Summary of the invention
Technical matters to be solved by this invention is, not enough for prior art, provides a kind of extracting method of steam turbine power response characteristic parameter, to exert oneself power P to high pressure cylinder peak power
hPwith high pressure cylinder time to peak T
hPaccurately extract, avoid that artificial subjectivity of checking is strong, noise causes gained P
hPand T
hPthe lower problem of precision.
For solving the problems of the technologies described above, the technical solution adopted in the present invention is: a kind of extracting method of steam turbine power response characteristic parameter, and it is characterized in that, the method is:
1) data prediction: determine the initial time T that steam-turbine unit power changes
0with the initial power P of unit
0;
2) initial time T is got
0to T
0the data of the power of the assembling unit change curve in this time period of+△ T to be exerted oneself power P as extraction steam turbine high-pressure cylinder peak power
hPwith high pressure cylinder time to peak T
hPvalid data; Described power of the assembling unit change curve obtains according to steam turbine and regulating system parameter measured test thereof;
3) carry out fitting of a polynomial to the valid data of said extracted, obtaining fitting of a polynomial result is: P=f (t), and wherein t is time variable, and P represents the fitting power of change of corresponding time corresponding to t;
4) to P=f (t) differentiate, the derivative equation of fitting of a polynomial result is obtained
solve described derivative equation, obtain all solutions of described derivative equation;
5) high pressure cylinder peak power time T is determined
1: when described derivative equation a certain solution is greater than T
0+ △ T
1(△ T
1be a time regulatable interval, its value can adjust between 0.1s ~ 0.2s) minimum real solution time, then this root solution is high pressure cylinder peak power time T
1value;
6) high pressure cylinder peak power P is determined
1: according to T obtained above
1, according to time and power, the corresponding relation on power of the assembling unit change curve determines T
1time the power of the assembling unit value of inscribing, this value is high pressure cylinder peak power P
1numerical value;
7) calculate high pressure cylinder peak power to exert oneself power P
hP: according to described high pressure cylinder peak power P
1with initial power P
0calculate P
hP, P
hP=P
1-P
0;
8) high pressure cylinder time to peak T is calculated
hP: according to described high pressure cylinder peak power time T
1with initial time T
0calculate T
hP, T
hP=T
1-T
0.
Compared with prior art, the beneficial effect that the present invention has is: method of the present invention can be exerted oneself power P to high pressure cylinder peak power
hPwith high pressure cylinder time to peak T
hPaccurately extract, avoid that artificial subjectivity of checking is strong, noise causes gained P
hPand T
hPthe lower problem of precision; The computational accuracy of the inventive method is high, thus ensure that the accuracy and confidence of follow-up check.
Embodiment
As shown in Figure 1, the extracting method of one embodiment of the invention steam turbine power response characteristic parameter comprises the steps:
(1) data prediction:
(1.1) the initial time T that the power of the assembling unit changes is determined
0: according to the variation tendency determination initial time T of the frequency departure that steam turbine and regulating system parameter measured test thereof obtain
0, the time corresponding to frequency departure generation Spline smoothing is initial time T
0.
(1.2) the initial power P of unit is determined
0: power of the assembling unit change curve (as Fig. 2) can be obtained according to steam turbine and regulating system parameter measured test thereof, by power of the assembling unit change curve determination initial power P
0.Get initial time T in (1.1)
0on power of the assembling unit change curve before, the mean value of all data is as initial power P
0.
(2) valid data are selected: get initial time T
0to T
0the data of the power of the assembling unit change curve in this time period of+△ T are as extraction P
hPand T
hPvalid data.△ T is an adjustable time interval, and when △ T is too little, then the valid data comprised in selected data very little thus cannot to P
hPand T
hPeffectively extract; When △ T is excessive, then the invalid data comprised in selected data too much thus increase and extract P
hPand T
hPcalculated amount and error.From actual effect, it is comparatively suitable that △ T was taken between 1 ~ 3 second.
(3) fitting of a polynomial and derivative equation rooting thereof:
(3.1) fitting of a polynomial: according to the valid data selected by (2) joint, fitting of a polynomial is carried out to it.Polynomial order is selected between 8 ~ 12, when order less or larger time, all may reduce the fitting precision of fitting of a polynomial.T
0to T
0the curve of the polynomial fitting in this time period of+△ T accurately can reflect the trend of same time period internal power response change curve, this curve is a level and smooth curve thus eliminates the impact of noise simultaneously, the fitting of a polynomial result finally obtained is following form: P=f (t), in formula, t is time variable, and P represents the fitting power corresponding to corresponding time variable t.
(3.2) derivative equation rooting: get fitting of a polynomial result P=f (t) that (3.1) obtain, first carries out differentiate to it, namely has
thus obtain the derivative equation of fitting of a polynomial result
derivative equation is solved to all solutions finally obtaining equation.
