JPH0148367B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a power generation plant control method and apparatus, and particularly to a power generation plant suitable for enabling optimal operation control of a power generation plant when transitioning to on-site isolated operation. The present invention relates to a control method and device.

[Background of the Invention] When a system fault occurs in a power generation plant, it is important to continue operation with a single load within the plant or a local system load, and then re-parallel the plant when the system fault recovers to quickly return to the initial load. This is extremely effective from the perspective of stable supply.

The functions that perform this kind of driving are collectively called
This is called Fast Cut Back, and will be referred to below as
It is called FCB.

However, in the current FCB operation, 1. Turbine life consumption is large.

2 The turbine operates at a point where internal efficiency is poor.

3. Turbine start-up times are currently becoming shorter, and it is more advantageous to restart the plant after it has been shut down than to continue low-load operation.

4 Turbine exhaust erosion occurs due to spray water.

5 Boiler control is difficult due to low load operation.

Although many problems have been pointed out, we are in a situation where we have no choice but to sacrifice the above-mentioned problems 1 to 5 from the viewpoint of stable power supply.

Recently, the number of power plants with FCB function has been increasing, and in power plants that consist of multiple units, there is a possibility that all units will be in FCB operation, and depending on the frequency of FCB operation, the life of the turbine will be reduced. This can significantly increase the amount of water and reduce the service life of the turbine.

These events will be explained in more detail with reference to the drawings.

FIG. 1 shows an example of a power generation plant commonly used in the past.

What is shown in this Figure 1 is 6 of groups A to F.
It is formed by a group (6 units).

Group A is configured by connecting a turbine 1a, a generator 2a, a transformer 3a, and a circuit breaker 4a in series.By driving the turbine 1a, the generator 2a generates electricity, and the electrical output is transferred to the generator transformer 3a. , is supplied to the power transmission line 5 through the circuit breaker 4a. Further, a part of the electrical output is used as a load consumed within the power generation plant, that is, as an in-house load. Note that this in-house load includes unit in-house load 9a consumed for each unit,
It is classified into a common in-house load 13 that is common to each unit. In FIG. 1, the former unit transformer 6a is connected between the generator 2a and the generator transformer 3a.
It is supplied through circuit breakers 7a, 7a' and distribution board 8a. The latter is similar to the former, the station transformer 11,
In addition to being supplied through the circuit breakers 10'', 10' and the distribution board 12, since the load is common to the six units, the load is supplied from the power transmission line 5 through the circuit breakers 10, 10', the station transformer 11, and the distribution board 12. However, the latter is normally supplied from the power transmission line 5.

Group B that constitutes the power generation plant
Group F is also configured in the same manner as group A described above.

In the conventional power generation plant configured as described above, when a system accident or the like occurs, the circuit breaker 4a is opened, that is, disconnected from the system, and the power generation capacity is instantaneously reduced to the station load. This state is 6 from group A to group F.
If this occurs in all units, all units will
FCB operation (Unit station load + Common station load)
It will be operated in

As mentioned above, when all units are in FCB operation, all units will consume turbine life at the same rate, and if the FCB operation time becomes longer, the turbine life consumption will become extremely large. In addition, all units can be operated with low load.
In other words, the vehicle will be operated under less efficient conditions. It is also not a good idea from an economic point of view.

FIG. 2 shows an example of the operating load of each unit.

In the example shown in Fig. 2, No. 1 and 2 units are
40% load, No. 3 is 80% load, No. 4, 5, 6 is 100
% load. Further, the unit internal load of each unit is 3% load for each unit, and the common internal load is 3% load for the total of 6 units, which is very small. Therefore, when shifting to FCB operation from the above state,
Turbine life consumption is the largest for Nos. 4, 5, and 6, followed by the smallest for No. 3, No. 1, and 2. Turbine life consumption is lower when switching to FCB operation than under low load. I know it's small.

Next, FIG. 3 shows conventional plant operation control.

In this figure 3, the electrical output 1 of each unit
5, the power supply command, and other requested loads 14, and supplies a load increase/decrease signal 16 to each unit to change the electrical output 15 of the unit. Plant operation is controlled by repeatedly executing this operation, so if the required load 14 decreases due to a system accident or the like, the system shifts to FCB operation regardless of the operating load of each unit.

