Summary of the invention
At the problems referred to above, the purpose of this invention is to provide a kind of coal-fired value real time monitoring method of fired power generating unit and value observer that is applied to automation field.
For achieving the above object, the present invention takes following technical scheme: the coal-fired value real time monitoring method of a kind of fired power generating unit, it may further comprise the steps: 1) based on the dynamic perfromance of fired power generating unit, the uses energy law of conservation is set up value observer, and described value observer comprises two parts of unit model and calorific value corrective loop; 2) in the DCS control system, search the actual motion unit under design coal during stable operation, corresponding relation under the different load between each operational factor, described operational factor comprise coal amount, steam turbine pitch aperture, unit load, first class pressure, the preceding pressure of machine, drum or separator outlet pressure and main steam flow; 3) by step 2) described in the probability statistics of operational factor of actual motion unit each parameter in the described unit model is carried out static configuration, make the static output parameter of described unit model under each load section can be good at embodying the characteristic of described actual motion unit operation parameter; 4) rule of thumb value provides between the inertial time of inertial element in the described unit model and the integral time of integrator; 5) operational factor of parameter of in unit operation described unit model being calculated and described actual motion unit compares analysis, and according to the result of comparative analysis each parameter in the described unit model is made amendment, make the dynamic output parameter of described unit model under each load section also can be good at embodying the characteristic of described actual motion unit operation parameter; 6) open calorific value calculation function in the described value observer, allow the stable operation under different coals of described actual motion unit, and the function dead band in the described unit model parameter configuration is provided with to eliminate unit parameter self fluctuation and the principle that is changed to that takes place of reflection unit actual energy among a small circle, check the corresponding situation of calorific value of calorific value that described value observer calculates and described actual motion unit coal then, the parameter of revising in the described calorific value corrective loop makes it to be complementary with actual conditions; 7) pressure, first class pressure are input to step 1)~6 before drum that the coal amount signal of in-site measurement and unit is present or separator outlet pressure, the machine) the described value observer set up, calorific value calculation module in described value observer draws the calorific value corrected parameter after calculating, and the coal amount signal of described calorific value corrected parameter correction in-site measurement obtains the coal amount signal of standard.
In execution in step 5) time, if the final numerical value of each parameter is the same with the operational factor of described actual motion unit in the described unit model, just and the operational factor of described actual motion unit individual mistiming is arranged, then change between the inertial time of corresponding inertial element integral time with integrator.
In execution in step 5) time, if the operational factor of the final numerical value of each parameter and described actual motion unit is different in the described unit model, then revise corresponding function generator.
A kind of coal-fired value observer of fired power generating unit of realizing said method, it is characterized in that: it comprises a unit model, described unit model comprises first to the 6th function generator, the input end of described first function generator connects first multiplier, its output terminal connects the positive input terminal of first subtracter after through four inertial elements, an input end of described first multiplier connects described calorific value corrective loop, and another input end is the coal amount; The merit of described first function generator is exactly the coal amount that enters boiler to be converted to corresponding main steam flow and four the following inertial element analog fuels that enter boiler enter boiler combustion characteristics to drum or this section of separator inlet boiler through pressurization is heated in burning to feedwater after; The input end of described second function generator connects the output terminal of second subtracter, its output terminal connects the negative input end of described first subtracter and the positive input terminal of the 3rd subtracter respectively, the output terminal of described first subtracter connects first integrator, the output terminal of described first integrator connects the positive input terminal of described second subtracter, the output terminal of described the 3rd subtracter connects the second integral device, and the output terminal of described second integral device connects the negative input end of described second subtracter respectively; The function of described second function generator be simulation from drum or separator outlet to steam turbine this interval pressure one discharge characteristic of superheater bringing-up section of boiler the inlet; The input end of described the 3rd function generator connects described second integral device output terminal, and its output terminal connects the input end of second multiplier, and the output terminal of described second multiplier connects the negative input end of described the 3rd subtracter; The function of described the 3rd function generator is that the simulation main steam enters the variation characteristic of steam turbine to this section of steam turbine speed control porthole steam turbine acting main steam flow; The output terminal of described the 4th function generator connects described second multiplier input, and its input end is a steam turbine pitch aperture, and the function of described the 4th function generator is the influence of simulation steam turbine pitch to main steam flow; The input end of described the 5th function generator connects the output terminal of described second multiplier, and its output terminal connects described the 6th function generator behind an inertial element, and described the 6th function generator connects an inertial element; The input variable of described the 5th function generator is the main steam flow behind the steam turbine pitch, and its output is first class pressure behind inertial element; The input variable of described the 6th function generator is a first class pressure, and its output is unit load behind an inertial element.