(4) high pressure cylinder peak power time T is determined
1with high pressure cylinder peak power P
1
(4.1) high pressure cylinder peak power time T is determined
1: the high pressure cylinder peak power time be first sharp wave on power of the assembling unit change curve in (1.2) crest corresponding to time.Mathematically understand, this point is the Local Extremum of power of the assembling unit change curve, therefore T
1one of them that in (3.2), all of derivative equation is separated.All of derivative equation solution in search (3.2), when the root of one of them root is greater than T
0+ △ T
1(△ T
1be a time regulatable interval, its value can adjust between 0.1s ~ 0.2s) real number and minimum time, then the root of this root is high pressure cylinder peak power time T
1numerical value.
(4.2) high pressure cylinder peak power P is determined
1: according to obtained T
1, according to time and power, the corresponding relation on power of the assembling unit change curve determines T
1time the power of the assembling unit value of inscribing, this value is high pressure cylinder peak power P
1numerical value.
(5) calculate high pressure cylinder peak power to exert oneself power P
hPwith high pressure cylinder time to peak T
hP:
(5.1) calculate high pressure cylinder peak power to exert oneself power P
hP: the high pressure cylinder peak power P determined according to (4.2)
1(1.2) determined initial power P
0calculate P
hP, P
hP=P
1-P
0.
(5.2) high pressure cylinder time to peak T is calculated
hP: according to (4.1) determined high pressure cylinder peak power time T
1(1.1) determined initial time T
0calculate T
hP, T
hP=T
1-T
0.
Method of the present invention is described in detail below for a certain steam-turbine unit:
(1) data prediction:
(1.1) the initial time T that the power of the assembling unit changes is determined
0: the variation tendency (as shown in Figure 3) of the frequency departure obtained according to steam turbine and regulating system parameter measured test thereof determines initial time T
0, the time corresponding to frequency departure generation Spline smoothing is initial time T
0, now T
0=21.45s.
(1.2) the initial power P of unit is determined
0: power of the assembling unit change curve (as shown in Figure 4) can be obtained according to steam turbine and regulating system parameter measured test thereof, by power of the assembling unit change curve determination initial power P
0.Get initial time T
0(T
0=21.45s) before power of the assembling unit change curve on the mean value of all data as initial power P
0, now P
0=496.74MW.
(2) valid data are selected: make △ T=1s, get initial time T
0to T
0the data of the power of the assembling unit change curve (as shown in Figure 2) in this time period of+△ T are as extraction P
hPand T
hPvalid data.
(3) fitting of a polynomial and derivative equation rooting thereof:
(3.1) fitting of a polynomial: according to the valid data (as shown in Figure 3) selected by (2) joint, fitting of a polynomial is carried out to it.Polynomial order is chosen as 8, and the fitting of a polynomial result finally obtained is following form:
P=f(t)=-8.8994t
8+849.6632t
7-1.0329e4t
6-1.9652e6t
5+1.2043e8t
4-3.2852e9t
3
4.8921e10t
2-3.8760e11t+1.2854e12, in formula, t is time variable, and P represents the fitting power corresponding to corresponding time variable t, based on this polynomial fitting matched curve as shown in Figure 5.
(3.2) derivative equation rooting: get fitting of a polynomial result P=f (t) that (3.1) obtain, first carries out differentiate to it, namely has
thus obtain the derivative equation of fitting of a polynomial result
derivative equation is solved to all solutions finally obtaining equation, its root solution set=-48.3464,22.767,22.4861,22.1719,21.4859 ± 0.1309i, 21.4894}.
(4) high pressure cylinder peak power time T is determined
1with high pressure cylinder peak power P
1
(4.1) high pressure cylinder peak power time T is determined
1: the high pressure cylinder peak power time be first sharp wave on power of the assembling unit change curve in (1.2) crest corresponding to time.Mathematically understand, this point is the Local Extremum of power of the assembling unit change curve, therefore T
1one of them that in (3.2), all of derivative equation is separated.All of derivative equation solution in search (3.2), when the root of one of them root is greater than T
0+ △ T
1(make △ T
1=0.2s, △ T
1be a time regulatable interval, its value can adjust between 0.1s ~ 0.2s) real number and minimum time, then the root of this root is high pressure cylinder peak power time T
1numerical value, now T
1=22.1719s.
(4.2) high pressure cylinder peak power P is determined
1: according to obtained T
1, according to time and power, the corresponding relation on power of the assembling unit change curve (as shown in Figure 6) determines T
1time the power of the assembling unit value of inscribing, this value is high pressure cylinder peak power P
1numerical value, now P
1=516.7MW.
(5) calculate high pressure cylinder peak power to exert oneself power P
hPwith high pressure cylinder time to peak T
hP:
(5.1) calculate high pressure cylinder peak power to exert oneself power P
hP: the high pressure cylinder peak power P determined according to (4.2)
1(1.2) determined initial power P
0calculate P
hP, P
hP=P
1-P
0=516.7MW-496.74MW=19.96MW.
(5.2) high pressure cylinder time to peak T is calculated
hP: according to (4.1) determined high pressure cylinder peak power time T
1(1.1) determined initial time T
0calculate T
hP, T
hP=T
1-T
0=22.1719s-21.45s=0.7219s.