Therefore, if all six units were operated at 100% load and shifted to FCB operation, the turbine life consumption would be very large, and depending on the frequency of FCB operation, all six units would exceed the expected service life. There is a possibility that modifications such as rotor replacement may be required beforehand. Furthermore, if the turbine life consumption is not managed, a serious accident may occur.

[Purpose of the invention]

It is an object of the present invention to provide a power generation plant control method that can reduce turbine life consumption during transition to FCB operation, and another object of the present invention is to provide a power generation plant control method that can further improve economic efficiency and reliability during FCB operation. Another object of the present invention is to provide a control method for a power plant, and a further object of the present invention is to provide a control device for a power plant that can reliably implement the method of the invention.

[Summary of the invention]

The first invention of the present invention is as claimed in claim 1.
As described in section 1, in a power generation plant composed of multiple units, when transitioning to on-site isolated operation due to the occurrence of an abnormal condition such as a system failure, the electrical output of each unit is determined, and the unit during on-site isolated operation is This method is characterized in that the number of operating units and the units to be operated are selected, and by this method, it is possible to reduce the turbine life consumption at the time of transition to FCB operation.

In addition, the second invention of the present invention is, as stated in claim 3, in a power generation plant constituted by a plurality of units, when an abnormal state occurs in the power generation plant such as a system failure, the power generation plant shifts to isolated operation within the plant. At the same time, the electrical output of each unit is judged, the number of units to be operated during isolated operation in the station is selected, the units to be operated are selected, and the required internal load corresponding to the selected number of units is calculated. This method is characterized in that the load is distributed among each unit, and by this method, it is possible to further improve the economic efficiency and reliability during FCB operation.

Furthermore, the third aspect of the present invention is that, as set forth in claim 5, a plant operation control device that controls each unit is configured to shift to in-plant isolated operation due to the occurrence of an abnormal state of the power plant such as a system accident. This system is characterized by the addition of a unit operation number determination section that determines the electrical output of each unit and selects the number of units to be operated during independent operation within the station, and an operation unit determination section that selects the units to be operated. With this apparatus, the method of the first invention can be reliably carried out.

As described in claim 6, the fourth aspect of the present invention is that the plant operation control device that controls each unit is configured to shift to in-plant isolated operation due to the occurrence of an abnormal state of the power plant such as a system accident. At this time, there is a unit operation number determination section that determines the electrical output of each unit and selects the number of units to be operated during independent operation within the station, an operation unit determination section that selects the units to be operated, and a unit corresponding to the selected number of units. This device is characterized by the addition of a unit operating load calculation section that calculates the required internal load and a unit operating load distribution section that distributes the load to each selected unit. A certain method can be implemented reliably.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 4 shows an example of a control device for a power plant for carrying out the method of the present invention, and shows a case where the power block is composed of six units.

In FIG. 4, when an abnormal state of the power generation plant due to a system accident occurs and the FCB signal is input to the plant operation control device 18, the electric outputs 15a to 15f of each unit are input to the unit electric output calculation section 17, Calculate the operating load status and total electrical output of each unit. The difference between the electrical output calculated by the unit electrical output calculation section 17 and the required electrical output from the plant operation control device 18, that is, the load increase/decrease, is calculated, and the load increase/decrease signal 16 is fed back to the plant operation control device 18. Ru. In the plant operation control device 18, the FCB
By inputting signals, it determines the operating load of each unit and the designation by the operator, selects the number of operating units when transitioning to isolated operation within the station, selects the units to be operated, distributes the operating load, and calculates the required electrical output. This required electrical output is fed back to each unit to control the operation of the turbine, steam generator, and generator. The generator electrical output controlled by the requested electrical output is again input to the unit electrical output calculation section 17, and from then on, the above-mentioned process is sequentially repeated to implement the power generation plant operation control method of the present invention. It becomes possible to do so.

Next, FIG. 5 shows an example of a plant operation control device.

