added to a nonlinear link and a feedforward signal P0 to form a feedforward signal of a main controller of the boiler; s3: during power closed-loop control, the steam turbine adopts a dynamic load front feedback mode to realize the quick response of the dynamic process of the steam turbine; s4: the feedforward signal of the boiler main controller corrects the heat value of the fuel in the boiler in real time through the fuel correction loop. The invention provides a coordinated control method of a generator set, which can realize the quick response of a dynamic process of a steam turbine in a machine-furnace coordination mode when the coordinated control is implemented; the output of the turbine unit is adapted to the load requirement of the power grid, and the balance relation between the two energy supply and demand is reasonably maintained.
Description
Technical Field
The invention relates to the field of thermal generator sets, in particular to the field of a coordinated control system of a generator set.
Background
The proportion of the thermal generator set in the power grid is larger and larger, and the power grid is changed in power utilization structure, so that the peak-valley difference of the load is gradually increased, and the large-sized generator set is required to have the capacity of running with variable load, so that the requirement of load change is met rapidly, and the frequency modulation of the power grid is participated; whether the output electric power of the thermal power unit is consistent with the load requirement reflects the balance relation of energy supply and demand between the unit and an external power grid, the main steam pressure reflects the balance relation of energy supply and demand between a boiler inside the unit and a turbine generator, and a coordination control system is arranged for completing the two balance relations; when the coordination control system operates, the boiler, the steam turbine and the generator with large difference in dynamic characteristics are used as a unified whole for controlling, and the organic and coordinated control of the fuel, the air supply, the induced air and the water supply of the boiler and the opening of the steam turbine regulating door can minimize the influence among variables; most of the building debugging periods have the problems of short debugging time and insufficient debugging depth; the problem that the load tracking is slow after the unit is put into operation and can not adapt to various working conditions is caused.
Disclosure of Invention
The invention aims to: in order to overcome the defects in the prior art, the invention provides a coordinated control method of a generator set, which can realize the quick response of the dynamic process of a steam turbine in a machine-furnace coordination mode when the coordinated control is implemented; the output of the turbine unit is adapted to the load requirement of the power grid, and the balance relation between the two energy supply and demand is reasonably maintained.
The technical scheme is as follows: in order to achieve the above purpose, the technical scheme of the invention is as follows:
a coordinated control method of a generator set comprises the following steps:
s1: the boiler and the steam turbine are operated in a fixed-sliding-fixed pressure mode in a machine-furnace coordination mode;
s2: the machine-furnace coordination mode sends power deviation signals P0-PE to a steam turbine controller to form power closed-loop control, and meanwhile, the power deviation signals are added to a nonlinear link and a feedforward signal P0 to form a feedforward signal of a main controller of the boiler;
s3: during power closed-loop control, the steam turbine adopts a dynamic load front feedback mode to realize the quick response of the dynamic process of the steam turbine, so that the output of the steam turbine unit is adapted to the load requirement of a power grid;
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 so as to achieve the balance of energy supply and demand between the boiler and the steam turbine.
Further, in the step S2, the adjusting step of the machine-furnace coordination mode is as follows:
s11: setting a load instruction P0 to increase, sending a power instruction signal P0 into a steam turbine controller and a boiler controller in parallel, enabling the steam turbine controller to rapidly open a steam turbine regulating steam valve, reducing the pressure Pt in front of the steam turbine, discharging heat from the boiler, and increasing the steam flow so as to adapt to the load increasing requirement;
s12: according to the load change rate set by the unit, a load instruction P0 is adopted as a feedforward signal sent to the boiler so as to compensate inertia and delay of the boiler;
s13: when the steam pressure deviation |Ps-Pt| is not less than the delta of the dead zone component, the dead zone component can limit the regulating steam valve of the steam turbine to be continuously opened;
s14: the steam pressure deviation signal Ps-Pt is simultaneously sent to a boiler controller to regulate the boiler so as to supplement the additional fuel quantity for the heat accumulation change of the boiler caused by the steam pressure change;
s15: at the end of the adjustment, an equilibrium state of p0=pe, pt=p0 is reached.
