JPS62240402A - Shortest starting method for thermal power plant - Google Patents

Abstract

PURPOSE:To shorten a starting time, by a method wherein simulation is effected by starting schedule optimization function by using plant dynamic characteristics prediction function, and each ventilation time, shortening a time between centilation of an intermediate pressure and ventilation of a high pressure turbine to a minimum value, is determined. CONSTITUTION:During the starting of a thermal power plant, a starting schedule time relating to control necessary to the starting and setting of a control desired value is prepared by starting schedule executing function 1000, and according to an output therefrom, a plant 3000 is started by means of schedule execution function 2000. In this starting method, the starting schedule preparing function 2000 is provided with schedule optimization function 1100 and plant dynamic prediction function 1200. Simulation is effected by the optimization 1100 by using the plant dynamic prediction function to determine each ventilation time, optimizing a time between ventilation of an intermediate pressure turbine and ventilation of a high pressure turbine, and the result is outputted to the schedule execution function 2000.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an L & short startup method for a thermal power plant that adopts an intermediate-pressure turbine advance startup method and a metal match control method, and particularly relates to a method for starting a thermal power plant that adopts an intermediate-pressure turbine advance startup method and a metal match control method, and particularly relates to a boiler temperature rise that differs at each startup. Concerning the shortest startup method to flexibly accept characteristics and start the turbine in the shortest time necessary 6 [Prior technology] Starting a thermal power plant! ! The conventional method for ls is
Depending on the stop time before startup and the temperature state of the equipment, the initial amount of fuel input to the boiler, the time function of main steam temperature and pressure rise,
This is a method in which the time function of turbine speed increase and load increase is determined as an 8vJ schedule, and this startup schedule is executed by a control system provided in each system of the plant. This most typical method is described in [Electrical World (February I Q6fi), pages 58 to 62 (I
El, electrica L World, Vol, 16
5, Nu 6) paper “Therma 1S
stress 1: nfluence Starti
ng, I, oadi, ng of Rolfr
s.

Turbines”.

This method is a method that uniquely determines the startup schedule based on the initial state of a limited portion of the plant. That is, the steam turbine speed increase rate, initial load amount, speed maintenance, steam turbine warm-up time by load maintenance, and load change rate are determined according to the initial values of boiler steam pressure, boiler outlet steam temperature, and steam turbine casing temperature. This is the way to do it. Here, variations in the temperature increase characteristics of boiler-generated steam are absorbed as a margin for the startup schedule, so the created startup schedule tends to be longer than necessary.

Another conventional method is U.S. Patent No. 3.446,
No. 224 and No. 4,228,359 are known.

These methods attempt to quickly start up a steam turbine while monitoring the thermal stress generated in the steam turbine online in real time, but, like the conventional methods described above, there is no mention of a method for starting the boiler.

Conventional methods aimed at shortening boiler startup time include:
Japanese Unexamined Patent Publication No. 157402/1984 is known. This method attempts to rapidly raise the temperature of the steam generated by the boiler while monitoring the thermal stress generated in the boiler online in real time. However, this method makes no mention of starting the turbine.

In addition, a method has been proposed in which a turbine bypass system is installed and an intermediate-pressure turbine is started using this system (Japanese Patent Application No. 1983).
-169166). This method ventilates the intermediate pressure turbine under the condition that a predetermined metal match condition is met.
The speed has increased at a predetermined speed increase rate. However, since the temperature increase characteristics of the boiler differ each time the boiler is started, a large margin is set in the speed increase rate to account for this variation, so the speed increase using the intermediate pressure turbine tends to take longer than necessary. Therefore, the ventilation of the high-pressure turbine after the completion of speed-up is delayed compared to the temperature rise of the boiler, which may cause thermal shock to the high-pressure turbine, or in the worst case, miss the opportunity for metal matching, resulting in startup failure. There is.

[Problem that the invention seeks to solve]

As described above, all of the conventional methods are rapid startup methods that focus on only one side of the boiler or steam turbine. However, even if these individual methods are combined,
Plan I - There is no guarantee that the overall start-up time will be the shortest, because the boiler and the steam turbine have extremely strong mutual interference, and individual optimization does not necessarily result in overall optimization.