In FIG. 5, due to the occurrence of an abnormal state in the power generation plant, the FCB signal 21 and the requested electrical output (Load
Demand) 19, operating unit number specification 20, operating unit number specification 22, and each unit electrical output 15a to f are input to the plant operation control device 18. Based on these input data, the plant operation control device 18 selects the number of units, selects the operating unit number, and distributes the operating load when transitioning to individual plant operation, and sends control signals to control the operation of each unit. send.

In order to ensure that the plant operation control device 18 performs the above-mentioned functions, the plant operation control device 18 controls the number of units in operation determining section 2.
3. It is composed of an operating unit determining section 24, a unit operating load calculating section 25, a unit operating load distributing section 26, and a unit operating load determining section 27, the contents of which will be specifically explained below.

FIG. 6 shows a detailed block diagram of the unit operation number determination section 23.

When the FCB signal 21 is input to the operating unit number determination section 23, the operating unit number determination section 28 first checks whether the number of operating units has been designated. If the number of operating machines 20 has been inputted by an operator or the like, the designated number selecting section 32 unconditionally gives priority to the number of operating machines 20 and determines the number of machines. On the other hand, if the operating number designation 20 has not been input, the required electrical output determination unit 29 determines whether there is a required load such as a power supply command. In other words, if 250% load is required as the required electrical output, it is necessary to transmit the 250% load immediately after the FCB signal is input, and at least three units must be shifted to in-station load operation. Therefore, when the required electrical output 19 is inputted to the required electrical output determination section 29, the minimum number of units that satisfy the required electrical output 19 is selected by the required electrical output equivalent number selection section 30. In addition, the required electrical output 1
If 9 is not input, MIN. 1 unit is selected by the MIN. operation number selection section 31 as the number of units in operation. As mentioned above, the selected number of operating units (any one of 30, 31, or 32) is determined by the operating unit determining section 2 in the next process.
4 is input.

FIG. 7 shows a detailed block diagram of the operating unit determination section 24.

In response to the input of the number of operating units determined by the operating unit number determination section 23, the unit number designation determination section 33 first checks whether or not the unit number designation 22 is present. Unit No. designation 22
If there is, the specified unit number determination section 37
In this step, the specified unit number is given priority and the unit number is determined. If there is no unit number designation 22, the number of units in operation determining section 34 determines whether the number of units in operation is plural or one. When MIN. 1 unit is selected as the number of operating units, the unit number (1 unit) determining section 36 selects the unit operating at the lowest load based on the input of the unit electrical outputs 15a to 15f. this is,
This is because it is possible to keep the turbine life consumption lower by shifting a unit operating at a low load to FCB operation compared to a unit operating at a high load. However, if all six units or multiple units are operated at the same minimum load, it is not possible to select one unit, and the next step, the unit efficiency determination section 36', determines the most efficient one. A unit with a high value will be selected and this unit will be transferred to FCB operation. This efficiency ranking can be determined based on performance tests conducted during test runs and the like. On the other hand, unit operation number determination section 34
If it is determined that there is a plurality of units, the unit number (plurality) determining section 35 selects units corresponding to the required number of operating units from the unit operating at the lowest load. (The unit number (plurality) determining section 35 in Fig. 7 shows an example in which three units are determined.) However, in this case as well, it is possible that each unit is operated with the same load. Although this is conceivable, in such a case, the unit efficiency determining section 35' determines the required number of units based on the units with higher efficiency. (In the unit efficiency determination section 35' in Fig. 7, the required number of operating units is 3.
In the case of units, the unit number operating at the lowest load is selected first, then the most efficient unit number is selected.
An example in which three units, No. 2 and then No. 4, are selected is shown).

The unit numbers (corresponding to the number of operating units) selected as described above are input to the unit operating load calculation section 25.

FIG. 8 shows a detailed block diagram of the unit operating load calculating section 25, unit operating negative distribution section 26, and unit operating load determining section 27.

The operating unit number (number of units in operation) determined by the operating unit determining section 24 is input to the unit operating load calculating section 25, which calculates the operating load at the time of transition to FCB operation. In other words, the required internal load (FCB
Calculate the sum of the unit internal load and common internal load corresponding to the number of units to be put into operation.
The unit internal load calculation section 38 calculates the unit internal load corresponding to the number of operating units at the time of transition to FCB operation. As an example, if there are 3 units, (total unit internal load) = 3 x UA (kW), where UA: unit internal load/1 Unit.

