JPH0116093B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an operation control device for a power generation plant composed of a plurality of power generation units.

[Technical background of the invention and its problems]

Recently, combined cycle power generation units have been developed and are being put into practical use with the aim of improving power generation efficiency.
This power generation unit combines a gas turbine and a steam turbine, and uses the exhaust gas that has driven the gas turbine to drive the steam turbine, thereby making effective use of thermal energy. However, since this power generation unit has a small single unit capacity, it is necessary to configure a single power generation plant with multiple units for system operation. Furthermore, since this power generation plant has only recently been developed, its operation control system has not been completely established, but it is expected that it will take a control form that is quite different from conventional ones. For example, since individual power generation units can be started and stopped easily, this power generation plant is used for operational control with a wide range of load adjustment.

Now, when operating such a power generation plant in a system, the number of operating power generation units is usually calculated based on the maximum capacity of the power generation unit and the minimum continuous operation load condition, and the power generation efficiency is determined according to the power plant load at that time. It is conceivable to determine the maximum value.

However, if the number of operating power generating units is determined using this method, the number of operating units may have to be changed in a short period of time.
The problem arises that the energy loss due to starting and stopping the power generation unit is greater, and that it is not possible to operate the power generation unit efficiently.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a power generation plant operation control device that can accurately determine the number of power generation units in operation so as to maximize operation efficiency, including start-up and stop losses, during load adjustment.

[Summary of the invention]

Therefore, when determining the number of power generation units in operation according to the load of the power generation plant, the present invention
The number of units to be operated is determined based on the magnitude of the loss by comparing the stoppage loss with the loss due to the reduction in power generation efficiency if the power generation unit is not started or stopped. However, when starting a stopped power generation unit, the predetermined operation The present invention is characterized in that the power generation unit to be started is determined in accordance with the priority order, and the start loss is determined by determining the stop time of the power generation unit.

[Embodiments of the invention]

FIG. 1 shows a system configuration diagram of a power plant operation control device for explaining the premise of the present invention. In the figure, 1 is a load control device, 2 is a process computer, and 3 is a data setting device. . This data setting device 3 is generally used for exchanging information between a human and a computer, and when a human gives commands, setting values, etc. to the computer, it is done through the setting device. The daily power plant load pattern set by the data setter 3 is input to the process computer 2 as a load pattern setting signal _S1 . The process computer 2 in the figure is connected to each power generation unit 4.
The entire power generation plant 5 is monitored and controlled based on the power generation unit operation monitoring control signal _S2 obtained from the power generation unit. That is, the process computer 2 monitors the operating status of each device in the power generation plant 5, performs many operations required to start and stop the power generation unit 4 in place of humans, and controls each control device and auxiliary equipment of the power generation unit. Outputs control command _S3 to. The load control device 1 controls the output load of the power generation unit, and according to the power generation plant target load given from the outside,
Performs output load control for the power generation unit during load operation. The power plant target load is generally set by a person or provided by the process computer 2. When setting a target load from the process computer 2, the target load signal is transmitted from the process computer 2 to the load control device 1 as a load control device monitoring control signal _S4 . In other words, humans can determine the daily power plant load pattern using the data setter 3.
By setting, the power generation plant load pattern is input to the process computer 2, and the process computer 2 performs start/stop control of the power generation unit according to the load pattern, and also processes the target load calculated based on the load pattern. The information is transmitted from the computer 2 to the load control device 1, and the load control device 1 controls the output loads of the power generation units 4 so that the total load of the power generation units 4 activated by the process computer 2 becomes the target load.

Figure 2 shows a functional block diagram of the process computer 2, where 20 is the maximum load signal for the power generation unit.
This is a power generation unit maximum and minimum load storage section that stores _S20 and a power generation unit minimum load signal ₂₁ .
The power generation unit maximum load signal S20 stored in advance in this storage section ₂₀ is determined from the rated capacity of the power generation unit 4, and the power generation unit minimum load signal _S21
is determined by steam turbine thermal stress and exhaust gas NOx pollution limit values.

21 is the power generation unit load efficiency curve parameter
This is a power generation unit load efficiency storage section that stores _S22 . The power generation unit load efficiency curve stored in advance in the storage section 21 is as shown in FIG.
This shows the efficiency of the power generation unit with respect to load changes from the minimum continuous operation load MINL to the maximum continuous operation load MAXL. As is clear from this figure, the efficiency of the power generation unit 4 increases as the output load of the power generation unit increases.