The object of the present invention is to provide a solution to a boiler or a steam turbine, whereas the conventional method described above targets either a boiler or a steam turbine.

By comprehensively considering the startup characteristics of both, we aim to minimize the startup time of the entire plant, and by providing the shortest startup method for thermal power plants that is effective in plants that use the intermediate-pressure turbine advance startup method. be.

[Means for solving problems]

The purpose of Section L is to focus on the start-up characteristics of the entire plant system, which were not considered in the conventional method, and to predict these start-up characteristics.
This can be achieved by accurately calculating the metal match conditions using a model for the second phase and determining the optimal ventilation timing for the intermediate-pressure turbine and high-pressure turbine.

[Effect]

The lower limit value of the reheat steam ventilation temperature is calculated from the metal temperature of the intermediate pressure turbine, and when the actual reheat steam temperature becomes higher than this, the intermediate pressure turbine is ventilated and the speed is increased. After completing the speed increase, calculate the main steam ventilation temperature lower limit from the metal temperature of the high pressure turbine, and assume that when the actual main steam temperature becomes higher than this, the high pressure turbine is vented and the initial load is applied. Then, the turbine generated stress is predicted using a plant dynamic characteristics prediction model. It is determined whether or not this stress is below the allowable value. If it is predicted to be below the allowable value, ventilation and load addition are actually carried out, and if it is predicted to be above the allowable value, no ventilation is carried out. Maintain load operation status. In this case, the conditions for allowing ventilation to be determined again after a certain period of time are determined using the above method, and if the predicted stress is less than the allowable value, ventilation and loading are actually carried out.

According to such a procedure, metal matching can be performed ideally, and startup time can be significantly shortened.

[Embodiments of the invention]

FIG. 1 shows the basic functional configuration of the quickest starting method for a thermal power plant according to the present invention. Broadly speaking, the functions include a startup schedule creation function 1000 and a schedule execution function 2000. The former creates an optimal startup schedule 101 that minimizes the plant startup time, and the latter changes the manipulated variable 201 for the plant from time to time in order to start the actual plant 3000 according to the optimal startup schedule.

Startup schedule creation function 1. OOO also has a schedule optimization function ttoo and a plant dynamic characteristics prediction function 1'
Consisting of 200. The former also has offline optimization function 11
10 and an online optimization function 1120, the latter further comprising a plant dynamic characteristic model 1210° and a boiler stress calculation function 1220. and turbine stress calculation function] 230. The offline optimization function 1110 assumes a startup schedule 111 and converts it into a plant dynamic characteristic model 1210.
By setting the startup characteristics (213, 211, 21
2), and the boiler stress calculation function 1220 and the turbine stress calculation function 1230 calculate the boiler stress 221 and the turbine stress 231, respectively. On the other hand, the online optimization function 1120 uses the plant dynamic characteristic model 1
2) When O operates, the target operating state 121 of the turbine is successively optimized according to the turbine stress 231. The offline optimization function 1110 evaluates the behavior of process variables related to the operational limit conditions calculated as a result and the required startup time, assumes a new startup schedule 111, and sets this in the plant dynamic characteristic model 1210. By repeating the process described above, an optimal startup schedule 101 that can complete startup in the shortest time without causing the process state to violate operational restrictions is determined. The determined optimal startup schedule 101 is set in the schedule execution function 2000 and becomes a target value for actually starting the plant 3000. Here, the plant dynamic characteristic model 1210° boiler stress calculation function 1220. and turbine stress calculation function 12
30 requires initial values 321, 322, and 323, respectively, which are process state values measured before startup.

Next, a parameter 1 defining the startup schedule in the embodiment will be defined. Because the plant start-up time basically depends on the temperature characteristics of the plant.

Parameters that have a strong causal relationship with the temperature increase characteristics of the plant should be selected. Based on this basic idea, the igniter firing interval (TraL mill starting interval (
Four parameters were selected: TPLV), main steam temperature rise rate (■, TMS), and reheat steam temperature rise rate (TRH)1).

The igniter ignition interval (Tta) is the interval at which, when a boiler ignition command is issued, the igniters corresponding to each burner stage of the boiler are ignited one after another at time intervals Tro, and the light oil purse is ignited.