Further, a load instruction of a machine-furnace coordination mode is generated through a load instruction generation loop, a load rate function and an operator set value are constructed to be small, and automatic deceleration of a high load section is realized through the automatically generated load instruction.
Further, the step of adjusting the main controller of the boiler in S2:
s21: modifying the load-coal quantity function;
s22: the parameters of a main control regulator of the boiler are dynamically and statically separated;
s23: delaying for 60s after the load change is finished, and switching the main control of the boiler from a dynamic parameter to a static parameter;
s24: when the main control of the steam turbine is manual, the main control of the boiler is automatically cut into a manual state;
s25: and increasing the main control locking condition of the boiler.
Further, in the step S3, when the quick response of the dynamic process of the steam turbine is performed, the main steam pressure in the pressure pull loop function is modified first, then the third-order inertia of the steam turbine instruction is cancelled in the AGC mode, and the load loop is increased in the AGC mode.
Further, the step of generating the main steam pressure by the main steam pressure setting generation circuit comprises the following steps:
s31: the influence of the primary frequency modulation on the main steam pressure setting is removed because the primary frequency modulation is in a transient mode;
s32: changing the pressure setting third-order inertia into first-order inertia, wherein the inertia time is 150s;
s33: and modifying the normal working condition sliding pressure rate curve.
Further, in the step S4, the adjusting step of the fuel correction circuit is as follows:
s41: constructing a BTU automatic regulator, setting theoretical fuel quantity under the current load according to unit load or actual power, comparing the theoretical fuel quantity with corrected fuel quantity corrected by the BTU, and entering a PID regulator to regulate the BTU output coefficient, wherein the dead zone is controlled to be +/-4 t/h;
s42: BTU output is a coefficient with physical meaning = design fuel amount/actual fuel amount, adjustable range of 0.8-1.2;
s43: the fuel correction loop has two modes of manual operation and automatic operation;
s44: when any condition that the load of the unit is changed, the power deviation exceeds 10MW or the main steam pressure deviation exceeds 1MPa occurs within 5 minutes after the start/stop of the coal mill, the BTU regulation keeps the current output in an automatic state;
s45: when the fuel master is manual or the unit load is less than 300MW, the BTU adjustment is switched to a manual mode.
Further, in the step S42, when BTU is less than 1, the actual consumed coal amount is larger than the designed coal amount; when BTU > 1, the actual fuel consumption is less than the design fuel consumption.
The beneficial effects are that: according to the invention, the load instruction of the unit is directly sent to the main controller of the boiler and the steam turbine, so that the unit can obtain faster load correspondence, and meanwhile, the power correction and the pressure correction loop before the unit are used as hysteresis correction in load change, so that the unit can accurately control the power and the pressure; when the power generator set is in coordination control, the steam turbine adopts a dynamic load front feedback mode to realize the quick response of the dynamic process of the steam turbine, so that the output of the steam turbine set is adapted to the load requirement of a power grid, the feedforward signal of the boiler main controller corrects the fuel calorific value in the boiler in real time through the fuel correction loop so as to achieve the balance of energy supply and demand between the boiler and the steam turbine, and further, the actions on two sides of the boiler can be well coordinated, and the balance relation between the two energy supply and demand is reasonably kept so as to take account of the load response performance and the stability of internal operation parameters; the adjusting quality of main operation parameters of the unit is improved, the output of the unit is adapted to the load requirement of the power grid, and the requirement of quick response AGC of the unit is met.
Drawings
FIG. 1 is a step diagram of a coordinated control method of a generator set;
FIG. 2 is a schematic block diagram of a generator set load control object;
FIG. 3 is a block diagram of the coordinated control logic of the unit.
Detailed Description
The invention will be further described with reference to the accompanying drawings.
As shown in fig. 1-3: a coordinated control method of a generator set comprises the following steps:
s1: the boiler and the steam turbine are operated in a fixed-sliding-fixed pressure mode in a machine-furnace coordination mode;
s2: the machine-furnace coordination mode sends power deviation signals P0-PE to a steam turbine controller to form power closed-loop control, and meanwhile, the power deviation signals are added to a nonlinear link and a feedforward signal P0 to form a feedforward signal of a main controller of the boiler;
s3: during power closed-loop control, the steam turbine adopts a dynamic load front feedback mode to realize the quick response of the dynamic process of the steam turbine, so that the output of the steam turbine unit is adapted to the load requirement of a power grid;
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 so as to achieve the balance of energy supply and demand between the boiler and the steam turbine.