Reference numeral 22 denotes a power generation unit start-up/stop loss storage section that stores a power generation unit start-up/stop loss signal _S23 . The power generation unit start-up and stop losses stored in advance in the storage section 22 indicate the total amount of fuel, electric power, auxiliary steam, and make-up water consumed during the start-up and stop processes of the power generation unit 4.

Reference numeral 23 denotes an input processing section for applying the load pattern setting signal _S1 input from the data setting device 3 of FIG. The load pattern setting signal _S1 is set by the operator via the data setting device 3, and is as shown in FIG. That is, FIG. 4 shows an example of a daily load pattern curve, in which the horizontal axis represents the elapsed time of the day, and the vertical axis represents the power plant load. In the figure,
During the time periods _t0 to _t1 and _t3 to _t9 , there is little demand for electricity because it is late at night, and the power generation plant operates at a low load. Furthermore, from _t2 to _t3 and from _t6 to _t7 , the power demand is large due to factory operation, resulting in high load operation. Furthermore, t ₄ to _{t 5} represents a time when the load on the power generation plant decreases due to the lunch break.

The operating unit number calculation section 24 is a section that reads the signals S ₂₀ to S ₂₃ and S ₉ from each section described above and calculates the number of operating power generating units based on these signals. Reference numeral 25 denotes a target operating number storage unit that stores the target operating number signal S ₂₄ of power generation units calculated by the operating unit number calculation unit 24 in this manner.

With the above configuration, the target number of operating power generating units 4 is determined by the operating number calculating section 24 as shown in the flowchart of FIG. It is executed by computer 2.

That is, the operation number calculation unit 24 first reads the load pattern setting signal S ₁ via the input processing unit 23 (part A). As mentioned above, the load pattern setting signal S ₁ read by the operating unit number calculation unit 24 is, for example, the power generation plant load L _pi (L _p0 to L _p3 ) necessary to set the load pattern curve as shown in FIG. The load change time t _i (t ₀ to t ₉ ), etc.

Next, the operation number calculation unit 24 calculates the above set load.
L _pi (L _p0 to L _p3 ) and the maximum continuous operating load of the power generating unit obtained from the power generating unit maximum and minimum load storage section 20
Based on MAXL, the above set load L _pi (L _p0
The number of operating power generation units n _i (n ₀ to n ₃ ) with the highest power generation efficiency corresponding to ˜L _p3 ) is calculated using the following formula (Part A).

n _i = [L _pi /MAXL] Rounded up to decimals... (1) Next, the number of operating units calculation unit 24 calculates whether the number of operating units corresponding to each set load calculated by the above formula (1) satisfies the following formula. Determine whether or not (Part C).

n ₁ < min (n ₀ , n ₂ ) ... (2) Equation (2) above means that the number of operating vehicles n ₁ during the relatively short time t ₄ - _{t 5} is the number n 1 in operation during the relatively long time t ₂ - t ₃ and t ₆ - This is a formula that indicates that the number of vehicles in operation at t ₇ is even smaller than the smaller one of n ₀ and n ₂ , and if the above formula (2) does not hold, there is no need to change the number of vehicles in operation calculated in part A above. In other words, if n ₀ > n ₁ = n ₂ as a result of the load being concentrated in the morning like on Saturday, or on Sunday,
If the load is uniform during the day, such as on a special day, and becomes n ₀ = n ₁ = n ₂ , or if it is uneven in the afternoon, n ₀ = n ₁ < n ₂ , the number of operating vehicles calculated in Part A above will be used. Operating a power plant can maximize power generation efficiency. However, as shown in the load pattern curve in Figure 4, if the number of operating units is distributed such that equation (2) holds true, the number of operating units n ₁ in a relatively short period of time t ₄ to _{t 5} will be affected by start-up and stop losses. It is necessary to consider including the following.

Therefore, the number of operating vehicles calculation unit 24 calculates the number of operating vehicles as n ₀
When reducing the number of units from n 1 to n ₁ , first reduce the number of units by one and calculate the loss L _o using the following formula when n ₁ + 1 units (Part E).

ηn ₁ =f ₁ (L _pi /n ₁ ) ...(3) ηn ₁ +1=f ₁ (L _pi /n ₁ +1) ...(4) L _o =τ ₁ ×L _pi (1/ηn ₁ +1 −1/ηn ₁ ) ...(5) Here, ηn ₁ and ηn ₁ +1 are the power plant load
It represents the power generation efficiency when L _p1 is operated with the number of operating power generation units n ₁ and n ₁ +1, and is determined from the function curve f ₁ in FIG. 3. Also, τ ₁ is the time t ₄ to t ₅ , that is, τ ₁ = t ₅
−t represents ₄ .