The mill starting interval (Tpt,v) is the time interval when the pulverized coal mills are sequentially started after all the light oil burners are ignited. In this case, the mills up to the second mill supply pulverized coal at 50% of the rated flow rate according to operational standards. 3
When the second mill is started.

The total flow rate of pulverized coal fed into the boiler is 40% of the rated value (
Each mill is operated so that its share is 67%. Thereafter, when the turbine is started and the generator output reaches 40%, the mode shifts to 1 normal load operation mode, and the mills are started according to the load request, and up to 5 mills are operated. As each mill is started up, the light oil burner is extinguished.

The main steam temperature rise rate (Ltgs) is the normal load operation area (
This is a parameter that determines the rate of increase in main steam temperature at a load of 40% to 100%.
It has the function shown in the following formula for the main steam temperature target value TMSS calculated by .

......(1) Here, 7MS40: Main steam temperature when 40% load is reached ('C) TMSR: Main steam temperature rated value ('C) L: Load (%) In other words, load increase , TMS (%) means that the main steam temperature reaches the rated value.

The reheat steam temperature increase rate (I, TRH) is a parameter that defines the rate of increase in reheat steam temperature in the normal load operation region, similar to the main steam temperature, and is a parameter that defines the rate of increase in reheat steam temperature in the normal load operation region.
Reheat steam temperature target value Tr+usI calculated as 00! t
It has the function shown in the linear equation for .

・・・・・・(2) Here, TRH40: Reheat steam temperature ('C) when 40% load is reached TFIHR: Reheat steam temperature rated value (℃) L: Load (%
) That is, it means that the reheat steam temperature reaches the rated value when the load reaches T, TRI (%).

Next, the 1gt optimization algorithm in the offline optimization function 1110 will be described in detail.

FIG. 2 shows the basic processing procedure of the startup schedule I & optimization algorithm 11 to which the complex method, which is one of the nonlinear optimization techniques, is applied to the present invention. Here, the schedule parameters are: X= [X(1), X(2), X(3), X(4))'
= [T ta, Tp+, v+ Lt
Mst Ltno) '・・・・・・(3) Each processing function will be explained below.

(1) Initialization 100 FIG. 33 shows the symbols, values, units, and meanings of constants and initial values used in the optimization algorithm. Enter these values during initialization.

(2) Initial simplex formation 200 The processing procedure is shown in FIG. The design value X is set at the initial trial point Xi.
Set o and run the simulation. What is simulation in this case? Plant dynamic characteristics prediction function 1200
The purpose is to predict startup characteristics when the plant is started up according to the startup schedule XD. At this time, if the operation limiting factor Y (NMI/) for Xn does not violate the implicit constraint Yt, (v on N) (see Figure 5), an initial simplex is formed near Xs according to the following equation. .

Here, RJ is a pseudo-random number satisfying -1, ≦-R, +<1, and is determined by the procedure shown in FIG. If XJ violates the implicit constraint, the trial point is corrected according to the procedure shown in FIG.

(a) Random number generation 220 Figure 6 shows the procedure for calculating pseudo-random numbers with M as a variable. 0 This algorithm is a method that uses the fifth cursed number from the highest digit of the square root. 7 (b) Initial simplex correction 240 Trial point X (LJ
) is modified as in Kinshiki.

X(1,J)=X(I,J)+(LD(1)(XM
^x(I)-XHTN(ding))...
- (5) (c) Extension magnification correction coefficient determination 260 The sensitivity to operation limiting factors when operating parameters are changed is large, as shown in FIG.

There are various types such as medium, small, and zero. Therefore, it is thought that modifying the trial point extension magnification depending on which driving limiting factor violates the implicit constraint condition (see Figure 5) will improve the efficiency of searching for the optimal value than uniformly modifying it. It will be done. FIG. 9 shows an algorithm for determining the extension magnification correction coefficient based on the implicit constraint monitoring algorithm (see FIG. 10) according to this idea.

(3) Characteristic evaluation ranking 300 As shown in FIG.
) is an algorithm for determining the following three characteristic points among the vertices of a simplex consisting of:

(j) Best vertex (XQ, TXre) The operation parameter (Xs
) and activation time (T'x + Q) (11) Worst vertex (Xs + Tx, s) The operation parameter (X
s) and startup time (T x + s ) (iii) second worst vertex (Xsz, Txys
z) Operation parameter (XSZ) and startup time (T x,
5z) (4) Center of gravity calculation 400 As shown in Figure 12, excluding the worst vertex Xs<K-1)
Geometric centroid coordinates x of a simplex consisting of vertices
Find O.