The generator set boiler and the steam turbine are two relatively independent devices; from the point of view of the control of the load of the power plant, the power plant is a control object with a plurality of variables associated with each other, which can be considered as a controlled object with two inputs and two outputs, through appropriate assumptions, as shown in fig. 2; wherein TD = turbine master command; μt = turbine regulator valve opening; PE = unit load; BD = boiler master command; μb=boiler firing rate and corresponding water supply; pt = pre-machine pressure.
According to thermodynamic system characteristics, the dynamic characteristics of the load control object can be known to be: when the opening degree of the valve of the steam turbine acts, the response of the controlled quantity PE and Pt is quick, namely the thermal inertia is small; when the boiler combustion rate is changed, the response of PE and Pt is very slow, namely the thermal inertia is large, and the speed is the larger difference in the aspect of the dynamic characteristics of the engine-furnace object, so that the two energy supply-demand relations inside the generator set are mutually restricted, and the inherent contradiction exists between the external load response performance and the internal operation parameter stability. According to the characteristics, when the generator set performs coordination control, the actions of two sides of the generator furnace are well coordinated, and the two energy supply and demand balance relations are reasonably kept, so that the two aspects of load response performance and internal operation parameter stability are considered.
The machine-furnace coordination control system of the machine unit consists of a machine-furnace coordination mode (CCS), a boiler tracking mode (BF), a steam turbine tracking mode (TF) and a basic mode (BH); when the unit normally operates, a machine-furnace coordination mode is generally adopted, and the unit operates according to a fixed-sliding-fixed pressure mode.
Furnace coordination mode CCS: the boiler-turbine generator set is controlled as a whole, the boiler and the turbine are coordinated through a control loop to operate in an automatic state to give out instructions to an automatic control system of the boiler and the turbine so as to adapt to the requirement of load change, the frequency modulation and peak regulation capacity of the generator set is exerted to the greatest extent, and the execution stage of the direct action of the generator set is a boiler fuel control system and a turbine control system; boiler tracking mode BF: the control mode is a control mode for controlling the power of the steam turbine and controlling the steam pressure of the boiler so as to adapt the load of the boiler to the load change of the steam turbine; steam turbine tracking mode TF: according to the requirement of the grid load, directly controlling the fuel quantity B of the boiler by a power regulator; as the input heat of the boiler is increased or reduced, the main steam pressure pt is changed, at the moment, the main steam pressure regulator continuously changes the opening degree of the steam regulating valve to maintain the main steam pressure to be stable, and the opening or closing of the steam regulating valve means the change of the output of the unit, so that the requirement of the power grid load is met; when the unit normally operates, a machine-furnace coordination mode is generally adopted, and the unit operates according to a fixed-sliding-fixed pressure mode; basic mode BH: in multiple tests, it is important to control the probability of making a first type of error. Bonferroni has proposed a/m as the a value for each sub-test; however, this correction method has the disadvantage of being too conservative. For example, in comparing whether there is a difference between 10 groups,let a=0.05, then the value of α for each test is +.>So the original hypothesis is rejected little or no; thus, benjamini and Hochberg propose a new method to control the accuracy of the test by controlling the size of the FDR.
From the research of the dynamic characteristics of the generator set object, the main operating parameters of the generator set, namely the generator set power under the respective action of the control means at the two sides of the generator set and the furnace, have great difference in the dynamic characteristics of the main steam pressure. The starting point of the design of the generator-furnace coordination control system of the generator set is that the quick load response of the generator set and the necessary stability of main operation parameters of the generator set must be considered simultaneously. In view of this, the basic control strategy of the machine-oven coordinated control system is: the control speed of the boiler combustion rate is accelerated as much as possible, and the stability of the boiler is properly sacrificed so as to meet the real-time requirement of power.
