CN103759769A - Soft measurement method and device for reheat steam flow of coal-fired power plant - Google Patents

Abstract

The invention discloses a soft measurement method and device for reheat steam flow of a coal-fired power plant. Work condition parameters are detected in real time, the sum of first-grade steam extraction flow D1 and second-grade steam extraction flow D2 is calculated, the accurate value Drj (t) of the reheat steam flow is calculated by utilizing the sum of the first-grade steam extraction flow D1 and the second-grade steam extraction flow D2, an existing heat balance formula is simplified, and then the high-accuracy soft measurement result of the reheat steam flow is obtained. Meanwhile, the dynamic value Drf (t) of the reheat steam flow is determined by utilizing grade front parameters, and information fusion is carried out on the accurate value Drj (t) and the dynamic value Drf (t) of the reheat steam flow to obtain the final soft measurement value Dr (t) of the reheat steam flow. In the information fusion process, errors generated when Drf (t) calculates the stable work conditions are restrained through a filter function, therefore, the soft measurement value Dr (t) of the reheat steam flow has the accuracy of the accurate value Drj (t) of the reheat steam flow and the dynamic characteristics of the dynamic value Drf (t) of the reheat steam flow, and the accuracy of boiler calculation indexes can be improved.

Description

Coal fired power plant reheated steam flow soft measurement method and apparatus

Technical field

The present invention relates to field of measuring technique, particularly a kind of coal fired power plant reheated steam flow soft measurement method and apparatus.

Background technology

Reheated steam flow is usually used in calculating the important indicator of some supervision boiler steam turbine states, as boiler exhaust gas oxygen level and steam turbine heat consumption rate, is important station boiler parameter.Reheated steam flow does not conventionally have measuring point in actual station boiler monitoring system, and the data of reheated steam flow at present used are all by indirect calculation gained.Present Thermal Power factory generally bears load peak regulation task, and the significantly variation of boiler load causes the significantly variation of reheated steam flow, and this proposes higher requirement to accuracy and real-time of improving computing method.Therefore improve accuracy and the real-time of reheated steam method of calculating flux, the accuracy that is conducive to improve boiler calculation index, plays an important role to the effect that improves energy saving optimizing.

Below the measuring method of existing station boiler reheated steam flow is introduced.

1) determine Y-factor method Y

Regard the ratio of reheated steam flow and main steam flow as definite value,

D _r=kD _s （1）

In formula, D _r, D _sbe respectively reheated steam flow and main steam flow, unit is t/h.K is definite value, generally between 0.82～0.92.

2) adopt intermediate pressure cylinder inlet steam pressure and temp computing method

The theoretical foundation of this method is Fu Liugeer formula:

$\frac{D_1}{D_0}=\frac{P_1}{P_0}\sqrt{\frac{T_0}{T_1}}---\left(2\right)$

Wherein, D is intermediate pressure cylinder entrance reheated steam flow, and unit is t/h, and T is intermediate pressure cylinder inlet steam temperature, and unit is K, and P is intermediate pressure cylinder inlet steam pressure, and unit is Mpa.Wherein, subscript 0 represents ratings, and 1 represents actual value.

3) differential pressure method

Intermediate pressure cylinder entrance reheated steam flow can be determined by following formula:

$D_r=D_s-\underset{i}{\mathrm{\Σ}}{D}_i-D_l+D_j---\left(3\right)$

Wherein, D _sfor main steam flow, D _lfor regulating porthole door bar and shaft gland steam leakage, D _jfor hot desuperheat spray flow again, unit is t/h, D _ifor again heat before extraction flows at different levels.For the unit that there is no main steam flow measuring point, main steam flow D _scan be taken as feedwater flow and overheated spray desuperheating flow sum.For regulating porthole door bar and shaft-packing leakage amount D _lcalculating because the data that needs gather are more, calculate loaded down with trivial detailsly, its proportion compared with the amount of drawing gas before heat is again less in addition, so can think D _lvariation less on the calculating impact of reheated steam flow, can rule of thumb be taken as definite value.Hot desuperheat spray flow D again _jthere is on-the-spot measuring point.Extraction flow D at different levels before heat again _ican be provided by following momentum equation:

$p_i-p_{\mathrm{si}}=T_T\frac{D_i^2}{{\mathrm{\ρ}}_i}---\left(4\right)$

Wherein, D _i, p _i, ρ _ibe i level extraction flow, pressure and density, corresponding unit is respectively t/h, Mpa and kg/m ³, p _sibe the saturation pressure of i level high-pressure heater, unit is Mpa, R _tfor the total drag coefficients of extraction line and reverse checkvalve.