(5) New trial point determination 500 As shown in FIG. 13, the new trial point is defined as Xx+t with coordinates that satisfy the following equation. This point is on the straight line connecting the worst vertex XS and the center of gravity Xi, and the distance from the center of gravity is R(XG-
Xs). Here, R is the extension magnification described in (7) 6 X*+t =Xa +R(Xa -Xs) ・-
...(6) However, XMIN < Instead, as shown in Figure 14, when R<-0, IRo, the regression is stopped, the entire simplex is degenerated, and a new search direction is found.This degeneration method is explained in (9). do.

(7) Extension magnification correction 700 If the implicit constraint condition is violated, the extension magnification R is corrected by the method shown in FIG.

(8) New trial point extension 800 At the new trial point XK+1, the startup time Tχ is +1,
The shortest time up to that point is Tx1. If it is shorter than the 16th
As shown in the figure, it is further extended in the same direction to approach the optimal point. Let this re-extension point be XE.

(9) Trial point regression 900 If the startup time TX,+1 at the new trial point XK order 1 is longer than the second longest time Tx,sz up to that point, there is a possibility that XK+1 has jumped over the optimal point.

Therefore, as shown in FIG.
In the case of
If ÷s > T x e s, TX is caused to retreat significantly (R = −0, 5). The trial point at this time is assumed to be Xc.

(10) Simplex degeneracy 1300 When no characteristic improvement point is found on the straight line connecting the worst point Xs and the center of gravity Xa (
If there is no Xc such that T x g c < T x e s), the possibility of approaching the optimal point is newly found by reducing the size of the simplex in the direction of the optimal point Xe. In this case, as shown in FIG. 18, the degeneracy rate is initially set to 1/2, but if each vertex violates the constraint conditions, the degeneracy rate is set to 3/4. Vertices that still violate the constraints are returned to their original positions. Here, the explicit constraints are the upper and lower limits of the optimization parameters themselves, and each
＾＾, XnxN. As shown in FIG. 19, the simulation is executed after confirming that all parameters satisfy the explicit constraints.

(1t) I & negative points excluded 14201440.146
0 As shown in FIG. 20, I2. If Xx+t or XC is improved over Xs, exclude Xs,
+1 to XE, X. Alternatively, add Xc to form a new simplex.

(I2) Judgment of reaching the limit on the number of searches 150° The number of searches is the number of simulations, and by limiting this, the present algorithm is prevented from falling into an infinite loop. FIG. 21 shows the processing procedure for this purpose, and the meanings of the symbols are as follows.

NT2 Total number of simulations AD: Number of times a simulation result was used as a vertex of a simplex NN (1: Number of times a simulation result was not used as a vertex of a simplex NKAD: Number of times XK+1 was used as a vertex of a simplex NEAD: XIE NcAn: Number of times Xc was used as a vertex of a simplex NcAn: Number of times Xc was used as a vertex of a simplex NRAD Number of times the simulation result for simplex degeneracy was used as a vertex of a simplex NKNo: +1 to X was used as a vertex of a simplex NI!sa: Number of times XF! was not used as a vertex of a simplex NcNo: Number of times Xc was not used as a vertex of a simplex NgNa Number of times the simulation result for simplex degeneracy was not used as a vertex of a simplex (13) Simulation 1600 The basic procedure of the simulation is shown in Figure 2z.In the simulation, the plant startup process was divided into three phases: boiler startup, speed increase, and load increase.The boiler startup phase starts from igniter ignition. Pressure increase control (this function is built into the plant dynamic characteristic model) is executed to set the startup pressure (94.9 ata for main steam, 8 ata for reheat steam pressure).
, 16ata), and the speed increase phase indicates the startup process until the metal match control function including the speed increase control function increases the speed to the rated speed and the metal match condition of the high pressure turbine is satisfied. .

The load increase phase indicates a startup process in which a load is added by the addition condition determination function and the load increase control function reaches the rated load (target load in actual operation).