The control system optimizes the load change condition of the front unit:
1) Under the working condition that the change rate of the unit is set to 9MW/min, the load response is slower, the actual rate is about 5MW/min, the fluctuation of the intermediate point temperature and the main steam temperature reheat steam temperature is larger, the water cooling wall is easy to be over-heated, and the requirements of fast response load and stable operation of the unit cannot be well met.
2) The feed-forward of the unit becomes a constant variable load quantity, is only related to the variable load rate, and cannot be automatically adjusted according to different working conditions such as load, pressure and the like, so that the press furnace is unbalanced in the continuous load change process.
3) The fuel correction circuit is not in operation. The coal quality of the current unit operation is changed in a test operation period and has certain fluctuation; the original control logic does not correct the main steam pressure, the main steam temperature, the main steam superheat degree and other important parameters under the condition of coal quality change.
4) The main control of the boiler is not separated in dynamic and static state. In 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 main control adopts single parameter, is not distinguished from dynamic and static distinction, and is easy to cause the condition of overshoot of dynamic process and undershoot of static process.
According to the field situation, the coordinated control thought of the machine and the furnace of the machine set is as follows:
1) When the load of the unit changes, the response speed of the boiler is accelerated through the change of primary air, the pressure of the main steam is allowed to change slightly, and after the load is stabilized, the pressure of the main steam is regulated by the combustion rate of the boiler. Therefore, the control effect is achieved, the load response requirement of the unit is met in the process of changing the power of the unit, and meanwhile, the stability of the main steam pressure and other main operation parameters of the unit is ensured, and the dynamic and static deviations of the main steam pressure are smaller. Therefore, the unit optimizing control strategy adopts a coordination control mode mainly comprising furnace following. The load instruction of the unit is directly sent to the main controller of the boiler and the steam turbine, so that the unit can obtain faster load correspondence, and meanwhile, a power correction loop and a pre-machine pressure correction loop are used as hysteresis correction in load change, so that the unit can accurately control power and pressure; the optimized control strategy is shown in fig. 3.
In the step S2, the adjustment steps of the machine-furnace coordination mode are as follows: wherein P0: a unit load instruction; ps: a set main steam pressure set point; PE: actual load of the unit; pt: actual main steam pressure; BID: inputting an instruction by a boiler;
s11: setting a load instruction P0 to increase, sending a power instruction signal P0 into a steam turbine controller and a boiler controller in parallel, enabling the steam turbine controller to rapidly open a steam turbine regulating steam valve, reducing the pressure Pt in front of the steam turbine, discharging heat from the boiler, and increasing the steam flow so as to adapt to the load increasing requirement;
s12: because the response of the boiler to the load change is slower than that of the steam turbine, according to the load change rate set by the unit, a load instruction P0 is adopted as a feedforward signal sent to the boiler to compensate the inertia and delay of the boiler; meanwhile, the integral link of the main controller of the boiler carries out closed-loop correction on the pressure in front of the engine, so as to achieve the aim of accurately controlling the pressure of the main steam;
s13: if the rate and magnitude of load demand increase is large, the magnitude of change in the vapor pressure Pt may be caused to be excessively large; when the steam pressure deviation |Ps-Pt| is not less than the delta of the dead zone component, the dead zone component can limit the regulating steam valve of the steam turbine to be continuously opened; to ensure that the vapor pressure Pt varies within an allowable range;
s14: the steam pressure deviation signal Ps-Pt is simultaneously sent to a boiler controller, so that the regulation effect on the boiler is enhanced, and the additional fuel quantity caused by the change of the heat storage capacity of the boiler due to the change of the steam pressure is supplemented;
s15: at the end of the adjustment, an equilibrium state of p0=pe, pt=p0 is reached. The system is characterized by being capable of compensating inertia and delay of the boiler and enhancing the control function of the boiler.