Conventionally, in formula (3), i is 2.Therefore formula (3) can be expressed as

D _rj(t)=D _s-(D ₁+D ₂)-D _l+D _j （5）

4) heat balance method of

Here, intermediate pressure cylinder entrance reheated steam flow still can be determined by formula (5).Wherein extraction flow D at different levels before the heat again in formula (5) ₁and D ₂calculating can be obtained by thermally equilibrated mode, when stable state, flows into the energy of well heater and flows out the energy of well heater and equate, thermal balance equation is exactly the equation listed according to the relation of this energy equilibrium.If measuring point is enough, by thermal balance equation, can obtain extraction flow accurately.For the genset that has two-stage high-pressure heater before heat again, for a high-pressure heater, can obtain

D _fwH _f2+D ₁H _c1-D ₁H _s1=D _fwH _f1 （6）

For No. two high-pressure heaters, can obtain

D _fwH _f3+D ₂H _c2-(D ₂+D ₁)H _s2+D ₁H _s1=D _fwH _f2 （7）

Wherein, D _fwfor feedwater flow, unit is t/h; D ₁and D ₂be respectively first order extraction flow and second level extraction flow, unit is t/h; H _f1, H _f2, H _f3be respectively No. one, No. two and No. three high-pressure heater outlet Enthalpy of Feed Water, unit is kJ/kg; H _c1, H _c2be respectively the firsts and seconds enthalpy that draws gas, unit is kJ/kg; H _s1, H _s2be respectively No. one and No. two hydrophobic enthalpies of high-pressure heater, unit is kJ/kg.

By above-mentioned two formulas, can be obtained:

$D_1+D_2=D_{\mathrm{fw}}\frac{H_{c2}(H_{f1}-H_{f2})-H_{s1}(H_{f1}-H_{f3})+H_{c1}(H_{f2}-H_{f3})}{(H_{c1}-H_{s1})(H_{c2}-H_{s2})}---\left(8\right)$

Wherein, definition q ₁=H _c1-H _s1for the one-level thermal discharge that draws gas, q ₂=H _c2-H _s2for the secondary thermal discharge that draws gas, h ₁=H _f1-H _f2be a high pressure water feeder feedwater caloric receptivity, h ₂=H _f2-H _f3be No. two high pressure water feeder feedwater caloric receptivities, h ₃=H _f1-H _f3it is the summation of No. one, No. two high pressure water feeder feedwater caloric receptivities.Have:

$D_1+D_2=D_{\mathrm{fw}}\frac{H_{c2}{h}_1-H_{s1}{h}_3+H_{c1}{h}_2}{q_1{q}_2}---\left(9\right)$

Although existing measuring method can obtain the value of reheated steam flow, but in actual motion, reheated steam flow changes at any time, result or deviation that existing measuring method obtains are larger, or be difficult to on-line implement, cannot there is real-time simultaneously and guarantee degree of accuracy.The defect that above-mentioned several method exists is as follows:

1) determine the shortcoming of Y-factor method Y.Genset is in actual motion, and due to the impact of factors, load fluctuation is frequent, and the change of the method for operation, operational factor in addition makes the reheated steam flow calculating can not reflect real reheated steam flow.

2) shortcoming of employing intermediate pressure cylinder inlet steam pressure and temp computing method.Fu Liugeer formula is not an accurate computing formula, because its derivation comprises hypothesis.Accuracy is poor, but can substantially meet service requirement.

3) shortcoming of differential pressure method.Due to actual set, in when operation, can not to survey factor very many, and the amount of the drawing gas mistake extent that this method obtains is inestimable.

4) shortcoming of heat balance method of.Heat balance method of result of calculation is accurate, but its required measuring point is more, calculation of complex, and due to the existence of middle volume link, this formula is only applicable to steady state condition.

Summary of the invention

The embodiment of the present invention provides a kind of coal fired power plant reheated steam flow soft measurement method and apparatus.By existing heat balance equation is simplified, obtain reheated steam flow exact value, before also utilizing level, parameter is determined reheated steam flow dynamics value simultaneously, reheated steam flow exact value and reheated steam flow dynamics value are carried out to information fusion, to obtain final reheated steam flow soft measurement value, thereby make reheated steam flow soft measurement value there is the precision of reheated steam flow exact value and the dynamic perfromance of reheated steam flow dynamics value, the accuracy that is conducive to improve boiler calculation index simultaneously.

According to an aspect of the present invention, provide a kind of coal fired power plant reheated steam flow soft measurement method, comprising:

Detect in real time duty parameter, wherein duty parameter comprises feedwater flow D _fw, the pressure and temperature of a high-pressure heater outlet feedwater, pressure and temperature, one-level extraction pressure and temperature, secondary extraction pressure and the temperature of No. three high-pressure heaters outlet feedwater;

Utilize the pressure and temperature of a high-pressure heater outlet feedwater to calculate high-pressure heater outlet Enthalpy of Feed Water H No. one _f1, utilize the pressure and temperature of No. three high-pressure heater outlet feedwater to calculate high-pressure heater outlet Enthalpy of Feed Water H No. three _f3, utilize one-level extraction pressure and the temperature computation one-level enthalpy H that draws gas _c1, utilize secondary extraction pressure and the temperature computation secondary enthalpy H that draws gas _c2, utilize H _f1and H _f3calculate a high-pressure heater and No. two high-pressure heater feedwater caloric receptivity summation h ₃, utilize H _c1and H _c2calculate the secondary thermal discharge q that draws gas ₂;

Utilize feedwater flow D _fw, a high-pressure heater and No. two high-pressure heaters feedwater caloric receptivity summation h ₃with the secondary thermal discharge q that draws gas ₂, calculate first order extraction flow D ₁with second level extraction flow D ₂sum;

Utilize first order extraction flow D ₁with second level extraction flow D ₂sum is calculated reheated steam flow exact value D _rj(t).