(14) Optimum point convergence judgment 17oO The optimal point, that is, the shortest startup schedule satisfies the following equation
, Q.

Xe at this time is expressed as X1) PT.

This completes the detailed explanation of offline optimization function 11]0.

Next, the online optimization function 1120 will be explained in detail.

In order to achieve rapid startup through online optimization, we focused on the following points.

(1) Rapid boost considering drum steam temperature change rate An increase in main steam pressure means an increase in drum pressure.

An increase in drum pressure manifests itself as an increase in saturation temperature determined by pressure. Additionally, changes in drum steam temperature create thermal stresses in the drum. In order to keep this drum thermal stress below an allowable value, it is necessary to keep the rate of change in steam temperature below an allowable value. In the present invention, in consideration of the fact that the relationship between pressure and saturation temperature is non-linear, a method is adopted in which the target pressure is determined so that the maximum allowable rate of temperature change is always achieved. This minimizes the time required for boosting.

(2) The plant, which is subject to increased ventilation control by calculating the optimum metal match conditions, was started at medium pressure (method of increasing speed using an intermediate pressure turbine). For metal match conditions, it is necessary to consider both the high-pressure turbine and the intermediate-pressure turbine. In the present invention, when the reheated steam temperature reaches the ventilable temperature determined from the metal temperature of the intermediate pressure turbine, the intermediate pressure turbine is immediately ventilated to increase the speed. When the speed increase is completed and the main steam temperature reaches the ventilation temperature determined from the high pressure turbine metal temperature,
Control immediately advances to the load increase phase.

This keeps the turbine ventilation waiting time to the necessary minimum.

(3) Stress (thermal stress + centrifugal stress) generated on the rotor surface and bore of the rapidly increasing intermediate-pressure turbine, taking into account the stress of the intermediate-pressure turbine, is kept below the allowable value.

By sequentially determining the maximum acceleration rate, the speed increase can be completed in the shortest possible time.

(4) Early annexation based on determination of conditions for annexation Immediately after annexation, the boiler-generated steam temperature rises rapidly.

If this phenomenon is not taken into account and included only by establishing metal match conditions for the high-pressure turbine, excessive thermal stress will occur in the rotor despite the load being maintained. Therefore, in the present invention, the generated stress is predicted using a plant model, and if the stress is below the allowable value, load addition is performed, and if the stress is above the allowable value, the stress is awaited. This minimizes the waiting time for merging and shortens the startup time.

(5) Rapid load increase considering the stress of high-pressure and intermediate-pressure turbines Suppress the stress (thermal stress + centrifugal stress) generated on the rotor surface and bore of high-pressure and intermediate-pressure turbines to below allowable values, and reduce the maximum load increase rate. By making sequential decisions, the load increase can be completed in the shortest possible time.

The processing method of the online optimization function 1120 created based on the basic idea described above will be described in detail.

(1) Thermal stress occurs in the drum of the boiler at the time of startup of the boost control plant as the temperature of the internal fluid changes. In order to prevent the occurrence of extremely large thermal stress at this time, the rate of change in internal fluid temperature must be suppressed to a permissible value or less.

Since the internal fluid temperature is considered to be the saturation temperature uniquely determined by the pressure at that time, the allowable temperature change rate can be expressed by the allowable pressure change rate. As shown in FIG. 23, the relationship 1123 between pressure P and saturation temperature TSAT is nonlinear.

Now, if the set α(P) of the saturation temperature change rate at pressure P is written as and the saturation temperature change rate allowable value is αL, then the allowable pressure change rate β(P) 11.24 at pressure P is... ...(9) A characteristic curve shown in FIG. 24 is obtained.

This characteristic indicates that the higher the pressure level, the greater the allowable rate of pressure change. The control system block diagram 11 shown in Fig. 25 takes advantage of this feature in boost control.
It is 25.

(2) Metal match control 1610 The basic processing procedure of metal match control is shown in FIG. This plant uses an intermediate pressure turbine startup method, so
Reheat steam temperature TRI
ve Max), it means that the metal match condition has been established, and the speed can be increased by the intermediate pressure turbine. If it is low, wait for the temperature to rise.