On described unit model, connect a calorific value corrective loop, described calorific value corrective loop comprises the 7th to the tenth function generator, the input end of described the 7th function generator connects the output terminal of the 4th subtracter, its output terminal connects first adder, the negative input end of described the 4th subtracter connects the output terminal of described first integrator, and its positive input terminal is actual drum or separator outlet pressure; The deviation that the input variable of described the 7th function generator calculates through described the 4th subtracter for drum or separator outlet pressure in actual drum or separator outlet pressure and the unit model, it is output as the influence of pressure divergence to the boiler fired coal calorific value; The input end of described the 8th function generator connects the output terminal of the 5th subtracter, and its output terminal connects described first adder, and the negative input end of described the 5th subtracter connects the output terminal of described second integral device, and its positive input terminal is a pressure before the actual machine; The input variable of described the 8th function generator is the deviation that pressure calculates through described the 5th subtracter before the machine in preceding pressure of actual machine and the unit model, and it is output as the influence of pressure divergence to the boiler fired coal calorific value; The input end of described the 9th function generator connects the output terminal of the 6th subtracter, its output terminal connects the third integral device, the negative input end of described the 6th subtracter connects the input end of described the 6th function generator, its positive output end is actual first class pressure, and the output terminal of described third integral device connects the input end of second adder; The deviation that the input variable of described the 9th function generator calculates through described the 6th subtracter for first class pressure in actual first class pressure and the unit model, its output calculates the basic value of ature of coal calorific value through described third integral device; The input end of described the tenth function generator connects the output terminal of described first adder, its output terminal connects the input end of described second adder, the output terminal of described second adder connects the N end of a handoff block, the Y end of described handoff block is present calorific value signal, and the output terminal of described handoff block connects the input end of described first multiplier; The input variable of described function generator be before drum or separator outlet pressure and the machine before the drum in pressure and the unit model or separator outlet pressure and the machine deviation of pressure after little deviation excision with, it represents not the matching of energy signal of boiler side steam.
Described the 7th function generator and the 8th function generator are functions that has little deviation excision.
Adopt a calorific value to proofread and correct the switching signal of the pulse signal of input as described handoff block.
The present invention is owing to take above technical scheme, it has the following advantages: 1, value observer of the present invention is based on that the dynamic perfromance of fired power generating unit sets up, the parameter of considering for unit is more comprehensive, therefore can very comprehensively estimate out the present combustion case of unit, calculate near actual coal-fired calorific value.2, value observer of the present invention is based on that the dynamic perfromance of fired power generating unit sets up, and on parameter setting, each parameter in the unit model is relatively independent, and therefore very big dirigibility is arranged on parameter is provided with.3, value observer of the present invention is based on that the dynamic perfromance of fired power generating unit sets up, and can calculate the present coal-fired calorific value of unit faster, to the variation monitoring response speed of ature of coal than very fast.4, the present invention can be in the situation of power plant's on-line real time monitoring ature of coal in service, and this situation is fed back in the control system of power plant, makes unit to safely and steadily run, and can avoid causing the over-temp and over-pressure of unit owing to ature of coal has greatly changed.
Embodiment
Below in conjunction with drawings and Examples the present invention is described in detail.
As shown in Figure 2, value observer of the present invention is based on the dynamic perfromance of fired power generating unit, and the uses energy law of conservation is set up, and it comprises two parts of unit model and calorific value corrective loop.Unit model comprises one group of function generator 1~6, and the input end of function generator 1 connects a multiplier a, its output terminal through four inertial elements after input subtracter a+input end.The input end of multiplier a connects the calorific value corrective loop, and another input end is the coal amount.The entry variable of function generator 1 is the coal amount after superheat value is proofreaied and correct, reference variable-main steam flow in the middle of it is output as, its function is exactly the coal amount that enters boiler to be converted to corresponding main steam flow and four the following inertial element analog fuels that enter boiler enter boiler combustion characteristics to drum or this section of separator inlet boiler through pressurization is heated in burning to feedwater after.
The input end of function generator 2 connects the output terminal of a subtracter b, its output terminal connect respectively subtracter a-input end and a subtracter c+input end.The output terminal of subtracter a connects an integrator a, the output terminal connection subtracter b of integrator a+input end.Subtracter c-input end connects the output terminal of a multiplier b, its output terminal connects the input end of an integrator b, the output terminal of integrator b connect subtracter b-input end.This shows that the entry variable of function generator 2 is the deviation of pressure before drum or trap pressure and the machine, this deviation by drum or trap pressure and machine before pressure import subtracter b and calculate, it is output as the corresponding main steam flow of this deviation pressure drop.The function of function generator 2 be simulation from drum or separator outlet to steam turbine this interval pressure-flow characteristic of superheater bringing-up section of boiler the inlet, the flow of main steam the deviometer of pressure is calculated from drum or separator outlet to the superheater bringing-up section of boiler the steam turbine inlet before pressure by drum or separator outlet and the machine, this flow and the deviation that enters the steam flow before boiler-steam dome or the separation vessel calculate the pressure of drum or separator outlet through integrator a.