In one embodiment, duty parameter also comprises main steam flow D _s, regulate porthole door bar and shaft gland steam leakage D _l, hotter desuperheat spray flow D _j;

Reheated steam flow exact value D _rj(t) be

D _rj(t)=D _s-(D ₁+D ₂)-D _l+D _j。

In one embodiment, utilize formula

$D_1+D_2=f\left(D_{\mathrm{fw}}\frac{h_3}{q_2}\right)$

Calculate first order extraction flow D ₁with second level extraction flow D ₂sum.

In one embodiment, duty parameter also comprises intermediate pressure cylinder inlet steam pressure P, intermediate pressure cylinder inlet steam temperature T;

Utilize first order extraction flow D ₁with second level extraction flow D ₂sum is calculated reheated steam flow exact value D _rj(t), after step, also comprise:

Utilize the front parameter of level determine reheated steam flow dynamics value D _rf(t);

By reheated steam flow exact value D _rjand reheated steam flow dynamics value D (t) _rf(t) carry out information fusion, to obtain final reheated steam flow soft measurement value D _r(t).

Preferably, reheated steam flow soft measurement value D _r(t) be:

D _r(t)=D _rj(t)+F[D _rf(t)-D _rj(t)]

Wherein F is filter function, for suppressing D _rf(t) error producing when calculating steady state condition, so that reheated steam flow soft measurement value D _r(t) there is reheated steam flow exact value D simultaneously _rj(t) precision and reheated steam flow dynamics value D _rf(t) dynamic perfromance.

According to a further aspect in the invention, provide a kind of coal fired power plant reheated steam flow soft measurement device, comprise detecting unit, parameter calculation unit, extraction flow computing unit and flow exact value computing unit, wherein:

Detecting unit, for detecting in real time duty parameter, wherein duty parameter comprises feedwater flow D _fw, the pressure and temperature of a high-pressure heater outlet feedwater, pressure and temperature, one-level extraction pressure and temperature, secondary extraction pressure and the temperature of No. three high-pressure heaters outlet feedwater;

Parameter calculation unit, for utilizing the pressure and temperature of a high-pressure heater outlet feedwater to calculate high-pressure heater outlet Enthalpy of Feed Water H No. one _f1, utilize the pressure and temperature of No. three high-pressure heater outlet feedwater to calculate high-pressure heater outlet Enthalpy of Feed Water H No. three _f3, utilize one-level extraction pressure and the temperature computation one-level enthalpy H that draws gas _c1, utilize secondary extraction pressure and the temperature computation secondary enthalpy H that draws gas _c2; Utilize H _f1and H _f3calculate a high-pressure heater and No. two high-pressure heater feedwater caloric receptivity summation h ₃, utilize H _c1and H _c2calculate the secondary thermal discharge q that draws gas ₂;

Extraction flow computing unit, for utilizing feedwater flow D _fw, a high-pressure heater and No. two high-pressure heaters feedwater caloric receptivity summation h ₃with the secondary thermal discharge q that draws gas ₂, calculate first order extraction flow D ₁with second level extraction flow D ₂sum;

Flow exact value computing unit, for utilizing first order extraction flow D ₁with second level extraction flow D ₂sum is calculated reheated steam flow exact value D _rj(t).

In one embodiment, duty parameter also comprises main steam flow D _s, regulate porthole door bar and shaft gland steam leakage D _l, hotter desuperheat spray flow D _j;

Flow exact value computing unit specifically utilizes formula

D _rj(t)=D _s-(D ₁+D ₂)-D _l+D _j。

Calculate reheated steam flow exact value D _rj(t).

In one embodiment, extraction flow computing unit specifically utilizes formula

$D_1+D_2=f\left(D_{\mathrm{fw}}\frac{h_3}{q_2}\right)$

Calculate first order extraction flow D ₁with second level extraction flow D ₂sum.

In one embodiment, said apparatus also comprises flow dynamics value computing unit and information fusion unit, wherein:

Duty parameter also comprises intermediate pressure cylinder inlet steam pressure P, intermediate pressure cylinder inlet steam temperature T;

Flow dynamics value computing unit, for utilizing a grade front parameter

determine reheated steam flow dynamics value D _rf(t);

Information fusion unit, for by reheated steam flow exact value D _rjand reheated steam flow dynamics value D (t) _rf(t) carry out information fusion, to obtain final reheated steam flow soft measurement value D _r(t).

In one embodiment, information fusion unit specifically utilizes formula:

D _r(t)=D _rj(t)+F[D _rf(t)-D _rj(t)]

Calculate reheated steam flow soft measurement value D _r(t), wherein F is filter function, for suppressing D _rf(t) error producing when calculating steady state condition, so that reheated steam flow soft measurement value D _r(t) there is reheated steam flow exact value D simultaneously _rj(t) precision and reheated steam flow dynamics value D _rf(t) dynamic perfromance.