However, the main steam temperature TMS at the time when the metal match condition is established is THMcop (the value obtained by converting the metal match condition upper limit temperature of the high pressure turbine to the main steam temperature, hereinafter,
If the temperature is higher than Po5jtive Max (for the high-pressure turbine), the temperature of the main steam has risen too quickly, and it is impossible to increase the load by ventilating the high-pressure turbine.
Speed increase using an intermediate pressure turbine is no longer meaningful. That is,
Metal Matsushi was a failure. Also, during acceleration, TMs>TM
M(!UP) is also a metal match failure.

S is THHC in the main steam temperature T after completion of speed increase! IN (This is the value obtained by converting the metal match condition limit temperature of the high-pressure turbine into the main steam temperature. Hereinafter, the negative value for the high-pressure turbine
(referred to as tive Max), the main steam temperature must be raised. Then T ss > T MMC)I
If the metal match condition is established, the process moves to the condition determination function that allows the addition of the load increase phase.

If you are stuck waiting for the metal match condition to be established after completing the speed increase, limit the simulation time (TLtMrT
) L/, is considered a startup failure. Due to this.

Save simulation calculation time.

Next, the means for calculating the metal match condition will be explained.

(1) Negat, iva Ma for intermediate pressure turbine
x value (TRMCHN) 1611 Figure 27 shows the reheat steam temperature Ne for the intermediate pressure turbine.
In this example, the metal match lower limit temperature TFIsMrN of the steam temperature in the medium-pressure turbine ball during ventilation is set to a value 50° C. lower than the ball temperature Trio.

The process shown in the figure is for calculating the reheating steam temperature Tus+u* such that the steam temperature in the ball becomes TR8MIN. This process uses the calculation routine included in the turbine stress calculation function 3-230 (a method for calculating the steam temperature in the bowl from the reheated steam temperature), and conversely calculates TRMcIIN from TnsHIN through convergence calculation.

(it) Po5itive M for high pressure turbine
ax value (T+4tc F+p) 1 6 1
2 Figure 28 shows the Is air temperature P for the high pressure turbine.
The procedure for calculating the o5itive Max value (TMMcup) is shown. In this example, the metal match upper limit temperature TMSM^X of the steam temperature after the first stage of the high-pressure turbine during ventilation is set to a value 50° C. higher than the rotor surface temperature (which is considered to be equal to the casing inner wall temperature). The process shown in the figure is for calculating the main steam temperature TMMCHP such that the first post-death steam temperature becomes THsM^X.As in the previous section, this process is also a calculation included in the turbine stress calculation function 1230. By sharing the routine (method of calculating the first post-cooling steam temperature from the main steam temperature), convergence calculation is used to conversely calculate TMsM.
Negat, ive for the 6 (ti+) high pressure turbine using the method of calculating TxHcnp from ^X
Max value (TMMCHN) 1613 Figure 29 shows the main steam temperature Neg for the high pressure turbine.
The procedure for calculating the at,ive Max value (TMM(!HN) is shown below. This processing procedure is exactly the same as the previous section, and the main steam temperature T
This is to find the MMCHN.

(3) Speed-up control 1640 FIG. 30 shows the processing procedure of speed-up control. The characteristics of this processing are as follows.

(i) By predicting the stress generated in the intermediate pressure turbine and sequentially determining the maximum speed increase rate at which the predicted value is less than or equal to the allowable value, the turbine can be started with a speed increase pattern that provides the shortest speed increase time.

(ii) To improve the accuracy of stress prediction, use the plant model as is for prediction.

In this method, the reference time TRHMIl! o to TNVAR
Assuming that the speed is increased at the maximum speed increase rate DN (], ) between Y and then the speed is maintained, 1 time T tsF! o+Tsup
Predict the stress generated in the turbine up to As a result, if the predicted stress value is less than the allowable value at any point in time, the acceleration rate r)N(1) is reached at time T rsao + T N
Actual up to VARI/(as a startup simulation)
speed up. On the other hand, if the predicted value is greater than or equal to the allowable value, the acceleration rate DN (2), which is one rank lower, is set in the model.