Next, the operation number calculation section 24 compares the loss L _o calculated in the above section D with the stoppage and start-up loss L _S per power generation unit obtained from the power generation unit start-up and stoppage loss storage section 22, and calculates the following formula. Determine whether or not the requirements are satisfied (Obe).

L _o L _S ...(6) As a result, if the above equation (6) does not hold, even if there is a loss due to stopping and starting the power generation unit 4, the number of operating units n ₁ calculated in part A above will not be satisfied. Since there is less energy loss when the vehicles are operated, the number of vehicles in operation n ₁ is not intentionally changed.

However, if the above equation (6) holds, then the time t ₄ ~
By increasing the number of operating machines at t ₅ by one from the number of operating machines n ₁ calculated in Part A above, and setting n ₁ = n ₁ + 1 ...(7), the number of operating machines to be stopped and started is reduced by one (counter). Department).

Furthermore, the operating unit number calculation unit 24 compares the power generation unit load L _p1 /n ₁ when n ₁ = n ₁ +1 with the power generation unit minimum continuous operating load MINL obtained from the power generation unit maximum and minimum load storage unit 20, Determine whether the following formula is satisfied (Part K).

L _p1 /n ₁ MINL ...(7) As a result, if the above equation (7) does not hold, it can be seen that the power generation unit load at this time still has a margin up to the minimum continuous operation load of the power generation unit MINL. Returning to section D, the series of processes described above are repeated again.

On the other hand, if the above formula (7) holds true, by increasing the number of operating power generation units 4 by one in the above section, the power generation unit load L _p1 /n ₁ becomes less than or equal to the minimum continuous operation load of the power generation unit MINL, Since the power generation unit 4 cannot be operated, the number of units in operation is reduced by one at that time, and the number of units in operation n ₁ from time t ₄ to _{t 5} is determined as n ₁ =n ₁ −1 (8).

To summarize the above, the operating unit number calculation unit 24 first calculates the maximum efficiency operating number of power generation units n ₀ , n ₁ , n ₂ based on the load pattern curve given from the data setting device 3 without considering stoppage and startup losses. Calculate. Next, based on this calculation result, when it is necessary to stop and start the power generating units in a relatively short period of time τ ₁ = t ₅ - _{t 4} , there are two cases in which the number of stops and starts at that time is reduced, and a case in which the number of units stopped and started at that time is reduced. Based on the above formulas (3) to (6), it is determined which is more efficient based on the number of vehicles in operation. As a result, if it is more efficient to increase the number of operating units n ₁ calculated above, that is, to reduce the number of stopped and started units, then the generating unit load at that time is the minimum continuous operating load of the generating unit.
Determine the number of operating vehicles n ₁ within a range that does not become less than MINL.

In this way, when the most efficient operating number of power generation units 4 including start-up and stop losses is determined according to the load pattern curve, the process computer 2 determines the number of power generation units 4 in the power generation plant 5 based on this result. Performs start and stop control. At the same time, the load control device 1 performs load control so that the output load of each power generation unit 4 becomes the power generation unit load L _p1 / _n1 . This allows the power generation plant 5 to be operated at maximum efficiency.

Although the example above has been described in which the power generation unit startup and shutdown losses L _S are constant, the startup loss of the power generation unit 4 generally varies depending on the power generation unit 4 shutdown time. In other words, the longer the power generation unit 4 is stopped, the longer the power generation unit 4 is stopped.
A large amount of energy is required to start the power generation unit, and the power generation unit start-up loss increases. FIG. 6 shows how the starting loss changes with respect to the stopping time of the power generating unit at this time, in which the horizontal axis shows the stopping time of the power generating unit and the vertical axis shows the starting loss of the power generating unit. Therefore, the case where the power generation unit starting loss is variable will be explained below.

FIG. 7 is an overall configuration diagram of a power plant operation control system showing an embodiment of the present invention. In the figure, the same reference numerals as in FIG. This is the point at which the power generation unit operation priority order signal _S5 is transmitted.

FIG. 8 shows a functional block diagram of the process computer 2 in FIG. 7. In the diagram, the same reference numerals as in FIG. A power generation unit stop time processing unit ₂₆ is provided which integrates the stop time of the corresponding power generation unit 4 based on S25 and outputs a power generation unit stop time signal _S26 obtained by the integration to the operating unit number calculation unit 24. At this point, a power generation unit operation priority order signal S ₅ is also transmitted from the input processing section 23 to the operation number calculation section 24 . In addition, the above power generation unit stop signal _S25 is the seventh
The power generation unit operation monitoring control signal _S2 shown in the figure is sent to the input processing section 23 of the process calculator 2 for each power generation unit 4.
It is given in response to.