By the detailed description to exemplary embodiment of the present with reference to the following drawings, further feature of the present invention and advantage thereof will become apparent.

Accompanying drawing explanation

In order to be illustrated more clearly in the embodiment of the present invention or technical scheme of the prior art, to the accompanying drawing of required use in embodiment or description of the Prior Art be briefly described below, apparently, accompanying drawing in the following describes is only some embodiments of the present invention, for those of ordinary skills, do not paying under the prerequisite of creative work, can also obtain according to these accompanying drawings other accompanying drawing.

Fig. 1 is the schematic diagram of an embodiment of coal fired power plant reheated steam flow soft measurement method of the present invention.

Fig. 2 is the schematic diagram of another embodiment of coal fired power plant reheated steam flow soft measurement method of the present invention.

Fig. 3 is the schematic diagram of an embodiment of coal fired power plant reheated steam flow soft measurement device of the present invention.

Fig. 4 is the schematic diagram of another embodiment of coal fired power plant reheated steam flow soft measurement device of the present invention.

Embodiment

Below in conjunction with the accompanying drawing in the embodiment of the present invention, the technical scheme in the embodiment of the present invention is clearly and completely described, obviously, described embodiment is only the present invention's part embodiment, rather than whole embodiment.To the description only actually of at least one exemplary embodiment, be illustrative below, never as any restriction to the present invention and application or use.Based on the embodiment in the present invention, those of ordinary skills, not making the every other embodiment obtaining under creative work prerequisite, belong to the scope of protection of the invention.

Unless illustrate in addition, otherwise the parts of setting forth in these embodiments and positioned opposite, numeral expression formula and the numerical value of step not limited the scope of the invention.

, it should be understood that for convenience of description, the size of the various piece shown in accompanying drawing is not to draw according to actual proportionate relationship meanwhile.

For the known technology of person of ordinary skill in the relevant, method and apparatus, may not discuss in detail, but in suitable situation, described technology, method and apparatus should be regarded as authorizing a part for instructions.

In all examples with discussing shown here, it is exemplary that any occurrence should be construed as merely, rather than as restriction.Therefore, other example of exemplary embodiment can have different values.

It should be noted that: in similar label and letter accompanying drawing below, represent similar terms, therefore, once be defined in an a certain Xiang Yi accompanying drawing, in accompanying drawing subsequently, do not need it to be further discussed.

Fig. 1 is the schematic diagram of an embodiment of coal fired power plant reheated steam flow soft measurement method of the present invention.As shown in Figure 1, the method step of the present embodiment is as follows:

Step 101, detects duty parameter in real time, and wherein duty parameter comprises feedwater flow D _fw, the pressure and temperature of a high-pressure heater outlet feedwater, pressure and temperature, one-level extraction pressure and temperature, secondary extraction pressure and the temperature of No. three high-pressure heaters outlet feedwater.

Step 102, utilizes the pressure and temperature of a high-pressure heater outlet feedwater to calculate high-pressure heater outlet Enthalpy of Feed Water H No. one _f1, utilize the pressure and temperature of No. three high-pressure heater outlet feedwater to calculate high-pressure heater outlet Enthalpy of Feed Water H No. three _f3, utilize one-level extraction pressure and the temperature computation one-level enthalpy H that draws gas _c1, utilize secondary extraction pressure and the temperature computation secondary enthalpy H that draws gas _c2, utilize H _f1and H _f3calculate a high-pressure heater and No. two high-pressure heater feedwater caloric receptivity summation h ₃, utilize H _c1and H _c2calculate the secondary thermal discharge q that draws gas ₂.

Step 103, utilizes feedwater flow D _fw, a high-pressure heater and No. two high-pressure heaters feedwater caloric receptivity summation h ₃with the secondary thermal discharge q that draws gas ₂, calculate first order extraction flow D ₁with second level extraction flow D ₂sum.

Preferably, utilize formula

$D_1+D_2=f\left(D_{\mathrm{fw}}\frac{h_3}{q_2}\right)$

Calculate first order extraction flow D ₁with second level extraction flow D ₂sum.

Step 104, utilizes first order extraction flow D ₁with second level extraction flow D ₂sum is calculated reheated steam flow exact value D _rj(t).

The coal fired power plant reheated steam flow soft measurement method providing based on the above embodiment of the present invention, by existing heat balance equation is simplified, thereby obtains high-precision reheated steam flow soft measurement result.

Below the simplification of heat balance method of is elaborated.

In heat balance method of, intermediate pressure cylinder entrance reheated steam hot junction flow can by formula (5) determine, wherein again heat before extraction flow D at different levels ₁and D ₂computing method be formula (9).