Next, the required internal load calculation section 39 calculates the total internal load, that is, the sum of the unit internal load and the common internal load. As an example, if there are 3 units, (required internal load) = 3 x UA + CA where UA: unit internal load/1 unit CA: common internal load/plant.

The required internal load calculated as described above is input to the unit operating load distribution section 26, 26'.
The unit operating load distribution sections 26, 26' determine what percentage of the required internal load is to be placed on each unit when the selected unit shifts to FCB operation. Unit operation load distribution section 26
The common station load is assigned to the unit with the highest operating efficiency among the selected units.For example, as shown in the unit operating load distribution section 26 in Fig. 8, three units are selected. In this case, the common station load is applied to the No. 3 unit with the highest operating efficiency, and the No. 3 unit is operated with the above-mentioned load (UA + CA) during FCB operation,
The other No. 1 and No. 2 units will be operated with the unit's internal load. On the other hand, apart from the above,
As shown in the unit operating load distribution section 26', when a plurality of units are selected, each of the selected units can be operated with the same load. That is, the required internal load is distributed so that the number of units in operation has the same load as shown in the following equation.

Operating load of each unit) = (N x UA + CA) / N (
kW)=UA+CA/N(kW) Here, N: number of units.

The operating load distributed by either of the unit operating load distribution sections 26, 26' is transferred to the unit operating load determination section 27.

The unit operating load determination section 27 calculates the difference between the load distributed by the unit operating load distribution section 26 or 26' and the operating load before the occurrence of FCB.
It is determined by what percentage the load should be reduced or increased to reach the station load, and which units (unselected units) should be tripped in FCB operation. In other words, the unit operating load determining section 27 generates the load increase/decrease signal 16 at the time of transition to FCB operation.

As in the above example, the plant operation control device 1
Based on the calculation result of step 8, a plant operation stop command signal (load increase/decrease signal 16) is transmitted,
By controlling the plant operation after the occurrence of FCB, the plant operation control method of the present invention can be performed fully automatically and is very effective.

The functions and storage capacity required for the above-mentioned plant operation control device 18 are relatively small, so when installed as a dedicated arithmetic unit, a small microcomputer is sufficient and the equipment cost is not high. In addition, since a small-capacity device is sufficient, it is easy to incorporate, for example, by utilizing the extra capacity of a large computer for controlling and monitoring the entire power generation plant.

〔Effect of the invention〕

According to the first aspect of the present invention described above, in a power generation plant composed of a plurality of units, when the power generation plant shifts to isolated operation due to the occurrence of an abnormal state such as a system failure, the electric output of each unit is determined. Since the number of units to be operated and the units to be operated are selected during isolated operation within the plant, this has the effect of reducing the turbine life consumption when transitioning to FCB operation, thus reducing the turbine service life. It has the effect of preventing

Furthermore, according to the second aspect of the present invention, in a power generation plant composed of a plurality of units, when the power generation plant shifts to isolated operation due to the occurrence of an abnormal state such as a system failure, the electric output of each unit is determined. In addition to selecting the number of operating units and the units to be operated during isolated operation within the station, the necessary internal load corresponding to the selected number of units is calculated, and the calculated load is distributed to each unit. This has the effect of further improving economic efficiency and reliability during FCB operation.

Furthermore, according to the third aspect of the present invention, the plant operation control device that controls each unit is configured to determine the electrical output of each unit when the power plant shifts to isolated operation due to the occurrence of an abnormal state such as a system failure. The method of the first aspect of the invention can be reliably carried out because it includes an operating unit number determining section that selects the number of operating units during isolated operation within the plant, and an operating unit determining section that selects the units to be operated. There is a potential effect.

According to the fourth aspect of the present invention, the plant operation control device that controls each unit is configured to determine the electrical output of each unit when the power plant shifts to isolated operation due to the occurrence of an abnormal state such as a system failure. a unit operation number determination section that selects the number of operating units during isolated operation within the station; an operation unit determination section that selects the units to be operated; and a unit operating load calculation section that calculates the required internal load corresponding to the selected number of units. Since a unit operating load distributing section is added for distributing load to each selected unit, there is an effect that the method of the second aspect of the present invention can be carried out reliably.