Predict generated stress. Even in the case of ON (3), if the predicted stress value does not fall below the allowable value, DN (4) is set to maintain the speed. In this way, time T r
MI! When O+T NVARY is reached, this time is again set as the reference time TTMI! Place it as O and perform the same process. By repeating the above process, when the rated speed is reached, the speed increase control is completed and the process for the next combinable condition is performed.

(4) Judgment of combinable conditions 1620 FIG. 31 shows the processing procedure for determining combinable conditions. The contents of this process can be broadly divided into the following two types, as shown by the broken line in the same figure.
Consists of one.

(i) Predicting the state after addition The stress generated after applying the initial load (T, = 3%) is predicted using the plant model, and this is the entire prediction interval TxL.
In this step, it is determined whether or not the value is below the allowable value. If it is below the allowable value, load addition is performed.

(ii) Waiting for addition conditions If the prediction result in the previous section is negative (if the predicted stress is greater than or equal to the allowable value), no load addition is performed and no-load operation is continued at control cycle Tc5 (state prediction is then performed). wait until During this period, if the main steam temperature T'T4s exceeds the upper limit temperature TMMCHP of the metal match condition for the high pressure turbine, the metal match has failed and the startup has failed.

If the metal match does not fail, the process returns to step (i) again in the fifth control cycle to predict the state after the merging. If the conditions for parallel use are satisfied, the process moves to the next load increase control.

(5) Load-rise control 1630 FIG. 32 shows a processing procedure for load increase control.

This control method is basically the same as the acceleration control method. In this method, it is assumed that the load is increased at the maximum load change rate DN (1) between reference time TrMao and T LVARY, and that the load is maintained after that, and the time T r Hea + T
Predict the stress generated in the turbine up to LυP. As a result, if the stress predetermined value is below the allowable value at any time, the load change rate r)N(1) is determined at time TRHME.
The load actually increases (as a startup simulation) until O+TLVARY. Conversely, if the predicted value is equal to or greater than the allowable value, the load change rate DI, (2) one rank lower, is set in the model to predict the generated stress.

Even in the case of r)L(3), if the predicted stress value does not fall below the allowable value, set r)L(4) to maintain the load. In this way, the time T! is the next control period!
Ail! When o + T +vvAnv is reached, this time is again set as the reference time T■I! When the target load is reached by repeating 0 or more similar processes, starting is completed.

As shown in E below, the startup time required from boiler ignition to reaching the target load is defined as Tx.

〔Effect of the invention〕

According to the present invention, the plant start-up time, particularly the time from intermediate pressure turbine ventilation to high pressure turbine ventilation and load addition, can be significantly shortened. Does this affect the power grid? This not only improves the stability of the power supply, but also reduces the startup loss associated with the shortening of startup time in each power plant, ensuring reliable startup without metal match failures. The system is expected to have significant effects, such as improving the utilization rate and reducing the burden on operators.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the basic functional configuration of an embodiment of the shortest startup method for a thermal power plant according to the present invention, and FIG. 2 is a diagram showing the basic processing procedure of a startup schedule optimization algorithm to which the complex method is applied to the present invention. , Fig. 3 is a diagram showing the meaning of the initial values used in the processing procedure of Fig. 2, Fig. 4 is a diagram showing the processing procedure of initial simplex formation, Fig. 5 is a diagram showing operation limiting factors, and Fig. Figure 7 is a diagram showing the procedure for determining pseudo-random numbers, Figure 7 is a diagram showing the procedure for correcting trial points, Figure 8 is a diagram showing sensitivity to driving restriction requirements, Figure 9 is a diagram showing the procedure for determining a pseudo-random number.
The figure shows algorithm 11 for determining the extension magnification correction coefficient, Fig. 10 shows the implicit constraint monitoring algorithm, and Fig. 1J shows how to determine three characteristic points among the vertices of the simplex. Figure 1 showing algorithm 11 of
Figure 2 is a diagram showing the procedure for determining the geometric center of gravity coordinates of a simplex consisting of vertices excluding the worst point, Figure 13 is a diagram showing the procedure for determining a new trial point, and Figure 14 is a diagram showing the procedure for determining whether a trial point cannot be retreated. Figure 5 shows the extension magnification correction procedure, Figure 16 shows the new trial point extension procedure, Figure 17 shows the trial point regression procedure, and Figure 18 shows the simplex reduction procedure. Figure 19 is a diagram showing the procedure for determining the success or failure of explicit constraint conditions, Figure 20 is a diagram showing the procedure for excluding the worst point, Figure 21 is a diagram showing the procedure for determining whether the search limit has been reached, and Figure 22 is a diagram showing the procedure for determining whether the explicit constraint condition is successful or not. Figure 23 shows the basic procedure of simulation.
Figure 24 shows the relationship between pressure and saturation temperature, Figure 24 shows the relationship between pressure and allowable pressure change rate, Figure 25 is a block diagram of the boost control system, and Figure 26 shows the basic processing of metal match control. Figure 27 is a diagram showing the procedure for calculating the Negative Max value of the reheat steam temperature for the intermediate pressure turbine, and Figure 28 is a diagram showing the procedure for calculating the Po5i and tjve Max values of the main steam temperature for the high pressure turbine. , Figure 29 shows the main steam temperature Nega for the high pressure turbine.
FIG. 30 is a diagram showing the procedure for calculating the tive Max value, FIG. 30 is a diagram showing the procedure for increasing speed control, FIG. 31 is a diagram showing the procedure for determining conditions that allow for combination, and FIG. 32 is a diagram showing the procedure for load increase control. FIG. 101...Optimal startup schedule, 1.1-]...
・Start schedule, 121...Target operating state, 20
1... Manipulated amount, 21.1, 212, 213... Starting characteristics, 221... Boiler stress, 231... Turbine stress, 310... Plant parameters, 320, 32
1,322°: (23...Plant parameter initial value, 1000...Start schedule creation function, 1100
...Schedule optimization function, 111.0...Offline optimization function, 1]20...Online optimization function, 1200...Plant dynamic characteristic child fll11 function,
1210...Plant characteristic model, '12.20.
... Boiler stress calculation function, 1230 ... Turbine stress calculation function, 2000 ... Schedule execution function, 30
00...Plant.