Because of H _c1≈ H _c2, formula (9) can be write as:

$D_1+D_2\≈D_{\mathrm{fw}}\frac{H_{c1}{h}_3-H_{s1}{h}_3}{q_1{q}_2}=D_{\mathrm{fw}}\frac{q_1{h}_3}{q_1{q}_2}=D_{\mathrm{fw}}\frac{h_3}{q_2}---\left(10\right)$

So the data measuring point of institute's palpus has reduced nearly half.But computational accuracy decreases, error, in 2.45% to 2.85% scope, can consider that power plant's actual operating data revises, to improve computational accuracy.

In order to improve the computational accuracy of simplifying heat balance method of, the service data of optional power taking factory's period, is used heat balance method of to calculate the front extraction flow D at different levels of heat again ₁and D ₂, use the heat balance method of of simplifying to calculate

by both data fittings.

Obtaining D ₁and D ₂after, just can utilize the correlation formula of heat balance method of to calculate the exact value D of reheated steam flow _rj(t), be specially

D _rj(t)=D _s-(D ₁+D ₂)-D _l+D _j

Wherein D _sfor main steam flow, D _lfor regulating porthole door bar and shaft gland steam leakage, D _jfor hot desuperheat spray flow again.

Here it should be noted that, due to the existence of middle volume link, reheated steam flow all has inertia to delay to the response of each factors vary, so high-precision computing formula is only applicable to the calculating of reheated steam flow under steady state condition.When unit is when dynamic, utilize this formula to calculate and obviously can produce larger error.Consider that Fu Liugeer formula is applicable to dynamic operation condition, make improvements, to improve the computational accuracy of this formula.

Fig. 2 is the schematic diagram of another embodiment of coal fired power plant reheated steam flow soft measurement method of the present invention.Wherein step 201-204 is identical with the step 101-104 in embodiment illustrated in fig. 1.

Step 201, detects duty parameter in real time, and wherein duty parameter comprises feedwater flow D _fw, the pressure and temperature of a high-pressure heater outlet feedwater, pressure and temperature, one-level extraction pressure and temperature, secondary extraction pressure and the temperature of No. three high-pressure heaters outlet feedwater.

Step 202, utilizes the pressure and temperature of a high-pressure heater outlet feedwater to calculate high-pressure heater outlet Enthalpy of Feed Water H No. one _f1, utilize the pressure and temperature of No. three high-pressure heater outlet feedwater to calculate high-pressure heater outlet Enthalpy of Feed Water H No. three _f3, utilize one-level extraction pressure and the temperature computation one-level enthalpy H that draws gas _c1, utilize secondary extraction pressure and the temperature computation secondary enthalpy H that draws gas _c2, utilize H _f1and H _f3calculate a high-pressure heater and No. two high-pressure heater feedwater caloric receptivity summation h ₃, utilize H _c1and H _c2calculate the secondary thermal discharge q that draws gas ₂.

Step 203, utilizes feedwater flow D _fw, a high-pressure heater and No. two high-pressure heaters feedwater caloric receptivity summation h ₃with the secondary thermal discharge q that draws gas ₂, calculate first order extraction flow D ₁with second level extraction flow D ₂sum.

Step 204, utilizes first order extraction flow D ₁with second level extraction flow D ₂sum is calculated reheated steam flow exact value D _rj(t).

Step 205, utilizes the front parameter of level

determine reheated steam flow dynamics value D _rf(t).

That is, $D_{\mathrm{rf}}\left(t\right)=f\left(\frac{P}{\sqrt{T}}\right).$

Wherein, P is intermediate pressure cylinder inlet steam pressure, and T is intermediate pressure cylinder inlet steam temperature.

Step 206, by reheated steam flow exact value D _rjand reheated steam flow dynamics value D (t) _rf(t) carry out information fusion, to obtain final reheated steam flow soft measurement value D _r(t).

Here it should be noted that, Fu Liugeer formula thinks that the steam flow of stage group is proportional to a grade front parameter

but when variable working condition on a large scale, the error of calculation that this relation is brought can along with the actual condition of unit depart from benchmark operating mode degree increase and increase.In order to eliminate this error, reheated steam flow and the front parameter of level when matching actual set is moved under different working conditions

funtcional relationship.

Improved Fu Liugeer formula is applicable to dynamic calculation, but accuracy in computation is poor, can consider the heat balance method of of simplification and improved Fu Liugeer formula to carry out information fusion, to realize mutual supplement with each other's advantages.

Information fusion is the emerging technology growing up in recent years, it makes full use of multiple sensor resources, by reasonable domination and use to these sensors and observation information thereof, multiple sensors in space or temporal redundancy or complementary information according to certain criterion, combine, the more superior performance of system that this sensing system is obtained thus form than the subset of its each ingredient.The stable state accuracy of simplifying heat balance method of is high, and the stable state accuracy of improved Fu Liugeer formula is not as heat balance equation, but its dynamic accuracy is high, and the flow value of the reheated steam that these two kinds of methods are calculated is regarded an information fusion pair as, wishes

Wherein, D _rj(t) for simplifying the reheated steam flow rate calculation value of heat balance equation, D _rf(t) be the reheated steam flow rate calculation value of improved Fu Liugeer formula, p _tfor the main steam pressure of steam turbine, unit is Mpa, and t is the time, and unit is s.