With the above configuration, in this embodiment, the startup loss of the power generation unit is calculated according to the power generation unit stoppage time, and the number of operating power generation units is operated so that the efficiency of the power generation plant including startup and stoppage losses is maximized. Control.

That is, as shown in the flowchart of FIG. 9, the operating unit calculation section 24 reads the power generation plant load pattern and the power generation unit operation priority order in section A, and performs the same processing as explained in FIG. 5 of the above embodiment. After executing parts , C, and E, in part A, priority is given to the operation of the power generation unit read in part A, which is started as the first power generation unit due to the increase in load from time t ₅ to time t ₆ in Fig. 4. Determine from the order. Next, the stop time of the power generation unit is determined. In this case, the stop time T _STP corresponding to each power generation unit is determined by the power generation unit stop time processing section 2 in FIG.
6 and is stored.

When the operating unit calculation unit 24 obtains the stop time T _STP of the power generation unit to be started from the power generation unit stop time processing unit 26, it calculates the power generation unit start-up loss L _STR from the power generation unit start-up loss curve f ₂ shown in FIG. Calculated using the formula below (Part 2).

L _STR = f ₂ (T _STP ) ...(9) Furthermore, the number of operating units calculating section 24 calculates the power generation unit starting loss L _STR calculated in the above section and from the power generation unit starting and stopping loss storage section 22 in Fig. 8. Based on the obtained stop loss L _STR of the power generation unit 4, the stop and start losses L _S from time t ₃ to _{t 4} and from t ₅ to _{t 6} in Fig. 4 are calculated using the following formula (section 3). .

L _S = L _STR + L _STP ...(10) Next, the operating unit number calculation unit 24 calculates the loss due to the change in the number of operating units in the O section, based on the stop and start losses L _S calculated in the S section, as in the previous example. After comparing and determining the magnitude of L _o and the stop and start losses L _S , the operating efficiency of the power generation plant 5 is maximized, including the start and stop losses of the power generation unit 4 through the processing of the F, K and H parts. The number of operating power generation units 4 is determined. As a result, the power generation plant 5 can be used more accurately than in the previous embodiment.
It becomes possible to determine the number of operating power generation units 4 that maximizes the operating efficiency.

〔Effect of the invention〕

As described above, according to the present invention, in a power generation plant consisting of a plurality of power generation units, if an operator only sets and inputs the daily power generation plant load pattern, the power generation unit can be started up and the power generation plant can be operated including stoppage losses. The number of operating power generation units that maximizes efficiency can be calculated. In addition, at this time, the power generation unit to be started next is determined in advance, and the startup loss for that power generation unit is determined from the stop time, and the power generation efficiency loss is calculated. It will be possible to control the operation even more efficiently.

[Brief explanation of drawings]

Fig. 1 is an overall system configuration diagram of a power generation plant operation control device showing an embodiment of the present invention, Fig. 2 is a functional block diagram of the process computer of Fig. 1, Fig. 3 is a power generation unit load efficiency curve diagram, Fourth
Figure 5 is a load pattern curve diagram of a power generation plant, Figure 5 is a flowchart showing the processing in the operation number calculation section of Figure 2, Figure 6 is a starting loss curve diagram of a power generation unit, and Figure 7 is a diagram of another power generation unit according to the present invention. An overall system configuration diagram of a power plant operation control device showing an example,
FIG. 8 is a functional block diagram of the process computer shown in FIG. 7, and FIG. 9 is a flowchart showing the processing in the operation number calculation section of FIG. 1...Load control device, 2...Process computer,
3...Data setting device, 4...Power generation unit, 5...
... Power generation plant, 20 ... Power generation unit maximum and minimum load storage section, 21 ... Power generation unit load efficiency storage section, 22 ... Power generation unit start and stop loss storage section, 23 ... Input processing section, 24 ... Number of operating units calculation Section 25...Target operation number storage section, 26...Power generation unit stop time processing section.

Claims (1)

[Claims] 1. In a power generation plant operation control device that controls starting and stopping of a plurality of power generation units according to a power generation plant load pattern input via a data setting device, the power generation unit maximum load stored in advance in conjunction with the power generation plant load pattern is used. A method for calculating the number of operating power generation units that maximizes power generation efficiency from means for calculating the power generation unit based on a predetermined operating priority order of the power generation units and the stop time of the power generation unit to be started; means for storing the start-up and stop loss of the power generation unit; and means for calculating the power generation efficiency loss and start-up. , a power generation plant operation control device comprising means for comparing the amount of power generation unit with a stop loss amount, and means for determining the number of operating power generation units based on the comparison result of the means.