In order to realize quick response of a dynamic process of the unit, the unit is realized by adopting a dynamic variable load feedforward mode in consideration of relatively large delay and inertia of the boiler and subsystems thereof. The feedforward quantity is automatically adjusted according to the current load, pressure, load span and change rate so as to adapt to the change requirements of various working conditions of the boiler; the loop is respectively applied to related sub-loops such as fuel, water supply, superheat degree, desuperheating water, primary air, air supply, induced air, denitration and the like; the fuel correction loop (BTU) is optimized to adapt to the coal quality change, and the real-time response of the unit load is ensured.
The load instruction of the machine-furnace coordination mode is generated by a load instruction generating loop; the load change rate is automatically limited. Considering that the output of the coal mill in the high load section approaches the limit, the powder discharging speed is obviously slowed down, the inertia of the boiler is obviously increased, and in order to ensure the safety of the unit and the non-overpressure of the boiler, a load rate function and a set value of an operator are constructed to be smaller, and the automatic deceleration of the high load section is realized through an automatically generated load instruction; as in table 1.
TABLE 1 load-Rate function table for units
| Load instruction (MW) | Variable load rate (MW/min) |
| 0 | 18 |
| 500 | 18 |
| 590 | 18 |
| 600 | 12 |
| 610 | 9 |
| 660 | 6 |
And in the step S2, the main controller of the boiler is adjusted:
s21: modifying the load-coal quantity function to ensure the accuracy of load linear feedforward;
s22: the parameters of a main control regulator of the boiler are dynamically and statically separated; under static state, the proportion, integration and differentiation effects are enhanced, the pressure stability of the main steam is ensured, and the energy balance between the boiler and the steam turbine is ensured; under the dynamic state, the proportion, integral and differential actions are weakened, and overshoot of the main control of the boiler caused by pressure lag is avoided;
s23: delaying for 60s after the load change is finished, and switching the main control of the boiler from a dynamic parameter to a static parameter;
s24: when the main control of the steam turbine is manual, the main control of the boiler is automatically cut into a manual state;
s25: and the main control locking condition of the boiler is increased, so that the main control integral saturation of the boiler caused by the out-of-force overrun of the factor loop is avoided.
Table 2 boiler load-linear function table
| Load instruction (MW) | Coal quantity (t/h) |
| 0 | 0 |
| 211.2 | 85 |
| 264 | 101 |
| 330 | 125.6 |
| 495 | 190 |
| 660 | 260 |
| 700 | 263.3 |
TABLE 3 master control lockout condition for boilers
In the step S3, when the quick response of the dynamic process of the steam turbine is carried out, the main steam pressure in the pressure pull-back loop functions (such as tables 4 and 5) is modified, and when the high pressure section is overpressurized, the pull-back loop function is enhanced, so that the safety of the unit is ensured; the other conditions weaken the action of a pull-back loop, and ensure the accuracy of load adjustment; then, under the AGC mode, canceling the third-order inertia of the steam turbine instruction, and reducing the load response time; adding an AGC mode load-robbing loop; in the AGC mode, when the load is increased, the load instruction of the steam turbine is increased by 2MW, so that the load response rate is improved; when the load change is over, the 2MW additional command disappears. The automatic power generation control AGC (Automatic Generation Control) is an important function in the energy management system EMS, and controls the output force of the frequency modulation unit to meet the continuously changing power requirements of users and enable the system to be in an economic running state;
table 4 pull-back loop function table for steam engine
| Pressure deviation P V-SP (MPa) | Power (MW) |
| -2 | -8 |
| -1 | -2 |
| -0.5 | 0 |
| 0.5 | 0 |
| 1 | 2 |
| 2 | 8 |
Table 5 correction function table for pull-back loop of steam turbine
| Main steam pressure (M Pa) | Gain of |
| 0 | 1 |
| 10 | 1 |
| 20 | 1 |
| 24 | 1 |
| 25 | 3 |
| 26 | 5 |
The main steam pressure is generated by the main steam pressure setting generation loop through the steps of:
s31: the influence of the primary frequency modulation on the main steam pressure setting is removed because the primary frequency modulation is in a transient mode;
s32: changing the pressure setting third-order inertia into first-order inertia, wherein the inertia time is 150s;
s33: the normal operating mode slip pressure rate curve is modified (as in table 6).