The input end of function generator 3 connects integrator b output terminal, and its output terminal connects the input end of a multiplier b, the output terminal connection subtracter c of multiplier b-input end.The entry variable of function generator 3 is a pressure before the machine, and it is output as the corresponding down main steam flow of the preceding pressure of this machine.The function of function generator 3 is that the simulation main steam enters the variation characteristic of steam turbine to this section of steam turbine speed control porthole steam turbine acting main steam flow.
The output terminal of function generator 4 connects the input end of multiplier b, and its entry variable is a steam turbine pitch aperture, and it is output as effective steam turbine pitch aperture.The function of function generator 4 is the influences to main steam flow of simulation steam turbine pitch, the main steam flow of the output of its output and function generator 3 after multiplier b product obtains the steam turbine pitch, the output of this main steam flow and function generator 2 calculates deviation through subtracter c, and this deviation input integral device b is calculated pressure before the machine.
About function generator 3, the setting of function generator 4 parameters: at first 3 designs are the x=rated pressure a bit to function generator, the main steam flow during the y=rated load.When unit at fixed pressure operation during the stage, main steam flow when function generator 3 is output as rated load, the ratio of the main steam flow during at this moment according to following main steam flow of different level pressure loads and rated load and the aperture of steam turbine pitch are determined the parameter of function generator 4 each working points.When unit operation during in the sliding pressure section, at this moment the parameter of function generator 4 is determined, it is output as a clear and definite value.When set steady during,, can determine function generator 3 according to pressure before the output of current main steam flow and function generator 4 and the current machine at sliding pressure load.
The input end of function generator 5 connects the output terminal of multiplier b, and its output terminal is contiguous function generator 6 behind an inertial element.The input variable of function generator 5 is the main steam flow behind the steam turbine pitch, and its output is first class pressure behind inertial element.The input variable of function generator 6 is a first class pressure, and its output is unit load behind an inertial element.
The calorific value corrective loop comprises one group of function generator 7~10, and the input end of function generator 7 connects the output terminal of a subtracter d, and its output terminal connects a totalizer g.Subtracter d-input end connects the output terminal of integrator a, it+input end is actual drum or separator outlet pressure.This shows, the deviation that the input variable of function generator 7 calculates through subtracter d for drum or separator outlet pressure in actual drum or separator outlet pressure and the unit model, it is output as the influence of pressure divergence to the boiler fired coal calorific value.
The input end of function generator 8 connects the output terminal of a subtracter e, and its output terminal connects totalizer g.Subtracter e-input end connects the output terminal of integrator b, it+input end is a pressure before the actual machine.This shows that the input variable of function generator 8 is the deviation that pressure calculates through subtracter e before the machine in preceding pressure of actual machine and the unit model, it is output as the influence of pressure divergence to the boiler fired coal calorific value.Function generator 7 and function generator 8 are a function that has little deviation excision.
The input end of function generator 9 connects the output terminal of a subtracter f, and its output terminal connects an integrator c.Subtracter f-input end of input end contiguous function generator 6, it+output terminal is actual first class pressure, the output terminal of integrator c connects the input end of a totalizer h.This shows, the deviation that the input variable of function generator 9 calculates through subtracter f for first class pressure in actual first class pressure and the unit model, its output calculates the basic value of ature of coal calorific value through integrator c.
The input end of function generator 10 connects the output terminal of totalizer g, and its output terminal connects the input end of totalizer h.The output terminal of totalizer h connects the N end of a handoff block, the present calorific value signal of the Y termination of handoff block, and the output terminal of switch connects the input end of multiplier a, and adopts a calorific value to proofread and correct the switching signal of the pulse signal of input as handoff block.The input variable of function generator 10 be before drum or separator outlet pressure and the machine before the drum in pressure and the unit model or separator outlet pressure and the machine deviation of pressure after little deviation excision with, it represents not the matching of energy signal of boiler side steam, this deviation as the part of ature of coal calorific value, improves the dynamic perfromance of value observer after little deviation excision.When does not drop into the calorific value corrective loop in the value observer, the value observer operation independent, the mode switch of carrying out in order to guarantee that boiler can be stable when dropping into, value observer will be followed the tracks of the currency of calorific value, enters the normal counter circuit of calorific value after several seconds.