Error when improved Fu Liugeer formula is calculated to steady state condition is regarded a kind of low-frequency disturbance as, has

D _rf(t)=D _rj(t)+N(t) （12）

In formula, N (t)=D _rf(t)-D _rj(t).If want, suppress the impact of this interference on low-frequency range, should before interference, add Hi-pass filter.The filter construction form of selecting to be simply easy to Project Realization, has

$G\left(s\right)=\frac{\mathrm{Ts}}{\mathrm{Ts}+1}---\left(13\right)$

G in formula (s) is the transport function of wave filter; S is the complex variable of pull-type conversion; T is inertia time (s).

The reheated steam flow soft measurement value D finally obtaining _r(t) be:

D _r(t)=D _rj(t)+F[D _rf(t)-D _rj(t)] （14）

Wherein F is filter function, for suppressing D _rf(t) error producing when calculating steady state condition, so that reheated steam flow soft measurement value D _r(t) there is reheated steam flow exact value D simultaneously _rj(t) precision and reheated steam flow dynamics value D _rf(t) dynamic perfromance.

Preferably, F can be the filter construction shown in formula (13).Can find out, select suitable T value, when set state is stablized, what this formula was extracted is to simplify the reheated steam flow information that heat balance equation calculates; When unit is when dynamic, the information of improved Fu Liugeer formula calculated value has been occupied again advantage, has realized the information fusion of these two kinds of methods on time domain and frequency domain.

Fig. 3 is the schematic diagram of an embodiment of coal fired power plant reheated steam flow soft measurement device of the present invention.As shown in Figure 3, this device comprises detecting unit 301, parameter calculation unit 302, extraction flow computing unit 303 and flow exact value computing unit 304.Wherein:

Detecting unit 301, for detecting in real time duty parameter, wherein duty parameter comprises feedwater flow D _fw, the pressure and temperature of a high-pressure heater outlet feedwater, pressure and temperature, one-level extraction pressure and temperature, secondary extraction pressure and the temperature of No. three high-pressure heaters outlet feedwater.

Parameter calculation unit 302, for utilizing the pressure and temperature of a high-pressure heater outlet feedwater to calculate high-pressure heater outlet Enthalpy of Feed Water H No. one _f1, utilize the pressure and temperature of No. three high-pressure heater outlet feedwater to calculate high-pressure heater outlet Enthalpy of Feed Water H No. three _f3, utilize one-level extraction pressure and the temperature computation one-level enthalpy H that draws gas _c1, utilize secondary extraction pressure and the temperature computation secondary enthalpy H that draws gas _c2; Utilize H _f1and H _f3calculate a high-pressure heater and No. two high-pressure heater feedwater caloric receptivity summation h ₃, utilize H _c1and H _c2calculate the secondary thermal discharge q2 that draws gas.

Extraction flow computing unit 303, for utilizing feedwater flow D _fw, a high-pressure heater and No. two high-pressure heaters feedwater caloric receptivity summation h ₃with the secondary thermal discharge q that draws gas ₂, calculate first order extraction flow D ₁with second level extraction flow D ₂sum.

Preferably, extraction flow computing unit specifically utilizes formula

$D_1+D_2=f\left(D_{\mathrm{fw}}\frac{h_3}{q_2}\right)$

Calculate first order extraction flow D ₁with second level extraction flow D ₂sum.

Flow exact value computing unit 304, for utilizing first order extraction flow D ₁with second level extraction flow D ₂sum is calculated reheated steam flow exact value D _rj(t).

The coal fired power plant reheated steam flow soft measurement device providing based on the above embodiment of the present invention, by existing heat balance equation is simplified, thereby obtains high-precision reheated steam flow soft measurement result.

In one embodiment, duty parameter also comprises main steam flow D _s, regulate porthole door bar and shaft gland steam leakage D _l, hotter desuperheat spray flow D _j.

Flow exact value computing unit 304 specifically utilizes formula

D _rj(t)=D _s-(D ₁+D ₂)-D _l+D _j。

Calculate reheated steam flow exact value D _rj(t).

Fig. 4 is the schematic diagram of another embodiment of coal fired power plant reheated steam flow soft measurement device of the present invention.Compared with embodiment illustrated in fig. 3, in the embodiment shown in fig. 4, said apparatus also comprises flow dynamics value computing unit 401 and information fusion unit 402.Wherein:

Duty parameter also comprises intermediate pressure cylinder inlet steam pressure P, intermediate pressure cylinder inlet steam temperature T;

Flow dynamics value computing unit 401, for utilizing a grade front parameter

determine reheated steam flow dynamics value D _rf(t).That is,

Information fusion unit 402, for by reheated steam flow exact value D _rjand reheated steam flow dynamics value D (t) _rf(t) carry out information fusion, to obtain final reheated steam flow soft measurement value D _r(t).

Preferably, information fusion unit 402 specifically utilizes formula:

D _r(t)=D _rj(t)+F[D _rf(t)-D _rj(t)]

Calculate reheated steam flow soft measurement value D _r(t), wherein F is filter function, for suppressing D _rf(t) error producing when calculating steady state condition, so that reheated steam flow soft measurement value D _r(t) there is reheated steam flow exact value D simultaneously _rj(t) precision and reheated steam flow dynamics value D _rf(t) dynamic perfromance.