TABLE 6 Main steam pressure set sliding pressure Rate Curve
| 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 |
A boiler variable load feedforward control loop; in order to accelerate the response speed of the boiler and meet the AGC requirement, the variable load feedforward loop is re-constructed, so that the energy of the boiler is controlled in advance, and the inertia of the system is reduced. The feedforward quantity is automatically adjusted according to the current load, pressure, load span and change rate so as to adapt to the change requirements of various working conditions of the boiler; the loop is respectively applied to related sub-loops such as fuel, water supply, superheat degree, temperature reduction water, primary air, air supply, induced air, denitration and the like.
The main control regulation and fuel setting of the boiler of the unit are based on the design of coal types, and the sub-loops of water, coal, wind and the like are mutually coordinated by regulating the heat of entering the boiler, so that the purposes of accurately controlling the energy output and matching with the requirements of a steam turbine are achieved. Therefore, when the change of the coal quality of the entering furnace is large, the reference point for adjusting the main control coal quantity of the boiler is deviated from the original value, so that the fluctuation of the main steam pressure and the steam temperature is large, and meanwhile, the ratio of water coal to wind coal is close to the limit value, and the adjustment margin is not provided. Therefore, the fuel calorific value needs to be corrected in real time, so that the control datum point of the boiler energy is unchanged, and the self-adaptive adjustment under the fluctuation of the coal quality is realized. In light of the above, fuel correction circuits (BTUs) have been redesigned to achieve this function.
In the step S4, the adjusting step of the fuel correction circuit is as follows:
s41: constructing a BTU automatic regulator, setting theoretical fuel quantity under the current load according to unit load or actual power, comparing the theoretical fuel quantity with corrected fuel quantity corrected by the BTU, and entering a PID regulator to regulate the BTU output coefficient, wherein the dead zone is controlled to be +/-4 t/h;
s42: BTU output is a coefficient with physical meaning = design fuel amount/actual fuel amount, adjustable range of 0.8-1.2; when BTU is less than 1, the actual coal type is worse, and the actual consumption coal amount is larger than the design coal amount; when BTU is more than 1, the actual coal type is better, and the actual consumption coal amount is smaller than the design coal amount;
s43: the fuel correction loop has two modes of manual operation and automatic operation; under normal conditions, the BTU loop automatically adjusts to accommodate slow changes in coal quality; when the coal quality is changed severely or the abnormal working condition occurs and the coal quantity needs to be changed rapidly, the loop can be switched to a manual mode for manual addition and subtraction; when the BTU output is increased (decreased) by 0.01, the actual coal amount is decreased (increased) by 1% of the current coal amount.
S44: when any condition that the power deviation exceeds 10MW or the main steam pressure deviation exceeds 1MPa occurs within 5 minutes after the unit is subjected to load change and the coal mill is started/stopped, the BTU regulation keeps the current output in an automatic state, and the influence of system disturbance on the regulation is avoided;
s45: when the fuel master is manual or the unit load is less than 300MW, the BTU adjustment is switched to a manual mode.
After the coordinated control system of the unit works, under the condition of ensuring that the main steam pressure, the main reheat steam temperature and other parameters are stable, the load can be quickly increased and decreased, the actual change rate of the load reaches more than 1.3% Pe/min, the adjustment quality of main operation parameters of the unit is improved, the output of the unit is adapted to the load requirement of a power grid, and the requirement of quick response AGC of the unit is met.
The above description is only of the preferred embodiments of the present invention and is not intended to limit the present invention, and it is apparent to those skilled in the art that modifications and variations can be made without departing from the above-described principle of the present invention, and these modifications and variations are also regarded as the scope of the invention.
Claims (8)
1. The coordinated control method of the generator set is characterized by comprising the following steps of:
s1: the boiler and the steam turbine are operated in a fixed-sliding-fixed pressure mode in a machine-furnace coordination mode;
s2: the machine-furnace coordination mode sends power deviation signals P0-PE to a steam turbine controller to form power closed-loop control, and meanwhile, the power deviation signals are added to a nonlinear link and a feedforward signal P0 to form a feedforward signal of a main controller of the boiler;
s3: during power closed-loop control, the steam turbine adopts a dynamic load front feedback mode to realize the quick response of the dynamic process of the steam turbine, so that the output of the steam turbine unit is adapted to the load requirement of a power grid;
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 so as to achieve the balance of energy supply and demand between the boiler and the steam turbine.