[Brief explanation of drawings]

Figure 1 is a system diagram of a power generation plant commonly used in the past, Figure 2 is a diagram showing an example of the operating load of each unit that makes up the power plant, and Figure 3 is a diagram showing conventional plant operation control. , FIG. 4 is a block diagram showing an example of a device for implementing the plant operation control method of the present invention, FIG. 5 is a block diagram showing an example of a plant operation control device configured to implement the present invention, and FIG. Figure 6 is a detailed block diagram of the operating unit number determining section, Figure 7 is a detailed block diagram of the operating unit determining section, and Figure 8 is a detailed block diagram of the unit operating load calculation section, unit operating load distribution section, and unit operating load determining section. It is a diagram.
1a-f...turbine, 2a-f...generator, 3
a-f... Generator transformer, 4a-f... Circuit breaker, 5... Power transmission line, 6a-f... Unit transformer, 7a-f, 7a'-f'... Circuit breaker, 8a-f...
...Distribution board, 9a-f...Unit station load, 1
0, 10', 10''...Breaker, 11...Station transformer, 12...Distribution board, 13...Common station load, 14...Required load (Load Demand),
15...Each unit electrical output, 16...Load increase/decrease signal, 17...Unit electrical output calculation section, 18...
...Plant operation control device, 19...Required electrical output, 20...Number of operating units specified, 21...FCB signal,
22...Operating unit number designation, 23...Unit operation number determination unit, 24...Operating unit determination unit,
25...Unit operating load calculation section, 26, 26'
...Unit operating load distribution section, 27...Unit operating load determining section, 28...Number of operating units determining section, 29
...Required electrical output determination section, 30... Required electrical output equivalent number selection section, 31... MIN. operating number selection section, 32... Specified number selection section, 33... Unit
No. designation determination section, 34...Unit operation number determination section, 35...Unit No. (plurality) determination section, 36...
...Unit No. (1 unit) determining section, 37...Specified unit number determining section, 38...Unit internal load calculation section, 39...Required internal load calculation section.

Claims (1)

[Scope of Claims] 1. In a power generation plant composed of a plurality of units, when shifting to on-site isolated operation due to the occurrence of an abnormal condition such as a system failure, the electrical output of each unit is determined, and the A power generation plant control method characterized by selecting the number of operating units and selecting the units to be operated. 2. The method of controlling a power generation plant according to claim 1, characterized in that the units to be operated are selected from units that are operated at a low load. 3. In a power generation plant composed of multiple units, when shifting to on-site isolated operation due to the occurrence of an abnormal condition such as a system failure, the electrical output of each unit is determined, and the number of units to be operated during on-site isolated operation is selected. A control method for a power generation plant, comprising: selecting a unit to be operated; calculating a required internal load corresponding to the number of selected units; and further distributing the calculated load to each unit. 4. The method for controlling a power generation plant according to claim 3, characterized in that the units to be operated are selected from units that are operated at low loads. 5. In a power generation plant equipped with a plurality of units and a plant operation control device that controls each unit, when the power plant operation control device shifts to in-house isolated operation due to the occurrence of an abnormal condition such as a system accident, each unit A control device for a power generation plant, characterized in that it is further equipped with a number-of-operating-unit determining unit that determines the electrical output of the unit and selects the number of operating units during isolated operation within the plant, and an operating unit determining unit that selects the units to be operated. . 6 In a power generation plant equipped with a plurality of units and a plant operation control device that controls each unit, when the power plant operation control device shifts to in-house isolated operation due to the occurrence of an abnormal condition such as a system accident, each unit A unit operation number determination section that judges the electrical output of the unit and selects the number of units to be operated during isolated operation within the station, an operation unit determination section that selects the units to be operated, and a necessary station load corresponding to the selected number of units. 1. A control device for a power generation plant, comprising a unit operating load calculation section for calculating the unit operating load, and a unit operating load distribution section for distributing the load to each selected unit.