Below by a concrete field conduct scheme, the present invention will be described.

1) original signal collection

Need to gather vapor pressure p and temperature signal T, the feedwater flow signal D of the outlet of boiler side reheated steam _fw, reheater desuperheating water flow signal D _j, steamer pusher side high-pressure heaters at different levels are bled and the temperature, pressure value of hydrophobic temperature, pressure value, high-pressure heater outlet feedwater.

For the unit that has main steam flow measuring point, gather main steam flow D _s; For the unit that there is no main steam flow measuring point, gather overheated spray desuperheating flow.

2) configuration of algorithm in computing platform

Extract the actual operating data that high-pressure heater is bled, hydrophobic and outlet is fed water, determine the fitting constant of the amount of drawing gas, extract actual operating data or the reliable design experiment data of reheated steam top hole pressure temperature, determine the fitting constant of reheated steam flow dynamics value.According to the industrial water and steam thermodynamic properties of IAPWS-IF95(computing formula), by the high-pressure heater hydrophobic and outlet feed temperature force value of bleeding, calculate the enthalpy hydrophobic and outlet feedwater of bleeding, and then obtain the secondary thermal discharge q that draws gas ₂add with high the summation h that feedwater recepts the caloric ₃.According to feedwater flow measuring point, can calculate again the front extraction flows at different levels of heat.

By main steam flow D _s, regulate porthole door bar and shaft gland steam leakage D _lwith reheater desuperheating water flow signal D _j, according to formula (5), calculate reheated steam flow D _rj.The vapor pressure p being exported by reheated steam and temperature signal T, can obtain reheated steam flow D _rf.

By the mode of information fusion, the reheated steam flow D after being merged _r, filter construction form as shown in Equation (13).

By implementing the present invention, can obtain following beneficial effect:

1) rapid dynamic response speed, static accuracy is high.The heat balance method of of simplifying in the present invention and improved Fu Liugeer formula have been considered the practical operation situation of Power Plant, and while being applied in corresponding boiler unit, accuracy in computation is high.The reheated steam flow that application message integration technology obtains, has the high and high feature of improved Fu Liugeer formula dynamic accuracy of the heat balance method of stable state accuracy of simplification, has rapid dynamic response speed, the advantage that static accuracy is high.

2) reliability is high.The signals such as feedwater flow of the present invention, intermediate pressure cylinder reheated steam inlet pressure, temperature are the most important Monitoring and Controlling signal of power plant units, have the highest reliability step, and the reheated steam flow therefore obtaining has same reliability.

3) computation process is simple, and it is convenient to implement.Original heat balance method of is simplified and fitting formula after, required data measuring point reduces a lot, it is convenient to implement.

One of ordinary skill in the art will appreciate that all or part of step that realizes above-described embodiment can complete by hardware, also can carry out the hardware that instruction is relevant by program completes, described program can be stored in a kind of computer-readable recording medium, the above-mentioned storage medium of mentioning can be ROM (read-only memory), disk or CD etc.

Description of the invention provides for example with for the purpose of describing, and is not exhaustively or limit the invention to disclosed form.Many modifications and variations are obvious for the ordinary skill in the art.Selecting and describing embodiment is for better explanation principle of the present invention and practical application, thereby and makes those of ordinary skill in the art can understand the present invention's design to be suitable for the various embodiment with various modifications of special-purpose.

Claims (10)

1. a coal fired power plant reheated steam flow soft measurement method, is characterized in that, comprising:

Detect in real time duty parameter, wherein duty parameter comprises feedwater flow D _fw, the pressure and temperature of a high-pressure heater outlet feedwater, pressure and temperature, one-level extraction pressure and temperature, secondary extraction pressure and the temperature of No. three high-pressure heaters outlet feedwater;

Utilize the pressure and temperature of a high-pressure heater outlet feedwater to calculate high-pressure heater outlet Enthalpy of Feed Water H No. one _f1, utilize the pressure and temperature of No. three high-pressure heater outlet feedwater to calculate high-pressure heater outlet Enthalpy of Feed Water H No. three _f3, utilize one-level extraction pressure and the temperature computation one-level enthalpy H that draws gas _c1, utilize secondary extraction pressure and the temperature computation secondary enthalpy H that draws gas _c2, utilize H _f1and H _f3calculate a high-pressure heater and No. two high-pressure heater feedwater caloric receptivity summation h ₃, utilize H _c1and H _c2calculate the secondary thermal discharge q that draws gas ₂;

Utilize feedwater flow D _fw, a high-pressure heater and No. two high-pressure heaters feedwater caloric receptivity summation h ₃with the secondary thermal discharge q that draws gas ₂, calculate first order extraction flow D ₁with second level extraction flow D ₂sum;

Utilize first order extraction flow D ₁with second level extraction flow D ₂sum is calculated reheated steam flow exact value D _rj(t).