Claims (1)

[Claims] 1. Operation and control target values necessary for starting a thermal power plant in which the intermediate-pressure turbine is ventilated before the high-pressure turbine, the speed of the turbine and generator is increased, and then the high-pressure turbine is ventilated. In the shortest startup method for a thermal power plant, which includes a startup schedule creation function that creates a temporal startup schedule related to settings, and a schedule execution function that actually starts the plant according to the created startup schedule, the startup schedule creation function It has an optimization function and a plant dynamic characteristics prediction function, and the schedule optimization function searches for a schedule that minimizes startup time, and the plant dynamic characteristics prediction function, which has a built-in dynamic characteristics model and stress calculation function, searches for the schedule that minimizes the startup time. The process state values at start-up predicted by stress calculation are output to the schedule optimization function, and the schedule optimization function performs a simulation using the plant dynamic characteristics prediction function to determine the flow rate from the ventilation of the medium-pressure turbine to that of the high-pressure turbine. 1. A method for starting up a thermal power plant in the shortest possible time, characterized in that each ventilation time that minimizes the time until ventilation is determined and outputted to the schedule execution function. 2. In the shortest startup method for a thermal power plant according to claim 1, the reheat steam temperature T_R_H is set to the metal match lower limit temperature of the intermediate pressure turbine predicted by the plant dynamic characteristics prediction function to the reheat steam temperature. Converted value T_
If it is higher than R_M_C_H_N, the schedule execution function executes the speed increase by the intermediate pressure turbine, and if it is lower, it waits for the reheat steam temperature T_R_H to rise without increasing the speed, and the main steam temperature T_M_S after the completion of the speed increase is Value T_M_M obtained by converting the metal match condition limit temperature of the high-pressure turbine predicted by the plant dynamic characteristics prediction function into main steam temperature
If it is higher than _C_H_N, the plant dynamic characteristic prediction function predicts the stress generated in the turbine assuming that the high-pressure turbine is ventilated and the initial load is applied, and the schedule optimization function predicts whether the stress will be below the allowable value. If it is below the allowable value, the schedule execution function executes load addition, and if it is predicted to be above the allowable value and the main steam temperature T_M_S is the converted value T_M_M_C_H_N.
A method for starting a thermal power plant in the shortest possible time, which is characterized by maintaining a no-load operation state without venting when the temperature is lower than .