For the calorific value corrective loop can safety and stability normal operation, when following situation takes place when, excise automatically the calorific value corrective loop: 1, unit load is lower: because it is more single at this moment to enter the coal of boiler, and exist very big non-linear and instability at underload section unit.2, during unit generation fast cutback operating mode: because at this moment the unit operation operating mode is more abominable, operational factor is not within the scope of normal operating condition.When 3, the unit height adds off-the-line: because at this moment owing to there is not high-pressure heater that the water that enters burner hearth is heated, huge variation has taken place in the relation between coal amount and the unit operation parameter that makes, the problem that this operating mode will be studied after being finally makes this device can also can be good at the operational monitoring ature of coal when height adds off-the-line.
Based on the value observer that foregoing is set up, coal-fired value real time monitoring method of the present invention may further comprise the steps:
1) in the DCS control system, searches the actual motion unit under design coal during stable operation, corresponding relation under the different load between each operational factor, operational factor comprise coal amount, steam turbine pitch aperture, unit load, first class pressure, the preceding pressure of machine, drum or separator outlet pressure and main steam flow.
2) by the probability statistics of the operational factor of actual motion unit in the step 1) each parameter in the unit model (mainly being function generator 1~10) is carried out static configuration, make the static output parameter of unit model under each load section can be good at embodying the characteristic of actual motion unit operation parameter.
3) rule of thumb value provides between the inertial time of inertial element in the unit model and the integral time of integrator.
4) parameter of in unit operation unit model being calculated comprises pressure before drum or separator outlet pressure, the machine, first class pressure, unit load, compare analysis with the parameter of actual motion unit: if the final numerical value of each parameter of unit model and the operational factor of actual motion unit are the same, just and the operational factor of actual motion unit the individual mistiming is arranged, then change between the inertial time of corresponding inertial element integral time with integrator; If the operational factor of numerical value that each parameter of unit model is final and actual motion unit is different, then need to revise corresponding function generator, can be good at being complementary up to unit model with the actual motion unit.
5) after unit model can be good at being complementary with the actual motion unit, can open the calorific value calculation module in the value observer, allow the stable operation under different coals of actual motion unit, and the function dead band in the unit model parameter configuration is provided with to eliminate unit parameter self fluctuation and the principle that is changed to that takes place of reflection unit actual energy among a small circle.Calorific value that the inspection value observer calculates and the corresponding situation of the calorific value of actual motion unit coal, the parameter of revising in the calorific value corrective loop makes it to be complementary with actual conditions.
6) as shown in Figure 3, pressure, first class pressure are imported value observer of the present invention before drum that the coal amount signal of in-site measurement and unit is present or separator outlet pressure, the machine, calorific value calculation module in the value observer draws the calorific value corrected parameter after calculating, and the coal amount signal that this calorific value corrected parameter correction is directly measured obtains the coal amount signal of standard.The course of work of the present invention is when the ature of coal variation of actual motion unit, at this moment identical coal amount causes the output parameter of actual motion unit can be lower than the parameter under the identical mark coal, at this moment the present invention can reduce the calorific value signal of ature of coal, make the standard coal equivalent amount of converting out reduce through the calorific value signal, this makes that the output meeting of unit model is the same with the actual parameter of actual motion unit, and calorific value has at this moment also characterized the present calorific value situation of actual motion unit.It is same when the ature of coal of actual motion unit improves, at this moment identical coal amount causes the output parameter of actual motion unit can be than the parameter height under the identical mark coal, at this moment the present invention can increase the calorific value signal of ature of coal, make the standard coal equivalent amount of converting out increase through the calorific value signal, this makes that the output meeting of unit model is the same with the actual parameter of actual motion unit, and calorific value has at this moment also characterized the present calorific value situation of actual motion unit.
As shown in Figure 4, be when adopting the present invention to use the coal pulverizer start and stop of the better coal of calorific value in certain power plant, the changing trend diagram in the calorific value corrected signal 15 hours.This figure shows when using the coal pulverizer start and stop of the better coal of calorific value, cause the total calorific value that enters boiler fuel that variation has taken place, calorific value corrected signal of the present invention is also along with variation has taken place in the start and stop of the coal pulverizer that has used coal, and the startup along with mill becomes 1.007 again after 0.972 when mill becomes when stopping from 1.019.According to this curve as can be seen, the calorific value signal that the present invention calculated, real-time reflection enter the variation that the calorific value of boiler fuel takes place.
Although disclose preferred embodiment of the present invention and accompanying drawing for the purpose of illustration, its purpose is to help to understand content of the present invention and implement according to this, but person skilled in the art, without departing from the spirit and scope of the invention and the appended claims, can do various replacements, variation and retouching.Therefore, the present invention should not be limited to most preferred embodiment and the disclosed content of accompanying drawing, and protection scope of the present invention is as the criterion with the scope that appending claims was defined.