2. method according to claim 1, is characterized in that,

Duty parameter also comprises main steam flow D _s, regulate porthole door bar and shaft gland steam leakage D _l, hotter desuperheat spray flow D _j;

Reheated steam flow exact value D _rj(t) be

D _rj(t)=D _s-(D ₁+D ₂)-D _l+D _j。

3. method according to claim 1 and 2, is characterized in that,

Utilize formula

$D_1+D_2=f\left(D_{\mathrm{fw}}\frac{h_3}{q_2}\right)$

Calculate first order extraction flow D ₁with second level extraction flow D ₂sum.

4. method according to claim 1 and 2, is characterized in that,

Duty parameter also comprises intermediate pressure cylinder inlet steam pressure P, intermediate pressure cylinder inlet steam temperature T;

Utilize first order extraction flow D ₁with second level extraction flow D ₂sum is calculated reheated steam flow exact value D _rj(t), after step, also comprise:

Utilize the front parameter of level

determine reheated steam flow dynamics value D _rf(t);

By reheated steam flow exact value D _rjand reheated steam flow dynamics value D (t) _rf(t) carry out information fusion, to obtain final reheated steam flow soft measurement value D _r(t).

5. method according to claim 4, is characterized in that,

Reheated steam flow soft measurement value D _r(t) be:

D _r(t)=D _rj(t)+F[D _rf(t)-D _rj(t)]

Wherein F is filter function, for suppressing D _rf(t) error producing when calculating steady state condition, so that reheated steam flow soft measurement value D _r(t) there is reheated steam flow exact value D simultaneously _rj(t) precision and reheated steam flow dynamics value D _rf(t) dynamic perfromance.

6. a coal fired power plant reheated steam flow soft measurement device, is characterized in that, comprises detecting unit, parameter calculation unit, extraction flow computing unit and flow exact value computing unit, wherein:

Detecting unit, for detecting in real time duty parameter, wherein duty parameter comprises feedwater flow D _fw, the pressure and temperature of a high-pressure heater outlet feedwater, pressure and temperature, one-level extraction pressure and temperature, secondary extraction pressure and the temperature of No. three high-pressure heaters outlet feedwater;

Parameter calculation unit, for utilizing the pressure and temperature of a high-pressure heater outlet feedwater to calculate high-pressure heater outlet Enthalpy of Feed Water H No. one _f1, utilize the pressure and temperature of No. three high-pressure heater outlet feedwater to calculate high-pressure heater outlet Enthalpy of Feed Water H No. three _f3, utilize one-level extraction pressure and the temperature computation one-level enthalpy H that draws gas _c1, utilize secondary extraction pressure and the temperature computation secondary enthalpy H that draws gas _c2; Utilize H _f1and H _f3calculate a high-pressure heater and No. two high-pressure heater feedwater caloric receptivity summation h ₃, utilize H _c1and H _c2calculate the secondary thermal discharge q that draws gas ₂;

Extraction flow computing unit, for utilizing feedwater flow D _fw, a high-pressure heater and No. two high-pressure heaters feedwater caloric receptivity summation h ₃with the secondary thermal discharge q that draws gas ₂, calculate first order extraction flow D ₁with second level extraction flow D ₂sum;

Flow exact value computing unit, for utilizing first order extraction flow D ₁with second level extraction flow D ₂sum is calculated reheated steam flow exact value D _rj(t).

7. device according to claim 6, is characterized in that,

Duty parameter also comprises main steam flow D _s, regulate porthole door bar and shaft gland steam leakage D _l, hotter desuperheat spray flow D _j;

Flow exact value computing unit specifically utilizes formula

D _rj(t)=D _s-(D ₁+D ₂)-D _l+D _j。

Calculate reheated steam flow exact value D _rj(t).

8. according to the device described in claim 6 or 7, it is characterized in that,

Extraction flow computing unit specifically utilizes formula

$D_1+D_2=f\left(D_{\mathrm{fw}}\frac{h_3}{q_2}\right)$

Calculate first order extraction flow D ₁with second level extraction flow D ₂sum.

9. according to the device described in claim 6 or 7, it is characterized in that, also comprise flow dynamics value computing unit and information fusion unit, wherein:

Duty parameter also comprises intermediate pressure cylinder inlet steam pressure P, intermediate pressure cylinder inlet steam temperature T;

Flow dynamics value computing unit, for utilizing a grade front parameter

determine reheated steam flow dynamics value D _rf(t);

Information fusion unit, for by reheated steam flow exact value D _rjand reheated steam flow dynamics value D (t) _rf(t) carry out information fusion, to obtain final reheated steam flow soft measurement value D _r(t).

10. device according to claim 9, is characterized in that,

Information fusion unit specifically utilizes formula:

D _r(t)=D _rj(t)+F[D _rf(t)-D _rj(t)]

Calculate reheated steam flow soft measurement value D _r(t), wherein F is filter function, for suppressing D _rf(t) error producing when calculating steady state condition, so that reheated steam flow soft measurement value D _r(t) there is reheated steam flow exact value D simultaneously _rj(t) precision and reheated steam flow dynamics value D _rf(t) dynamic perfromance.

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