2. The coordinated control method of a generator set according to claim 1, characterized in that: in the step S2, the adjustment steps of the machine-furnace coordination mode are as follows:
s11: setting a load instruction P0 to increase, sending a power instruction signal P0 into a steam turbine controller and a boiler controller in parallel, enabling the steam turbine controller to rapidly open a steam turbine regulating steam valve, reducing the pressure Pt in front of the steam turbine, discharging heat from the boiler, and increasing the steam flow so as to adapt to the load increasing requirement;
s12: according to the load change rate set by the unit, a load instruction P0 is adopted as a feedforward signal sent to the boiler so as to compensate inertia and delay of the boiler;
s13: when the steam pressure deviation |Ps-Pt| is not less than the delta of the dead zone component, the dead zone component can limit the regulating steam valve of the steam turbine to be continuously opened;
s14: the steam pressure deviation signal Ps-Pt is simultaneously sent to a boiler controller to regulate the boiler so as to supplement the additional fuel quantity for the heat accumulation change of the boiler caused by the steam pressure change;
s15: at the end of the adjustment, an equilibrium state of p0=pe, pt=p0 is reached.
3. The coordinated control method of a generator set according to claim 2, characterized in that: the load instruction of the machine-furnace coordination mode is generated through a load instruction generation loop, a load rate function and an operator set value are constructed to be small, and the automatic deceleration of a high-load section is realized through the automatically generated load instruction.
4. A method of coordinated control of a generator set according to claim 3, wherein: and in the step S2, the main controller of the boiler is adjusted:
s21: modifying the load-coal quantity function;
s22: the parameters of a main control regulator of the boiler are dynamically and statically separated;
s23: delaying for 60s after the load change is finished, and switching the main control of the boiler from a dynamic parameter to a static parameter;
s24: when the main control of the steam turbine is manual, the main control of the boiler is automatically cut into a manual state;
s25: and increasing the main control locking condition of the boiler.
5. The coordinated control method of a generator set according to claim 4, wherein: in the step S3, when the quick response of the dynamic process of the steam turbine is carried out, the main steam pressure in the pressure pull loop function is modified, then the third-order inertia of the steam turbine instruction is canceled in the AGC mode, and the load loop is increased in the AGC mode.
6. The coordinated control method of a generator set according to claim 5, wherein: the main steam pressure is generated by the main steam pressure setting generation loop through the steps of:
s31: the influence of the primary frequency modulation on the main steam pressure setting is removed because the primary frequency modulation is in a transient mode;
s32: changing the pressure setting third-order inertia into first-order inertia, wherein the inertia time is 150s;
s33: and modifying the normal working condition sliding pressure rate curve.
7. The coordinated control method of a generator set according to claim 6, wherein: in the step S4, the adjusting step of the fuel correction circuit is as follows:
s41: constructing a BTU automatic regulator, setting theoretical fuel quantity under the current load according to unit load or actual power, comparing the theoretical fuel quantity with corrected fuel quantity corrected by the BTU, and entering a PID regulator to regulate the BTU output coefficient, wherein the dead zone is controlled to be +/-4 t/h;
s42: BTU output is a coefficient with physical meaning = design fuel amount/actual fuel amount, adjustable range of 0.8-1.2;
s43: the fuel correction loop has two modes of manual operation and automatic operation;
s44: when any condition that the load of the unit is changed, the power deviation exceeds 10MW or the main steam pressure deviation exceeds 1MPa occurs within 5 minutes after the start/stop of the coal mill, the BTU regulation keeps the current output in an automatic state;
s45: when the fuel master is manual or the unit load is less than 300MW, the BTU adjustment is switched to a manual mode.
8. The coordinated control method of a generator set according to claim 7, wherein: in the step S42, when the BTU is less than 1, the actual consumed coal amount is larger than the designed coal amount; when BTU > 1, the actual fuel consumption is less than the design fuel consumption.
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